Carnivore parvovirus ecology in the Serengeti ecosystem: vaccine strains circulating and new host species identified

Carnivore parvoviruses infect wild and domestic carnivores and cross- species transmission is believed to occur. However, viral dynamics are not well understood nor the consequences to wild carnivore populations of the introduction of new strains into wild ecosystems. To clarify the ecology of these viruses in a multi-host system such as the Serengeti ecosystem and identify potential threats for wildlife conservation we analyzed, through real-time PCR, 152 samples belonging to 14 wild carnivore species and 62 samples from healthy domestic dogs. We detected parvovirus DNA in several wildlife tissues. Of the wild carnivore and domestic dog samples tested, 13% and 43%, respectively, were positive for carnivore parvovirus infection, but little evidence of transmission between the wild and domestic carnivores was detected. Instead, we describe two different epidemiological scenarios with separated routes of transmission: first, an endemic feline parvovirus (FPV) route of transmission maintained by wild carnivores inside the Serengeti National Park (SNP); and second, a canine parvovirus (CPV) route of transmission among domestic dogs living around the periphery of the SNP. Twelve FPV sequences were characterized, new host-virus associations involving wild dogs, jackals and hyaenas were discovered and our results suggest mutations in the fragment of the gene were not required to infect different carnivore species. In domestic dogs, six sequences belonged to the CPV-2a strain, whilst 11 belonged to the CPV-2 vaccine-derived strain. This is the first description of a vaccine-derived parvovirus strain being transmitted naturally. IMPORTANCE: Carnivore parvoviruses are widespread among wild and domestic carnivores, which are vulnerable to severe disease under certain circumstances. The findings from this study, which further the understanding of carnivore parvovirus epidemiology, suggest that feline parvoviruses are endemic in wild carnivores in the Serengeti National Park (SNP); further, that canine parvoviruses are present in the dog population living around the SNP, with little evidence of transmission into wild carnivore species; and finally, that the detection of vaccine-derived virus (described here for the first time circulating naturally in domestic dogs) highlights the importance of performing epidemiological research in the region

Evaluation of a Direct, Rapid Immunohistochemical Test for Rabies Diagnosis

A direct rapid immunohistochemical test (dRIT) was evaluated under field and laboratory conditions to detect rabies virus antigen in frozen and glycerol-preserved field brain samples from northwestern Tanzania. Compared to the direct fluorescent antibody test, the traditional standard in rabies diagnosis, the dRIT was 100% sensitive and specific

After-action review of rabies and anthrax outbreaks multisectoral response in Tanzania, challenges and lessons

After-action review uses experiences gained from past events to adopt best practices, thereby improving future interventions. In December 2016 and late 2018, the government of Tanzania with support from partners responded to anthrax and rabies outbreaks in Arusha and Morogoro regions respectively. The One Health Coordination Desk (OHCD) of the Prime Minister’s Office (PMO) later coordinated after-action reviews to review the multi-sectoral preparedness and response to the outbreaks. To establish and describe actions undertaken by the multi-sectoral investigation and response teams during planning and deployment, execution of field activities, and outbreak investigation and response, system best practices and deficiencies. These were cross-sectional surveys. Semi-structured, open and closed-ended questionnaire and focus group discussions were administered to collect information from responders at the national and subnational levels. It was found that the surveillance and response systems were weak at community level, lack of enforcement of public health laws including vaccination of livestock and domestic animals and joint preparedness efforts were generally undermined by differential disease surveillance capacities among sectors. Lack of resources in particular funds for supplies, transport and deployment of response teams contributed to many shortfalls. The findings underpin the importance of after-action reviews in identifying critical areas for improvement in multi-sectoral prevention and control of disease outbreaks. Main sectors under the coordination of the OHCD should include after action reviews in their plans and budget it as a tool to continuously assess and improve multi-sectoral preparedness and response to public health emergencies

