Recommendations on vaccination for Latin American small animal practitioners: a report of the WSAVA Vaccination Guidelines Group

Domestic Dog Infection with Trypanosoma cruzi from Northern and Southern Regions of Mexico

Background: Chagas disease or American trypanosomiasis, caused by Trypanosoma cruzi and vectored by triatomines, affects millions of people worldwide. In endemic countries including Mexico, infections in domestic animals, such as dogs, may affect the risk of human disease when they serve as a source of infection to vectors that subsequently infect humans. Materials and Methods: We conducted a cross-sectional study of 296 dogs from two cities near the northern and southern borders of Mexico: Reynosa, Tamaulipas, and Tuxtla Gutierrez, Chiapas. Infection was measured based on testing of blood using T. cruzi quantitative PCR (qPCR) and up to three antibody detection assays. The StatPak immunochromatographic assay was used to screen samples and the indirect fluorescent antibody (IFA) and multiplex microsphere immunoassay (MIA) tests were used as secondary tests on all samples that screened positive and a subset of negatives. Serologic positivity was defined based on reactivity on at least two independent tests. Results: Of the 280 samples tested for parasite DNA, two (0.7%) were positive, one of which (0.4%) was confirmed as T. cruzi discrete typing unit TcIV. Overall, 72 (24.3%) samples were reactive for T. cruzi antibodies via StatPak of which 8 were also positive using MIA and 2 were also positive using IFA (including one of the PCR-positive dogs). Overall, nine dogs (3.4%) met study criteria of positivity based on either/both serology or PCR tests. Positive dogs were found in both regions of Mexico; five (2.7%) from Reynosa and four (3.6%) from Tuxtla Gutierrez. We found no association between infection status and state of origin, sex, age group, breed group, neighborhood, and whether other pets lived in the home. Conclusion: Our results re-emphasize dogs' utility as sentinels for T. cruzi in Mexico and underscore the need for improved veterinary diagnostic tests and parasite surveillance at the household level in endemic countries.

Universal peptide-based potential vaccine design against canine distemper virus (CDV) using a vaccinomic approach

Canine distemper virus (CDV) affects many domestic and wild animals. Variations among CDV genome linages could lead to vaccination failure. To date, there are several vaccine alternatives, such as a modified live virus and a recombinant vaccine; however, most of these alternatives are based on the ancestral strain Onderstepoort, which has not been circulating for years. Vaccine failures and the need to update vaccines have been widely discussed, and the development of new vaccine candidates is necessary to reduce circulation and mortality. Current vaccination alternatives cannot be used in wildlife animals due to the lack of safety data for most of the species, in addition to the insufficient immune response against circulating strains worldwide in domestic species. Computational tools, including peptide-based therapies, have become essential for developing new-generation vaccines for diverse models. In this work, a peptide-based vaccine candidate with a peptide library derived from CDV H and F protein consensus sequences was constructed employing computational tools. The molecular docking and dynamics of the selected peptides with canine MHC-I and MHC-II and with TLR-2 and TLR-4 were evaluated. In silico safety was assayed through determination of antigenicity, allergenicity, toxicity potential, and homologous canine peptides. Additionally, in vitro safety was also evaluated through cytotoxicity in cell lines and canine peripheral blood mononuclear cells (cPBMCs) and through a hemolysis potential assay using canine red blood cells. A multiepitope CDV polypeptide was constructed, synthetized, and evaluated in silico and in vitro by employing the most promising peptides for comparison with single CDV immunogenic peptides. Our findings suggest that predicting immunogenic CDV peptides derived from most antigenic CDV proteins could aid in the development of new vaccine candidates, such as multiple single CDV peptides and multiepitope CDV polypeptides, that are safe in vitro and optimized in silico. In vivo studies are being conducted to validate potential vaccines that may be effective in preventing CDV infection in domestic and wild animals.

