Etiology of Diarrhea in Children Younger Than 5 Years Attending the Bengo General Hospital in Angola

High Detection Rate of Rotavirus Infection Among Children Admitted with Acute Gastroenteritis to Six Public Hospitals in Luanda Province After the Introduction of Rotarix® Vaccine: A Cross-Sectional Study

Rotavirus group A (RVA) is a major cause of pediatric acute gastroenteritis (AGE). Vaccination is an effective public health strategy and Angola implemented it in 2014. This hospital-based study aimed to estimate the prevalence of RVA infection and the severity of AGE in children under five years of age treated at six hospitals in Luanda Province. Between April 2021 and May 2022, 1251 fecal samples were screened by an immunochromatographic rapid test (SD Bioline). Data on socio-demographic profile, nutritional status, and clinical assessment were obtained. The association of RVA infection and AGE severity with possible risk factors was evaluated with a binary logistic regression model. Overall, the detection rate was 57.8% and girls tend to be more often infected than boys (55.2%). Infection was more common in the youngest group (1 to 6 months, 60.3%). Important sources of RVA infection were drinking water kept in tanks (57.9%) and private sanitary facilities with piped water (61%). Surprisingly, according to the Vesikari Scale score, the most severe symptoms were observed in children vaccinated with two doses (80.7%). RVA prevalence remains high despite vaccination, and further studies should address the association between infection sources and disease severity, as well as the causes underlying vaccine (un)effectiveness.

The Impact of Campylobacter, Salmonella, and Shigella in Diarrheal Infections in Central Africa (1998-2022): A Systematic Review

BACKGROUND

Gastric diseases caused, in particular, by Campylobacter, non-typhoidal Salmonella, and Shigella resulting from food and/or water problems, are a disproportionately distributed burden in developing countries in Central Africa. The aim of this work was to compile a list of studies establishing the prevalence of the involvement of these bacterial genera in diarrheal syndromes in Central Africa from 1998 to 2022.

METHODS

The Preferred Reporting Articles for Systemic Reviews and Meta-Analyses, six (6) database (Pubmed, Google Scholar, Semantic Scholar, Freefullpdf, and Scinapse) were perused for research on the role of Campylobacter, Salmonella and Shigella diarrheal infections in humans and animals, in 9 country of Central Africa over from 1998 to 2022.

RESULTS

Seventeen articles were selected, including 16 on humans and one on animals. These data were recorded in 6 of the 9 countries of Central Africa, including Gabon (5), Angola (3), Cameroon (3), the Democratic Republic of Congo (3), Chad (2), and the Central African Republic (1). Mono-infections with Salmonella spp. were the most predominant (55.56%, n = 5/9), followed by an equal proportion of Campylobacter spp. and Shigella spp. with 44.44% (4/9), respectively and, co-infections with Campylobacter/Salmonella spp. and Salmonella/Shigella spp. with a prevalence of 11.11% (1/9) respectively. The most used diagnostic tool was conventional culture (82.35%) against 17.65% for PCR or real-time PCR.

CONCLUSION

Despite the paucity of recorded data on the prevalence of diarrheal infections due to Campylobacter in this sub-region, it is crucial that scientific studies focus on the diagnosis and monitoring of this zoonotic bacterium. Also, improved diagnosis will necessarily involve the integration of molecular tools in the diagnosis of these diarrheic syndromes in both humans and animals.

Detection and complete genome sequence analysis of human adenovirus in children with acute diarrhea in Yunnan, China, 2015-2021

The aims of this study were to determine the distribution and prevalence of gastroenteritis caused by human adenovirus (HAdV) in children in Yunnan province, China, in 2015-2021 and to identify preventive measures that can be taken to reduce morbidity and mortality in children.HAdV is a significant agent of diarrhea in children, but limited data are available regarding the epidemiology and genetic diversity of HAdV in children with diarrhea in Yunnan province, China. A total of 1754 fecal samples were subjected to real-time RT-PCR to detect and quantify HAdV. Positive samples were further analyzed using next-generation sequencing (NGS), and epidemiological data were analyzed as well.1754 patients with diarrhea were enrolled, of which 1041 were male and 713 were female (M:F ratio: 1.46). Seventy-two stool samples out of 1754 (4.10%) were positive for HAdV. The detection rates of all age groups varied from 2.50-4.78%. The highest incidence of HAdV was observed in children under 2 years of age, especially in children 12-24 months-old. From 2015-2021, the annual detection rate ranged from 1.62-12.26%. HAdV was detected throughout the year, but with marked seasonality. Children were most likely to be positive for HAdV in June and November. We detected HAdV in 15.53% (16/103) of samples collected in June and in 8.19% (14/171) of those collected in November. The entire viral genome was successfully sequenced for 13 of the 72 HAdV-positive samples, and 76.92% (10/13) of these were classified as genotype F41 and 23.08% (3/13) were classified as genotype C2.ConclusionsIn Yunnan province, children of all ages are susceptible to HAdV infection, but there has been marked variation in the yearly prevalence. The highest rate of HAdV detection was in June, followed by November. Priority should be given to disease prevention over the development of targeted antiviral therapies, and effective vaccines for preventing HAdV diarrhea are needed. It is also important to establish a surveillance system to collect relevant clinical and epidemiological data quickly in order to assess the potential risk of HAdV infection in children and to identify epidemic strains for the development of effective vaccines.

