From cow to consumer: using value chain approaches to evaluate infectious disease risk along dairy value chains serving urban consumers in Moshi Municipality, northern Tanzania

The global population is rapidly urbanising, with East Africa experiencing some of the fastest rates of urban growth. Urbanisation drives changes in diet, including increased consumption of animal source products (ASPs), and livestock value chains are becoming increasingly long and complex to meet these demands. This may place urban consumers at increased risk of food-borne infectious diseases. Evaluation of food-borne disease (FBD) risk to urban consumers in developing countries has been hampered by a lack of data on the composition of urban diets, and a lack of methodologies to systematically assess risk along food value chains which are typically informal, unregistered, and unregulated. This research used a value chain risk assessment approach (VCRA) to evaluate food-borne infectious disease risks along dairy value chains supplying Moshi Municipality, the regional capital of Kilimanjaro, Northern Tanzania. Our findings demonstrated that by far the most frequently consumed products were unpackaged milk and mtindi (fermented milk). While there was some role for urban livestock keepers in supplying these products to their communities directly, most of the milk and mtindi sold within Moshi originated with milk produced by smallholder farmers in rural areas surrounding the towns. Both the milk and mtindi value chains involved similar value chain nodes and actors, with a large degree of overlap between the formal and informal sectors and little to no formal education or training on milk handling and hygiene for chain participants. VCRA identified the bulking, wholesale and retail stages of the value chain as potential hotspots for introducing infectious disease risk. Consumers were well informed about many of the FBD risks posed by milk, and took active steps to mitigate these risks by boiling before consumption; however they perceived mtindi as posing a lower risk and were unable to mitigate risks with any preparatory step as mtindi is consumed as purchased. The highest risk to consumers was estimated to be posed by mtindi rather than milk, particularly mtindi made from leftover unsold milk, as this milk had a high risk of contamination. More studies are needed to investigate the infectious hazards present in both mtindi and other fermented milk products which are consumed widely across the region. The practice of valorising leftover ASPs as alternative products for human consumption may represent a particular source of FBD risk to urban consumers in developing countries

One health research in Northern Tanzania – challenges and progress

East Africa has one of the world’s fastest growing human populations—many of whom are dependent on livestock—as well as some of the world’s largest wildlife populations. Humans, livestock, and wildlife often interact closely, intimately linking human, animal, and environmental health. The concept of One Health captures this interconnectedness, including the social structures and beliefs driving interactions between species and their environments. East African policymakers and researchers are recognising and encouraging One Health research, with both groups increasingly playing a leading role in this subject area. One Health research requires interaction between scientists from different disciplines, such as the biological and social sciences and human and veterinary medicine. Different disciplines draw on norms, methodologies, and terminologies that have evolved within their respective institutions and that may be distinct from or in conflict with one another. These differences impact interdisciplinary research, both around theoretical and methodological approaches and during project operationalisation. We present experiential knowledge gained from numerous ongoing projects in northern Tanzania, including those dealing with bacterial zoonoses associated with febrile illness, foodborne disease, and anthrax. We use the examples to illustrate differences between and within social and biological sciences and between industrialised and traditional societies, for example, with regard to consenting procedures or the ethical treatment of animals. We describe challenges encountered in ethical approval processes, consenting procedures, and field and laboratory logistics and offer suggestions for improvement. While considerable investment of time in sensitisation, communication, and collaboration is needed to overcome interdisciplinary challenges inherent in One Health research, this can yield great rewards in paving the way for successful implementation of One Health projects. Furthermore, continued investment in African institutions and scientists will strengthen the role of East Africa as a world leader in One Health research

Zoonotic causes of febrile illness in malaria endemic countries:a systematic review

Fever is one of the most common reasons for seeking health care globally and most human pathogens are zoonotic. We conducted a systematic review to describe the occurrence and distribution of zoonotic causes of human febrile illness reported in malaria endemic countries. We included data from 53 (48·2%) of 110 malaria endemic countries and 244 articles that described diagnosis of 30 zoonoses in febrile people. The majority (17) of zoonoses were bacterial, with nine viruses, three protozoa, and one helminth also identified. Leptospira species and non-typhoidal salmonella serovars were the most frequently reported pathogens. Despite evidence of profound data gaps, this Review reveals widespread distribution of multiple zoonoses that cause febrile illness. Greater understanding of the epidemiology of zoonoses in different settings is needed to improve awareness about these pathogens and the management of febrile illness

An outbreak of scabies in multiple linked healthcare settings in the Netherlands

Item does not contain fulltextWe report a large scabies outbreak occurring in Tilburg, Netherlands, which affected several different healthcare settings that provide care to the elderly and the mentally disabled. The outbreak demonstrated how the complex system of care provision to vulnerable groups facilitated extensive scabies transmission among multiple linked healthcare settings and the community

Dynamic Transmission of Numerous Anaplasma phagocytophilum Genotypes among Lambs in an Infected Sheep Flock in an Area of Anaplasmosis Endemicity▿

The transmission dynamics of Anaplasma phagocytophilum strains circulating within juvenile members of a sheep flock grazing on an Ixodes ricinus-infested pasture in southern Norway were monitored. PCR-based detection of the bacterial p44 fragments in the blood of 16 lambs sampled weekly for 16 weeks following their release into pasture revealed rickettsemia in all animals, with an increasing proportion of infected animals as the survey progressed. Comparison of partial msp4 sequences obtained from infected blood samples revealed 24 distinct genotypes, some of which were repeatedly encountered, occurring in up to six sheep over a 14-week period, whereas others were observed only once. Individual sheep were infected by up to five distinct genotypes, with a specific genotype being encountered for between one and three consecutive weeks, and in some sheep, genotypes detected early in the study were also present in later samples. In general, detection of A. phagocytophilum by PCR correlated well with the observation of infected neutrophils in blood smears. Together these results reveal a previously unrecognized diversity of A. phagocytophilum strains simultaneously circulating within an infected population in an area of endemicity and are consistent with a remarkably dynamic transmission of strains among infected animals

Population seroprevalence study after a West Nile virus lineage 2 epidemic, Greece, 2010.