Canine parvovirus type 2 (CPV-2) serological and molecular patterns in dogs with viral gastroenteritis from southern Brazil

Canine Parvovirus type 2 (CPV-2) is a highly contagious virus that can cause severe systemic disease with gastroenteric symptoms in dogs, particularly in young puppies. Originating from the feline parvovirus in the late 1970s, it swiftly propagated globally, instigating a pandemic in dogs. Despite vaccination advancements, CPV-2 remains a substantial challenge for veterinary professionals and pet owners. This study aimed to contribute knowledge about the current situation of CPV-2 among dogs in southern Brazil. In this study, the sera of 125 dogs (mostly with gastroenteritis symptoms) were screened for antibodies against CPV-2 and their faeces for the virus itself. The results showed that 40% (50/125) of dogs were infected with CPV-2. Most animals (65.5%) had previously been exposed to CPV-2 (with serotitres equal or above 1:40), and only 37.6% had protective antibody titres equal or above 1:80. The findings have also demonstrated that vaccination against CPV-2 significantly reduced the risk of infection, with positive cases decreasing from 56.9% (unvaccinated) to 2.0% (fully vaccinated). Furthermore, the prevalence of CPV-2 decreased as dogs aged, with younger dogs and those with an incomplete or non-existent vaccination history at the highest risk of infection. In conclusion, this study provides valuable insight into the prevalence and risk factors associated with CPV-2 infection in dogs in southern Brazil, thereby providing valuable knowledge for the improvement of veterinary care and pet health.

Canine circovirus genomic characterization in dogs with and without diarrheal syndrome in Medellín, Colombia

Canine circovirus (CanineCV) is an emerging agent described for the first time in 2011, it infects domestic and wild canids, mainly associated with gastrointestinal signs; however, it has also been reported in samples obtained from animals without clinical signs, so its pathogenesis and epidemiology are still poorly understood. In Colombia, the CanineCV was first reported in 2020 from CPV-2 positive dogs. In the present work, CanineCV was detected in 30% of fecal samples obtained from dogs with or without diarrhea, in the city of Medellín, Colombia. No coinfection with CPV-2 was found. The highest number of positive samples was found in the subgroup of animals with diarrhea. Phylogenetic and evolutionary analyses confirmed the separation of the CanineCV genomes into five different clades with a European origin of the Colombian viruses and at least two different introductions of the CanineCV into the country. Our results highlight the importance of the CanineCV in Colombian dog populations and the need for continue surveillance of emerging pathogens in canine populations.

Canine parvovirus type 2 vaccines in Brazil: Viral load in commercial vaccine vials and phylogenetic analysis of the vaccine viruses

Canine parvovirus type 2 (CPV-2) is the etiological agent of a highly contagious and frequently fatal disease in dogs. Live attenuated vaccines (LAV) are recommended to prevent and control this disease. Commercial vaccines are typically produced with CPV-2 strains adapted to cell culture and usually non-pathogenic. The present study aimed to determine the viral load of CPV-2 vaccines commercially available in Brazil and to characterize the vaccine virus by DNA analysis of its capsid gene. The results demonstrated that all vaccine strains presented high homology of the VP2 gene and they were all closely related to the original CPV-2 strains. However, vaccine strains presented several differences in comparison with field strains currently circulating in Brazil. Seventy-one vials contained viral loads ranging from 7.4E3 to 4.9E10 DNA copies/ml. Nine vials did not contain any detectable CPV-2 DNA. In conclusion, there are genetic and antigenic differences among CPV-2 vaccines and field strains. Additionally, some vaccines have been commercialized with low titers of CPV-2. It is important to improve the quality of the vaccines to prevent or reduce the spread of CPV-2 in Brazil.

Preventive healthcare among dogs and cats in Chile is positively associated with emotional owner-companion animal bond and socioeconomic factors

Global companion animal population has been increasing as well as the number of dogs and cats being considered as a family member. However, it is unclear whether this close relationship could be associated with higher preventive healthcare in companion animals. Using data from 7,048 questionnaires of dogs and 3,271 of cats from the First National Study on Responsible Companion Animal Ownership, we estimated the proportion of preventive healthcare in companion animals of Chile. We also conducted a general linear mixed-effect regression model to identify socioeconomic factors and indicators of the emotional owners-companion animal bond that could influence owners' practices related to vaccination, parasite control, and veterinary visits. Based on the owner's answers, Chile has a satisfactory overall rates of parasite control (71%) and annual veterinary visits (65%) but a low vaccination coverage of both dogs (39%) and cats (25%). 'Purebred', 'live in urban areas', 'acquired by monetary compensation', and 'dog species' were associated with a higher probability of preventive healthcare in companion animals. Conversely, this probability was lower among senior animals compared to adults, males, and those owned by the Silent Generation or Baby Boomers (i.e., owners born before 1964). 'Sleeping inside', 'acquired for an emotional reason' (e.g., companionship), and 'considered a family member' were positively associated with at least one of assessed preventive measures. Our findings suggest that emotional owner-companion animal bonds could positively impact the frequency and quality of preventive healthcare in dogs and cats. However, owners who totally disagreed that a companion animal is a "family member" were also associated with a higher likelihood of vaccination uptake and veterinary visits for their animals. This highlights that owner's compliance with veterinary preventive healthcare is multifactorial. Chile has a high prevalence of infectious diseases circulating among dogs and cats and increasingly close contacts between owners and companion animals due to emotional bonds. Thus, our study calls for One Health approaches to reduce the risks of cross-species disease transmission. Specifically, increasing vaccination coverage of companion animals in Chile is the most urgent preventive measure needed, especially among cats, males, and older animals. Expand preventive healthcare among dogs and cats will promote public and animal health, including local wildlife that is susceptible to infectious diseases circulating in companion animals.