Diverse genotypes of human enteric and non-enteric adenoviruses circulating in children hospitalized with acute gastroenteritis in Thailand, from 2018 to 2021

Human adenovirus (HAdV) is a common viral pathogen that causes diarrhea in children worldwide. The aim of this study was to investigate the prevalence and genotype diversity of HAdV strains circulating in children admitted to the hospitals with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021. A total of 1,790 stool samples were screened for HAdV by PCR method, and 80 (4.5%) were positive for HAdV. Of these, children under 5 years of age accounted for 90.0% of HAdV-positive cases with the highest infection rate at the age group of 48-60 months old. The infection rate was not significantly different between boys and girls. The HAdV infection was detected sporadically throughout the year without a discrete seasonal pattern. Five species of both enteric and non-enteric HAdVs (A, B, C, E, and F) with 10 different genotypes, including HAdV-F41 (25.0%), HAdV-B3 (17.5%), HAdV-F40 (16.3%), HAdV-C1 (15.0%), HAdV-C5 (7.5%), HAdV-C2 (6.3%), HAdV-B7 (5.0%), HAdV-A12 (3.8%), HAdV-E4 (2.5%), and HAdV-B11 (1.3%), were detected in this study. In conclusion, our study reported the prevalence and seasonality of HAdV infection with a wide variety of HAdV genotypes circulating in children hospitalized with AGE during a period of 2018-2021 in Chiang Mai, Thailand. IMPORTANCE In the present study, the prevalence of human adenovirus (HAdV) infection in children with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021 was detected at 4.5%. Diverse species and genotypes of HAdVs (HAdV-A12, HAdV-B3, HAdV-B7, HAdV-B11, HAdV-C1, HAdV-C2, HAdV-C5, HAdV-E4, HAdV-F40, and HAdV-F41) had been identified. The highest infection rate was found in children aged 48-60 months old. The HAdV infection was detected sporadically throughout the year. These findings imply that a wide variety of HAdV genotypes circulate in pediatric patients with AGE in Chiang Mai, Thailand.

High Burden of Co-Infection with Multiple Enteric Pathogens in Children Suffering with Diarrhoea from Rural and Peri-Urban Communities in South Africa

Infectious diarrhoea contributes to high morbidity and mortality in young children from sub-Saharan Africa. The aim of this study was to assess the prevalence of single and multiple diarrhoeal-causing pathogen combinations in children suffering from diarrhoea from rural and peri-urban communities in South Africa. A total of 275 diarrhoea stool specimens were collected between 2014 and 2016 from Hospitals and Primary Health Care clinics. The BioFire^® FilmArray^® Gastrointestinal panel was used to simultaneously detect 22 diarrhoea pathogens (viruses, bacteria, parasites) known to cause diarrhoea. A total of 82% (226/275) enteric pathogens were detected in the stool specimens. The two most detected bacterial, viral and parasitic pathogens each included: EAEC (42%), EPEC (32%), Adenovirus F40/41 (19%), Norovirus (15%), Giardia (8%) and Cryptosporidium (6%), respectively. Single enteric pathogen infections were recorded in 24% (65/275) specimens with EAEC, and Norovirus was found in 26% (17/65) and 14% (9/65) of the specimens, respectively. Multiple enteric pathogen combinations were recorded in 59% (161/275) of the stool specimens with 53% (85/161) containing two pathogens, 22% (35/161) containing three pathogens and 25% (41/161) containing four or more pathogens. The results from this study demonstrated the complex nature of pathogen co-infections in diarrhoeal episodes which could have an impact on treatment effectiveness.

Isolation and Genotyping of Adenoviruses from Wastewater and Diarrheal Samples in Egypt from 2016 to 2020

Human adenoviruses (HAdV) are a prevalent cause of diarrhea in children all over the world. Adenoviral infections are responsible for 2% to 10% of diarrheic cases. A long-term investigation was required to gain better knowledge about the incidence of HAdV in Egypt. Herein, we conducted 5 years of detection, isolation, and genotyping of HAdV in fecal and sewage samples from 2016 to 2020, in Cairo, Egypt using molecular and cell culture assays. Human adenoviruses were identified in 35 of 447 fecal samples (7.8%), but only 53.3% (64/120) of the sewage samples. Children under the age of two had the highest positive rate for HAdV infection (77.1%). Species F of HAdV was the most common prevalent genotype in fecal and sewage samples, at 88.5% and 85.9%, respectively. The most prevalent genotypes detected in fecal samples were HAdV-41 (71.2%), HAdV-40 (17.2%), HAdV-6 (5.7%), and HAdV-1 (5.7%). In contrast, the most common genotypes in sewage samples were HAdV-41 (64%), HAdVs-40 (21.8%), HAdV-6 (7.8%), HAdV-1 (4.7%), and HAdV-2 (1.6%). HAdV was detected in all months of the year, with a peak period for clinical samples from December to February (p < 0.001), which matched Egypt’s rainy season, while the monthly distribution of HAdV in sewage samples remained consistent throughout the year, with no statistically significant peak period. Interestingly, the HAdV-type 41 genotype was the most common genotype during all of the years of this study. Throughout a 5-year period, our work revealed the infection rate, seasonal distribution, virus isolates, and genetic diversity of HAdV infections in environmental and clinical samples in Cairo, Egypt. Non-enteric adenovirus types (1, 2 and 6), as well as enteric adenovirus (41 and 40), may play a key role in gastroenteritis in Egypt.

Updates on the worldwide burden of amoebiasis: A case series and literature review

BACKGROUND

Amoebiasis is an intestinal and tissue parasitic infection caused by the protozoan Entamoeba histolytica. Despite significant medical importance and worldwide dispersion, little is known about the epidemiology and distinct geographical distribution of various clinical forms of amoebiasis in the world. In this study, we present an amoebiasis case series referred to Avicenne Hospital (Bobigny, France) from 2010 to 2022 followed by an overview of the released literature to explore diverse clinico-pathology of amoebiasis and to update the actual epidemiological situation of this parasitosis worldwide.

METHODS

The referred patients underwent a combination of clinical and parasitological examinations and imaging. The study was followed by an overview of released literature performed based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline.

