Spatial epidemiology of Leptospira sp. exposure in bovines from
Veracruz, México
Abstract
Bovine leptospirosis is a bacterial disease that affects cattle herds,
causing economic losses due to reproductive problems, which require
expensive treatments. The main source of transmission for cattle is
still uncertain, but it has been described that rodents and bats can
play an important role in the transmission cycle by being maintenance
hosts for the pathogenic species of the bacterium and spreading it
through urine. In this study, we characterize possible risk areas for
bovine leptospirosis exposure in the state of Veracruz, Mexico, based on
the geographical distribution of flying (bats) and terrestrial (rodents
and opossums) wild hosts of Leptospira sp. reported in Mexico in
addition with climatic, geographic, soil characteristics, land use and
human activities variables (environmental variables). We used a
generalized linear regression model (GLM) to understand the association
between the frequency of anti- Leptospira sp. antibodies (a proxy
of exposure to) in cattle herds exposed to Leptospira, the
favorability of wild hosts of Leptospira as well as the
environmental variables. The parameterized model explains 12.3% of the
variance. The frequency of anti- Leptospira sp. antibodies
exposoure in cattle herds was associated with elevation, geographic
longitude, pH of the soil surface and environmental favorability for the
presence of rodents, opossums, and bats. The variation in exposure is
mainly explained by a longitudinal gradient (6.4% of the variance) and
the favorability-based indices for wild hosts (9.6 % of the variance).
Describing the possible risks for exposure to Leptospira in an
important and neglected livestock geographical region, we provide
valuable information to the selection of areas for diagnosis and
prevention of this relevant disease.