Hematological Characterization of Common Bats in Urban Areas from Mérida (Venezuela), and Observations on Possible Hemopathogens

Bats are the second most diverse and widely distributed group of mammals, and may be directly or indirectly involved in some zoonotic diseases. Their baseline hematological knowledge and health condition in natural populations are important parameters, but when bats and humans cohabitate common spaces such as houses, buildings, and recreational parks, these variables become essential. Blood samples of bats representing 16 species from families Phyllostomidae (nine species; n = 104 individuals), Noctilionidae (two species; n = 24), and Molossidae (five species; n = 9) were obtained from 137 individuals captured in human-related spaces mostly in Merida state, Venezuela. Hematocrit (Hct), total white blood cell counts (WBC), and differential white blood cell counts (DWBC) were quantified, and profiles compared in groups with large samples sizes and unambiguous reproductive conditions. Also, a general examination of blood smears was performed to assess the viability of in situ hemopathogen identification. Hct (x ± SEM) of bats was 51.0 ± 1.9% for Artibeus lituratus (n = 53) and 51.0 ± 3.8% for A. jamaicensis (n = 18), the two most common bat species captured. WBC were higher in Phyllostomidae than in the other two families, and most species exhibited a DWBC formula dominated by lymphocytes. Lactating and pregnant females of A. lituratus showed higher values of neutrophiles than males and non-reproductive females. Overall, blood cell morphology and hematological profiles were consistent with those of other species of bats and/or mammals. Hemopathogens were observed in 19 individuals from three species. In this study, we report Anaplasma-compliant observations in blood samples of bats, but this first report requires molecular validation and further research to expand the knowledge on hemopathogens of bats. Our research is an important contribution to the hematological characterization of common species of Neotropical bats, and the first in providing hematological data for six species from three families of bats.