Malaria in São Tomé and Principe: On the Brink of Elimination after Three Years of Effective Antimalarial Measures

Abstract

In 2005, São Tomé e Príncipe began an initiative aimed at reducing malaria-related mortality to zero. The program included mass coverage with two antivector intervention methods (indoor residual spraying and long-lasting insecticidal nets), artemisinin-based combination therapy, and intermittent preventive therapy in pregnancy with sulfadoxine-pyrimethamine. At the end of 2007, three years after intensified interventions began, malaria-attributed outpatient consultations, hospitalizations, and deaths decreased by more than 85%, 80%, and 95%, respectively, in all age groups. Mean prevalence of parasitemia and splenomegaly were also significantly reduced to 2.1% (P < 0.0001) and 0.3% (P < 0.0001) after two rounds of spraying from baseline prevalences of 30.5% and 48.8%, respectively. The dramatic reduction in malaria morbidity and mortality now enable serious consideration of new goals and strategies aimed at completely interrupting malaria transmission on these islands. We report evidence of the program's impact and the feasibility of and potential strategies for eliminating malaria from São Tomé e Príncipe.

Estimation of the Human Blood Index in Malaria Mosquito Vectors in Equatorial Guinea after Indoor Antivector Interventions

“…[27][28][29][30][31] Although some studies report zoophily in Afro-tropical vector populations, [5][6][7] we did not detect such behaviors. This may be because of the scarcity of non-human hosts in collection sites that results from an observed lack of animal husbandry practices in Equatorial Guinea relative to other sub-Saharan African localities.…”

“…gambiae s.s. preferentially feeding on dogs or cattle over human hosts. [5][6][7] The zoophily of these vectors could be explained as a response to indoor residual spraying (IRS) interventions combined with the use of long-lasting insecticide-treated nets (LLINs). 6 The insecticides used in such interventions have excito-repellent effects that drive host-seeking mosquitoes outdoors, where they may come into contact with non-human hosts.…”

High-Throughput Pooling and Real-Time PCR-Based Strategy for Malaria Detection

“…This phenomenon has been observed in other studies (26,28,44) and may have several causes: systematic errors in thick smear preparation can produce false-positive interpretations because of red cell fragments, platelets, other blood elements, or environmental particulate contamination (51), and clinical approaches that bias toward overtreatment for malaria may also bias laboratory personnel toward overdiagnosis (9). Declines in parasite prevalence in areas where malaria is endemic (5,8,45) may further compromise the positive predictive value of microscopy and limit the utility of microscopy for case detection in clinical studies.…”

“…Malaria control programs in areas of endemicity are producing significant decreases in clinical malaria episodes and parasite densities (5,8,22,32,45), and molecular diagnostics may become more critical in detecting parasitemias. Additionally, pooling samples for molecular diagnosis of malaria could make real-time PCR assays more feasible for large, clinical, resource-limited malaria studies.…”

International population movements and regional Plasmodium falciparum malaria elimination strategies

“…eradication | migration | network analysis | imported malaria | community detection S ignificant progress is being made in reducing the morbidity and mortality attributed to malaria globally (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), encouraging the Global Malaria Action Plan (GMAP) (11) to articulate a long-term vision for malaria eradication through shorter-term local efforts to eliminate malaria. A total of 34 of the 107 malaria endemic countries have declared they have a national policy for malaria elimination or are pursuing spatially progressive elimination within their borders (11)(12)(13).…”