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Research Project: The Impact of Acute Subclinical Foot-and-Mouth Disease Virus in Kenyan Cattle

Location: Foreign Animal Disease Research

Project Number: 3022-32000-064-009-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 30, 2018
End Date: Sep 29, 2022

Foot-and-Mouth Disease Virus (FMDV) is a highly contagious disease affecting wild and domestic cloven-hoofed animals. The disease, which is endemic in Africa, constitutes a substantial burden for subsistence livestock production and prevents trade. In Kenya, 80-90% of the country’s beef production comes from smallholder farmers. The occurrence of the disease therefore, substantially impacts the livelihood and food supply of its people. In addition to clinical Foot-and-Mouth Disease (FMD), it has been shown that subclinical FMDV infection contributes to the circulation of the virus in endemic settings. The extent of subclinical acute, or new, infections is poorly understood. Recent studies have shown that a substantial portion of FMDV infection leads to acute subclinical infection without ever causing the disease. This phenomenon has recently been observed in Central Kenya. Activities in this research project include the characterization of the extent of acute subclinical FMD circulating among different types of productive systems in Kenya. Specifically, we will characterize how subclinical FMDV infection contributes to disease spread and virus evolution in the region. Specific objectives include: 1. Establish a surveillance system to obtain animal samples and epidemiological data associated with subclinical FMDV infection. 2. Determine the prevalence and strains of FMDV circulating clinically and sub clinically in Kenya. 3. Characterize the epidemiological factors influencing the clinical and subclinical circulation of FMDV. 4. Genetically and antigenically characterize FMDV strains and determine their relationship to vaccine strains.

1. A sample protocol will be developed and deployed in areas where FMD is hyperendemic. Specific herds will be identified and sampled during both clinical outbreaks and in the absence of an outbreak. Selected herds will be sampled serially in a longitudinal study to determine the extent of subclinical viral circulation in these regions. 2. Serological surveys and probing testing will be conducted on various herds representing distinct production systems in Kenya with the emphasis on small holder farms and transhumance migratory herds. This information will be used to identify the prevalence of active infection in the different regions and animal populations. 3. Epidemiological surveys will be administered to animal owners to enable inference of associations between detected viruses and herd management data. Limited sample collections from regional wildlife will be leveraged. 4. Samples will be tested by real-time PCR, virus isolation, antigen ELISA, and serological ELISA testing to detect structural and non-structural FMDV protein antibodies. Field samples from acute and subclinical infections will be sent to ARS, PIADC for real-time RT-PCR, virus isolation and strain characterization by sequence acquisition and analysis. Spatial epidemiological and phylogenetic analysis will be performed by collaborators from the University of Minnesota.