Canine Distemper Virus: Origins, Mutations, Diagnosis, and Epidemiology in Mexico.

This review provides an overview of the canine distemper virus (CDV), a highly infectious pathogen causing severe disease in domestic dogs and wildlife. It shares genetic similarities with the human measles virus (HMV) in humans and the rinderpest virus (RPV) in cattle. The origin of CDV likely involves a mutation from human measles strains, possibly in the New World, with subsequent transmission to dogs. CDV has been globally observed, with an increasing incidence in various animal populations. Genomic mutations, especially in the H protein, contribute to its ability to infect different hosts. Diagnosis by molecular techniques like RT-qPCR offers rapid and sensitive detection when compared with serological tests. Genomic sequencing is vital for understanding CDV evolution and designing effective control strategies. Overall, CDV poses a significant threat, and genomic sequencing enhances our ability to manage and prevent its spread. Here, the epidemiology of CDV principally in Mexico is reviewed.

Discovery of Novel Viruses in Culicoides Biting Midges in Chihuahua, Mexico.

Biting midges (Culicoides) are vectors of many pathogens of medical and veterinary importance, but their viromes are poorly characterized compared to certain other hematophagous arthropods, e.g., mosquitoes and ticks. The goal of this study was to use metagenomics to identify viruses in Culicoides from Mexico. A total of 457 adult midges were collected in Chihuahua, northern Mexico, in 2020 and 2021, and all were identified as female Culicoides reevesi. The midges were sorted into five pools and homogenized. An aliquot of each homogenate was subjected to polyethylene glycol precipitation to enrich for virions, then total RNA was extracted and analyzed by unbiased high-throughput sequencing. We identified six novel viruses that are characteristic of viruses from five families (Nodaviridae, Partitiviridae, Solemoviridae, Tombusviridae, and Totiviridae) and one novel virus that is too divergent from all classified viruses to be assigned to an established family. The newly discovered viruses are phylogenetically distinct from their closest known relatives, and their minimal infection rates in female C. reevesi range from 0.22 to 1.09. No previously known viruses were detected, presumably because viral metagenomics had never before been used to study Culicoides from the Western Hemisphere. To conclude, we discovered multiple novel viruses in C. reevesi from Mexico, expanding our knowledge of arthropod viral diversity and evolution.

Possible Association between Selected Tick-Borne Pathogen Prevalence and Rhipicephalus sanguineus sensu lato Infestation in Dogs from Juarez City (Chihuahua), Northwest Mexico-US Border.

Tick-borne bacterial pathogens (TBBPs) show a worldwide distribution and represent a great impact on public health. The brown dog tick (Rhipicephalus sanguineus) is a vector of several pathogens that affect dogs and sometimes humans as well. In addition, TBBPs represent a diagnostic challenge and imply financial resources and medical treatment for long periods of time. In the present study, R. sanguineus s. l. was identified as the main tick species naturally parasitizing dogs that inhabit. Juárez City, Chihuahua, in the Paso del Norte region, Mexico-US Border, representing 99.8% of the cases. Additionally, an end-point PCR was performed to search for whether pathogens in R. sanguineus s. l. can transmit in DNA extracted from ticks and dog blood samples. This is the first molecular detection of Rickettsia rickettsi infecting domestic dogs in Mexico; however, other pathogens were also identified, such as Ehrlichia canis and Anaplasma platys in both ticks and dog blood samples, while Anaplasma phagocytophilum was identified only in dog blood samples. Moreover, co-detection in tick pools and co-infection in the analyzed dog blood samples could be found. Similarly, this research showed that dogs were found mostly parasitized by adult female ticks, increasing the possibility of transmission of E. canis.

Molecular Detection of Tick-Borne Pathogens in American Bison (Bison bison) at El Uno Ecological Reserve, Janos, Chihuahua, Mexico.

American bison (Bison bison) is listed as near-threatened and in danger of extinction in Mexico. Recent studies have demonstrated the presence of several emerging pathogens at the Janos Biosphere Reserve (JBR), inhabited by one wild herd of American bison. Blood samples were collected from 26 American bison in the JBR. We tested for the presence of Anaplasma marginale, Babesia bigemina, B. bovis, Borrelia burgdorferi sensu lato, and Rickettsia rickettsii DNA using nested and semi-nested PCR protocols performing duplicates in two different laboratories. Results showed three animals (11.5%) positive for B. burgdorferi s. l., three more (11.5%) for Rickettsia rickettsii, and four (19.2%) for B. bovis. Two individuals were co-infected with B. burgdorferi s. l. and B. bovis. We found no animals positive for A. marginale and B. bigemina. This is the first report in America of R. rickettsii in American bison. American bison has been described as an important reservoir for pathogens of zoonotic and veterinary importance; thus, the presence of tick-borne pathogen DNA in the JBR American bison indicates the importance of continuous wildlife health surveys.

Detection of Antibodies to Lokern, Main Drain, St. Louis Encephalitis, and West Nile Viruses in Vertebrate Animals in Chihuahua, Guerrero, and Michoacán, Mexico.

