Data/hora: 23/09/2024 12:37:28

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	19/03/1997	
Data da última atualização: 	31/03/2017	
Autoria: 	RIVERA DAVILA, A. M.; SILVA, R. A. M. S.; RAMIREZ, L.	
Afiliação: 	UFMS. Centro Universitario de Corumba (Corumba, MS); EMBRAPA. Centro de Pesquisa Agropecuaria do Pantanal (Corumba, MS).	
Título: 	Protection from lethal infection by prior immunization with an homologous Trypanosoma evansi Strain.	
Ano de publicação: 	1995	
Fonte/Imprenta: 	In: CONGRESSO DA SOCIEDADE BRASILEIRA DE PARASITOLOGIA, 14., 1995, Goiania. Resumos... Goiania: [s.n.] 1995. p.325.	
Idioma: 	Inglês	
Conteúdo: 	Trypanosoma evansi is a salivarian trypanosome belonging to subgenus Trypanozoon. It is the causative agent of Surra in the Old World and Mal de Caderas in the subtropical area of Argentina and Pantanal, Brazil. Differents methods are used for protection against salivarian-trypanosome infection: a)infection with irradiated trypanosomes, b)infection with trypanosome components and c) infection and quimiotherapy. Only the ultimate is used with successful results for homologous but not heterologous challenges. Survival of acute Trypanosoma cruzi infection has been suggested to be develop in naturally susceptible host and can be enhanced in inherently resistant animals by prior immunization. Highly susceptible C3H/He strain of laboratory mice can be protected froman otherwise lethal infection by prior immunization with an avirulent T.cruzi strain. Enhanced resistance of Balb/c mice to T.congolense infection with 10.3 but not 10.5 of homologous variants was related. Also has been reported protection its conferred for non-surface components antigens in homologous T.evansi challenge. Athimic mice are capable of control T.brucei and T.rhodesiense replication and become resistant to subsequente challenge with homologous parasites. Four males Wistar rats weighting 169.5 g were challenged with log. 7.34 trypomastigotes of T. evansi. Mean parasitemia was log 6.45/ml on the first day-post-infection (d.p.i.) in 100% of rats. All animals were given Berenil (7mg/Kg) on 4th d.p.i. Clearance of trypomastigotes was successful on 1 day-post-quimiotherapy (d.p.q.) Seventeen d.p.q. rats were re-chanllenge with log. 7.69 trypomastigotes of homologous variant (double dose of first challenge), protection was successful during 49 after first-challenge, when animals were re-challenge with log 8.47 trypamastigotes of homologous variant (1345% more first inocolum) obtained of sucessive syringe passaged in others Wistar rats. Partial protection was observed, prepatent period was of 4 days, and log. 67,7/ml (in 75% of rats) and log. 8.52/ml (in 25% of rats) on the first and 9th day of parasitemia were respectivily registred. Control group parasitemia was log 6.38/ml and log 8.7/ml on first and 5th d.p.i. (died). Possible antigenic variation of strain on the third challenge or overdose of inocolum are postuled. Serum sample were collected during experiment for after evaluation. We verificated protection conferred against homologous T. evansi strain, as demonstred by others authors with T. congolense, T. brucei, T. cruzi and T. evansi. More studies are necessary to determinate which mechanisms are involved in the partial protection.	
Palavras-Chave: 	Infeccao letal; Lethal infection.	
Thesagro: 	Imunização.	
Thesaurus Nal: 	immunization; Pantanal; Trypanosoma evansi.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (34192-1) - UPC - SP - PP - SP15171 -  - 15171 - DIS