Abstract
Background
In Sri Lanka, a high seroprevalence of antibodies against hantaviruses was reported in communities affected by chronic kidney disease of unknown etiology (CKDu). Recently, two rodent-borne hantaviruses, Lanka virus and Anjozorobe virus, were identified in these areas. However, it is unclear which virus is the source of infection in humans, and its pathogenicity is unknown.
Methodology/principal findings
A total of 181 sera from febrile patients from two CKDu-endemic regions, Girandurukotte and Polonnaruwa, were examined and Lanka virus genome was detected in two IgM-positive febrile patients. Of 76 serum samples from patients with fever of unknown etiology collected during 2016 examined to identify hantavirus genomes, antibodies, and serotypes, 10 were IgG-positive with five of them having IgM also. They were all without clinical features of hemorrhagic fever with renal syndrome, but three patients required treatment in the intensive care unit. A serotyping strategy was established based on the antigenic difference of the glycoprotein Gn of Lanka and Anjozorobe viruses. Using this method, febrile patients were found to be infected with the Lanka virus and none of the patient sera showed Anjozorobe virus infection pattern. Additionally, a total of 373 previously diagnosed seropositive serum samples from CKDu patients and healthy residents were serotyped to categorize 87% of seropositives as Lanka virus infection.
Conclusions/significance
Lanka virus carried by little Indian field mouse (Mus booduga) is transmitted to humans, likely causing febrile illness occasionally while leading to severe disease in some of the febrile patients.
Author summary
Hantaviruses are known to be transmitted by rodents and cause severe diseases such as hemorrhagic fever with renal syndrome (HFRS) in humans. Although there have been few reports of typical HFRS in Sri Lanka, there are many antibody-positive individuals. The antibody positivity rate is particularly high in patients with chronic kidney disease by unknown etiology (CKDu), and the relationship between hantavirus infection and CKDu is being discussed. Meanwhile, rodent surveys have identified Lanka virus in little Indian field mouse (Mus booduga) and Anjozorobe virus in black rat (Rattus rattus) in Sri Lanka. However, it was unclear which virus was infecting the humans and its pathogenicity. This study showed that hantavirus infections in Sri Lanka could be asymptomatic or cause common fever-like symptoms and rarely require treatment in an ICU. It was also shown that the main source of infection is Lanka virus. This study leads us to the starting line of clarifying the Lanka virus-related health risks, such as its association with CKDu.
Source: PLoS Neglected Tropical Diseases, https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0013169
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