Temporal and Spatial Differences between Symptomatic and Asymptomatic Malaria Infections in the Chittagong Hill Districts, Bangladesh

Kerry L. Shannon, Timothy Shields, Sabeena Ahmed, Hafizur Rahman, Chai Shwai Prue, Jacob Khyang, Malathi Ram, M. Zahirul Haq, Jasmin Akter, Mohammad Shafiul Alam, Gregory E. Glass, Myaing M. Nyunt, David A. Sack, David J. Sullivan, Wasif A. Khan, Frank C. Curriero

Research output: Contribution to journalArticlepeer-review

Abstract

Mapping asymptomatic malaria infections, which contribute to the transmission reservoir, is important for elimination programs. This analysis compared the spatiotemporal patterns of symptomatic and asymptomatic Plasmodium falciparum malaria infections in a cohort study of ~25,000 people living in a rural hypoendemic area of about 179 km2 in a small area of the Chittagong Hill Districts of Bangladesh. Asymptomatic infections were identified by active surveillance; symptomatic clinical cases presented for care. Infections were identified by a positive rapid diagnostic test and/or microscopy. Fifty-three subjects with asymptomatic P. falciparum infection were compared with 572 subjects with symptomatic P. falciparum between mid-October 2009 and mid-October 2012 with regard to seasonality, household location, and extent of spatial clustering. We found increased spatial clustering of symptomatic compared with asymptomatic infections, and the areas of high intensity were only sometimes overlapping. Symptomatic cases had a distinct seasonality, unlike asymptomatic infections, which were detected year-round. In a comparison of 42 symptomatic Plasmodium vivax and 777 symptomatic P. falciparum cases from mid-October 2009 through mid-March 2015, we found substantial spatial overlap in areas with high infection rates, but the areas with the greatest concentration of infection differed. Detection of both symptomatic P. falciparum and symptomatic P. vivax infections was greater during the May-to-October high season, although a greater proportion of P. falciparum cases occurred during the high season compared with P. vivax. These findings reinforce that passive malaria surveillance and treatment of symptomatic cases will not eliminate the asymptomatic reservoirs that occur distinctly in time and space.

Original languageEnglish (US)
Pages (from-to)1210-1217
Number of pages8
JournalAmerican Journal of Tropical Medicine and Hygiene
Volume107
Issue number6
DOIs
StatePublished - Dec 2022

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology
  • Parasitology

Fingerprint

Dive into the research topics of 'Temporal and Spatial Differences between Symptomatic and Asymptomatic Malaria Infections in the Chittagong Hill Districts, Bangladesh'. Together they form a unique fingerprint.

Cite this