Sporadic cases of adult measles: a research article

Measles caused by a paramyxovirus, characterized by fever, malaise, cough, coryza conjunctivitis, a maculopapular rash is known to result in pneumonia, encephalitis and death. Fatal cases of measles in Sri Lanka are rare after implementation of the National Immunization Programme in 1984. Thereafter 0.1% case fatality rate was observed during October 1999-June 2000 which is a very low figure compared to other regional countries. Immunization guidelines were further revised in 2001, 2011 and in 2012 when additional immunization was recommended to age group 4-21 years; who are likely to have inadequate immunization, in order to achieve elimination of Measles by 2020. However, in 2013-2014, 4690 cases were reported and the majority were children less than 1 year of age. The occurrence in adults is hard to retrieve in published epidemiological reports, however had been 38% (out of 1008 patients) in the 3rd quarter of 2013. During this outbreak 73/101 (72%) reported from the North Central Province of Sri Lanka had been more than 12 years of age with 50% being more than 29 years. 14 Sri lankan adult patients [median age 32 years (range 25-48)] who presented sporadically from June 2014 to March 2016, with confirmed measles infection were enrolled retrospectively after informed consent. Details with regards to their clinical presentation, immunization and other relevant areas were collected using an interviewer administered questionnaire or using patient management records.

The patients presented with high fever, headache, severe body aches, sore throat, dry cough, intense tearing, red eyes and posterior cervical lymphadenopathy over 3-5 days duration. Later they developed discrete maculopapular rash helping the diagnosis. They had a variable degree of leucopenia, lymphocytosis, thrombocytopenia and derangements in the liver functions mimicking any other acute febrile illnesses such as dengue, chikungunya, leptospirosis or Zika virus infection.

At least a 3-5 day delay in the diagnosis was observed (even after the appearance of the rash in some patients), due to non-awareness of its occurrence, unfamiliarity of measles in adults, non-specific nature of the illness and non-availability of rapid diagnostics, risking transmission to the immune-compromised or non-immune staff or patients. Identification of the source of infection in these sporadic adult cases and their virologic surveillance and molecular epidemiology will be important to interrupt the transmission and to achieve the targeted elimination of measles from Sri Lanka by 2020.