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K K Datta

Publications and source records attributed to K K Datta.

At least 37 records · Page 2Linked to original sources
PubMed1997

Measles vaccine efficacy in India: a review.

Different workers have used different designs to assess effectiveness of live, further attenuated measles vaccine i.e., seroconversion studies, outbreak investigations, field trials and coverage survey methods. The results were often contradictory. We reanalyzed data from these studies to find out optimum vaccine efficacy (VE) and its determinants in the Indian context. Although nutritional status and sex of the subjects did not affect seroconversion rates, the rates were greater among initially seronegative and older children. Overall seroconversion rates in 9-11 months children ranged between 56 and 96%. Studies showing poor seroconversion had an inadequate sample size and/or technical flaws that detracted from the reliability of results. However, appropriately designed studies demonstrated seroconversion rates of more than 90% in 9-11 months children who were initially seronegative. Since 5-10% of 9-11 months old infants had persistent measles maternal antibody, measles vaccine may be around 85-90% effective in this age group. These results are in agreement with the findings observed in outbreak investigations. These outbreaks fulfilled all the criteria which are considered necessary for optimum estimation of VE in such settings; VE was found to be more than 90% in outbreak settings. Conversely, retrospective coverage surveys grossly under estimated VE (about 60%) which was probably due to misclassification of vaccination status of enrolled children. The surveys were undertaken in areas where immunization records were grossly incomplete and only few mothers retained immunization cards. Unfortunately, VE was also under estimated in field trials which were neither randomized nor blind, and no placebo injections were used in control children; many observations were on record which could explain the under estimation of VE. Reanalysis of data from different types of studies indicates that efficacy of measles vaccine given at 9-11 months of age is of the order of 85-90% in the Indian context.

Child, Preschool↗
PubMed1997

Sensitivity of neonatal tetanus surveillance system in India.

OBJECTIVE: To estimate the sensitivity of neonatal tetanus (NNT) surveillance in India. DESIGN: A comparison of two sets of data obtained from NNT mortality surveys and routine surveillance system. METHODS: NNT mortality surveys were undertaken in 1981, 1989 and 1992 using 30 cluster sampling technique. The data on reported incidence of NNT through routine surveillance system was taken from the published documents of Health Ministry and WHO. RESULTS: In 1981, the incidence of disease in a national survey was estimated to be 4 and 16.4 per 1000 live births in urban and rural areas, respectively. Follow up surveys in 1989 and 1992 estimated the overall incidence as 4 and 1.74 per 1000 live births, respectively. Comparing the reported and estimated by surveys, around 10% of NNT cases were reported. CONCLUSIONS: There is an urgent need to strengthen the routine surveillance system which at present grossly under-reports the NNT incidence in India.

Humans↗
PubMed1997

Epidemiology of endemic viral hepatitis in an urban area of India: a retrospective community study in Alwar.

In a community study during a reference period of 1 year, 192 cases of jaundice were detected in an urban population of 69,440 in Alwar, Rajasthan. Detected by paramedics and confirmed by physicians, these cases gave an annual incidence of 2.76 (95% CI: 2.37-3.15) per 1000 population. At least one of these patients died, giving a case fatality ratio of 0.6%. The jaundice cases occurred in all areas investigated, and affected all socioeconomic strata. About 94% of the affected families had only single cases. Although cases occurred throughout the year, more than 59% occurred during June-September, which are the summer and monsoon months. The incidence was highest (5.23 per 1000) among under-5-year-olds and declined progressively and significantly thereafter. Males had a higher incidence than females at all ages; the differences were not significant. Blood samples from 56 cases who had jaundice in the last 3 months of the reference period were tested for markers of viral hepatitis. Of these, 18 (32.1%), 1 (1.8%), 0, 2 (3.6%), and 4 (7.1%) were found to have hepatitis A, B, C, D and E, respectively. The etiology of the remaining 31 cases (55%) could not be established; previously, they would have been included in the NANB (non-A, non-B) category, inflating its proportion. Hepatitis A (HA) was the predominant type; being comparatively mild, it is perhaps underrepresented in hospital-based data. Many HA cases were in adults, which may be the beginning of an age shift of HA to the right owing to improvements in living standards of the study population. Five cases were carriers of hepatitis B virus (HBV), indicating the importance of HBV infection in India as well. Finally, the study found the annual incidence of laboratory-supported cases of viral hepatitis to be 1.24 (95% CI: 0.98-1.5) per 1000 population, which suggests that it is a major public health problem in India.

Adolescent↗
PubMed1996

Profile of epidemic emergencies in India during 1991-95.

