Serological evidence of Hantavirus disease in Northern Ireland

Since, to our knowledge, no clinically documented cases of haemorrhagic fever with renal syndrome (HFRS) have been reported in Northern Ireland, a sero-epidemiological study was carried out to assess the degree of Hantavirus immunity in a group of 627 Northern Irish patients presenting with symptoms suggestive of HFRS and 100 healthy controls. IFA screening for IgG Hantavirus specific antibodies was carried out with a panel of up to 9 different Hantaviral antigens. IgM screening was performed using a commercially available mu-capture ELISA based upon two recombinant Hantaviral nucleocapsid antigens. A seropositivity of 2.1% (15/727) was recorded, with an almost exclusive reaction against a rat-derived R22VP30 strain of the Seoul serotype. Sole reliance upon non-rat-derived classic screening antigens Hantaan (HTN 76-118) and Puumala (CG 18-20) would have resulted in the detection of only 2/15 (13.3%) of cases in IgG IFA, and 8/14 (57.1%) of the cases in IgG ELISA. The findings indicate that for the first time in Europe, and more specifically in N. Ireland, non-laboratory outbreaks of HFRS may be caused by wild rats acting as a reservoir for a Seoul-like Hantavirus. Conventional Hantavirus serology using Hantaan and Puumala as screening antigens does not appear sufficient for the detection of such cases of HFRS. Hence, we propose the addition of a rat derived Hantaviral antigen to the antigen screening panel as a means of improving the specificity of the detection methods.