Climatic variables and malaria transmission dynamics in Jimma town, South West Ethiopia

Spatial modeling, prediction and seasonal variation of malaria in northwest Ethiopia

Objectives

The aim of this study was to determine the spatial modeling, seasonal variation of malaria and making prediction map of malaria in northwest Ethiopia.

Results

The overall average cumulative annual malaria incidence during the study period was 30 per 100 populations at risk. The highest proportion (29.2%) was observed from June 2015 to October 2016. In temporal analysis of clusters, the epidemic was observed from 2015/7/1 to 2016/12/31 throughout the study period in all districts. Hotspot areas with high clusters (p < 0.001) were observed in Metema district it accounts 18.6% of the total malaria cases. An area of high median predicted incidence proportion (> 50%) was seen in the southwest part of the region. Most of the northern part of the study area was predicted to have a low median incidence proportion (< 10%).

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4305-1) contains supplementary material, which is available to authorized users.

Ten years malaria trend at Arjo-Didessa sugar development site and its vicinity, Southwest Ethiopia: a retrospective study

BACKGROUND

The trend analysis of malaria data from health facilities is useful for understanding dynamics of malaria epidemiology and inform for future malaria control planning. Changes in clinical malaria characteristics, like gender and age distribution are good indicators of declining malaria transmission. This study was conducted to determine the malaria trend at Arjo-Didessa sugar development site and its vicinity, southwest Ethiopia, from 2008 to 2017.

METHODS

Monthly malaria confirmed case data from 2008 to 2017 was extracted from 11 health facilities based on clinical registers at Arjo sugar development site and its vicinity, southwest Ethiopia. Both positivity rate and malaria incidence rate were calculated. Changes in malaria parasite species and seasonality were analysed; age structure and gender distribution were compared between different study periods. Trend in malaria incidence and climatic impact were analysed and past LLIN and IRS campaigns were used as dynamics modifier.

RESULTS

Over a period of 10 years, 54,020 blood film were collected for malaria diagnosis in the health facilities at the area, of which 18,049 (33.4%) were confirmed malaria cases by both microscopically and RDT. Plasmodium falciparum, Plasmodium vivax, and mixed infection (P. falciparum and P. vivax) accounted for 8660 (48%), 7649 (42.4%), and 1740 (9.6%) of the malaria cases, respectively. The study also revealed that P. vivax was the predominant over P. falciparum for 4 years (2010, 2014, 2015 and 2016). There was a remarkable reduction of overall malaria infection during the 10 years. Malaria has been reported in all age groups, but age distribution showed that vast majority of cases were adults age 15 years and above 13,305 (73.7%). In all age groups, males were more significantly affected than females (χ² = 133.0, df = 2, P < 0.0001). Moreover, malaria positivity rate showed a strong seasonality (χ² = 777.55, df = 11, P < 0.0001). However, malaria cases were reported in all seasons across 10 years in the study area.

CONCLUSION

In general, malaria positivity showed a declining trend over 10 years period in the area. However, current prevalence shows it is public health burden and needs attention for further intensification of interventions. In the study area, both P. falciparum and P. vivax co-exist and P. vivax is more prevalent than P. falciparum in almost half of the years. Therefore, malaria interventions should be strengthened in the study area.

Trend analysis of malaria prevalence in Halaba special district, Southern Ethiopia

OBJECTIVE

The study aimed to determine the prevalence of malaria in Halaba special district, Southern Ethiopia, from 2013 to 2017.

RESULTS

Of a total 583,668 malaria suspected cases examined during the study period, 55,252 (9.5%) were microscopically confirmed to be positive for malaria, at the rate of 27,712 (50.2%) females and 27,540 (49.8%) males (P = 0.95). The highest prevalence of 8454 (15.3%) malaria cases were observed in Halaba health center, followed by Halaba district hospital, at 7290 (13.2%), while the lowest cases, 1765 (3.2%), were confirmed in Wejago health center. The highest prevalence of malaria, 25,716 (46.5%), was registered among the age group ≥ 15 year old (P = 0.006). Plasmodium vivax and Plasmodium falciparum were the two major malaria parasites detected in this study, with the prevalence of 33,855 (62.3%) and 21,397 (38.7%), respectively (P = 0.0001). The detected high prevalence of P. vivax in this study may clearly indicate that more attention has been given to control P. falciparum strains in the study area. This may be a great challenge for the achievement of malaria elimination goals. Therefore, all concerned bodies should act collaboratively to combat the high prevalence of P. vivax from the study district.

Variability in malaria cases and the association with rainfall and rivers water levels in Amazonas State, Brazil

Understanding the relations between rainfall and river water levels and malaria cases can provide important clues on modulation of the disease in the context of local climatic variability. In order to demonstrate how these relations can vary in the same endemic space, a coherence and wavelet phase analysis was performed between environmental and epidemiological variables from 2003 to 2010 for 8 municipalities (counties) in the state of Amazonas, Brazil (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá, and São Gabriel da Cachoeira). The results suggest significant coherences, mainly on the scale of annual variability, but scales of less than 1 year and of 2 years were also found. The analyses show that malaria cases display a peak at approximately 1 and a half months before or after peak rainfall and on average 1-4 months after peak river water levels in most of the municipalities studied. Each environmental variable displayed distinct local behavior in time and in space, suggesting that other local variables (e.g. topography) may control environmental conditions, favoring different patterns in each municipality. However, when the analyses were performed jointly it was possible to show a non-random order in these relations. Although environmental and climatic factors indicate a certain influence on malaria dynamics, surveillance, prevention, and control issues should not be overlooked, meaning that government public health interventions can mask possible relations with local hydrological and climatic conditions.

Trend analysis of malaria prevalence in Raya Azebo district, Northern Ethiopia: a retrospective study

Objective

Malaria remains still the leading cause of outpatient visits and death in Ethiopia. However, little is known about its trend in the study area. Hence, this study was aimed to assess 6-year (2011–2016) trend of malaria prevalence. A retrospective cross-sectional study design was conducted to assess 6-year trends of malaria prevalence in Raya Azebo district, North Ethiopia. Malaria case recorded from 2011 to 2016 was extracted using similar format.

Result

A total of 29,930 malaria cases were reported from 2011 to 2016. Of these, 23,018 were confirmed cases while, 6912 were reported as clinical cases. Plasmodium falciparum (56.9%) was the most dominated species. Malaria was reported in all age group and both sexes with highest in male and > 15 age categories. The highest peak malaria distribution was occurred in spring season. The overall trends of malaria case were increased in the past 6 years (2011–2016) with exception slightly decreased from 2012 to 2013. Therefore, Strong effort is needed to improve malaria prevention and controlling method in study area.

Treatments used for malaria in young Ethiopian children: a retrospective study

Background

In Ethiopia, medicinal plants have been used to treat different diseases, including malaria, for many centuries. People living in rural areas are especially noted for their use of medicinal plants as a major component of their health care. This study aimed to study treatment-seeking and prioritize plants/plant recipes as anti-malarials, in Dembia district, one of the malarious districts in Northwest Ethiopia.

Methods

Parents of children aged under 5 years who had had a recent episode of fever were interviewed retrospectively about their child’s treatment and self-reported outcome. Treatments and subsequent clinical outcomes were analysed using Fisher’s exact test to elicit whether there were statistically significant correlations between them.

Results and discussion

Of 447 children with malaria-like symptoms, only 30% took the recommended first-line treatment (ACT) (all of whom were cured), and 47% took chloroquine (85% cured). Ninety-nine (22.2%) had used medicinal plants as their first-choice treatment. Allium sativum (Liliaceae), Justicia schimperiana (Acanthaceae), Buddleja polystachya (Scrophulariaceae) and Phytolacca dodecandra (Phytolaccaceae) were the most frequently used. Justicia schimperiana was the one associated with the best clinical outcomes (69% self-reported cure rate). However, the difference in clinical outcomes between the plants was not statistically significant.

Conclusion

In this study, only 30% of children took the recommended first-line treatment. 22% of children with presumed malaria were first treated with herbal medicines. The most commonly used herbal medicine was garlic, but J. schimperiana was associated with the highest reported cure rate of the plants. Further research is warranted to investigate its anti-malarial properties.

The 2015-2016 malaria epidemic in Northern Uganda; What are the implications for malaria control interventions?

Vector control and effective case management are currently the backbone strategies of malaria control. Kitgum district, an area of perennial holoendemic malaria transmission intensity in Northern Uganda, appears to have experienced a malaria epidemic in 2015. This study aimed to describe the malaria trends in Kitgum General Hospital from 2011 to 2017 in relation to climatic factors and the application of population-based malaria control interventions. Hospital records were examined retrospectively to calculate malaria normal channels, malaria cases per 1000 population, test positivity rates (TPR) and to enumerate pregnancy malaria, hospitalizations and deaths. Climatic factors (humidity, temperature and rainfall) and population-based malaria control interventions that had been applied during this period were described. Kitgum district experienced an epidemic between the years 2015 and 2016; the malaria burden rose above the established normal channels. At its peak the number of malaria cases attending KGH was over 20 times above the normal channels. The total number of cases per 1000 population increased from 7 in 2014 to 113 in 2015 and 114 in 2016 (p value for trend <0.0001). Similarly, TPR increased from 10.5% to 54.6% between 2014 and 2016 (p value for trend <0.0001). This trend was also observed for malaria attributable hospitalizations, and malaria in pregnancy. There were no significant changes in any of the climatic factors assessed (p value = 0.92, 0.99, 0.52 for relative humidity, max temperature, and rainfall, respectively). The malaria upsurge occurred in conjunction with a general decline in the use and application of malaria control interventions. Specifically, indoor residual spraying was interrupted in 2014. In response to the epidemic, IRS was reapplied together with mass distribution of long-lasting insecticide treated nets (LLINs) in 2017. Subsequently, there was a decline in all malaria indicators. The epidemic in Kitgum occurred in association with the interruption of IRS and appears to have abated following its re-introduction alongside LLINs. The study suggests that to enable malaria elimination in areas of high malaria transmission intensity, effective control measures may need to be sustained for the long-term.