RESULTS

A total of 15 patients with amoebiasis were diagnosed with an average age of 48.5 years old at the occurrence time of infection. Men (78%) were the most affected patients. Most of the cases were reported following a trip to endemic regions, such as Mali, India, Nepal, Algeria, Cameroon or Congo. All of the processed patients exhibited a hepatic amoebiasis. Amoebic abscess was observed in all cases with an average size of 6.3 cm. Of these patients, seven cases (46.7%) benefited from drainage following a risk of rupture or superinfection of the abscess. A compilation of findings extracted from 390 scientific publications via seven major medical databases, allowed us to update the main epidemiological and clinical events that has led to the current worldwide expansion of amoebiasis. We presented a clinical and epidemiological overview of the amoebiasis accompanied with a worldwide illustrative map displaying the current distribution of known amoebiasis foci in each geographical ecozone of Asia, Europe, Africa, Americas, and Australia.

CONCLUSIONS

Although Metropolitan France is not known as an endemic region of amoebiasis, amoebic liver abscess was the most frequent clinical form observed among our 15 patients processed. Most of infected patients had a history of travel to or lived-in endemic areas before arriving in France.

Wasting, Stunting, and Anemia in Angolan Children after Deworming with Albendazole or a Test-and-Treat Approach for Intestinal Parasites: Binary Longitudinal Models with Temporal Structure in a Four-Arm Randomized Trial

Undernutrition, anemia, and intestinal parasitic infections are public health problems in Angola, especially in pre-school children. We analyzed binary data from a longitudinal four-arm randomized parallel trial conducted in Bengo Province, northern Angola, over the course of two years, with seven follow-up assessments to explore the effects of four interventions (deworming and a test-and-treat approach for intestinal parasites, at both the individual and household levels) on wasting and stunting, and to understand their indirect benefits for anemia, malaria, diarrhea, and vomiting. A total of 121 children with intestinal parasitic infections received baseline treatment, and were allocated to the four arms (1:1:1:1). Using continuous outcome variables of height-for-age (HAZ) and weight-for-height (WHZ) statistical approaches did not reveal a clear benefit of any particular arm (Pathogens 2021, 10, 309). Next, HAZ and WHZ were transformed into binary variables of stunting and wasting, respectively, considering their mild-to-severe (Z-score < −1) and moderate-to-severe degrees (Z-score < −2). Original clinical data (on anemia, diarrhea, vomiting, and malaria) were also analyzed. From a binary longitudinal analysis with different dependence structures, using the R package bild, fitted models revealed the potential benefit of a test-and-treat approach at the individual level for wasting compared with annual albendazole at the individual level, especially considering mild-to-severe forms (ORadj = 0.27; p = 0.007). All arms showed similar effects on stunting, compared with annual albendazole, at a 5% significance level. Time and age at baseline presented favorable effects in the percentage of stunting using both severity degrees. Results showed a decreased chance of having anemia and diarrhea over time, although with no significant differences between arms. Data from longitudinal studies are essential to study the direct and indirect effects of interventions, such as deworming, and to explore additional approaches aiming at better understanding the temporal structure of nutrition and health outcomes in children.

Molecular and epidemiological characterization of human adenoviruses infection among children with acute diarrhea in Shandong Province, China

Background

Human adenovirus (HAdV) had been recognized as one of the most common enteric viruses associated with acute diarrhea in children. The present study was carried out to demonstrate the molecular and epidemiological characterization of HAdV Infections among children in Shandong province in China between July 2017 and June 2018.

Methods

Fecal specimens were collected from children under 5 years old with acute diarrhea. DNA was extracted from the stool specimens and adenovirus DNA was detected by PCR amplification with specific primers. The amplification products were subjected to electrophoresis and visualized on a UV transilluminator. All positive RT-PCR amplification products were sequenced and the obtained sequences analyzed by MEGA (version 7.0). Demographic information and clinical manifestation data were also analyzed.

Results

In total, 656 fecal specimens were collected and the overall positive rate of HAdV was 7.47%. HAdV infections were detected in all age groups, in which children aged 13–24 months presented the highest positive rate. Seasonal pattern could be observed with a peak in December, January and February. Diarrhea, vomiting, dehydration and fever were the main clinical manifestations, in which vomiting was the most common accompanied symptom. By phylogenetic analysis, four species (A, B, C, and F) were detected and seven different serotypes were identified. HAdV-41 (48.98%, 24/49) was the most common serotype followed by HAdV-3 (18.37%, 9/49), HAdV-31 (14.29%, 7/49), HAdV-7 (8.16%, 4/49), HAdV-40 (4.08%, 2/49), HAdV-1 (4.08%, 2/49) and HAdV-2 (2.04%, 1/49).

Conclusion

This study indicated that HAdV infection was an important cause of acute diarrhea among children under 5 years old in Shandong province. The results will contribute to (a) increase understanding of the role of HAdV in diarrheal children and enhance identification of the predominant diarrhea pathogen for diagnosis; (b) avoid abuse of antibiotics; (c) monitor the change of prevalent HAdV serotypes and promote vaccine development and vaccination.

