Outbreak of cholera in a remote village in western India

Background & objectives: Atypical El Tor strains of Vibrio cholerae are frequently implicated in outbreaks of cholera. It is important to understand genetic variations of such strains which impact clinical and epidemiological outcomes. The present study was carried out to characterize an outbreak of cholera which occurred between July 8 and 13, 2018, in a remote settlement in Nashik district, Maharashtra. Methods: A large number of acute diarrhoea cases were reported in Rahude village, Nashik, Maharashtra since July 8, 2018. Molecular characterization of the isolated strains of V. cholerae was done. Results: 195 cases of cholera were detected from a population of 850 (attack rate 22.9%) with two deaths (Case Fatality Ratio of 1.03). A non-haemolytic polymyxin B sensitive strain of V. cholerae O1 Ogawa was isolated from 5/14 fecal samples. Molecular characterization of the isolates indicated that this strain was an altered El Tor (AET) strain. Deletion of the trinucleotide ‘GTA’ in the rstB gene, a unique feature of classical strains, was observed. Interpretation & conclusions: A cholera outbreak caused by a non-haemolytic polymixin B sensitive AET strain, occurred from July 8 to 13, 2018, in a remote settlement in western India. The molecular characterization of the outbreak strains highlighted an assortment of genetic determinants, stressing the need to monitor the genetic attributes of V. cholerae O1 in outbreaks for better understanding and mapping of clinical and epidemiological changes.

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.

Detection of Mycoplasma species in cell culture by PCR and RFLP based method: effect of BM-cyclin to cure infections.

PURPOSE: A two-stage nested polymerase chain reaction (PCR) assay system was described that amplifies the 16S-23S rRNA spacer region sequences of Mycoplasma and Acholeplasma infections in cell cultures and virus stocks. METHODS: Established cell lines and virus stocks were screened for the presence of Mycoplasma by using nested PCR using two sets of outer and inner primers, amplifies 16S-23S rRNA. PCR and restriction fragment length polymorphism (RFLP) assay was used to detect and identify most of the species-specific Mycoplasmas involved in cell cultures and virus stock contaminants. Infected cultures detected by PCR-RFLP were further treated with BM-cyclin (5 microg/mL) and passaged for three times and tested for Mycoplasma infections by PCR-RFLP. RESULTS: Mycoplasma pirum and Mycoplasma orale infections were detected by nested PCR. Species specificity was identified by using RFLP of Vsp I, Cla I and Hin dIII restriction enzymes. Mycoplasma infections were cured by treatment with BM-cyclin. This was further confirmed by non-amplification of PCR amplimers in BM-cyclin treated vs. non-treated cultures. CONCLUSIONS: Regular monitoring of cell cultures for Mycoplasma infections and identification of species-specific Mollicutes will identify the source of contaminations. This approach can be used for quality control of the biological reagents used in cell culture and virology laboratories.

Hepatitis G virus (HGV) infection & its pathogenic significance in patients of cirrhosis.

In the present study the hepatitis G virus (HGV) infection and its pathogenic significance in patients of cirrhosis were assessed using reverse transcription plus nested polymerase chain reaction (RT-PCR). Serum samples were collected from a total of 50 patients of histologically proven non-alcoholic cirrhosis and from a control group consisting of 50 healthy voluntary blood donors. HGV RNA was detected by RT-PCR using primer sequences located in the conserved NS3 helicase region of HGV genome. Serological evaluation for markers of chronic infection with HBV (HBsAg, IgG anti-HBc, HBeAg) and HCV (anti-HCV) was carried out using commercially available kits. HBV DNA and HCV RNA were also tested by PCR in those samples that were found to be non-B, non-C by serological assays. Serological evidence of exposure to HBV was found in 31 (62%) and to HCV in 15 (30%) patients. HGV RNA was detected in 6 (12%) cirrhosis patients and in 2 (4%) healthy blood donors but the difference between the two groups was not statistically significant. Of the 6 HGV positive patients, 2 were coinfected with HBV, 1 with HCV, while the remaining 3 belonged to non-B, non-C category. No significant difference was observed in the clinical and biochemical profiles of HGV-positive and HGV-negative patients except that a history of blood transfusion was significantly (P < 0.005) more common in the former. The findings indicate that the HGV infection is commonly observed in both cirrhosis patients as well as healthy blood donors. A significant association of the virus with blood transfusion is indicative of a parenteral route of transmission. The observations of this study also suggest that the pathogenic role of HGV in the causation of liver disease may be insignificant.