Resurgence of measles virus infection in an eliminated country, Sri Lanka

Objective:To describe the situation of measles in Sri Lanka from May to November,2023 and to define the role of virology laboratory towards case confirmation and epidemiological and genetic characterization of the outbreak.Methods:This retrospective study analyzed all samples tested for measles from 1st of May to 30th of November,2023 at National Measles Rubella Laboratory,Sri Lanka.According to the World Health Organization(WHO)algorithm,serum and oropharyngeal/nasopharyngeal swabs were tested with WHO recommended kits for anti-measles IgM and measles virus specific RNA,respectively.Selected RNA positive samples were sequenced at reference laboratory,India.Analysis of sequencing data and construction of phylogenetic tree were carried out at National Measles Rubella Laboratory.Data was analyzed using descriptive statistics.Results:Of the total 1132 serum samples and 497 oropharyngeal/nasopharyngeal swabs from 1326 patients,657(49.5%)patients were confirmed as measles by anti-measles IgM,measles virus specific RNA or both.Males(55.6%,n=365)and the age group from>20 to≤30 years(33.0%,n=217)predominated positive patients.All provinces reported measles positive cases.All samples sequenced(100%,n=42)were genotype D8 with 95.2%(n=40)bearing Victoria.Australia origin.Conclusions:We described resurgence of measles in an eliminated country,confirming the genotype to be D8,one of the two genotypes currently circulating globally.Further,the study strongly convinced the importance of a strengthened virological surveillance system in an eliminated country,despite its eliminated status.

The 2013 measles outbreak in Sri Lanka: experience from a rural district and implications for measles elimination goals

Background:Sri Lanka was the first country in the Southeast Asian region to achieve its measles elimination goal in 2011.In 2012,the measles immunization schedule changed from a measles vaccine at 9 months to a measles,mumps and rubella vaccine at 12 months.However in 2013,Sri Lanka reported its worst recent outbreak of measles.This study investigated a part of this outbreak in order to describe its epidemiology.Methods:A prospective study was carried out at the university medical unit of the Teaching Hospital,Anuradhapura(THA),the third largest hospital in Sri Lanka,from October 2013 until March 2014.An epidemiological profile of patients was constructed,case confirmation was done on all suspected cases and the basic demographic details of these suspected cases were obtained from the available records.Results:From January 2013 to March 2014,101 measles suspects were admitted to the THA.Until June 2013,all suspected cases were aged below 12 months of age.During the study period(15 months),the total number of patients aged below 9 months,9 to 12 months,1 to 11 years,12–29 years and over 29 years were 10(9.9%),11(10.9%),6(5.9%),37(36.6%)and 36(35.6%),respectively(data missing-1).Out of the 33 patients clinically suspected,32 tested positive for measles.Common clinical features included:fever(n=33,100%),maculopapular rash(n=33),conjunctivitis(n=31),posterior cervical lymphadenopathy(n=23)and Koplik’s spots(n=8).Features suggestive of pneumonia were observed among 30(90.9%)patients and 26(78.8%)had diarrhoea.Two patients(6.1%)who developed severe pneumonia received care at an intensive care unit due to respiratory difficulties.Out of 33 patients,15(45.5%)had prior immunization for measles,two(6.1%)reported that they never had a measles immunization and 16(48.5%)were unsure about their immunization status.Out of those who reported they were previously immunized,11(73.3%)belonged to the age group of 12–29 years.Conclusion:Because the first cases of this outbreak were infants,an increase in susceptible infants due to the change in the vaccine schedule could partly explain the outbreak.

Laboratory response to an infant with suspected measles vaccine associated fever and rash in Sri Lanka

Background:Measles is a highly contagious illness.Sri Lanka(SL)has eliminated the measles in 2019.The coun-try is at risk of importation of measles and there could be vaccine-associated measles like illnesses.Therefore,it is important to investigate patients with fever,rash to differentiate the wild-type from vaccine-type exclud-ing other suspected pathogens to direct infection prevention and control strategies.The objective is to describe the laboratory investigation procedure in an immunocompetent child,developed fever,rash following measles containing vaccine in post-measles eliminated period,SL.Methods:This laboratory based investigation was carried out in National Measles Laboratory,SL.Blood and throat swab were received from a patient with fever,rash,cough and coryza developed at tenth day of receiving the measles containing live-attenuated vaccine.Samples were tested for measles,rubella,and other relevant pathogens according to the laboratory testing algorithm for an immunocompetent child with fever,rash and flu like symptoms.Results:Measles vaccine type A,Edmonston-strain virus was detected after sequencing in throat swab and measles IgM and IgG were positive at sixth-week of illness-onset.In addition,influenza A RNA was detected in throat swab at day-three with detectable parvoB19 IgM in blood sample received at sixth-week of post-onset symptoms.Conclusions:Measles like illness of this immunocompetent child who received measles containing vaccine could be due to measles vaccine-type A or influenza infection.In a measles eliminated,resource-limited setting in SL,there should be a well-defined,testing algorithm to exclude prevalent possible pathogens according to epidemiological and clinical information.

China vows to eliminate measles by 2012

China is drafting an action plan for measles control for the next few years which aims to eliminate measles by 2012, according to a health official.