title: Determination of erythrocyte susceptibility of Chinese sheep (Tan mutton breed) and French sheep (Vendéen breed) to Babesia sp. BQ1 (Lintan) by in vitro culture.
abstract: The Babesia species "BQ1 (Lintan)" is infective to sheep and goats. The species was isolated from Haemaphysalis qinghaiensis collected in the Gannan Tibet Autonomous Region, China in April 2000. In this study, an in vitro culture system was developed for the propagation of Babesia sp. BQ1 (Lintan). Continuous cultivation and 5.0% parasitemia was obtained in vitro in RPMI 1640 medium with sheep red blood cells (RBC) (7.5%) supplemented with Fetal Bovine Serum (FBS) (20%), Amphotericin B (0.5 microg/ml) and Gentamicin (50 microg/ml) in an incubator at 37 degrees C and 6% CO(2) in 24-well and 6-well plates. Parasitemia could attain 10% in 75 cm(2) flasks with the same culture medium but with 2.5% RBC. A clonal line of Babesia sp. BQ1 (Lintan) was screened using the limiting dilution method and designated G7. Growth of Babesia sp. BQ1 (Lintan) in vitro was measured by microtitre-based spectrophotometric method and from parasitemia counts. The generation time was between 20.57 h (based the A(405) of the culture supernatant) and 26.41 h (based on parasitemia). Three French sheep were successfully infected with the culture and the infectivity of the clonal line G7 was determined. Finally, this in vitro culture system was used to compare the susceptibility (capacity to sustain Babesia sp. growth in vitro) of RBC from French sheep (Vendéen breed) and Chinese sheep (Tan mutton breed) for Babesia sp. BQ1 (Lintan) and B. divergens. The lower susceptibility to B. divergens and Babesia sp. BQ1 (Lintan) of RBC from French sheep, compared to Chinese sheep, is discussed.
authors.affiliation: Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou 730046, China.
authors.forename: Guiquan
authors.initials: G
authors.lastname: Guan
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Moreau
authors.forename: Nadine
authors.initials: N
authors.lastname: Brisseau
authors.forename: Jianxun
authors.initials: J
authors.lastname: Luo
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
authors.forename: Alain
authors.initials: A
authors.lastname: Chauvin
mesh_terms: D000818:Animals; D001403:Babesia / Q000254:growth & development*; D001404:Babesiosis / Q000235:genetics / Q000469:parasitology / Q000662:veterinary*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004912:Erythrocytes / Q000469:parasitology*; D020022:Genetic Predisposition to Disease; D018512:Parasitemia / Q000235:genetics / Q000469:parasitology / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012337:RNA, Ribosomal, 18S / Q000737:chemistry / Q000235:genetics; D012756:Sheep; D012757:Sheep Diseases / Q000235:genetics / Q000469:parasitology*
chemical_list: D016054:DNA, Protozoan; D012337:RNA, Ribosomal, 18S