Measles Outbreak in a Migrant Population - medIND

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Sep 29, 2003 - Indian Journal of Pediatrics, Volume 72—October, 2005. 893. Letter to ... million cases and 7.77 lakh deaths in the year 2000.1. Measles is a ...
Letter to the Editor

Measles Outbreak in a Migrant Population Sir, Measles is an acute, highly infectious disease of childhood, characterized by fever, catarrhal symptoms and typical rash. Despite the availability of an effective vaccine, measles is still endemic in developing nations. World Health Organization (WHO) has reported 31 million cases and 7.77 lakh deaths in the year 2000.1 Measles is a serious childhood disease in India, with a median case fatality rate of 2.5%.2 Outbreaks of measles in a community tend to occur once the proportion of susceptibles reaches 40%.3 These outbreaks are often reported from the tribal and rural areas. The present study represents a focal outbreak of measles amongst a population of migrant labourers in the periurban area of Panchkula, Haryana, from late September to mid October 2003. The outbreak was investigated subsequent to the hospitalization of a child on 29th September 2003 with clinically suspected post measles meningoencephalitis. The affected settlement consisted of sixty families whereas the outbreak was confined to one particular pocket that formed the nucleus of the present study i.e. 33 houses. By the time the epidemic started many of the children from the locality were sent by their parents to their relatives’ families as a precautionary measure; thereby reducing the total reported cases. Adults were also involved in the epidemic. A house to house survey was carried out by the team of doctors from the departments of Community Medicine and Virology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, starting from the house where the first death was reported following an exanthematous fever (nodal point). The team moved in concentric circles until two consecutive circles yielded no additional cases. Subjects with fever more than 38°C and rash/ conjunctivitis were clinically diagnosed as measles.

History of vaccination against measles was recorded. Children of the affected locality were assessed for nutritional status using the criteria laid down by Indian Academy of Pediatrics (IAP). 4 Eleven children and one adult female had features of suspected measles accounting for 12 cases in the locality giving an overall attack rate of 7.7% (12/155) (Table 1). Higher attack rate (21%; 10/47) was observed in children below 5 years. Of the 78 children below 15 years of age assessed for malnutrition status, 12, 38 and 9 children had grades I, II and III malnutrition respectively. Three out of 11 children with suspected measles developed complications in the form of pneumonia (2) and meningoencephalitis (1) with a case fatality rate of 16.7% (2/12). History of measles vaccination was available with only 2 children out of 78 surveyed who did not suffer in the epidemic. The mortality rate for the present outbreak was 16.7% and can be attributed to high degree of malnutrition prevalent among children of the affected slum (60.2% grade II and grade III) and due to lack of adequate case management since the population relies more on traditional medicine and healers. Respiratory complications in the form of pneumonitis is the most common fatal complication of measles, as has been observed in the present study since two of the three affected children had pneumonia as post measles complications. Serum samples from six patients and 10 apparently healthy contacts were subjected for detection of measlesspecific IgM antibodies using commercially available microELISA for confirmation of recent infection. Viral isolation studies could not be carried due to lack of acute phase samples. Measles-specific IgM antibodies could be detected in 4 of the 6 clinically suspected measles patients, indicating an acute infection.

TABLE 1. Demography, Viral Serology and Outcome of Clinically Suspected Measles Patients (n=12) S. No. Age (yr)

Sex

Measles-specific IgM antibody

Suspected Measles cases with viral serology 1 1½ M Negative 2 2 F Negative 3 25 F Positive 4 2 F Positive 5 6 M Positive 6 2½ F Positive Suspected measles cases without viral serology 7 4 F ND* 8 3 M —do— 9 4 F —do— 10 2 M —do— 11 3 M —do— 12 4 M —do—

Complications

Outcome

Nil Nil Nil Hospitalized with meningoencephalitis Nil Nil

Survived —do— —do— —do— —do— —do—

Hospitalized with pneumonia Treated by local practitioner for pneumonia Residual exanthamatous rashes on the body —do— Nil —do—

Death —do— Survived —do— —do— —do—

*ND-Not done due to non-availability of sample.

Indian Journal of Pediatrics, Volume 72—October, 2005

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R.K. Ratho et al Worldwide, measles is the fifth leading cause of death among children less than 5 years despite the global measles vaccination coverage of 80%. In developing nations like India, measles is a major cause of morbidity and a significant contributor to childhood mortality. Vaccination is the cornerstone against measles and is an important component of national immunization programme of India. It has been observed that with vaccine coverage of more than 80% the interval between the outbreaks lengthens from 2-4 yrs to 4-8 yrs and is associated with lower case fatality rates. 5,6 A mass vaccination campaign against measles as well as health education was initiated by the health authorities in the affected locality as soon as the present outbreak was recognized. Thus, the present outbreak in the periurban slum area re-emphasizes the need to strengthen the surveillance of the vulnerable population, high routine vaccine coverage with first dose and provision of second dose of measles vaccine as recommended by WHO and UNICEF7.

REFERENCES 1. World Health Organization. Global measles mortality reduction and regional elimination, 2000-2001. Part I, Wkly Epidemiol Rec 2000, 77: 50-55. 2. Singh J, Sharma RS, Verghese T. Measles mortality in India: A review of community based studies. J Commun Dis 1994; 26: 203-214. 3. Park K. Mealses. In Park’s textbook of Preventive and Social Medicine. 17th edn. Jabalpur; Banarsidas Bhanot Publishers, 2002; 117-120. 4. Singh M. Anthropometry for assessment of nutritional status. In Pediatrics Clinical Methods. 1 st edn. New Delhi; Sagar Publications, 1992; 41-53. 5. Kambarami RA, Nathoo KJ, Nkrumah FK, Pirie DJ. Measles epidemic in Harare, Zimbabwe, despite high measles immunization coverage rates. Bull WHO 1991; 69: 213-219. 6. Lamb WH. Epidemic measles in a highly immunized rural West African (Gambian) village. Rev Infect Dis 1988; 10: 457462. 7. World Health Organization and United Nations Children’s Fund. Measles Mortality Reduction and Regional Elimination: Strategic Plan, 2000-2005. Geneva; WHO, 2001.

R.K. Ratho, Baijayantimala Mishra, Tarundeep Singh1, Pooja Rao, Rajesh Kumar1. Departments of Virology and 1Community Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Fax: 91-172-2744401, 2745078 Email: [email protected]; [email protected]

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Indian Journal of Pediatrics, Volume 72—October, 2005