Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND

Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021.

METHODS

The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk-outcome pairs. Pairs were included on the basis of data-driven determination of a risk-outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk-outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk-outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws.

FINDINGS

Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7-9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4-9·2]), smoking (5·7% [4·7-6·8]), low birthweight and short gestation (5·6% [4·8-6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8-6·0]). For younger demographics (ie, those aged 0-4 years and 5-14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9-27·7]) and environmental and occupational risks (decrease of 22·0% [15·5-28·8]), coupled with a 49·4% (42·3-56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9-21·7] for high BMI and 7·9% [3·3-12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6-1·9) for high BMI and 1·3% (1·1-1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4-78·8) for child growth failure and 66·3% (60·2-72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP).

INTERPRETATION

Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions.

FUNDING

Bill & Melinda Gates Foundation.

Parasites burden in peri-urban free-roaming pigs in Gert Sibande District Municipality, Mpumalanga Province, South Africa

BACKGROUND

Parasite infections, unlike regulated animal diseases, do not often receive attention. In fact, parasites are major sources of financial losses in pig enterprises, particularly in subsistence and small-scale pig production systems.

OBJECTIVE

To identify and quantify the prevalence of ecto- and endo-parasites among peri-urban free-roaming pigs (FRP) in Gert Sibande District Municipality (GSDM), Mpumalanga.

METHODS

Pig owners were identified using the snowball sampling method since no sampling frame for FRP farmers exists. Stratified sampling was used to select pigs for sampling for ecto- and endo-parasites. A form was used to record the observations. Pairwise correlation analysis was performed using Stata 15.0. The SPSS V28.0 statistical package was used to perform the chi-square test (X2) to assess the distribution of parasites in different age groups. The prevalence of parasites was assessed in different age groups of pigs using multi-response crosstabs. Multivariate analysis of variance (MANOVA) was used to estimate the marginal mean of parasites according to municipality. Statistical significance was assessed at α ≤ 0.05.

RESULTS

Over 90% (91.2%) of the pigs examined were infested with at least one parasite, including Haematopinus suis, Sarcoptes scabiei, Ascaris suum, Fasciola hepatica, Trichuris suis, Strongylids, Coccidia spp, Moniezia expansa, and Siphonaptera spp. The correlation between Ascaris suum and body condition was weak but statistically significant (r = 0.24; p < 0.05).

CONCLUSION

Policy makers, animal researchers and veterinary services must focus on developing policies, risk communication and community engagement materials, which target pig farmers in peri-urban areas such as Gert Sibande District Municipality, Mpumalanga Province.

Evaluation of antimicrobial usage in companion animals at a Veterinary Teaching Hospital in Nigeria

This study investigated various qualitative and quantitative indices of antimicrobial use (AMU) in companion animals (CAs) at a Veterinary Teaching Hospital (VTH-A) and its annex (VTH- B) from 2019 to 2021. For 694 documented animals, antimicrobial administrations (AADs) were 5, 278 times, of which 98.8% (5217) and 1.2% (61) were in dogs and cats respectively. At the VTH- A, oxytetracycline (1185 times, 22.5%) was mostly administered in dogs and metronidazole (26 times, 0.5%) in cats. Similarly, at VTH- B, oxytetracycline was administered 895 times (17.0%) in dogs while amoxicillin was given 7 times (0.1%) in cats. The prescription diversity (PD) was estimated at 0.73 and 0.82 in VTH-A and VTH-B respectively. The quantity of antimicrobials (AMs) used was 10.1 kg (A, 6.2 kg and B, 3.9 kg). Oxytetracycline administrations and quantity of metronidazole (P < 0.0001) were higher than other Active Ingredients (AIs). Furthermore, 16.5% of AIs were classified as Critically Important Antibiotics (CIA) with the highest priority, while enrofloxacin, ciprofloxacin, and azithromycin fell under the World Health Organisation (WHO) Watch group. The In-Depth Interview (IDI) indicated that the high frequency of oxytetracycline administrations was linked with being the first choice for blood parasite treatment by the clinicians at the hospital. The quantity of metronidazole used was perceived to be higher due to the clinicians' preference for the treatment of acute gastroenteritis, its wider dose range, and the frequency of administration (bi-daily). The study provides baseline data on AMU indices in CAs, for the development of antimicrobial stewardship (AMS) and communication training, and policy modifications to enhance antimicrobial therapy optimization in tertiary veterinary hospital care in Nigeria.

Antimicrobial usage and associated residues and resistance emergence in smallholder beef cattle production systems in Nigeria: A One Health challenge

Livestock intensification has facilitated antimicrobial use (AMU) with consequent antimicrobial resistance (AMR) development. We assessed AMU in beef farms, pathways for residues and resistance dissemination to humans, risk status, residues identification, and drivers for antimicrobial residues and resistance emergence in beef cattle production systems. A cross-sectional survey was conducted in randomly selected beef farms of Northern Nigeria, between 2018 and 2019. Traffic Light model and Disc Diffusion Test were used to assess risk status and determined residues, respectively. Data was analyzed using descriptive statistics and logistic regression models at 95% confidence level. About 92% (n = 608) farmers participated. The majority of farmers managing intensive (78.9%) and semi-intensive (76.6%) farms did not follow antimicrobial dosage instructions. Also, 72.4% and 83.9% of the farmers on intensive and semi-intensive systems, respectively, did not observed withdrawal periods after AMU. Furthermore, 71.5% farmers in intensive and 53.2% in semi-intensive farms used antimicrobials as growth promoters. Antimicrobials frequently used include tetracyclines, sulfonamides and penicillin. Antimicrobial residues and resistance dissemination pathways from beef herds were: consumption of contaminated meat with residues (p = 0.007); contacts with contaminated cattle and fomites (p < 0.001); and contaminated manure and aerosols in farm environment (p = 0.003). Significant drivers of residues and resistance emergence were antimicrobial misuse and overuse (OR = 2.72; 95% CI:1.93-3.83), non-enforcement of laws (OR = 2.98; 95% CI:2.11-4.21), poor education and expertise (OR = 1.52; 95% CI:1.09-2.12), and husbandry management system (OR = 10.24; 95% CI:6.75-15.54). The majority of intensive (63.6%) and semi-intensive (57.63%) farm systems belonged to Class 3 (Red risk) status. Antimicrobial residues were detected in 48.4% intensively and 34.4% semi-intensively managed farms. The study revealed poor practices of AMU in beef cattle production. Many factors were found to influenced antimicrobial residues and resistance occurrence and dissemination. A 'One Health' approach mitigation with adequate sanitation, hygiene, and good biosecurity measures will assure food safety, public and environmental health.

Assessment of knowledge, attitudes and practices relating to brucellosis among cattle farmers, meat handlers and medical professionals in Namibia

BACKGROUND

Brucellosis is a re-emerging zoonosis of significant socio-economic, animal and public health importance. It is principally a foodborne or occupation-associated infection of humans, whose effective control depends on maximum cooperation of high-risk populations.

