Myxomatosis is a viral disease, whose responsible virus can be classified as one of the largest existing viruses belonging to the family Poxviridae. This family has two subfamilies, the Chordopoxvirinae, which affects vertebrates, and the Entomopoxvirinae, which affects insects. The viral genome is composed of a single molecule of linear DNA with a double chain, besides having a structure called "virion", which gives the virus a greater amount of enzymes and auxiliary factors. The reproductive cycle is entirely in the cytoplasm of the host cell. The virus has a rectangular or ovoid shape with complex symmetry, usually coated with a lipid envelope. Poxviruses affect different classes of animals and have great zoonotic potential (FLORES, E. C, 2007).
Pathogenesis occurs from direct contact with rabbits or arthropod vectors (mosquitoes, mites, fleas, lice and flies) contaminated by the Myxoma virus. The clinical signs are specific, fever, serous ocular discharge to mucopurulent productive blepharoconjunctivitis, edema in the conjunctival, nasal, labial, auricular and genital regions. It is also common, the formation of vesiculate and gelatinous papules in these mucous membranes, which tend to generalize giving an aspect called "leonine face". The diagnosis is made by histopathological methods, such as PCR, electron microscopy, ELISA and complement fixation test. The disease control is given by the control of rabbits infected with the virus (MYXV), and by euthanasia in affected animals. Myxomatosis is a mandatory disease according to the World Organization for Animal Health (AZEVEDO, J.B. et al, 2014; ANDRADE, A. et al. ANO).
In March 2019, an adult male hedgehog (Coendou prehensilis) with edema in the palpebral, labial, scrotal and perianal region was received at the Federal University of Uberlândia (UFU) wildlife outpatient clinic. The animal also had hyperemia and palpebral and nasal ulceration, as well as mucopurulent ocular and nasal secretion (SCHLEMPER, A. E. et al, 2021). The hedgehog was initially treated for anaphylactic shock, but died after four days. Due to the similarity of clinical signs with the rabbit myxoma, necropsy and histopathological examination was performed, with the discovery of a new poxvirus. Molecular analysis of tissue samples and phylogenetic study are described in the work of Hora et al (2021).
The discovery of a new species of poxvirus, causing severe disease in hedgehogs should be surrounded by caution. Regardless of the origin, its zoonotic potential should be monitored, given that viruses from this family have already had a great impact on human health, such as smallpox (HOCHMAN, 2011). This finding reinforces the importance and care that should be given to wildlife management at the interface with anthropogenic areas.
Author: Joana de Bairros Neris - Secretary Director of GEAS Brazil
Review: Iago Junqueira - GEAS Brazil Partner for The Wild Place
Wild Panel of December/2024
Bibliographical References:
FLORES, E. C. Virologia Veterinária. Ed. UFSM, Santa Maria, 2007
AZEVEDO, J.B. et al. Mixomatose em coelho doméstico criado como animal de estimação em Mato Grosso. PUBVET, Londrina, V. 8, N. 7, Ed. 256, Art. 1694, Abril, 2014.
ANDRADE, A., PINTO, SC. e OLIVEIRA, R. S. Principais Doenças dos Coelhos. Animais de Laboratório, p. 105. 2002. ISBN: 85-7541-015-6. Editora Fiocruz. Rio de Janeiro.
HOCHMAN G. Vacinação, varíola e uma cultura da imunização no Brasil. Ciência e Saúde coletiva. v.16 n.2. p. 375-386. 2011. DOI: https://doi.org/10.1590/S1413- 81232011000200002
HORA A. S., TANIWAKI S. A., MARTINS N. B., PINTO N. N. R., SCHLEMPER A. E., SANTOS A. L. Q., SZABÓ M. P. J., BRANDÃO P. E. Genomic Analysis Of A Novel Poxvírus Brazilian Porcupinepox Virus. Emerging Infectious Diseases. v.27 n.4. 2021. ISSN: 1080-6059
SCHLEMPER, André Eduardo. Aspectos clínico-patológicos da infecção de ouriço-cacheiro de vida livre (Coendou prehensilis) com poxvirus (Brazilian Porcupine Poxvirus - BPOPV). 2021. 14 f. Trabalho de Conclusão de Residência (Residência em Medicina Veterinária) – Universidade Federal de Uberlândia, Uberlândia, 2021.
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