title: Trypanosoma cruzi: effects of social stress in Calomys callosus a natural reservoir of infection.
abstract: Social environment can represent a major source of stress affecting cortisol and/or corticosterone levels, thereby altering the immune response. We have investigated the effects of social isolation on the development of Trypanosoma cruzi infection in female Calomys callosus, a natural reservoir of this protozoan parasite. Animals were divided in groups of five animals each. The animals of one group were kept together in a single cage. In a second group, four females were kept together in a cage with one male. In the final group, five individuals were kept isolated in private cages. The isolated animals showed body weight reduction, decreased numbers of peritoneal macrophages, lower global leucocytes counts, smaller lytic antibody percentage and a significantly higher level of blood parasites compared to the other animals. Their behavior was also altered. They were more aggressive than grouped females, or females exposed to the presence of a male. These results suggest that isolation creates a distinct social behavior in which immunity is impaired and pathogenesis is enhanced.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, FCFRP-USP, Universidade de São Paulo, Avenida do Café s/no., 14040-903 Ribeirão Preto, SP, Brazil.
authors.forename: Carla Domingues
authors.initials: CD
authors.lastname: Santos
authors.forename: Míriam Paula Alonso
authors.initials: MP
authors.lastname: Toldo
authors.forename: Antônio Marcos Aparecida
authors.initials: AM
authors.lastname: Levy
authors.forename: José Clóvis
authors.initials: JC
authors.lastname: Prado
mesh_terms: D000208:Acute Disease; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D014355:Chagas Disease / Q000209:etiology / Q000635:transmission / Q000662:veterinary*; D004195:Disease Models, Animal; D004197:Disease Reservoirs / Q000469:parasitology*; D005260:Female; D007958:Leukocyte Count / Q000662:veterinary; D017737:Macrophages, Peritoneal / Q000502:physiology; D008297:Male; D018512:Parasitemia / Q000209:etiology / Q000469:parasitology / Q000662:veterinary; D011897:Random Allocation; D012376:Rodent Diseases / Q000209:etiology* / Q000469:parasitology / Q000635:transmission; D016205:Sigmodontinae / Q000469:parasitology*; D013312:Stress, Physiological / Q000150:complications / Q000276:immunology / Q000662:veterinary*; D014349:Trypanosoma cruzi / Q000276:immunology / Q000502:physiology
chemical_list: D000913:Antibodies, Protozoan