OBJECTIVES

The study assessed knowledge, attitudes and practices relating to brucellosis among cattle farmers (communal and commercial), meat handlers (abattoir and butchery workers) and medical professionals (nurses and doctors) in Namibia.

METHODS

Between June 2019 and September 2020, self-administered questionnaires and questionnaire interviews were carried out in cattle farmers (n = 264), meat handlers (n = 143) and medical professionals (n = 124) in Namibia.

RESULTS

Overall, 43.50% (231/531) of respondents were aware of brucellosis, with the highest awareness among medical professionals (73.39%, 91/124) and the least in meat handlers (13.99%, 20/143). Awareness of brucellosis was associated with tertiary education (p < 0.001) and the medical profession (p < 0.001). However, most medical professionals (98.39%, 122/124) did not consider brucellosis as a differential diagnosis in cases of persistent febrile illness. A proportion of communal (85.60%) and commercial (71.00%) farmers; abattoir workers (44.40%); butchers (53.50%); nurses (55.60%); and medical doctors (28.00%) consumed raw milk.

CONCLUSIONS

The study identified the purchase of animals of unknown health status; assisting cow delivery; handling of aborted fetuses with no protective wear; consumption of raw milk, homemade cheese, cattle testes and undercooked livers, as risk factors for Brucella infection in cattle and humans. Thus, intensified risk communication, including public health education, is recommended, in particular, among meat handlers and communal farmers, to promote awareness and discourage risky practices.

Semi-Scavenging Poultry as Carriers of Avian Influenza Genes

Ducks are the natural reservoir of influenza A virus and the central host for the avian influenza virus (AIV) subtype H5N1, which is highly pathogenic. Semi-scavenging domestic ducks allow for the reemergence of new influenza subtypes which could be transmitted to humans. We collected 844 cloacal swabs from semi-scavenging ducks inhabiting seven migratory bird sanctuaries of Bangladesh for the molecular detection of avian influenza genes. We detected the matrix gene (M gene) using real-time RT-PCR (RT-qPCR). Subtyping of the AIV-positive samples was performed by RT-qPCR specific for H5, H7, and H9 genes. Out of 844 samples, 21 (2.488%) were positive for AIV. Subtyping of AIV positive samples (n = 21) revealed that nine samples (42.85%) were positive for the H9 subtype, five (23.80%) were positive for H5, and seven (33.33%) were negative for the three genes (H5, H7, and H9). We detected the same genes after propagating the virus in embryonated chicken eggs from positive samples. Semi-scavenging ducks could act as carriers of pathogenic AIV, including the less pathogenic H9 subtype. This can enhance the pathogenicity of the virus in ducks by reassortment. The large dataset presented in our study from seven areas should trigger further studies on AIV prevalence and ecology.

Coronavirus disease 2019 in Africa: why the recent spike in cases?

This chapter assesses the recent cases of COVID-19 pandemic in Africa. COVID-19, a global pandemic, is spreading so fast across all continents with African region not left out of its ravaging and devastating effects. Nigeria, on May 31, 2020, became the first country in West Africa to hit the 10,000 mark of confirmed COVID-19 cases. This recent spike in COVID-19 cases with accompanying increase in the number of fatalities calls for concern. As of July 21, 2020, Nigeria ranked third in Africa, just behind South Africa and Egypt, while the total number of confirmed cases in Africa has increased to 736,288. What would have led to the increasing cases in Africa? We found that poverty, hunger, people's violation of health guidelines, and increase in the number of laboratory tests for suspected COVID-19 cases are responsible for the sudden and sustained rise in cases in the continent.

Lessons Learned From a Large Cross-Border Field Simulation Exercise to Strengthen Emergency Preparedness in East Africa, 2019

Field simulation exercises (FSXs) require substantial time, resources, and organizational experience to plan and implement and are less commonly undertaken than drills or tabletop exercises. Despite this, FSXs provide an opportunity to test the full scope of operational capacities, including coordination across sectors. From June 11 to 14, 2019, the East African Community Secretariat conducted a cross-border FSX at the Namanga One Stop Border Post between the Republic of Kenya and the United Republic of Tanzania. The World Health Organization Department of Health Security Preparedness was the technical lead responsible for developing and coordinating the exercise. The purpose of the FSX was to assess and further enhance multisectoral outbreak preparedness and response in the East Africa Region, using a One Health approach. Participants included staff from the transport, police and customs, public health, animal health, and food inspection sectors. This was the first FSX of this scale, magnitude, and complexity to be conducted in East Africa for the purpose of strengthening emergency preparedness capacities. The FSX provided an opportunity for individual learning and national capacity strengthening in emergency management and response coordination. In this article, we describe lessons learned and propose recommendations relevant to FSX design, management, and organization to inform future field exercises.

Prevalence and risk of staphylococcal and coliform carcass contamination of chickens slaughtered in the informal market in Gauteng, South Africa

Purpose

The primary objective was to determine the prevalence of indicator microorganisms [Staphylococcus aureus, non-S. aureus staphylococci (NSAS), coliforms and aerobic bacteria] for contamination of chicken carcasses, carcass drip and rinse water from the informal chicken market in Gauteng, South Africa.

Design/methodology/approach

Chicken swabs, chicken drips and rinse waters were collected from 151 chickens from 47 random outlets. Pre-tested questionnaires were administered to capture the risk factors for bacterial contamination. Standard microbiological procedures were conducted for isolation and enumeration of target bacteria.

Findings

NSAS (64% and 41%) and S. aureus (12% and 31%) were prevalent on carcasses and in carcass drip respectively. Coliforms (62%) and aerobic bacteria (85%) were detected in rinse water. Significant risk factors for contamination of carcasses with NSAS, S. aureus and coliform organisms were: evisceration of chickens on the same location used for sale, cleaning of display counter with dirty clothes/wipes, holding of differently sourced chickens in the same cage prior to slaughter, not cleaning the display table/counter and hands at all, washing knives in rinse water, high turnover of daily slaughter and length of time to display chickens.

Research limitations/implications

The limitations of this research were the limited geographical coverage and small sample size.

Practical implications

The isolation of these indicator microorganisms suggests the potential presence of other chicken-borne pathogens not tested for in the study.

Social implications

The findings serve to inform policy on public health and street-vended food and can guide control on good sanitary practices.

Originality/value

This is the first comprehensive report on ready to eat chickens from the informal markets in Gauteng, South Africa.