Decline in malaria incidence in a typical county of China: Role of climate variance and anti-malaria intervention measures

Malaria is an important vector-borne disease which is widespread in tropical and subtropical areas worldwide as well as in south China. Previous research has separately focused on the association between malaria incidence and meteorological variables or between malaria incidence and anti-malaria intervention measures in China, especially in Yunnan Province. Therefore, a typical county, Tengchong County, in Yunnan Province with high malaria incidence was selected as the study area to investigate the integrated influence of climate variance and anti-malaria intervention measures. Malaria incidence and meteorological variables were analyzed with a 2-month lag. The variables include average monthly temperature, minimum temperature, maximum temperature, cumulative precipitation, wind speed, maximum wind speed, relative humidity and minimum relative humidity. First, the principal component analysis was introduced to investigate the relationship between malaria incidence and meteorological variables; classification and regression trees were used to clarify contributions of key meteorological variables to malaria incidence afterwards. Second, based on existing anti-malaria intervention measures and above results, the integrated impact of climate variance and anti-malaria interventions on interannual trends of malaria incidence was analyzed. High malaria incidence occurred under one of the two meteorological conditions: 1) high minimum temperature combined with high minimum relative humidity or both precipitation and minimum relative humidity above middle level; 2) middle minimum temperature combined with both precipitation and minimum relative humidity below middle levels. Moreover, the steep interannual decline of malaria incidence in Tengchong was determined by slight climate variance and persistent anti-malaria intervention measures during malaria epidemics, predominantly by the latter. These findings will provide evidence data for developing malaria surveillance strategies in China.

Analysis of the trend of malaria prevalence in Ataye, North Shoa, Ethiopia between 2013 and 2017

Background

Malaria is one of the major public health problems worldwide. In Ethiopia, there is a significant decline in disease burden; however, the overall trend of malaria prevalence is not studied or well-documented in different localities. Hence, the initiation of this study was to analyse the 5-year trends of malaria prevalence in Ataye, North Shoa, Ethiopia.

Methods

A retrospective laboratory record review was conducted in Ataye Hospital, North-Shoa, Ethiopia. Malaria data reported from 2013 to 2017 were carefully reviewed from January to March 2018.

Results

A total of 31,810 blood films were prepared and examined from malaria-suspected patients at Ataye District Hospital from 2013 to 2017. Of the examined blood films, 2670 (8.4%) were microscopically confirmed malaria cases. The trend of malaria prevalence in the present study seems non- fluctuating. Plasmodium falciparum and Plasmodium vivax accounted for 2087 (78.2%) and 557 (20.9%) cases, respectively. From total positive cases, 1.0% of cases were mixed P. falciparum/P. vivax infections, and that no Plasmodium malariae and Plasmodium ovale infections were found by malaria microscopists. Malaria cases were higher in males 1584 (5.0%) than females 1086 (3.4%). With regard to age groups, higher numbers of malaria cases were observed in age group 15–45 years old. Malaria cases were high in spring (September to December), which is a peak malaria transmission period in Ethiopia.

Conclusion

Malaria is still among the major public health problems in the country. P. falciparum is the dominant species in the study area followed by P. vivax. Enhancing malaria detection and speciation skill of laboratory personnel and scaling up malaria control and prevention activities are very crucial to significantly reduce the burden of malaria in the study area.

Microclimate variables of the ambient environment deliver the actual estimates of the extrinsic incubation period of Plasmodium vivax and Plasmodium falciparum: a study from a malaria-endemic urban setting, Chennai in India

Background

Environmental factors such as temperature, relative humidity and their daily variation influence a range of mosquito life history traits and hence, malaria transmission. The standard way of characterizing environmental factors with meteorological station data need not be the actual microclimates experienced by mosquitoes within local transmission settings.

Methods

A year-long study was conducted in Chennai, India to characterize local temperature and relative humidity (RH). Data loggers (Hobos) were placed in a range of probable indoor and outdoor resting sites of Anopheles stephensi. Recordings were taken hourly to estimate mean temperature and RH, together with daily temperature range (DTR) and daily relative humidity range. The temperature data were used to explore the predicted variation in extrinsic incubation period (EIP) of Plasmodium falciparum and Plasmodium vivax between microhabitats and across the year.

Results

Mean daily temperatures within the indoor settings were significantly warmer than those recorded outdoors. DTR in indoor environments was observed to be modest and ranged from 2 to 6 °C. Differences in EIP between microhabitats were most notable during the hottest summer months of April–June, with parasite development predicted to be impaired for tiled houses and overhead tanks. Overall, the prevailing warm and stable conditions suggest rapid parasite development rate regardless of where mosquitoes might rest. Taking account of seasonal and local environmental variation, the predicted EIP of P. falciparum varied from a minimum of 9.1 days to a maximum of 15.3 days, while the EIP of P. vivax varied from 8.0 to 24.3 days.

Conclusions

This study provides a detailed picture of the actual microclimates experienced by mosquitoes in an urban slum malaria setting. The data indicate differences between microhabitats that could impact mosquito and parasite life history traits. The predicted effects for EIP are often relatively subtle, but variation between minimum and maximum EIPs can play a role in disease transmission, depending on the time of year and where mosquitoes rest. Appropriate characterization of the local microclimate conditions would be the key to fully understand the effects of environment on local transmission ecology.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2342-1) contains supplementary material, which is available to authorized users.

Multiplicity and molecular epidemiology of Plasmodium vivax and Plasmodium falciparum infections in East Africa

Background

Parasite genetic diversity and multiplicity of infection (MOI) affect clinical outcomes, response to drug treatment and naturally-acquired or vaccine-induced immunity. Traditional methods often underestimate the frequency and diversity of multiclonal infections due to technical sensitivity and specificity. Next-generation sequencing techniques provide a novel opportunity to study complexity of parasite populations and molecular epidemiology.

Methods

Symptomatic and asymptomatic Plasmodium vivax samples were collected from health centres/hospitals and schools, respectively, from 2011 to 2015 in Ethiopia. Similarly, both symptomatic and asymptomatic Plasmodium falciparum samples were collected, respectively, from hospitals and schools in 2005 and 2015 in Kenya. Finger-pricked blood samples were collected and dried on filter paper. Long amplicon (> 400 bp) deep sequencing of merozoite surface protein 1 (msp1) gene was conducted to determine multiplicity and molecular epidemiology of P. vivax and P. falciparum infections. The results were compared with those based on short amplicon (117 bp) deep sequencing.

Results

A total of 139 P. vivax and 222 P. falciparum samples were pyro-sequenced for pvmsp1 and pfmsp1, yielding a total of 21 P. vivax and 99 P. falciparum predominant haplotypes. The average MOI for P. vivax and P. falciparum were 2.16 and 2.68, respectively, which were significantly higher than that of microsatellite markers and short amplicon (117 bp) deep sequencing. Multiclonal infections were detected in 62.2% of the samples for P. vivax and 74.8% of the samples for P. falciparum. Four out of the five subjects with recurrent P. vivax malaria were found to be a relapse 44–65 days after clearance of parasites. No difference was observed in MOI among P. vivax patients of different symptoms, ages and genders. Similar patterns were also observed in P. falciparum except for one study site in Kenyan lowland areas with significantly higher MOI.

Conclusions

The study used a novel method to evaluate Plasmodium MOI and molecular epidemiological patterns by long amplicon ultra-deep sequencing. The complexity of infections were similar among age groups, symptoms, genders, transmission settings (spatial heterogeneity), as well as over years (pre- vs. post-scale-up interventions). This study demonstrated that long amplicon deep sequencing is a useful tool to investigate multiplicity and molecular epidemiology of Plasmodium parasite infections.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2337-y) contains supplementary material, which is available to authorized users.

Mapping and Modelling Malaria Risk Areas Using Climate, Socio-Demographic and Clinical Variables in Chimoio, Mozambique

Background: Malaria continues to be a major public health concern in Africa. Approximately 3.2 billion people worldwide are still at risk of contracting malaria, and 80% of deaths caused by malaria are concentrated in only 15 countries, most of which are in Africa. These high-burden countries have achieved a lower than average reduction of malaria incidence and mortality, and Mozambique is among these countries. Malaria eradication is therefore one of Mozambique’s main priorities. Few studies on malaria have been carried out in Chimoio, and there is no malaria map risk of the area. This map is important to identify areas at risk for application of Public Precision Health approaches. By using GIS-based spatial modelling techniques, the research goal of this article was to map and model malaria risk areas using climate, socio-demographic and clinical variables in Chimoio, Mozambique. Methods: A 30 m × 30 m Landsat image, ArcGIS 10.2 and BioclimData were used. A conceptual model for spatial problems was used to create the final risk map. The risks factors used were: the mean temperature, precipitation, altitude, slope, distance to water bodies, distance to roads, NDVI, land use and land cover, malaria prevalence and population density. Layers were created in a raster dataset. For class value comparisons between layers, numeric values were assigned to classes within each map layer, giving them the same importance. The input dataset were ranked, with different weights according to their suitability. The reclassified outputs of the data were combined. Results: Chimoio presented 96% moderate risk and 4% high-risk areas. The map showed that the central and south-west “Residential areas”, namely, Centro Hipico, Trangapsso, Bairro 5 and 1° de Maio, had a high risk of malaria, while the rest of the residential areas had a moderate risk. Conclusions: The entire Chimoio population is at risk of contracting malaria, and the precise estimation of malaria risk, therefore, has important precision public health implications and for the planning of effective control measures, such as the proper time and place to spray to combat vectors, distribution of bed nets and other control measures.

A 17-year trend analysis of malaria at Adi Arkay, north Gondar zone, Northwest Ethiopia

Background

Malaria is one of the leading causes of death worldwide. This study aimed to determine the trend of malaria among febrile patients seeking treatment over 17 year (1997–2013) at Adi Arkay, Northwest Ethiopia.

Methods

A 17-year malaria microscopy data were extracted retrospectively at Adi Arkay health centre. Time series and curve estimation analysis were used to evaluate trends in the data. Pearson’s Chi square test was also used to describe associations of variables.

