msp1, msp2, and glurp genotyping to differentiate Plasmodium falciparum recrudescence from reinfections during prevention of reestablishment phase, Sri Lanka, 2014-2019

BACKGROUND

Sri Lanka after eliminating malaria in 2012, is in the prevention of re-establishment (POR) phase. Being a tropical country with high malariogenic potential, maintaining vigilance is important. All malaria cases are investigated epidemiologically and followed up by integrated drug efficacy surveillance (iDES). Occasionally, that alone is not adequate to differentiate Plasmodium falciparum reinfections from recrudescences. This study evaluated the World Health Organization and Medicines for Malaria Venture (MMV) recommended genotyping protocol for the merozoite surface proteins (msp1, msp2) and the glutamate-rich protein (glurp) to discriminate P. falciparum recrudescence from reinfection in POR phase.

METHODS

All P. falciparum patients detected from April 2014 to December 2019 were included in this study. Patients were treated and followed up by iDES up to 28 days and were advised to get tested if they develop fever at any time over the following year. Basic socio-demographic information including history of travel was obtained. Details of the malariogenic potential and reactive entomological and parasitological surveillance carried out by the Anti Malaria Campaign to exclude the possibility of local transmission were also collected. The msp1, msp2, and glurp genotyping was performed for initial and any recurrent infections. Classification of recurrent infections as recrudescence or reinfection was done based on epidemiological findings and was compared with the genotyping outcome.

RESULTS

Among 106 P. falciparum patients, six had recurrent infections. All the initial infections were imported, with a history of travel to malaria endemic countries. In all instances, the reactive entomological and parasitological surveillance had no evidence for local transmission. Five recurrences occurred within 28 days of follow-up and were classified as recrudescence. They have not travelled to malaria endemic countries between the initial and recurrent infections. The other had a recurrent infection after 105 days. It was assumed a reinfection, as he had travelled to the same malaria endemic country in between the two malaria attacks. Genotyping confirmed the recrudescence and the reinfection.

CONCLUSIONS

The msp1, msp2 and glurp genotyping method accurately differentiated reinfections from recrudescence. Since reinfection without a history of travel to a malaria endemic country would mean local transmission, combining genotyping outcome with epidemiological findings will assist classifying malaria cases without any ambiguity.

Prevalence of hypertension, diabetes and obesity: baseline findings of a population based survey in four provinces in Sri Lanka

OBJECTIVE

To determine the prevalence of selected cardiovascular risk factors in adult Sri Lankan population in four provinces.

DESIGN

Cross-sectional, based on a stratified cluster sampling method.

SETTINGS

Four provinces, namely the Western, North Central, Southern and Uva.

PATIENTS

Six thousand and forty seven participants (2692 men) between the age of 30 and 65 years were surveyed.

MEASUREMENTS

Risk factors measured included height, weight, waist and hip circumference. Waist to hip ratio and body mass index were calculated, and overweight (23 kg/m2) and obesity (> or = 25 kg/m2) determined. Hypertension (systolic blood pressure > or = 140 mmHg or diastolic blood pressure > or = 90 mmHg or use of anti-hypertensive medications), and diabetes mellitus (fasting serum plasma glucose level > or = 7 mmol/L or use of anti-diabetic medications) and impaired fasting glycaemia (> or = 6.1 to < 7 mmol/L) were also determined.

RESULTS

The prevalence of hypertension as defined was 18.8% (CI 14.5-23.1) for men and 19.3% (CI 12.2-26.4) for women. The prevalence of diabetes was 14.2% (CI 11.9-16.5) for men and 13.5% (CI 6.9-20.1) for women while impaired fasting glycaemia was 14.2% for men and 14.1% for women. The mean body mass index was 21.5 kg/m2 (SD = 3.7) in men. It was lower than that in women, 23.3 kg/m2 (SD = 4.5). The prevalence of obesity was 20.3% in men and 36.5 % in women. Regional differences were seen in the mean fasting blood glucose and prevalence of diabetes, and mean BMI and prevalence of obesity were highest in Western province. Mean blood pressure and prevalence of hypertension were highest in the Uva Province. Southern Province had the lowest prevalence of hypertension and diabetes, and North Central Province had lowest anthropometric measures of obesity.

CONCLUSIONS

The prevalence of the selected cardiovascular risk factors is common in the adult Sri Lankan population surveyed. Regional differences exist in the prevalence of these risk factors. The prevalence of high level of risk factors requires urgent public health action.