IgG seroprevalence by age group, 2013-2022
The number of samples tested for IgG in pigs (4-5m) was highest in
Gorakhpur division (n = 644; 61%; Figure S9). The highest and lowest
recorded IgG seroprevalences in young pigs throughout the study period
were 27.2% (95% CI 19.1-36.7) and 2% (95% CI 0.00-14.7) in Basti and
Azamgarh, respectively (Figure S10). Annual seroprevalence of IgG varied
throughout the study period in all districts (Figure S11).
No significant linear trend was observed in the time series of monthly
IgG seroprevalence in young pigs (overall change in seroprevalence =
-1.3%/month [95% CI -3.2—0.5], P = 0.15; Figure 5). Time series
decomposition again demonstrated a marked seasonal pattern with three
annual peaks in March, May, and September (summer and monsoon seasons;
Figure 5). Consistent with IgM seroprevalence, the greatest variation in
IgG seroprevalence in young pigs was due to the remainder (random)
portion of the decomposed time series.