Questions and Answers on Monkeypox and Animals

 What is monkeypox? 

Monkeypox is a viral zoonotic disease caused by infection with monkeypox virus that occurs primarily in tropical rainforest areas of Central and West Africa and is occasionally exported to other regions. Monkeypox virus belongs to the Orthopoxvirus genus in the family Poxviridae.
 
The Orthopoxvirus genus also includes variola virus (which caused smallpox, an eradicated disease), vaccinia virus (used in the smallpox vaccine), and cowpox virus.
 
In endemic areas, monkeypox virus is thought to be maintained in nature through circulation among a number of susceptible mammals, namely wild rodents (including squirrels and rats), with occasional spill-over to non-human primates and humans.How is monkeypox transmitted? 

Transmission of monkeypox virus can occur when a person or susceptible animal comes into contact with the virus from an animal, human, or materials contaminated with the virus. The virus enters the body through skin lesions (even if not visible to the naked eye), respiratory tract, or mucous membranes.
 
Monkeypox virus is transmitted from infected animals to humans or other susceptible animals by direct inoculation via bites, scratches or by direct contact with the body fluids and/or the meat of an infected animal during hunting and other activities involving susceptible animal species.
 
Human-to-human transmission occurs mainly through close physical contact (e.g., face-to-face, skin-to-skin, mouth-to-mouth, mouth-to-skin contact including during sex). Ulcers, lesions or sores present in the mouth or throat can be infectious, meaning the virus can spread through saliva and respiratory droplets (and possibly short-range aerosols), in some cases. More studies are needed on whether the virus can spread from breathing and talking.
 
Thus far, there is no documented evidence of human to animal transmission of monkeypox.Can animals be affected? 

Various wild mammals have been identified as susceptible to monkeypox virus. This includes rope squirrels, tree squirrels, Gambian pouched rats, dormice, non-human primates, among others. Although it may depend on the route of transmission and infectious dose, some species are asymptomatic, especially species suspected of being reservoirs (rodents). Other mammals, such as monkeys and great apes, show skin rashes similar to those experienced by humans.
 
Thus far, there is no documented evidence of domestic animals, such as cats and dogs, being affected by monkeypox virus. There is also no evidence or reports of livestock infection with monkeypox virus.How can monkeypox virus be detected in animals?

The appearance of clinical signs, including the presence of visible skin lesions, will depend on the species and age of the animal, as well as on the clade of monkeypox virus causing the infection. Species known as possible “reservoirs” will likely not present any clinical signs of infection. Detailed clinical signs per animal species can be consulted HERE  .

In species that present clinical signs of infection with monkeypox virus, animal health professionals should be on the lookout for:
– Increase in body temperature
– Appetite changes
– Conjunctivitis and/or ocular discharge
– Coughing or sneezing
– Abnormal sounds during auscultation of the lungs (this is not possible with the required PPE)
– Skin lesions with or without pruritus
– Palpable lymph nodes
 
Samples:
– Swabs taken from lesions
– Scabs
– Conjunctival swabs and/or oral and nasal secretions swabs
– Blood
 
Tests:
– Virus Neutralisation Test (VNT) is the recommended diagnostic test for detecting poxvirus antibodies. It takes 2-3 days to do an Orthopoxvirus VNT and a fluorescently tagged VACV strain can be used to make identification easier.
– PCR: a pan-pox PCR may be easier to find. However, a specific one to show which strain is causing the infection would be preferable.
– Serology: Orthopoxvirus ELISAsHow do we prevent future monkeypox virus spillovers?

Current monkeypox outbreaks outside of endemic areas appear to be driven by human-to-human transmission.

However, the virus has an animal origin. Good practices in interacting with wildlife, as described above, can reduce the risk of spillover events.

WOAH highlights that unregulated trade in wildlife (including wildlife meat and products) and other mammals can lead to the international spread of diseases such as monkeypox.