title: Acaricidal effect and histological damage induced by Bacillus thuringiensis protein extracts on the mite Psoroptes cuniculi.
abstract: BACKGROUND
  The mite Psoroptes cuniculi is a common worldwide ectoparasite and the most frequently found in rabbit farms. It causes significant economic losses on commercial rabbit breeding associated with poor leather quality, reduced conception rates, weight loss, poor growth and death. Several strategies have been proposed for the treatment of mange caused by this mite, ranging from the use of acaricides, entomopathogenic fungi, essential oils and vaccines. However, therapy and control of both human scabies and animal mange are still based mainly on the use of drugs and chemicals such as ivermectin, which involves disadvantages including genotoxic and cytotoxic effects, resistance and environmental damage. Bacillus thuringiensis is a bacterium, innocuous for human being, domestic animals and plants that produces highly biodegradable proteins, and has been used worldwide for biological control. The aim of this work was to find an alternative treatment based on biological control for scabies caused by Psoroptes cuniculi, using protein extracts from strains of Bacillus thuringiensis.
  
  
  METHODS
  P. cuniculi mites were obtained from naturally infected New Zealand rabbits, and different doses of protein from B. thuringiensis were added to the mites. We measured mortality and obtained the median lethal concentration and median lethal times. For histological analysis, the mites were fixed in 10% formalin, processed according to the paraffin embedded tissue technique. Sections were stained with hematoxylin-eosin to observe the general histological structure.
  
  
  RESULTS
  We report here for the first time evidence about the in vitro acaricidal effect caused by the strain GP532 of B. thuringiensis on the mite Psoroptes cuniculi, with an LC50 of 1.3 mg/ml and a LT50 of 68 h. Histological alterations caused by B. thuringiensis on this mite, included the presence of dilated intercellular spaces in the basal membrane, membrane detachment of the peritrophic matrix and morphological alterations in columnar cells of the intestine.
  
  
  CONCLUSIONS
  Since this mite is an obligate ectoparasite that affects rabbits, goats, horses, cows and sheep, B. thuringiensis protein extracts are proposed as a potential treatment for biological control of mange in farm animals.
authors.affiliation: Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. dunstand_ipalogy@outlook.com.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Dunstand-Guzmán
authors.affiliation: Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. penacg@uaem.mx.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Peña-Chora
authors.affiliation: Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. challalc@gmail.com.
authors.forename: Claudia
authors.initials: C
authors.lastname: Hallal-Calleros
authors.affiliation: Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Av. Universidad 3000, Col. Copilco, 04510, Ciudad de México, Mexico. drmvzmariomtz@gmail.com.
authors.forename: Mario
authors.initials: M
authors.lastname: Pérez-Martínez
authors.affiliation: Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. vmanuelh@uaem.mx.
authors.forename: Víctor Manuel
authors.initials: VM
authors.lastname: Hernández-Velazquez
authors.affiliation: Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70228, DF 04510, México, Mexico. jmontor66@biomedicas.unam.mx.
authors.forename: Jorge
authors.initials: J
authors.lastname: Morales-Montor
authors.affiliation: Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. ivan.flores@uaem.mx.
authors.forename: Fernando Iván
authors.initials: FI
authors.lastname: Flores-Pérez
mesh_terms: D056810:Acaricides / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D005260:Female; D008297:Male; D008924:Mite Infestations / Q000188:drug therapy / Q000662:veterinary*; D010572:Pest Control, Biological / Q000379:methods*; D040042:Psoroptidae / Q000187:drug effects*; D011817:Rabbits / Q000469:parasitology*
chemical_list: D056810:Acaricides; D001426:Bacterial Proteins