File photo of the Nipah virus disease. Photo: VCG

The Chinese National Disease Control and Prevention Administration on Tuesday said no cases of Nipah virus disease have been detected in China, noting that the current Nipah outbreak in India is mainly occurring in West Bengal, which does not share a land border with China. 

The administration said that the Nipah virus is primarily transmitted through direct contact with infected animals, patients, or contaminated objects. The virus has weak environmental survivability, so the general public has a relatively low risk of infection through contact. 

"Based on a comprehensive assessment, the impact of this Nipah virus outbreak in India on China is relatively small," the administration said, while adding that there is still a certain risk of importation from abroad, and prevention measures need to be strengthened.

People traveling to countries with Nipah virus outbreaks should enhance disease prevention awareness, maintain good personal hygiene, pay attention to food safety, avoid contact with bats, livestock, and other animals, avoid contact with patients or secretions and excretions from infected animals, avoid eating fruits, vegetables, and products of unknown origin, and must not eat raw or drink untreated fresh foods and beverages, according to the administration. 

After this outbreak of Nipah virus disease in India, China's disease control authorities promptly took action, closely monitored overseas epidemic developments, and conducted timely risk assessments. The authorities further carried out training for medical and disease control professionals, strengthened surveillance and testing, and particularly enhanced response and handling capabilities in border areas to guard against potential risks, according to the administration. 

The World Health Organization (WHO) exclusively told the Global Times on Tuesday in an email reply that it considers the risk of further spread of Nipah infection from the Indian cases to be low, adding that there is no evidence yet of increased human-to-human transmission.

However, the WHO official said the source of infection is not yet fully understood. 

Chinese experts told the Global Times that the Nipah virus has a strong capacity for recurrent outbreaks and a high fatality rate. Previous cases have shown that human-to-human transmission of the Nipah virus primarily occurs through hospital-acquired infections, and infections resulting from a single spillover event may only be limited to small-scale isolated outbreaks.

Asian airports including China's Hong Kong Special Administrative Region and Taiwan region, as well as Thailand and Nepal have tightened health surveillance and passenger screening following the recent Nipah virus outbreak. 

Hong Kong SAR's Department of Health said on Monday that it is conducting health screenings on inbound travelers from the affected area who exhibit suspected symptoms. Currently, there are no imported or local cases of Nipah virus infection in Hong Kong, per a SAR government release. 

Health authorities in China's Taiwan region also said they had released a proposed change to measures on controlling infectious diseases and intend to list Nipah virus infection as a Category 5 notifiable disease following the recent outbreak in India.

The Tourism Authority of Thailand (TAT) said on Tuesday that no cases of Nipah virus infection have been found in Thailand so far, and there is no evidence of local transmission. "The public health situation in Thailand remains stable and the country will continuously carry out preventive measures such as routine disease surveillance and health screening as well as monitoring the situation in India."

Per media reports on Monday, Indian health authorities have confirmed two cases of Nipah virus infection among nurses at a private hospital near Kolkata, West Bengal, with one of them in critical condition. Health officials believe the infections may be linked to a patient who was previously admitted to the same hospital with severe respiratory symptoms and died before testing for Nipah could be conducted. 

According to the World Health Organization, Nipah virus infection is a zoonotic illness that is transmitted to people from animals, and can also be transmitted through contaminated food or directly from person-to-person. 

The case fatality rate is estimated at 40 to 75 percent, with no approved treatment or vaccine available for either people or animals, and the primary treatment for humans is supportive care, the WHO website shows. 

The WHO said there is "an urgent need" for accelerated research and development for the Nipah virus. 

The WHO has not responded to Global Times inquiries regarding the recent outbreak as of press time. 

Lu Hongzhou, head of the Third People's Hospital of Shenzhen, who has previously conducted research on the Nipah virus, noted that the virus has a strong capacity for recurrent outbreaks and has a high fatality rate. The virus primarily targets the respiratory system and central nervous system, leading to acute fever, headache, and varying degrees of altered consciousness, with disease symptoms and signs typically appearing 3 to 14 days after exposure. 

Public reports indicate that the Nipah virus first emerged in an outbreak in Malaysia in 1998, and has since caused multiple outbreaks in South Asia, Southeast Asia, and other regions. Previously, India experienced its first Nipah virus outbreak in 2001, with 66 suspected cases and 45 deaths. Since then, the virus has caused repeated outbreaks, all of which have resulted in fatalities.

Lu added that while strong evidence confirms fruit bats as the natural reservoir of the Nipah virus, increasing evidence shows the virus is rapidly adapting to other hosts with different transmission modes. 

"Although infections resulting from a single spillover event may be limited to small-scale isolated outbreaks, the repeated spillover of a pathogen could lead to larger-scale outbreaks. Accelerating the development of specific antiviral drugs and vaccines is a key strategy for future epidemic prevention and control," Lu noted.

A joint research by Chinese scientists has recently found that the oral nucleoside drug VV116, approved for the treatment of COVID-19, shows significant antiviral activity against the Nipah virus, bringing new hope for the prevention and treatment of this emerging fatal infectious disease, according to a statement released on Monday by the Wuhan Institute of Virology under the Chinese Academy of Sciences (CAS).