Laboratory and Field Studies on Herpetosoma Trypanosomes From Portugal

Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence of trypanosomes which were found in 33 of the 197 (11.1 %) Mus spretus and in 9 of the 29 (31 %) Crocidura russula observed. To our knowledge, this was the first time that trypanosomes were isolated from these mammals species. In the liver of one dead C. russula was observed different parasite forms. The studies of infectivity to experimental rodents, analyses of the DNA buoyant density and the isoenzymatic profiles, show that trypanosomes isolates from M. spretus were identical to Trypanosoma musculi isolates from Mus musculus. However the isolates from C. russula, although related to the isolates from murine rodents, were clearly separated from these and close to Trypanosoma microti. These findings may allow further studies on the detection of their vectors and on the study of trypanosome reproduction.publishersversionpublishe

Trypanosoma vivax Infections: Pushing Ahead with Mouse Models for the Study of Nagana. I. Parasitological, Hematological and Pathological Parameters

African trypanosomiasis is a severe parasitic disease that affects both humans and livestock. Several different species may cause animal trypanosomosis and although Trypanosoma vivax (sub-genus Duttonella) is currently responsible for the vast majority of debilitating cases causing great economic hardship in West Africa and South America, little is known about its biology and interaction with its hosts. Relatively speaking, T. vivax has been more than neglected despite an urgent need to develop efficient control strategies. Some pioneering rodent models were developed to circumvent the difficulties of working with livestock, but disappointedly were for the most part discontinued decades ago. To gain more insight into the biology of T. vivax, its interactions with the host and consequently its pathogenesis, we have developed a number of reproducible murine models using a parasite isolate that is infectious for rodents. Firstly, we analyzed the parasitical characteristics of the infection using inbred and outbred mouse strains to compare the impact of host genetic background on the infection and on survival rates. Hematological studies showed that the infection gave rise to severe anemia, and histopathological investigations in various organs showed multifocal inflammatory infiltrates associated with extramedullary hematopoiesis in the liver, and cerebral edema. The models developed are consistent with field observations and pave the way for subsequent in-depth studies into the pathogenesis of T. vivax - trypanosomosis

Characterization of Trypanosoma cruzi Strains Isolated from Chronic Chagasic Patients, Triatomines and Opossums Naturally Infected from the State of Rio Grande do Sul, Brazil

Thirty-five Trypanosoma cruzi strains were isolated from chronic chagasic patients, triatomines and opossums from different municipalities of the State of Rio Grande do Sul. Parasites were characterized by means of mice infectivity, enzyme electrophoresis and randomly amplified polymorphic DNA (RAPD) analysis. Twenty-nine strains were isolated from chagasic patients, 4 from triatomines (2 from Triatoma infestans and 2 from Panstrongylus megistus) and 2 from opossums Didelphis albiventris. Thirty-three T. cruzi strains were of low and 2 strains of high virulence in mice. Both virulent strains were isolated from P. megistus. Isoenzyme analysis of the strains showed 3 different zymodemes. Eleven strains isolated from chagasic patients and 2 from D. albiventris were Z2. Eighteen strains from patients and 2 from T. infestans were ZB and 2 T. cruzi strains isolated from P. megistus were Z1. RAPD profiles obtained with 4 random primers showed a high genetic heterogeneity of the T. cruzi strains. Zymodeme 2 and ZB strains were the more polymorphic. A band sharing analysis of the RAPD profiles of Z2 and ZB strains using 3 primers, showed a very low percentage of shared bands, 20% among 13 ZB strains and 14% among 13 Z2 strains. According to the isoenzyme results, 3 T. cruzi populations were present in State of Rio Grande do Sul. Zymodeme 2 and ZB strains were found infecting man (domiciliar transmission cycle) whereas Z1 strains were found infecting the sylvatic vector P. megistu