Viral burden and diversity in acute respiratory tract infections in hospitalized children in wet and dry zones of Sri Lanka.

The present study was done to identify the viral diversity, seasonality and burden associated with childhood acute respiratory tract infection (ARTI) in Sri Lanka. Nasopharyngeal aspirates (NPA) of hospitalized children (1 month-5 years) with ARTI were collected in 2 centers (wet and dry zones) from March 2013 to August 2014. Respiratory viral antigen detection by immunofluorescence assay (IFA) was used to identify the infecting viruses. IFA negative 100 NPA samples were tested for human metapeumovirus (hMPV), human bocavirus and corona viruses by polymerase chain reaction. Of the 443 and 418 NPAs, 37.2% and 39.4% were positive for any of the 8 different respiratory viruses tested from two centers studied. Viral co-infection was detected with respiratory syncytial virus (RSV) in both centers. Peak viral detection was noted in the wet zone from May-July 2013 and 2014 and in the dry zone from December-January 2014 suggesting a local seasonality for viral ARTI. RSV showed a clear seasonality with a direct correlation of monthly RSV infections with rainy days in the wet zone and an inverse correlation with temperature in both centers. The case fatality rate was 2.7% for RSV associated ARTI. The overall disability adjusted life years was 335.9 and for RSV associated ARTI it was 241.8. RSV was the commonly detected respiratory virus with an annual seasonality and distribution in rainy seasons in the dry and wet zones of Sri Lanka. Identifying the virus and seasonality will contribute to employ preventive measures and reduce the empirical use of antibiotics in resource limited settings.

Immune response to hepatitis B vaccine in a group of health care workers in Sri Lanka.

Health care workers (HCWs) are considered at high risk of acquiring the hepatitis B virus (HBV). Seroconversion rates after vaccination against HBV among HCWs have not previously been available in Sri Lanka. In the current study, the response to HBV surface antigen (HBsAg) vaccine was assessed in a selected group of HCWs by testing for antibodies against HBsAg (anti-HBs). This was a retrospective descriptive study to measure the anti-HBs levels, using an ELISA, in an immunized group of HCW referred to Department of Microbiology, Faculty of Medicine, University of Peradeniya, Sri Lanka. Among the 342 participants, 9.9% (n=34) were non-responders. Female participants had a significantly higher immune response (94.7%) than males (p<0.05). The results of the study found no significant decline in the immune response with time (p > 0.05). Post HBsAg vaccination immunity in HCW in Sri Lanka is similar to that of global rates with similar gender variation. Anti-HBs levels should be tested in all HCW following HBsAg vaccination so that necessary precautions can be taken.

Susceptibility of New Entrant University students in Sri Lanka to varicella zoster infection.

To investigate the susceptibility of Sri Lankan new entry university students to varicella zoster virus (VZV) infection, a cross-sectional descriptive study was carried out among new entrant medical and engineering students of the University of Peradeniya, Sri Lanka. Self-reported history of chicken pox was studied first, followed by serological evaluation for VZV IgG antibodies. A total of 451 students participated in the study out of which 189 (41.9%) reported a history of chicken pox. Median age of reported age of acquiring the disease was 14 years with an interquartile range of 10 to 17 years. Only 25% of the population reported history of infection prior to age of 10 years. The seropositive rate of VZV IgG antibodies among undergraduates with a negative history of chicken pox was 10.1% ( 25/247). The present study indicates that nearly half (222/436) of the study population (50.9%, 95% CI 46.2-55.6) was susceptible to VZV infection.