The influence of parasitism by in the hematological parameters of the white ear opossum () from Campo Grande, Mato Grosso do Sul, Brazil.

Considered ecologically generalist, is reported as reservoir for different species of parasites, especially . However, the knowledge about the influence of on hematological parameters of free-living opossum remains scarce. The present study aimed to evaluate the influence of on hematological parameters of white-ear opossums () from Campo Grande, Mato Grosso do Sul, Brazil. The blood samples and biometric data were collected from 40 opossums captured by Tomahawk and Sherman traps in six urban forest fragments located in the city. The health of these animals was inferred, mainly, by means of blood parameters (PCV, RBC, WBC, MCV and WBC differential). Molecular detection of infection was performed by nested polymerase chain reaction (nPCR), using 18S and 24Sα rDNA region as target. Paired-t-test and simple linear regression were used for statistical analysis. No significant difference was observed between the averages of hematological variables in relation to gender and body condition. The molecular diagnosis showed that 32.5% (13/40) of the opossums were infected by , which presented lymphocytosis (3.4 ± 1.5) and eosinophilia (0.09 ± 0.13). Path analysis showed that infection resulted in increased numbers of lymphocytes and indirectly decreased the body condition of opossums. Moreover infection resulted in a direct effect on decrease of MCV. Overall, our results suggest that infection may represent a risk to health of opossums since the lymphocytosis may cause a secondary damage on body condition of infected animals.