Genetic Evidence of Focal Plasmodium falciparum Transmission in a Pre-elimination Setting in Southern Province, Zambia

Julia C. Pringle, Sofonias Tessema, Amy Wesolowski, Anna Chen, Maxwell Murphy, Giovanna Carpi, Timothy M Shields, Harry Hamapumbu, Kelly M. Searle, Tamaki Kobayashi, Ben Katowa, Michael Musonda, Jennifer Claire Stevenson, Philip E Thuma, Bryan Greenhouse, William J Moss, Douglas Norris

Research output: Contribution to journalArticle

Abstract

BACKGROUND: Southern Province, Zambia has experienced a dramatic decline in Plasmodium falciparum malaria transmission in the past decade and is targeted for elimination. Zambia's National Malaria Elimination Program recommends reactive case detection (RCD) within 140 m of index households to enhance surveillance and eliminate remaining transmission foci. METHODS: To evaluate whether RCD captures local transmission, we genotyped 26 microsatellites from 106 samples collected from index (n = 27) and secondary (n = 79) cases detected through RCD in the Macha Hospital catchment area between January 2015 and April 2016. RESULTS: Participants from the same RCD event harbored more genetically related parasites than those from different RCD events, suggesting that RCD captures, at least in part, infections related through local transmission. Related parasites clustered in space and time, up to at least 250 m from index households. Spatial analysis identified a putative focal transmission hotspot. CONCLUSIONS: The current RCD strategy detects focal transmission events, although programmatic guidelines to screen within 140 m of index households may fail to capture all secondary cases. This study highlights the utility of parasite genetic data in assessing programmatic interventions, and similar approaches may be useful to malaria elimination programs seeking to tailor intervention strategies to the underlying transmission epidemiology.

Original languageEnglish (US)
Pages (from-to)1254-1263
Number of pages10
JournalThe Journal of infectious diseases
Volume219
Issue number8
DOIs
StatePublished - Apr 8 2019

Fingerprint

Zambia
Plasmodium falciparum
Parasites
Malaria
Spatial Analysis
Falciparum Malaria
Microsatellite Repeats
Epidemiology
Guidelines
Infection

Keywords

  • case detection
  • malaria
  • microsatellites
  • molecular epidemiology
  • reactive
  • screen-and-treat

ASJC Scopus subject areas

  • Immunology and Allergy
  • Infectious Diseases

Cite this

Genetic Evidence of Focal Plasmodium falciparum Transmission in a Pre-elimination Setting in Southern Province, Zambia. / Pringle, Julia C.; Tessema, Sofonias; Wesolowski, Amy; Chen, Anna; Murphy, Maxwell; Carpi, Giovanna; Shields, Timothy M; Hamapumbu, Harry; Searle, Kelly M.; Kobayashi, Tamaki; Katowa, Ben; Musonda, Michael; Stevenson, Jennifer Claire; Thuma, Philip E; Greenhouse, Bryan; Moss, William J; Norris, Douglas.

In: The Journal of infectious diseases, Vol. 219, No. 8, 08.04.2019, p. 1254-1263.

Research output: Contribution to journalArticle

Pringle, Julia C. ; Tessema, Sofonias ; Wesolowski, Amy ; Chen, Anna ; Murphy, Maxwell ; Carpi, Giovanna ; Shields, Timothy M ; Hamapumbu, Harry ; Searle, Kelly M. ; Kobayashi, Tamaki ; Katowa, Ben ; Musonda, Michael ; Stevenson, Jennifer Claire ; Thuma, Philip E ; Greenhouse, Bryan ; Moss, William J ; Norris, Douglas. / Genetic Evidence of Focal Plasmodium falciparum Transmission in a Pre-elimination Setting in Southern Province, Zambia. In: The Journal of infectious diseases. 2019 ; Vol. 219, No. 8. pp. 1254-1263.
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AU - Pringle, Julia C.

AU - Tessema, Sofonias

AU - Wesolowski, Amy

AU - Chen, Anna

AU - Murphy, Maxwell

AU - Carpi, Giovanna

AU - Shields, Timothy M

AU - Hamapumbu, Harry

AU - Searle, Kelly M.

AU - Kobayashi, Tamaki

AU - Katowa, Ben

AU - Musonda, Michael

AU - Stevenson, Jennifer Claire

AU - Thuma, Philip E

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AU - Moss, William J

AU - Norris, Douglas

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N2 - BACKGROUND: Southern Province, Zambia has experienced a dramatic decline in Plasmodium falciparum malaria transmission in the past decade and is targeted for elimination. Zambia's National Malaria Elimination Program recommends reactive case detection (RCD) within 140 m of index households to enhance surveillance and eliminate remaining transmission foci. METHODS: To evaluate whether RCD captures local transmission, we genotyped 26 microsatellites from 106 samples collected from index (n = 27) and secondary (n = 79) cases detected through RCD in the Macha Hospital catchment area between January 2015 and April 2016. RESULTS: Participants from the same RCD event harbored more genetically related parasites than those from different RCD events, suggesting that RCD captures, at least in part, infections related through local transmission. Related parasites clustered in space and time, up to at least 250 m from index households. Spatial analysis identified a putative focal transmission hotspot. CONCLUSIONS: The current RCD strategy detects focal transmission events, although programmatic guidelines to screen within 140 m of index households may fail to capture all secondary cases. This study highlights the utility of parasite genetic data in assessing programmatic interventions, and similar approaches may be useful to malaria elimination programs seeking to tailor intervention strategies to the underlying transmission epidemiology.

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