Porcine deltacoronavirus has caused great economic losses in the swine industry worldwide. In this study, we carried out the first detection, sequencing and characterization of this virus in Mexico. We analysed 885 rectal samples by multiplex RT‐PCR to determine coinfections. In addition, the Spike gene was amplified, sequenced and analysed phylogenetically. We found 85 positive samples for porcine deltacoronavirus, representing 9.6% of the total samples, and we determined that the most frequent coinfection was with porcine epidemic diarrhoea virus (54.1%). Four sequences of Mexican isolates were most closely related to those of the United States. The antigenic regions and the glycosylation site of the strains obtained coincide with those previously reported. This relationship is probably related to the commercial exchange of pigs between the US and Mexico and the geographical proximity of these two countries.

Background: The use of biomaterials has been expanded to improve the characteristics of vaccines. Recently we have identified that the peptide PH (1-110) from polyhedrin self-aggregates and incorporates foreign proteins to form particles. We have proposed that this peptide can be used as an antigen carrying system for vaccines. However, the immune response generated by the antigen fused to the peptide has not been fully characterized. In addition, the adjuvant effect and thermostability of the particles has not been evaluated.Results: In the present study we demonstrate the use of a system developed to generate nano and microparticles carrying as a fusion protein peptides or proteins of interest to be used as vaccines. These particles are purified easily by centrifugation. Immunization of animals with the particles in the absence of adjuvant result in a robust and long-lasting immune response. Proteins contained inside the particles are maintained for over 1 year at ambient temperature, preserving their immunological properties. Conclusion:The rapid and efficient production of the particles in addition to the robust immune response they generate position this system as an excellent method for the rapid response against emerging diseases. The thermostability conferred by the particle system facilitates the distribution of the vaccines in developing countries or areas with no electricity.

This is a first report in Mexico of the presence of antibodies against respiratory syncytial virus (RSV) and parainfluenza-3 virus in Mexican sheep in different productive stages. We determine the association of serological positivity with age and production system, and obtain molecular evidence of infection by both virus. RSV prevalence in adult sheep was 47% (49/105) at the tropic and 64% (63/99) at the uplands. A significant difference in RSV seropositivity between animals from the tropic and the uplands was observed (P \ 0.05). Seropositivity correlated with production system (P = 0.003, OR = 2.042), with a risk of showing antibodies was 2.042 times higher in sheep under an extensive production system. A significant difference in PI3V seropositivity between animals from either provenance (P = 0.017, OR = 0.475) were also found, with a risk of showing antibodies 0.475 times higher in sheep under an extensive production system. Genetic material from RSV and PI3V was identified by RT-PCR in nasal swab samples from clinically healthy lambs and confirmed by sequencing and phylogenetic analysis. Serological results show that sheep are susceptible to infection by both viruses, and molecular results suggest that the identified antibodies are result of natural infections and reinfections.

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We sampled sera from 1013 non-vaccinated swine from four states in Mexico, Guanajuato, Jalisco, Michoacán and the Estado de Mexico, to analyse anti-porcine rubulavirus antibody titres against three different porcine rubulavirus isolates (PAC-4/1993, PAC-6/2001, and PAC-9/2003) using a hemagglutination inhibition assay. The results revealed that there were antigenic differences among the isolates assessed. In particular, the estimated correlation between the PAC-4/1993 and PAC-6/2001 (0.50) isolates and between the PAC-4/1993 and PAC-9/2003 isolates (0.56) displayed a moderate positive correlation. In contrast, there was a strong positive correlation between the PAC-6/2001 and PAC-9/2003 isolates (0.73). We also found that in the state of Guanajuato, PAC-4/1993 was the isolate that was most frequently identified; in Jalisco, the isolate was PAC-6/2001; and in Michoacán, the isolate was PAC-9/2003. By contrast, in the Estado de Mexico, all three isolates appeared to circulate with a low seroprevalence. In general, the analysed sera from the four states displayed a porcine rubulavirus serological prevalence ranging from 9% to 23.7%. These data indicate that there is not complete antibody cross-antigenicity among the three isolates, and the antigenic variations in the antibody response found in this study implies that the use of a monovalent vaccine would not generate complete protection against the different antigenic subtypes.