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Characterization of the Hemagglutinin Gene of Morbillivirus Canis in Domestic Dogs from the Mid-Western Area of Brazil
by
, , , , , , and
Mayara Lima Kavasaki
1,2, 
Aneliza de Oliveira Souza
2,
Amanda Noeli da Silva Campos
2,
Isis Indaiara Gonçalves Granjeiro Taques
2,
Rachel Vieira Paes de Barros
2,
Sofia de Souza Pereira Gomes
2,
Nathalia Assis Pereira
2,
Tayane Bruna Soares Magalhães
2,
Edson Viana Massoli Junior
2,3,
Lucas Avelino D. Pavelegini
2,
Luiz Donizete Campeiro Junior
1,
Bruno Gomes de Castro
4,
Michele Lunardi
5,6 and
Daniel Moura de Aguiar
2,*
1
Marechal Rondon Faculty, Veterinary Medicine College, Vilhena 76980-000, RO, Brazil
2
Laboratory of Virology and Rickettsiosis, Faculty of Veterinary Medicine, Federal University of Mato Grosso State, Cuiabá 78600-000, MT, Brazil
3
School of Agricultural, Biological and Engineering Sciences, University Center of Várzea Grande, UNIVAG, Várzea Grande 78118-900, MT, Brazil
4
Veterinary Medicine College, UFMT, Sinop 78550-728, MT, Brazil
5
Post Graduate Program in Animal Health and Production, Department of Agrarian Sciences, University Pitagoras Unopar, Arapongas 86702-670, PR, Brazil
6
Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Londrina State University, Londrina 86057-970, PR, Brazil
*
Author to whom correspondence should be addressed.
Vet. Sci. 2025, 12(10), 948; https://doi.org/10.3390/vetsci12100948
Submission received: 9 September 2025
/
Revised: 26 September 2025
/
Accepted: 29 September 2025
/
Published: 30 September 2025
(This article belongs to the Section Veterinary Microbiology, Parasitology and Immunology)
Simple Summary
Canine distemper is a serious and often fatal disease that affects domestic dogs and wild animals. It can cause respiratory problems, neurological symptoms, and death. In this study, we examined brain samples from dogs that died with signs of nervous system disease in two regions of Brazil. We looked for the virus that causes canine distemper and studied the genetic material of one of its proteins, which helps the virus enter the animal’s cells. Our results showed that the virus found in these animals is related to strains already circulating in Brazil, Argentina, and Uruguay. By understanding the genetic differences between strains of this virus, we can better track its spread, monitor the risks for domestic and wild animals, and improve prevention strategies such as vaccination. This research helps protect animal health and supports public health efforts, especially in areas where the canine distemper virus is common.
Abstract
Canine distemper virus (CDV) is a serious and often fatal disease caused by Morbillivirus canis, which affects domestic dogs and wild carnivores, with case-fatality rates reaching up to 47%. The hemagglutinin (H) protein mediates viral adsorption and shows high genetic variability, making it a valuable molecular marker. This study aimed to detect and characterize the H gene of CDV strains from 14 dogs with fatal neurological disease in the Brazilian states of Mato Grosso and Rondônia. Brain tissue was tested via RT-PCR for the nucleocapsid gene, and positive samples were amplified for the H gene. Ten complete H-gene sequences were obtained. Phylogenetic analysis revealed two distinct clusters within the South America I/Europe lineage: one related to strains from Uruguay and Argentina (with residues 530G/549Y) and another related to Brazilian strains (530S/549Y). One sequence (MT8) showed an intermediate position in the haplotype network but clustered phylogenetically with Uruguay/Argentina-related strains. Most sequences carried 530S/549Y, a pattern linked to altered SLAM receptor usage in wildlife. These findings demonstrate the co-circulation of two CDV clusters in Central–Western Brazil, their regional and international genetic connectivity, and amino acid substitutions potentially influencing host adaptation and antigenicity.
Keywords:
canine distemper; genetic lineages; RT-PCR; phylogenetic analysis
