A 5‐year dog cohort established in the Qilian Mountains from 2017 to 2021 was used to elucidate the spatiotemporal dynamics of serum F1 antibody titers and their significance for characterizing plague transmission in animal populations. A total of 1212 serum samples were collected, with an overall F1 seropositivity rate of 83.25% (1009/1212) and a geometric mean titer (GMT) of 1:191.33. Despite the persistently high seropositivity, the GMT exhibited marked seasonality (seasonal strength SS = 0.771) and notable interannual variation, with a pronounced peak in 2020 (GMT = 1:356), indicating that GMT provides a more sensitive measure of exposure intensity than seropositivity alone. Individual analysis revealed that puppies’ first natural infection after maternal antibodies wane at 3 months of age causes a sharp increase in titer (from negative to 1:2048), serving as a clear signal of active transmission. Adult dogs showed three characteristic patterns of antibody fluctuation—sustained high exposure, recent exposure, and intermittent exposure—reflecting heterogeneous exposure processes. Spatial analysis identified stable hot spots, indicating significant geographic clustering of dog exposure. Application of the moving epidemic method (MEM) further detected periods of elevated transmission intensity in April (GMT = 1:538) and July (GMT = 1:806) of 2020, which corresponded closely with the isolation of Yersinia pestis from marmots in the same year. These findings show that in endemic foci with high seropositivity rates, the dog serum F1 antibody titers, particularly the complementary changes in GMT levels between adults and puppies, serve as a key indicator for assessing plague transmission intensity, identifying increases in epizootic activity, and evaluating spatial spread. This provides a scientific basis for building a more sensitive and proactive plague surveillance system.
Lyu et al. (2026) studied this question.