Dinâmica da raiva em diferentes espécies animais no Ceará: um estudo com ênfase em morcegos

Abstract

Rabies is a neglected viral zoonosis with a lethality rate close to 100% and significant economic impacts. This study analyzed the spatial and temporal distribution of animal rabies in Ceará between 2003 and 2023, focusing on bat positivity from 2014 to 2023 and its relationship with environmental and sociodemographic factors. Data were obtained from the Ceará Health Department and the Ceará Agricultural Defense Agency, along with information from IBGE and IPECE. Due to the relevance of bats in the transmission cycle, an in-depth investigation was conducted on these animals between 2014 and 2023.Temporal trend analysis applied segmented linear regression using Joinpoint software version 4.6, while spatial analysis utilized QGIS 3.34.3 and SaTScan for cluster identification. The correlation between environmental and sociodemographic variables was determined using Spearman’s coefficient, with a 95% statistical significance. A total of 19,249 samples were analyzed, of which 1,377 (7.25%) tested positive for animal rabies, with an annual average of 65.6 cases.In dogs, a significant decline was observed between 2003 and 2005 (APC=-69.3%; 95% CI -78.6 to -50.08; p<0.001), followed by stability. In cats, positivity fluctuated with a slight increase (APC=7.58%; 95% CI 1.44 to 13.25; p=0.02). Among wild animals, bats accounted for the highest proportion of cases (499; 60.5%), with continuous growth in positivity (APC=8.78%; 95% CI 4.48 to 17.72; p=0.03) and a peak in 2019. Herbivores also showed a significant increase between 2003 and 2019 (APC=6.42%; 95% CI 3.04 to 13.89; p=0.01), followed by a sharp decline between 2019 and 2023 (APC=-42.05%; 95% CI -76.38 to -22.97; p=0.005).Spatial analysis indicated a higher concentration of cases in the eastern (408; 29.6%) and northwestern (359; 26.07%) regions. Bats predominated in the eastern part of the state (324; 64.9%), while herbivores were more affected in the south (97; 23.4%) and central-south (75; 18.1%). Among the 3,202 bat samples, the average positivity rate was 14.4%, with peaks in 2019 (22.6%) and 2020 (29.3%). Most samples came from non-hematophagous bats (98.7%), but hematophagous bats had a higher positivity rate (17%). Urban areas had a higher concentration of positive cases (62.5%), suggesting greater human exposure. Spatial analysis revealed significant clusters in southern Ceará (RR=10.93; p<0.001) and the east (RR=1.77; p=0.027) between 2014 and 2018, with expansion in the east between 2019 and 2023 (RR=1.66; p=0.001). Sociodemographic correlation showed a positive association with the Human Development Index (HDI-M) (rho=0.35; p<0.001) and population density (rho=0.26; p<0.001), while the Social Vulnerability Index had a moderate negative correlation (rho=-0.26; p<0.001). The THEIL index and altitude also showed weak negative correlations (rho=-0.18; rho=-0.19), both significant. The seasonality of positivity, the rise in bat cases, and their association with environmental factors reinforce the need for integrated actions within the "One Health" framework to mitigate risks in vulnerable areas.