Serological Survey Of Hantavirus Infection Among Rodents In Hungary

Purpose: Hantaviruses are found worldwide and are known to cause serious human diseases. Natural hosts are rodents, soricomorphs and bats. Three types of hantaviruses are circulating in Hungary, Dobrava, Puumala and Tula which are carried by mice and voles. Dobrava and Puumala viruses cause human disease. In Hungarian forests the dominant species of rodents are yellow necked mouse (Apodemus flavicollis) striped field mouse (Apodemus agrarius) wood mouse (Apodemus sylvaticus) and bank vole (Myodes glareolus) which are natural reservoirs. The aim of the study was to survey the prevalence of hantaviruses among rodent populations and examine the potential correlation between population densities and seroprevalence. Methods & Materials: The rodents were trapped at 13 sampling plots on a 149 ha area in the Mecsek Mountains, Hungary from March to Oktober between 2011 and 2014 using a capture- mark- recapture method. Rodent sera were tested for antibodies against the two most significant hantavirus species in Europe, Dobrava- Belgrade (DOBV) and Puumala (PUUV) viruses by ELISA. Results: Among the 3720 tested sera samples 350 were positive for hantaviruses (DOBV, PUUV). In 2011 the seroprevalence was 14,5% (178/1229), but in 2012 despite of the higher number of rodents it was just 7,4% (122/1638), in 2013 and in 2014 it was about 6%. The seroprevalence was the highest for the Apodemus species in the first two year, then in 2013 and 2014 for the Myodes glareolus. In every year among the hantavirus positive rodents the number of males were higher. Conclusion: Since the seroprevalence in 2012 decreased to half despite of the higher sample size, it may indicate that the number of infected individuals and community size are not directly proportional. Since in the subsequent years we registered great decrease in population size, but the infection rate stagnated throughout, it may indicate a time delay between community size changing and infection rate alteration. In four years the number of Apodemus species which were originally abundant in the area decreased and the population density of Myodes glareolus became higher. Therefore at the last year of the survey of 2014, the Puumala hantavirus seroprevalence was much higher compared to Dobrava seroprevalence.