Impact of Dose and Route of administration on Antibody Responses of Chickens Inoculated with inactivated Avian Influenza H5 Vaccine.. [DOI: 10.21203/rs.3.rs-158047/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Avian influenza viruses (AIV) poses significant threats to human and animal lives globally, and in spite of availability of vaccines, only few studies have established the role of passively acquired antibodies in the protection of chickens in sub Saharan Africa. The present study evaluated the influence of dose and route of administration of AI H5 inactivated vaccine on the humoral immune response of ISA brown chickens. Ninety “one-day-old” chickens were purchased from three major commercial hatcheries A, B and C (n = 30 chicks per hatchery), respectively. Results showed significant differences (P < 0.001) in the mean antibody titre levels at day 21 of age between chicks from hatcheries C (2,205.0 ± 409.1) and A (57.7 ± 49.9) at 21 days of age when either 0.2 ml or 0.5 ml of the vaccine was administered IM or SC. In addition, there were intra- and inter dose significant differences (P < 0.001) between the chicks at 21, 28, 35 and 42 days of age. Furthermore, intra- and inter route significant differences (P < 0.001) were detected between the chicks at 21 and 35 days of age. Overall, the AI H5 vaccine studied had variable outcomes and poorly immunogenic. Further studies should be conducted to characterize the T- and B-lymphocytes in chickens post AI H5 vaccines administration, and evaluate the sequence homologies between imported AI H5 vaccines and circulating AIV strains in Nigeria.

A literature review of the use of environmental sampling in the surveillance of avian influenza viruses

This literature review provides an overview of use of environmental samples (ES) such as faeces, water, air, mud and swabs of surfaces in avian influenza (AI) surveillance programs, focussing on effectiveness, advantages and gaps in knowledge. ES have been used effectively for AI surveillance since the 1970s. Results from ES have enhanced understanding of the biology of AI viruses in wild birds and in markets, of links between human and avian influenza, provided early warning of viral incursions, allowed assessment of effectiveness of control and preventive measures, and assisted epidemiological studies in outbreaks, both avian and human. Variation exists in the methods and protocols used, and no internationally recognized guidelines exist on the use of ES and data management. Few studies have performed direct comparisons of ES versus live bird samples (LBS). Results reported so far demonstrate reliance on ES will not be sufficient to detect virus in all cases when it is present, especially when the prevalence of infection/contamination is low. Multiple sample types should be collected. In live bird markets, ES from processing/selling areas are more likely to test positive than samples from bird holding areas. When compared to LBS, ES is considered a cost-effective, simple, rapid, flexible, convenient and acceptable way of achieving surveillance objectives. As a non-invasive technique, it can minimize effects on animal welfare and trade in markets and reduce impacts on wild bird communities. Some limitations of environmental sampling methods have been identified, such as the loss of species-specific or information on the source of virus, and taxonomic-level analyses, unless additional methods are applied. Some studies employing ES have not provided detailed methods. In others, where ES and LBS are collected from the same site, positive results have not been assigned to specific sample types. These gaps should be remedied in future studies.

Systematic review and meta-analysis of veterinary-related occupational exposures to hazards

Understanding hazards within the veterinary profession is critical for developing strategies to ensure the health and safety of personnel in the work environment. This study was conducted to systematically review and synthesize data on reported risks within veterinary workplaces. A systematic review of published data on occupational hazards and associated risk factors were searched within three database platforms namely PubMed, Ebscohost, and Google scholar. To determine the proportion estimates of hazards and pooled odds ratio, two random-effects meta-analysis were performed. For the biological, chemical and physical hazards, the pooled proportion estimates were 17% (95% CI: 15.0-19.0, p < 0.001), 7.0% (95% CI: 6.0-9.0%, p < 0.001) and 65.0% (95% CI: 39.0-91.0%, p < 0.001) respectively. A pooled odds ratio indicated the risk of exposures to physical (OR=1.012, 95% CI: 1.008-1.017, p < 0.001) and biological hazards (OR=2.07, 95% CI: 1.70-2.52, p <0.001) increased when working or in contact with animals. The review has provided a better understanding of occupational health and safety status of veterinarians and gaps within the developing countries. This evidence calls for policy formulation and implementation to reduce the risks of exposures to all forms of occupational-related hazards in veterinary workplaces.

Assessment of the Biorisk Status of Veterinary Laboratories in Southwest Nigeria: Application of the Food and Agriculture Organization Laboratory Mapping Tool-Safety Module

Introduction

Because of the nature of work conducted in veterinary laboratories and potential exposures to pathogenic microorganisms, good laboratory practices, risk assessments, biosafety, and biosecurity capacity is becoming vital. In this study, the Food and Agriculture Organization Laboratory Mapping Tool-Safety Module was applied to demonstrate its practical implementation in the assessment of biosafety and biosecurity statuses of veterinary laboratories in Nigeria.

Methods

The Laboratory Mapping Tool-Safety Module, a standardized questionnaire, systematically and semiquantitatively gathered data on 98 subcategories covering 4 areas of biosafety and biosecurity capabilities: administrative, operational, engineering, and personal protective equipment.

Results

Overall, the various areas and categories covered by the Laboratory Mapping Tool-Safety Module were weak across the board, with a mean performance of 19.5% (95% confidence interval, 14.0%-25.1%; range, 0.8%-29.6%). The weakest functionality was in emergency preparedness (0.8%; ie, emergency responses and exercises such as fire drills, spill cleanup, and biological spill kit availability). Also, many laboratories were deficient in metrology procedures, biosafety cabinets, chemical hazard containment, regular maintenance and external calibration procedures for laboratory equipment, and personnel health and safety. However, a few functionalities within individual laboratories scored above average (50%), for example, a university microbiology laboratory animal facility (100%). Interlaboratory comparison indicated that biosafety and biosecurity performance was similar across laboratories (P = .07) and did not vary by location (P = .37).

Conclusions

Significant biosafety and biosecurity improvements are needed to guarantee the health and safety of workers and the global community, efficient responses to infectious disease containment, and compliance with the Global Health Security Agenda.

A retrospective sero-epidemiological survey of bovine brucellosis on commercial and communal farming systems in Namibia from 2004 to 2018

Cattle production is the major livestock production activity and the mainstay of Namibia's economy. Sustained beef exports are contingent on a sound sanitary environment where diseases such as brucellosis are under control. In this retrospective study, 49,718 bovine brucellosis testing results from 2004 to 2018 were analyzed to determine the proportion of sero-positive cattle and herds, and the spatial distribution of positive reactors from commercial and communal areas. In total, 244 positive reactors were identified based on the Rose Bengal Test (RBT) and the Complement Fixation Test (CFT) in series, giving an overall proportion of infected animals of 0.49% (244/49,718; 95% CI, 0.43-0.56%) and an overall proportion of infected herds of 9.26% (78/842; 95% CI, 7.49-11.41%). There was a higher proportion of sero-positive communal herds (33.09%) and cattle (10.27%) than commercial herds (4.67%) and cattle (0.24%; p < 0.05). Annually, the proportion of positive reactors was 0-1.37% in the commercial area and 0-52.38% in the communal areas, with a clear decline in positive reactors in the communal areas. Within the commercial sector, the proportion of positive reactor dairy, beef, and export cattle was 0.19% (51/27,067; 95% CI, 0.14-0.25%), 0.30% (48/16,098; 95% CI, 0.22-0.40%), and 0.33% (16/4811; 95% CI, 0.20-0.54%), respectively. Abortions were found to be the major reason for Brucella testing in the communal areas. About 12.65% (96/759) of abortion-linked sera tested positive in the communal areas, but none were positive in beef or dairy cattle. Widespread vaccination of cattle and robust planned surveillance is recommended to reduce the incidence of the disease, its associated production losses and public health risk.

