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Trypanosoma evansi is an important pathogen that causes changes in nitric oxide (NO) levels and antioxidant enzymes, as well as oxidative stress. The present study evaluated the in vivo effect of T. evansi infection on frequency and index of DNA damage in liver, heart, spleen and total blood of rats. Twenty rats were assigned into two groups with ten rats each, being subdivided into four subgroups (A1 and A2, 5 animals/group; and B1 and B2, 5 animals/group). Rats in the subgroups A1 and A2 were used as control (uninfected) and animals in the subgroups B1 and B2 were inoculated with T. evansi (infected). NO in serum and the comet assay were used to measure DNA damage index (DI) and damage frequency (DF) in liver, heart, spleen and total blood of infected rats. Increased NO levels on days 3 and 9 post-infection (PI) was observed (P < 0.001). Also, it was verified an increase on DI and DF in the evaluated organs on days 3 and 9 PI (P < 0.001). Our data show that T. evansi infection causes genotoxicity due to the production of NO, causing not only the death of the protozoan, but also inducing DNA damage in the host., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the effect of treatment with liposomal (L-DMZ) and conventional (C-DMZ) diminazene aceturate formulations on hepatic and renal functions of rats, experimentally infected with Trypanosoma evansi. For this purpose, 72 Wistar rats (Rattus norvegicus) were divided into six groups (A, B, C, D, E, and F). Each group was subdivided into two other subgroups in order to assess the biochemical and histological results on days 7 and 40 post-treatment (PT). Treatments were carried out based on two different therapeutic protocols: L-DMZ and C-DMZ at 3.5mg/kg(-1), single dose (groups C and D), and five successive doses within intervals of 24h (groups E and F). Groups A and B corresponded to uninfected and infected (without treatment) animals, respectively. Sample collections were held on days 7 and 40 PT for the assessment of hepatic [alkaline phosphatase (AP), alanine transferase (ALT), albumin, gamma glutamil transferase (GGT) and renal functions (creatinine and urea). Additionally, the histology of fragments of liver, kidney, and spleen was performed. Animals in group B showed a significant increase in AP, GGT, ALT, and urea when compared with group A. On day 7 post-inoculation (PI), the biochemical analysis showed a reduction (P<0.05) of AP and GGT, while the levels of urea were increased in groups C, D, E, F. On day 40 PT, ALT was increased in these same groups when compared with group A. In histopathology, changes in liver samples were observed on day 7 PT in groups D and F, especially regarding the area and density of the hepatocytes. Renal analysis exhibited changes in glomerular space, glomerular, and corpuscular areas in group E. Therefore, these results allowed us to conclude that the treatment with L-DMZ and C-DMZ led to variable biochemical changes, which defined the functions of the liver and kidneys of treated animals, since the main histopathology alterations were observed in animals treated with liposomes, at their higher dosages. Thus, treatments with L-DMZ and C-DMZ in five consecutive doses were effective although being followed by liver toxicity., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Trypanosoma evansi infections in domestic animals are characterized by anemia and thrombocytopenia. The cause of the platelets decrease is unknown, but researchers suggest that thrombocytopenia may result from damage of the bone marrow, reduced survival of platelets, auto-immune thrombocytopenia, disseminated intravascular coagulation and splenic sequestration. Some of these causes have already been tested by our research group and found to be unrelated. Therefore, this study has the objective of testing the hypothesis that splenic sequestration might be responsible for thrombocytopenia in T. evansi-infected rats. A total of 28 rats assigned to four groups were used in the experiment. Group A rats were splenectomized and infected with T. evansi, group B rats were infected with T. evansi, group C rats were splenectomized, but not infected and group D rats were normal controls. Five days post-infection all rats were anesthetized and blood was collected in order to measure the number of circulating platelets, fibrinogen levels, prothrombin time (PT) and activated partial thromboplastin time (aPTT). The spleens of groups B and D were weighed at necropsy. The infected animals (groups A and B) showed a significant reduction in platelets and increased PT and aPTT when compared to negative control groups (groups C and D). Animals from group A showed increased levels of fibrinogen. The mean weight of spleen differed between group B (2.62g) and group D (0.55g). It was concluded that there is no relationship between thrombocytopenia and splenic sequestration in infection by T. evansi., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A semi-solid culture system was used to study the effects of trypanosome infection in two species of mice on the propagation of progenitor cells from the bone marrow and spleen. The deer mouse (Peromyscus maniculatus) survived infection with Trypanosoma (T.) equiperdum for more than 15 days. During the first 10 days there was inhibition of development of granulocyte-monocyte colonies from progenitor cells in the bone marrow. B-lymphocyte progenitors in the spleen showed increased activity, producing colonies 140-300% above normal control groups during the same period. - Conversely, all Balb/c mice infected with the trypanosomes died within 10 days with fulminating parasitemia and massive spleen enlargement. There was a general activation of progenitor cells; B-lymphocytes from the spleen and bone marrow and granulocyte-monocyte colonies from bone marrow, although this was not sustained more than 4 days after infection. - In chronically infected deer mice the pattern of response of the bone marrow and spleen progenitor cells was significantly different over successive weekly intervals. Periodicity of response in these organs was displayed by recurring waves of activation and depression of the progenitor cells. - Thus, there were significant differences in response patterns of deer mice and Balb/c mice to T. equiperdum infection which could be established by the behavior of host lymphohaematopoietic progenitor cells in culture. We therefore suggest that such in vitro cultures may be useful in assessment of the immune response to trypanosomiasis by the host and also for the study of the pathology of both chronic and acute trypanosomiasis.

Both natural and experimental Trypanosoma lemmi infections in Norwegian lemmings caused slight anemias and hypoglycemia. Leucocyte counts remained the same. Adrenal and splenic hypertrophy were associated with natural infections whereas only splenic hypertrophy was present in the experimental infection. Grahamella sp. infections were also associated with adrenal and splenic hypertrophy in wild lemmings. It is suggested that blood parasites which are associated with anemia, hypoglycemia and adrenal hypertrophy might also interfere with both male and female reproduction, and should be considered in the interpretation of the population regulation of small rodents.