We conducted serologic surveillance for flaviviruses and orthobunyaviruses in vertebrate animals in Mexico in 2018-2019. Sera were collected from 856 vertebrate animals, including 323 dogs, 223 horses, and 121 cows, from 16 species. The animals were from 3 states: Chihuahua in northwest Mexico (704 animals) and Guerrero and Michoacán on the Pacific Coast (27 and 125 animals, respectively). Sera were assayed by plaque reduction neutralization test using four flaviviruses (dengue type 2, St. Louis encephalitis, West Nile, and Zika viruses) and six orthobunyaviruses from the Bunyamwera (BUN) serogroup (Cache Valley, Lokern, Main Drain, Northway, Potosi, and Tensaw viruses). Antibodies to West Nile virus (WNV) were detected in 154 animals of 9 species, including 89 (39.9%) horses, 3 (21.4%) Indian peafowl, and 41 (12.7%) dogs. Antibodies to St. Louis encephalitis virus (SLEV) were detected in seven animals, including three (0.9%) dogs. Antibodies to Lokern virus (LOKV) were detected in 22 animals: 19 (8.5%) horses, 2 (1.7%) cows, and a dog (0.3%). Antibodies to Main Drain virus (MDV) were detected in three (1.3%) horses. WNV and LOKV activity was detected in all three states, SLEV activity was detected in Chihuahua and Michoacán, and MDV activity was detected in Chihuahua. None of the animals was seropositive for Cache Valley virus, the most common and widely distributed BUN serogroup virus in North America. In conclusion, we provide serologic evidence that select flaviviruses and BUN serogroup viruses infect vertebrate animals in Chihuahua, Guerrero, and Michoacán. We also provide the first evidence of LOKV and MDV activity in Mexico.

Demonstrating the presence of Ehrlichia canis DNA from different tissues of dogs with suspected subclinical ehrlichiosis.

BACKGROUND: Nowadays, Ehrlichia canis receives increasing attention because of its great morbidity and mortality in animals. Dogs in the subclinical and chronic phases can be asymptomatic, and serological tests show cross-reactivity and fail to differentiate between current and past infections. Moreover, there could be low parasitaemia, and E. canis might be found only in target organs, hence causing results to be negative by polymerase chain reaction (PCR) on blood samples. METHODS: We evaluated by PCR the prevalence of E. canis in blood, liver, spleen, lymph node and bone marrow samples of 59 recently euthanised dogs that had ticks but were clinically healthy. RESULTS: In total, 52.55% of the blood PCRs for E. canis were negative, yet 61.30% yielded positive results from tissue biopsies and were as follows: 63.15% from bone marrow; 52.63% from liver; 47.36% from spleen; and 15.78% from lymph node. In addition, 33% had infection in three tissues (spleen, liver and bone marrow). CONCLUSIONS: Our results show the prevalence of E. canis from tissues of dogs that were negative by blood PCR. Ehrlichia canis DNA in tissue was 30% lower in dogs that tested negative in PCR of blood samples compared to those that were positive. However, it must be taken into account that some dogs with negative results were positive for E. canis in other tissues.

Evaluation of a Bochdalek diaphragmatic hernia rabbit model for pediatric thoracoscopic training.

BACKGROUND/AIM: This study evaluated the usefulness of a Bochdalek hernia rabbit model as a tool for advanced thoracoscopic training, teaching the specific skills required for thoracoscopic repair of congenital diaphragmatic hernia. MATERIALS AND METHODS: An incision was made in the Bochdalek triangle of 25 New Zealand rabbits (weighing 3-3.5 kg) to induce an experimental diaphragmatic hernia. At 72 hours later, a thoracoscopic repair of the hernia as described for newborns was performed by 25 pediatric surgeons divided into two groups: expert and novice. The tasks assessed were organ relocation and diaphragm suture. A visual analog scale was used to evaluate technical performance. The objective performance measure was completion time. Complications were recorded, and suture quality was scored. The surgeons evaluated the model by completing a questionnaire, grading items on a 5-point scale. RESULTS: All 25 animals developed a diaphragmatic hernia with protrusion of the intestine into the thoracic cavity. Expert trainees had significantly shorter completion times and better performance scores than novices. Experts also received higher scores for suture quality. Five novices caused perforations or bleeding, but no experts did. The surgeons rated the model positively, highlighting the similarities between the model and newborn hernias and its usefulness for pediatric training programs. CONCLUSIONS: The Bochdalek hernia rabbit model can be used to detect different levels of experience in pediatric thoracoscopy. This realistic and easily reproducible model can help to perfect thoracoscopic skills in a realistic recreation of a pediatric Bochdalek hernia repair.

Development of an optimal diaphragmatic hernia rabbit model for pediatric thoracoscopic training.

