Where literature is scarce: observations and lessons learnt from four systematic reviews of zoonoses in African countries

Determinants of viral haemorrhagic fever risk in Africa's tropical moist forests: A scoping review of spatial, socio-economic, and environmental factors

BACKGROUND

Viral haemorrhagic fevers (VHFs) are identified by international health authorities as priorities for research and development, as they pose a threat to global health and economy. VHFs are zoonotic diseases whose acute forms in humans present a haemorrhagic syndrome and shock, with mortality rates of up to 90%. This work aims at synthetizing existing knowledge on spatial and spatially aggregable determinants that support the emergence and maintenance of VHFs in African countries covered by tropical moist forest, to better identify and map areas at risk.

METHODOLOGY/PRINCIPAL FINDINGS

Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA-ScR) guidelines, extension for scoping reviews, we searched the PubMed, Embase, CAB Abstracts, and Scopus databases. English and French peer-reviewed documents were retrieved using Boolean logic and keyword search terms. The analysis of 79 articles published between 1993 and 2023 offers a comprehensive overview of the complex interactions among abiotic, biotic, demographic, socio-economic, cultural, and political risk factors in driving the emergence and maintenance of VHFs in African countries covered by tropical moist forests. Human-to-human transmission is mainly driven by socio-economic, political, and demographic factors, whereas zoonotic spillover is determined by almost all groups of factors, especially those of an anthropogenic nature.

CONCLUSIONS/SIGNIFICANCE

Many questions remain unanswered regarding the epidemiology of VHFs in tropical forests. By elucidating spatially relevant determinants which have already been studied, this review seeks to advance VHFs hotspot predictions, risk mapping for disease surveillance and control systems improvement.

Countering Zoonotic Diseases: Current Scenario and Advances in Diagnostics, Monitoring, Prophylaxis and Therapeutic Strategies

Human life and health have interacted reciprocally with the surrounding environment and animal fauna for ages. This relationship is evident in developing nations, where human life depends more on the animal population for food, transportation, clothing, draft power, and fuel sources, among others. This inseparable link is a potent source of public health issues, especially in outbreaks of zoonotic diseases transmitted from animals to humans. Zoonotic diseases are referred to as diseases that are naturally transmitted between vertebrate animals and humans. Among the globally emerging diseases in the last decade, 75% are of animal origin, most of which are life-threatening. Since most of them are caused by potent new pathogens capable of long-distance transmission, the impact is widespread and has serious public health and economic consequences. Various other factors also contribute to the transmission, spread, and outbreak of zoonotic diseases, among which industrialization-led globalization followed by ecological disruption and climate change play a critical role. In this regard, all the possible strategies, including advances in rapid and confirmatory disease diagnosis and surveillance/monitoring, immunization/vaccination, therapeutic approaches, appropriate prevention and control measures to be adapted, and awareness programs, need to be adopted collaboratively among different health sectors in medical, veterinary, and concerned departments to implement the necessary interventions for the effective restriction, minimization, and timely control of zoonotic threats. The present review focuses on the current scenario of zoonotic diseases and their counteracting approaches to safeguard their health impact on humans.

Foodborne Microbiological Hazards in Ghana: A Scoping Review

Background

Foodborne diseases pose a significant public health threat, particularly in regions with poor sanitation and food handling practices. These diseases, mainly caused by microbiological hazards like bacteria, fungi, and parasites, affect millions globally. Despite the global burden, the true extent of these hazards remains underestimated, especially in low- and middle-income countries like Ghana. This study aimed to map the available literature on foodborne microbiological hazards in Ghana, providing an overview of the evidence and identifying areas where further research is needed.

Method

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis Extension for Scoping Reviews. A detailed search was done in PubMed, Scopus, Web of Science, and Google Scholar, and articles were exported to Rayyan for screening. A three-phase screening process was used to identify relevant articles. Data from the included articles were extracted and analysed, with specific information related to food type, specific hazards, sample population, and hazard groups summarised using proportions and tables.

