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Diseases of molluscs

Viral diseases—Akoya oyster disease

Signs of disease

Important: animals with disease may show one or more of the signs below, but disease may still be present in the absence of any signs.

Clinical signs of disease in an infected animal
Gross signs of disease in an infected animal

Disease agent

Causative agent has not been identified, but is assumed to be viral.

Host range

Molluscs known to be susceptible to Akoya oyster disease:

Japanese pearl oyster (Akoya oyster)* (Pinctada fucata martensi)

*naturally susceptible

Presence in Asia–Pacific

Map showing presence in Asia–Pacific

Akoya oyster disease has been officially reported from Japan.


Differential diagnosis

The differential diagnostic table and the list of similar diseases appearing at the bottom of each disease page refer only to the diseases covered by this field guide. Gross signs observed might well be representative of a wider range of diseases not included here. Therefore, these diagnostic aids should not be read as a guide to a definitive diagnosis, but rather as a tool to help identify the listed diseases that most closely account for the gross signs.

Similar diseases

This disease should be suspected when mass mortality occurs only in Akoya oysters.

Sample collection

Because of uncertainty in differentiating diseases using only gross signs, and because some aquatic animal disease agents might pose a risk to humans, you should not try to collect samples unless you have been trained. Instead, you should phone your national hotline number and report your observations. If samples have to be collected, the agency taking the call will advise you on what you need to do. Local or district fisheries/veterinary authorities could advise you on sampling.

Emergency disease hotline

For your national emergency disease hotline number, see Whom to contact if you suspect a disease.

Further reading

The currently accepted procedures for a conclusive diagnosis of Akoya oyster disease are summarised at http://library.enaca.org/Health/DiseaseLibrary/AkoyaDisease.pdf

This hyperlink was correct and functioning at the time of publication.

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