Results
Across all animals, 3.4% (9/262, 95% CI 1.58-6.42%) had detectable FMDV RNA in oral and/or nasal swabs. When all swab types (oral, nasal and pharyngeal) were included, 7.3% (19/262, 95% CI 4.42-11.09%) of all animals in both countries had detectable FMDV RNA on at least one swab (Table 1), including 10.4% (5/48, 95% CI 3.47-22.66%) buffalo and 6.0% (5/84, 95% CI 1.96-13.34%) cattle in Laos, and 0% (0/5, 95% CI 0.00-52.18%) buffalo and 7.2% (9/125, 95% CI 3.34-13.23%) cattle in Myanmar. No animals had any lesions or clinical signs consistent with FMD. The most common site of detection in animals with a positive real-time RT PCR CT value was dorsal nasopharyngeal (14/19 animals), followed by oral (6/19 animals) and then nasal (4/19 animals). Animals positive on at least one swab were significantly more seropositive (61.9% seropositive, 13/21) compared with animals from the whole group (101/262, 38.5%) (Chi-square statistic = 4.4084, p-value = 0.036). All environmental control swabs were negative by real time PCR.
Fifty animals in the study group were male (19%), and the rest were female except for one animal with unrecorded sex. Sex was not a significant factor in whether there were one or more positive swabs (1 positive male to 19 positive total) or 5.3%, Fisher’s exact test 95% CI (0.01-1.46), p-value = 0.137. More young animals (under 24 months of age) were sampled in Laos (n =37) compared to Myanmar (n =4). The mean age of animals that were positive on one or more swab was 4.5 years, and age was not significantly different compared to animals that were negative on all swabs (Mann-Whitney U test, W = 2545.5, p-value = 0.4532). Animals with positive RT-PCR results were spread across multiple traders and across multiple nights.