Results

This review included 72 studies which were published between 2001 and 2023. Eighty-five percent of these studies (85%) reported on bacterial hazards, while 19%, 11%, and 6% reported on fungi, parasites, and mycotoxins, respectively. The most reported bacterial, fungal, and parasitic hazards were Escherichia coli, Aspergillus spp. and Trichuris trichiura, respectively. Aflatoxins were reported in maize, groundnut, and spices, with prevalence ranging from 61% to 100% and at levels exceeding standards set by Ghana Standards Authority and European Food Safety Authority.

Conclusion

This review highlighted the spectrum of microbiological hazards in foods in Ghana. The hazards identified pose significant public health risks, particularly among vulnerable populations. It is crucial that stricter enforcement of food safety laws and improved food handling practices are implemented in the country, particularly in the informal food sector, to protect consumers.

The socioeconomic impact of equine epizootic lymphangitis in working equids in low and middle-income countries: A scoping review

Equine epizootic lymphangitis (EEL) is a very infectious and contagious fungal disease that, with its ocular, respiratory and skin forms, causes severe effects on the health and welfare of working equids. Treatment is expensive and rarely available in low and middle-income countries (LMICs). Epidemiological data is lacking in most countries where the disease is known to exist. The purpose of this scoping review is to identify the current knowledge on the socioeconomic impact of EEL in working equids in LMICs, to highlight knowledge gaps and provide recommendations for future research. Seven eligible papers were obtained from the search of four databases and backward citation searching. The review showed that the available research on this subject is very scarce and restricted to Ethiopia. From the results it emerged that EEL causes detrimental socioeconomic effects on working equids' owners, compromising their health and livelihood. Its economic consequences were attributed to the reduced working capacity and loss of sick animals. Among the social impacts, authors highlighted the stigma around sick equids and their owners. Further studies on the socioeconomic impact of EEL conducted in endemic areas are highly required. The integration of epidemiological data with socioeconomic impact studies from LMICs may promote funding allocation for the development of cost-effective treatments and vaccines and for implementing disease prevention and control programmes. Future research would gain from applying the One Health approach to better examine the multiplicity of the disease socioeconomic effects, therefore increasing the potential of research to orientate policy.

The Socioeconomic Impact of Diseases of Working Equids in Low and Middle-Income Countries: A Critical Review

Working equids provide a crucial contribution to the livelihoods and food security of communities in low- and middle-income countries (LMICs). Nevertheless, they are a neglected category within animal health policies and interventions of governmental and non-governmental institutions. This critical review aims to assess the socioeconomic impact of diseases of working equids in LMICs. By highlighting the implications of diseases on working equid welfare, human wellbeing and livelihoods, this review seeks to sensitise policymakers within governments and international organisations to develop policies and interventions aimed at protecting the health of working equids and, consequently, the health and livelihoods of their dependent communities. Twenty relevant publications were identified through the search of five databases (CAB Abstracts, Web of Science Core Collection, BIOSIS, EMBASE and Scopus), backward citation searching and screening of indexes of proceedings and Special Issues retrieved from the database search. The review findings show that diseases of working equids have detrimental socioeconomic effects. However, this subject is under-researched and restricted to few diseases and geographical settings. Considering the complexity of the issue, this review demonstrates that the 'One Health' approach represents an opportunity to clarify the link between equid health, human wellbeing and livelihoods, facilitating the translation of research into policy.

Foodborne disease hazards and burden in Ethiopia: A systematic literature review, 1990–2019

Background

Foodborne disease (FBD) affects millions of people each year, posing a health burden similar to malaria, tuberculosis or HIV. A recent World Bank study estimated the productivity losses alone attributed to unsafe food within Africa at $20 billion in 2016, and the cost of treating these illnesses at an additional $3.5 billion. Ethiopia faces multiple food safety challenges due to lack of infrastructure and basic pre-requisites for food safety such as clean water and environment, washing facilities, compounded by limited implementation of food safety regulations, and a lack of incentives for producers to improve food safety. A consolidation of our understanding and evidence of the source, nature and scale of FBD in Ethiopia is needed to inform policy and future research. We performed a Systematic Literature Review (SLR) of publications on FBD occurrence in Ethiopia including hazard presence and impact.