Results

Over 17 years, 20,483 blood films were requested for malaria diagnosis at the health centre. Out of this, 7428 (36.1%) were microscopically confirmed malaria cases. Plasmodium falciparum, Plasmodium vivax, and their mixed infection accounted for 68.85, 28.79, and 2.34% of all malaria cases, respectively. There was a remarkable reduction of overall malaria during the 17 years. Malaria was reported in all age groups of both sexes, but its positivity rate was significantly higher in males and in the 15–24 years than their counterparts.

Conclusion

In relative terms, the overall positivity rate of malaria in the area over 17 years showed a significant reduction, but its magnitude as a public health problem is still alarming. Plasmodium falciparum played a significant role in the remarkable drop of overall malaria in the area, whereas vivax malaria remained unchanged. Therefore, control measures should continue to strengthen targeting both predominant malaria parasites in the area.

A Time Series Analysis: Weather Factors, Human Migration and Malaria Cases in Endemic Area of Purworejo, Indonesia, 2005-2014

BACKGROUND

Climatic and weather factors become important determinants of vector-borne diseases transmission like malaria. This study aimed to prove relationships between weather factors with considering human migration and previous case findings and malaria cases in endemic areas in Purworejo during 2005-2014.

METHODS

This study employed ecological time series analysis by using monthly data. The independent variables were the maximum temperature, minimum temperature, maximum humidity, minimum humidity, precipitation, human migration, and previous malaria cases, while the dependent variable was positive malaria cases. Three models of count data regression analysis i.e. Poisson model, quasi-Poisson model, and negative binomial model were applied to measure the relationship. The least Akaike Information Criteria (AIC) value was also performed to find the best model. Negative binomial regression analysis was considered as the best model.

RESULTS

The model showed that humidity (lag 2), precipitation (lag 3), precipitation (lag 12), migration (lag1) and previous malaria cases (lag 12) had a significant relationship with malaria cases.

CONCLUSION

Weather, migration and previous malaria cases factors need to be considered as prominent indicators for the increase of malaria case projection.

Spatial modelling of malaria cases associated with environmental factors in South Sumatra, Indonesia

Background

Malaria, a parasitic infection, is a life-threatening disease in South Sumatra Province, Indonesia. This study aimed to investigate the spatial association between malaria occurrence and environmental risk factors.

Methods

The number of confirmed malaria cases was analysed for the year 2013 from the routine reporting of the Provincial Health Office of South Sumatra. The cases were spread over 436 out of 1613 villages. Six potential ecological predictors of malaria cases were analysed in the different regions using ordinary least square (OLS) and geographically weighted regression (GWR). The global pattern and spatial variability of associations between malaria cases and the selected potential ecological predictors was explored.

Results

The importance of different environmental and geographic parameters for malaria was shown at global and village-level in South Sumatra, Indonesia. The independent variables altitude, distance from forest, and rainfall in global OLS were significantly associated with malaria cases. However, as shown by GWR model and in line with recent reviews, the relationship between malaria and environmental factors in South Sumatra strongly varied spatially in different regions.

Conclusions

A more in-depth understanding of local ecological factors influencing malaria disease as shown in present study may not only be useful for developing sustainable regional malaria control programmes, but can also benefit malaria elimination efforts at village level.

Malaria increased the risk of stunting and wasting among young children in Ethiopia: Results of a cohort study

INTRODUCTION

Given the high prevalence of malnutrition in a malaria-endemic setting, improving nutritional status could serve as a tool to prevent malaria. However, the relationship between the two conditions remains unclear. Therefore, this study assessed the association between under-nutrition and malaria among a cohort of children aged 6 to 59 months old.

METHODS

Two cohorts of children were followed for 89 weeks in a rural Rift Valley area of Ethiopia. In the first approach (malaria-malnutrition), a cohort of 2,330 non-stunted and 4,204 non-wasted children were included to assess under-nutrition (outcome) based on their previous malaria status (exposure). In the second approach (malnutrition-malaria), a cohort of 4,468 children were followed-up to measure malaria (outcome), taking under-nutrition as an exposure. A weekly home visit was carried out to identify malaria cases. Four anthropometry surveys were conducted, and generalized estimating equation (GEE) method was used to measure the association between undernutrition and malaria.

RESULTS

The prevalence of stunting was 44.9% in December 2014, 51.5% in August 2015, 50.7% in December 2015 and 48.1% in August 2016. We observed 103 cases with 118 episodes of malaria, 684 new stunting and 239 new wasting cases. The incidence rate per 10,000 weeks of observation was 3.8 for malaria, 50.4 for stunting and 8.2 for wasting. Children with malaria infection, [Adjusted Odds Ratio (AOR) = 1.9; 95% Confidence Interval (CI), 1.2-2.9)] and younger age (AOR = 1.3; 95% CI, 1.1-1.5) were more likely to be stunted. Furthermore, children with malaria infection (AOR = 8.5; 95% CI, 5.0-14.5) and young age group (AOR = 1.6; 95% CI, 1.2-2.1) were more likely to be wasted. However, stunting and wasting were not risk factors of subsequent malaria illness.

CONCLUSIONS

Malaria infection was a risk factor for stunting and wasting, but stunting or wasting was not associated with subsequent malaria illness. As our study shows that malaria is a risk factor for stunting and wasting, a close follow-up of the nutritional status of such children may be needed.

TRIAL REGISTRATION

PACT R2014 11000 882128 (8 September 2014).

Glucose-6-Phosphate Dehydrogenase Deficiency Genetic Variants in Malaria Patients in Southwestern Ethiopia

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked erythrocyte enzyme disorder with relevance to malaria treatment policy. Treatment with the antimalarial primaquine can result in hemolytic anemia in G6PD-deficient patients. With increased interest in primaquine use, it is important to identify G6PD variants in Ethiopia to inform malaria treatment policy. In the present study, mutations in the G6PD gene are identified in a sample of patients with malaria in Jimma town in southwest Ethiopia. Plasmodium species of infection were confirmed using polymerase chain reaction (PCR) and gel electrophoresis. PCR and Sanger sequencing were performed to observe a portion of the G6PD gene where the common G6PD mutations (A376G, G202A, and C563T) are found. Molecular analysis revealed that most of the samples were single Plasmodium vivax infections (83.7%). For G6PD genotyping, A376G was detected in 23.26% of individuals, whereas G202A and C563T were absent. Three other uncommon mutations were identified: rs782669677 (535G→A), rs370658483, (485 + 37 G→T), and a new mutation at chrX:154535443(C→T). Bioinformatic analysis of these mutations' potential functional impact suggests minimal effect on protein function. The discovery of both common and uncommon G6PD mutations contributes to the discussion on G6PD deficiency and appropriate primaquine treatment in Ethiopia.

Climatic Variables and Malaria Morbidity in Mutale Local Municipality, South Africa: A 19-Year Data Analysis

The north-eastern parts of South Africa, comprising the Limpopo Province, have recorded a sudden rise in the rate of malaria morbidity and mortality in the 2017 malaria season. The epidemiological profiles of malaria, as well as other vector-borne diseases, are strongly associated with climate and environmental conditions. A retrospective understanding of the relationship between climate and the occurrence of malaria may provide insight into the dynamics of the disease’s transmission and its persistence in the north-eastern region. In this paper, the association between climatic variables and the occurrence of malaria was studied in the Mutale local municipality in South Africa over a period of 19-year. Time series analysis was conducted on monthly climatic variables and monthly malaria cases in the Mutale municipality for the period of 1998–2017. Spearman correlation analysis was performed and the Seasonal Autoregressive Integrated Moving Average (SARIMA) model was developed. Microsoft Excel was used for data cleaning, and statistical software R was used to analyse the data and develop the model. Results show that both climatic variables’ and malaria cases’ time series exhibited seasonal patterns, showing a number of peaks and fluctuations. Spearman correlation analysis indicated that monthly total rainfall, mean minimum temperature, mean maximum temperature, mean average temperature, and mean relative humidity were significantly and positively correlated with monthly malaria cases in the study area. Regression analysis showed that monthly total rainfall and monthly mean minimum temperature (R² = 0.65), at a two-month lagged effect, are the most significant climatic predictors of malaria transmission in Mutale local municipality. A SARIMA (2,1,2) (1,1,1) model fitted with only malaria cases has a prediction performance of about 51%, and the SARIMAX (2,1,2) (1,1,1) model with climatic variables as exogenous factors has a prediction performance of about 72% in malaria cases. The model gives a close comparison between the predicted and observed number of malaria cases, hence indicating that the model provides an acceptable fit to predict the number of malaria cases in the municipality. To sum up, the association between the climatic variables and malaria cases provides clues to better understand the dynamics of malaria transmission. The lagged effect detected in this study can help in adequate planning for malaria intervention.

Sanitation, hookworm, anemia, stunting, and wasting in primary school children in southern Ethiopia: Baseline results from a study in 30 schools

Background

Inadequate nutrition; neglected topical diseases; and insufficient water, sanitation, and hygiene (WASH) are interrelated problems in schools in low-income countries, but are not routinely tackled together. A recent three-year longitudinal study investigated integrated school health and nutrition approaches in 30 government primary schools in southern Ethiopia. Here, we report on baseline associations between sanitation, hookworm infection, anemia, stunting, and wasting.

Methods

In each school, the Schistosoma mansoni, S. haematobium, and soil-transmitted helminth infection intensities; blood hemoglobin concentrations; heights; and weights of approximately 125 students were assessed. Of these 125 students, approximately 20 were randomly selected for student WASH surveys. Of these 20, approximately 15 were randomly selected for household sanitation observations. School WASH was also assessed through a combination of observations and questions to the headteacher. Mixed-effects logistic regression was used to compare household sanitation with hookworm infection (the other parasites being much less prevalent); and hookworm infection with anemia, stunting, and wasting.

Findings

Blood, stool, and urine samples were provided by 3,729 children, and student WASH and household WASH surveys were conducted with 596 and 448 of these students, respectively.

Hookworm, Ascaris lumbricoides, Trichuris trichiura, and S. mansoni infections had prevalences of 18%, 4.8%, 0.6%, and 0.3%, respectively, and no S. haematobium infections were found. Anemia, stunting, and wasting had prevalences of 23%, 28%, and 14%, respectively.