Exclusive circulation of canine parvovirus type 2c in the Guadalajara metropolitan area in western Mexico: a five-year study

Canine parvovirus type 2 (CPV-2) infection in dogs is associated with severe gastroenteritis, bloody diarrhea, and vomiting, resulting in high rates of death, especially in unvaccinated puppies within the first months of age. There are three variants, called CPV-2a, CPV-2b, and CPV-2c, co-circulating worldwide. Our group previously reported that the only circulating CPV-2 variant in the Guadalajara metropolitan area in western Mexico was type 2c. Now, a five-year study was performed in order to investigate the possible dominance of CPV-2c in our region. Rectal swabs were collected from 146 dogs with clinical gastroenteritis from May 2014 to August 2019 at the Veterinary Hospital of the University of Guadalajara. Of these, 90 dogs tested positive for canine parvovirus by PCR. Most of the infected dogs with CPV-2 had a partial or incomplete vaccination status (n = 88, 97.8%). Approximately 65% (n = 59) of them were mixed-breed dogs, 77.8% (n = 70) were under 6 months of age, and 37.8% (n = 34) of them died from clinical complications. RFLP analysis of amplicons derived from the vp2 gene showed that all 90 DNA samples corresponded to CPV-2c, with no evidence of the presence of CPV-2a or CPV-2b variants. Twenty-nine of the 90 DNA samples were selected for amplification of a portion of the vp2 gene, and sequencing of these amplicons showed that all of them had the sequence GAA at codon 426, encoding the amino acid glutamic acid, which is characteristic of CPV-2c. Phylogenetic analysis showed that the CPV-2c sequences were related to those of viruses from Europe and South America. The present study indicates that CPV-2c is still the only variant circulating in the dog population of the Guadalajara metropolitan area.

Improving the knowledge of high school students about zoonotic diseases from pets in Medellín-Colombia

BACKGROUND AND AIM

The "One Health" concept is a global strategy that recognizes that public health is related to animal health and the environment; however, the role of domestic animals and their involvement in the transmission of zoonoses is often underestimated. The aim of the study was to evaluate and improve the knowledge about zoonotic diseases of domestic animals in high school students from Medellín, Colombia.

MATERIALS AND METHODS

A quasi-experimental intra-subject study was carried out. This study was conducted with 11th-grade students from four schools in Medellín, Colombia. A structured multiple-choice questionnaire was used from March 2021 to May 2021. The research had two phases, first, "naive" knowledge and learning. Then, descriptive, association, and comparative analysis were carried out using absolute and relative frequencies, Pearson's Chi-square test, and MacNemar's test with a value of p<0.05 considered statistically significant.

RESULTS

A research poll from 315 students of four private schools found that feeding their pets with raw food and leftovers cooked for human consumption were common practices; the results also show a lack of knowledge of their pets' immunization deworming status. It was understood that when the students were able to identify at least two symptoms of zoonoses, one route of its' transmission and two preventive measures, we found that only 12.49% of the polled students had proper knowledge of the disease in domestic animals. After conducting an educational strategy, the findings show a general increase in knowledge, leading us to accept that the academic approach was adequate to statistically increase the recognition of symptoms, routes of transmission and preventive measures (p=0.00).

CONCLUSION

The use of the theoretical lecture is effective to improve the understanding of the concept of transmission of diseases from animals to humans; in addition, the results show an increase of knowledge in high school students of the related symptoms, transmission routes, and preventive measures of zoonoses diseases in the region.