Method

The SLR followed Cochrane and PRISMA guidelines. We searched PubMed and CAB-Direct for relevant publications between 1990 and 2019 (inclusive). Observational studies and reviews were included. Two reviewers screened titles and abstracts, and retained publications were reviewed in full for quality and data extraction.

Result

In total 128 articles met the inclusion criteria. Most articles focused on the identification of biological hazards in food. High levels of microbial contamination in different food value chains were often found in the small, ad hoc, observational studies that dominated the literature. Raw milk (22/128, 17.0%) and raw beef (21/128, 16.4%) were the most studied food products. Foodborne (FB) parasites were often found at higher rates in food than bacterial and viral pathogens, possibly due to differences in ease of identification. High levels of bacterial contamination on the hands of food handlers were widely reported. There were no reports on the incidence of human FBDs or resulting health and economic impacts.

Conclusion

Our findings reflect existing concerns around food safety in Ethiopia. A lack of substantial, coordinated studies with robust methodologies means fundamental gaps remain in our knowledge of FBD in Ethiopia, particularly regarding FBD burden and impact. Greater investment in food safety is needed, with enhanced and coordinated research and interventions.

Systematic map of the most recent evidence (2010-2019) on ruminant production-limiting disease prevalence and associated mortality in Ethiopia

Background

Ethiopia's livestock sector supports the livelihoods of millions of smallholder farmers. However, despite the improvements of recent years, livestock productivity remains low due to critical constraints, including infectious diseases. The aim of this study was to collate and synthesize the published evidence on ruminant disease frequency and disease-associated mortality in Ethiopia, by identifying knowledge gaps and clusters in the literature to provide the basis for a decision-making tool.

Methods

Searches on both bibliographic and organization databases were conducted in English and were restricted to the period 2010-2019. Search results were screened for relevance at title, abstract and full text level.

Results

There were 716 articles identified relevant to the research question. The systematic map revealed an increased publication output from 2012-2017, compared to 2010-2011 and 2018-2019. Most studies were conducted in Oromia, Amhara and SNNPR. A substantial body of evidence was found for trypanosomosis, ectoparasite infestation, fasciolosis, nematodiasis, echinococcosis, and brucellosis.

Conclusion

This study suggests that despite the high output of epidemiological publications, further understanding of a considerable number of diseases is required and where evidence is abundant, synthesis of information should be carried out in order to better inform decisions on disease control priorities in the livestock sector.

The Global Contributions of Working Equids to Sustainable Agriculture and Livelihoods in Agenda 2030

Small farmers produce most food in low- and middle-income countries and most small farmers rely on directly or indirectly working equids (WE). The lack of methods and metrics for assessing the role of WE hampers realisation of WE contributions. Based on literature review and a survey of WE welfare experts, we propose a framework for optimising WE potential based on two axes of sustainable development goals (SDGs) and value chains. WE contribute especially to earning and sparing income (largely in food production) (SDG 1), but also have roles in accessing health and hygiene services and products (SDG 3 and 5), providing edible products (SDG 2), and benefiting women (SDG 6), with lesser contributions to other SDGs, notably climate action (SDG 13). Experts identified barriers to appropriate appreciation of WE contributions, in order to target actions to overcome them. They found WE are neglected because they belong to farmers who are themselves neglected; because information on WE is inadequate; and, because the unique nature and roles of WE means systems, policies, investors, markets and service providers struggle to cater for them. Harnessing WE to optimally contribute to sustainable development will require generating better evidence on their contributions to SDGs, ensuring better integration into ongoing efforts to attain SDGs, and building the WE capacity among development actors.

A systematic review and meta-analysis of the aetiological agents of non-malarial febrile illnesses in Africa

Background

The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades. Therefore, we undertook a systematic literature review and meta-analysis of causative agents of non-malarial fevers on the African continent.

