A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Nipah virus causes outbreaks in humans with high case-fatality rates. In this study, we confirmed the presence of Nipah virus in Sri Lanka in Pteropus medius fruit bats, one of the known natural reservoir species. Sequences we generated were genetically related to Nipah virus strains from outbreaks in southern India.
Nipah virus (NiV; Henipavirus nipahense ) and Hendra virus ( H. hendraense ) are species within the genus Henipavirus of the family Paramyxoviridae ( 1 ). Several paramyxoviruses, including measles virus and respiratory syncytial virus, cause serious respiratory illnesses and are often highly transmissible through the air. NiV can cause severe outbreaks in humans; its clinical symptoms range from subclinical infection to severe encephalitis, respiratory diseases, and death ( 2 ). Reported case-fatality rate (CFR) of NiV encephalitis is 61% (95% CI 45.7%–75.4%) ( 2 , 3 ).
NiV emerged in 1998 in Malaysia and Singapore ( 4 ). Subsequent outbreaks were reported from Bangladesh, the Philippines, and India; they resulted in >643 laboratory-confirmed infections and 380 deaths ( 2 ). Bats (flying foxes, Pteropus spp.) are the known reservoir hosts of NiV ( 5 ). Transmission from bat to human occurs via exposure to urine, either through consumption of raw palm sap contaminated with bat excreta, direct contact with infected intermediate hosts (e.g., swine), or direct contact with bat urine ( 5 ). In 2023 several cases of Nipah virus were reported from Kozhikode, Kerala district, India, and in Dhaka, Rajbari, and Shariatpur districts in Bangladesh ( 6 ). The shortest distance between Mannar Island, Sri Lanka, and Natarajapuram, India, is <55 km; Pteropus spp. bats are reported to migrate >450 km with ease ( 7 ). In this study, we monitored urine excreted by several colonies of P. medius bats in Sri Lanka for the presence of viruses using molecular techniques. Our focus was to investigate if NiV is present in Sri Lanka and to determine the measures required to prevent spillover into humans. We obtained ethics approval for this study from the Institute of Biology, Sri Lanka (WL/3/2/05/18) and necessary clearance from the Department of Wildlife Conservation, Sri Lanka.
During March 2018–June 2019, we monitored P. medius bat colonies for shedding of pathogens in Colombo, Mannar, Anuradhapura, and Badulla, Sri Lanka. We laid clean sampling sheets below roosting trees in the early morning and transferred excreted urine drop by drop to sterile microtiter plates in the morning using disposable pipettes. We conducted all work while wearing appropriate personal protective equipment (PPE) as previously described ( 5 ).
We collected a total of 2,218 urine samples and combined them into 32 pools with < 8 urine specimens each. We extracted RNA from the individual pools using the QIAamp Viral RNA Mini Kit (QIAGEN, https://www.qiagen.com ). We performed Nipah virus screening using real-time PCR targeting the phosphoprotein (P) gene, as previously described ( 8 ). As an additional confirmation, we developed a real-time PCR targeting the nucleocapsid protein of the Nipah virus genome ( Table 1 ).
Figure 1 . Positions…