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Fact sheet - Infectious Hypodermal and Haematopoitic Necrosis

What is Infectious Hypodermal and Haematopoitic Necrosis (IHHN)?

IHHN is an infectious disease that affects crustaceans. It is caused by the Infectious Hypodermal and Haematopoitic Necrosis Virus (IHHNV), which belongs to the family Parvoviridae and Genus Penstyldensovirus.

What species of crustaceans can be infected by IHHNV?

The species of crustaceans that can be infected by IHHNV are listed below:

Litopenaeus vannamei is currently the only species of shrimp cultured in land-based facilities in Canada. This species does not naturally exist in Canada's aquatic environment. None of the other susceptible species naturally exists in Canada.


The terms "shrimp" and "prawn" can both be used interchangeably.

Is IHHN a risk to human health?

No. IHHN cannot be transferred to humans and does not affect food safety.

What are the clinical signs of IHHN?

IHHNV causes disease that varies in severity in different shrimp species. For example:

Not all infected crustaceans will show clinical or visible signs of disease.

Is IHHN/IHHNV found in Canada?

In August 2019, IHHNV was confirmed in three provinces in land-based fully contained recirculating facilities culturing Litopenaeus vannamei. The outbreaks were linked to import of IHHNV-infected post-larvae of L. vannamei. The CFIA conducted responses at affected facilities to mitigate risk of disease spread.

How is IHHNV spread?

IHHNV is spread between crustaceans by:

Animals do not have to be visibly sick to transmit the virus. Animals that appear healthy can transmit the virus.
People can spread the disease by moving any of the following:

How is IHHN diagnosed?

IHHN may be suspected based on clinical signs. However, diagnosis of the disease must be confirmed by laboratory testing.

How is IHHN treated?

There are no treatment options currently available for IHHN.

What measures can be taken to prevent the introduction and spread of IHHN?

What is done to protect Canadian aquatic animals from IHHN?

IHHN is an immediately notifiable disease in Canada. Therefore any laboratory that diagnoses or suspects the appearance of IHHN in an animal is required by law to notify the CFIA.
If IHHN is found in Canada, the CFIA would implement disease response activities to help control its spread. These may include:

The chosen control measures would depend on the situation.

What do I do if I think crustaceans that I am raising or keeping have IHHN?

If you suspect a crustacean that you are raising or keeping may have IHHN, you should immediately consult your veterinarian or contact the nearest CFIA Animal Health Office.

How do I get more information?

Please visit Aquatic Animal Health for more information on reportable and notifiable diseases, or contact your local CFIA Animal Health Office to confirm the availability of inspection staff and office hours. Report suspected cases of federally reportable disease immediately to a CFIA district veterinarian.

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