Methodology

We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of Science databases to identify aetiologic agents that had been reported and to determine summary estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever patients.

Findings

A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible. A wide array of aetiologic agents were described with considerable regional differences among the leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest proportion. The summary estimates from the meta-analysis were low for most of the agents. This may have resulted from a true low prevalence of the agents, the failure to test for many agents or the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and population variables showed that diagnostic methods determined the PMr estimates of typhoidal Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of Haemophilus spp. infections.

Conclusion

The small number of epidemiological studies and the variety of NMFI agents on the African continent emphasizes the need for harmonized studies with larger sample sizes. In particular, diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public health strategies.

Previous systematic reviews have highlighted the research priorities of causative agents for non-malarial febrile illnesses by counting the number of publications attributed to an agent. However, proportional morbidity rates are calculated by dividing the number of cases with a specific disease (numerator) by the total number of diagnosed fever cases (denominator) and are better indicators of the relative importance of aetiological agents in a population. Therefore, we present the leading causes of non-malarial febrile illnesses in African patients in both healthcare and community settings. Preference is given to HIV-negative patients when data could be found. We also determined summary estimates of Brucella spp., Chikungunya virus, Dengue virus, Haemophilus spp., Klebsiella spp., Leptospira spp., non-typhoidal Salmonella spp., typhoidal Salmonella spp., Staphylococcus spp., and Streptococcus spp.

The wide array of aetiological agents causing febrile illnesses on the African continent does not only complicate malaria control programs but may also hamper response to epidemic and pandemic illnesses such as Ebola and COVID-19. The harmonisation of diagnostics and study designs will reduce between-study differences, which may result in better estimates of disease burden on the continent and in the different African regions. This information is important for Pan-African surveillance and control efforts.

One hundred years of zoonoses research in the Horn of Africa: A scoping review

BACKGROUND

One Health is particularly relevant to the Horn of Africa where many people's livelihoods are highly dependent on livestock and their shared environment. In this context, zoonoses may have a dramatic impact on both human and animal health, but also on country economies. This scoping review aimed to characterise and evaluate the nature of zoonotic disease research in the Horn region. Specifically, it addressed the following questions: (i) what specific zoonotic diseases have been prioritised for research, (ii) what data have been reported (human, animal or environment), (iii) what methods have been applied, and (iv) who has been doing the research?

METHODOLOGY/PRINCIPAL FINDINGS

We used keyword combinations to search online databases for peer-reviewed papers and theses. Screening and data extraction (disease, country, domain and method) was performed using DistillerSR. A total of 2055 studies focusing on seven countries and over 60 zoonoses were included. Brucellosis attracted the highest attention in terms of research while anthrax, Q fever and leptospirosis have been comparatively under-studied. Research efforts did not always align with zoonoses priorities identified at national levels. Despite zoonoses being a clear target for 'One Health' research, a very limited proportion of studies report data on the three domains of human, animal and environment. Descriptive and observational epidemiological studies were dominant and only a low proportion of publications were multidisciplinary. Finally, we found that a minority of international collaborations were between Global South countries with a high proportion of authors having affiliations from outside the Horn of Africa.

CONCLUSIONS/SIGNIFICANCE

There is a growing interest in zoonoses research in the Horn of Africa. Recommendations arising from this scoping review include: (i) ensuring zoonoses research aligns with national and global research agendas; (ii) encouraging researchers to adopt a holistic, transdisciplinary One Health approach following high quality reporting standards (COHERE, PRISMA, etc.); and (iii) empowering local researchers supported by regional and international partnerships to engage in zoonoses research.