Our objectives were to standarize the procedure needed to reproduce a similar surgical scene which a pediatric surgeon would face on repairing a Bochdalek hernia in newborns and to define the optimal time period for hernia development that achieve a realistic surgical scenario with minimimal animal suffering. Twenty New Zealand white rabbits weighing 3-3.5 kg were divided into four groups depending on the time frame since hernia creation to thoracoscopic repair: 48 h, 72 h, 96 h and 30 days. Bochdalek trigono was identified and procedures for hernia creation and thoracoscopic repair were standarized. Blood was collected for hematology (red blood cells, white blood cells, platelets, hemoglobin and hematocrit), biochemistry (blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and creatine kinase) and gas analysis (arterial blood pH, partial pressure of oxygen, partial pressure of carbón dioxide, oxygen saturation and bicarbonate) at baseline and before the surgial repairment. Glucocorticoid metabolites concentration in faeces was measured. Thoracoscopy video recordings were evaluated by six pediatric surgeons and rated from 0 to 10 according to similarities with congenital diaphragmatic hernia in newborn and with its thoracoscopic approach. Statistical methods included the analysis of variance, and comparisons between groups were followed by a post-hoc Tukey's test. Fourty -eight h showed to be the optimal time frame to obtain a diaphragmatic hernia similar to newborn scenario from a surgical point of view with minimal stress for the animals.

Gastroesophageal reflux in anesthetized dogs: a review / Reflujo gastroesofágico en perros anestesiados: revisión de literatura / Refluxo gastroesofágico em cães anestesiados: revisão de literatura

Gastroesophageal reflux can be a catastrophic illness in small animals during anesthesia since its complications can cause serious pathologies, such as esophagitis, esophageal stenosis and aspiration pneumonia. With an incidence from 12 to 78.5% in anesthetized dogs, gastroesophageal reflux is normally silent during anesthesia and will be notices only if regurgitation occurs and stomach acid is present in the nasal or oral cavities. In humans, gastroesophageal reflux disease (GERD) is a well-defined pathology where the lower esophageal sphincter has a sustained weakness. However, in dogs, gastroesophageal reflux disease as such is not well established, if at all; it has only been described as gastroesophagic reflux, occurring principally in anesthetized animals. There are several factors influencing the presentation of reflux in anesthetized dogs, which may be inherent to the patient (e.g. age, sex, breed, weight, or body condition), medications used prior to and during anesthesia, type of surgery or position of the animal during surgery. The objective of this review is to discuss a series of conditions that could predispose dogs to gastroesophageal reflux during anesthesia and to assist in the prevention and diagnosis of this condition.

El reflujo gastroesofágico durante la anestesia puede ser una entidad catastrófica en la clínica de pequeñas especies, ya que sus complicaciones derivan en entidades realmente graves como esofagitis, estenosis esofágica y neumonía por aspiración. Con una incidencia del 12 al 78.5% en perros anestesiados, el reflujo gastroesofágico durante la anestesia es generalmente silencioso y sólo se observa cuando existe regurgitación y el reflujo pasa a cavidad oral o nasal. En el humano, la enfermedad por reflujo gastroesofágico (ERGE) es una patología bien definida, donde el esfínter esofágico inferior presenta una debilidad sostenida. Sin embargo, en el perro esta enfermedad como tal no está bien establecida, si acaso se describe el reflujo gastroesofágico, que ocurre principalmente en animales anestesiados. Existen diversos factores que influyen en la presentación del reflujo en los perros anestesiados. Estos pueden ser inherentes al paciente (por ejemplo: edad, sexo, raza, peso o condición corporal), a medicamentos utilizados previamente y durante la anestesia, al tipo de cirugía o a la posición del animal durante la cirugía. El objetivo de esta revisión es discutir una guía de las condiciones que predisponen a la aparición de reflujo gastroesofágico durante la anestesia en perros con el fin de facilitar el diagnóstico y la prevención de esta condición.

O refluxo gastroesofágico durante a anestesia pode ser uma entidade catastrófica na clínica de pequenas espécies, já que suas complicações resultam em entidades realmente graves, como esofagite, estenose esofágica e pneumonia por aspiração. O refluxo gastroesofágico em cães anestesiados é geralmente silencioso, com uma incidência de 12 até 78.5% e só é observada quando há regurgitação e o refluxo passa até a cavidade oral ou nasal. Nos humanos, a doença pelo refluxo gastroesofágico (ERGE) é uma patologia bem definida, onde o esfíncter esofágico inferior apresenta uma debilidade continua. Porém, esta doença em cães não está bem estabelecida, pelo qual só se descreve o refluxo gastroesofágico, que ocorre principalmente em animais anestesiados. Existem diversos fatores que influenciam na apresentação do refluxo em cães anestesiados. Estes podem ser inerentes ao paciente (por exemplo: idade, sexo, raça, peso ou condição corporal), a medicamentos utilizados previamente e durante a anestesia, ao tipo de cirurgia ou a posição do animal durante a cirurgia. O objetivo da revisão foi discutir uma guia das condições que predispõem à aparição de refluxo gastroesofágico durante a anestesia em cães com o fim de facilitar o diagnóstico e a prevenção dessa condição.