Ostreid Herpesvirus-1 May Pose Threat to U.S. Shellfish,
But Does NOT Harm Humans

Ostreid herpesvirus-1 (OsHV-1) is a virus affecting many types of bivalve shellfish. Although the virus does NOT affect humans, it has caused mass mortalities of shellfish around the world and poses a significant threat to a wide variety of shellfish that grow in U.S. waters. It can be carried in live or frozen shellfish imported from the regions of the world where it is present.

From 2001-2003 a less-virulent strain of the ostreid herpesvirus  was discovered to be associated with larval Pacific oyster mortalities in California.

In the U.S. commercially cultured shellfish that may be susceptible to infection include Eastern oysters,  Pacific oysters, European flat oysters, Kumamoto oysters, Mediterranean mussels, scallops, abalone and Manila clams.

The USDA's Animal and Plant Health Inspection Service has more information posted on its Aquatic Animal Diseases webpage under the Mollusk Diseases tab.  Below are  direct links to some of those pages.


Ostreid Herpesvirus-1 Info Sheet

The U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) has published this useful information sheet covering the background of the disease, transmission and clinical signs of infection,  control and prevention methods, and what to do if you suspect you have a infected animals.

Transmission Routes

APHIS explains how OsHV-1 could be transmitted to susceptible shellfish populations in this document.

FAQs About OsHV-1 Microvariants and Pacific Oyster Mortality Syndrome (POMS)

Infections with ostreid herpesvirus-1 (OsHV-1) microvariants (closely related variants of OsHV-1) have been reported in several bivalve species. APHIS answers frequently asked questions in this document.

Optimizing surveillance for early disease detection: Expert guidance for Ostreid herpesvirus surveillance design and system sensitivity calculation

Read a paper on surveillance for early disease detection that was published in the September 2021 edition of Preventive Veterinary Medicine.

How Shellfish Dealers and Importers Can Help Protect U.S. Shellfish

The East Coast Shellfish Growers Association, Pacific Coast Shellfish Growers Association and Oyster South teamed up to pen a letter to shellfish dealers and importers alerting them to take certain precautions to remain in compliance with U.S. regulations such as the Clean Water Act and the Lacey Act. The letter urges dealers and importers of foreign shellfish to order free tags that will inform the public about how to protect U.S. shellfish farms and natural resources from possible pathogens imported from abroad.

The Impacts of Ostreid Herpesvirus-1 Microvariants on Pacific Oyster Aquaculture in the Northern and Southern Hemispheres Since 2008

This paper by M. Fuhrmann et al., posits that there may be opportunities for better coordination of industry and government responses to epizootic disease emergence in aquaculture. The authors point out the need for increased adoption of technical advances from research, once these solutions have been adequately verified.