Serological profiling of hantavirus infections in chronic kidney disease of unknown etiology non-endemic regions of Sri Lanka.

High seropositivity (40-60%) to hantaviruses among patients with chronic kidney disease of unknown etiology (CKDu) and relatively lower seropositivity (15-20%) among healthy individuals in CKDu endemic areas of Sri Lanka was reported, suggesting a possible link between hantavirus exposure and CKDu. However, only a few studies have been conducted in CKDu non-endemic areas. A recent study revealed the presence of two Thailand orthohantavirus (THAIV)-related viruses, Lanka virus (LNKV) and Anjozorobe virus (ANJZV) in Sri Lanka. This study was conducted in three districts that are predominantly CKDu non-endemic (Kurunegala, Matale, and Kegalle) to assess hantavirus seropositivity in the community. A total of 760 human sera were collected from 2021 to 2022. Of the 760 samples, 486 were from community controls and 274 were from renal patients. Serum samples were tested using an indirect immunofluorescent antibody assay (IFA) based on both THAIV authentic antigens and recombinant N antigen. Positive sera were further tested with LNKV recombinant glycoprotein (rGP) and serotyped with LNKV and ANJZV recombinant Gn antigens. Seropositivity among the community participants of Kegalle, Kurunegala, and Matale districts was 8.6%, 10.5%, and 6.4%, respectively, while among renal patients, the rates were 4.3%, 17.2%, and 10%, respectively. Although no significant difference was observed between the community controls and renal patients, significantly higher seroprevalence in males (12.4%) than in females (5.9%) was observed. Of the 45 seropositive sera to rGP, 21 were serotyped as LNKV infection, and 2 were serotyped as ANJZV infection. A total seropositivity in community controls in this study (8.8%) was lower than previously reported. These observations suggest that LNKV exposure occurs in CKDu non-endemic areas, but at a lower frequency than in CKDu endemic areas.