No statistically significant associations were found between latrine absence or evidence of open defecation at home, and hookworm infection (adjusted odds ratio, OR = 1.28, 95% confidence interval, CI: 0.476–3.44; and adjusted OR = 1.21, 95% CI: 0.468–3.12; respectively); or between hookworm infection and anemia, stunting, or wasting (adjusted OR = 1.24, 95% CI: 0.988–1.57; adjusted OR = 0.992, 95% CI: 0.789–1.25; and adjusted OR = 0.969, 95% CI: 0.722–1.30; respectively).

Conclusions

In this setting, no statistically significant associations were found between sanitation and hookworm; or between hookworm and anemia, stunting, or wasting. More evidence on best practices for integrated school health interventions will be gathered from the follow-up surveys in this study.

It is thought that inadequate sanitation may exacerbate hookworm transmission, and that hookworm infection may give rise to health problems including anemia, stunting, and wasting. Integrating monitoring of, and interventions against, these problems may yield significant cost savings. Such integrated interventions should be guided by both evidence of the relationships between the various health problems, and examples of optimally effective integration. Here, we present baseline findings from a three-year longitudinal study investigating combined school feeding; school water, sanitation, and hygiene (WASH); and deworming interventions in 30 primary schools in southern Ethiopia. In particular, we compare household sanitation, hookworm infection, and anemia, stunting, and wasting, in the schoolchildren. None of these associations were found to be statistically significant (although hookworm infection was associated with borderline statistically significantly higher odds of anemia; P = 0.06). The lack of significant associations may be due to the low intensities of the hookworm infections in this setting, poor conditions of latrines reducing their impact on hookworm transmission, and other factors such as malaria and inadequate diet causing anemia, stunting, and wasting.

A climate-based malaria model with the use of bed nets

Insecticide-treated bed nets (ITNs) are among the most important and effective intervention measures against malaria. In order to investigate the impact of bed net use on disease control, we formulate a periodic vector-bias malaria model incorporating the juvenile stage of mosquitoes and the use of ITNs. We derive the vector reproduction ratio [Formula: see text] and the basic reproduction ratio [Formula: see text]. We show that the global dynamics of the model is completely determined by these two reproduction ratios. More precisely, the mosquito-free periodic solution is globally attractive if [Formula: see text]; the unique disease-free periodic solution is globally attractive if [Formula: see text] and [Formula: see text]; and the model admits a unique positive periodic solution and it is globally attractive if [Formula: see text] and [Formula: see text]. Numerically, we study the malaria transmission case in Port Harcourt, Nigeria. Our findings show that the use of ITNs has a positive effect on reducing [Formula: see text], and that malaria may be eliminated from this area if over 75% of the human population were to use ITNs. The simulation about the long term behavior of solutions has good agreement with the obtained analytic result. Moreover, we find that the ignorance of the vector-bias effect may result in underestimation of the basic reproduction ratio [Formula: see text]. Another notable result is that the infection risk would be underestimated if the basic reproduction ratio [Formula: see text] of the time-averaged autonomous system were used.

Proximity to vector breeding site and risk of Plasmodium vivax infection: a prospective cohort study in rural Ethiopia

Background

Despite falling incidence and mortality since the turn of the century, malaria remains an important global health challenge. In the future fight against malaria, greater emphasis will have to be placed on understanding and addressing malaria caused by the Plasmodium vivax parasite. Unfortunately, due to years of neglect and underfunding, there are currently many gaps in knowledge of P. vivax malaria. The aims of the present study were to explore the association between distance to vector breeding site and P. vivax infection in rural Ethiopia, and, secondarily, to test whether this association varies with age.

Methods

A prospective, cohort study of all residents in the Chano Mille Kebele in southern Ethiopia from April 2009 to March 2011 (n = 8121). Weekly household follow up visits included screening for febrile cases (active surveillance). Participants were also asked to contact the local health centre if they experienced subjective fever between visits (passive surveillance). Plasmodium vivax infection was confirmed using microscopy by two independent readers. Information was collected on demographics and household characteristics including GPS-determined distance to vector breeding site. Data was analysed using Cox regression modelling.

Results

Overall the P. vivax infection rate was 12.3/1000 person-years (95% CI 10.5–14.5). Mean household distance to breeding site was 2449 m (range 1646–3717 m). Fully adjusted results showed very strong evidence of an association between proximity to breeding site and P. vivax infection: rate ratio = 3.47 (95% CI 2.15–5.60; P < 0.001) comparing the group closest to the breeding site (distance < 2100 m; n = 1383) to the group furthest away (distance > 2700 m; n = 2460). There was no evidence that age was an effect modifier in the association.

Conclusion

Results showed strong evidence that household proximity to vector breeding site is positively associated with P. vivax infection in rural Ethiopia, and that this association is constant across age groups. The findings might influence how net-distribution and indoor residual spraying campaigns are planned, help guide strategies on water resource development by highlighting potential health effects of man-made dams near human habitats, and add to current educational information given to people living close to breeding sites.

Prevalence and associated risk factors of malaria among adults in East Shewa Zone of Oromia Regional State, Ethiopia: a cross-sectional study

Background

Malaria is one of the most important causes of morbidity and mortality in sub-Saharan Africa. The disease is prevalent in over 75% of the country’s area making it the leading public health problems in the country. Information on the prevalence of malaria and its associated factors is vital to focus and improve malaria interventions.

Methods

A cross-sectional study was carried out from October to November 2012 in East Shewa zone of Oromia Regional State, Ethiopia. Adults aged 16 or more years with suspected malaria attending five health centers were eligible for the study. Logistic regression models were used to examine the effect of each independent variable on risk of subsequent diagnosis of malaria.

Results

Of 810 suspected adult malaria patients who participated in the study, 204 (25%) had microscopically confirmed malaria parasites. The dominant Plasmodium species were P. vivax (54%) and P. falciparum (45%), with mixed infection of both species in one patient. A positive microscopic result was significantly associated with being in the age group of 16 to 24 years [Adjusted Odds Ratio aOR 6.7; 95% CI: 2.3 to 19.5], 25 to 34 years [aOR 4.2; 95% CI: 1.4 to 12.4], and 35 to 44 years [aOR 3.7; 95% CI: 1.2–11.4] compared to 45 years or older; being treated at Meki health center [aOR 4.1; 95% CI: 2.4 to 7.1], being in Shashemene health center [aOR = 2.3; 95% CI: 1.5 to 4.5], and living in a rural area compared to an urban area [aOR 1.7; 95% CI: 1.1 to 2.6)].

Conclusion

Malaria is an important public health problem among adults in the study area with a predominance of P. vivax and P. falciparum infection. Thus, appropriate health interventions should be implemented to prevent and control the disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4577-0) contains supplementary material, which is available to authorized users.

Modelling the influence of climate on malaria occurrence in Chimoio Municipality, Mozambique

Background

Mozambique was recently ranked fifth in the African continent for the number of cases of malaria. In Chimoio municipality cases of malaria are increasing annually, contrary to the decreasing trend in Africa. As malaria transmission is influenced to a large extent by climatic conditions, modelling this relationship can provide useful insights for designing precision health measures for malaria control. There is a scarcity of information on the association between climatic variability and malaria transmission risk in Mozambique in general, and in Chimoio in particular. Therefore, the aim of this study is to model the association between climatic variables and malaria cases on a weekly basis, to help policy makers find adequate measures for malaria control and eradication.

Methods

Time series analysis was conducted using data on weekly climatic variables and weekly malaria cases (counts) in Chimoio municipality, from 2006 to 2014. All data were analysed using SPSS-20, R 3.3.2 and BioEstat 5.0. Cross-correlation analysis, linear processes, namely ARIMA models and regression modelling, were used to develop the final model.

Results

Between 2006 and 2014, 490,561 cases of malaria were recorded in Chimoio. Both malaria and climatic data exhibit weekly and yearly systematic fluctuations. Cross-correlation analysis showed that mean temperature and precipitation present significantly lagged correlations with malaria cases. An ARIMA model (2,1,0) (2,1,1)₅₂, and a regression model for a Box-Cox transformed number of malaria cases with lags 1, 2 and 3 of weekly malaria cases and lags 6 and 7 of weekly mean temperature and lags 12 of precipitation were fitted. Although, both produced similar widths for prediction intervals, the last was able to anticipate malaria outbreak more accurately.

Conclusion

The Chimoio climate seems ideal for malaria occurrence. Malaria occurrence peaks during January to March in Chimoio. As the lag effect between climatic events and malaria occurrence is important for the prediction of malaria cases, this can be used for designing public precision health measures. The model can be used for planning specific measures for Chimoio municipality. Prospective and multidisciplinary research involving researchers from different fields is welcomed to improve the effect of climatic factors and other factors in malaria cases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2205-6) contains supplementary material, which is available to authorized users.

Household level spatio-temporal analysis of Plasmodium falciparum and Plasmodium vivax malaria in Ethiopia

BACKGROUND

The global decline of malaria burden and goals for elimination has led to an increased interest in the fine-scale epidemiology of malaria. Micro-geographic heterogeneity of malaria infection could have implications for designing targeted small-area interventions.

METHODS

Two-year longitudinal cohort study data were used to explore the spatial and spatio-temporal distribution of malaria episodes in 2040 children aged < 10 years in 16 villages near the Gilgel-Gibe hydropower dam in Southwest Ethiopia. All selected households (HHs) were geo-referenced, and children were followed up through weekly house-to-house visits for two consecutive years to identify febrile episodes of P. falciparum and P. vivax infections. After confirming the spatial dependence of malaria episodes with Ripley's K function, SatScan^TM was used to identify purely spatial and space-time clusters (hotspots) of annual malaria incidence for 2 years follow-up: year 1 (July 2008-June 2009) and year 2 (July 2009-June 2010).