A meta-analysis of Cryptosporidium species in humans from southern Africa (2000-2020)

Abstract

The epidemiology of cryptosporidiosis in southern Africa is largely unknown. The disease is associated with diarrhea and nutritional deficiencies, leading to severe morbidity and mortality among immune-compromised patients. This study aimed to assess the pooled prevalence of Cryptosporidium spp. infection among immune-compromised humans in southern Africa over the past 20 years. Reports of Cryptosporidium spp. infection in humans published between 2000 and 2020 using Google Scholar, PubMed, Ovid Medline, African Journal Online (AJOL), and Web of Science literature databases were obtained. Inclusion criteria of sorted articles for Cryptosporidium spp. infection were standardized using preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. A total of 22 eligible studies were sorted for meta-analysis. Overall prevalence of Cryptosporidium spp. infection in southern African countries with reports was 16.8% (95% CI 9.7-25.3). Sub-group analysis showed a pooled prevalence of 25.2, 20.5, and 17.9% among HIV/AIDS patients, children, and diarrhoeic individuals, respectively. Pooled prevalence was highest in South Africa and lowest in Zimbabwe across examined individuals. The pooled prevalence of Cryptosporidium spp. infections in diarrhoeic patients was highest in individuals from Botswana (17.6%) which is significantly different (Χ ² = 9.337; P = 0.002) from South Africans (12.7%). South African individuals with HIV/AIDS showed the highest pooled prevalence of Cryptosporidium infections than other countries. The high prevalence of Cryptosporidium spp. infections among immune-compromised patients in southern Africa showed that the pathogen is of significant importance in this region. Continuous studies on the genetic characterization of Cryptosporidium spp. isolates and associated risk factors are needed across southern Africa to identify the predominant subtypes in humans.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-021-01436-4.

Prevalence of Pathogens in Young Children Presenting to Hospital with Diarrhea from Lambaréné, Gabon

Diarrheal disease is the second most frequent cause of mortality in children younger than 5 years worldwide, causing more than half a million deaths each year. Our knowledge of the epidemiology of potentially pathogenic agents found in children suffering from diarrhea in sub-Saharan African countries is still patchy, and thereby hinders implementation of effective preventative interventions. The lack of cheap, easy-to-use diagnostic tools leads to mostly symptomatic and empirical case management. An observational study with a total of 241 participants was conducted from February 2017 to August 2018 among children younger than 5 years with diarrhea in Lambaréné, Gabon. Clinical and demographic data were recorded, and a stool sample was collected. The samples were examined using a commercial rapid immunoassay to detect Rotavirus/adenovirus, conventional bacterial culture for Salmonella spp., and multiplex real-time PCR for Cryptosporidium spp., Giardia lamblia, Cyclospora cayetanensis, enterotoxigenic Escherichia coli (ETEC), and enteroinvasive Escherichia coli (EIEC)/Shigella. At least one infectious agent was present in 121 of 241 (50%) samples. The most frequently isolated pathogens were EIEC/Shigella and ETEC (54/179; 30.2% and 44/179; 24.6%, respectively), followed by G. lamblia (33/241; 13.7%), Cryptosporidium spp. (31/241; 12.9%), and Rotavirus (23/241; 9.5%). Coinfection with multiple pathogens was observed in 33% (40/121) of the positive cases with EIEC/Shigella, ETEC, and Cryptosporidium spp. most frequently identified. Our results provide new insight into the possible causes of diarrheal disease in the Moyen-Ogooué region of Gabon and motivate further research on possible modes of infection and targeted preventive measures.

Effectiveness of Nutrition and WASH/malaria educational community-based interventions in reducing anemia in children from Angola

We found no published data in Angola regarding the effect of combining nutrition-specific and nutrition-sensitive approaches in the reduction of anemia in preschool children. Thus, we implemented a cluster-randomized controlled trial to determine the effectiveness of two educational-plus-therapeutic interventions, in Nutrition and WASH/Malaria, in reducing anemia. We compared them to (1) a test-and-treat intervention and (2) with each other. A block randomization was performed to allocate 6 isolated hamlets to 3 study arms. A difference-in-difference technique, using Fit Generalized estimating models, was used to determine differences between the children successfully followed in all groups, between 2015 and 2016. We found no significant differences in anemia´s and hemoglobin variability between educational and the control group. However, the WASH/Malaria group had 22.8% higher prevalence of anemia when compared with the Nutrition group, having also higher prevalence of P. falciparum. Thus, our results suggest that adding a 12-month educational Nutrition or a WASH/Malaria component to a test-and-treat approach may have a limited effect in controlling anemia. Possibly, the intensity and duration of the educational interventions were not sufficient to observe the amount of behavior change needed to stop transmission and improve the general child feeding practices.

Impact of Annual Albendazole versus Four-Monthly Test-and-Treat Approach of Intestinal Parasites on Children Growth-A Longitudinal Four-Arm Randomized Parallel Trial during Two Years of a Community Follow-Up in Bengo, Angola

Malnutrition and intestinal parasites continue to have serious impacts on growth and cognitive development of children in Angola. A longitudinal four-arm randomized parallel trial was conducted to investigate if deworming with a single annual dose of albendazole (annual-ALB) or a four-monthly test-and-treat (4TT) intestinal parasites approach at individual or household levels improve nutritional outcomes of pre-school children in Bengo province. Children with intestinal parasites (n = 121) were randomly assigned (1:1:1:1) to arm A1: annual-ALB*individual level; A2: annual-ALB*household level; A3: 4TT*individual; and A4: 4TT*household level. At baseline, 4, 8, 12, 16, 20, and 24 months of follow-up, growth was assessed by height, weight, height-for-age, weight-for-height, weight-for-age, and mid-upper arm circumference. Intention-to-treat analysis was done using non-parametric approach, mixed effect models, and generalized estimating equations (GEE). Initially, 57% and 26% of the children were infected by Giardia lamblia and Ascaris lumbricoides, respectively. This study did not show that a 4TT intestinal parasites approach results on better growth outcomes of children (height, weight, HAZ, WAZ, WHZ and MUACZ) when compared with annual ALB, with exception of height and WHZ using GEE model at 5% level. Positive temporal effects on most nutrition outcomes were observed. Implementing a longitudinal study in a poor setting is challenging and larger sample sizes and 'pure and clean' data are difficult to obtain. Nevertheless, learned lessons from this intensive study may contribute to future scientific research and to tailor multidisciplinary approaches to minimize malnutrition and infections in resource-poor countries.

