Molecular evidence of hantavirus infection among clinically suspected patients with hae-morrhagic fever with renal syndrome (HFRS)

Abstract

INTRODUCTION: Hantavirus disease is an emerging zoonotic viral infection with high fatality. Transmission is by inhalation of aerosols generated from virus contaminated rodent excreta. There are two major clinical forms, haemorraghic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Clinical features of HFRS, often mimic leptospirosis. Large number of cases of leptospirosis like illness has been reported in Sri Lanka annually. Although there were serological evidence of different types of hantavirus infection in Sri Lanka, diagnosis of hantavirus is not routinely performed. Due to the genetic and antigenic diversity, an assay that could detect a wide range of hantaviruses need to be established. OBJECTIVES: To establish, evaluate and validate a genus specific hantavirus RT-PCR assay. To diagnose hantavirus infection among clinically suspected HFRS patients in three selected hospitals.To describe clinical manifestations of hantavirus infections in the study population. METHODOLOGY: Genus specific conventional RT-PCR assay was established using panhanta primers and evaluated, optimized and validated using synthetic genes of 12 known hantavirus species as reference samples. Assay was able to detect a wide range of hantaviruses at minimum detection limit of 70 copies/ reaction. Molecular diagnosis of hantavirus infection was carried out in three hospitals in Colombo and Gampaha districts. Study was conducted from 01st of January 2011 to 31st of April 2011 and 61 adult patients were recruited to this study. Hantavirus RT-PCR was performed on all collected samples after extraction of RNA by TRIzol® method. RESULTS: Of 61 tested samples, 05 were positive for hantavirus genome. These results were confirmed at reference laboratory as well and species identification result is pending. Of 58 tested samples, 06 samples were positive for hantavirus IgM by in-house ELISA. All PCR positive samples were positive for hanta virus IgM. All patients with hantavirus infection had clinical and biochemical features of liver involvement in addition to fever, thrombocytopenia and renal involvement. CONCLUSION: Established RT-PCR assay was able to detect a wide range of hantaviruses and by using it molecular evidence of hantavirus infection was demonstrated in humans in Sri Lanka. Further studies are required to describe the disease epidemiology and to identify natural hosts in the country.