Bovine viral diarrhea virus (BVDV) infects cattle populations worldwide, causing significant economic losses though its impact on animal health. Previous studies have reported the prevalence of BVDV species and subgenotypes in cattle from the United States and Canada. We investigated the genetic diversity of BVDV strains detected in bovine serum samples from 6 different Mexican regions. Sixty-two BVDV isolates from Mexico were genetically typed based on comparison of sequences from the 5' untranslated region (5'-UTR) of the viral genome. Phylogenetic reconstruction indicated that 60 of the samples belonged to the BVDV-1 genotype and 2 to the BVDV-2 genotype. Comparison of partial 5'-UTR sequences clustered 49 samples within BVDV-1c, 8 samples within BVDV-1a, 3 samples within BVDV-1b, and 2 samples clustered with the BVDV-2a subgenotypes. Our study, combined with information previously published on BVDV field strain diversity in the United States and Canada, benefits the development of effective detection assays, vaccines, and control programs for North America.

Summary The genus Pestivirus within Flaviviridae is comprised of four recognized species, namely, bovine viral diarrhoea virus 1 (BVDV‐1), bovine viral diarrhoea virus 2 (BVDV‐2), border disease virus (BDV) and classical swine fever virus (CSFV). BDV, while primarily infecting sheep and goats, has also been reported in cattle and wild animals. Infections of sheep and goats result in economic loss due to abortions and the birth of persistently infected animals that have poor production and reduced life expectancy. In this study, we report the detection of BDV in cattle serum collected as part of pestivirus surveillance programme from six regions of Mexico, where a 67.1% of BVDV seroprevalence was calculated previously. Phylogenetic analyses based on comparison of the 5′UTR region typed the Mexican strains as BDV‐1. Border disease (BD) is listed as an exotic disease in Mexico, and the origin of BDV found in these cattle is unclear. This is the first identification of BDV in Mexican cattle.

In this communication, we report the presence of RNA of bovine viral diarrhea virus (BVDV) as a contaminant of different biological products used in Mexico for veterinary vaccine production. For this purpose, six batches of monovalent vaccines, eight cell line batches used for vaccine production, and 10 fetal bovine serum lots (FBS) commercially available in Mexico from different suppliers were tested by reverse transcription polymerase chain reaction (RT-PCR). Viral RNA was detected in 62.5% of the samples analyzed. Phylogenetic analysis revealed the presence of the subgenotypes BVDV-1a, 1b, and BVDV-2a in the tested samples. Collectively, these findings indicate that contamination by BVDV RNA occurs in commercial vaccines and reagents used in research and production of biological products. The ramifications of this contamination are discussed.

Bovine viral diarrhea (BVD) is an infectious disease, globally-distributed, caused by bovine Pestiviruses, endemic of cattle and other ruminant populations. BVD leads to significant economic losses to the cattle industry due to the wide range of clinical manifestations, including respiratory and gastrointestinal diseases and reproductive disorders. Within the Pestivirus genus of the family Flaviviridae three viral species are associated with BVD; Pestivirus A (Bovine viral diarrhea virus 1, BVDV-1), Pestivirus B (Bovine viral diarrhea virus 2, BVDV-2), and Pestivirus H (HoBi-like pestivirus, atypical ruminant pestivirus). These species are subdivided into subgenotypes based on phylogenetic analysis. The extensive genetic diversity of BVDV has been reported for several countries, where the incidence and genetic variation are more developed in Europe than in the Americas. The first report of BVDV in Mexico was in 1975; this study revealed seropositivity of 75% in cows with a clinical history of infertility, abortions, and respiratory disease. Other studies have demonstrated the presence of antibodies against BVDV with a seroprevalence ranging from 7.4 to 100%. Recently, endemic BVDV strains affecting cattle populations started to be analyzed, providing evidence of the BVDV diversity in several states of the country, revealing that at least four subgenotypes (BVDV-1a, 1b, 1c, and 2a) are circulating in animal populations in Mexico. Little information regarding BVD epidemiological current status in Mexico is available. This review summarizes available information regarding the prevalence and genetic diversity viruses associated with BVD in cattle from Mexico.