Iron deficiency anaemia among 6-to-36-month children from northern Angola

BACKGROUND

Angola is one of the southern African countries with the highest prevalence of anaemia. Identifying anaemia determinants is an important step for the design of evidence-based control strategies. In this study, we aim at documenting the factors associated with Iron Deficiency Anaemia (IDA) in 948 children recruited at the Health Research Center of Angola study area during 2015.

METHODS

Data on demographic, socio-economic and parental practices regarding water, sanitation, hygiene, malaria infection and infant and young child feeding were collected, as well as parasitological, biochemical and molecular data. Total and age-stratified multivariate multinomial regression models were fitted to estimate the magnitude of associations between anaemia and its determinants.

RESULTS

Anaemia was found in 44.4% of children, of which 46.0% had IDA. Overall, regression models associated IDA with age, gender and inflammation and non-IDA with age, zinc deficiency and overload, P. falciparum infection, sickle cell trait/anaemia. Among 6-to-23-month-old children IDA was associated with continued breastfeeding and among 24-to-36-month-old children IDA was associated with stunting. Furthermore, zinc deficiency was associated with non-IDA among both age groups children. Inflammation was associated with IDA and non-IDA in either 6-to-23 and 24-to-36 months old children.

CONCLUSION

The main variables associated with IDA and non-IDA within this geographic setting were commonly reported in Africa, but not specifically associated with anaemia. Additionally, the associations of anaemia with inflammation, zinc deficiency and infections could be suggesting the occurrence of nutritional immunity and should be further investigated. In age groups, zinc overload was observed to protect under 6 months children from Non-IDA, while continued breastfeeding was associated with increased IDA prevalence in 6-to-23 months children, and stunting was suggested to increase the odds of IDA in 24-to-36 month children. This site-specific aetiology profile provides an essential first set of evidences able to inform the planification of preventive and corrective actions/programs. Nevertheless, regional and country representative data is needed.

Molecular characterization of Giardia lamblia in children less than 5 years of age with diarrhoea attending the Bengo General Hospital, Angola

Background

Giardia lamblia is a pathogenic intestinal protozoan with high prevalence in developing countries, especially among children. Molecular characterization has revealed the existence of eight assemblages, with A and B being more commonly described in human infections. Despite its importance, to our knowledge this is the first published molecular analysis of G. lamblia assemblages in Angola.

Methods

The present study aimed to identify the assemblages of G. lamblia in children with acute diarrhoea presenting at the Bengo General Hospital, Angola. A stool sample was collected and microscopy and immunochromatographic tests were used. DNA was extracted and assemblage determination was performed through amplification of the gene fragment ssu-rRNA (175 bp) and β-giardin (511 bp) through polymerase chain reaction and DNA sequencing.

Results

Of the 16 stool samples screened, 12 were successfully sequenced. Eleven isolates were assigned to assemblage B and one to assemblage A. Subassemblage determination was not possible for assemblage B, while the single isolate assigned to assemblage A was identified as belonging to subassemblage A3.

Conclusion

This study provides information about G. lamblia assemblages in Bengo Province, Angola and may contribute as a first step in understanding the molecular epidemiology of this protozoan in the country.

GenBank accession numbers for the ssur-RNA gene: MF479750, MF479751, MF479752, MF479753, MF479754, MF479755, MF479756, MF479757, MF479758, MF479759, MF479760, MF479761.

GenBank accession numbers for the β-giardin gene: MF565378, MF565379, MF565380, MF565381.

Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in southern and eastern Africa

Background

The beef tapeworm, Taenia saginata, causing cysticercosis in bovines and taeniosis in humans, is thought to have a global distribution. In eastern and southern Africa, cattle production plays a crucial role in the economy, but a clear overview of the prevalence of T. saginata in the region is still lacking. This review aims to summarize existing knowledge on T. saginata taeniosis and bovine cysticercosis distribution in eastern and southern Africa.

Methods

A systematic review was conducted, that gathered published and grey literature, including OIE reports, concerning T. saginata taeniosis and bovine cysticercosis in eastern and southern Africa published between January 1st, 1990 and December 31st, 2017.

Results

A total of 1232 records were initially retrieved, with 78 full text articles retained for inclusion in the database. Unspecified taeniosis cases were reported for Angola, Ethiopia, Kenya, Madagascar, Malawi, South Africa, Tanzania, Uganda and Zambia, whereas T. saginata taeniosis cases were found for Ethiopia, Kenya, South Africa, Tanzania, Zambia and Zimbabwe. The prevalence of taeniosis ranged between 0.2–8.1% based on microscopy, and between 0.12–19.7% based on coproAg-ELISA. In Ethiopia, the percentage of tapeworm self-reporting was high (45.0–64.2%), and a substantial number of anthelmintic treatments were reported to be sold in towns. The presence of bovine cysticercosis was reported in all 27 countries/territories included in the study, except for Rwanda and Somalia, Comoros, Madagascar, Mauritius, Mayotte, Seychelles and Socotra. The prevalence of cysticercosis ranged between 0.02–26.3% based on meat inspection, and between 6.1–34.9% based on Ag-ELISA.

Conclusions

Although T. saginata has been reported in the majority of countries/territories of the study area, T. saginata taeniosis/cysticercosis remains a largely ignored condition, probably due to the absence of symptoms in cattle, the lack of data on its economic impact, and the fact that human taeniosis is considered a minor health problem. However, the occurrence of bovine cysticercosis is a clear sign of inadequate sanitation, insufficient meat inspection, and culinary habits that may favour transmission. Measures to reduce transmission of T. saginata are therefore warranted and the infection should be properly monitored.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3163-3) contains supplementary material, which is available to authorized users.