RESULTS

In total, 685 P. falciparum episodes (in 492 HHs) and 385 P. vivax episodes (in 290 HHs) were identified, representing respectively incidence rates of 14.6 (95% CI: 13.4-15.6) and 8.2 (95% CI: 7.3-9.1) per 1000 child-months at risk. In year 1, the most likely (128 HHs with 63 episodes, RR = 2.1) and secondary (15 HHs with 12 episodes, RR = 5.31) clusters of P. vivax incidence were found respectively in southern and north-western villages; while in year 2, the most likely cluster was located only in north-western villages (85 HHs with 16 episodes, RR = 4.4). Instead, most likely spatial clusters of P. falciparum incidence were consistently located in villages south of the dam in both years: year 1 (167 HHs with 81 episodes, RR = 1.8) and year 2 (133 HHs with 67 episodes, RR = 2.2). Space-time clusters in southern villages for P. vivax were found in August-November 2008 in year 1 and between November 2009 and February 2010 in year 2; while for P. falciparum, they were found in September-November 2008 in year 1 and October-November 2009 in year 2.

CONCLUSION

Hotspots of P. falciparum incidence in children were more stable at the geographical level and over time compared to those of P. vivax incidence during the study period.

The assessment and the farmers' perceived ranking of feed resources and coping strategies with feed scarcity in smallholder dairy farming in selected district towns of Jimma Zone, Ethiopia

Inadequate quantity and quality of feed resources are major constraints limiting milk production and reproductive performance of dairy cattle in Ethiopia. The aim of this study was to assess dairy cattle feed resources, feeding practices, the farmers' perceived ranking of feed resources, causes of feed shortage, and coping strategies to feed scarcity in smallholder dairy system in selected district towns of Jimma Zone, Ethiopia. Data were obtained by interviewing 52 randomly selected smallholder dairy farmers using structured questionnaires and through direct observations. Results showed that 20 main feed types used by dairy farmers were identified and categorized into natural pastures, crop residues, green feeds, hay, agro-industrial by-products, concentrate mix, and non-conventional feeds. Overall, natural pasture (mean rank = 0.453), non-conventional feeds (0.307), cut green feeds (0.086), conserved hay (0.076), crop residues (0.049), and concentrate feeds (0.029) were ranked as the main feed resources in decreasing order of importance. Natural pasture grazing (92.2% of the respondents), hay (35.6%), and green feeds (29.4%) were the most important conventional basal feeds used. Wheat bran (11.7% of the respondents) followed by commercial concentrate mix (9.4%), Noug seedcake (8.3%), grain (7.8%), and molasses (6.1%) were the concentrate supplements used. Overall, bulule-flour mill leftovers (67.2% of the farmers), bean and pea hulls (57.2%) and atella-local brew by-product (37.2%), enset (Ensete ventricosum, 34.4%), and sugarcane top (32.2%) were the non-conventional feeds available and used during feed scarcity. Barley and teff (Eragrostis teff) straws and maize and sorghum stovers were the main crop residues used in the dry seasons. Overall, 73.9, 12.2, 12.2, and 1.7% of the respondents practiced free grazing, zero grazing, semi-zero, and a combination of zero- and free-grazing systems, respectively. Over 84% of the respondents in the dry season and 50% in the wet season reported experiencing a shortage of feeds. Poor feed availability (73.9% of the respondents) was reported as the main causes of feed shortage followed by shortage of pastureland (7.8%). Increased use of bulule (55.6% of the respondents), crop residues (16.1%), non-conventional feed resources (14.4%), conserved hay (11.1%), purchased green feeds and concentrates (1.1%), and reducing herd size (1.1%) were the farmers' adopted coping strategies to mitigate feed shortage. It is suggested that technical intervention to improve the quality and efficient utilization of the existing feed resources is crucial to enable sustainable feed supply and boost milk production. Technologies that are easy to adopt, feasible, and low cost are also needed to be developed in participatory manner.

Assessing the Risk Factors Associated with Malaria in the Highlands of Ethiopia: What Do We Need to Know?

Malaria has been Ethiopia's predominant communicable disease for decades. Following the catastrophic malaria outbreak in 2003⁻2004, the Federal Ministry of Health (FMoH) took drastic public health actions to lower the burden of malaria. The FMoH achieved significant declines in malaria mortality and incidence, and recently declared its objective to achieve malaria elimination in low malaria transmission areas of Ethiopia by 2020. However, while the overall malaria prevalence has decreased, unpredictable outbreaks increasingly occur irregularly in regions previously considered "malaria-free". Such outbreaks have disastrous consequences on populations of these regions as they have no immunity against malaria. The Amhara Region accounts for 31% of Ethiopia's malaria burden and is targeted for malaria elimination by the FMoH. Amhara's epidemiological surveillance system faces many challenges to detect in a timely manner the unpredictable and irregular malaria outbreaks that occur in areas of otherwise low transmission. Despite the evidence of a shift in malaria transmission patterns, Amhara's malaria control interventions remain constrained to areas that are historically known to have stable malaria transmission. This paper discusses the influence of temperature and precipitation variability, entomological parameters, and human population mobility on malaria transmission patterns across the Amhara Region, and in particular, in areas of unstable transmission. We argue that malaria epidemiological surveillance systems can be improved by accounting for population movements in addition to environmental and entomological factors. However, to date, no study has statistically analyzed the interplay of population dynamics on environmental and entomological drivers of malaria transmission.

A Weather-Based Prediction Model of Malaria Prevalence in Amenfi West District, Ghana

This study investigated the effects of climatic variables, particularly, rainfall and temperature, on malaria incidence using time series analysis. Our preliminary analysis revealed that malaria incidence in the study area decreased at about 0.35% annually. Also, the month of November recorded approximately 21% more malaria cases than the other months while September had a decreased effect of about 14%. The forecast model developed for this investigation indicated that mean minimum (P = 0.01928) and maximum (P = 0.00321) monthly temperatures lagged at three months were significant predictors of malaria incidence while rainfall was not. Diagnostic tests using Ljung-Box and ARCH-LM tests revealed that the model developed was adequate for forecasting. Forecast values for 2016 to 2020 generated by our model suggest a possible future decline in malaria incidence. This goes to suggest that intervention strategies put in place by some nongovernmental and governmental agencies to combat the disease are effective and thus should be encouraged and routinely monitored to yield more desirable outcomes.

Prevalence of malaria and associated factors in Benna Tsemay district of pastoralist community, Southern Ethiopia

BACKGROUND

Though the burden of malaria is declining, challenges in control continue globally, regionally and nationally as the transmission of malaria is dynamic and determinants differ by place and time, and across populations. The current level of knowledge on malaria prevalence and associated factors in specific communities, such as pastoralist communities of Ethiopia, is lacking.

METHODS

A community based cross-sectional survey was conducted among pastoralist communities from December 2011 to January 2012. Background information and peripheral blood samples were collected from 461 randomly selected study participants. Multivariate regression analysis was done to explore the risk factors associated to malaria.

RESULT

The prevalence of malaria among 461 examined study participants was 6.1 % (95 % CI = 4.2, 8.5). The infection rate with Plasmodium falciparum and Plasmodium vivax was 64.3 % (95 % CI = 45.5, 80.2) and 21.4 % (95 % CI = 19.8, 54.5), respectively, while mixed infection was 14.3 % (95 % CI = 4.7, 30.9). The infection rate was higher among lactating (22.2 %, 95 % CI =7.5, 45.3) and pregnant (17.6 %, 95 % CI = 4.7, 40.9) women compared with other community groups like infants (12 %). Mosquito net coverage of the study population was 90.1 % with an average of 1.8 per household. Traditional practices related to malaria prevention and treatment were not significantly associated with malaria infection (p > 0.05). Pregnancy (adjusted Odds Ratio [AOR]: 12.6, 95 % CI = 1.7, 94.7) and saving mosquito net for later use (AOR 9.6: 95 % CI = 2.2, 42.8) were independently associated with prevalent malaria infection.

CONCLUSION

In spite of high coverage of mosquito nets, prevalence of malaria in this pastoralist community was high, affecting pregnant and lactating women at a higher rate. Pregnancy and saving mosquito nets for later use were identified as the associated risk factors. Health education on prevalence of malaria and knowledge on risk factors might be able to change the health behavior in this pastoralist community which consequently can decrease the malaria morbidity and mortality.

TRIAL REGISTRATION

ISRCTN ISRCTN73824458, Registered 28 September 2014.

Ascarid infestation in captive Siberian tigers in China

The Siberian tiger is endangered and is listed by the International Union for the Conservation of Nature; the captive environment is utilized to maintain Siberian tiger numbers. Little information regarding the prevalence of parasites in Siberian tigers is available. A total of 277 fecal samples of Siberian tigers were analyzed in this study. The microscopic analysis indicated the presence of ascarid eggs of Toxascaris leonina and Toxocara cati. The ascarid infection rate was 67.5% in Siberian tigers. The internal transcribed spacer-1 (ITS-1) phylogenetic analysis indicated that T. leonina belonged to Toxascaris and that Toxo. cati belonged to Toxocara. The infestation rate and intensity of T. leonina were higher than those of Toxo. cati. One-way analysis of variance showed that the presence of T. leonina was significantly associated with age (P<0.05). Temperature changes also influenced T. leonina and Toxo. cati infestation, and a rise in temperature caused an increase in the number of T. leonina and Toxo. cati eggs. This study provides a better understanding of ascarid infestation among the captive Siberian tigers and is helpful for the prevention of the spread of infectious parasitic diseases among other tigers in the zoo.

Vector Potential of Blattella germanica (L.) (Dictyoptera: Blattidae) for Medically Important Bacteria at Food Handling Establishments in Jimma Town, Southwest Ethiopia

Cockroaches have been regarded as possible vectors of human enteropathogens. Their presence and crawl particularly in food handling establishments could be risky for human health. Therefore, this study was done to determine the vector potential of cockroach for medically important bacterial pathogens in restaurants and cafeterias. A cross-sectional study was conducted on cockroaches from restaurants and cafeterias in Jimma town from May to September 2014. Standard taxonomic keys and microbiological techniques were applied for species identification and isolation. Data was analyzed in SPSS version 16.0. All cockroaches trapped were the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattidae). Escherichia coli was the most frequently isolated followed by Salmonella species (serogroups B, D, E, C₁, and NG), Bacillus cereus, and Shigella flexneri. Wide varieties of bacteria of medical relevance were also identified. Of which, Klebsiella spp. 49(40.8%), Bacillus spp., and Staphylococcus saprophyticus were predominant. Blattella germanica (L.) (Dictyoptera: Blattidae) could serve as a potential vector for the dissemination of foodborne pathogens such as Salmonella spp., Shigella flexneri, E. coli, S. aureus, and B. cereus and these bacteria could be a major threat to public health. Therefore, environmental sanitation and standard hygiene need to be applied in the food handling establishments in that locality.