Seroepidemiology of Leptospira infection in slaughtered cattle in Gauteng province, South Africa

Leptospirosis is an important economical disease of livestock globally, especially in Asia, the Caribbean, and the African continent. Its presence has been reported in a wide range of livestock. However, information on leptospirosis in South Africa is scanty. We conducted a cross-sectional study in 11 randomly selected abattoirs to determine the seroprevalence and risk factors for leptospirosis in slaughtered cattle in Gauteng province, South Africa. During abattoir visits to selected abattoirs, blood samples were collected from 199 cattle and demographic data obtained on the slaughtered animals. The microscopic agglutination test (MAT) was performed on all sera using a 26-serotype panel using cutoff titer ≥ 1:100. Animal- and abattoir-level risk factors were investigated for their association with seropositivity for leptospirosis. The seroprevalence of leptospirosis in the cattle sampled was 27.6% (55/199). The predominant serogroups detected in seropositive cattle were Sejroe (sv. Hardjo) (38.2%) and Mini sv. Szwajizak) (14.5%) but low to Canicola (sv. Canicola) (1.8%) and Pomona (sv. Pomona) (1.8%). The differences were statistically significant (P < 0.05). Of the five variables investigated, only one (abattoirs) had statistically significantly (P < 0.001) differences in the seroprevalence of leptospirosis among abattoirs. The study documented for the first time in South Africa, the occurrence of serogroups Sejroe (Hardjo bovis strain lely 607), Tarassovi, Hebdomadis, and Medanensis in slaughtered cattle. It was concluded that six of the nine serovars (representing seven serogroups) of Leptospira spp. circulating in cattle population in South Africa are not vaccine serogroups. The clinical, diagnostic, and public health importance of the findings cannot be ignored.

Assessing the Zero Hunger Target Readiness in Africa in the Face of COVID-19 Pandemic

<p>Sustainable Development Goal 2 (SDG 2) is hinged on achieving zero hunger target globally by 2030. Many developing countries, especially African countries, are challenged with extreme hunger that are often caused or compounded by bad governance, conflicts and climate change. In this paper, we assess Africa’s readiness towards attaining the zero hunger target by 2030 in the face of COVID-19 pandemic. Patterns of Global Hunger Index (GHI) and each of its indicators across Africa are compared before the pandemic (2000-2019). The effect of the pandemic on the hunger situation in Africa is discussed by highlighting the mitigating measures put in place by selected African governments. We have found that most African countries have recorded steady reduction in their child mortality rates but high prevalence of undernourishment, stunting and child wasting indicates significant challenges hampering the achievement of the zero hunger target. The study recommends that African governments should prioritize sustainable agricultural practices and give serious attention to the formulation and implementation of policies that reduce hunger against the COVID-19 pandemic.</p>

Preventing zoonotic influenza H5N1 in human: Pictorial versus literal health communication methods

Outbreaks of avian influenza H5N1 in poultry occurred in Africa's poultry and 16 countries have reported human infections globally. Intensified human-animal interactions necessitate correct communication of health messages to reduce zoonotic infection. This work was done to determine differences between pictorial and literal health education communication. Cross-sectional survey using literal and pictorial questionnaires in LBMs and poultry farms was carried out among respondents based on matching criteria. Responses were scored and analysed with probability of independence using Chi square test and pairwise correlation. The degree of knowledge of clinical signs in birds, species affected, communication means and biosecurity were good, that of the post-mortem signs was poor with increasing potentials of human exposure to virus-rich visceral tissues from slaughtered sick birds. Marked differences exist for the various items listed within each knowledge field, the odds of having correct responses from pictorial were better than with literal respondents. Risky practices were still practised in the LBMs despite the good degree of knowledge of hygiene and biosecurity. Knowledge and implementation does not always correlate and pictorial representation out surpasses literal method in communicating potential zoonotic H5N1 influenza A infection to the undiscerning public.

Farmers' Perceptions and Drivers of Antimicrobial Use and Abuse in Commercial Pig Production, Ogun State, Nigeria

Antimicrobial resistance (AMR) in humans has been linked to non-judicious antimicrobial use (AMU) in food animals. To develop antimicrobial stewardship plans (AMSPs) for pig farmers, there is the need to understand the current status of AMU and the driving factors in the industry. Data on AMU, farmers' perceptions of associated drivers, and biosecurity were collected through a mixed-method study design with focus group discussions (FGDs) and questionnaire-based interviews. Antimicrobials (AMs) were mainly used for therapeutic and prophylactic purposes. Common AMs used were tetracycline (78.8%), gentamycin (53.8%), and tylosin (52.5%). Perceived drivers of AMU were linked to economic benefits, farmers' previous experiences, sick animals, expensive veterinary services, easy accessibility to over-the-counter drugs, poor farm practices, and poor disease prevention strategies. AMU was poor (average 40.2%), while knowledge on AMs and implications for animal and human health was considered averagely satisfactory (56.4%). The biosecurity level was also satisfactory (53.0%) and significantly associated with having a written farm health plan (p = 0.035). Good AMU was found to be strongly associated with farmers' use of veterinary services (p = 0.001). Diverse factors drive antimicrobial use among pig farmers in Ogun State, and these could be addressed by providing continuing education on antimicrobial stewardship and best farm practices.

Expanding beyond zoonoses: the benefits of a national One Health coordination mechanism to address antimicrobial resistance and other shared health threats at the human-animal-environment interface in Kenya

In order to manage global and transnational health threats at the human- animal-environment interface, a multisectoral One Health approach is required. Threats of this nature that require a One Health approach include, but are not limited to, emerging, endemic and re-emerging zoonotic diseases, food safety, antimicrobial resistance (AMR), vector-borne and neglected infectious diseases, toxicosis and pesticides. Relevant Kenyan authorities formally institutionalised One Health in 2011 through the establishment of the Zoonotic Disease Unit (ZDU) and its advisory group, the Zoonoses Technical Group. At that time, the One Health agenda focused on zoonotic diseases. As the issue of AMR began to gain traction globally, a One Health approach to its management was advocated in Kenya in 2015. This paper summarises a series of interviews (with respondents and key informants) that describe how AMR institutionalisation evolved in Kenya. It also examines how responses to other health threats at the human-animal- environment interface were coordinated and used to identify gaps and make recommendations to improve One Health coordination at the national level in Kenya. Results showed that the road to the institutionalisation of AMR through the National Action Plan on Prevention and Containment of Antimicrobial Resistance, 2017-2022 and a formally launched One Health coordination mechanism, the National Antimicrobial Stewardship Interagency Committee (NASIC), took ten years. Moreover, supplementary actions are still needed to further strengthen AMR coordination. In addition to the ZDU and NASIC, Kenya has established two other formal multisectoral and multidisciplinary coordination structures, one for aflatoxicosis and the other for health threats associated with pesticide use. The country has four distinct and separate One Health coordination mechanisms: for zoonoses, for AMR, for aflatoxicosis and for the health threats associated with pesticide use. The main gap lies in the lack of overall coordination between these topic-specific structures. An overall coordination mechanism for all One Health issues is therefore needed to improve synergy and complementarity. None of the topic-specific mechanisms plays a critical role in the policy development process, institutionalisation or implementation of activities related to the other topic areas. The authors recommend renaming the ZDU as the One Health Office, and expanding it to include AMR and food safety teams, and their associated technical working groups. Through this restructuring, the One Health Office would become an umbrella organisation dealing with all four issues mentioned above. Based on Kenya's experience, the authors recommend that other countries also consider expanding the scope of multisectoral One Health coordination mechanisms to include other shared health threats.

