Expert science-please know: rabies risk of different kinds of animals

Expert profile: Researcher Dong Guanmu, postgraduate tutor, recipient of special allowance from the State Council, former director of the Vaccine Department of the China Food and Drug Control Institute, former member of the Veterinary Pharmacopoeia Committee of the Ministry of Agriculture, member of the Expert Committee for Disease Prevention and Control of the Ministry of Health, etc.; currently member of the National Pharmacopoeia Committee. Mainly engaged in viral vaccine research and vaccine quality control. During his work, he undertook a number of major national projects in the field of infectious diseases and vaccines, such as the Ninth five-year Plan, the Tenth five-year Plan, the Tenth 863-year Plan and the National Science and Technology support Plan, and won a number of national, provincial and ministerial science and technology awards.
The animal with the highest risk of rabies in the world is a dog, or why is it called "rabies?! The risk of rabies in animals other than dogs varies significantly around the world or in different regions, such as foxes in Europe, wolves in Central Asia, bats in Australia and South America, and so on. In theory, all terrestrial warm-blooded animals (those living on land) can suffer from rabies. In our country, it is mainly dogs and cats, as well as some small carnivorous wild animals in the south; while the risk of domestic pets, including rabbits, guinea pigs and other small animals is very small, but it cannot be absolutely ruled out. In addition to the characteristics of the animal species itself, the animal's living habits and activity environment largely determine the size of its risk.

The rabies virus, like all living things in the world, needs to constantly reproduce itself and the race will last forever. However, many animals except bats will definitely die as long as they get rabies, and it usually takes no more than 10 days from the onset of the disease to the death. Therefore, the rabies virus tries every means to make the animals infected with rabies virus get sick and go crazy, and bite other healthy animals to make themselves continue to the next animal. They pass on from generation to generation in this crazy way of reproduction; it is most easily spread in this way when the animals are in free contact. In virology it is called "cyclic infection" mode. In addition, small animals such as mice in the wild, because of their small size, cannot withstand the attack and bite of larger rabies-infected animals, and often die in one bite and die on the spot, so there is no threat to us humans as rabies-risk animals. This is also one of the reasons why rats and rabbits are often said to be low-risk animals for rabies, but once they get some opportunity to survive, they will become high-risk animals. Therefore, wild rats, rabbits, poultry and other animals cannot be absolutely ruled out. Will not spread rabies. [1]
In the United States, rabbits and guinea pigs were identified as rabies cases: for example, from 1992 to 2001, American scientists used sensitive fluorescence detection technology to confirm that 7 pet rabbits and 1 pet guinea pig had rabies. In particular, one of the rabbits was raised in the family yard and lived in a cage. When attacked by a wild animal with rabies, it had the opportunity to avoid the fatal attack of the wild rabies animal, and was infected by rabies virus and entered the incubation period. To a high-risk animal with illness, the owner found that the animal behaved abnormally and was injured, and sent it to the national laboratory for examination and confirmation of rabies, how dangerous it is to continue to let children play with them without vigilance! [2]

In addition, in the United States only in 2015, a total of 5491 animals were diagnosed with rabies by laboratory diagnosis, including 25 marmots, 1 squirrel, 2 beavers and 6 rabbits. [3]
Lishui City, Zhejiang Province, Henan Province and other places in China have also confirmed the existence of rabies virus in the brain tissue of wild mice, that is, wild mice may also be at risk of rabies. [4] [5] Poultry can also get rabies. In 2015, a hen was bitten by a stray dog on the chest in (Kerala), Kerala, India. The stray dog was missing. The owner gave the wound a simple treatment, but a month later the hen developed symptoms of listlessness and eventually died. The owner sent the chicken carcass to the Animal Husbandry Bureau for testing; the results confirmed that it was rabies; further analysis of the virus was the Indian subcontinent dog rabies virus strain, which proved that it was caused by mad dog bites. If free-range chickens and other poultry are attacked by other mad animals, they will also suffer from rabies. [6]
Therefore, it is feasible to assess the high or low risk of rabies exposure by animal species in general, but the risk of injury to animals in specific cases needs to be carefully evaluated and judged. Although domestic pet dogs and cats are classified as high-risk animals, if they are regularly vaccinated with guaranteed quality vaccines and have no chance of contact with wild/stray dogs and cats, their risk of rabies is very low. However, low-risk animals such as rabbits, poultry and rats may also become high-risk animals under certain circumstances. Although the incidence rate is very low, individual assessment should be required. In case of injury cases that may have contact with wild animals/stray dogs and cats or be attacked, and cannot be confirmed to exclude the risk of rabies exposure, the suspect should have principles to ensure the life safety of each patient injured by animals. To sum up, how do we evaluate the high or low risk of a special case of an injured animal? If an injured animal has the following behaviors, regardless of the type of the animal, it should be highly suspected that the animal may be suffering from rabies. If we may have come into contact with the animal, especially if saliva has contaminated the wound, mucous membrane and other parts, we should go to a professional animal injury clinic for rabies exposure treatment:

1. Animals that are normally active during the day become active during the night and salivate too much (drool)

2. Wild animals are not afraid of people

3. Animals cannot lie down for unknown reasons

4. Animals are timid when exposed to water or light.

5. The animal is suddenly aggressive, or nibbles and bites everywhere.

6. The pet is suddenly not close to the owner

7. Abnormal behavior such as making unusual noises [7]

References:

[1]PamelaJ. et al;Rabies Clinical Considerations and Exposure Evaluations,2020, P.79 https://doi.org/10.1016/B978-0-323-63979-8.00006-4

[2]Eidson M, et al. Rabies virus infection in a pet guinea pig and seven pet rabbits.JAVMA.2005;227(6):932–935.

[3]Weekly/ August 11, 2017 / 64(53);1–143,    

https://www.cdc.gov/mmwr/volumes/64/wr/mm6453a1.htm?s_cid=mm6453a1_w

[4] Investigation of rat rabies infection rate in Lishui City, Zhejiang Province. Chinese Journal of Natural Medicine 2009,11(5):349

[5] Comparative analysis of the main functional areas of the G gene of bovine and murine rabies virus in Henan. Journal of Animal Husbandry and Veterinary Medicine, 1998(4)):355-360

[6]Natural Rabies Infection in a Domestic Fowl (Gallus domesticus): A Report from India； https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511517/

[7]PAMELA J. et al.Rabies Postexposure Prophylaxis: Who, What, When, Where, Why,and How , in Rabies:Clinical Considerations and Exposure Evaluations.Copyright © 2019 Elsevier, Inc. All rights reserved.www.elsevier.com/permissions

Editor's note: Mice, rabbits, etc. are indeed low-risk animals, but in some abnormal situations, standard post-exposure disposal is still required. Previously we thought that birds could not get rabies, but new evidence shows that birds can also get rabies. With the in-depth study of scientists, rabies will eventually find a cure.