High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control

In Zimbabwe, more than half of malaria cases are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. The objectives of this study were to develop a prediction model based on environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province. From October 2012 to September 2015, 483 households were surveyed, and 104 individuals residing within 69 households had positive rapid diagnostic test results. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates extracted from high-resolution remote sensing data sources. Model predictions and prediction standard errors were generated for the rainy and dry seasons. The resulting maps predicted elevated risk during the rainy season, particularly in low-lying areas bordering Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria risk scattered along the northern and western peripheries of the study area. These findings underscore the need for strong cross-border malaria control initiatives to complement country-specific interventions.

Ape malaria transmission and potential for ape-to-human transfers in Africa

Recent studies have highlighted the large diversity of malaria parasites infecting African great apes (subgenus Laverania) and their strong host specificity. Although the existence of genetic incompatibilities preventing the cross-species transfer may explain host specificity, the existence of vectors with a high preference for a determined host represents another possibility. To test this hypothesis, we undertook a 15-mo-long longitudinal entomological survey in two forest regions of Gabon, where wild apes live, at different heights under the canopy. More than 2,400 anopheline mosquitoes belonging to 18 species were collected. Among them, only three species of Anopheles were found infected with ape Plasmodium: Anopheles vinckei, Anopheles moucheti, and Anopheles marshallii Their role in transmission was confirmed by the detection of the parasites in their salivary glands. Among these species, An. vinckei showed significantly the highest prevalence of infection and was shown to be able to transmit parasites of both chimpanzees and gorillas. Transmission was also shown to be conditioned by seasonal factors and by the heights of capture under the canopy. Moreover, human landing catches of sylvan Anopheles demonstrated the propensity of these three vector species to feed on humans when available. Our results suggest therefore that the strong host specificity observed in the Laveranias is not linked to a specific association between the vertebrate host and the vector species and highlight the potential role of these vectors as bridge between apes and humans.

Severe Malaria Associated with Plasmodium falciparum and P. vivax among Children in Pawe Hospital, Northwest Ethiopia

Despite rigorous effort made to control malaria for more than a century, it is still among the main public health problems in least developed regions of the world. Majority of deaths associated with malaria occur in sub-Sahara Africa among biologically risked groups. Thus, this study was designed to assess the incidence of severe malaria syndromes among children in Pawe Hospital, Northwest Ethiopia. Children seeking medication for malaria infection in Pawe Hospital during the study period were recruited. Sociodemographic characteristics, physical, hematological, and clinical features of complicated malaria were assessed following standard parasitological and clinical procedures. A total of 263 children were found malaria positive. Among these, 200 were infected with Plasmodium falciparum. Most of the severe malaria symptoms were observed among children infected with P. falciparum and P. vivax. The study showed that significant number of the children developed severe life threatening malaria complications. This calls for prompt early diagnosis and effective treatment of patients to reduce mortality and complications associated with malaria in the study site.

Insecticide treated nets use and its determinants among settlers of Southwest Ethiopia

Background

Ethiopia is rapidly increasing insecticide-treated nets (ITNs) coverage to combat malaria, but adequate follow-up and factors affecting use of ITNs is lacking. The aim of this study was to assess determinants of the use of ITNs in a southwest area of Ethiopia.

Methods

This cross-sectional survey was conducted in the Chewaka district settlement area of southwest Oromia from March to May, 2013. Kebeles were stratified by degree of urbanization (rural, peri-urban, or urban). Randomly selected households, which had been freely supplied with at least one ITN, were surveyed using a pre-tested, structured questionnaire administered through household interviews. Logistic regression analysis was used to examine the association between use of ITNs and determinant factors.

Results

Of 574 households surveyed, 72.6 % possessed ITNs and 80 % of these had been used the night before the survey. The most common reasons for the absence ITNs in the household identified in this study were ITNs were old and therefore discarded and that households use ITNs for purposes other than their intended use. The multivariate analysis found that knowledge of malaria transmission by mosquito bites (Adjusted OR = 3.44, 95 % CI: 1.80–6.59), and washing of ITNs at least once by households (Adjusted OR = 2.66, 95 % CI: 1.35–5.26) were significantly associated with an ITN being used by households. The mean possession was 1.59 ITN per household (3.57 persons per an ITN). One hundred fifty four (36.9 %) of ITNs had at least one hole/tear. Among these, 108 (70.1 %) ITNs had at least one hole/tear with greater than 2 cm and 29 (18.8 %) had greater than seven holes/tears.

Conclusions

This study in Southwest Ethiopia showed a high proportion of net ownership compared to a household survey from Ethiopia which included in the World Malaria Report. Despite somewhat high percentages ITN ownership, the study demonstrated there was still a gap between ownership and use of ITNs. Use of ITNs was affected by knowledge of malaria transmission by mosquito bite and washing of ITNs at least once by households. Intensive health education and community mobilization efforts should be employed to attempt to influence these factors that significantly affect ITN use.

Review of Climate Change and Health in Ethiopia: Status and Gap Analysis

BACKGROUND

This review assessed Ethiopia's existing situation on issues related to the environment, climate change and health, and identifies gaps and needs that can be addressed through research, training, and capacity building.

METHODS

The research was conducted through a comprehensive review of available secondary data and interviewing key informants in various national organizations involved in climate change adaptation and mitigation activities.

RESULTS

Climate change-related health problems, such as mortality and morbidity due to floods and heat waves, vector-borne diseases, water-borne diseases, meningitis, and air pollution-related respiratory diseases are increasing in Ethiopia. Sensitive systems such as agriculture, health, and water have been affected, and the effects of climate change will continue to magnify without the right adaptation and mitigation measures. Currently, research on climate change and health is not adequately developed in Ethiopia. Research and other activities appear to be fragmented and uncoordinated. As a result, very few spatially detailed and methodologically consistent studies have been made to assess the impact of climate in the country. There has often been a lack of sufficient collaboration among organizations on the planning and execution of climate change and health activities, and the lack of trained professionals who can perform climate change and health-related research activities at various levels.

CONCLUSION

Firstly, there is a lack of organized structure in the various organizations. Secondly, there is inadequate level of inter-sectoral collaboration and poor coordination and communication among different stakeholders. Thirdly, there are no reliable policy guidelines and programs among organizations, agencies and offices that target climate change and health. Fourth, the existing policies fail to consider the gender and community-related dimensions of climate change. Fifth, the monitoring and evaluation efforts exerted on climate change and health activities are not strong enough to address the climate change and health issues in the country.

Diagnostic performance of rapid diagnostic tests for the diagnosis of malaria at public health facilities in north-west Ethiopia

OBJECTIVE

To assess the performance of RDTs against nested polymerase chain reaction (nPCR) for the diagnosis of malaria in public health facilities in north-western Ethiopia.

METHODS

Cross-sectional study at public health facilities in North Gondar, Ethiopia, of 359 febrile patients with signs and symptoms consistent with malaria. Finger prick blood samples were collected for testing in a P. falciparum/pan-malaria RDTs and for molecular analysis. Sensitivity, specificity and predictive values were determined for the RDTs using nPCR as reference diagnostic method. Kappa value was determined to demonstrate the consistency of the results between the diagnostic tools.

RESULTS

By RDTs, 22.28% (80/359) of patients tested positive for malaria, and by nPCR, 27.02% (97/359) did. In nPCR, 1.67% (6/359) and 0.28% (1/359) samples were positive for P. ovale and P. malariae, which had almost all tested negative in the RDTs. The sensitivity, specificity, positive and negative predictive values of RDTs for the diagnosis of malaria were 62.9%, 92.7%, 76.3% and 87.1%, respectively, with 0.589 measurement agreement between RDTs and nPCR. The sensitivity and specificity of RDTs for P. falciparum identification only were 70.8% and 95.2%, and 65.2% and 93.1% for P. vivax.

CONCLUSION

Although RDTs are commonly used at health posts in resource-limited environments, their sensitivity and specificity for the detection and species identification of Plasmodium parasites were poor compared to nPCR, suggesting caution in interpreting RDTs results. Particularly, in the light of expanded efforts to eliminate malaria in the country, more sensitive diagnostic procedures will be needed.

Sporogonic Cycles Calculated Using Degree-Days, as a Basis for Comparison of Malaria Parasite Development in Different Eco-Epidemiological Settings in India

In India, malaria transmission is prevalent across diverse geologies and ecologies. Temperature is one of the key determinants of malarial transmission, causing low endemicity in some areas than in others. Using a degree-day model, we estimated the maximum and minimum possible number of days needed to complete a malarial sporogonic cycle (SC), in addition to the possible number of SCs for Plasmodium vivax and Plasmodium falciparum under two different ecological settings with either low or high endemicity for malaria at different elevations. In Raikhalkhatta (in the Himalayan foothills) SCs were modeled as not occurring from November to February, whereas in Gandhonia village (forested hills), all but only one month were suitable for malarial SCs. A minimum of 6 days and maximum of 46 days were required for completion of one SC. Forested hilly areas were more suitable for malaria parasite development in terms of SCs (25 versus 21 for P. falciparum and 32 versus 27 for P. vivax). Degree-days also provided a climatic explanation for the current transmission of malaria at different elevations. The calculation of degree-days and possible SC has applications in the regional analysis of transmission dynamics and management of malaria in view of climate change.

