In 2013, a novel Orthopoxvirus was described in lesions from two cattle herders from the country of Georgia, prompting multi-year ecological investigations into the status of orthopoxvirues (OPXVs) in this country. Disease dynamics in rodent populations are influenced by a combination of biotic and abiotic factors. The biotic factors reported to have the most influence on viral transmission in a small mammal (rodents and shews) community include factors such as host sex, age, sociality, population densities, and community structure. Given the broad host-range of OPXVs, community level host population dynamics are potentially more pertinent to the epizootiology of OPXV than that of any one species. The purpose of this research was to evaluate the association between community level population dynamics, and variation in the prevalence of OPXV. Small mammals were collected from trapping locations across the country of Georgia. Animals were processed and tested for presence of viral DNA via PCR, and presence of anti-OPXV antibodies via ELISA. Orthopoxvirus prevalence per trapping location was calculated as number of seropositive or PCR positive animals, divided by total captures. We used a multiple linear regression analysis to evaluate the relationship between OPXV prevalence at trap sites and multiple community level population parameters.
Results/Conclusions
A total of 1,446 rodents and shrews were captured from 30 trapping locations across the country of Georgia; morphological and demographic data were recorded for each individual and used in this analysis. In total, 146 rodents and shrews collected were seropositive and/or had PCR positive tissues. Results of the regression analysis yielded positive correlations between higher OPXV prevalence at trap sites with higher proportions of juvenile males (P < 0.01), juvenile females (P < 0.01), non-scrotal males (P < 0.01) and males with wounds (P < 0.01). A negative correlation with higher OPXV prevalence was also observed with adults with signs of breeding activity (P < 0.01). These results may indicate that fluctuations in prevalence of OPXV correlate with certain population dynamics of the small mammal community. Additionally, we observed a positive correlation with wounded males and prevalence of OPXVs, which indicates the virus may be transmitted via behavioral mechanisms such as interactions. These results support the idea that abundance of susceptible hosts and population structure are key parameters in the maintenance of OPXV in Georgian small mammal communities, however further analyses will be conducted to elucidate these preliminary findings.