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Authors
Isaac Ghinai (1) , Jackie Cook(2), Teddy Tun Win Hla(1), Hein Myat Thu Htet(1), Tom Hall(2), Inke Lubis(2), Rosanna Ghinai(3), Therese Hesketh(1), Ye Naung(4), Mya Mya Lwin(4), Tint Swe Latt(4), David L. Heymann(2), Colin Sutherland(2), Chris Drakeley(2), Nigel Field(1).
1 University College, London, UK
2 London School of Hygiene and Tropical Medicine, UK
3 Royal United Hospital, Bath, UK
4 University of Medicine (II), Yangon, Myanmar
Background
The spread of artemesinin-resistant Plasmodium falciparum (Pf) is a global health concern. WHO hopes to eliminate malaria in South East Asia to contain this threat. Myanmar has the highest reported regional malaria burden, but few general population data exist. We investigated malaria epidemiology in central Myanmar to inform regional malaria control.
Method
We did a cross-sectional, probability sample of Phyu township, Bago Region during the wet season; August-September 2013. Interviewers collected clinical and behavioural data, recorded tympanic temperature and obtained dried blood spots for PCR and ELISA (serology) analysis. Pf positive samples were tested for genetic mutations in the K13 region that might confer artemesinin resistance. Estimated type-specific malaria PCR prevalence and seroprevalence with 95% confidence intervals (CI) were calculated, with regression analysis to identify risk factors for Pf. Data were weighted to account for unequal selection probabilities.
Results
Data were collected from 1641 participants aged 1-90 years from 505 households. The prevalence by PCR for all malaria species was low (2.5% (CI 1.6-3.8)). Pf was the most common species (n=20, 1.1% (0.5-2.5)), and five Pf samples tested positive for K13 mutations. We detected Plasmodium knowlesi in 16 samples (1.0% (0.6-1.9)) andPlasmodium vivax in 7 samples (0.4% (0.1-1.3)). 9.4% of participants had antibodies to Pf antigens and this increased with age. The force of infection was 9-fold higher in those older compared to those younger than 23 years (LR test p=0.016). Other risk factors for Pf antibodies included male gender and low socio-economic status.
Conclusion
This is the first population-based seroprevalence study from central Myanmar. We found low malaria prevalence overall. However, our data suggest endemic transmission continues, probably associated with behavioural risk factors amongst working-age men. The presence of K13 mutations has important implications for the spread of artemisinin resistance, and lends urgency to the elimination agenda.