Cumulative incidence and spatial distribution of dogs exposed to Toxoplasma gondii

Abstract

Toxoplasma gondii is one of the most important protozoa parasites worldwide. Although many seroprevalence studies have been performed in domestic and wild species, data on the cumulative incidence and the spatial distribution of T. gondii in animals are extremely scarce. In the present study, dogs from Botucatu municipality, São Paulo state, were followed for one year and their blood samples were collected on three moments: days 1, 180, and 360. The sera were submitted to the immunofluorescence antibody test (IFAT) to detect IgG antibodies to T. gondii. Age and sex were compared with IFAT results through statistical tests. Spatial analysis was used to detect clusters of seropositive dogs. Among the 350 dogs that were seronegative on day 1, 53 became seropositive in subsequent samplings; thus, cumulative incidence was 15.1% exposed dogs/year. Age and sex were not associated with serological results. The spatial analysis revealed that seropositive dogs were distributed in all the studied areas, with a significant cluster in a zone with poor sanitary conditions and low socioeconomic status. T. gondii is frequent and widely distributed in the urban area of Botucatu, and impoverished areas are possibly associated with high levels of environmental contamination by this parasite.

Seroprevalence of Toxoplasma gondii in outdoor dogs and cats in Bangkok, Thailand

“…In Brazil, the same dogs were tested for T. gondii antibodies three times, on days 0, 180 and 365. The seroprevalences were 5.1, 6.5 and 15.1%, respectively, revealing an annual seroconversion rate of 10.1% (Olbera et al, 2020). In Switzerland, serial blood samples from 65 cats were collected with a time separation of at least 3 months and analysed for anti-T. gondii antibodies, but no changes were detected over time (Schreiber et al, 2020).…”