Characterization of new strains of Pseudorabies virus in Argentina: Detection of interspecies transmission.

Background: Aujeszky's disease is mainly a swine disease, still endemic worldwide. It can infect other mammalians, including human beings, and it is usually fatal with nervous symptoms. Ever since the disease was detected in 1988 in Argentina, many outbreaks have been reported involving both feral swine and dogs. Aim: At present, in Argentina, Pseudorabies virus (PRV) cases are sporadically reported; however, clinical cases are informed. This study aims to obtain information about the seroprevalence of PRV in wild boars and to isolate and characterize PRV from clinical samples. Methods: From 2018 to 2019, 78 wild boars' serum samples from Bahía de Samborombón natural reserve were analyzed for antibodies to PRV using a virus neutralization test. Clinical samples from 17 pigs, 2 wild boars, 1 dog, and 1 cat were collected from 2013 to 2019 for viral isolation and detection of the presence of the gD gene by PCR. For sequence analysis, the gC partial gene was amplified. Results: Five strains were isolated from the dog, cat, and swine samples. The new PRV strains identified were confirmed by BLAST analysis, which revealed between 99.74% and 100% of similarity to the NIA-3 strain and phylogenetic analysis of the partial gene encoding the gC protein revealed that the PRV strains have divided into two main clades, clade 1 and clade 2. Conclusion: This report informed that most new cases of PRV were detected in the central regions of Argentina, where pig production is concentrated. The study in Bahía de Samborombón revealed a high percentage of detection but, the sampling is not representative of that of the rest of the country. Therefore, a systematic sampling effort of wild boar throughout the country should be included in the national program control. Although in Argentina only the inactivated Bartha vaccine is allowed, recombination risk should not be ignored if attenuated vaccines are incorporated into the National control plan. The two strains, one from the cat and one from the dog sample, are directly related to infected swine. The information about clinical cases and molecular characterization of new strains is important for a better understanding of the dynamics of PRV and to promote preventive measures.

Evidence of porcine circovirus type 2 and co-infection with ungulate protoparvovirus 1 (porcine parvovirus) in mummies and stillborn piglets in subclinically infected farm.

Porcine circovirus type 2 (PCV2) and protoparvovirus 1 (PPV) were detected as single infection (6/131) and (11/131) respectively, or co-infection (6/131) in fetuses and stillborn piglets from normal deliveries in a farm without reproductive problems. Twenty in twenty-three positive samples were over 70 days of gestation, which is when the fetus becomes immunocompetent, and the presence of a NADL-2 PPV strain suggests fetal immune system impairment. Phylogenetic analysis of sequences obtained showed that 8/9 sequences are related to cluster 13 and the remaining is grouped into cluster 11 sequences. An increase in variability in ORF2 sequences in Argentina was observed. It is not clear whether the detection of fetuses positive to PPV and PCV2 is of epidemiological importance in a subclinically affected farm. However, the results of this study showed that currently used vaccines and vaccine protocols do not fully protect against PPV or PCV2 fetus infection.

First isolation and molecular characterization of Suid herpesvirus type 1 from a domestic dog in Argentina.

Since Aujeszky`s disease (pseudorabies), which is caused by Suid herpesvirus type 1 (SuHV-1), was first notified in Argentina in 1978, many SuHV-1 strains have been isolated from swine. However, this disease can affect other vertebrates, such as dogs (secondary hosts), and lead to fatal neurological disease. The objective of the current work is to report the first isolation and molecular characterization of SuHV-1 from a dead domestic dog from Santa Fe Province (Argentina), which had had nervous signs compatible with pseudorabies. Samples of brain and trigeminal ganglia from this dog were obtained and fixed in formol for histopathology, and virology studies were conducted after cell disruption. Supernatants of both samples were inoculated onto RK13 cells and, after 72 h, DNA was extracted with phenol-chloroform. Purified DNA was cut with a restriction enzyme and subjected to agarose gel and an aliquot was used to amplify the gD and gC genes by PCR. The gC sequence was compared with other public sequences. The strain isolated from the dog was similar to other Argentinean swine strains.