The bird-level ND seroprevalence pooled across all samplings (adjusted for clustering by households) was 4.4%(95%CI 3.5-5.2). The bird-level ND seroprevalence in each of the three sampling periods (adjusted for clustering by household) was 3.0%(95%CI 2.0-4.0), 6.6%(95%CI 5.1-8.0) and 3.6 (95%CI 2.5-4.6), respectively. A total of 12.6%individual birds tested ND seropositive at least once over the total study period (95%CI 10.5-14.7).
The flock-level ND seroprevalence (at least one bird tested had antibodies against ND virus) pooled across all samplings was 15.9%(95%CI 13.5-18.3). A total of 35.3%flocks had a minimum of one bird being ND seropositive at least once over the study period.
The bird-level incidence rate for the period between the first and the second sampling and between the second and the third sampling was 5.6 (95%CI 4.1-7.5) and 0.5 (95%CI 0.5-3.8) per 10,000 bird-years-at-risk, respectively.
A total of 1134 serum samples from the last sampling period between June and August 2009 was tested for antibodies against AI virus. Only 4 samples tested Influenza A positive, indicating a bird-level seroprevalence level for Influenza A of 0.4%(CI 0.0-0.7%). These Influenza A positive samples were further tested for HI antibodies against AI virus subtypes of H5N1, H5N3, H7N3 and H9N2, but all tested negative, suggesting that the influenza antibodies in those four birds resulted from exposure to low pathogenic AI viruses of different H subtypes.
Our results indicate that village chickens in Timor-Lest茅 are exposed to ND virus; there was a higher risk of infection during the early months of 2009 than either immediately prior or subsequent to this. No evidence of infection of village chickens with H5, H7 or H9 AI viruses was detected in this study.