Epidemic emergencies have shown increasing trend in India and most parts of the country appear to be vulnerable to these emergencies. In this paper we present a profile of epidemic emergencies attended by the National Institute of Communicable Diseases in the last five years, to delineate aspects that will promote better preparedness and management. Water borne and water related disease epidemics constituted more than 70% of the epidemic emergencies in India. Non 01 cholera epidemics constituted one fourth of total cholera epidemics during 1991-95. Most of the hepatitis outbreaks were attributed to Non A Non B. The source of infection in majority of the cholera and jaundice epidemics was contaminated water. Dengue and resistant typhoid fever were among other emergencies reported during last five years. Some of these epidemic were reported to local health authorities as mysterious diseases due to lack of public health laboratory facilities. Encephalitis and encephalitis like epidemics in the form of Liquor poisoning and chronic Heat syndrome encephalopathy were also observed. The re-emerging disease epidemics like plague in Beed, Pneumonic plague in Surat and malaria in Rajasthan were also investigated during 1994. These observations indicate the weakness in the epidemiological and laboratory surveillance besides inadequacy in water management practices and other socio environmental reasons.

Disaster Planning↗
PubMed1996

Unusual occurrence of cholera in Delhi during January 1994: epidemiological investigations.

Hundreds of laboratory-confirmed cholera cases occur every year in Delhi. However from 1965 through 1993, no cases of cholera nor carriers of Vibrio cholerae have been detected in the months January and February of all these years. Nevertheless, two cases occurred in January 1994. Both were children who acquired their infection locally. Six hundred fifty-eight rectal swabs collected from possible contacts were negative for V. cholerae. The next isolations could be made only in April, which is the usual beginning of the cholera season. The study suggests that cholera transmission can occur during the winter months in Delhi, but that it is not sustained.

Acute Disease↗
PubMed1996

Virologic surveillance of poliomyelitis in Delhi.

OBJECTIVE: Virologic surveillance of poliomyelitis to monitor the transmission of wild polio virus in the community. STUDY AREA: All major hospitals of Delhi and surrounding area. METHODS: Stool samples were collected from 1221 cases of acute flaccid paralysis during 1992-1994 and were subjected to virus isolation on RD and HEp2 cell line. Viruses isolated were analyzed further by microneutralization test using polio and nonpolio antisera. The polio isolates were further characterized as vaccine or wild type using ELISA and probe technology. RESULTS: Out of the 1221 cases tested, virus was isolated in 57.4%. Among the virus positive cases, polio was isolated in 57% and in 43% non polio entero viruses were detected. The most prevalent was polio virus type 1. Most of the strains were wild type. CONCLUSION: Wild polio virus was prevailing in the community under study between the years 1992-1994.

Humans↗
PubMed1996

Methods for estimating prevalence and incidence of senile cataract blindness in a district.

The problem of senile cataract blindness (SCB) is very acute in India, contributing to 80 per cent of total blindness. The national objective of reducing the prevalence of blindness from 1.49 per cent, during 1986-89 to 0.3 per cent by AD 2000 has necessitated the surgical correction of SCB to be the major activity. With the introduction of District Blindness Control Society (DBCS), there has been a substantial increase in the number of operations of SCB in those districts. However, in the absence of standard, feasible, simple and cost effective methods to estimate the prevalence and incidence of SCB, the DBCS may find it difficult to plan and execute its major activity in a realistic way. The paper suggests two such methods for the use by DBCS. Only five seemingly rational assumptions have been adopted for the purpose. The authors feel that proper field testing is required to be sure about the reliability and validity of these methods.

Adult↗
PubMed1996

Immunity to diphtheria in women of childbearing age in Delhi in 1994: evidence of continued Corynebacterium diphtheriae circulation.

Blood samples from 171 full-term pregnant women (aged 18-38 years) of middle socioeconomic status from Delhi were tested for diphtheria antitoxins by indirect hemagglutination (IHA) test. History of primary immunization/clinical diphtheria during childhood was not ascertainable, but none had been revaccinated against diphtheria at any time. About 94% women had very high antitoxin titers (> or = 0.125 IU/ ml); none had antitoxin titer less than 0.015 IU/ml, the minimum protective level. The titers were uniformly high in all age groups. However, women having 2 or more children had significantly higher antitoxin titers than those having no or one child (p < 0.01). The results from this study and historical data on diphtheria in Delhi are compatible with continued transmission of C. diphtheriae in recent times in Delhi which is of sufficient magnitude to boost the antitoxin levels in adults, especially mothers having two or more children. The study highlights the need of increasing the immunization coverage with DPT among children to reduce the transmission of Corynebacterium diphtheriae.

