Are we prepared for emerging and re-emerging diseases? Experience and lessons from epidemics occurred in Tanzania during the last five decades

This paper reviews preparedness for containing and controlling emerging and re-emerging diseases drawing lessons from disease events that occurred in animal and human populations in the last five decades (1961-2011). A comprehensive analysis based on retrieval and analysis of grey and published literature as well as reported cases was carried out to document type and trend of occurrence of emerging and re-emerging infectious diseases in different parts of Tanzania. Overall, the majority of diseases reported in the country were viral in nature followed by bacterial diseases. The trend for the occurrence shows a number of new emerging diseases as well as re-occurrence of old diseases in both animal (domestic and wild) and human populations. In humans, the major disease epidemics reported in the last five decades include cholera, influenza A H1N1, plague and rubella. In animals, the major epidemic diseases reported were Contagious Bovine Pleuropneumonia, Contagious Caprine Pleuropneumonia, Peste des petits ruminants and Giraffe Ear and Skin Diseases. Some epidemics have been reported in both human and animal populations including Rift Valley fever and anthrax.  The emergence of the ‘fit-for purpose’ approaches and technologies such as the discipline of One Health, use of participatory epidemiology and disease surveillance and mobile technologies offers opportunity for optimal use of limited resources to improve early detection, diagnosis and response to disease events and consequently reduced impact of such diseases in animal and human populations

Emerging viral infectious disease threat: Why Tanzania is not in a safe zone

Emerging diseases are global threat towards human existence. Every country is exposed to potentially emergence of infectious diseases. Several factor such as changes in ecology, climate and human demographics play different roles in a complex mechanism contributing to the occurrence of infectious diseases. Important aspects towards control in case of outbreaks are surveillance, preparedness and early response. Tanzania should therefore take opportunity of the calm situation currently present, to prepare. Except for HIV/AIDS, Tanzania has not experienced a major public health threat. However, the question is, is the country safe from emerging and re-emerging infectious diseases? In this article we try to explore the danger of emerging infectious disease (EID) epidemics in Tanzania and the risks attached if an outbreak is to occur. The aim is to formulate recommendations to the government, responsible authorities and general population of what can be done to improve the level of EID preparedness in the country. In conclusion, it is important to strengthen the capacity of community and healthcare staffs on how to respond to potential infectious disease outbreaks. Community-based surveillance systems should be incorporated into the national systems for early detection of public health events. It is also critical to enhance one health approach to increase cross-sectoral information sharing, surveillance and interventional strategies as regards to preparedness and response to disease outbreaks

Measuring, monitoring and improving mass dog vaccination programmes to control and eliminate rabies

Rabies is an acute viral infection which causes horrifying neurological symptoms that inevitably result in death. Every year at least 59,000 people are estimated to die from rabies and more than 10 million are treated with post-exposure prophylaxis (PEP). Over 90% of human rabies deaths occur in Asia and Africa following bites from domestic dogs. Although human rabies deaths are 100% preventable through the delivery of prompt PEP to bite victims following a bite, PEP is not accessible to many poor rural victims, most of whom subsist on less than US$1.25/day. Empirical and theoretical evidence shows that mass dog vaccination that reaches 70% of susceptible dog population can interrupt the transmission cycle. Rabies has been eliminated from industrialized countries through mass dog vaccination, and the continent-wide elimination of canine rabies from the Americas is now within reach. In contrast, no effective large-scale control of dog rabies has been achieved in Africa and information is still needed to optimise and sustain dog vaccination programmes. The aim of this thesis was to evaluate the rabies control programme in Tanzania. This thesis is presented as a series of three standalone chapters (Chapters 2-4) that are introduced and then summarised by a general introduction (Chapter 1) and a general discussion (Chapter 5) respectively. Achieving high coverage is the most important aim of any vaccination programme; however, assessing the vaccination coverage achieved is often neglected in rabies endemic countries. In Chapter 2, I compare three methods of measuring vaccination coverage (post-vaccination transects, school-based surveys, and household surveys) across 28 districts in different settings in southeast Tanzania and Pemba island in order to determine which is most precise method. These approaches were explored in detail in a single district in northwest Tanzania (Serengeti), where their performance in producing precise estimates of coverage was compared with a complete dog population census that also recorded dog vaccination status. Our analysis found that transect studies (counting vaccinated and unvaccinated dogs) immediately after the campaign is cheap, quick, and provides precise estimates. Therefore, transects were considered more appropriate for routine monitoring of mass vaccination campaigns than household or school-based surveys. In Chapter 3, I used data from Chapter 2 together with human population census data from Tanzanian Bureau of Statistics to develop a model for estimation of the size of dog populations in Tanzania. Knowledge of the size of the dog population is necessary to adequately plan and achieve the target of vaccinating 70% of susceptible dogs. I demonstrate that estimating dog population size using transect data gave more precise results than either household or school-based surveys. Therefore, transect data were used to develop a predictive model for estimating dog populations in districts lacking transect data. Using this model, I predict a dog population of 2.32 (95% CI 1.57,3.12) million in Tanzania and an average human to dog ratio of 20.7:1. In Chapter 4, I evaluate the implementation and performance of large-scale dog vaccination campaigns against rabies in Tanzania. For an effective rabies control and elimination, it is necessary to conduct vaccination campaigns in every village/street (completeness), achieve coverage of 70% (coverage) and return for dog vaccination within one year (timeliness). Therefore, in this Chapter 4, I assessed vaccination campaigns in terms of completeness, coverage and timeliness; I also investigated factors associated with and potentially causing success or failure of mass dog vaccinations, in terms of completeness and coverage. Overall, this study shows that Tanzania experienced notable challenges in the delivery of mass dog vaccinations. For example, although vaccination completeness improved over time, until the last two rounds of vaccinations, only 25% of districts had 100% campaigns completeness. Additionally, very few districts (27-36% of the study districts) achieved the recommended vaccination coverage of 70% between third and fifth round of vaccinations. Vaccination interval was planned to be annually but vaccinations delayed to more than two years, as a result, vaccinations were conducted in pulsed approach (not annually)

