The continued emergence of high-consequence zoonotic pathogens is a clear and present threat to human and animal health globally. In the past decade alone numerous outbreaks, most notably the 2013-2016 West Africa Ebola virus disease epidemic1, have demonstrated the severely impacts of these diseases on overall population health, health care workers, and the fundamental economic stability of entire countries and regions1. Other viral zoonotic pathogens may have less global notoriety but nonetheless present a high disease burden in endemic areas and have the potential to expand their geographic range in coming years due to human activity, the influences of climate change on disease vectors, and geopolitical instability. Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne virus that can cause fever, bleeding, and high case fatality rates in people. The virus has a complex ecology that remains poorly understood in many areas of the world, particularly in Africa. Ecological investigation of the virus is vital for understanding the distribution and transmission of viruses both at a population and an individual level. Population level surveillance of CCHFV in wildlife, livestock and tick can shed light on patterns of viral circulation and aid in identification of risk factors associated with infection. In Tanzania, studies on CCHFV have mainly been in human and livestock in the north. Epidemiological information regarding CCHFV and other emerging pathogens is scarce in other parts of the country. Thus, the initial part of this study is designed to establish seroprevalence and genetic diversity of CCHFV in selected humans, livestock, and wildlife interface areas in Tanzania. The findings will contribute to a better understanding of the roles that livestock, wildlife and ticks of different species play in the maintenance and transmission of CCHFV, ultimately aiding in the development of targeted public health interventions and strategies for transmission, prevention and control.

Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne zoonotic pathogen responsible for severe human hemorrhagic fever disease characterized by fever, weakness, myalgia, and hemorrhagic signs. The CCHFV has a broad mammalian host range and circulates primarily in a tick-vertebrate-tick cycle, with Hyalomma spp. ticks identified as the natural vector and reservoir. The majority of reported human cases are linked to exposure to Hyalomma spp. as the primary tick vector often found on domestic livestock. Our preliminary serological surveys conducted in Iringa and Morogoro regions between 2020-2021 have demonstrated a high CCHFV exposure (approximately 30% in cattle) across these study areas. However, the molecular testing of the primary vector tick genera (Hyalomma spp.) collected in areas where cattle herds were tested for CCHFV yielded negative results. To further help understand the ecology of CCHFV transmission in the study areas we extended testing to include Amblyomma spp. collected directly from cattle between 2020-2021 by RT-qPCR assays. Despite screening over 900 individual ticks, no CCHFV positive specimens were detected. This data indicates that the ecology of CCHF in this region may be more complex than originally hypothesized, with other tick genera and other livestock and wildlife species potentially serving as the drivers of CCHFV transmission. Overall, despite CCHFV's widespread impact, especially in endemic regions, the virus's epidemiology and ecology remain poorly understood in wildlife species in particular the rodents, hare and ground feeding birds at the human-livestock-wildlife interface areas. This study therefore aims to evaluate the ecology and genetic diversity of CCHFV in selected wildlife species and ticks from the human-livestock-wildlife interface areas of Tanzania.

i. To characterize tick composition and seroprevalence and genetic lineage of CCHFV in selected wildlife species in interface areas. Hypotheses: Those wild hares, rodents, and ground-feeding birds that interface with livestock will show evidence of higher seroconversion to anti-CCHFV antibodies compared to those with less contact. Additionally, CCHFV prevalence will be elevated in rodents and ground-dwelling birds compared to hares. ii. To determine biological and ecological factors influencing the risk of viral spillover, amplification, and spread to develop and parameterize ecological and epidemiological models to estimate exposure risk for CCHFV as an emerging pathogen. Hypotheses: Regions where wildlife and domestic animals interact will demonstrate an elevated risk of CCHFV spillover compared to regions with less interactions. Additionally, those regions associated with higher rainfall and vegetation will have higher numbers of ticks and therefore CCHFV.