Field evaluation of common poultry viral vaccinesin Egypt: a need for reassessment of the vaccine value chain

Egypt has a large traditional and exotic poultry sector which is challenged regularly by poultry diseases in endemic and epidemic proportions. The household poultry in particular is a source of livelihoods and employment for millions of low income citizens. Highly pathogenic avian influenza (HPAI) H5N1 and Newcastle disease are the most important poultry diseases in this sector. Whereas poultry vaccines are available to reduce the incidence of disease in Egypt, their effectiveness is doubtful. We conducted a biological evaluation of selected viral vaccines of poultry in three governorates in Egypt. Fifty‑four percent of the vaccines had reduced vaccine titres and the effect of secondary vaccine distributions was associated with the observed vaccine titres. External contamination was observed in some vaccines and break in cold chain was reported. Whereas no vaccine distributor used purpose‑built vaccine refrigerator, none also had prescribed protocol for vaccine handling or kept record of vaccine. There is a need to review vaccine handling procedure, monitor of vaccine cold chain more critically and review the whole chain that support vaccine distributions in Egypt.

Antimicrobial Drug Administration and Antimicrobial Resistance of Salmonella Isolates Originating from the Broiler Production Value Chain in Nigeria

Salmonella is among the pathogens on the high global priority lists for monitoring for studies on the discovery of new antimicrobials and understanding of how antimicrobial resistance (AMR) develops. AMR in connection with antibiotic usage patterns has been considered as a strong factor and contributor to the AMR pool. The purposes of use, pattern of antimicrobial drug administration, as well as the prevalence of AMR in Salmonella originating from the Nigeria broiler production value chain (NBPVC) was explored. A well-structured questionnaire on antimicrobial usage (n = 181) was used for sampling that focused on 21 antimicrobials from 151 locations. Simultaneously, AMR testing for 18 commonly used antimicrobials on Salmonella in humans was also carried out. Antimicrobial resistance Salmonella spp. were isolated in 23% of the samples (261 of 1135 samples from the broiler input, products, and the environment) using modified ISO 6579 and invA PCR protocols. Over 80% of the antimicrobials used in the NBPVC were administered without a veterinarian prescription. Prevalence of antimicrobial administration without prescription were as follows: live-bird-market (100%), hatchery (86.7%), grow-out-farm (75%), and breeder (66.7%). Widespread prophylactic and metaphylactic use of antimicrobials were recorded with the highest use seen for enrofloxacin (63% and 24%), tetracycline (58% and 33%), and erythromycin (50% and 17%). Antimicrobial resistance was highest for flumequine (100%), penicillin (95%), and perfloxacin (89%). High levels of use without laboratory support of a newer generation of a class of antibiotics suspected to confer high resistance on older generations of the same class (quinolones) was observed.

Antimicrobial Resistance in Food Animals and the Environment in Nigeria: A Review

Antimicrobial resistance (AMR) has emerged as a global health threat, which has elicited a high-level political declaration at the United Nations General Assembly, 2016. In response, member countries agreed to pay greater attention to the surveillance and implementation of antimicrobial stewardship. The Nigeria Centre for Disease Control called for a review of AMR in Nigeria using a &ldquo;One Health approach&rdquo;. As anecdotal evidence suggests that food animal health and production rely heavily on antimicrobials, it becomes imperative to understand AMR trends in food animals and the environment. We reviewed previous studies to curate data and evaluate the contributions of food animals and the environment (2000⁻2016) to the AMR burden in Nigeria using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart focused on three areas: Antimicrobial resistance, residues, and antiseptics studies. Only one of the 48 antimicrobial studies did not report multidrug resistance. At least 18 bacterial spp. were found to be resistant to various locally available antimicrobials. All 16 residue studies reported high levels of drug residues either in the form of prevalence or concentration above the recommended international limit. Fourteen different &ldquo;resistotypes&rdquo; were found in some commonly used antiseptics. High levels of residues and AMR were found in food animals destined for the human food chain. High levels of residues and antimicrobials discharged into environments sustain the AMR pool. These had evolved into potential public health challenges that need attention. These findings constitute public health threats for Nigeria&rsquo;s teeming population and require attention.

Mapping Potential Amplification and Transmission Hotspots for MERS-CoV, Kenya

Dromedary camels have been implicated consistently as the source of Middle East respiratory syndrome coronavirus (MERS-CoV) human infections and attention to prevent and control it has focused on camels. To understanding the epidemiological role of camels in the transmission of MERS-CoV, we utilized an iterative empirical process in Geographic Information System (GIS) to identify and qualify potential hotspots for maintenance and circulation of MERS-CoV, and produced risk-based surveillance sites in Kenya. Data on camel population and distribution were used to develop camel density map, while camel farming system was defined using multi-factorial criteria including the agro-ecological zones (AEZs), production and marketing practices. Primary and secondary MERS-CoV seroprevalence data from specific sites were analyzed, and location-based prevalence matching with camel densities was conducted. High-risk convergence points (migration zones, trade routes, camel markets, slaughter slabs) were profiled and frequent cross-border camel movement mapped. Results showed that high camel-dense areas and interaction (markets and migration zones) were potential hotspot for transmission and spread. Cross-border contacts occurred with in-migrated herds at hotspot locations. AEZ differential did not influence risk distribution and plausible risk factors for spatial MERS-CoV hotspots were camel densities, previous cases of MERS-CoV, high seroprevalence and points of camel convergences. Although Kenyan camels are predisposed to MERS-CoV, no shedding is documented to date. These potential hotspots, determined using anthropogenic, system and trade characterizations should guide selection of sampling/surveillance sites, high-risk locations, critical areas for interventions and policy development in Kenya, as well as instigate further virological examination of camels.

Sero-prevalence and intrinsic factors associated with Brucella infection in food animals slaughtered at abattoirs in Abuja, Nigeria

BACKGROUND

Brucellosis, a neglected tropical food-borne zoonotic disease, has a negative impact on both animal and human health as well as tremendous socio-economic impact in developing countries where rural income relies largely on livestock breeding and dairy products. It is endemic in the animal population in Nigeria and is a recognized occupational hazard. This work was done to establish the sero-prevalence and predisposing factors of food animals in Abuja, Nigeria to Brucella infection.