Brucellosis in northern Tanzania: Investigating the epidemiology of human infection and evaluating diagnostic test performance in animal hosts

Brucellosis is a widespread neglected zoonotic disease. It can cause severe and prolonged illness in people, as well as impacting on animal health and productivity. Brucellosis is endemic in much of sub-Saharan Africa (SSA). The global burden of brucellosis is suspected to be highest in SSA, where there are many livestock-keeping communities. Cattle, sheep and goats are common maintenance hosts of zoonotic Brucella spp. Pastoralist communities in frequent contact with these livestock species are at increased risk of infection. This study was performed to improve our understanding of the epidemiology of brucellosis in Tanzania through: a risk factor analysis for human acute brucellosis cases; trialling an active surveillance approach to identify additional cases through household screening in a high-risk population; and latent class analyses to evaluate diagnostic test performance in different animal hosts. In Chapter 2, questionnaire data were collected from febrile patients attending a rural hospital in the Ngorongoro Conservation Area (NCA), Tanzania. Risk factors associated with acute brucellosis were: having herded cattle, sheep and/or goats in the past 12 months; and decreasing age in years. In Chapter 3, active surveillance in the form of screening household members of febrile patients for exposure to Brucella spp. was implemented in the NCA. Screening household members of febrile patients with acute brucellosis led to identification of additional acute cases. However, the study did not find a significant association between the Brucella spp. exposure of household members and the household member who sought care at hospital. In Chapter 4, Bayesian latent class analyses were used to evaluate the Rose Bengal plate test (RBT) and the competitive enzyme-linked immunosorbent assay (cELISA) for the diagnosis of livestock brucellosis in northern Tanzania. Sensitivity was variable across livestock models, RBT sensitivity was comparable to cELISA in the bovine model and greater than cELISA in ovine and caprine models. RBT and cELISA specificity was essentially comparable in all livestock models. Conducting parallel RBT and cELISA testing optimised diagnostic test performance in all livestock models. These novel findings can inform the development and implementation of effective, evidence-based brucellosis prevention and control measures in SSA. Improved knowledge of acute human brucellosis risk factors is important in understanding temporally relevant risks associated with active infection and is a vital tool in developing interventions that prevent transmission. Active surveillance by screening household members requires further study but may prove too resource-intensive for routine implementation in Tanzania. However, it can provide valuable data on disease burden for the population that do not reach a healthcare facility, as well as assist in targeting prevention and control measures towards high-risk populations. In livestock, a parallel RBT and cELISA diagnostic testing approach, potentially implemented at the herd/flock level, would be more effective than using either test alone or serial approaches. Using these data, identification of a national sampling and testing approach can guide the development of a surveillance strategy which is a crucial step towards improving our understanding of brucellosis burden across livestock-keeping settings in Tanzania and wider SSA

Healthy animals, healthy people: lived experiences of zoonotic febrile Illness in northern Tanzania

