title: Viability of sporulated oocysts of Neospora caninum after exposure to different physical and chemical treatments.
abstract: The aim of the present study was to evaluate the viability of Neospora caninum sporulated oocysts after various chemical and physical treatments. Bioassays in gerbils and molecular techniques (PCR-RFLP) were used for identification of the oocysts shed by experimentally infected dogs. Sporulated oocysts were purified and divided into 11 treatment groups as follows: absolute ethanol for 1 hr; 20 C for 6 hr; 4 C for 6 hr; 60 C for 1 min; 100 C for 1 min; 10% formaldehyde for 1 hr; 10% ammonia for 1 hr; 2% iodine for 1 hr; 10% sodium hypochlorite for 1 hr; 70% ethanol for 1 hr; and one group was left untreated and kept as a positive control. All chemical treatments were performed at room temperature (37 C). A total of 33 gerbils, or 3 gerbils per treatment, were used for bioassays. After treatment, the oocysts were divided into aliquots of 1,000 oocysts and orally administered to gerbils. After 63 days, the gerbils were anesthetized and killed with 0.2 ml of T61; blood and tissue samples were collected for serological (IFAT and western blotting), molecular (real-time PCR), histopathology, and immunohistochemical tests. Treatments were considered effective only if all 5 detection techniques tested negative. High temperatures at 100 C for 1 min and 10% sodium hypochlorite for 1 hr were the only treatments that met this condition, effectively inactivating all oocysts.
authors.affiliation: Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Av Prof Orlando M de Paiva, 87 Cidade Universitária, CEP 05508-270 São Paulo, Brazil.
authors.forename: Aldo F
authors.initials: AF
authors.lastname: Alves Neto
authors.forename: Luciana A
authors.initials: LA
authors.lastname: Bandini
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Nishi
authors.forename: Rodrigo M
authors.initials: RM
authors.lastname: Soares
authors.forename: David
authors.initials: D
authors.lastname: Driemeier
authors.forename: Nadia A B
authors.initials: NA
authors.lastname: Antoniassi
authors.forename: Gereon
authors.initials: G
authors.lastname: Schares
authors.forename: Solange M
authors.initials: SM
authors.lastname: Gennari
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001681:Biological Assay / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000469:parasitology; D002020:Buffaloes; D003048:Coccidiosis / Q000469:parasitology / Q000662:veterinary*; D016054:DNA, Protozoan / Q000032:analysis; D004202:Disinfectants / Q000633:toxicity; D004285:Dogs; D004587:Electrophoresis, Agar Gel / Q000662:veterinary; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D005849:Gerbillinae; D007150:Immunohistochemistry / Q000662:veterinary; D007165:Immunosuppression Therapy / Q000662:veterinary; D018688:Neospora / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D033661:Oocysts / Q000187:drug effects / Q000502:physiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013696:Temperature; D013997:Time Factors
chemical_list: D000913:Antibodies, Protozoan; D016054:DNA, Protozoan; D004202:Disinfectants