Detection of the VP6 gene of group F and G rotaviruses in broiler chicken fecal samples from the Amazon region of Brazil.

The aim of this study was to detect rotavirus F (RVF) and rotavirus G (RVG) in fecal specimens of broiler chickens in Brazil. During 2008 and 2011, a total of 85 fecal samples were collected. The viral genome was extracted, followed by polyacrylamide gel electrophoresis (PAGE), reverse transcription polymerase chain reaction (RT-PCR), and nucleotide sequencing. Samples were screened for rotaviruses by PAGE, and RVF and RVG genome banding patterns were not seen. Using RT-PCR, it was found that 9.4 % (8/85) of the pools contained RVF, whereas 10.6 % (9/85) contained RVG. The predicted amino acid sequences of RVF and RVG from Brazilian samples were 94.4-95.7 % and 96.8-96.9 % identical, respectively, to those of prototypes from Germany. The detection of RVF and RVG in this study provides important epidemiological data about the simultaneous circulation of rotaviruses affecting broiler flocks in the Amazon region of Brazil.

Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil.

BACKGROUND: Foot-and-mouth disease (FMD) is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA) are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed. RESULTS: A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay with high sensitivity and specificity under laboratorial and experimental conditions was used in the current study. To verify the applicability of this assay under field conditions in Brazil, 460 oral swabs from cattle were collected in areas free of FMD (n = 200) and from areas with outbreaks of FMD (n = 260). Three samples from areas with outbreaks of FMD were positive by real-time RT-PCR, and 2 of those samples were positive by virus isolation and ELISA. Four other samples were considered inconclusive by real-time RT-PCR (threshold cycle [Ct] > 40); whereas all 200 samples from an area free of FMD were real-time RT-PCR negative. CONCLUSION: real-time RT-PCR is a powerful technique for reliable detection of FMDV in a fraction of the time required for virus isolation and ELISA. However, it is noteworthy that lack of infrastructure in certain areas with high risk of FMD may be a limiting factor for using real-time RT-PCR as a routine diagnostic tool.