PCV3-associated reproductive failure in pig herds in Brazil.

Porcine circovirus type 3 (PCV3) has been widely detected worldwide in healthy and sick pigs. Recently its association with clinical disease and reproductive failure has been proven through the detection of intralesional viral mRNA in affected pigs. This study aims to describe the occurrence of PCV3-associated reproductive failure (abortions) in sow herds in southern Brazil. Eleven fetuses from five different litters from two herds were analyzed. These herds reported an increase in the rate of late-gestation abortions, stillbirths, and the percentage of mummified piglets. At gross examination, six of the fetuses had large caudally rotated ears and one fetus was mummified. Microscopically, multisystemic vasculitis, lymphocytic interstitial pneumonia, myocarditis, and encephalitis were observed. These six fetuses with gross and histological lesions were positive in qPCR analysis for PCV3, and PCV3 transcription was shown through in situ hybridization (ISH-RNA) within the histologic lesions. Samples from all 11 fetuses tested negative in PCR exam for Porcine Circovirus type 1 and 2, Porcine Reproductive and Respiratory Syndrome, Porcine Parvovirus, and Atypical Porcine Pestivirus. Furthermore, based on the ORF2 analysis, the PCV3a clade was identified. This is the first report of PCV3a-associated reproductive failure in pig herds in South America.

A putative PCV3-associated disease in piglets from Southern Brazil.

Porcine circovirus type 3 (PCV3) is widely distributed worldwide, and its association with clinical disease in pigs has been studied in recent years. This study describes a novel PCV3-associated clinical disease in piglets from Brazil. Since September 2020, we received 48 piglets with large caudally rotated ears, weakness, and dyspnea. Most piglets were from gilts and died 1-5 days after birth. Two piglets that presented similar clinical signs and survived until 35-60 days had a marked decrease in growth rate. At post-mortem examination, the lungs did not collapse due to marked interlobular edema. Microscopically, the main feature was multisystemic vasculitis characterized by lymphocytes and plasma cells infiltrating and disrupting the wall of vessels, lymphohistiocytic interstitial pneumonia, myocarditis, and encephalitis. Viral replication was confirmed in these lesions through in situ hybridization (ISH-RNA). Seventeen cases were positive for PCV3 in PCR analysis, and all samples tested negative for porcine circovirus (PCV1, and PCV2); porcine parvovirus (PPV1, 2, 5, and 6); atypical porcine pestivirus (APPV); porcine reproductive and respiratory syndrome (PRRSV); and ovine herpesvirus-2 (OvHV-2). Phylogenetic analysis of the ORF2 sequence from five different pig farms showed that the PCV3a clade is circulating among Brazil's swineherds and causing neonatal piglet losses. This is the first report of PCV3a-associated disease in neonatal pigs from farms in Brazil.

Swine polioencephalomyelitis in Brazil: identification of Teschovirus A, Sapelovirus A, and Enterovirus G in a farm from Southern Brazil.

Porcine encephalomyelitis can be associated with many etiologies, including viral agents, such as Porcine teschovirus (PTV), Porcine sapelovirus (PSV), and Porcine astrovirus (PoAstV). In this study, we investigated the presence of these viruses in a neurological disease outbreak in a swine farm in Southern Brazil. The piglet production farm unity had 1200 weaning piglets, and 40 piglets with neurological signs such as motor incoordination, paresis, and paralysis of hind limbs, with an evolution time of approximately 4 days. Among these, 10 piglets were submitted to postmortem examination. Gross lesions were restricted to a mild enlargement of the nerve roots and ganglia of spinal cord segments. The microscopic lesions were characterized by nonsuppurative encephalomyelitis and ganglioneuritis with evident neuronal degeneration and necrosis. Samples of the central nervous system (CNS), cerebrospinal fluid, and feces were collected and submitted to molecular analysis. PTV was identified in all samples of the CNS, while eight of the piglets were also positive for PSV, and seven were positive for Porcine enterovirus (EV-G). PoAstV was identified in a pool of feces of healthy animals used as controls. This study demonstrates the occurrence of encephalomyelitis associated with PTV on a swine farm in Southern Brazil, as well as the presence of other viruses such as PSV, EV-G, and PoAstV in the swineherd. Sequences of the fragments that were previously amplified by PCR showed a high similarity to PTV 6. Herein, we describe the first case report of severe swine polioencephalomyelitis associated with PTV in South America.

Molecular and pathological characterization of teat papillomatosis in dairy cows in southern Brazil.

Teat papillomatosis is caused by different bovine papillomavirus (BPV) types and is especially important for dairy cows, because it results in severe damage to the health and structure of the mammary gland. This work describes the molecular and pathological aspects of teat papillomatosis in dairy cows in southern Brazil. Samples of teat papillomas were collect from 73 slaughtered dairy cows. Fragments of the lesions were collected in individual pools per animal and subjected to PCR using the FAP primer pair and sequencing of the amplification products. Teats with the remaining lesions were fixed in 10% neutral buffered formalin, routinely processed for histopathology, and stained with hematoxylin and eosin (H&E). Papillomatous lesions were characterized by three macroscopic patterns, namely exophytic (5 [6.9%]), flat (29 [39.7%]), and mixed (39 [53.4%]). Histologically, all samples were identified as squamous papillomas. Partial sequencing of the L1 gene resulted in the detection of 8 classical BPV types (BPVs 4, 6, 7, 8, 9, 10, 11, and 12) in 27 samples, 6 previously reported putative BPV types in 17 samples, and 10 putative new BPV types in 15 samples. Four sequences could not be classified, and 10 were negative in the PCR. There was no correlation between the gross pattern and the BPV type identified, and all the samples were characterized by squamous papillomas under histological examination. However, 24 different BPV types were identified, demonstrating high genetic diversity among BPVs associated with teat papillomatosis in dairy cows in southern Brazil.

Detection of enzootic nasal tumor virus (ENTV) in a sheep flock in southern Brazil.

Enzootic nasal tumor (ENT) is a contagious neoplasm associated with enzootic nasal tumor virus (ENTV), which may induce disease in sheep (ENTV-1) and goats (ENTV-2). This study aimed to describe the occurrence of ENT in two Texel sheep (Ovis aries) from a 75-sheep flock, located in the city of Gravataí, southern Brazil. Animals used to be purchased from different origins, and no specific tests for disease monitoring or quarantine procedure were performed. Affected animals presented respiratory distress, anorexia with severe weight loss, and mucopurulent unilateral nasal discharge. Necropsy was performed in both animals and nasal cavity masses were observed. Histopathological analysis demonstrated an epithelial neoplasm compatible with nasal adenocarcinoma. PCR using a protocol that amplifies a 591 bp sequence of 5'LTR-gag region of ENTV1 was performed followed by DNA sequencing. Both samples were positive, and the sequences obtained presented highest identity (97%) with ENTV strain TN28 (GenBank accession number MH899613) detected in a Texel sheep from Scotland. This is the first report of ENTV-1 leading to enzootic nasal tumor in sheep in Latin America, which confirms the presence of the retrovirus in sheep flocks in the Brazilian territory.