Effectiveness of transfluthrin-coated inflammable-fumes insecticide-paper (Rambo™) in the prevention of malaria in Kano, Nigeria

Abstract

Background: A 15-month community-based randomized controlled trial was conducted with the aim of assessing the effectiveness of transfluthrin-coated inflammable-fumes insecticide-paper (TCIP) (Rambo™) on indoor mosquitoes and malaria. Methods: The study was conducted in two communities, Panshekara and Danbare, Kano, Nigeria, randomly selected as intervention and control, respectively. One hundred and fifty Households (HH) were systematically selected in each of the two and their doors and windows were netted with mesh-wire. In the intervention community, there were netted-alone and netted+TCIP administered HHDs. Participants were allowed to the use of insecticide-treated mosquito nets. An additional 20 HHDs were randomly selected within the two communities as internal controls and were neither netted nor administered TCIP. Fever, blood-film microscopy for malaria parasite, hematocrit, and entomological indices (indoor mosquito collection and determination of species at breeding sites) were conducted quarterly. Pyrethrum spray collection technique was used to collect adult mosquitos monthly from rooms in both communities. Main malaria vector species were identified using molecular techniques such as polymerase chain reaction. ELISA was used to identify circumsporozoite protein (CSP) of Plasmodium falciparum. Results: A total 2565 persons were studied in Panshekara (1208) and Danbare (1357). There was a declining trend in malaria through 4 quarters in Panshekara compared to baseline (χ2 -trend, P = 0.02) and slight reduction in proportion with anemia. In Panshekara, a total of 1592 Culex species were collected, out of which 911 (57.2%) were from the internal control, 440 (27.6%) were from the screened netted, and 241 (15.1%) from netted+TCIP treated HHDs. Three hundred and ninety-six Anopheline malaria vectors were collected, out of which 339, 27, and 30 were from the control, netted, and netted+TCIP treated sites, respectively. In comparison to the baseline prenetting phase, wire netting alone provided 51% protection against the nuisance of culicine mosquitoes, whereas netting plus TCIP provided 73% protection against Culicine mosquitoes. The main malaria vector species were Anopheles gambiae s. s and Anopheles arabiensis, but Anopheles funestus could not be analyzed further. CSP of P. falciparum was seen in all the 3 vector species. Conclusions: Very slight reduction in malaria and anemia was observed. Protection conferred by TCIP was modest against Culex spp., but small against the malaria vectors. TCIP complimented netting with Trial number-ATMR2010050002022487 (Pan-African-Clinical-Trial-Group).