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 country 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 excluding 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.

Can a quantitative assessment of SARS-CoV-2 PCR predict degree of severity and outcomes in critical care patients with COVID-19?

Real-Time polymerase chain reaction (qPCR) is the gold standard diagnostic method for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cycle threshold (Ct) is defined as the number of heating and cooling cycles required during the PCR process. Ct-values are inversely proportional to the amount of target nucleic acid in a sample. Our aim, in this retrospective study, was to determine the impact of serial SARS-CoV-2 qPCR Ct-values on: mortality, need for mechanical ventilation (MV) and development of acute kidney injury (AKI) in patients admitted to the intensive care unit (ICU) with COVID-19. Ct values were evaluated during the time points from pre-ICU admission to week 1, week 2 and week 3 during ICU stay; impact on mortality, need for MV and AKI was determined. There was a continuous increment in Ct-values over the ICU stay from 1st week through to 3rd week. Although not significant, lower ICU 1st week Ct-values were associated with Black ethnicity, increased need for MV and mortality. However, patients who had developed AKI at any stage of their illness had significantly lower Ct-values compared to those with normal renal function. When ICU 1st-week Ct-values are subcategorised as <20, 20-30 and >30 the 28-day survival probability was less for patients with Ct-values of <20. This report shows that the impact of Ct-values and outcomes, especially AKI, among patients at different time points prior to and during ICU stay, larger studies are required to confirm out findings.

The laboratory investigation of a measles outbreak in the eve of its elimination in Sri Lanka.

BACKGROUND: Measles is highly contagious and cause significant morbidity and mortality. Sri-Lanka has the goal to eliminate endogenous measles by 2020 in par with WHO. OBJECTIVE: To describe laboratory confirmation and genotype distribution of measles cases during the outbreak occurred from mid-March to May 2019, Sri-Lanka STUDY DESIGN: This retrospective study was conducted at National Measles Reference Laboratory (NMRL), Sri-Lanka. All samples received were tested according to the testing flow chart at NMRL with WHO recommended kits. Blood samples were tested for anti-measles IgM and IgG with IgG avidity for IgG positives. Samples within 5days post-onset rash were tested with measles real-time RT-PCR. Products of genotyping PCR were sent to Regional Reference Laboratory, Thailand for sequencing. Subsequent phylogenetic analysis was done at NMRL. Data were analyzed by descriptive statistics. RESULTS: A total of 182 blood and 46 throat/nasopharyngeal swabs were received from 195 suspected cases and 37(19 %) were positive for measles by anti-measles IgM, rRT-PCR or both. Majority was females, with mean age of 20 years. Cases represented three main geographical areas; Western-35 %, Central-32 % and Southern-27 %. High avidity IgG was detected in 27/37(73 %). Sequencing data of six cases (4 from Western and 2 from Central province) revealed genotype D8. CONCLUSION: Nineteen percent of the suspected patients were measles positive with 73 % having re-infections. Majority were 22 years or over. Measles genotype was D8 in two provinces, suggesting the spread of virus within the country. Laboratory confirmation with measles PCR; IgG avidity and sequencing/genetic analysis is critical in the verge of measles elimination.