The Mexican lineage H7N3 highly pathogenic avian influenza virus (HPAIV) has persisted in Mexican poultry since its first isolation in 2012. To date, the detection of this virus has gradually expanded from the initial one state to 18 states in Mexico. Despite the HPAIV H7N3 outbreak occurring yearly, the transmission pathways have never been studied, disallowing the establishment of effective control measures. We used a phylogenetic approach to unravel the transmission pathways of 2022 H7N3 HPAIVs in the new outbreak areas in Northern Mexico. We present genetic data of H7N3 viruses produced from 18 poultry farms infected in the spring of 2022. Our results indicate that the virus responsible for the current outbreak in Northern Mexico evolved from the Mexican lineage H7N3 HPAIV discovered in 2012. In the current outbreak, we identified five clusters of infection with four noticeably different genetic backgrounds. It is a cluster IV-like virus that was transmitted into one northern state causing an outbreak, then spreading to another neighboring northern state, possibly via a human-mediated mechanical transmission mechanism. The long-distance transmission event highlights the necessity for the more rigorous enforcement of biosafety measures in outbreaks. Additionally, we examined the evolutionary processes shaping the viral genetic and antigenic diversities. It is imperative to enhance active surveillance to include birds, the environment, and humans to detect HPAI in domestic poultry at an earlier point and eliminate it.

SummaryA case of equine skunk‐associated rabies was diagnosed in Northern Mexico. A 4‐year‐old mare with clinical signs of ataxia, self‐mutilation, circling, prostration, anorexia, and death 3 days after the onset of the symptoms was reported. History and clinical signs were consistent with a neurological disease. Brain tissue was collected and examined to confirm the diagnosis. The tissue sample was positive for rabies using immunofluorescence assay; whole genome sequencing and viral isolation in suckling mice were performed. Genetic characterisation based on a fragment of the nucleoprotein sequence revealed that a skunk‐associated rabies virus caused infection in the mare. This report is considered important due to it not being related to bat rabies; therefore, identifying the rabies source species has significant implications for public health as well as veterinary consequences. There is a need for greater awareness regarding zoonotic risks, diagnostic assays, prophylactic measures and the establishment of specific procedures to limit horse attacks from rabid wildlife.

El virus de la diarrea viral bovina pertenece al género Pestivirus de la familia Flaviviridae. Los pestivirus infectan a un extenso rango de artiodáctilos, silvestres y domésticos, en los cuales ocasionan una gran variedad de desórdenes respiratorios, gastrointestinales y reproductivos que derivan en pérdidas relevantes para la industria pecuaria. El uso compartido de fuentes de agua y alimento entre los ambientes naturales y pecuarios incrementa el contacto directo e indirecto entre animales domésticos y silvestres, lo que aumenta el riesgo de transmisión interespecie de pestivirus. Por este motivo, la vigilancia de enfermedades causadas por pestivirus debería considerar la prevalencia de estos patógenos en animales silvestres. Actualmente se desconoce la diversidad genética de pestivirus en poblaciones silvestres en México. Este grupo de trabajo recolectó muestras de suero de 371 artiodáctilos silvestres en cautiverio en cuatro regiones de cuatro estados de México que incluyen a Veracruz, Querétaro, el Estado de México y la Ciudad de México. Dos muestras de suero de búfalas de agua y una muestra de suero de una gama fueron positivas al virus de la diarrea viral bovina mediante reacción en cadena de la polimerasa con transcripción reversa. El análisis filogenético de las secuencias amplificadas las agrupó dentro del subgenotipo 1b del virus de la diarrea viral bovina. Además, se logró el aislamiento de un virus citopático a partir de la muestra de suero de la gama. Este estudio constituye el primer reporte del virus de la diarrea viral bovina en artiodáctilos silvestres en México.

The causes of bovine respiratory disease complex (BRDC) are multifactorial and include infection with both viral and bacterial pathogens. Host factors are also involved as different breeds of cattle appear to have different susceptibilities to BRDC. Infection with bovine pestiviruses, including bovine viral diarrhea virus 1 (BVDV1), BVDV2 and 'HoBi'-like viruses, is linked to the development of BRDC. The aim of the present study was to compare the growth of different bovine pestiviruses in primary testicle cell cultures obtained from taurine, indicine and mixed taurine and indicine cattle breeds. Primary cells strains, derived from testicular tissue, were generated from three animals from each breed. Bovine pestivirus strains used were from BVDV-1a, BVDV-1b, BVDV-2a and 'HoBi'-like virus. Growth was compared by determining virus titers after one passage in primary cells. All tests were run in triplicate. Virus titers were determined by endpoint dilution and RT-qPCR. Statistical analysis was performed using one way analysis of variance (ANOVA) followed by the Tukey's Multiple Comparison Test (P˂0.05). Significant differences in virus growth did not correlate with cattle breed. However, significant differences were observed between cells derived from different individuals regardless of breed. Variation in the replication of virus in primary cell strains may reflect a genetic predisposition that favors virus replication.