In the recognition that 75 percent of all emerging human infectious diseases in the past three decades originated in animals, many prominent veterinary and human health scientists have subscribed to the ‘One Health’ approach as a basis for redressing human diseases, animal diseases and environmental degradation worldwide (Rock et al., 2009). At its core, ‘One Health’ recognises the interconnectedness of humans, animals and the environment and thus calls for cross-sectoral, collaborative and integrative approaches to reducing disease burdens that arise at this interface. However, while the approach appears to be all encompassing in terms of interdisciplinary science, scant attention has been paid to the relationship between disease and society (Dzingirai et al., 2017). Endemic zoonoses, for example, disproportionately affects those in underprivileged communities and has significant impacts on rural livelihoods (Halliday et al., 2015). These diseases highlight how complex systems of health, poverty and politic collide, resulting in ‘structural violence’ (Galtung, 1969) and avoidable suffering for those who are already marginalised. Through adopting a mixed methods ethnography, this thesis offers insight into the lived experiences of livestock and human febrile illness (many of which are zoonotic) in an agropastoral community in northern Tanzania. I trace, in detail, the health seeking strategies undertaken to remedy illness, from recognition of symptoms through to engaging with public and veterinary health systems. By adopting a biosocial approach to this research, I am able to scrutinise the ways in which health-related behaviours are socially mediated. In doing so I uncover how ‘structural violence’ (Galtung, 1969) is deeply embedded within health systems and ultimately embodied by livestock keepers when pursuing health care for themselves and their livestock. This thesis hopes to provide a more critical theorisation of health seeking by highlighting the ways in which animal and human illness is experienced within prevailing social, political and economic dynamics. This has the potential to contribute to social science scholarship within One Health by taking a more nuanced view of the material conditions in which people live that shape their ability to effectively pursue animal and human health and wellbeing

WaArusha agro-pastoralist experiences with risk of febrile illness: an ethnographic study of social drivers of zoonoses and rural health-seeking behaviours in Monduli district, Northern Tanzania

Zoonoses are a major cause of febrile illness in people living with livestock in northern Tanzania. Early diagnosis and timely treatment influence the health outcomes of febrile patients, as any delay to care-seeking is significantly associated with complications leading to severe disease. However, little is known about lay experiences with zoonoses or febrile illness in these settings, and most studies tend to focus on the epidemiology of these diseases. In this thesis, I explore agro-pastoralist experiences of risk of febrile illness, understandings and framing of zoonotic health risks and local health-seeking behaviours. To do this, I spent ten months living amongst WaArusha agro-pastoralists in Naiti village, northern Tanzania, conducting ethnographic research using mixed-method approaches including household surveys, interviews and focus group discussions. The study finds that herders’ perceptions of zoonotic risks are shaped by external events that threaten their culture and social relationships, rather than expert narratives about zoonotic risks. Livestock and their product are central to the perceptions and management of risks among WaArusha families. Animal products particularly milk and meat-critical for household nutrition and for their therapeutic value- mediate between complex social relationships in ways that make it difficult to categorise them as “safe” or “unsafe”. Familiar zoonotic diseases such as anthrax, for example, which lead to high mortality in livestock and exhibit physical symptoms that locals can identify, are more accepted risks, whereas zoonoses that do not show physical symptoms such as brucellosis, the risks of which may be real, are less readily accepted as risks to human health. However, it does not follow that people take health-enhancing decisions to minimise harm, like changing their eating habits or visiting a doctor when illness occurs. Rather, people adopt approaches which appear, from an outsider perspective, to have both rational and irrational elements, and which are influenced by issues such as trust and practicality. Expert framings of risk and prescriptions for managing zoonotic risk, therefore, can only work when constructed alongside and in conjunction with lay beliefs. Not doing so results in parallel worlds where lay people are blamed by experts for “causing” their own sickness whilst at the same time expert authorities continue to be distrusted by local people, which in turn results in ineffective interventions

Public health at the margins: local realities and the control of neglected tropical diseases in Eastern Africa

Neglected Tropical Diseases (NTDs) are both causes and manifestations of poverty in developing countries. Recent advocacy efforts have increased the profile of NTDs, and led to bold new control and elimination targets set for 2020 by the World Health Organisation. However there are multifaceted challenges in effectively implementing NTD interventions in resource-poor contexts that need to be understood and engaged. While there is a growing call by researchers and international agencies for a science of global health delivery to understand these complexities, the exact nature of this science remains contested. This thesis contributes to these debates by advancing a critical social science perspective on the factors that mediate intervention effectiveness for NTD control. Grounded in a social constructivist approach using mixed methods, it critiques prevailing orthodoxies by unpacking the nature, processes and outcomes of three large-scale NTD prevention programmes in Eastern Africa. Focused on different diseases, these case studies represent different types of intervention approaches: top-down, participatory and public-private partnership. The thesis traces the social, technical and environmental processes that mediate the delivery, adoption and use of particular health technologies, such as pit latrines, insecticides and vaccination. Together, these case studies reveal surprisingly similar reasons for why many interventions do not perform according to expectations. Despite new approaches that claim to overcome stereotypical challenges of top-down planning, narrow technocratic perspectives continue to play a defining role in maintaining disjunctions between global aspirations, local realities and intervention outcomes. New perspectives and changes in orientation are needed that emphasise flexibility, learning and adaptability to local contexts. Towards this end, the thesis outlines a conceptual framework based on a comparative analysis of the case studies that highlights five interrelated domains where effectiveness is determined: geographical/livelihood variation, local agency, incentives, the socio-materiality of technology and planning/governance. I argue that addressing the shortcomings of contemporary interventions requires that programme planners actively engage these domains by seeking to “order complexity.” Greater integration of social science perspectives into the management of NTD programmes would provide significant benefit. In these ways, the thesis contributes to wider debates about the nature of global health interventions and the influence of local contexts in mediating efforts to improve the health and wellbeing of the world’s poor and marginalised