RESULTS

Of 376 cattle, 203 sheep and 260 goats screened, 21 (5.6%); 19 (9.4%); 51 (19.6%) were positive, respectively for brucellosis with Rose Bengal Plate Test, and 2 (0.5%); 4 (2.0%); 10 (3.8%), respectively with c-ELISA. The likelihood of acquiring Brucella infection was higher among the Red Sokoto breed of goats compared to other breeds of goats (p = 0.05).

CONCLUSION

This study showed that the prevalence of Brucella infection was low in food animals slaughtered at abattoirs in Abuja. However, of all animals screened, seropositivity to Brucella infection was highest in goats with Red Sokoto breed of goats more likely to acquire the disease when compared to other breeds.

Public health concerns of highly pathogenic avian influenza H5N1 endemicity in Africa

Highly pathogenic avian influenza virus (HPAIV) H5N1 was first officially reported in Africa in 2006; thereafter this virus has spread rapidly from Nigeria to 11 other African countries. This study was aimed at utilizing data from confirmed laboratory reports to carry out a qualitative evaluation of the factors responsible for HPAI H5N1 persistence in Africa and the public health implications; and to suggest appropriate control measures. Relevant publications were sought from data banks and repositories of FAO, OIE, WHO, and Google scholars. Substantiated data on HPAI H5N1 outbreaks in poultry in Africa and in humans across the world were mined. HPAI H5N1 affects poultry and human populations, with Egypt having highest human cases (346) globally. Nigeria had a reinfection from 2014 to 2015, with outbreaks in Côte d'Ivoire, Ghana, Niger, Nigeria, and Burkina Faso throughout 2016 unabated. The persistence of this virus in Africa is attributed to the survivability of HPAIV, ability to evolve other subtypes through genetic reassortment, poor biosecurity compliance at the live bird markets and poultry farms, husbandry methods and multispecies livestock farming, poultry vaccinations, and continuous shedding of HPAIV, transboundary transmission of HPAIV through poultry trades; and transcontinental migratory birds. There is, therefore, the need for African nations to realistically reassess their status, through regular surveillance and be transparent with HPAI H5N1 outbreak data. Also, it is important to have an understanding of HPAIV migration dynamics which will be helpful in epidemiological modeling, disease prevention, control and eradication measures.

Cross-sectional surveillance of Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels and other mammals in Egypt, August 2015 to January 2016

A cross-sectional study was conducted in Egypt to determine the prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) in imported and resident camels and bats, as well as to assess possible transmission of the virus to domestic ruminants and equines. A total of 1,031 sera, 1,078 nasal swabs, 13 rectal swabs, and 38 milk samples were collected from 1,078 camels in different types of sites. In addition, 145 domestic animals and 109 bats were sampled. Overall, of 1,031 serologically-tested camels, 871 (84.5%) had MERS-CoV neutralising antibodies. Seroprevalence was significantly higher in imported (614/692; 88.7%) than resident camels (257/339; 5.8%) (p < 0.05). Camels from Sudan (543/594; 91.4%) had a higher seroprevalence than those from East Africa (71/98; 72.4%) (p < 0.05). Sampling site and age were also associated with MERS-CoV seroprevalence (p < 0.05). All tested samples from domestic animals and bats were negative for MERS-CoV antibodies except one sheep sample which showed a 1:640 titre. Of 1,078 camels, 41 (3.8%) were positive for MERS-CoV genetic material. Sequences obtained were not found to cluster with clade A or B MERS-CoV sequences and were genetically diverse. The presence of neutralising antibodies in one sheep apparently in contact with seropositive camels calls for further studies on domestic animals in contact with camels.

Protective Efficacy of Recombinant Turkey Herpes Virus (rHVT-H5) and Inactivated H5N1 Vaccines in Commercial Mulard Ducks against the Highly Pathogenic Avian Influenza (HPAI) H5N1 Clade 2.2.1 Virus

In Egypt, ducks kept for commercial purposes constitute the second highest poultry population, at 150 million ducks/year. Hence, ducks play an important role in the introduction and transmission of avian influenza (AI) in the Egyptian poultry population. Attempts to control outbreaks include the use of vaccines, which have varying levels of efficacy and failure. To date, the effects of vaccine efficacy has rarely been determined in ducks. In this study, we evaluated the protective efficacy of a live recombinant vector vaccine based on a turkey Herpes Virus (HVT) expressing the H5 gene from a clade 2.2 H5N1 HPAIV strain (A/Swan/Hungary/499/2006) (rHVT-H5) and a bivalent inactivated H5N1 vaccine prepared from clade 2.2.1 and 2.2.1.1 H5N1 seeds in Mulard ducks. A 0.3ml/dose subcutaneous injection of rHVT-H5 vaccine was administered to one-day-old ducklings (D1) and another 0.5ml/dose subcutaneous injection of the inactivated MEFLUVAC was administered at 7 days (D7). Four separate challenge experiments were conducted at Days 21, 28, 35 and 42, in which all the vaccinated ducks were challenged with 106EID50/duck of H5N1 HPAI virus (A/chicken/Egypt/128s/2012(H5N1) (clade 2.2.1) via intranasal inoculation. Maternal-derived antibody regression and post-vaccination antibody immune responses were monitored weekly. Ducks vaccinated at 21, 28, 35 and 42 days with the rHVT-H5 and MEFLUVAC vaccines were protected against mortality (80%, 80%, 90% and 90%) and (50%, 70%, 80% and 90%) respectively, against challenges with the H5N1 HPAI virus. The amount of viral shedding and shedding rates were lower in the rHVT-H5 vaccine groups than in the MEFLUVAC groups only in the first two challenge experiments. However, the non-vaccinated groups shed significantly more of the virus than the vaccinated groups. Both rHVT-H5 and MEFLUVAC provide early protection, and rHVT-H5 vaccine in particular provides protection against HPAI challenge.

Descriptive analyses and risk of death due to Ebola Virus Disease, West Africa, 2014

INTRODUCTION

Since the first case of Ebola virus disease (EVD) in Guinea in 2013, major outbreaks have been reported in West Africa.

METHODOLOGY

Cases and fatalities of EVD caused by Zaire Ebola virus (ZEBOV) were evaluated, and the risks of dying in the general population and in healthcare workers were assessed.

RESULTS

The case fatality rate estimated for EVD was 76.4% in 20 studies. Cumulative proportion of fatal cases in West Africa was 42.9%, 30.1%, and 64.2% in Liberia, Sierra Leone, and Guinea, respectively. The proportion of total deaths in Liberia, Sierra Leone, and Guinea was 42.5%, 35.8%, and 21.6%, respectively. Healthcare workers were at higher risk of dying compared with the general public, and the same applied to intense transmission countries and to countries with sufficient bed capacities. The declaration of a health emergency "out-of-control" situation by the World Health Organization on 8 August 2014 reduced the risk of death among patients. Factors including deplorable healthcare delivery infrastructure in war-ravaged regions of Africa, the impotence of governments to enforce public health regulations, and the loss of confidence in public healthcare delivery programs were key among others factors that enhanced the spread and magnitude of outbreaks.

