Risk of disease from shrimp low: CDC - Taipei Times

• By Lee I-chia / Staff reporter

The risk of contracting a new type of eye disease by covert mortality nodavirus (CMNV) via exposure to farmed shrimp from China is extremely low in Taiwan, the Centers for Disease Control (CDC) said yesterday, responding to concerns spreading online.

CMNV is listed by the World Organization for Animal Health as an emerging infectious disease, with outbreaks reported in China and Thailand, it said.

The CDC said it has noticed discussions online citing a study published in the scientific journal Nature Microbiology, saying that a virus that typically infects marine animals is suspected of jumping to humans and causing chronic eye disease in some people.

.Photo: Lin Huei-chin, Taipei Times

The study — published last month — they cited is titled "An emerging human eye disease is associated with aquatic virus zoonotic infection," which said that a human ocular disease called persistent ocular hypertensive viral anterior uveitis (POH-VAU) is associated with CMNV of aquatic origin.

The study recruited 70 people diagnosed with POH-VAU in China between January 2022 and April last year for blood testing and interviews and showed that CMNV exposure frequency, number of severe exposures and exposure severity were associated with an increased risk of POH-VAU.

The CDC yesterday said suspected human CMNV infections have only been reported in China, in 18 aquaculture-heavy provinces.

Major international public health organizations, including the WHO, the US CDC and the European Centre for Disease Prevention and Control have not reported any CMNV-related cases, nor have they listed it as an urgent threat, the centers said.

The CDC said it assesses the risk of CMNV transmission in Taiwan as extremely low, but it would continue to monitor the situation with agricultural agencies.

The study said human CMNV infection might be associated with the handling or consumption of raw seafood, but evidence is still needed to confirm whether the virus is capable of infecting human ocular tissues, it said.

There have been no reports of large-scale outbreaks among humans or community spread of CMNV globally, the CDC said, adding that there is no evidence indicating that the consumption of thoroughly cooked seafood can cause infection.

While continuing to monitor for outbreaks around the world, the centers are developing detection and testing methods for humans and establishing criteria for specimen collection and submission, to enable risk monitoring and early warning, it said.

The Animal and Plant Health Inspection Agency's monitoring data shows there have been no confirmed cases of CMNV in shrimp farms in Taiwan, the CDC said.

The CDC advises travelers to these areas to exercise caution and take precautionary measures, such as cooking seafood thoroughly, or avoiding raw seafood altogether if they are high-risk individuals with chronic health conditions.

They should wear gloves when handling fresh seafood, it said, adding that if they are handling raw ingredients with open wounds, they should avoid direct contact and always wash their hands thoroughly with soap and water afterward to minimize the risk of pathogen exposure.