The Hantavirus genus comprises rodent borne, zoonotic viruses of the Bunyaviridae family that cause
hemorrhagic fever with renal syndrome (
HFRS) in Eurasia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. Rodent saliva contains infectious hantavirus and evidence suggests that hantavirus is also shed in human saliva, but person-to-person transmission is rare. In saliva,
immunoglobulin (Ig) A is the predominant
immunoglobulin class.
Secretory IgA serves as an important first line of defence on epithelial surfaces and the binding of
secretory IgA to pathogens can inhibit adherence of microorganisms to mucosal cells and neutralize viruses. This study investigated the presence and importance of salivary
IgA in relation to
viral antigen in the saliva by testing Puumala hantavirus (PUUV) specific
IgA, and
RNA in saliva in acutely ill patients with
HFRS. In saliva samples, PUUV specific
IgA was detected in 12 of 33 (36%) patients with
HFRS and 20 (61%) were PUUV
RNA positive. There was a statistically significant inverse association between the presence of salivary
IgA antibodies and PUUV
RNA in the saliva. PUUV-specific
IgA in saliva was not found in a long-term follow-up, while PUUV
IgA in serum was detected in three patients, 28-32 months after the initial study. Notably, both PUUV
RNA and PUUV nucleocapsid
antigen were detected in endothelial cells within the parotid gland of a deceased patient with
HFRS.