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En los sistemas de producción porcina, uno de los puntos críticos que deben ser atendidos con estricto rigor, es la salud de los cerdos. La salud, es un componente estructural del bienestar animal y refleja un estado óptimo de los animales, lo que repercute directamente en un mayor desempeño productivo y mejores condiciones de desarrollo. Uno de los eslabones más frágiles de la salud de los cerdos, es la presencia de enfermedades infecciosas más importantes, las cuales pueden representar pérdidas hasta del 100 % de la producción, por lo cual, debe ser un tema de atención constante, y continuamente vigilado por el Médico Veterinario Zootecnista y los productores, en perfecta coordinación con las autoridades sanitarias oficiales. En la actualidad, la implementación de mejores prácticas en la cadena productiva es de interés para productores y consumidores. El control de las enfermedades infecciosas debe ser un tema de colaboración entre los diferentes actores del entorno y ser considerado un bien público, ya que las repercusiones negativas, pueden ser desde el nivel local hasta mundial. En la presente revisión, se abordará la temática relacionada con las principales enfermedades infecciosas que ponen en riesgo la salud porcina, el impacto, las principales aportaciones realizadas por el Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP) en sus 35 años de vida, específicamente en el Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad (CENID-SAI), anteriormente conocido como el emblemático CENID-Microbiología o Palo Alto.

La importancia de las cabras en México radica en que su producción se concentra en zonas áridas y semiáridas del norte y el centro del país, y particularmente en la región de la Mixteca en los estados de Oaxaca, Guerrero y Puebla, donde prevalece la pobreza y donde la especie, es capaz de sobrevivir y producir leche y cabritos. El estudio de las enfermedades de las cabras en México es escaso; el INIFAP se ha caracterizado por nunca haber dejado de lado la investigación en esta especie. En esta revisión, se abordan las principales enfermedades que afectan a las cabras en México y se describen las investigaciones que sobre ellas ha desarrollado el INIFAP. Los problemas de salud que enfrentan la mayoría de los rebaños caprinos en los que se ha realizado investigación, demuestran que algunos trastornos reproductivos son causados por enfermedades como brucelosis, leptospirosis y clamidiasis, todas éstas consideradas endémicas y con potencial zoonótico. Por otra parte, los problemas de tipo respiratorio y digestivo son los principales padecimientos que afectan a los cabritos. En las cabras en etapa productiva del territorio nacional, se ha demostrado una frecuencia elevada de animales con artritis encefalitis, enfermedad causada por la infección de Lentivirus de los pequeños rumiantes, paratuberculosis y linfadenitis caseosa, estas últimas de origen bacteriano; una particularidad de estas tres enfermedades es su característica de cronicidad, lo que hace pensar de manera equívoca al productor que su presencia no tiene mayor impacto dentro de los rebaños. Finalmente, se ha logrado detectar la presencia de la fiebre Q, una enfermedad zoonotica actualmente considerada exótica en México, y que en otros países es frecuentemente asociada con trastornos reproductivos, abortos y ocasionalmente, problemas respiratorios en los animales. En las aportaciones del INIFAP hay que destacar el diagnóstico y el control de la brucelosis, que es la principal zoonosis bacteriana en nuestro país; además de haber contribuido a que enfermedades consideradas exóticas en México, se determine que ya son endémicas, y se cuente con las herramientas para su diagnóstico, siendo un reto para nuestro instituto realizar la transferencia de estas tecnologías a los laboratorios de diagnóstico de nuestro país.

