Hantavirus in rodents of Buenos Aires Province: are seroprevalence and abundance related?

GOROSITO, I.L; BELLOMO, C; MARTINEZ, PV; BUSCH M

La Plata

Congreso; LA SOVE 2022; 2022

Society of vector ecology

Oligoryzomys flavescens and Akodon azarae are two rodent species living inagroecosystems of the Pampean region. O. flavescens is a reservoir of the Lechiguanasgenotype, associated with Hantavirus Pulmonary Syndrome, whereas Akodon azarae is areservoir of the Pergamino genotype, which has not been associated with human cases. Ourobjective was to evaluate whether there is a relationship between abundance andseroprevalence in both rodent species, as this may help to identify situations of high risk ofexposure to hantavirus for humans. Eleven longitudinal rodent capture-mark-recapturesurveys were conducted in three railway embankments in agricultural landscapes (Exaltaciónde la Cruz Departament, Buenos Aires province, Argentina), from 2014 through 2016. Thetrapping effort was 1800 trap-nights per survey. During these surveys, demographic data andblood samples were collected. Blood samples were analyzed by means of ELISAs todetermine the presence of hantavirus-specific antibodies. For each rodent species, therelationship between seroprevalence and its abundance was assessed through logit-linkedbinomial generalized linear models using the number of infected individuals by samplingsession as the response variable (i.e., successees, with the corresponding number of testedblood samples per group as trials). Models containing the species’ MNA as a predictor andthe null models were evaluated. Using a multi-model approach, averaged parameters andtheir relative importance were calculated using Akaike weights (AIC). The main finding in thiswork was that both A. azarae and O. flavescens exhibit a negative relationship betweenprevalence and abundance. A possible explanation for this result is that populations reachtheir smaller numbers when these consist mainly of overwintering adults, which had longerexposures with higher chances of becoming infected, whereas larger populations areobserved soon after the reproductive season, when new recruits are unlikely to be infectedyet. Thus, the effect of prevalence and abundance on the risk of human exposure could becompensatory. This suggests that there would be no particular season of increased risk;prevention and surveillance should be permanent.