Global health - a challenge for interdisciplinary research

Human, animal and plant health is a field of work which offers opportunities for inter- and trans-disciplinary research. The whole topic bridges the natural and social sciences. Today, in a world of global environmental change it is widely recognized that human societies and their wellbeing depend on a sustainable equilibrium of ecosystem services and the possibility of cultural adaptation to global environmental change. The need to identify and quantify health risks related to global environmental change is now one of the most important challenges of humankind. Describing spatial (geographic, intra/inter-population) and temporal differences in health risks is an urgent task to understand societies’ vulnerabilities and priorities for interventions better. The Göttingen International Health Network (GIHN) is a research and teaching network in relation to this cross-cutting topic. The book provides a collection of articles which contribute to this issue of overriding importance and presents an overview of the GIHN launch event

Global health

Human, animal and plant health is a field of work which offers opportunities for inter- and trans-disciplinary research. The whole topic bridges the natural and social sciences. Today, in a world of global environmental change it is widely recognized that human societies and their wellbeing depend on a sustainable equilibrium of ecosystem services and the possibility of cultural adaptation to global environmental change. The need to identify and quantify health risks related to global environmental change is now one of the most important challenges of humankind. Describing spatial (geographic, intra/inter-population) and temporal differences in health risks is an urgent task to understand societies’ vulnerabilities and priorities for interventions better. The Göttingen International Health Network (GIHN) is a research and teaching network in relation to this cross-cutting topic. The book provides a collection of articles which contribute to this issue of overriding importance and presents an overview of the GIHN launch event

Leptospirosis in northern Tanzania: exploring the role of rodents and ruminant livestock in a neglected public health problem

Leptospirosis is an important but neglected zoonotic disease that is often overlooked in Africa. Although comprehensive data on the incidence of human disease are lacking, robust evidence of infection has been demonstrated in people and animals from all regions of the continent. However, to date, there are few examples of direct epidemiological linkages between human disease and animal infection. In East Africa, awareness of the importance of human leptospirosis as a cause of non-malarial febrile illness is growing. In northern Tanzania, acute leptospirosis has been diagnosed in 9% of patients with severe febrile illness compared to only 2% with malaria. However, little is known about the relative importance of different potential animal hosts as sources of human infection in this area. This project was established to investigate the roles of rodents and ruminant livestock, important hosts of Leptospira in other settings, in the epidemiology of leptospirosis in northern Tanzania. A cross-sectional survey of rodents living in and around human settlements was performed alongside an abattoir survey of ruminant livestock. Unusual patterns of animal infection were detected by real-time PCR detection. Renal Leptospira infection was absent from rodents but was detected in cattle from several geographic areas. Infection was demonstrated for the first time in small ruminants sub-Saharan Africa. Two major Leptospira species and a novel Leptospira genotype were detected in livestock. L. borgpetersenii was seen only in cattle but L. kirschneri infection was detected in multiple livestock species (cattle, sheep and goats), suggesting that at least two distinct patterns of Leptospira infection occur in livestock in northern Tanzania. Analysis of samples from acute leptospirosis in febrile human patients could not detect Leptospira DNA by real-time PCR but identified social and behavioural factors that may limit the utility of acute-phase diagnostic tests in this community. Analysis of serological data revealed considerable overlap between serogroups detected in cattle and human leptospirosis cases. Human disease was most commonly attributed to the serogroups Mini and Australis, which were also predominant reactive serogroups in cattle. Collectively, the results of this study led to the hypothesis that livestock are an important reservoir of Leptospira infection for people in northern Tanzania. These results also challenge our understanding of the relationship between Leptospira and common invasive rodent species, which do not appear to maintain infection in this setting. Livestock Leptospira infection has substantial potential to affect the well-being of people in East Africa, through direct transmission of infection or through indirect effects on food production and economic security. Further research is needed to quantify the impact of livestock leptospirosis in Africa and to develop effective interventions for the control of human and animal disease