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This is the first report on circulating canine rotavirus in Mexico. Fifty samples from dogs with gastroenteritis were analyzed used polymerase chain reaction and reverse transcription polymerase chain reaction in order to identify parvovirus and rotavirus, respectively; 7% of dogs were infected with rotavirus exclusively, while 14% were co-infected with both rotavirus and parvovirus; clinical signs in co-infected dogs were more severe.

Enteropathies in rabbits are difficult to diagnose; their etiology involves pathogens that act synergistically, causing damage to the intestine. The aim of the present study was isolate enteric pathogens from rabbits in Mexico. Using parasitological, bacteriological and molecular analyses, we screened 58 samples of the intestinal content of rabbits having a clinical history of enteric disease from the southeastern part of the State of Mexico. Out of the 58 samples analyzed, a total of 86 identifications were made, Eimeria spp. were found in 77.5%, followed by Aeromonas spp. in 15.5% and Escherichia coli in 8.6%, which were identified as enteropathogenic E. coli (EPEC), and the presence of the following agents was also confirmed: Salmonella spp., Klebsiella spp., Streptococcus spp., Staphylococcus aureus, Enterococcus spp., Mannheimia spp. and Rotavirus. The concurrent presence of Eimeria spp. with Aeromonas was frequent (15.5%); there was statistical significance for the presence of an association between the clinical profiles and Eimeria spp. (p = 0.000), Mannheimia spp. (p = 0.001), Salmonella spp., Klebsiella spp., Streptococcus spp. and Enterococcus spp. (p = 0.006).

Sarcoptic mange is a pruritic, contagious, ectoparasitic skin disease that affects mammals, including the domestic dog. The objective of this study was to evaluate and compare the efficacy of afoxolaner plus milbemycin oxime (NexGard Spectra) and afoxolaner alone (NexGard) as treatments for sarcoptic mange in naturally infested dogs. A total of 142 dogs naturally infested with Sarcoptes scabiei was evaluated. The dogs were diagnosed by microscopic examinations of skin scrapings. The dogs were divided into 2 groups: 96 dogs were treated with a combined dosage of 2.50 to 5.36 mg/kg body weight (BW) of afoxolaner and 0.50 to 1.07 mg/kg BW of milbemycin oxime and 46 dogs were treated with 2.50 mg/kg BW of afoxolaner alone. The presence or absence of pruritus and lesions were evaluated using an analogous scale on days 7, 14, 21, 28, and 56 after receiving the treatment. Data obtained were analyzed by Student’s t-test (P ≤ 0.05). The single oral treatment of afoxolaner plus milbemycin oxime resulted in a significant reduction in pruritus of 87.4% at 28 d after treatment (P ≤ 0.05). Resolution of the lesions after treatment was variable, with a significant decrease (P ≤ 0.05) observed within the first 14 d, although this parameter continued to improve until the end of the study on day 28, when a decrease of 96% was observed. By the end of the study, a single dose of either the afoxolaner alone or the afoxolaner combined with milbemycin oxime was effective in significantly reducing the signs associated with sarcoptic mange during a 56-day evaluation period.

Canine transmissible venereal tumour (CTVT) has been transmitted by cell transplantation from dog to dog, for over 10 000 years. Although initial studies report a single genetic origin for CTVT, recent samples from around the world reveal high genetic diversity. An elevated number of polymorphisms have been determined in mitochondrial DNA (mtDNA) of CTVT. The recent discovery of mtDNA transference from the host into tumoural cells could be a novel source of genetic diversity in CTVT. The aim of this study was to determine the presence of host mtDNA in samples of CTVT in Mexican dogs. Genotyping of 49 samples of CTVT and 49 samples of blood cells pertaining to affected dogs was performed by direct sequencing from the mtDNA D-loop region. Exogenous mtDNA was observed in 6% of the analysed tumours. This is the first investigation reporting the prevalence of exogenous mtDNA in CTVT in the Mexican dog population.

Canine transmissible venereal tumor (CTVT) is the only neoplasm that can be spread among dogs through cell transplantation. Therefore, this tumor does not originate from host cell transformation. Although CTVT has a monophyletic origin, several studies have shown the presence of genetic diversity which was probably acquired after the development of its original clone. To investigate the genetic diversity of CTVT in Mexico and its relation with CTVTs disseminated worldwide, we sequenced a fragment of mitochondrial DNA in 50 tumor samples and matched blood samples from dog hosts from Mexico. We found ten new haplotypes in tumor samples, which were all distinct from their matched host. The TVT1 haplotype was the most frequent in our samples, suggesting that it could be the origin of the others. We found that haplotypes in Mexico and other countries are distributed in two well-defined clusters. Our data also suggest a close relationship among American haplotypes (Mexico, USA, Chile and Brazil). Interestingly, these American haplotypes were also closely related to Asian haplotypes. Taking into account the estimated timing of the origin of CTVT, we propose that CTVT might have originated in Asia; consequently, haplotypes currently present in America could descend from Asiatic lineages.