IgM seroprevalence all pigs 2017-2022
The number of samples tested for IgM from 28 October 2017 – 23 December 2022 was highest in Gorakhpur division (Gorakhpur, Kushinagar, Deoria and Maharajganj districts, n = 1781; 54%; Figure S6). Throughout the study period, the district with the highest IgM seroprevalence was Basti (19.4%; 95% CI 26.3-13.6), closely followed by Azamgarh and Ballia, and the lowest was Maharajganj (4.8%; 95% CI 2.7-7.8; Figure S7). Annual peak seroprevalence varied between districts, although peaks appeared consistently in 2018 in the northern and western districts (Basti, Kushinagar, Maharajganj, Sant Kabir Nagar, Siddarthnagar; Figure 3) as well as potentially the western district of Azamgarh (serology from 2018 only). The highest annual peak was observed in Gorakhpur in 2017 (69.5%; 95% CI 40.4-89.9%). Seroprevalence of IgM was similar between age groups, and a pattern of seroprevalence by age between districts was not observed (Figure S8).