Antiviral activity of the Indian medicinal plant extract Swertia chirata against herpes simplex viruses: a study by in-vitro and molecular approach.

PURPOSE: The antiviral activity of Indian Medicinal plant extract Swertia chirata was tested against Herpes simplex virus (HSV) type-1, using multiple approaches both at cellular and molecular level. METHODS: Cytotoxicity, plaque reduction, virus infectivity, antigen expression and polymerase chain reaction (PCR) assays were conducted to test the antiviral activity of the plant extract. RESULTS: Swertia plant crude extract (1 gm/mL) at 1:64 dilution inhibited HSV-1, plaque formation at more than 70% level. HSV antigen expression and time kinetics experiments conducted by indirect immunofluorescence (IFA) test, revealed a characteristic pattern of small foci of single fluorescent cells in Swertia extract treated HSV-1 infected cells at 4 hours post infection dose, suggested drug inhibited viral dissemination. Infected cell cultures treated with Swertia extract at various time intervals, tested by PCR, failed to show amplification at 12, 24-72 hours. HSV-1 infected cells treated with Acyclovir (antiviral drug) did not show any amplification by PCR. CONCLUSIONS: In this preliminary study, the Indian medicinal plant extract, Swertia chirata showed antiviral properties against Herpes simplex virus type-1.

Does Rota virus infection cause persistent diarrhoea in childhood?

Rota virus is the commonest agent for infectious diarrhoea in childhood. Whether an acute diarrhoea episode due to Rota virus constitutes a risk factor for persistence of diarrhoeal episode has not been well evaluated. This study aimed at evaluating the role of antecedent Rota virus infection in the causation of persistent diarrhoea. One hundred twenty children with acute watery diarrhoea were investigated for evidence of recent Rota virus infection and were followed up for 2 weeks to determine the proportion developing persistent diarrhoea. Rota virus antigen in stool and IgM class antibodies in serum were detected in 33 (27.5%) of the cases, only 2 (6.06%) of whom developed persistent diarrhoea. On the other hand 11.3% children without evidence for antecedent Rota virus infection developed persistent diarrhoea. The prevalence of Rota virus antigen in stools of children who developed persistent diarrhoea was 16.7%. In another group of 25 children with persistent diarrhoea definite evidence for a Rota virus infection was detected in only 2 (8%) cases. It was therefore concluded that antecedent Rota virus infection does not increase the risk for abnormal prolongation of an episode of acute diarrhoea.