The SARS-CoV-2 virus is an emerging coronavirus identified in 2019 and is responsible for the disease called COVID-19, which was declared a global pandemic, in 2020 by the World Health Organization (WHO). At the beginning of May 2020, more than 4 million infected people have been confirmed in the world and more than 278 thousand deaths, estimating an economic impact of more than 3 billion dollars. In Mexico, a total of 36,327 positive cases have been confirmed. The impact of this disease is mainly associated with the rapid spread among the human population and the severity of the clinical signs, which, if not treated, can lead to death. Currently, there is no vaccine available to prevent the disease and its control is based on the clinical diagnosis, which must be carried out by a specialist. This diagnosis must be confirmed by laboratory tests, which are of two types, mainly: for the detection of the etiological agent (virological and molecular) and serological (detection of antibodies), both tests must be carried out by institutions approved by the InDRE. The objective of molecular diagnosis (which is the most widely used worldwide) is to identify a fragment of the viral genome, which would indicate that the individual has had exposure and has been infected with SARS-CoV-2. In the case of serological tests, the diagnosis is based on identifying the presence of specific antibodies in serum samples from patients in the convalescent phase, with this test the degree of protection in a population can be evaluated. Both types of tests can be performed in patients with or without symptoms and are of utmost importance for the establishment of prevention and control measures for this pandemic.

In Mexico, the first outbreaks suggestive of the circulation of the porcine epidemic diarrhea virus (PEDV) were identified at the beginning of July 2013. To identify the molecular characteristics of the PEDV Spike (S) gene in Mexico, 116 samples of the intestine and diarrhea of piglets with clinical signs of porcine epidemic diarrhea (PED) were obtained. Samples were collected from 14 farms located in six states of Mexico (Jalisco, Puebla, Sonora, Veracruz, Guanajuato, and Michoacán) from 2013 to 2016. To identify PEDV, we used real-time RT-PCR to discriminate between non-INDEL and INDEL strains. We chose samples according to state and year to characterize the S gene. After amplification of the S gene, the obtained products were sequenced and assembled. The complete amino acid sequences of the spike protein were used to perform an epitope analysis, which was used to determine null mutations in regions SS2, SS6, and 2C10 compared to the sequences of G2. A phylogenetic analysis determined the circulation of G2b and INDEL strains in Mexico. However, several mutations were recorded in the collagenase equivalent (COE) region that were related to the change in polarity and charge of the amino acid residues. The PEDV strain circulating in Jalisco in 2016 has an insertion of three amino acids (232LGL234) and one change in the antigenic site of the COE region, and strains from the years 2015 and 2016 changed the index of the surface probability, which could be related to the re-emergence of disease outbreaks.

Blue eye disease (BED) of pigs was identified in the early 1980s in La Piedad, Michoacan, Mexico. The causal agent is Porcine orthorubulavirus (PRV), which affects pigs of all ages, producing nervous, respiratory, and reproductive disorders. BED is geographically endemic to the center of Mexico, where 75% of the country's swine industry is concentrated. Due to its adverse effects on the swine industry and the risk of dissemination to other countries, it is essential to have reliable diagnostic methods for BED. The objective of this study was to establish the optimal conditions for three serological tests, hemagglutination inhibition (HI), immunoperoxidase monolayer assay (IPMA), and serum neutralization (SN), and to compare their sensitivity, specificity, kappa coefficient, and predictive values. Twelve different HI protocols (9408 tests), one SN protocol and one IPMA protocol (784 tests, each) were evaluated. Forty-nine sera were analyzed, and thirty-seven sera showed true positive results, while twelve showed true negative results. The kappa coefficient was used to assess the variation in each test. The best HI protocol registered a sensitivity and specificity of 89 and 100%, respectively, the IPMA test showed values of 85 and 100%, and the SN test registered a sensitivity of 91% and a specificity of 96%. One of the disadvantages of the HI test is that when chicken red blood cells (RBCs) are used, elution occurs in a short incubation time, which would decrease the specificity. The use of bovine RBCs increases the specificity of the testy and makes it more stable, but it decreases the sensitivity. The results of HI and SN revealed the importance of eliminating the complement system of the serum and removing other inhibitors to avoid test nonspecificity. The IPMA test does not use an active virus; hence, it is considered safe and does not present any risk of disseminating PRV.

