Serotype Specificity of Antibodies against Foot-and-Mouth Disease Virus in Cattle in Selected Districts in Uganda

Abstract

Uganda had an unusually large number of foot-and-mouth disease (FMD) outbreaks in 2006, and all clinical reports were in cattle. A serological investigation was carried out to confirm circulating antibodies against foot-and-mouth disease virus (FMDV) by ELISA for antibodies against non-structural proteins and structural proteins. Three hundred and forty-nine cattle sera were collected from seven districts in Uganda, and 65% of these were found positive for antibodies against the non-structural proteins of FMDV. A subset of these samples were analysed for serotype specificity of the identified antibodies. High prevalences of antibodies against non-structural proteins and structural proteins of FMDV serotype O were demonstrated in herds with typical visible clinical signs of FMD, while prevalences were low in herds without clinical signs of FMD. Antibody titres were higher against serotype O than against serotypes SAT 1, SAT 2 and SAT 3 in the sera investigated for serotype-specific antibodies. Only FMDV serotype O virus was isolated from one probang sample. This study shows that the majority of the FMD outbreaks in 2006 in the region studied were caused by FMDV serotype O; however, there was also evidence of antibodies to both SAT 1 and SAT 3 in one outbreak in a herd inside Queen Elizabeth national park area.

Application of the Ceditest® FMDV type O and FMDV-NS enzyme-linked immunosorbent assays for detection of antibodies against Foot-and-mouth disease virus in selected livestock and wildlife species in Uganda

“…Thus, this result supports the preceding conclusion (Table 1), and half of these samples came from a herd with higher titers of antibodies against the SAT serotypes than against serotype O (K1), 14 confirming the results from Ks12 sampled in 2006, while the remaining 18 samples were dispersed among 10 of the 16 sampled herds. 14 The NSP test, like other commercially available test kits for antibodies against the NSPs of FMDV, have important applications in differentiating infected from vaccinated animals, 19 but this usage may be complicated by nonpurified FMDV vaccines inducing antibodies against the NSPs. The differences between the performances of the NSP test and the SP-O test in small ruminants followed the results in cattle, but were not statistically significant due to low numbers of positives.…”

“…In the 2006 PO sampling, on-farm seroprevalence in the NSP and SP-O tests were generally comparable 14 ; however, 1 out of 22 cattle herds (Ks12) with a history of recent clinical signs of FMD had much higher prevalence of antibodies against FMDV in the NSP test than in the SP-O test. 14 Analysis of serotype-specificity of FMDV antibodies of 20 heads of cattle from this herd using SPBEs for all 7 serotypes revealed that these cattle exclusively had antibodies against the SAT serotypes ( Table 3).…”

“…14 Analysis of serotype-specificity of FMDV antibodies of 20 heads of cattle from this herd using SPBEs for all 7 serotypes revealed that these cattle exclusively had antibodies against the SAT serotypes ( Table 3). Most of these 20 samples had low antibody titers against serotypes SAT2 and SAT3; however, 1 animal had a titer of 80 for antibodies against SAT2, 3 animals had titers of 80-160 against SAT3, and 1 animal had a titer of 640 against SAT1.…”

“…14, 15 Three hundred four goat sera and 88 sheep sera were collected from the same farms or villages during these sampling trips. 4 Testing for antibodies against FMDV was done using the NSP a and SP-O b tests according to the manufacturer's instructions.…”

“…Selected samples, mostly positive for antibodies against NSPs, were screened at dilution 1:5 using an in-house SPBE for antibodies against FMDV serotype O (SPBE-O) with a cutoff of 50% as previously described. 4 The 15 were examined in SPBEs for antibodies against all 7 serotypes of FMDV as previously described. 4 Differences between groups were tested for statistical significance using chi-square, and differences between seroprevalence obtained with the NSP and SP-O tests were analyzed using McNemar test in a spreadsheet program.…”