Potential Diarrheal Pathogens Common Also in Healthy Children in Angola

BACKGROUND

Globally, diarrhea kills almost 1500 children daily. In diagnostics, molecular methods are replacing traditional assays. We aimed to investigate enteropathogens in children with and without diarrhea in Luanda, the capital of Angola.

METHODS

One hundred and ninety-four stool samples from 98 children with acute diarrhea and 96 children without diarrhea were investigated for 17 enteropathogens with multiplex real-time polymerase chain reaction.

RESULTS

The median age of children was 10.5 months. Enteropathogens, bacteria, viruses and parasites were detected in 91%, 78%, 50% and 25%, respectively. A positive finding was significantly (P = 0.003) more common in diarrhea when testing for all pathogens combined, for bacteria alone and for viruses alone. More than one pathogen was found more frequently in diarrhea than in non-diarrhea stool samples, in 87% and in 59% (P < 0.0001), respectively. The median number (interquartile range) of pathogens detected was 3 (2) versus 1.5 (2; P < 0.0001), respectively. When age was taken into account, diarrhea was found to be associated with enterotoxigenic and enteroaggregative Escherichia coli, Shigella, Campylobacter, rotavirus, sapovirus and Cryptosporidium.

CONCLUSIONS

Multiplex polymerase chain reaction detected enteropathogens in almost all stool samples of children in Luanda, albeit this occurred more often in diarrhea. Children with diarrhea showed more mixed infections than children without diarrhea.

Genetic diversity of norovirus in children under 5 years of age with acute gastroenteritis from Angola

Norovirus (NoV) is a major cause of acute gastroenteritis (AGE). In this study, we investigated the genetic diversity of NoV strains identified in children under 5 years of age with AGE in four provinces of Angola. Faecal samples from 343 children were screened for NoV by an in house real-time PCR assay and genotyping was performed by partial capsid gene sequencing. NoV was detected in 17.4% (58/334) of the samples, with high detection rates in children <6 months old (19%) and in children aged 12-24 months (23%). Genotype diversity was large, as demonstrated by the 11 identified genotypes. GII.4 was the predominant genotype (20% of all NoV-positive samples), followed by GII.6 (15%), GI.3 (12%), GII.7 (10%) and by other genotypes to a lesser extent. Two GII.4 variants, New Orleans 2009 and Sydney 2012, were detected and several genetic clusters were observed for genotypes GI.3, GII.6 and GII.7. The present study shows high detection rates and genetic diversity of circulating NoV genotypes in paediatric AGE samples from Angola. This information emphasises the importance of continuous assessment of NoV burden and evolution in the target population.

Prevalence and molecular characterization of Strongyloides stercoralis, Giardia duodenalis, Cryptosporidium spp., and Blastocystis spp. isolates in school children in Cubal, Western Angola

BACKGROUND

Human infections by the gastrointestinal helminth Strongyloides stercoralis and the enteric protozoans Giardia duodenalis, Cryptosporidium spp. and Blastocystis spp. are not formally included in the list of 20 neglected tropical diseases prioritised by the World Health Organization. Although largely underdiagnosed and considered of lower public health relevance, these infections have been increasingly demonstrated to cause significant morbidity and even mortality globally, particularly among children living in resource-poor settings.

METHODS

In this cross-sectional survey the prevalence, frequency and molecular diversity of S. stercoralis, G. duodenalis, Cryptosporidium spp. and Blastocystis spp. were investigated in a school children population in the province of Benguela (Angola). A total of 351 stool samples were collected during January to June 2015. The presence of S. stercoralis and G. duodenalis was confirmed by qPCR methods. Giardia duodenalis assemblages and sub-assemblages were determined by multilocus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Detection and identification of Cryptosporidium and Blastocystis species and subtypes was carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene of both protozoan. Analyses of risk factors potentially associated with the transmission of these pathogens were also conducted.

RESULTS

Prevalences of S. stercoralis, G. duodenalis, Cryptosporidium spp., and Blastocystis spp. were estimated at 21.4% (95% CI: 17.1-25.7%), 37.9% (95% CI: 32.8-43.0%), 2.9% (95% CI: 1.1-4.5%) and 25.6% (95% CI: 21.18-30.2%), respectively. Overall, 64.1% (225/351) of the children were infected by at least one of the pathogens investigated. Sequence analyses of the 28 G. duodenalis isolates that were successfully genotyped allowed the identification of sub-assemblages AI (14.3%), AII (14.3%), BIII (7.1%) and BIV (25.0%). Discordant typing results AII/AIII and BIII/BIV were identified in 7.1% and 14.3% of the isolates, respectively. A total of five additional isolates (17.9%) were identified as assemblage B. Three Cryptosporidium species including C. hominis (70%), C. parvum (20%) and C. canis (10%) were found circulating in the children population under study. A total of 75 Blastocystis isolates were assigned to the subtypes ST1 (30.7%), ST2 (30.7%), ST3 (36.0%), ST5 (1.3%) and ST7 (1.3%), respectively. Children younger than seven years of age had significantly higher risk of infections by protozoan enteropathogens (PRR: 1.35, P < 0.01), whereas being underweight seemed to have a protective effect against these infections (PRR: 0.74, P = 0.005).

CONCLUSIONS

The burden of disease attributable to human strongyloidiasis, giardiosis, cryptosporidiosis and blastocystosis in Angola is considerably higher than initially estimated in previous surveys. Surveillance and control of these infections should be jointly tackled with formally considered neglected tropical diseases in order to maximize effort and available resources. Our data also demonstrate the added value of using molecular diagnostic methods in high transmission areas.