CONCLUSIONS

The findings underscore the need for an overall re-appraisal of the healthcare systems in African countries and the ability to cope with widespread epidemic challenges. Outbreaks like that of Ebola diseases should be handled not just as a medical emergency but also a socio-economic problem with significant negative economic impacts.

Development of Disease-specific, Context-specific Surveillance Models: Avian Influenza (H5N1)-Related Risks and Behaviours in African Countries

Avian influenza virus (H5N1) is a rapidly disseminating infection that affects poultry and, potentially, humans. Because the avian virus has already adapted to several mammalian species, decreasing the rate of avian-mammalian contacts is critical to diminish the chances of a total adaptation of H5N1 to humans. To prevent the pandemic such adaptation could facilitate, a biology-specific disease surveillance model is needed, which should also consider geographical and socio-cultural factors. Here, we conceptualized a surveillance model meant to capture H5N1-related biological and cultural aspects, which included food processing, trade and cooking-related practices, as well as incentives (or disincentives) for desirable behaviours. This proof of concept was tested with data collected from 378 Egyptian and Nigerian sites (local [backyard] producers/live bird markets/village abattoirs/commercial abattoirs and veterinary agencies). Findings revealed numerous opportunities for pathogens to disseminate, as well as lack of incentives to adopt preventive measures, and factors that promoted epidemic dissemination. Supporting such observations, the estimated risk for H5N1-related human mortality was higher than previously reported. The need for multidimensional disease surveillance models, which may detect risks at higher levels than models that only measure one factor or outcome, was supported. To develop efficient surveillance systems, interactions should be captured, which include but exceed biological factors. This low-cost and easily implementable model, if conducted over time, may identify focal instances where tailored policies may diminish both endemicity and the total adaptation of H5N1 to the human species.

Transmission dynamics and control of Ebola virus disease outbreak in Nigeria, July to September 2014

We analyse up-to-date epidemiological data of the Ebola virus disease outbreak in Nigeria as of 1 October 2014 in order to estimate the case fatality rate, the proportion of healthcare workers infected and the transmission tree. We also model the impact of control interventions on the size of the epidemic. Results indicate that Nigeria’s quick and forceful implementation of control interventions was determinant in controlling the outbreak rapidly and avoiding a far worse scenario in this country.

Predictors of death and production performance of layer chickens in opened and sealed pens in a tropical savannah environment

BACKGROUND

Layer chickens are exposed to high risks of production losses and mortality with impact on farm profitability. The harsh tropical climate and severe disease outbreaks, poor biosecurity, sub-minimal vaccination and treatment protocols, poor management practices, poor chick quality, feed-associated causes, and unintended accidents oftentimes aggravate mortality and negatively affect egg production. The objectives of this study were to estimate the probability of survival and evaluate risk factors for death under different intensive housing conditions in a tropical climate, and to assess the production performance in the housing systems.

RESULTS

Daily mean mortality percentages and egg production figures were significantly lower and higher in the sealed pens and open houses (P < 0. 001) respectively. The total mean feed consumption/bird/day was similar for the open sided and sealed pens but the mean feed quantity per egg produce was significantly lower in the sealed pens ((P < 0.005). Seasons differently impacted on mortality with the hot-dry season producing significantly higher risk of mortality (61 times) and reduced egg production. Other parameters also differed except the egg production during the cold-dry season. Layers in sealed pens appear to have higher probability of survival and the Kaplan-Meir survival curves differed for each pen; ≥ 78 weeks old layer have higher probability of survival compared with the younger chickens and the 19-38 weeks age category are at highest risk of death (P < 0.001). The hazard-ratio for mortality of layers raised in sealed pens was 0.568 (56.8%).

CONCLUSION

Reasons for spiked mortality in layer chickens may not always be associated with disease. Hot-dry climatic environment is associated with heat stress, waning immunity and inefficient feed usage and increase probability of death with reduced egg production; usage of environmentally controlled building in conditions where environmental temperature may rise significantly above 25°C will reduce this impact. Since younger birds (19-38 weeks) are at higher risk of death due to stress of coming into production, management changes and diseases, critical implementation of protocols that will reduce death at this precarious period becomes mandatory. Whether older chickens' better protection from death is associated with many prophylactic and metaphylactic regimen of medications/vaccination will need further investigation.

Molecular diagnosis of African Swine Fever by a new real-time PCR using universal probe library

A highly sensitive and specific real-time PCR method was developed for the reliable and rapid detection of African swine fever virus (ASFV). The method uses a commercial Universal Probe Library (UPL) probe combined with a specifically designed primer set to amplify an ASFV DNA fragment within the VP72 coding genome region. The detection range of the optimized UPL PCR technique was confirmed by analysis of a large panel (n = 46) of ASFV isolates, belonging to 19 of the 22 viral p72 genotypes described. No amplification signal was observed when closely clinically related viruses, such as classical swine fever, or other porcine pathogens were tested by this assay. The detection limit of the UPL PCR method was established below 18 DNA copies. Validation experiments using an extensive collection of field porcine and tick samples (n = 260), coming from Eastern and Western African regions affected by ASF, demonstrated that the UPL PCR technique was able to detect over 10% more positive samples than the real-time TaqMan PCR test recommended in the OIE manual, confirming its superior diagnostic sensitivity. Clinical material collected during experimental infections with different ASFV p72 genotypes was useful for assuring both the capacity of the UPL PCR for an early viral DNA detection and the competence of the technique to be applied in any ASF diagnostic target sample. The reliability and robustness of the UPL PCR was finally verified with a panel of ASFV-infected clinical samples which was repeatedly tested at different times. Additionally, an internal control PCR assay was also developed and standardized using UPL probes within the endogenous β-actin gene. Finally, the complete study offers a new validated real-time PCR technique, by means of a standardized commercial probe, providing a simple, rapid and affordable test, which is ready for application in the routine diagnosis of ASF.

Epidemic protection zones: centred on cases or based on connectivity?

When an exotic infectious disease invades a susceptible environment, protection zones are enforced. Historically, such zones have been shaped as circles of equal radius (ER), centred on the location of infected premises. Because the ER policy seems to assume that epidemic dissemination is driven by a similar number of secondary cases generated per primary case, it does not consider whether local features, such as connectivity, influence epidemic dispersal. Here we explored the efficacy of ER protection zones. By generating a geographically explicit scenario that mimicked an actual epidemic, we created protection zones of different geometry, comparing the cost-benefit estimates of ER protection zones to a set of alternatives, which considered a pre-existing connecting network (CN) - the road network. The hypothesis of similar number of cases per ER circle was not substantiated: the number of units at risk per circle differed up to four times among ER circles. Findings also showed that even a small area (of <115 km(2) ) revealed network properties. Because the CN policy required 20% less area to be protected than the ER policy, and the CN-based protection zone included a 23.8% greater density of units at risk/km(2) than the ER-based alternative, findings supported the view that protection zones are likely to be less costly and more effective if they consider connecting structures, such as road, railroad and/or river networks. The analysis of local geographical factors (contacts, vectors and connectivity) may optimize the efficacy of control measures against epidemics.

