Seneca Valley virus induces immunodepressionin suckling piglets by selective apoptosis of B lymphocytes.

Seneca Valley virus (SVV) is the causative agent of an emerging infectious vesicular disease in swine that is clinically indistinguishable from other vesicular diseases of swine. This study utilized healthy suckling piglets (control) and SVV-naturally infected suckling piglets to determine the effects of SVV on lymphoid tissues and determined the SVV RNA load by quantitative RT-PCR (qRT-PCR). Furthermore, immunohistochemistry (IHC) analyses were performed to quantify the expression of T and B cell lymphocytes, natural killer cells, cleaved caspase 3, and ki-67. The main histopathologic finding in the infected group was severe lymphoid depletion. The highest average of SVV RNA load by qRT-PCR (Log10 genomic copies/g of tissue) occurred at the spleen (8.54 ± 0.8), followed by the tonsils (8.04 ± 1.42), and mesenteric lymph nodes (6.90 ± 1.42). The IHC analyses revealed that there was an increased in cellular apoptosis with concomitant reduction in the proliferation of B cells. The results from this study have demonstrated that SVV-infected piglets exhibited decreased lymphocyte density probably due to lymphoid apoptosis, affecting particularly B-cells lymphocytes.

Detection and Quantification of the E6 Oncogene in Bovine Papillomavirus Types 2 and 13 From Urinary Bladder Lesions of Cattle.

Bovine papillomavirus types 2 and 13 can induce tumors in both the cutaneous and mucosal epithelia of cattle. These viral types are associated with the development of benign cutaneous papillomas and malignant lesions in the urinary bladders of cattle, with the latter being known as bovine enzootic hematuria. Among the viral oncoproteins encoded by Deltapapillomavirus DNA, the E6 oncoprotein has an important role in cell proliferation and might be related to cancer initiation and promotion. The aim of this study was to present a standardized SYBR Green-based quantitative PCR for detection and quantification of the bovine papillomavirus 2 and 13 E6 oncogenes in urinary bladder samples from cattle. Twenty-four urinary bladders from cattle displaying tumors (n = 12) and normal bladder mucosa (n = 12) were tested by quantitative PCR. Of the 12 urinary bladders with tumors, six presented bovine papillomavirus 2 DNA concentrations ranging from 1.05 × 104 to 9.53 × 103 copies/µL, while two had bovine papillomavirus 13 DNA amplified at concentrations of 1.30 × 104 to 1.23 × 104 copies/µL. The healthy bladder mucosa samples were negative for both bovine papillomaviruses. Once the results were confirmed by conventional PCR and direct sequencing, the quantitative PCR assay developed in this study was shown to be a sensitive and specific tool for detecting and quantifying the E6 ORF of bovine papillomavirus 2 and 13 in a variety of clinical samples. Our findings of identification of bovine papillomavirus 2 and 13 DNA in urothelial tumors from cattle suffering from bovine enzootic hematuria agree with data from previous studies, representing the first detection of bovine papillomavirus 13 DNA in malignant bladder lesions of cattle from Brazil.

Sanitary program to reduce embryonic mortality associated with infectious diseases in cattle.

Among reproductive disorders in dairy and beef cattle worldwide, embryonic mortalities stand out as one of the most frequent. Because of the multifactorial etiology, the clinical and laboratory diagnoses of embryonic mortality causes in cattle are quite complex. Often, infectious causes may account for up to 50% of bovine embryonic mortality rates after 30 days of conception. This review will address the main causes of early and late embryonic mortality, with emphasis on infectious causes and, particularly, those more frequent in the Brazilian cattle herds. In addition, we will discuss ways of controlling and prophylaxis including those related to reproductive and sanitary management, with emphasis on immunoprophylaxis of the three most frequent reproductive infectious diseases in Brazilian dairy and beef cattle herds.

Development and evaluation of a nested-PCR assay for Senecavirus A diagnosis.

Senecavirus A (SVA) has been associated with vesicular disease in weaned and adult pigs and with high mortality of newborn piglets. This study aimed to establish a nested-PCR assay for the routine diagnosis of SVA infection. Tissue samples (n = 177) were collected from 37 piglets of 18 pig farms located in four different Brazilian states. For the nested-PCR, a primer set was defined to amplify an internal VP1 fragment of 316 bp of SVA genome. Of the 37 piglets, 15 (40.5%) and 23 (62.2%) were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. The SVA RNA was detected in 61/177 (34.5%) samples with the RT-PCR, while the nested-PCR assay showed 84/177 (47.5%) samples with the virus (p < 0.05). According to the herds, 11 (61.1%) and 16 (88.9%) of the 18 pig herds were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. Nucleotide sequencing analysis revealed similarities of 98.7-100% among SVA Brazilian strains and of 86.6-98% with SVA strains from other countries. The nested-PCR assay in this study was suitable to recover the SVA RNA in biological specimens, piglets, and/or herds that were considered as negative in the RT-PCR assay, and is proposed for the routine investigation of the SVA infection in piglets, especially when other techniques are not available or when a great number of samples has to be examined.