Adolescent↗
PubMed1995

An outbreak of viral hepatitis E: role of community practices.

A small localised outbreak of viral hepatitis due to HEV occurred in an educated and well placed community. The overall attack rate was found to be 1.9%; the children and adults were equally affected. No fatality was observed. Five blood samples collected from the cases of jaundice were found negative for Anti HAV IgM, HBsAg and Anti HBc IgM, but positive for Anti HEV. The infection spread by contamination of piped water by sewage system resulting from scarcity of water, intermittent water supply and installation of on-line private booster pumps by the residents. Community action, especially the boiling of drinking water till the quality of piped water improved, restricted jaundice cases to only one incubation period. The outbreak highlights the importance of community behaviour in first precipitating the crisis and then limitating the damage.

Adolescent↗
PubMed1995

Serodiagnosis of tuberculosis.

To overcome limitations of the conventional laboratory tests for the diagnosis of tuberculosis, attempts have been made in the past to develop a good serodiagnostic test. Until the availability of ELISA results obtained with various immunological techniques were of limited use. Even with ELISA, early attempts to estimate specific antimycobacterial antibodies in the serum were based on the use of crude mycobacterial antigens resulting in a very high false positivity. Better results were obtained with purified antigens. Various purified and semipurified antigens which when used in the ELISA test for estimating antibodies in the serum and other body fluids in cases of tuberculosis have given encouraging results. These include a glycolipid antigen from Myc. bovis BCG (ST = 88%, SP = 96%), antigen '5' (ST = 72%, SP = 91%) and a 38 Kd protein antigen (ST = 83%). Estimation of various mycobacterial antigens in different clinical specimens has also been studied using ELISA technique. Encouraging results have been obtained with the detection of a 43 Kd antigen, Lipoarabinomannan antigen and antigen '5' in the serum, CSF and other body fluids of cases of tuberculosis (ST = 80-100%, SP = 93-100%). The serological tests by detecting specific mycobacterial antigens and antibodies can be of great help in diagnosing the smear negative tuberculosis as these are rapid, inexpensive and simple to perform.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

An institutional outbreak of hepatitis E--reported first time from Calcutta city.

A sudden outbreak of hepatitis occurred in a micro-epidemic form, amongst the staff members of the School of Tropical Medicine, Calcutta, during May-June, 1995. A total of 21 persons developed jaundice, out of whom 11 members who attended the Virology Department and were tested for detection of different serological markers of hepatitis by ELISA. All the sera (N = 11) showed evidence of non-A, non-B infection by process of exclusion and 9 of the above sera showed evidence of anti-HEV when tested specifically. This is the first documented outbreak of viral hepatitis in respect of Calcutta.

Adult↗
PubMed1995

Validity of a mother's history of measles in children: a review of Indian literature.

A review of the available information on the validity of a mother's history of measles in children and its importance in Indian context is presented. A history of measles was found to have a median sensitivity (SN) of about 60% (n = 6; range 33-75) and a median specificity (SP) of about 95% (n = 5; range 79-100). A subclinical infection seems to be the most plausible explanation for the low SN. Two mechanisms for the development of subclinical infection have been suggested: (i) In infants, exposure to the virus in the households when maternal antibodies are just sufficient to prevent the disease but not the infection. (ii) In older children, exposure to a mild dose of virus outside the households. However, due to the misclassification of non measles cases as measles, the SN increases and SP decreases as the child grows older. The implications of low SN, high SP and varying predictive values of the mother's history of measles are discussed.

Child↗
PubMed1995

Appropriate season for measles immunisation campaign in India.

Review of literature on the seasonality of measles in India reveals that measles occur throughout the year with peaks around March, while October-November are the low transmission months. The epidemics of measles however, occur any time during the year. Nevertheless, measles vaccination campaigns are carried out in India in the Month of March to increase the vaccine coverage levels. Being the low transmission season, October and November may be more appropriate for undertaking measles campaigns in India.

Humans↗
PubMed1995

An outbreak of viral hepatitis in Jodhpur city of Rajasthan.

An outbreak of Viral hepatitis occurred in Jodhpur city of Rajasthan during April to June, 1994. The attack rate was 3.04 per cent among 0-14 years age group and 5.49% among the age group above 15 years, the overall attack rate being 4.5 per cent. Males were more affected than females. Epidemiological and serological findings suggest that the outbreak was due to enterically transmitted Non A Non B virus. The source of infection was drinking water contaminated with sewage.

Adolescent↗