title: Protective efficacy of menthol propylene glycol carbonate compared to N, N-diethyl-methylbenzamide against mosquito bites in Northern Tanzania.
abstract: BACKGROUND
  The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08), Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET), either as a single dose or in combination (blend), both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus.
  
  
  METHODS
  In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00  hr to 01:00  hr.
  
  
  RESULTS
  A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30%) were An. gambiae s.l while 66 (2.70%) were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx. quinquefasciatus were significantly prevented from blood feeding compared to An. gambiae s.l.
  
  
  CONCLUSIONS
  The incorporation of these topical repellents for protection against insect bites can be of additional value in the absence or presence of IRS and ITNs coverage. However, a combination of both the physical (bed nets) and the repellent should be used in an integrated manner for maximum protection, especially before going to bed. Additional research is needed to develop repellents with longer duration of protection.
authors.affiliation: Division of Livestock and Human Diseases Vector Control, Mosquito section, Tropical Pesticides Research Institute, P.O.BOX 3024, Arusha, Tanzania. pat.kweka@gmail.com
authors.forename: Eliningaya J
authors.initials: EJ
authors.lastname: Kweka
authors.forename: Stephen
authors.initials: S
authors.lastname: Munga
authors.forename: Aneth M
authors.initials: AM
authors.lastname: Mahande
authors.forename: Shandala
authors.initials: S
authors.lastname: Msangi
authors.forename: Humphrey D
authors.initials: HD
authors.lastname: Mazigo
authors.forename: Araceli Q
authors.initials: AQ
authors.lastname: Adrias
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Matias
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D003465:Culex / Q000187:drug effects*; D003671:DEET / Q000494:pharmacology; D005260:Female; D006801:Humans; D007299:Insect Bites and Stings / Q000517:prevention & control; D007302:Insect Repellents / Q000494:pharmacology*; D007303:Insect Vectors / Q000187:drug effects*; D008610:Menthol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009032:Mosquito Control / Q000379:methods; D019946:Propylene Glycol / Q000494:pharmacology*; D011409:Propylene Glycols / Q000494:pharmacology*; D013636:Tanzania
chemical_list: D007302:Insect Repellents; D011409:Propylene Glycols; C576878:menthol propylene glycol carbonate; D003671:DEET; D008610:Menthol; D019946:Propylene Glycol