Pathogen group specific risk factors for clinical mastitis, intramammary infection and blind quarters at the herd, cow and quarter level in smallholder dairy farms in Jimma, Ethiopia

A cross-sectional study on clinical mastitis, intramammary infection (IMI) and blind quarters was conducted on 50 smallholder dairy farms in Jimma, Ethiopia. A questionnaire was performed, and quarters of 211 cows were sampled and bacteriologically cultured. Risk factors at the herd, cow, and quarter level for clinical mastitis and (pathogen-specific) intramammary infection were studied using multilevel modeling. As well, factors associated with quarters being blind were studied. Eleven percent of the cows and 4% of the quarters had clinical mastitis whereas 85% of the cows and 51% of the quarters were infected. Eighteen percent of the cows had one or more blind quarter(s), whereas 6% of the quarters was blind. Non-aureus staphylococci were the most frequently isolated pathogens in both clinical mastitis cases and IMI. The odds of clinical mastitis was lower in herds where heifers were purchased in the last year [odds ratio (OR) with 95% confidence interval: 0.11 (0.01-0.90)], old cows (>4 years) [OR: 0.45 (0.18-1.14)], and quarters not showing teat injury [OR: 0.23 (0.07-0.77)]. The odds of IMI caused by any pathogen was higher in herds not practicing teat drying before milking (opposed to drying teats with 1 towel per cow) [OR: 1.68 (1.05-2.69)], cows in later lactation (>180 DIM opposed to ≤90 DIM) [OR: 1.81 (1.14-2.88)], cows with a high (>3) body condition score (BCS) [OR: 1.57 (1.06-2.31)], right quarters (opposed to a left quarter position) [OR: 1.47 (1.10-1.98)], and quarters showing teat injury [OR: 2.30 (0.97-5.43)]. Quarters of cows in herds practicing bucket-fed calf feeding (opposed to suckling) had higher odds of IMI caused by Staphylococcus aureus [OR: 6.05 (1.31-27.90)]. Except for BCS, IMI caused by non-aureus staphylococci was associated with the same risk factors as IMI caused by any pathogen. No access to feed and water immediately after milking [OR: 2.41 (1.26-4.60)], higher parity [OR: 3.60 (1.20-10.82)] and tick infestation [OR: 2.42 (1.02-5.71)] were risk factors for quarters being blind. In conclusion, replacement of old cows, prevention of teat injuries/lesions, drying teats with 1 towel per cow before milking, improving fertility in order to shorten the lactation period, allowing (restricted) suckling, access to feed and water immediately after milking, and improving tick control could improve udder health in Jimma.

In vivo antiplasmodial and toxicological effect of crude ethanol extract of Echinops kebericho traditionally used in treatment of malaria in Ethiopia

BACKGROUND

Medicinal plants have contributed significantly to current malaria treatment. Emergence of resistance to currently available drugs has necessitated the search for new plant-based anti-malarial agents and several plant-based, pharmacologically active anti-malarial compounds have been isolated. This study was conducted to validate the traditional usage of Echinops kebericho for treating malaria in the traditional health care system of Ethiopia.

METHODS

The roots of E. kebericho were collected from Masha Woreda, Sheka Zone. After collection, the plant materials were identified by a taxonomist, dried under shade and crushed to powder for extraction. The powdered roots were extracted by maceration using 70 % ethanol. Acute toxicity study of the crude extract was carried out in Swiss albino mice. The in vivo anti-malarial activity of plant extract (200, 350 and 500 mg/kg) of E. kebericho roots against a chloroquine (CQ) sensitive strain of Plasmodium berghei strain ANKA was assessed using the four-day suppressive test procedure. Parameters such as parasitaemia, packed cell volume, body weight and survival time were then determined using standard tests.

RESULTS

Oral administration of the ethanol extract showed significant (P<0.001) parasitaemia suppression at dose levels of 350 and 500 mg/kg in dose-related manner compared with the negative control. Five hundred mg/kg showed the highest (57.29±1.76 %) parasitaemia suppression. The survival times of P. berghei-infected mice were also increased in a dose-dependent manner but the test material did not prevent weight loss associated with increased parasitaemia. The result also showed the plant material prevented the loss in packed cell volume associated with increased parasitaemia. Its oral LD50 was found to be greater than 5,000 mg/kg, indicating its wider safety margin in mice.

CONCLUSION

The result revealed the ethanol extract of E. kebericho roots has anti-malarial activity against P. berghei in an animal model and lends support to the use of the plant to combat malaria in Ethiopian folk medicine. Further work is necessary to isolate, identify and characterize the active principles from the plant material.

Prevalence and predictors of asymptomatic malaria parasitemia among pregnant women in the rural surroundings of Arbaminch Town, South Ethiopia

Background

In Sub-Saharan African countries, including Ethiopia, malaria in pregnancy is a major public health threat which results in significant morbidities and mortalities among pregnant women and their fetuses. In malaria endemic areas, Plasmodium infections tend to remain asymptomatic yet causing significant problems like maternal anemia, low birth weight, premature births, and still birth. This study was conducted to determine the prevalence and predictors of asymptomatic Plasmodium infection among pregnant women in the rural surroundings of Arba Minch Town, Southern Ethiopia.

Methods

A community based cross-sectional study comprising multistage sampling was conducted between April and June, 2013. Socio-demographic data were collected by using a semi-structured questionnaire. Plasmodium infection was diagnosed by using Giemsa-stained blood smear microscopy and a rapid diagnostic test (SD BIOLINE Malaria Ag Pf/Pv POCT, standard diagnostics, inc., Korea).

Results

Of the total 341 pregnant women participated in this study, 9.1% (31/341) and 9.7% (33/341) were confirmed to be infected with Plasmodium species by microscopy and rapid diagnostic tests (RDTs), respectively. The geometric mean of parasite density was 2392 parasites per microliter (μl); 2275/ μl for P. falciparum and 2032/ μl for P. vivax. Parasitemia was more likely to occur in primigravidae (Adjusted odds ratio (AOR): 9.4, 95% confidence interval (CI): 4.3–60.5), secundigravidae (AOR: 6.3, 95% CI: 2.9–27.3), using insecticide treated bed net (ITN) sometimes (AOR: 3.2, 95% CI: 1.8- 57.9), not using ITN at all (AOR: 4.6, 95% CI: 1.4–14.4) compared to multigravidae and using ITN always, respectively.

Conclusion

Asymptomatic malaria in this study is low compared to other studies’ findings. Nevertheless, given the high risk of malaria during pregnancy, pregnant women essentially be screened for asymptomatic Plasmodium infection and be treated promptly via the antenatal care (ANC) services.

Long-run relative importance of temperature as the main driver to malaria transmission in Limpopo Province, South Africa: a simple econometric approach

Malaria in Limpopo Province of South Africa is shifting and now observed in originally non-malaria districts, and it is unclear whether climate change drives this shift. This study examines the distribution of malaria at district level in the province, determines direction and strength of the linear relationship and causality between malaria with the meteorological variables (rainfall and temperature) and ascertains their short- and long-run variations. Spatio-temporal method, Correlation analysis and econometric methods are applied. Time series monthly meteorological data (1998-2007) were obtained from South Africa Weather Services, while clinical malaria data came from Malaria Control Centre in Tzaneen (Limpopo Province) and South African Department of Health. We find that malaria changes and pressures vary in different districts with a strong positive correlation between temperature with malaria, r = 0.5212, and a weak positive relationship for rainfall, r = 0.2810. Strong unidirectional causality runs from rainfall and temperature to malaria cases (and not vice versa): F (1, 117) = 3.89, ρ = 0.0232 and F (1, 117) = 20.08, P < 0.001 and between rainfall and temperature, a bi-directional causality exists: F (1, 117) = 19.80; F (1,117) = 17.14, P < 0.001, respectively, meaning that rainfall affects temperature and vice versa. Results show evidence of strong existence of a long-run relationship between climate variables and malaria, with temperature maintaining very high level of significance than rainfall. Temperature, therefore, is more important in influencing malaria transmission in Limpopo Province.

Role of asymptomatic carriers and weather variables in persistent transmission of malaria in an endemic district of Assam, India

Background

Malaria transmission is perennial in the Assam–Arunachal Pradesh interstate border areas in the Sonitpur district of Assam, India. A yearlong study was carried out on the incidence of symptomatic and asymptomatic malaria and the role of asymptomatic malaria carriers in persistent transmission of the disease. The relationships between malaria incidence and weather parameters were also investigated.

Methods

Active and mass blood surveys were conducted on a monthly basis in Bengenajuli, Sapairaumari Pathar, and Nigam villages near the Assam–Arunachal Pradesh border. Epidemiological indices were estimated for malaria-positive cases. Multiple linear regression between monthly malaria incidence and monthly average temperature, and relative humidity along with monthly total rainfall was carried out. The known malaria vectors collected in CDC light traps were identified and recorded.

Results

Slide positivity rate (SPR) and Plasmodium falciparum percent (Pf%) for symptomatic malaria were 26.1 and 79.8, respectively. Prevalence of malaria vectors was observed throughout the year with varying density. Anopheles philippinensis/nivipes and A. annularis were predominant among the seven known vector species recorded currently. Asymptomatic parasitemia was detected throughout the year with SPR ranging from 4.8 to 5.3. Monthly rainfall with 1-month lag had the highest correlation (r=0.92) with SPR. The relationship between SPR and weather factors was established as SPR=−114.22+0.58 T_min+1.38 RH+0.03 RF (R²=0.89; p=0.00).

Conclusion

Low and relatively constant levels of asymptomatic parasitemia was present in the study area. High malaria vector density and presence of asymptomatic malaria parasite carriers were responsible for persistent malaria transmission in the region. This study concludes that passive detection and prompt treatment of asymptomatic carriers is essential for preventing persistent disease transmission. Rainfall along with some other weather variables may be used for predicting the malaria epidemics in the region. The predictive information could be useful to target resources more effectively.