Evaluating farm-level livestock interventions in low-income countries: a scoping review of what works, how, and why

Livestock interventions can improve nutrition, health, and economic well-being of communities. The objectives of this review were to identify and characterize livestock interventions in developing countries and to assess their effectiveness in achieving development outcomes. A scoping review, guided by a search strategy, was conducted. Papers needed to be written in English, published in peer-reviewed journals, and describe interventions in animal health and production. Out of 2739 publications systematically screened at the title, abstract, and full publication levels, 70 met our inclusion criteria and were considered in the study. Eight relatively high-quality papers were identified and added, resulting in 78 reviewed publications. Only 15 studies used randomized controlled trial designs making it possible to confidently link interventions with the resulting outcomes. Eight studies had human nutrition or health as outcomes, 11 focused on disease control, and four were on livestock production. Eight interventions were considered successful, but only four were scalable. We found good evidence that livestock-transfer programs, leveraging livestock products for nutrition, and helping farmers manage priority diseases, can improve human well-being. Our report highlights challenges in garnering evidence for livestock interventions in developing countries and provides suggestions on how to improve the quantity and quality of future evaluations.

Zoonotic Pathogens of Dromedary Camels in Kenya: A Systematised Review

Kenya is home to Africa’s third largest population of dromedary camels, and production at commercial and local levels are increasingly important. In pastoral and nomadic communities in the arid and semi-arid lands (ASALs), camels play a vital role in food security, while commercial milk production and formalized export markets are rapidly emerging as camel populations expand into non-traditional areas. Until recently, little focus was placed on camels as hosts of zoonotic disease, but the emergence of Middle Eastern respiratory coronavirus (MERS-CoV) in 2012, and the discovery of exposure to the virus in Kenyan camels, highlighted the need for further understanding of this area. This systematised review utilised a robust search strategy to assess the occurrence of camel-associated zoonoses in Kenya and to evaluate the quality of the published literature. Seventy-four studies were identified, covering sixteen pathogens, with an increasing number of good quality studies in recent years. Despite this, the area remains under-researched and there is a lack of robust, high-quality research. Trypanosome spp., Echinococcus granulosus and Brucella spp. appeared most frequently in the literature. Pathogens with the highest reported prevalence were MERS-CoV (0–100%), Echinococcus granulosa (7–60%) and Rift Valley fever virus (7–57%). Exposure to Brucella spp., Coxiella burnetii and Crimean-Congo haemorrhagic fever virus showed higher levels in camel or camel-associated vectors than other livestock species, although brucellosis was the only disease for which there was robust evidence linking camel and human exposure. Zoonotic agents with less severe human health outcomes, such as Dermatophilosus congolensis and contagious ecthyma, were also represented in the literature. This review provides an important summary of the scope and quality of current knowledge. It demonstrates that further research, and improved adherence to robust study design and reporting are essential if the zoonotic risk from camels in Kenya, and elsewhere, is to be better understood.

Development of a systematic mapping review protocol for the most recent evidence on ruminant infectious disease frequency and disease-associated mortality: Ethiopia as a case study

Almost 19% of the GDP of Ethiopia results from livestock production. Ruminants, in particular, form the majority of the national herd and are a critical source of income for smallholder farmers. Infectious diseases have been identified as a major cause of reduced livestock productivity in low- and middle-income countries (LMICs); therefore, a sound and comprehensive understanding of the relevant evidence would be beneficial in order to enable decision making on disease control policies. However, livestock disease data from sub-Saharan Africa is variable and disparate, which poses a challenge for evidence synthesis. This paper describes a protocol for a systematic mapping review of the recent available evidence on ruminant disease prevalence and associated mortality in Ethiopia. Literature sources will be identified using database search strategies. The titles, abstracts and, subsequently, full texts will be screened for inclusion based on predefined eligibility criteria. Specific data will be extracted and a preliminary qualitative assessment of the evidence will be performed using predefined indicators. The planned systematic map will be the first to provide a large-scale overview of the available ruminant disease evidence in Ethiopia; the final output will be an interactive dashboard tool to inform critical stakeholders in policy and research.

Zoonotic pathogens in urban animals: Enough research to protect the health of the urban population?

