Human serological reactivity for Hantavirus in the North of Spain

Abstract

Introduction: Spain is an extensive country where several species of rodents can befound, all distributed geographically according to diverse ecological characteristics.While rodents ofthe species Rattus norvegicus, Apodemus sylvaticus and Mus musculusare widely extended, others such as Clethrionomys glareolus, the main reservoir forPuumala virus ín Europe, have only been described in the Autonomous Cornmunitiesplaced in the north half of Spain. In this study we researched the seroprevalence of Hantavirus infection in the Autonomous Communities where C. glareolus has been described and we analyzed the pattems of serological reactivity in the positive sera.Material And Methods: A total of 3627 sera were collected from different hospitals ofProvinces belonging to seven of the nine Autonomous Communities placed in the northhalf of Spain: 992 from Galicia, 350 from Asturias, 200 from the País Vasco, 100 fromNavarra, 200 from Aragón, 219 from Cataluña and 1566 from Castilla y León.The sera were analysed by indirect fluorescence inmmunoassay using as antigens VeroE6 cells 50% infected with the virus Seoul (strain 80/39-SEOV), Hantaan (strain76/118- HTNV) and Puumala (strain Hallnas-B 1- PUUV)- All those sera that weredoubtful or posítive to an initial 1/16 dilution were titrated. Sera having a titre ofantibodies >_ 1/32 were considered positive. Results: A total of 59 positive sera were found. Toe global seroprevalence was 1.6% (from 0% for Aragón to 3.5% for the País Vasco). Toe antibody titres ranged from l/32 to 1/1024. Regarding to the sex, 26 were females and 33 males, not establishing differences statistically significant (1,3% females vs 1,5% males). Toe mean age of the seropositives was 41 years (from 2 to 86 years). 81% ofthe positive sera reacted for PUUV, 58% did for HTNV and 39% for SEOV. More than half of the positive será showed two reactivity pattems: PUUV-HTNV (33,9%) and PUlN (23 .7%)-Discussion and Conclusions: In all the studied Communities the existence of C.g/areolus has been previously demonstrated, although the regions of Aragón, Cataluñaand Galicia Comunities included in this work, do not correnpond exactly with thegeographical distribution of this rodent. Except for Aragón, positive sera have beenfound in all these Communities.With the exception of Asturias, where a Seoul-like strain seems to be the mostimportant Hantavirus, PUUV resulted the most reactive, in a single way or ínconjunction with other strains. Toe reactivity pattem HTNV-PUUV is even the mostfrequent in the areas where this rodent has not been described, and it could beconsidered an Hantavirus strain wich differs :from those described until the moment.Previous studies carried out with severa! species of rodents from Soria (Castilla y León)support these results. However no Spanish strain of Hantavirus has been isolated yet,remaining unknown the corresponding reservoir. It is important to adress the studies inthis sense and to clarify the possible role our strains could be playing as pathogens inhumans. (Resumen completo publicado en: Emergence and Control of Rodent-Borne Viral Diseases (Hantaviral and Arenal Diseases). Symposium 'Emerging Diseases' , Elsevier, 1998. ISBN 978-28-4299-114-2)