Intestinal cestodes

PURPOSE OF REVIEW

Cestodes infections in humans are among the most prevalent parasitosis worldwide. Although tapeworm infection is often asymptomatic, they can be associated with a range of symptoms. The landscape of cestode infections is changing with rapid diagnosis techniques and advanced molecular diagnosis aiding in identification of species specific epidemiology.

RECENT FINDINGS

Traditional descriptions of species by location have been challenged with molecular diagnostic techniques, which show variation in distribution of species, thought to be because of globalization and importation of disease.

MAIN THEMES IN LITERATURE

Epidemiology, molecular diagnostic techniques.

SUMMARY

Infection by tapeworms is often asymptomatic or accompanied by mild symptoms though can occasionally cause severe disease and contribute to anemia and malnutrition. Tapeworm infection is most prevalent in resource-poor countries but the distribution is worldwide. Epidemiology of infection is changing because of molecular diagnostics, which allow more accurate tracking of species.

Etiology and pathogenicity of bacterial isolates: a cross sectional study among diarrheal children below five years in central regions of Kenya

INTRODUCTION

Bacterial agents are among pathogens implicated to cause diarrhea in children resulting to huge mortality and morbidities. Bacterial etiologies causing diarrhea in children below five years are rarely investigated in Central Kenya, which would otherwise guide prescription and target health education.

METHODS

A cross-sectional study approach was applied on 163 randomly selected stool samples from children below five years who presented with diarrhea in Murang`a and Muriranja`s hospitals. The objective was to determine the bacterial agents of diarrhea. Enteric bacterial pathogens were cultured using appropriate media and identified. Statistical analyses were performed using STATA v.13. Chi-square or Fisher exact-test were used to check for evidence of relationship whenever applicable.

RESULTS

There were nearly equal distributions in gender 86 (52.8%) female vs. 77 (47.2%) male, majority (35.6%) aged between 0-12 months. Bacterial isolates were highly diverse in female than the male, children aged 49-60 months and least among those aged 0-12 months. A total of 188 bacterial isolates belonging to 11 genera were recovered. The predominant bacteria was nonpathogenic Escherichia coli 85 (45.2%), while 13 (6.9%) Escherichia coli were positive for virulence genes, including 8 (4.3%) positive for LT and STp Shiga-like or Enterotoxigenic Escherichia coli, 3 (1.6%) positive for eae and bfpA Enteropathogenic Escherichia coli and 2 (1.1%) positive for Enteroaggregative Escherichia coli gene. Others included: Salmonella 21 (11.2%), Pseudomonas 14 (7.4%), Shigella 14 (7.4%), Klebsiella 12 (6.4%), Aeromonas 8 (4.3%), Enterobacter 7 (3.7%), Proteus 8 (4.3%), Citrobactor 3 (1.6%), Yersinia 2 (1.1%) and Vibrio 1 (0.5%).

CONCLUSION

Salmonella was the major bacterial isolate and majority of the bacteria were statistically significant cause of diarrhea (p=0.001).

Detection and Molecular Characterization of Human Adenovirus Infections among Hospitalized Children with Acute Diarrhea in Shanghai, China, 2006-2011

Background: Human adenovirus (HAdV) is considered a significant enteropathogen associated with sporadic diarrhea in children. However, limited data are available regarding the epidemiology of HAdV in hospitalized children with viral diarrhea in Shanghai. The aim of this study was to characterize the epidemiology of HAdVs and describe their association with acute diarrhea in hospitalized children. Methods: A total of 674 fecal samples were subjected to PCR or RT-PCR to detect RVA, HuCV, HAstV, and HAdV. Results: HAdV infections were detected in 4.7% (32/674) of specimens, with detection rates of 13.4% (11/82), 4.6% (8/174), 3.2% (4/124), 4.1% (3/74), 2.0% (2/100), and 3.3% (4/120) from 2006 to 2011, respectively. Comprehensive detection of the four viruses revealed the presence of a high percentage (90.6%) of coinfections among HAdV-positive samples, where HAdV+RVA was the most prevalent coinfection. Of the 32 HAdV-positive samples, 50.0% (16/32) were classified as HAdV-41, and 18.8% (6/32) were classified as HAdV-3. Almost 94.0% of children infected with HAdV were less than 24 months of age. Conclusions: These results clearly indicated diversity across the HAdV genotypes detected in inpatient children with acute diarrhea in Shanghai and suggested that HAdVs play a role in children with acute diarrhea.

Prevalence of Strongyloides stercoralis and Other Intestinal Parasite Infections in School Children in a Rural Area of Angola: A Cross-Sectional Study

Strongyloides stercoralis is widely distributed in the tropics and subtropics. The aim of this study was to determine the prevalence of S. stercoralis and other intestinal parasites and identify the risk factors for infection with S. stercoralis in a rural area of Angola. A cross-sectional study was conducted in school-age children (SAC) in Cubal, Angola. A questionnaire collecting clinical and epidemiological variables was used, and two stool samples were collected. A concentration technique (Ritchie) and a technique for detection of larvae migration (Baermann) were performed. Of 230 SAC, 56.1% were female and the mean age was 9.3 years (SD 2.45). Severe malnutrition, according to body mass index (BMI)-for-age, was observed in 20.4% of the SAC, and anemia was found in 59.6%. Strongyloides stercoralis was observed in 28 of the 230 (12.8%) SAC. Eggs of other helminths were observed in 51 (22.2%) students: Hymenolepis spp. in 27 students (11.7%), hookworm in 14 (6.1%), Schistosoma haematobium in four (1.7%), Enterobius vermicularis in four (1.7%), Ascaris lumbricoides in three (1.3%), Taenia spp. in two (0.9%), and Fasciola hepatica in one (0.4%). Protozoa were observed in 17 (7.4%) students. Detection of S. stercoralis was higher using the Baermann technique versus using formol-ether (11.3 vs. 3%). Overall prevalence of S. stercoralis in the school population of 16 studied schools in the municipal area of Cubal was greater than 10%. This fact must be considered when designing deworming mass campaigns. The use of specific tests in larvae detection is needed to avoid overlooking this parasite.

