Following is a question by the Hon Chan Pok-chi and a written reply by the Secretary for Health, Professor Lo Chung-mau, in the Legislative Council today (June 3):

Question:

     According to reports, a recent study published in the prestigious international journal Nature Microbiology suggests that covert mortality nodavirus (nodavirus), which was previously only found in aquatic animals, is suspected of being capable of cross-species transmission to humans. It is also linked to a sight-threatening eye disease. The World Organisation for Animal Health has classified the virus as an emerging communicable disease. There are currently about 70 suspected cases of human infection worldwide, with potential modes of transmission including consuming undercooked seafood and sustaining puncture wounds while handling raw and fresh aquatic products with bare hands. In this connection, will the Government inform this Council:

(1) whether targeted testing for nodavirus was carried out in the routine testing of imported raw and fresh aquatic products (particularly shrimp products) conducted by the Food and Environmental Hygiene Department over the past year; if so, of the number of samples tested, the origins of the products, and the number of positive results; if not, the reasons for that;

(2) whether the Department of Health (DH) has recorded the number of local cases of people seeking medical treatment for unexplained eye diseases (including anterior uveitis, ocular hypertension and vision loss, etc.) in the past year following the handling or consumption of aquatic products; if so, of a breakdown by age group and history of exposure to aquatic products; whether the Government has estimated the number of workers who frequently handle raw and fresh aquatic products with their bare hands, in order to assess the population at risk of nodavirus exposure;

(3) given that Hong Kong is a major importer of raw and fresh aquatic products, will DH consider including nodavirus on the list of statutorily notifiable communicable diseases and require doctors to report suspected cases; if not, the reasons for that; as it is learnt that other regions have already issued public guidance on precautions against this virus, whether DH will draw on such practices to establish a mechanism for submitting samples for testing; if not, the reasons for that; and

(4) whether the Government will collaborate with the Hospital Authority, the seafood trade, and the Consumer Council to launch public education campaigns in the near future to remind high-risk individuals (such as people with compromised immune systems) to wear protective gloves when handling raw and fresh aquatic products; if not, the reasons for that?

Reply:

President,

     Covert Mortality Nodavirus (CMNV) primarily infects aquatic animals and is prevalent in farmed and wild aquatic animals worldwide. In March 2023, the World Organization for Animal Health listed CMNV infection as an emerging aquatic disease to highlight its impact on global aquaculture. In response to the Hon Chan Pok-chi's question, the reply after consultation with the Environment and Ecology Bureau (EEB) and the Department of Health (DH) is as follows:

(1) The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department implements the Food Surveillance Programme to collect food samples under a risk-based principle for conducting suitable tests on an ongoing basis. Over the past year (2025), the CFS tested more than 8 000 samples of aquatic and related products (including around 940 samples of shrimp and their products), which are mainly imported from the Mainland, Thailand, Japan, Vietnam, and France.

(2) The Centre for Health Protection (CHP) of the DH has noted a recent study reporting suspected human cases of persistent ocular hypertension viral anterior uveitis (POH-VAU) associated with CMNV infection, with improper handling of aquatic animals and consumption of raw aquatic animals being the main routes of infection in the studied cases. However, CMNV is a virus that mainly affects aquatic animals, and the rare human infected cases reported in the study still require further research to confirm its transmission routes and related high-risk groups. At present, the CHP does not keep records of the number of cases seeking medical attention for unexplained eye diseases after handling or consuming raw aquatic products. To date, no confirmed CMNV human case has been recorded by the CHP locally, and there have been also no reports of such cases from the World Health Organization (WHO) or other overseas health authorities.

     Regarding the number of workers who frequently handle raw and fresh aquatic products with their bare hands, the EEB does not keep records of such figures.

(3) to (4) Hong Kong has long maintained comprehensive communicable disease surveillance systems, including surveillance of statutory notifiable infectious diseases, sentinel surveillance, outbreak surveillance, and laboratory surveillance. These systems closely monitor the activity of various communicable diseases in Hong Kong as well as the latest global situation. 

     The Government will consider a number of factors in determining whether a particular infectious disease should be statutorily notifiable, such as the prevalence and severity of the disease, risks of local outbreak, existence of a reliable diagnostic method, availability of effective personal or public health intervention and other more effective surveillance methods, surveillance and reporting requirements of the WHO and other overseas health authorities. 

     Currently, the CHP's risk assessment indicates that the impact of CMNV infection on local public health is extremely low, and there are no plans to list it as a statutorily notifiable infectious disease at moment.

     The CHP will continue to closely monitor the latest developments of CMNV, as well as the latest recommendations from the WHO and other overseas health authorities, and will take appropriate follow-up measures based on risk assessments, including developing guidelines and strengthening public health education, to safeguard public health and the health of the public.

Ends/Wednesday, June 3, 2026
Issued at HKT 15:00

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