Scientists flag lack of monitoring of Hepatitis A contamination in PH shellfish

Not much is known about how Hepatitis A virus (HAV) can be transmitted through local shellfish due to a lack of monitoring efforts, according to scientists.

This was pointed out in a study by experts from the Ateneo de Manila University, the University of the Philippines, Monash University Malaysia Selangor, and the Bureau of Fisheries and Aquatic Resources.

“The fact that Hepatitis A is very contagious (can be spread easily by infected persons even without symptoms) and that Filipinos living along the coastal areas are susceptible to contaminated fresh products still renders significant public concern,” the scientists said in a study published in the Philippine Journal of Science in August 2024.

Hepatitis A, which is caused by HAV, is a liver disease. According to the US Centers for Disease Control and Prevention, an infected person ''may feel sick for a few weeks or several months but usually recover completely and do not have lasting liver damage,'' but in ''rare cases, hepatitis A can cause liver failure and even death.''

Among the primary causes of HAV contamination in shellfish is their environment. Experts noted that shellfish culturing sites in the Philippines are associated with polluted shallow coastal areas near industrial and household sites.

“HAV is particularly high from ingesting poorly prepared shellfish such as oysters and mussels, since these animals are filter feeders that process large amounts of potentially contaminated water,” the Ateneo de Manila Research Communications said.

“The virus can also survive for up to ten weeks inside shellfish, greatly increasing the possibility of spreading and further contamination.”

Freezing storage, depuration, and standard cooking protocols for processed shellfish “do not guarantee a complete HAV inactivation in shellfish,'' the scientists said, citing studies.

While there are regulations and food safety controls in the Philippines, the scientists said that local shellfish are only assessed for E. coli and salmonella.

They said ''such tests do not adequately reflect the presence of HAV and other viruses.''

“Perceived health risks related to seafood consumption are limited to red tide or mass fish kill, which are well-documented and publicized for consumer information,” the study said.

“Baseline information relevant to HAV concentration in shellfish products should be established by including HAV in the monitoring of BFAR, and shellfish food safety should not solely rely on bacterial indicators such as salmonella, E. coli, and fecal coliforms both in shellfish and seawater samples,'' it added.

''There are also no consistent monitoring programs for HAV in local shellfish and the environment, hampering the early identification of potential outbreaks.''

Further, the scientists said that “additional studies should be conducted to determine the effect of different food processes, cooking practices, and storage conditions on the HAV concentration.”

''Consumer risk perception towards HAV should also be integrated to increase the awareness of consumers relevant to the safety of shellfish products,'' the study said.

Although there is no specific treatment for Hepatitis A, the World Health Organization said HAV infection can be prevented through improved sanitation, food safety, and immunization. —VBL, GMA Integrated News