title: Immunization of lambs with the S48 strain of Toxoplasma gondii reduces tissue cyst burden following oral challenge with a complete strain of the parasite.
abstract: This study evaluates the influence of immunizing lambs with the incomplete S48 strain of Toxoplasma gondii, on parasite dissemination following a live oral challenge with a complete strain of T. gondii (M4). Lambs were culled at 14, 28 and 42 days post challenge. Parasite DNA was detected at significantly (p<0.0001) lower levels in samples from the vaccinated/challenged group (0% in heart and 5.9% in skeletal muscles), when compared to the non-vaccinated/challenged animals (75% heart, 87.9% skeletal muscle). S48 T. gondii DNA was found in muscle or lymph nodes until 42 days post infection, suggesting that parasite DNA or tachyzoites could persist longer after immunization than previously thought. Non-vaccinated/challenged animals showed more frequent lesions in muscles and central nervous system than the vaccinated animals. These results demonstrate that vaccination of lambs with the incomplete S48 T. gondii strain, can protect against establishment of tissue cysts following challenge with a complete strain of T. gondii. Consumption of undercooked meat containing T. gondii cysts is a major route of transmission to people, therefore vaccination of food animals may improve the safety of meat for human consumption.
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK. Electronic address: frank.katzer@moredun.ac.uk.
authors: Frank
authors: F
authors: Katzer
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK; Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Balcarce CC276, Argentina.
authors: German
authors: G
authors: Canton
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Alison
authors: A
authors: Burrells
authors: Biomathematics & Statistics Scotland, The King's Buildings, Edinburgh EH9 3JZ, Scotland, UK.
authors: Javier
authors: J
authors: Palarea-Albaladejo
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Ben
authors: B
authors: Horton
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Paul M
authors: PM
authors: Bartley
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Yvonne
authors: Y
authors: Pang
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Francesca
authors: F
authors: Chianini
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
authors: Elisabeth A
authors: EA
authors: Innes
authors: Instituto de Ganadería de Montaña (CSIC-ULE), 24346 Grulleros (León), Spain.
authors: Julio
authors: J
authors: Benavides
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001831:Body Temperature; D005786:Gene Expression Regulation; D006321:Heart / Q000469:parasitology; D007668:Kidney / Q000469:parasitology; D008099:Liver / Q000469:parasitology; D008168:Lung / Q000469:parasitology; D008198:Lymph Nodes / Q000469:parasitology; D008562:Membrane Glycoproteins / Q000235:genetics; D018482:Muscle, Skeletal / Q000469:parasitology; D015800:Protozoan Proteins / Q000235:genetics; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000517:prevention & control*; D014122:Toxoplasma / Q000145:classification / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000517:prevention & control*
chemical_list: D000953:Antigens, Protozoan; C095047:GRA6 protein, Toxoplasma gondii; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C087692:SAG3 protein, Toxoplasma gondii
keywords: Ovine; Tissue cysts; Toxoplasmosis; Transmission; Vaccine; Zoonosis