The cost-benefit of biosecurity measures on infectious diseases in the Egyptian household poultry

Increased animal intensification presents with increasing risks of animal diseases. The Egyptian household poultry is peculiar in its management style and housing and this present with particular challenges of risk of infection to both the flock and humans. Biosecurity remains one of the most important means of reducing risks of infection in the household poultry, however not much information is available to support its feasibility at the household level of production. In this study financial feasibilities of biosecurity were modeled and evaluated based on certain production parameters. Risks of particular importance to the household poultry were categorized and highly pathogenic avian influenza H5N1 was the most risky disease while people-related risk was the most important risk category. It was observed that basic biosecurity measures were applicable in the household poultry and it would be 8.45 times better to implement biosecurity than to do nothing against HPAI H5N1; 4.88 times better against Newcastle disease and 1.49 times better against coccidiosis. Sensitivity analyses proved that the household poultry project was robust and would withstand various uncertainties. An uptake pathway for basic biosecurity was suggested. The outcome of this work should support decisions to implement biosecurity at the household sector of poultry production.

Rapid antigen detection in the diagnosis of highly pathogenic avian influenza (H5N1) virus in Nigeria

Highly pathogenic avian influenza (AI) is an infectious disease of agroeconomic and public health importance. The outbreak that occurred in Nigeria (2006-2008) was devastating to the poultry industry and raised public health concerns. In the course of its control, rapid laboratory confirmation of suspected cases in poultry was essential for prompt mobilization of control logistics for depopulation and decontamination of affected premises. Commercial rapid test kit was evaluated in the diagnosis of highly pathogenic AI (HPAI) as a preliminary to virus isolation. Between 2006 and 2007, 382 cases were tested out of which 149 were positive by rapid antigen detection. Virus isolation yielded 171 positive cases. The relative diagnostic sensitivity of Anigen Rapid AIV Ag test was 84.3% (95% confidence interval [CI], 78.1-88.9%), whereas the relative diagnostic specificity was 97.7% (95% CI, 94.2-99.1%). Rapid antigen detection is a useful technique for prompt diagnosis of HPAI for early detection and containment.

Surveillance for African swine fever in Nigeria, 2006-2009

African swine fever (ASF) has had significant economic and social impact in Nigeria since 1997. However, there has been no effective national response to bring it under control. In this report, we confirm that ASF is still prevalent and widespread in Nigeria. Results from both serosurveillance and virological analyses indicated that ASF is present in most of the agro-ecological zones of the country. Nine per cent (9%) of serum samples and 48% of tissue samples were positive for ASF virus antibody and genome, respectively. Areas with high pig-related activities (marketing, consumption and farming) have higher prevalences compared with areas with less pig activities. Farm-gate buyers, marketing systems and transport of untested pigs within the country assist with the circulation of the virus. Only by putting in place a comprehensive routine surveillance and testing system, reorganizing the market and transportation systems for pigs, implementing on-farm bio-security protocols and considering the option of compensation will it be possible to achieve a significant reduction in ASF prevalence in Nigeria.

Avian influenza A(H5N1) in humans: lessons from Egypt

Highly pathogenic avian influenza A(H5N1) has ravaged the Egyptian poultry population. Ninety human cases, including 27 fatalities have been recorded by 30 December, 2009. However, epidemiological information on the infection in humans in Egypt is scarce. We analysed the first three years of highly pathogenic avian influenza A(H5N1) in Egypt between 20 March 2006 and 31 August 2009) and found that more cases occurred in females than males, especially in 2006 and 2007. Women in the age group 20-39 years had the greatest tendency to be infected. It took an average of one day and 18 hours to seek medical assistance in patients who recovered and of six days in fatal cases. Children sought treatment much earlier than adults. On average, a patient died 11 days after the onset of symptoms. Exposure to infected poultry remained the most important risk factor.

Avian influenza A(H5N1) in humans: lessons from Egypt

Highly pathogenic avian influenza A(H5N1) has ravaged the Egyptian poultry population. Ninety human cases, including 27 fatalities have been recorded by 30 December, 2009. However, epidemiological information on the infection in humans in Egypt is scarce. We analysed the first three years of highly pathogenic avian influenza A(H5N1) in Egypt between 20 March 2006 and 31 August 2009) and found that more cases occurred in females than males, especially in 2006 and 2007. Women in the age group 20-39 years had the greatest tendency to be infected. It took an average of one day and 18 hours to seek medical assistance in patients who recovered and of six days in fatal cases. Children sought treatment much earlier than adults. On average, a patient died 11 days after the onset of symptoms. Exposure to infected poultry remained the most important risk factor.

Serologic and virologic surveillance of avian influenza in Nigeria, 2006-7

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Serologic and virologic surveillance of avian influenza in Nigeria, 2006-7

Since January 2006, H5N1 avian influenza has affected Nigeria's poultry population causing enormous loss of resources. The current circulating virus is a potential candidate for pandemic influenza which may severely affect the human and animal population worldwide especially in the resource-poor countries. In this study, we report on our field and laboratory surveillance efforts in Nigeria. A total of 1,821 tissue samples, 8,638 tracheal swabs, 7,976 cloacal swabs and 7,328 avian sera were analysed over a period of two years, with 312 positive results [corrected] We recovered 299 isolates of highly pathogenic avian influenza virus H5N1 mainly from the diagnostic samples of poultry kept in backyard, small scale and free range farms. This finding emphasised the role played by these farming systems in the dissemination of avian influenza in Nigeria and highlights the need for a continued surveillance in humans since human-animal interaction is a key feature in Africa. Furthermore, there is a need for the strengthening of border controls. Since October 2007, there has been no reported and confirmed outbreak of avian influenza in Nigeria.

Control Versus No Control: Options for Avian Influenza H5N1 in Nigeria

In January 2006, an outbreak of a highly pathogenic avian influenza (HPAI) was recorded in Nigeria for the first time. This present work describes an estimation of possible costs associated with a vaccination-based control policy added to other measures to restrict HPAI H5N1 virus infections. The evaluations used epidemiological and production data, including budgets necessary for the vaccine acquisition, distribution and administration in arriving at the final costs. Using decision tree and cost benefit analysis the economical benefits for Nigeria and countries with similar veterinary infrastructures, biosecurity and farming systems are calculated. The result indicated that a halting in the continued spread of the virus through effective control measure will be 52 times better than taking no action. This should help policy makers in deciding in favour of vaccination combined with other tools as an effective means of controlling avian influenza H5N1. * Control of HPAI H5N1 will best be understood by policy makers in financial terms. * Effective control through vaccination of poultry is much cheaper and reduces the chances of human zoonoses. * Poultry vaccination combined with other control measures will be the most effective means of control in most developing economies.