The Durable Lining: A New Tool for Malaria Vector Control Compared to Other Classical Methods (Long Lasting Insecticide Treated Nets “LLIN” During a Village Scale Long Term Trial in Angola. I. Entomological Evaluation.

• Pierre Carnevale1,* Jean-Claude Toto2, Vincent Foumane2, Filomeno Fortes3, Guillaume Carnevale4, Frédérick Gay5

Citation: Carnevale P, Gay F, Toto J–C, Foumane V, Fortes F, Carnevale G. The Durable lining: a new tool for Malaria Vector Control Compared to other Classical Methods (Long Lasting Insecticide Treated nets “LLIN”; Indoor Residual Spraying) during a Village scale long term trial in Angola. I. Entomological Evaluation. Medp Public Health Epidemiol. 2022; 2(1): mpphe–202207001.

Abstract

  Background: Deltamethrin (“δ”) treated durable lining (“DL”) or “insecticide treated plastic sheeting” (“δITPS”) were used for a long term village–scale malaria vector control (VC) program in 8 villages around Balombo town (Benguela Province, Angola) either alone (in 2 villages) or associated with Long Lasting deltamethrin Insecticide treated Net (“δLLIN”) Permanet© 2.0 (in 2 villages) or following Indoor Residual Spraying with lambdacyhalothrin “λ” (“λIRS”) (in 2 villages) while LLIN P2.0 alone were considered as “golden standard” and implemented in 2 villages. 2 models of ITPS were used, “Wall lining” and “Zero Fly” with different deltamethrin concentration. A comprehensive evaluation, entomological and parasitological, was initially planned for 5 years. Entomological evaluation was based upon the regular use of the classical CDC Miniature Light Trap inside human houses. 

   Results: During these 5 years (2 years before and 3 years after full vector control implementation) 202 CDC “night catching sessions” were done, representing 1880 “trap– night”, 1152 Anopheles were captured, belonging to 10 species, the main vectors (“MV”) were Anopheles funestus and An. gambiae. After implementation of VC the densities of “main– vector/traps” dropped by # 70%, similarly with the 4 VC methods (#63% with LLIN alone; #69% with the association LLIN +ITPS model “Zero Fly”; # 82% with ITPS model “Wall Lining” alone and #75 % after 2 rounds of λIRS followed by ITPS installation). 28 of the 1133 anopheles analyzed procured an Elisa positive test i.e. a general positivity index of 2.47%; with 8.00% (n= 50) for An. gambiae; 3.61% (n= 498) for An. funestus and 2.06% for An. marshalli (n= 243). Infectivity of main vectors An. gambiae + An. funestus dropped, but not significantly, from 4.53%, (n= 375) to 2.59% (n=193) after vector control implementation.

    Conclusions: The fact that Durable Lining, even alone, were as efficient as Indoor Residual Spraying to reduce biting rate and inoculation rate of main vectors while having a longer lasting activity, and that the association Long Lasting Treated Nets + Durable Lining was not much better than a single method are important information for the National Malaria Control Program and other Malaria Control programs.

  Keywords: Anopheles, vector control, malaria, Angola, entomological evaluation, deltamethrin treated durable lining, Long Lasting insecticide (deltamethrin) treated Nets (LLIN), lambdacyhalothrin Indoor Residual Spraying.