Statistical modeling of the abundance of vectors of West African Rift Valley fever in Barkédji, Senegal

Rift Valley fever is an emerging mosquito-borne disease that represents a threat to human and animal health. The exophilic and exophagic behavior of the two main vector in West Africa (Aedes vexans and Culex poicilipes), adverse events post-vaccination, and lack of treatment, render ineffective the disease control. Therefore it is essential to develop an information system that facilitates decision-making and the implementation of adaptation strategies. In East Africa, RVF outbreaks are linked with abnormally high rainfall, and can be predicted up to 5 months in advance by modeling approaches using climatic and environmental parameters. However, the application of these models in West Africa remains unsatisfactory due to a lack of data for animal and human cases and differences in the dynamics of the disease emergence and the vector species involved in transmission. Models have been proposed for West Africa but they were restricted to rainfall impact analysis without a spatial dimension. In this study, we developed a mixed Bayesian statistical model to evaluate the effects of climatic and ecological determinants on the spatiotemporal dynamics of the two main vectors. Adult mosquito abundance data were generated from July to December every fortnight in 2005-2006 at 79 sites, including temporary ponds, bare soils, shrubby savannah, wooded savannah, steppes, and villages in the Barkédji area. The results demonstrate the importance of environmental factors and weather conditions for predicting mosquito abundance. The rainfall and minimum temperature were positively correlated with the abundance of Cx. poicilipes, whereas the maximum temperature had negative effects. The rainfall was negatively correlated with the abundance of Ae. vexans. After combining land cover classes, weather conditions, and vector abundance, our model was used to predict the areas and periods with the highest risks of vector pressure. This information could support decision-making to improve RVF surveillance activities and to implement better intervention strategies.

Common mental disorder symptoms among patients with malaria attending primary care in Ethiopia: a cross-sectional survey

Background

Common Mental Disorders (CMDs) are frequent among patients attending primary care. In Africa, CMDs are often misdiagnosed as physical illnesses because many of the patients complain of somatic symptoms of mental distress. We explored whether there was difference in the levels of CMD symptoms between patients with thick film confirmed and clinical cases of malaria with negative thick film in primary care.

Methods

A cross-sectional comparative study was conducted on 300 adults with a clinical diagnosis of malaria in primary care centres in Jimma, Ethiopia. Patients were recruited consecutively until 100 cases of ‘malaria’ with a negative thick film and 200 cases of malaria with a positive thick film consented to participate. The 20-item Self-Reporting Questionnaire (SRQ-20) was used to measure CMD. The non-parametric Wilcoxon rank-sum test was used to explore the association between thick film result and CMD.

Results

Participants had a mean age of 28.2 (S.D = 10.9) years and the majority (57.3%) were women. The prevalence of high CMD symptoms (six or more symptoms on the SRQ-20) was 24.5%. Suicidal ideation was reported by 13.8% of the participants. CMD symptoms were significantly higher in patients who had taken medication prior to visiting the primary care (p = 0.012) and in those whose symptoms had been present for seven days or more (p = 0.041). There was no statistically significant association between level of CMD symptoms and having a negative thick film result (OR 0.98; 95%CI 0.92, 1.04) or objective presence of fever (OR 1.04; 95%CI 0.93, 1.15).

Conclusions

CMD symptoms among cases of malaria did not appear to be associated with a negative thick film result. The high levels of CMD symptoms, including suicidal ideation, calls for further studies to investigate the persistence and progression of these symptoms following resolution of the acute malarial episode.

Agro-ecology, household economics and malaria in Uganda: empirical correlations between agricultural and health outcomes

BACKGROUND

This paper establishes empirical evidence relating the agriculture and health sectors in Uganda. The analysis explores linkages between agricultural management, malaria and implications for improving community health outcomes in rural Uganda. The goal of this exploratory work is to expand the evidence-base for collaboration between the agricultural and health sectors in Uganda.

METHODS

The paper presents an analysis of data from the 2006 Uganda National Household Survey using a parametric multivariate Two-Limit Tobit model to identify correlations between agro-ecological variables including geographically joined daily seasonal precipitation records and household level malaria risk. The analysis of agricultural and environmental factors as they affect household malaria rates, disaggregated by age-group, is inspired by a complimentary review of existing agricultural malaria literature indicating a gap in evidence with respect to agricultural management as a form of malaria vector management. Crop choices and agricultural management practices may contribute to vector control through the simultaneous effects of reducing malaria transmission, improving housing and nutrition through income gains, and reducing insecticide resistance in both malaria vectors and agricultural pests.

RESULTS

The econometric results show the existence of statistically significant correlations between crops, such as sweet potatoes/yams, beans, millet and sorghum, with household malaria risk. Local environmental factors are also influential- daily maximum temperature is negatively correlated with malaria, while daily minimum temperature is positively correlated with malaria, confirming trends in the broader literature are applicable to the Ugandan context.

CONCLUSIONS

Although not necessarily causative, the findings provide sufficient evidence to warrant purposefully designed work to test for agriculture health causation in vector management. A key constraint to modeling the agricultural basis of malaria transmission is the lack of data integrating both the health and agricultural information necessary to satisfy the differing methodologies used by the two sectors. A national platform for collaboration between the agricultural and health sectors could help align programs to achieve better measurements of agricultural interactions with vector reproduction and evaluate the potential for agricultural policy and programs to support rural malaria control.

Analysis of trend of malaria prevalence in south-west Ethiopia: a retrospective comparative study

Background

The temporal analysis of pertinent malaria data on the health care system is crucially important to measure success or failure of malaria programmes and identify remaining malaria hot spots. The objectives of this study were to analyse and compare trends of malaria prevalence around Gilgel-Gibe Hydroelectric Dam (GGHD), and a control site over an eight-year period.

Methods

A retrospective record review of health care services was conducted in southwest Ethiopia. Records of malaria cases over an eight-year period in primary health care units of two localities were reviewed. One study site was selected from villages around a man-made lake, GGHD, within a distance of 10 km, and a control site with similar geographic features was identified. Data were summarized in tables; prevalence of malaria was analysed and described by person, place and time using line graphs. Odds ratio was used to examine significant difference of malaria occurrence in the two sites.

Results

Records of 163,918 malaria cases registered over eight years (September 2003 to August 2011) were explored. Close to one thirds (32.7%) of these cases were from GGHD site and two-thirds (67.3%) of them were from the control site. Among the confirmed cases, Plasmodium falciparum constituted 54.6%, Plasmodium vivax accounted for 41.6%, and mixed infection was 3.8%. There were three peaks of malaria prevalence in the control site whereas only one major peak was identified during the eight-year period in GGHD site; and prevalence of malaria in GGHD site was lower than control site. Children in the age range ten to 14 years were the most affected by the disease, followed by children below the age group five to nine years, which demands due consideration in the effort of malaria control.

Conclusions

More malaria prevalence was observed in the control site compared to GGHD site almost throughout the time period considered. The present finding did not show evidence of the excess malaria burden in the GGHD site due to the presence of the dam.

A mixed method to evaluate burden of malaria due to flooding and waterlogging in Mengcheng County, China: a case study

Background

Malaria is a highly climate-sensitive vector-borne infectious disease that still represents a significant public health problem in Huaihe River Basin. However, little comprehensive information about the burden of malaria caused by flooding and waterlogging is available from this region. This study aims to quantitatively assess the impact of flooding and waterlogging on the burden of malaria in a county of Anhui Province, China.

Methods

A mixed method evaluation was conducted. A case-crossover study was firstly performed to evaluate the relationship between daily number of cases of malaria and flooding and waterlogging from May to October 2007 in Mengcheng County, China. Stratified Cox models were used to examine the lagged time and hazard ratios (HRs) of the risk of flooding and waterlogging on malaria. Years lived with disability (YLDs) of malaria attributable to flooding and waterlogging were then estimated based on the WHO framework of calculating potential impact fraction in the Global Burden of Disease study.

Results

A total of 3683 malaria were notified during the study period. The strongest effect was shown with a 25-day lag for flooding and a 7-day lag for waterlogging. Multivariable analysis showed that an increased risk of malaria was significantly associated with flooding alone [adjusted hazard ratio (AHR)  = 1.467, 95% CI = 1.257, 1.713], waterlogging alone (AHR = 1.879, 95% CI = 1.696, 2.121), and flooding and waterlogging together (AHR = 2.926, 95% CI = 2.576, 3.325). YLDs per 1000 of malaria attributable to flooding alone, waterlogging alone and flooding and waterlogging together were 0.009 per day, 0.019 per day and 0.022 per day, respectively.

Conclusion

Flooding and waterlogging can lead to higher burden of malaria in the study area. Public health action should be taken to avoid and control a potential risk of malaria epidemics after these two weather disasters.

Comparison of Giemsa microscopy with nested PCR for the diagnosis of malaria in North Gondar, north-west Ethiopia

BACKGROUND

Malaria remains one of the leading communicable diseases in Ethiopia. Early diagnosis combined with prompt treatment is one of the main strategies for malaria prevention and control. Despite its limitation, Giemsa microscopy is still considered to be the gold standard for malaria diagnosis. This study aimed to compare the performance of Giemsa microscopy with nested polymerase chain reaction (nPCR) for the diagnosis of malaria in north-west Ethiopia.

METHODS

A cross sectional study was conducted in public health facilities in North Gondar, from March 2013 to April 2013. A total number of 297 subjects with suspected malaria were enrolled in the study. Finger-prick blood samples were collected and examined for Plasmodium parasites using Giemsa microscopy and standard nPCR.

RESULTS

Among the study participants, 61.6% (183/297) patients tested positive for malaria by Giemsa microscopy of which, 72.1% (132/183) and 27.9% (51/183) were diagnosed as Plasmodium falciparum and Plasmodium vivax, respectively. By nPCR, 73.1% (217/297) were malaria-positive. Among microscopy-negative samples, 13.1% (39/297) samples turned malaria-positive in nPCR. In nPCR, the rate of mixed Plasmodium infections was 4.7% (14/297) and 3.03% (9/297) were positive for Plasmodium ovale. Using nPCR as reference the sensitivity, specificity, positive predictive and negative predictive values of Giemsa microscopy were 82.0%, 93.8%, 97.3% and 65.8%, respectively, with a good agreement (κ = 0.668) to nested PCR. The sensitivity and specificity of Giemsa microscopy in identifyingP. falciparium infections were 74.0% and 87.4% and 63.2% and 96.5% for P. vivax infections, respectively.

CONCLUSION

Although Giemsa microscopy remains the gold standard for malaria diagnosis in resource-limited environments, its sensitivity and specificity as compared to nPCR is limited suggesting exploration of novel rapid and simplified molecular techniques for malaria-endemic countries. A high rate of misclassification and misidentification highlights the importance of adequate training for staff involved in malaria diagnosis.