Serologic Surveillance of Anthrax in the Serengeti Ecosystem, Tanzania, 1996–2009

Bacillus anthracis, the bacterium that causes anthrax, is responsible for varying death rates among animal species. Difficulties in case detection, hazardous or inaccessible carcasses, and misdiagnosis hinder surveillance. Using case reports and a new serologic assay that enables multispecies comparisons, we examined exposure to and illness caused by B. anthracis in different species in the Serengeti ecosystem in Tanzania during 1996–2009 and the utility of serosurveillance. High seroprevalence among carnivores suggested regular nonfatal exposure. Seropositive wildebeest and buffalo showed that infection was not invariably fatal among herbivores, whereas absence of seropositivity in zebras and frequent detection of fatal cases indicated high susceptibility. Exposure patterns in dogs reflected known patterns of endemicity and provided new information about anthrax in the ecosystem, which indicated the potential of dogs as indicator species. Serosurveillance is a valuable tool for monitoring and detecting anthrax and may shed light on mechanisms responsible for species-specific variability in exposure, susceptibility, and mortality rates

Cross‐species transmission and evolutionary dynamics of canine distemper virus during a spillover in African lions of Serengeti National Park

The outcome of pathogen spillover from a reservoir to a novel host population can range from a “dead‐end” when there is no onward transmission in the recipient population, to epidemic spread and even establishment in new hosts. Understanding the evolutionary epidemiology of spillover events leading to discrete outcomes in novel hosts is key to predicting risk and can lead to a better understanding of mechanisms of emergence. Here we use a Bayesian phylodynamic approach to examine cross‐species transmission and evolutionary dynamics during a canine distemper virus spillover event causing clinical disease and population decline in an African lion population (Panthera leo) in the Serengeti Ecological Region between 1993 and 1994. Using 21 near‐complete viral genomes from four species we found that this large‐scale outbreak was likely ignited by a single cross‐species spillover event from a canid reservoir to non‐canid hosts less than one year before disease detection and explosive spread of CDV in lions. Cross‐species transmission from other non‐canid species likely fueled the high prevalence of CDV across spatially structured lion prides. Multiple lines of evidence suggest that spotted hyenas (Crocuta crocuta) could have acted as the proximate source of CDV exposure in lions. We report thirteen nucleotide substitutions segregating CDV strains found in canids and non‐canids. Our results are consistent with the hypothesis that virus evolution played a role in CDV emergence in non‐canid hosts following spillover during the outbreak, and suggests that host barriers to clinical infection can limit outcomes of CDV spillover in novel host species

Transmission ecology of canine parvovirus in a multi-host, multi-pathogen system

Understanding multi-host pathogen maintenance and transmission dynamics is critical for disease control. However, transmission dynamics remain enigmatic largely because they are difficult to observe directly, particularly in wildlife. Here, we investigate the transmission dynamics of canine parvovirus (CPV) using state-space modelling of 20-years of CPV serology data from domestic dogs and African lions in the Serengeti ecosystem. We show that, although vaccination reduces the probability of infection in dogs, and despite indirect enhancement of population seropositivity as a result of vaccine shedding, the vaccination coverage achieved has been insufficient to prevent CPV from becoming widespread. CPV is maintained by the dog population and has become endemic with ~3.5-year cycles and prevalence reaching ~80%. While the estimated prevalence in lions is lower, peaks of infection consistently follow those in dogs. Dogs exposed to CPV are also more likely to become infected with a second multihost pathogen, canine distemper virus. However, vaccination can weaken this coupling raising questions about the value of monovalent versus polyvalent vaccines against these two pathogens. Our findings highlight the need to consider both pathogen- and host-level community interactions when seeking to understand the dynamics of multi-host pathogens and their implications for conservation, disease surveillance and control programmes

Molecular species identification of bushmeat recovered from the Serengeti ecosystem in Tanzania.