Microbial pathogens associated with acute childhood diarrhoea in Kumasi, Ghana

Background

Diarrhoeal diseases are among the most frequent causes of morbidity and mortality in children worldwide, especially in sub-Saharan Africa. This case–control study was conducted to investigate the bacterial, viral and parasitic pathogens associated with acute diarrhoea among children attending three health facilities in Kumasi, Ghana.

Methods

Stool specimens were collected from 240 children under 5 years of age visiting hospitals in Kumasi, Ghana due to acute diarrhoea and from 107 healthy controls of similar age. Both intestinal and malaria parasites were diagnosed by microscopy whereas rota- and adenoviruses were identified by stool antigen immunochromatograhic testing. Bacterial enteropathogens were detected by conventional culture techniques.

Results

Of all subjects, 23 (6.6%) were positive for malaria parasitaemia, 139 (40.1%) had at least one bacterial agent in their stool and 25 (7.2%) had ova or parasites. Subjects infected with malaria had the highest odds of having diarrhoea [12.0 (95% CI 1.56, 92.35)] followed by those with rotaviruses [4.4 (95% CI 2.05, 9.47)] and bacterial infection [4.99 (95% CI 1.45, 17.17)].

Conclusion

In conclusion, this study was unique as it looked at the three groups of pathogens (parasites, viruses and bacteria) that cause acute diarrhoea in children in the Kumasi metropolis of Ghana. This study has shown for the first time since 2004 that malaria parasitaemia, rotavirus and bacterial infections still remain common pathogens associated with acute childhood diarrhoea in the Kumasi metropolis of Ghana.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Characterization of rotavirus infection in children with acute gastroenteritis in Bengo province, Northwestern Angola, prior to vaccine introduction

BACKGROUND

Rotavirus group A (RVA) is considered the leading cause of pediatric diarrhea, responsible for the high burden of diarrheal diseases in sub-Saharan Africa. Despite recent studies, the existent data are scarce for some African countries like Angola, a country with one of the highest RVA-related death estimates. The aim of this study was to determine the RVA detection rate and circulating genotypes in children less than five years of age with acute gastroenteritis attended at the Bengo General Hospital in Caxito, Bengo province, Angola, before vaccine introduction.

METHODS

Between September 2012 and December 2013, 342 fecal specimens were collected from children enrolled. Positive samples for RVA by immunochromatographic rapid test were G and P-typed by hemi-nested type-specific multiplex PCR, and subgrouped for the VP6 gene. VP4 and VP7 genes from a subset of samples were sequenced for phylogenetic analysis.

RESULTS

During the study period, a high RVA detection rate was registered (25.1%, 86/342). The age group most affected by RVA infection includes children under 6 months of age (p<0.01). Vomiting was highly associated with RVA infection (72.1%; p<0.001). From the 86 RVA-positive samples, 72 (83.7%) were genotyped. The most prevalent genotype was G1P[8] (34/72; 47.2%), followed by the uncommon G1P[6] (21/72; 29.2%), and G2P[4] (9/72; 12.5%). Only two G-types were found: G1 (60/72; 83.3%) and G2 (11/72; 15.3%). Among the P-genotypes, P[8] was the most prevalent (34/72; 47.2%), followed by P[6] (22/72; 30.6%) and P[4] (9/72; 12.5%). In the phylogenetic trees, the identified G and P-types clustered tightly together and with reference sequences in specific monophyletic groups, with highly significant bootstrap values (≥92%).

CONCLUSION

This pre-vaccination study revealed, for the first time for Bengo province (Angola), the RVA genotype profile, including phylogenetic relationships, and a high RVA detection rate, supporting the immediate introduction of a RVA vaccine in the national immunization programme.

Multiple etiologies of infectious diarrhea and concurrent infections in a pediatric outpatient-based screening study in Odisha, India

BACKGROUND

There are multiple etiologies responsible for infectious gastroenteritis causing acute diarrhea which are often under diagnosed. Also acute diarrhea is one of the major causes of morbidity and mortality among children less than 5 years of age.

METHODS

In our study, fecal samples (n = 130) were collected from children (<5 years) presenting with symptoms of acute diarrhea. Samples were screened for viral, bacterial, and parasitic etiologies. Rotavirus and Adenovirus were screened by immunochromatographic tests. Diarrheagenic Escherichia coli (EPEC, EHEC, STEC, EAEC, O157, O111), Shigella spp., Salmonella spp., Vibrio cholera, Cryptosporidium spp., and Giardia spp. were detected by gene-specific polymerase chain reaction.

RESULTS

Escherichia coli was detected to be the major etiological agent (30.07%) followed by Rotavirus (26.15%), Shigella (23.84%), Adenovirus (4.61%), Cryptosporidium (3.07%), and Giardia (0.77%). Concurrent infections with two or more pathogens were observed in 44 of 130 (33.84%) cases with a predominant incidence particularly in <2-year-old children (65.90%) compared to children of 2-5 years age group (34.09%). An overall result showed significantly higher detection rates among children with diarrhea in both combinations of two as well as three infections concurrently (p = 0.004915 and 0.03917, respectively).

CONCLUSION

Suspecting possible multiple infectious etiologies and diagnosis of the right causative agent(s) can aid in a better pharmacological management of acute childhood diarrhea. It is hypothesized that in cases with concurrent infections the etiological agents might be complementing each other's strategies of pathogenesis resulting in severe diarrhea that could be studied better in experimental infections.