INTRODUCTION: During summer 2010, 262 human cases including 35 deaths from West Nile virus (WNV) infection were reported from Central Macedonia, Greece. Evidence from mosquitoes, birds and blood donors demonstrated that the epidemic was caused by WNV lineage 2, which until recently was considered of low virulence. We conducted a household seroprevalence study to estimate the spread of infection in the population during the epidemic, ascertain the relationship of infection to clinical disease, and identify risk factors for infection. METHODS: We used a two-stage cluster design to select a random sample of residents aged ≥18 years in the outbreak epicentre. We collected demographic, medical, and risk factor data using standard questionnaires and environmental checklists, and tested serum samples for presence of WNV IgG and IgM antibodies using ELISA. RESULTS: Overall, 723 individuals participated in the study, and 644 blood samples were available. Weighted seropositivity for IgG antibodies was 5.8% (95% CI: 3.8-8.6; n=41). We estimated that about 1 in 130 (1:141 to 1:124) infected individuals developed WNV neuroinvasive disease, and approximately 18% had clinical manifestations attributable to their infection. Risk factors for infection reflected high exposure to mosquitoes; rural residents were particularly at risk (prevalence ratio: 8.2, 95% CI: 1.1-58.7). DISCUSSION: This study adds to the evidence that WNV lineage 2 strains can cause significant illness, demonstrating ratios of infection to clinical disease similar to those found previously for WNV lineage 1

Population Seroprevalence Study after a West Nile Virus Lineage 2 Epidemic, Greece, 2010

Introduction: During summer 2010, 262 human cases including 35 deaths from West Nile virus (WNV) infection were reported from Central Macedonia, Greece. Evidence from mosquitoes, birds and blood donors demonstrated that the epidemic was caused by WNV lineage 2, which until recently was considered of low virulence. We conducted a household seroprevalence study to estimate the spread of infection in the population during the epidemic, ascertain the relationship of infection to clinical disease, and identify risk factors for infection. Methods: We used a two-stage cluster design to select a random sample of residents aged >= 18 years in the outbreak epicentre. We collected demographic, medical, and risk factor data using standard questionnaires and environmental checklists, and tested serum samples for presence of WNV IgG and IgM antibodies using ELISA. Results: Overall, 723 individuals participated in the study, and 644 blood samples were available. Weighted seropositivity for IgG antibodies was 5.8% (95% CI: 3.8-8.6; n=41). We estimated that about 1 in 130 (1: 141 to 1: 124) infected individuals developed WNV neuroinvasive disease, and approximately 18% had clinical manifestations attributable to their infection. Risk factors for infection reflected high exposure to mosquitoes; rural residents were particularly at risk (prevalence ratio: 8.2, 95% CI: 1.1-58.7). Discussion: This study adds to the evidence that WNV lineage 2 strains can cause significant illness, demonstrating ratios of infection to clinical disease similar to those found previously for WNV lineage 1

A Model for the Early Identification of Sources of Airborne Pathogens in an Outdoor Environment

<div><p>Background</p><p>Source identification in areas with outbreaks of airborne pathogens is often time-consuming and expensive. We developed a model to identify the most likely location of sources of airborne pathogens.</p><p>Methods</p><p>As a case study, we retrospectively analyzed three Q fever outbreaks in the Netherlands in 2009, each with suspected exposure from a single large dairy goat farm. Model input consisted only of case residential addresses, day of first clinical symptoms, and human population density data. We defined a spatial grid and fitted an exponentially declining function to the incidence-distance data of each grid point. For any grid point with a fit significant at the 95% confidence level, we calculated a measure of risk. For validation, we used results from abortion notifications, voluntary (2008) and mandatory (2009) bulk tank milk sampling at large (i.e. >50 goats and/or sheep) dairy farms, and non-systematic vaginal swab sampling at large and small dairy and non-dairy goat/sheep farms. In addition, we performed a two-source simulation study.</p><p>Results</p><p>Hotspots – areas most likely to contain the actual source – were identified at early outbreak stages, based on the earliest 2–10% of the case notifications. Distances between the hotspots and suspected goat farms varied from 300–1500 m. In regional likelihood rankings including all large dairy farms, the suspected goat farms consistently ranked first. The two-source simulation study showed that detection of sources is most clear if the distance between the sources is either relatively small or relatively large.</p><p>Conclusions</p><p>Our model identifies the most likely location of sources in an airborne pathogen outbreak area, even at early stages. It can help to reduce the number of potential sources to be investigated by microbial testing and to allow rapid implementation of interventions to limit the number of human infections and to reduce the risk of source-to-source transmission.</p></div

Additional file 1: Table S1. of Integrating interdisciplinary methodologies for One Health: goat farm re-implicated as the probable source of an urban Q fever outbreak, the Netherlands, 2009

Attack rates and relative risks per potential source farm. Number of cases, number of total inhabitants, attack rates (AR) per 100,000 inhabitants, and relative risks (RR) per concentric 1 km ring around each potential source farm A – Q. (XLS 29 kb

Additional file 2: Figure S1. of Integrating interdisciplinary methodologies for One Health: goat farm re-implicated as the probable source of an urban Q fever outbreak, the Netherlands, 2009

Results of spatio-temporal analysis using an alternative emission profile. As for Fig. 5, but for emission profile lNormEpi. (PDF 564 kb