Background
Nipah virus infection is a zoonotic disease that can be transmitted from animals to humans, and it may also spread through contaminated food or close human contacts. According to World Health Organization (WHO) data, the incubation period ranges from 3 to 14 days with a case fatality rate of 40% to 75%. Clinical manifestations of Nipah virus infection vary widely, from asymptomatic infection to acute respiratory disease or fatal encephalitis. Initial symptoms (approximately 3 to 14 days after onset) often include non-specific symptoms such as fever, headache, myalgia, vomiting, and sore throat, which may subsequently progress to dizziness, drowsiness, altered consciousness, and other neurological signs of acute encephalitis. Some people may experience atypical pneumonia or acute respiratory distress. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours. Currently no licensed treatment or vaccine is available for Nipah virus infection. Primary treatment is symptomatic and supportive care.

Epidemiology
Nipah virus was first identified in 1998 during a zoonotic outbreak in Malaysia and Singapore. Epidemiological investigations revealed that fruit bats (Pteropus genus) transmitted the virus to pigs, which subsequently infected farmers and slaughterhouse workers in close contact with infected pigs. Human cases have reported in Bangladesh and India since 2001, with some linked to consuming raw date palm sap, and some involving nosocomial transmission. The Philippines experienced an outbreak of equine-to-human transmission in 2014. Recent cases have mainly occurred in Bangladesh and India. So far, no confirmed case has been reported in Taiwan.

Nipah Surveillance in Taiwan
1. Taiwan National Infectious Disease Statistics System-Nipah Virus Infection(Category 5 Communicable Disease)
2. Fever screening at international airports and seaports.
3. Self–reporting through the toll–free 1922 hotline or local public health authority.
4. Acute encephalitis of unknown etiology

Prevention and Control
1. Travelers to affected areas should maintain good personal hygiene practices, avoid contact with bats and pigs—particularly sick or dead animals—and refrain from entering bat roosts or touching environments or items potentially contaminated by bat excrement. Avoid consuming raw date palm sap or eating fallen fruits; thoroughly wash and peel fruits before consumption.
2. During travel or upon return, if symptoms such as fever, cough, shortness of breath, or altered mental status develop, travelers should proactively report to quarantine officers at the point of entry for health assessment and quarantine measures. If symptoms arise after returning home, individuals are advised to wear a mask, seek medical attention immediately, and inform healthcare providers of recent travel and exposure history to facilitate timely diagnosis and public health reporting.
3. Contact with animals requires appropriate personal protective equipment (PPE), such as gloves, masks, and protective clothing, especially when handling sick animals or their tissues; wash hands with soap or other exposed areas thoroughly after contact.

FAQs
Q1. What are the sources of Nipah virus?
A: The natural reservoirs of the Nipah virus are fruit bats of the family Pteropodidae, specifically those within the genus Pteropus. While these bats can carry the virus long-term without manifesting clinical symptoms, they shed the virus through their saliva, urine, or feces, thereby contaminating the environment and food sources. Furthermore, the Nipah virus can infect a variety of intermediate hosts, including pigs, horses, goats, dogs, and cats, which can subsequently facilitate transmission to humans.

Q2. How is Nipah virus transmitted to humans?
A: Transmission of the Nipah virus primarily occurs through three routes: zoonotic (animal-to-human), contaminated food, and human-to-human transmission:
1. Animal-to-Human Transmission: The virus can be transmitted to humans from fruit bats (Pteropus genus) and pigs. Human infections most commonly occur through direct contact with infected pigs or exposure to their respiratory droplets, nasal and oral secretions, or contaminated tissues.
2. Contaminated Food Transmission: Consumption of fruits or raw date palm sap contaminated with the urine or saliva of infected fruit bats can lead to infection.
3. Limited Human-to-Human Transmission: Family members, caregivers, community contacts, and healthcare workers may become infected through close contact with the bodily fluids, secretions, or excretions of an infected patient.

Q3. What are the treatments?
A: Currently there is no licensed treatment or antiviral drug for Nipah virus infection. The primary treatment is symptomatic and supportive care.

Q4. Are there vaccines available for Nipah virus infection?
A: Currently, there are no vaccines approved for human use against Nipah virus.

Q5. How can Nipah virus infection be prevented?
A:
1. Travelers to affected areas should maintain good personal hygiene practices, avoid contact with bats and pigs—particularly sick or dead animals—and refrain from entering bat roosts or touching environments or items potentially contaminated by bat excrement. Avoid consuming raw date palm sap or eating fallen fruits; thoroughly wash and peel fruits before consumption.
2. During travel or upon return, if symptoms such as fever, cough, shortness of breath, or altered mental status develop, travelers should proactively report to quarantine officers at the point of entry for health assessment and quarantine measures. If symptoms arise after returning home, individuals are advised to wear a mask, seek medical attention immediately, and inform healthcare providers of recent travel and exposure history to facilitate timely diagnosis and public health reporting.

More information
WHO/Nipah Virus Infection
USA CDC/ Nipah Virus Infection(NiV Infection)