title: Impact of repeated NeemAzal-treated blood meals on the fitness of Anopheles stephensi mosquitoes.
abstract: BACKGROUND
  Herbal remedies are widely used in many malaria endemic countries to treat patients, in particular in the absence of anti-malarial drugs and in some settings to prevent the disease. Herbal medicines may be specifically designed for prophylaxis and/or for blocking malaria transmission to benefit both, the individual consumer and the community at large. Neem represents a good candidate for this purpose due to its inhibitory effects on the parasite stages that cause the clinical manifestations of malaria and on those responsible for infection in the vector. Furthermore, neem secondary metabolites have been shown to interfere with various physiological processes in insect vectors. This study was undertaken to assess the impact of the standardised neem extract NeemAzal on the fitness of the malaria vector Anopheles stephensi following repeated exposure to the product through consecutive blood meals on treated mice.
  
  
  METHODS
  Batches of An. stephensi mosquitoes were offered 5 consecutive blood meals on female BALB/c mice treated with NeemAzal at an azadirachtin A concentration of 60, 105 or 150 mg/kg. The blood feeding capacity was estimated by measuring the haematin content of the rectal fluid excreted by the mosquitoes during feeding. The number of eggs laid was estimated by image analysis and their hatchability assessed by direct observations.
  
  
  RESULTS
  A dose and frequency dependent impact of NeemAzal treatment on the mosquito feeding capacity, oviposition and egg hatchability was demonstrated. In the 150 mg/kg treatment group, the mosquito feeding capacity was reduced by 50% already at the second blood meal and by 50 to 80% in all treatment groups at the fifth blood meal. Consequently, a 50 - 65% reduction in the number of eggs laid per female mosquito was observed after the fifth blood meal in all treatment groups. Similarly, after the fifth treated blood meal exposure, hatchability was found to be reduced by 62% and 70% in the 105 and 150 mg/kg group respectively.
  
  
  CONCLUSIONS
  The findings of this study, taken together with the accumulated knowledge on neem open the challenging prospects of designing neem-based formulations as multi-target phytomedicines exhibiting preventive, parasite transmission-blocking as well as anti-vectorial properties.
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. edembo@gmail.com.
authors.forename: Edson G
authors.initials: EG
authors.lastname: Dembo
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. solomonabay@gmail.com.|School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia. solomonabay@gmail.com.
authors.forename: Solomon M
authors.initials: SM
authors.lastname: Abay
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. nisha.dahiya@unicam.it.
authors.forename: Nisha
authors.initials: N
authors.lastname: Dahiya
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. ogboijb@yahoo.com.
authors.forename: Johnbull S
authors.initials: JS
authors.lastname: Ogboi
authors.affiliation: Department of Life Sciences, Imperial College London, London, United Kingdom. g.christophides@imperial.ac.uk.
authors.forename: George K
authors.initials: GK
authors.lastname: Christophides
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. giulio.lupidi@unicam.it.
authors.forename: Giulio
authors.initials: G
authors.lastname: Lupidi
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via Montesano 49, 80131, Naples, Italy. g.chianese@unina.it.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Chianese
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. l.lucantoni@griffith.edu.au.|Current address: Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia. l.lucantoni@griffith.edu.au.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Lucantoni
authors.affiliation: School of Pharmacy, University of Camerino, Piazza dei Costanti, 62032, Camerino, MC, Italy. annette.habluetzel@unicam.it.
authors.forename: Annette
authors.initials: A
authors.lastname: Habluetzel
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects / Q000502:physiology*; D000962:Antimalarials / Q000494:pharmacology*; D031601:Azadirachta / Q000737:chemistry*; D001769:Blood; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000187:drug effects / Q000502:physiology*; D036701:Limonins / Q000494:pharmacology*; D008288:Malaria / Q000635:transmission*; D051379:Mice; D008807:Mice, Inbred BALB C; D010058:Oviposition; D010936:Plant Extracts / Q000494:pharmacology
chemical_list: D000962:Antimalarials; D036701:Limonins; D010936:Plant Extracts; C010329:azadirachtin