Identification of virus transmission networks to control key arboviral diseases in Kenya

• Applicant: Professorin Dr. Sandra Junglen
• Subject Area: Virology ; Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317308297

Arboviruses pose a tremendous burden on individuals, societies, and economies. While they often originate in Sub-Saharan Africa, there is little knowledge on the spectrum of causative viruses, their prevalence, and their social impact in these regions. The major goal of this collaborative project is a holistic understanding of key arboviral diseases in Kenya, including sources of outbreaks, infection-related impacts on humans, and societal conditions and consequences of arbovirus incidence. A strong focus in all stages of research is on training and capacity building for future independent research in Kenya. During the previous funding periods, we discovered a variety of arboviruses circulating in vectors, rodents, livestock and humans. Four of the most relevant findings are mentioned below. (i) Our findings on six previously unknown sandfly-borne phleboviruses greatly expanded the knowledge on the genetic diversity of phleboviruses. We have identified viruses in all known human pathogenic serocomplexes. The presence of such viruses in Sub-Saharan Africa was not known. (ii) We detected a previously unknown orbivirus, named Kaptombes virus (KPTV), in cattle. We isolated the virus from the serum of a clinically sick cow aged 2 to 3 years, presenting signs of lethargy. KPTV was identified in three additional animals collected in 2020 and 2021. Neutralizing antibodies against KPTV were found in 6% (12/200) of sera of ruminants. In-vivo infection of new-born mice induced body tremors, hind limb paralysis, and mortality. The data suggest the discovery of a novel pathogenic orbivirus in cattle. (iii) We showed that Ngari virus (NRIV), a mosquito-borne orthobunyavirus that causes severe febrile illness and hemorrhagic fever in humans and small ruminants, is actively circulating in Kenya. NRIV was detected during a cross-sectional survey in two pastoralist dominated dryland ecosystems and no symptoms of disease were observed in infected cattle, goat, and sheep. NRIV neutralizing reactivity in cattle, goats, and sheep were 41.6, 52.4, and 19%, respectively. (iv) We provided the first evidence that Chandipura virus (CHPV), a vesiculovirus known to cause encephalitis outbreaks with high mortality rates in India, is also circulating in sandflies in Kenya. In this final and last funding period, we will focus on NRIV and CHPV. Our key objectives are: (i) To provide information on Ngari, Bunyamwera and Batai viruses acute incidence and seroprevalence in livestock and humans, as well as on virus abundance in mosquito vectors. (ii) To assess the genetic diversity of CHPV and Chandipura-like viruses in sandflies and to assess acute and past CHPV infection rates in humans and livestock. (iii) To provide education, training, and capacity building in the fields of disease ecology and virology. Overall, the project aims to reduce arbovirus disease outbreaks locally and also globally by preventing geographic spread from seeding regions.

• DFG Programme: Research Grants
• International Connection: Kenya
• International Co-Applicant: David P Tchouassi, Ph.D.