Small ruminant lentiviruses (SRLVs) are one of the main viral agents affecting goats worldwide. They cause a systemic, chronic, incurable, degenerative disease. In Mexico, the B1 genotype of SRLV has been detected as endemic in goats and sheep; however, its pathological characteristics have not yet been evaluated. In this study, sampling was performed to identify the percentage of SRLV positivity in different farms in Mexico. Prevalence rates of 19.6 % and 11.6 % were detected through PCR and serology, respectively. Through a real-time PCR differential test, the prevalence of genotype B was identified. From a chosen case, an SRLV strain was isolated (which was called SRLV/B1/Goat/Mx/INIFAP-1/2013). The phylogenetic analysis revealed that the strain SRLV/B1/Goat/Mx/INIFAP-1/2013 shares a great homology with an American and Asiatic strains of the B1 genotype. Virulence of the isolated strain was analyzed during an experimental infection in kids. The kids did not present clinical disease after the experimental infection. The high viral load values persisted throughout the entire experiment (90 days), and no seroconversion was detected. At necropsy, macroscopic alterations were not observed, except in the lungs. The microscopic lesions in the respiratory tract consisted of moderate interstitial pneumonia, peribronchial lymphoid hyperplasia, and bronchial exudate. In the central nervous system, moderate gliosis, meningeal congestion, lymphocyte infiltration, satellitosis, and demyelination were observed. The virus was systemically distributed among organs; the cerebellum and carpal synovial fluid samples were those with the highest viral load, 5.73 copies of virus per ng of total DNA (log10) and 5.07 log10, respectively. In this study, we identified a strain with high homology to Asiatic strains that manifested low virulence in kids during short infection. Understanding the strains that circulate in the goat population will allow implementing better diagnostic methodologies to propose disease control alternatives for this emerging animal production system in Mexico.

The objective of this study was to evaluate the clinical disease, humoral response and viral distribution of recent Porcine rubulavirus (PorPV) isolates in experimentally infected pigs. Four, 6-piglet (5-days old) groups were employed (G1-84, G2-93, G3-147, and G4-T). Three viral strains were used for the experimental infection: the reference strain LPMV-1984 (Michoacan 1984) and two other strains isolated in 2013, one in Queretaro (Qro/93/2013) and the other in Michoacan (Mich/147/2013). Each strain was genetically characterized by amplification and sequencing of the gene encoding hemagglutinin-neuroamidase (HN). The inoculation was performed through the oronasal and ocular routes, at a dose of 1 × 10 6 TCID 50 /ml. Subsequently, the signs were evaluated daily and necropsies were performed on 3 different days post infection (dpi). We recorded all micro- and macroscopic lesions. Organs from the nervous, lymphatic, and respiratory system were analyzed by quantifying the viral RNA load and the presence of the infectious virus. The presence of the viral antigen in organs was evidenced through immunohistochemistry. Seroconversion was evaluated through the use of a hemagglutination inhibition test. In the characterization of gene HN, only three substitutions were identified in strain Mich/147/2013, two in strain LPMV/1984 (fourth passage) and one in strain Qro/93/2013, with respect to reference strain LPMV-84, these changes had not been identified as virulence factors in previously reported strains. Neurological alterations associated with the infection were found in all three experimental groups starting from 3 dpi. Groups G1-84 and G3-147 presented the most exacerbated nervous signs. Group G2-93 only presented milder signs including slight motor incoordination, and an increased rectal temperature starting from day 5 post infection (PI). The main histopathological findings were the presence of a mononuclear inflammatory infiltrate (lymphocytic/monocytic) surrounding the ventricles in the brain and focal interstitial pneumonitis with distention of the alveolar sacs in the lungs. PorPV and RNA distribution were identified in the organs of the nervous, lymphatic, and respiratory systems of the piglets analyzed at different times (days 5, 10, and 15 PI). The viral antigen was detected in the brain and lungs in most of the assessed groups. Seroconversion was evident in groups G1-84 and G2-93. Groups G1-84 and G3-147 were the most clinically affected by the experimental infection. Both strains were isolated in the state of Michoacan. The virulence of the new isolates maintains similar characteristics to those reported more than 30 years ago.