With more than half of the global population living in cities, the urban areas are also teeming with animals, including peridomestic wildlife, pets, and livestock. Urban animals may carry zoonotic pathogens, and crowded conditions in cities can increase the risk for the human population. We used a systematic approach to screen two publication databases as well as gray literature, and quantified the studies conducted on zoonoses in urban animals with respect to the geographic distribution, the host animal and pathogens. Out of 876 references found, 93 were included into final data extraction. Few studies were from the rapidly expanding cities in low- and middle-income countries where urban livestock-keeping is far more prominent than in high-income countries. Most studies were performed in peridomestic wildlife and pets, less in livestock. The most common category of pathogens studied were gastrointestinal parasites followed by gastrointestinal bacteria, whereas studies on some other zoonoses internationally recognized as critical for public health were few or absent. In conclusion, to mitigate the risks of emergence of zoonoses from urban animals this review highlights the research gaps on zoonoses, particularly in livestock in rapidly growing tropical cities and a more comprehensive inclusion of pathogens prioritized by WHO and OIE.

Students' and supervisors' knowledge and attitudes regarding plagiarism and referencing

Background

Referencing is an integral part of scientific writing and professional research conduct that requires appropriate acknowledgement of others’ work and avoidance of plagiarism. University students should understand and apply this as part of their academic development, but for this, it is essential that supervisors also display proper research integrity and support.

Methods

This study used an online educative questionnaire to understand the knowledge and attitudes of students and supervisors at two institutes in Europe and Africa. The results were then used to create discussion around education of students and faculty in workshops and lectures.

Results

Overall, 138 students and 14 supervisors participated: most were Swedish (89) and Kenyan (11). Overall, 98% had heard about plagiarism, and 35% believed it was common. Only 45% had heard about self-plagiarism, and when explained what it was, 44.5% considered it morally wrong. Europeans and North Americans had more knowledge than other nationalities. Most (85%) had received some training on referencing, but there was little consensus about principles, with more than 30% considering it acceptable to cite a reference in a paper they had not read. Discussing these results and the questions in workshops was helpful; it was also clear that there was no consensus among supervisors on what constituted correct behavior.

Conclusions

This survey shows a need for greater consensus on appropriate referencing, and that there is need for more discussions and training on the topic for both students and faculty.

Electronic supplementary material

The online version of this article (10.1186/s41073-018-0054-2) contains supplementary material, which is available to authorized users.

Occupational Practices and Hazards of Rural Livestock Keepers in Uganda: A Cross-Sectional Study

Objective:

In Uganda, 70% of rural poor rely on livestock for subsistence, to meet social obligations, and to insure against disaster. Livestock farming in Africa is in a state of transition from traditional management systems toward intensified modern systems, calling into question the future of traditional systems. To inform this debate, we conducted a survey in Moyo District, Uganda, to describe occupational practices and hazards of agropastoralist livestock keepers.

Methods:

Household surveys were administered to heads of household (N=49) from July to September 2016. Cross-sectional data were used to generate descriptive statistics for livestock-associated practices and exposures. Logistic regression was used to estimate odds ratios and Wald-type 95% confidence intervals for risk factors for injury, defined as any animal-related injury in the household in the past year. Risk factors studied were total number of male animals; number of male cattle, sheep/goats, and pigs; proportion male by herd size; herd size; and castration practices.

Results:

Adult men perform most livestock-associated tasks, while women, girls, and boys prepare meat, milk cattle, care for poultry, and dispose of waste. While 31 (63%) of households use professional veterinary services and most (n=28, 57.2%) are familiar with zoonoses, 25 (53.2%) do not believe sick animals may look healthy. Over 85.0% (n=41) of respondents routinely wash their hands, while only 31 (64.6%) use soap. Twenty-eight (57.0%) reported using personal protective equipment, while none used gloves or face protection. Most respondents had contact with animal waste “often”, and had contact with urine and blood “sometimes”. Six (12%) reported a needlestick injury while treating an animal, and 22 (45%) reported at least 1 injury from an animal. No significant association was found between the risk factors studied and animal injury, after adjustment for confounders.

