The Centers for Disease Control (hereafter referred to as the CDC) announced today (the 27th) that, considering the ongoing outbreaks of Nipah virus infection internationally and assessing its fatality rate, incidence, and transmission speed and other risk factors, in order to protect public health and reduce disease threats, it has announced since January 16 that “Nipah Virus Infection” will be classified as a Category 5 statutory infectious disease, to strengthen system early warning, raise public awareness of epidemic prevention, swiftly mobilize resources, and appropriately respond to possible future outbreaks.
The CDC explained that Nipah virus infection is a zoonotic disease, with its natural reservoir being fruit bats (genus Pteropus), and it can infect intermediate hosts such as pigs, which then transmit it to humans. Transmission routes are mainly divided into animal‑to‑human, food‑borne, and limited human‑to‑human categories, including direct contact with infected pigs, consumption of food contaminated with fruit bat urine or saliva, or infection through close contact with a patient’s blood, bodily fluids, or respiratory secretions. Clinical manifestations are broad, ranging from asymptomatic infection and acute respiratory symptoms to fatal encephalitis.
CDC surveillance data show that Nipah virus was first identified in a human case in Malaysia in 1998, with an outbreak also occurring in Singapore the following year. In recent years, cases have mainly occurred in Bangladesh and India. The Bangladesh outbreak is seasonal, usually occurring from December to May, and is associated with fruit bat activity and exposure factors such as drinking fresh date‑palm sap. However, after the first detection of a case on the southern island of Pora in August last year, the outbreak has shown a trend toward year‑round transmission and nationwide spread; of the country’s 64 districts, more than 35 have recorded cases. In India, the outbreak was initially concentrated in the southern state of Kerala, with infections largely stemming from contact with contaminated fruit or from nosocomial (hospital‑acquired) human‑to‑human transmission, and cases have mainly been small‑scale community clusters rather than sustained large‑scale epidemics. A recent outbreak occurred in West Bengal in the east, with a cumulative report of five confirmed cases as of January 25, two of which were severe. There is currently no approved treatment or vaccine; WHO data indicate a case‑fatality rate of approximately 40%–75%, and the World Health Organization assesses that Bangladesh, India, and neighboring regions still face ongoing risk, although the global risk remains low.
The CDC noted that countries that have already listed Nipah virus infection as a statutory infectious disease include Japan, Singapore, South Korea, Thailand, and India. After completing the notification procedure, Taiwan is expected to formally classify it as a Category 5 statutory infectious disease in mid‑March. Physicians who identify a suspected case meeting the reporting definition should report it within 24 hours through the Notifiable Infectious Diseases Reporting System (NIDRS) and submit specimens for testing, and the patient should be placed in a designated isolation and treatment facility for isolation therapy. Healthcare personnel caring for suspected or confirmed Nipah virus patients are advised to follow medical care protocols and implement standard precautions as well as contact, droplet, and airborne infection control measures.
Since 2000, the CDC has established Nipah virus testing capability and, together with the Ministry of Agriculture, conducts surveillance through multiple channels. “Nipah virus encephalitis” has been classified as a Category B animal disease by the Council of Agriculture (now the Ministry of Agriculture) since 2012, and the CDC has listed Nipah virus infection as a “key surveillance item” since 2018 to strengthen case monitoring; to date, no domestic human or animal cases have been confirmed. The CDC issued a circular to the medical community today, reminding physicians to inquire about travel history. During the statutory infectious disease notification period, if a hospitalized patient has a travel history to Nipah‑endemic areas (Bangladesh, Kerala in India, or West Bengal) and presents with fever, seizures, abnormal brain imaging, or other neurological signs, combined with encephalopathy (altered consciousness ≥24 hours or personality change) or ataxia, and after excluding other viral encephalitis diagnoses, the case may be reported under the “key surveillance items” in the NIDRS as “Nipah virus infection” and specimens should be collected for testing.
The CDC reminds the public that, to reduce the risk of infection, people should avoid traveling to Nipah‑endemic areas. If travel to affected regions is necessary, maintain good personal hygiene, avoid contact with bats and pigs, and avoid environments or objects that may be contaminated by bats, as well as refrain from drinking fresh date‑palm sap and consuming contaminated fruit. For more information, visit the CDC’s global website Nipah Virus Infection section (https://gov.tw/BF4) or call the domestic toll‑free epidemic prevention hotline 1922 (or 0800‑001922).
Source: Centers for Disease Control
Compiled by: Surveillance Division
