Study on seroprevalence and serotyping of foot and mouth disease in Chad

Abstract

Foot and mouth disease (FMD) is a highly contagious viral disease that affects all Artiodactyla. Seven immunologically distinct serotypes of FMD virus (FMDV) exist. In Chad, although FMD is included in the list of diseases monitored by the Chadian Animal Disease Surveillance Network (REPIMAT), the epidemiological situation remains unclear. A serological survey was conducted in the cattle population in eight of the nine administrative regions of the country (those regions with the highest cattle densities), to evaluate the prevalence and serotypes of circulating FMDV. A total of 796 sera from randomly selected cattle were analysed at the World Organisation for Animal Health/Food and Agriculture Organization of the United Nations FMD Reference Laboratory at the Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), in Brescia (Italy). An enzyme-linked immunosorbent assay (ELISA), called 3ABC ELISA, was used to detect antibodies against non-structural proteins (NSPs), as well as a series of six competitive ELISAs to detect and serotype antibodies against the structural proteins of FMDV serotypes O, A, SAT 1, SAT 2, Asia 1 and C. Based on the detection of anti-NSP antibodies, the animal-level seroprevalence was 35.6% (95% confidence interval [CI]: 32.2-38.9) and the herd-level seroprevalence was 62.3% (95% CI: 53.0-71.5). FMD was present in all livestock administrative divisions surveyed, with a higher prevalence in southern regions, which are characterised by higher rainfall and humidity and more important transboundary animal movements. Cattle aged more than four years had a higher seroprevalence, which may be due to repeated exposure. Semi-sedentary farming and transhumance were also risk factors. Antibodies against serotypes A, O, SAT 1 and SAT 2 were detected.

Using a participatory qualitative risk assessment to estimate the risk of introduction and spread of transboundary animal diseases in scarce‐data environments

“…Studies in Chad, Niger and Uganda have shown that increased density of cattle and small ruminants is a risk factor of FMD spread (Munsey et al, 2019;Ouagal et al, 2018;Souley Kouato et al, 2018).…”

Molecular detection and adaptation of FMD virus serotype type O in BHK-21 cell line by RT-PCR

“…Foot-and-mouth disease virus (FMDV) is a tiny, non-enveloped, proactive, single-stranded RNA that belongs to the genus Aphthovirus under the Picornaviridae family (Malik et al, 2017). Seven immunologically unique FMDV serotypes such as A, O, C, Asia1, SAT-1, SAT-2, and SAT-3 are found worldwide (Ouagal et al, 2018). Except from Asia1, the other six FMDV serotypes were present in the African continent from 1993 to 2012 (Lloyd-Jones et al, 2017).…”

Seroprevalence and molecular characterization of foot‐and‐mouth disease virus in Chad

“…The incidence of FMD virus transmission is most likely related to animal mobility (Bertram, Bravo, et al, ; Bertram, Delgado, et al, ). In Chad, four serotypes have been identified: O, A, SAT1 and SAT2 (Gueme, ; Ouagal et al, , ; Ouagal, Hendrikx, Saegerman, & Berkvens, ). The circulation of these serotypes was reported in countries neighbouring Chad, such as Sudan, Cameroon, Niger and Nigeria (Abu Elzein, ; Bertram, Bravo, et al, ; Bertram, Delgado, et al, ; Ehizibolo et al, , ; Habiela, Alamin, Alamin, Raouf, & Ali, ; Habiela, Ferris, et al, ; Knowles, Bachanek‐Bankowska, et al, ; Kouato, Elliot, et al, ; Kouato, Souley, et al, ).…”

“…In Chad, four serotypes have been identified: O, A, SAT1 and SAT2 (Gueme, 1998;Ouagal et al, 2018Ouagal et al, , 2017Ouagal, Hendrikx, Saegerman, & Berkvens, 2010). The circulation of these serotypes was reported in countries neighbouring Chad, such as Sudan, Cameroon, Niger and Nigeria (Abu Elzein, 1983;Bertram, Bravo, et al, 2018;Bertram, Delgado, et al, 2018;Ehizibolo et al, 2017aEhizibolo et al, , 2017bHabiela, Alamin, Alamin, Raouf, & Ali, 2010;Habiela, Ferris, et al, 2010;Kouato, Elliot, et al, 2018;Kouato, Souley, et al, 2018).…”

“…In Chad, despite the endemicity of the disease, few studies have been carried out on seroprevalence (Ouagal et al, , ) and no studies on the molecular characterization of the FMDV have been yet published. That is why we decided to conduct a study to determine seroprevalence and characterize the serotypes of FMD viruses circulating in the area of the Pastoral Strengthening of Livestock in Chad (PREPAS) project.…”