Molecular epidemiology of foot-and-mouth disease virus in the context of transboundary animal movement in the far north region of Cameroon

Authors: BERTRAM, M - Oak Ridge Institute For Science And Education (ORISE); BRAVO DE RUEDA, C - Oak Ridge Institute For Science And Education (ORISE); GARABED, R - The Ohio State University; DICKMU JUMBO, S - Lanavet; MORITZ, M - The Ohio State University; Pauszek, Steven; ABDOULKADIRI, S - Lanavet; Rodriguez, Luis; Arzt, Jonathan

Submitted to: Frontiers in Veterinary Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2018
Publication Date: 12/14/2018
Citation: Bertram, M., Bravo De Rueda, C., Garabed, R., Dickmu Jumbo, S., Moritz, M., Pauszek, S.J., Abdoulkadiri, S., Rodriguez, L.L., Arzt, J. 2018. Molecular epidemiology of foot-and-mouth disease virus in the context of transboundary animal movement in the far north region of Cameroon. Frontiers in Veterinary Infectious Diseases. https://doi.org/10.3389/fvets.2018.00320.
DOI: https://doi.org/10.3389/fvets.2018.00320

Interpretive Summary: Foot and mouth disease (FMD), caused by FMD virus (FMDV), is an important livestock disease that causes substantial animal health problems and economic losses in many countries in Africa and Asia, where the disease is endemic. Transboundary animal movement (movement of animals across country borders) is an important mechanism for disease spread, however its role in FMDV epidemiology has not been fully investigated. The purpose of this study was to investigate the role of transboundary trade cattle in the epidemiology of FMDV in the Far North Region of Cameroon. Samples were collected from apparently healthy transboundary cattle at border checkpoints and from clinically affected native cattle in the region. FMDV genetic sequences obtained from samples in this study were compared to each other and to other sequences collected in the region, and broad patterns of transmission were deduced for FMDV serotypes A, O, and SAT2. This study contributes to the understanding of the role of transboundary trade animals in FMDV epidemiology in Central Africa and will help to inform regional FMDV control programs.

Technical Abstract: Transboundary movement of animals is an important mechanism for foot-and-mouth disease virus (FMDV) spread in endemic regions, such as Cameroon. Several transboundary animal trade routes cross the Far North Region of Cameroon, and cattle moved on foot along these routes often come in contact with native (sedentary and transhumant) herds. The purpose of this study was to investigate the role of transboundary trade cattle in the epidemiology of FMDV in the Far North Region of Cameroon. A total of 582 oropharyngeal fluid (OPF) samples were collected from asymptomatic transboundary trade cattle at official border check points and 57 vesicle epithelial tissues were collected from clinically affected native cattle in the Far North Region of Cameroon during 2010-2014. VP1 sequences were obtained from 6 transboundary OPF samples (4 serotype O, 2 serotype SAT2) and 19 native epithelial tissue samples (7 serotype O, 3 serotype SAT2, 9 serotype A). FMDV serotype O viruses grouped into two topotypes (East Africa-3 and West Africa), and phylogenetic analyses suggested a pattern of continuous transmission in the region. Serotype SAT2 viruses belonged to a single topotype (VII), and phylogenetic analysis suggested a pattern of repeated introductions in the region. Serotype A viruses belonged to topotype AFRICA/G-IV, and the pattern of transmission was unclear. Spearman correlation analysis of transboundary and native sequences obtained in this study showed a correlation between genetic distance and time for serotype O (0.71, p-value=0.003) and between genetic distance and geographic distance for serotype SAT2 (0.54, p-value=0.1). These data suggest that transboundary trade cattle participate in the transmission of FMDV in the Far North Region of Cameroon, however the dynamics and direction of transmission could not be determined in this study. Results of this study contribute to the understanding of transboundary FMDV epidemiology in Central Africa and will help to inform control programs in Cameroon and in the region.