A real-time reverse transcriptase polymerase chain reaction for detection and quantification of Vesiculovirus

Vesiculoviruses (VSV) are zoonotic viruses that cause vesicular stomatitis disease in cattle, horses and pigs, as well as sporadic human cases of acute febrile illness. Therefore, diagnosis of VSV infections by reliable laboratory techniques is important to allow a proper case management and implementation of strategies for the containment of virus spread. We show here a sensitive and reproducible real-time reverse transcriptase polymerase chain reaction (RT-PCR) for detection and quantification of VSV. The assay was evaluated with arthropods and serum samples obtained from horses, cattle and patients with acute febrile disease. The real-time RT-PCR amplified the Piry, Carajas, Alagoas and Indiana Vesiculovirus at a melting temperature 81.02 ± 0.8ºC, and the sensitivity of assay was estimated in 10 RNA copies/mL to the Piry Vesiculovirus. The viral genome has been detected in samples of horses and cattle, but not detected in human sera or arthropods. Thus, this assay allows a preliminary differential diagnosis of VSV infections.

Viral contamination during sequential phacoemulsification surgeries in an experimental model / Contaminação viral durante cirurgias sequenciais de facoemulsificação em um modelo experimental

PURPOSE: To determine the incidence of Piry virus contamination among surgical instruments used with disposable accessories for phacoemulsification during sequential surgeries. METHODS: An experimental model was created with 4 pigs' eyes that were contaminated with Piry virus and 4 pigs' eyes that were not contaminated. Phacoemulsification was performed on the eyes, alternating between the contaminated and non-contaminated eyes. From one surgery to another, the operating fields, gloves, scalpel, tweezers, needles, syringes, tips and bag collector from the phacoemulsification machine were exchanged; only the hand piece and the irrigation and aspiration systems were maintained. RESULTS: In the collector bag, three samples from the contaminated eyes (3/4) were positive, and two samples from the non-contaminated (2/4) eyes were also positive; at the tip, one sample from the contaminated eyes (1/4) and two samples of the non-contaminated eyes (2/4) yielded positive results. In the irrigation system, one sample from a non-contaminated eye (1/4) was positive, and in the aspiration system, two samples from contaminated eyes (2/4) and two samples from non-contaminated eyes (2/4) were positive. In the gloves, the samples were positive in two samples from the non-contaminated eyes (2/4) and in two samples from the contaminated eyes (2/4). In the scalpel samples, three contaminated eyes (3/4) and none of the non-contaminated eyes (0/4) were positive; finally, two samples from the anterior chambers of the non-contaminated eyes gathered after surgery were positive. CONCLUSIONS: In two non-contaminated eyes, the presence of genetic material was detected after phacoemulsification surgery, demonstrating that the transmission of the genetic material of the Piry virus occurred at some point during the surgery on these non-contaminated eyes when the hand piece and irrigation and aspiration systems were reused between surgeries.

OBJETIVO: Determinar a incidência de contaminação com o vírus Piry entre os instrumentos cirúrgicos e acessórios usados durante cirurgias sequenciais de facoemulsificação. MÉTODOS: Um modelo experimental foi realizado com quatro olhos de porcos que foram contaminados com o vírus Piry e quatro olhos de porcos não contaminados. A facoemulsificação foi realizada alternando um olho contaminado para outro olho não contaminado. Entre as cirurgias, os campos de operação, luvas, bisturi, pinças, agulhas, seringas, pontas e bolsa coletora foram trocados, mantendo somente a caneta e os sistemas de irrigação e aspiração do facoemulsificador. RESULTADOS: No saco coletor, três amostras de olhos contaminados (3/4) foram positivos, e duas amostras de olhos não contaminados (2/4) também foram positivos; na ponta do facoemulsificador, uma amostra dos olhos contaminados (1/4) e duas amostras de olhos não contaminados (2/4) apresentaram resultados positivos. No sistema de irrigação, uma amostra de um olho não contaminado (1/4) foi positivo, e no sistema de aspiração, duas amostras de olhos contaminados (2/4) e duas amostras de olhos não contaminados (2/4) foram positivos. Nas luvas, as amostras foram positivos em dois olhos não contaminados (2/4) e duas amostras de olhos contaminados (2/4). Nas amostras de bisturi, três olhos contaminados (3/4) e nenhum dos olhos não contaminados (0/4) foram positivos e, finalmente, duas amostras da câmara anterior dos olhos não contaminados (2/4) reunidos após a cirurgia foram positivos. CONCLUSÕES: Em dois olhos não contaminados, a presença de material genético foi detectado após a cirurgia de facoemulsificação, demonstrando que a transmissão do material genético do vírus Piry ocorreu em algum ponto durante a cirurgia para estes olhos não contaminados, quando a caneta de facoemulsificação e o sistema de irrigação e aspiração foram reutilizados entre as cirurgias.

Chandipura virus encephalitis outbreak among children in Nagpur division, Maharashtra, 2007.

Background & objectives: An outbreak of acute encephalitis syndrome (AES) among children from Nagpur division, Maharashtra was investigated to confirm the aetiology and to describe clinico-epidemiological features. Methods: AES cases among children <15 yr, from Nagpur division, hospitalized between June-September 2007, were investigated. Serum and cerebrospinal fluid (CSF) were tested for IgM antibodies against Chandipura virus (CHPV) and Japanese encephalitis virus (JEV) and for CHPV RNA by RT-PCR. Partial N gene sequences were used for phylogenetic analysis. Virus isolations were attempted in rhabdomyosarcoma (RD) cell line. Sandflies were collected, pooled and tested for CHPV RNA by RT-PCR. Results: A total of 78 AES cases were recorded in children <15 yr of age. Case fatality ratio was 43.6 per cent. Male to female ratio was 1:1.2. Chandipura (CHP) was confirmed in 39 cases. CHPV RNA was detected in both CSF and serum specimens of 2 cases and in serum of 22 cases. Phylogenetic analysis showed 99.98 – 100 per cent nucleotide identity in the sequences studied. Anti-CHPV IgM antibodies were detected in CSF of 2 cases and in serum of 8 cases. Seroconversion to anti-CHPV IgM antibodies was observed in 5 cases. Clinical manifestations of CHP cases (n=38) were fever (100%), convulsion (76.3%), altered sensorium (34.2%), headache (23.7%), vomiting (44.7%) and diarrhoea (23.7%). CHPV RNA was detected in one of two pools of sandflies from affected locality. Interpretation & conclusions: Chandipura virus was confirmed as the aetiological agent of this acute encephalitis outbreak with high case-fatality among children.

Diagnosis of Brazilian vesiculoviruses by reverse transcription-polymerase chain reaction

We describe a reverse transcription-polymerase chain reaction (RT-PCR) and a nested-PCR for diagnosis of Piry, Carajás, Cocal, and Alagoas vesiculoviruses from Brazil. The RNA extracts of viral and clinical samples were submitted to a RT-PCR using Vesiculovirus G primers that amplify part of the glycoprotein gene. The RT-PCR produced amplicons of expected size, 290 base pair, for the four studied viruses. The RT-PCR showed a high sensitivity being 151.3 times (2.18 log) more sensitive for the detection of Piry virus than the classical procedure for virus detection in tissue culture based on the viral cytophatic effect. Amplicons had nucleotides sequenced and were aligned in order to select internal primers for a nested-PCR to confirm the origin of Piry, Carajás, Cocal, and Alagoas Vesiculovirus. Ten blood and tarsal pad epithelial samples of infected Guinea-pigs had Vesiculovirus genome amplified by RT-nested-PCR.