This research article published by PLOS ONE, 2020Bushmeat harvesting and consumption represents a potential risk for the spillover of endemic zoonotic pathogens, yet remains a common practice in many parts of the world. Given that the harvesting and selling of bushmeat is illegal in Tanzania and other parts of Africa, the supply chain is informal and may include hunters, whole-sellers, retailers, and individual resellers who typically sell bushmeat in small pieces. These pieces are often further processed, obscuring species-identifying morphological characteristics, contributing to incomplete or mistaken knowledge of species of origin and potentially confounding assessments of pathogen spillover risk and bushmeat offtake. The current investigation sought to identify the species of origin and assess the concordance between seller-reported and laboratory-confirmed species of origin of bushmeat harvested from in and around the Serengeti National Park in Tanzania. After obtaining necessary permits, the species of origin of a total of 151 bushmeat samples purchased from known intermediaries from 2016 to 2018 were characterized by PCR and sequence analysis of the cytochrome B (CytB) gene. Based on these sequence analyses, 30%, 95% Confidence Interval (CI: 24.4-38.6) of bushmeat samples were misidentified by sellers. Misreporting amongst the top five source species (wildebeest, buffalo, impala, zebra, and giraffe) ranged from 20% (CI: 11.4-33.2) for samples reported as wildebeest to 47% (CI: 22.2-72.7) for samples reported as zebra although there was no systematic bias in reporting. Our findings suggest that while misreporting errors are unlikely to confound wildlife offtake estimates for bushmeat consumption within the Serengeti ecosystem, the role of misreporting bias on the risk of spillover events of endemic zoonotic infections from bushmeat requires further investigation

The feasibility of canine rabies elimination in Africa: dispelling doubts with data

<p><b>Background:</b> Canine rabies causes many thousands of human deaths every year in Africa, and continues to increase throughout much of the continent.</p> <p><b>Methodology/Principal Findings:</b> This paper identifies four common reasons given for the lack of effective canine rabies control in Africa: (a) a low priority given for disease control as a result of lack of awareness of the rabies burden; (b) epidemiological constraints such as uncertainties about the required levels of vaccination coverage and the possibility of sustained cycles of infection in wildlife; (c) operational constraints including accessibility of dogs for vaccination and insufficient knowledge of dog population sizes for planning of vaccination campaigns; and (d) limited resources for implementation of rabies surveillance and control. We address each of these issues in turn, presenting data from field studies and modelling approaches used in Tanzania, including burden of disease evaluations, detailed epidemiological studies, operational data from vaccination campaigns in different demographic and ecological settings, and economic analyses of the cost-effectiveness of dog vaccination for human rabies prevention.</p> <p><b>Conclusions/Significance:</b> We conclude that there are no insurmountable problems to canine rabies control in most of Africa; that elimination of canine rabies is epidemiologically and practically feasible through mass vaccination of domestic dogs; and that domestic dog vaccination provides a cost-effective approach to the prevention and elimination of human rabies deaths.</p&gt

Population size estimates and distribution of the African elephant using the dung surveys method in Rubondo Island National Park, Tanzania

Research Article published by International Journal of Biodiversity and Conservation Vol. 8(6), June 2016A study to estimate population size and distribution of elephants in the Rubondo Island National Park (RINP) was conducted between March and July 2014. It involved elephant dung survey methods. In estimating elephant dung pile density, a total of 217 dung piles were enumerated in 58 transects (each 1 km). The on-site dung decay rate computed from 100 marked fresh dung piles was estimated to be 0.01542 per day. By combining estimated dung pile density, on-site decay rate and defecation rate of 17 dung piles per day, the study found an estimate of about 102 elephants (95% CI, 72-144). Furthermore, results of this study indicate that, elephants were found to be more concentrated on the central and northern zones, which are the areas of the park that have some open glades allowing elephant to access the area easily to lake shores. The information generated from the study can be incorporated into setting up future management strategies for elephant conservation in RINP