Conclusions:

Occupational risks for female and young agropastoralists are distinct from those of men. Contact with potentially infectious material is common and current practices – handwashing without soap and low glove use – do little to prevent zoonotic transmission. While agropastoralists are familiar with zoonoses, subclinical infections may be missed. While no significant risk factors were identified for animal injury, both animal and needlestick injuries are common. As livestock agriculture intensifies, these hazards will become more pronounced; drivers of risk behavior and animal injury must be identified to inform interventions to improve the occupational health of rural livestock keepers in Uganda.

First Report of the Occurrence of Trichinella-Specific Antibodies in Domestic Pigs in Central and Eastern Uganda

Previous research on trichinellosis in Africa focused on isolating Trichinella from wildlife while the role of domestic pigs has remained highly under-researched. Pig keeping in Uganda is historically recent, and evidence on zoonotic pig diseases, including infection with Trichinella species, is scarce. A cross-sectional survey on Trichinella seroprevalence in pigs was conducted in three districts in Central and Eastern Uganda from April 2013 to January 2015. Serum from a random sample of 1125 pigs from 22 villages in Eastern and Central Uganda was examined to detect immunoglobulin G (IgG) against any Trichinella spp. using a commercially available ELISA based on excretory-secretory antigen. ELISA positive samples were confirmed using Western Blot based on somatic antigen of Trichinella spiralis as recommended in previous validation studies. Diaphragm pillar muscle samples (at least 5 g each) of 499 pigs from areas with high ELISA positivity were examined using the artificial digestion method. Overall, 78 of all 1125 animals (6.9%, 95% CI: 5.6-8.6%) tested positive for antibodies against Trichinella spp. in the ELISA at significantly higher levels in Kamuli district compared to Masaka and Mukono districts. Thirty-one percent of the ELISA positive samples were confirmed IgG positive by the Western Blot leading to an overall seroprevalence of 2.1% (95% CI: 1.4-3.2%). The large proportion of ELISA positive samples that could not be confirmed using Western blot may be the result of cross-reactivity with other gastrointestinal helminth infections or unknown host-specific immune response mechanisms in local pig breeds in Uganda. Attempts to isolate muscle larvae for species determination using the artificial digestion method were unsuccessful. Due to the large number of muscle samples examined we are confident that even if pigs are infected, the larval burden in pork is too low to pose a major risk to consumers of developing trichinellosis. This was the first large systematic field investigation of Trichinella infection in domestic pigs in Uganda and its results imply that further studies are needed to identify the Trichinella species involved, and to identify potential sources of infection for humans.

Prevalence of tuberculosis, brucellosis and trypanosomiasis in cattle in Tanzania: a systematic review and meta-analysis

A meta-analysis was performed to derive prevalence estimates for Brucella spp., Mycobacterium spp. and Trypanosoma spp. in cattle in Tanzania using data derived from a systematic review of zoonotic hazards in cattle production systems. Articles published before 2012 reporting prevalence and considered at least moderate in quality were included in the analysis. Results showed high heterogeneity between studies, with wide ranges in the reported prevalence: Brucella (0.3–60.8%), Mycobacterium (0.1–13.2%) and Trypanosoma (0.82–33.3%). Overall meta-analytic mean prevalence estimates were 8.2% (95% CI 6.5–10.2), 1.28% (95% CI 0.35–4.58) and 10.3% (95% CI 6.20–16.70) respectively, for Brucella spp., Mycobacterium spp. and Trypanosoma spp. Time and region were predictors of variability of Brucella spp. prevalence, while diagnostic test was a strong predictor of Mycobacterium spp. prevalence, with higher prevalence estimates given by skin tests compared with post-mortem inspection. None of the studied factors were associated with prevalence of Trypanosoma spp. The small sample sizes, range of study locations, study designs and diagnostics used, contributed to high variability among prevalence estimates. Larger and more robust prevalence studies are needed to adequately support risk assessment and management of animal and public health threats.