Until July 30th, 2019 when the first case of African swine fever (ASF) was confirmed, Serbia was a country free from ASF. After the owner reported atypical illness and death of a sow, the local veterinarian submitted the organ samples to the National Reference Laboratory for Classical Swine Fever (CSF) and African Swine Fever within the Institute of Veterinary Medicine of Serbia in Belgrade. Observed gross lesions included splenomegaly, serous edema of the wall of the gallbladder and hemorrhages in the enlarged portal lymph nodes, petechial hemorrhages on the kidney and epicardium, and petechial and echymotic hemorrhages on the mucosa of the urinary bladder. Results of real-time PCR confirmed that the cause of illness and death of the swine was African swine fever virus. The samples were sent for confirmation to the EU Reference Laboratory where it was confirmed that Serbian domestic pig virus isolates based on p72 belong to genotype II. In total, 270 pigs from 18 affected holdings were killed in the infected zones. According to the on-record data, mortality was 6.89%, whereas lethality reached 64.5%. Currently, an extensive surveillance program is being conducted, aiming to force passive surveillance. ASF in wild boar has not been confirmed so far.
Aim of this study was the retrospective investigation of viral (porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), torque teno sus virus type 1 and 2 (TTSuV1, TTSuV2)) and bacterial (Bordetella bronchiseptica (B. b.), Mycoplasma hyopneumoniae (M. h.), and Pasteurella multocida (P. m.)) co-infections in 110 Pneumocystis spp. positive lung samples of Austrian pigs with pneumonia. Fifty-one % were positive for PCV2, 7% for PRRSV, 22% for TTSuV1, 48% for TTSuV2, 6% for B. b., 29% for M. h., and 21% for P. m. In 38.2% only viral, in 3.6% only bacterial and in 40.0% both, viral and bacterial pathogens were detected. In 29.1% of the cases a co-infection with 1 pathogen, in 28.2% with 2, in 17.3% with 3, and in 7.3% with 4 different infectious agents were observed. The exposure to Pneumocystis significantly decreased the risk of a co-infection with PRRSV in weaning piglets; all other odds ratios were not significant. Four categories of results were compared: I = P. spp. + only viral co-infectants, II = P. spp. + both viral and bacterial co-infectants, III = P. spp. + only bacterial co-infectants, and IV = P. spp. single infection. The evaluation of all samples and the age class of the weaning piglets resulted in a predomination of the categories I and II. In contrast, the suckling piglets showed more samples of category I and IV. In the group of fattening pigs, category II predominated. Suckling piglets can be infected with P. spp. early in life. With increasing age this single infections can be complicated by co-infections with other respiratory diseases.
Porcine circovirus type 2 (PCV2) is the main causative agent of postweaning multisystemic wasting syndrome (PMWS). To characterize and determine the genetic diversity of PCV2 in the porcine population of Serbia, nucleotide and deduced amino acid sequences of the open reading frame 2 (ORF2) of PCV2 collected from the tissues of pigs that either had died as a result of PMWS or did not exhibit disease symptoms were analyzed. Sequencing and phylogenetic analysis showed considerable diversity among PCV2 ORF2 sequences and the existence of two main PCV2 genotypes, PCV2b and PCV2a, with at least three clusters, 1A/B, 1C and 2D. In order to provide further proof that the 1C strain is circulating in the porcine population, the whole viral genome of one PCV2 isolate was sequenced. Genotyping and phylogenetic analysis using the entire viral genome sequences confirmed that there was a PMWS-associated 1C strain emerging in Serbia. Our analysis also showed that PCV2b is dominant in the porcine population, and that it is exclusively associated with PMWS occurrences in the country. These data constitute a useful basis for further epidemiological studies regarding the heterogeneity of PCV2 strains on the European continent.
Porcine circovirus type 2 (PCV2) and hepatitis E virus (HEV) are the most recently recognized causes of infectious hepatitis of pigs and may or may not act independently in the development of the disease. Recently it has been suggested that swine torque teno viruses (TTVs), in co-infections with some swine viral pathogens, may potentiate the severity of disease. In order to search for virological cofactors associated with infectious hepatitis in pigs, we investigated the liver tissues, to determine the presence of TTVs, PCV2 and HEV of naturally infected pigs and analysed the prevalence of both genogroups of the TTVs in the hepatitis lesions. Histopathological techniques, nested-polymerase chain reactions (nPCRs), polymerase chain reaction (PCR) and one-step reverse transcriptase polymerase chain reaction (RT-PCR) were applied to detect hepatitis lesions, TTVs genogroups 1 and 2, PCV2 and HEV infection. Of the livers examined 58% (29/50) had mild to moderate hepatitis and 74% (37/50), 56% (28/50) and 26% (13/50) samples were nPCR, PCR and RT-PCR positive for TTVs PCV2 and HEV respectively. TTVs were detected in 84% (16/19) of the samples which were determined to be of mild severity while present in almost all (90% or 9/10) samples identified as having moderate hepatitis lesions. Additionally, the livers of 12 out of 21 (57%) pigs without the hepatitis lesions were positive for TTVs. These results demonstrate an association between TTVs and infectious hepatitis of pigs in concomitant infections with PCV2 and/or HEV and indicated that TTVs may play a role as a cofactor in the pathogenesis of disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.