EMERGING CHAMOIS RESPIROVIRUS: SERO-EPIDEMIOLOGICAL SURVEY IN ALPINE CHAMOIS AND DOMESTIC SMALL RUMINANTS

In a globalized world, the threat of emerging pathogens plays an increasing role, especially if their host range is unknown. A novel respirovirus, family Paramyxoviridae, distinct from previously defined species, was recently isolated from alpine chamois (Rupicapra rupicapra rupicapra) in Italy. A retrospective sero-epidemiological survey was carried out to assess how widespread the novel respirovirus infection is in chamois and domestic small ruminants between 2010 and 2015. Sampling was carried out in the north-western Alps, where chamois respirovirus has been detected and livestock share pasture, and in separate control areas, central Italian Alps and Alessandria, for chamois and domestic small ruminants respectively. Sera (201 chamois, 185 sheep, and 237 goats) were tested by virus neutralization test against the chamois respirovirus strain. A sero-prevalence of 34.5% (95% CI 27.1- 42.8) was observed in the chamois population of north-western Alps. On the contrary, no positive results were found in chamois from central Italian Alps and goats from all study areas. A seroprevalence of 13.10% (95% CI 8.81-19.03) and 29.41% (95% CI 13.28-53.13) were found in sheep populations, in the north-western Italian Alps and control area respectively. A possible cross reaction and/or co-circulation of other respiroviruses could be be responsible. We have identified the circulation of a novel respirovirus in chamois population as early as 2010, but it didn’t spread into other regions nearby either in chamois or goat populations. More data are needed to understand the spread among sheep. The present study contributes to the knowledge of respiratory infections in wild ruminants and suggests an epidemiological link between chamois and other animal species.