Mass Screening and Treatment on the Basis of Results of a Plasmodium falciparum-Specific Rapid Diagnostic Test Did Not Reduce Malaria Incidence in Zanzibar

• Published in: The Internet journal of infectious diseases Vol. 211; no. 9; pp. 1476 - 1483
• Main Authors: Cook, Jackie, Xu, Weiping, Msellem, Mwinyi, Vonk, Marlotte, Bergström, Beatrice, Gosling, Roly, Al-Mafazy, Abdul-Wahid, McElroy, Peter, Molteni, Fabrizio, Abass, Ali K., Garimo, Issa, Ramsan, Mahdi, Ali, Abdullah, Mårtensson, Andreas, Björkman, Anders
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.05.2015
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antimalarials - therapeutic use; Child; Child, Preschool; Female; Humans; Incidence; Infant; Malaria, Falciparum - diagnosis; Malaria, Falciparum - drug therapy; Male; Mass Screening; Medicin och hälsovetenskap; Middle Aged; PARASITES; Plasmodium; Plasmodium falciparum; Polymerase Chain Reaction - methods; Seasons; Sensitivity and Specificity; Tanzania - epidemiology; Young Adult; Tanzania; ISW, Tanzania, Zanzibar; molecular methods; Plasmodium falciparum; Plasmodium vivax; diagnostic tests; mass screening and treatment; malaria elimination; Plasmodium ovale; Plasmodium malariae; subpatent; Zanzibar
• ISSN: 0022-1899; 1528-8366; 1537-6613; 1537-6613; 1528-8366
• DOI: 10.1093/infdis/jiu655

Background. Seasonal increases in malaria continue in hot spots in Zanzibar. Mass screening and treatment (MSAT) may help reduce the reservoir of infection; however, it is unclear whether rapid diagnostic tests (RDTs) detect a sufficient proportion of low-density infections to influence subsequent transmission. Methods. Two rounds of MSAT using Plasmodium falciparum-specific RDT were conducted in 5 hot spots (population, 12 000) in Zanzibar in 2012. In parallel, blood samples were collected on filter paper for polymerase chain reaction (PCR) analyses. Data on confirmed malarial parasite infections from health facilities in intervention and hot spot control areas were monitored as proxy for malaria transmission. Results. Approximately 64% of the population (7859) were screened at least once. P. falciparum prevalence, as measured by RDT, was 0.2% (95% confidence interval [CI],.1%-.3%) in both rounds, compared with PCR measured prevalences (for all species) of 2.5% (95% CI, 2.1%-2.9%) and 3.8% (95% CI, 3.2%-4.4%) in rounds 1 and 2, respectively. Two fifths (40%) of infections detected by PCR included non-falciparum species. Treatment of RDT-positive individuals (4% of the PCR-detected parasite carriers) did not reduce subsequent malaria incidence, compared with control areas. Conclusions. Highly sensitive point-of-care diagnostic tools for detection of all human malaria species are needed to make MSAT an effective strategy in settings where malaria elimination programs are in the pre-elimination phase.