Glycoprotein B Genotyping in Congenital/perinatal Cytomegalovirus Infection in Symptomatic Infants.

Background: Molecular epidemiological studies on circulating strains of CMV in cogenital/perinatal infections have not been done earlier in this region. Objective: To study the glycoprotein B genotypes in babies with symptomatic congenital/perinatal CMV infection and to assess the possible influence of genotype on the outcome of the infection. Methods: Clinical samples (blood and urine) of symptomatic babies are sent to the Virology Department of NCDC, Delhi for the diagnosis of congenital infections. 375 clinical samples of infants (newborn - 6 months old) were included for the study. Serum samples were subjected to ELISA for detection of IgM antibodies against CMV. DNA isolation and amplification of CMV genomic DNA targeting gB gene fragment by nested PCR, was carried out in the samples. The amplified fragment including the cleavage site was subjected to RFLP using restriction enzymes Rsal and Hinf1. They were also verified by sequencing using Big Dye Terminator chemistry. Results: 75 samples out of 375 tested were confirmed positive for CMV infection by serology and PCR. Both RFLP and sequencing of gB gene fragment showed that gB 1, 2 and 3 genotypes were in circulation. gB 3 was the most prevalent genotype in symptomatic infants. Hepatosplenomegaly was the most common feature in gB-3 genotype of CMV. gB2 congenital CMV infection was more commonly associated with long term sequelae.

Whole Cell Pertussis Vaccine : Reducing Toxicity.

Since introduction of the pertussis vaccine in 1940’s the morbidity and mortality due to the infection has been markedly reduced all over the world. However the adverse effects of the inactivated whole cell pertussis vaccine like pain, swelling at the site of injection, fever, vomiting anorexia, persistent crying & drowsiness have been the cause of great concern, till date. Also the safety concerns over the use of thiomersal as an inactivating agent as well preservative have been raised in the recent past. Studies in many countries have been initiated to reduce or replace thiomersal & using other inactivating agents in the vaccines. Limited studies have been conducted in India. The present study has been undertaken as an attempt to reduce the quantity of thiomersal and modification in the procedure of production of the pertussis vaccine to reduce the toxicity, to produce better quality of whole cell pertussis vaccine. To achieve this, at the time of production of the whole cell pertussis vaccine, at Kasauli, as per the standard procedure recommended by WHO, three parallel batches of the pertussis culture were inactivated in fermenter before harvesting and thiomersal was used only one time for suspending the bacterial mass after harvesting. The resultant modified vaccine so prepared when tested showed that it was of better quality as compared to the one produced by standard procedure, when tested in mice.

Congenital CMV infection in symptomatic infants in Delhi and surrounding areas.

Many viral infections are associated with significant maternal and fetal consequences during pregnancy among which cytomegalovirus is one of the most important agent, globally. Both primary and recurrent infection due to this virus can result in fetal infection. Samples from Congenital Anoammaled babies are referred to NICD from Delhi based Government hospitals and surrounding areas for diagnosis of congenital infections like Toxoplasm, Rubella, CMV and Herpes. In the present study, accumulated data is presented for the most common teratogenic virus--Cytomegalovirus prevalence as a causative agent for congenital infection in New Born babies at Delhi and surrounding areas. 96 samples from symptomatic babies in the age group of few days to 6 months exhibiting different congenital anomalies, were reported between 1 st Jan 04 to 30 th April/05. All the blood samples were tested for the detection of CMV (IgM) antibodies using m-capture ELISA technique. 18(18.75%) samples from babies showed positive titres for CMV-IgM antibodies. None of the mothers of positive babies were found positive for CMV-IgM antibodies but all were serologically exposed to CMV virus previously as their serum samples were positive for CMV-IgG antibodies indicating primary infection in the past or reactivation/reinfection with a different strain of CMV in the early pregnancy.

Immuneresponse to recombinant hepatitis B vaccination in adults.

The present study was conducted to find out the seroconversion following Recombinant Hepatitis B vaccination in healthy adults. Eighty healthy adults (males and females) of age group 18 yrs to 60 yrs were chosen for the study. Their prevaccination blood samples tested negative for HBsAg and Anti HBs antibodies by ELISA test. The subjects were administered 3 doses of recombinant Hepatitis B-(Engerix B) vaccine at 0, 1 and 6 months duration using 20 micrograms of vaccine per dose. Seropositivity (anti HBs titre > or = 10 mIU) after 2 doses was 48.75% and was 91.25% after 3 doses of the vaccine. 8.75% of the vaccinees did not seroconvert. The non responders when further scrutinized did not show evidence of HIV or Hepatitis C infection and they had a normal haemogram and normal immunoglobulins (IgA,IgM,IgG) levels. However 2 such subjects were found to be positive for anti HBc IgG antibodies indicating chances of Hepatitis B infection from a mutant strain of HBV where it is not possible to detect presence of HBs Ag using currently available diagnostic kits.