Mateus Anderson Otto

Biochemical changes in cats infected with Trypanosoma evansi

This study aimed at evaluating biochemical changes of cats (Felis catus) experimentally infected with Trypanosoma evansi. Seven animals were infected with 10(8) blood trypomastigotes per animal and six were used as controls. Blood smears were performed daily for 56 days and the hepatic, renal and muscular parameters in blood serum were evaluated at days 0, 7, 21, 35 and 49. The protozoan was found in the bloodstream 24-48 h post-inoculation (PI) and irregular peaks of parasitemia were observed throughout the experiment. Muscular enzymatic activities (aspartate aminotransferase and creatine kinase) were increased in infected cats compared to controls. Increased concentrations of total proteins and globulins and decreased levels of albumin and albumin/globulin ratio were observed in infected group versus the controls values (P<0.05). No alteration in serum activity of alanine aminotransferase, gamma-glutamyltransferase, creatinine and urea was observed in both groups.

Susceptibility of Trypanosoma evansi to human blood and plasma in infected mice.

Around 1900 Laveran and Mesnil discovered that African trypanosomes do not survive in the blood of some primates and humans. The nature of the trypanolytic factor present in these sera has been the focus of a long-standing debate between different groups. The aim of this study was to investigate the susceptibility of T. evansi isolates to therapy using human blood and plasma in experimentally infected mice. Forty-eight 2-month-old female mice (Mus musculus) were divided into six groups of eight animals per group (A, B, C, D, E and F). Plasma was obtained after blood collection in order to perform therapy. Animals from group A (positive control) were inoculated with T. evansi and treated with 0.2mL of saline solution. Animals from groups B and C were infected with the flagellate and received a curative treatment with 0.2mL of human blood (group B) and 0.2mL of human plasma (group C), 24h after infection. Animals from groups D and E received a prophylactic treatment with 0.2mL of human blood and 0.2mL of human plasma, respectively, 24h prior to the infection. Animals from group F (negative control) were not infected and received 0.2mL of saline solution. The four treatments (B, C, D and E) increased animals longevity when compared to group A. Prepatency period was longer in groups D (15 days) and E (37.7 days) under prophylactic immunotherapy. Moreover, no parasites were found in most of the animals 60 days post-inoculation (PI). Besides the longer longevity, treatments were capable of curing 50% of mice of group B, 37.5% of group C, 37.5% of group D and 25% of the animals from group E.

Patogenicidade de um isolado de Trypanosoma evansi em ratos inoculados com o parasito em sangue in natura e criopreservado

This study aimed to evaluate the Trypanosoma evansi strain pathogenicity (LPV-2005) in rats under passive immunity influence, of different concentrations and media preservation. Thirty six adult female Rattus norvergicus were separated in six equal groups. Groups A and B were inoculated with 105 T. evansi and groups C and D with 106 blood trypomastigotes per animal. Groups E and F were used as negative control in which the animals were inoculated with fresh and cryopreserved blood, without the parasite. Group A were composed of T. evansi infected born rats and cured females. Groups B, C and D were composed with animals never exposed to the LPV-2005 strain. All groups B and C animals received different doses of blood trypomastigotes kept in Wistar rats, while animals from group D were infected with cryopreserved blood kept in liquid nitrogen. The the strain pathogenicity was estimated by prepatency evaluation period, levels of parasitemia and animals longevity. Group D showed a longer prepatency period in comparison with other groups. The longevity of group D (27.8 days) was significantly different (P<0.05) from group C (4.8 days). Rats of the control group were euthanized 50 days postinfection. In conclusion, the tested inoculum-preservation methods and the infective dose of T. evansi influenced the pathogenicity of the LPV-2005 strain in rats. The presence of maternal antibodies did not prevent the infection and mortality of the rats by T. evansi.

Diminazene aceturate associated with sodium selenite and vitamin E in the treatment of Trypanosoma evansi infection in rats

The aim of this study was to evaluate the utilization of a standard treatment with diminazene aceturate against the infection caused by Trypanosoma evansi, associated to sodium selenite and vitamin E. In vitro tests showed trypanocidal effect related to the treatment with diminazene aceturate and sodium selenite, but vitamin E had no harmful effect on the trypanosomes. In vivo experiments utilized a total of 72 adult outbreed females rats, separated into 9 groups (A, B, C, D, E, F, G, H and I), 8 animals each. Group A was the uninfected group; groups B to I were infected with 0.2mL of blood containing 10(6) trypanosomes. Parasitemia was estimated daily by microscopic examination of blood smears. Group B served as positive control; group C was treated with diminazene aceturate; group D with sodium selenite; group E with vitamin E; group F received an association of diminazene aceturate and sodium selenite; group G received an association of diminazene aceturate and vitamin E; group H received an association of diminazene aceturate, sodium selenite and vitamin E, and group I received an association of sodium selenite and vitamin E. Diminazene aceturate was administrated in a single dose on the 3rd day post infection (PI). Sodium selenite and vitamin E were administered at the 3rd and 23rd day PI. In vivo tests showed increase of longevity in groups treated with diminazene aceturate associated with sodium selenite (groups F and H). No difference was found between groups C and E, thus the vitamin E did not increase the efficacy of treatment against T. evansi when associated to diminazene aceturate. The curative efficacy of treatments was 37.5, 87.7, 37.7 and 75% to the groups C, F, G and H, respectively. Other treatments showed no efficacy. The sodium selenite when combined with chemotherapy may represent an alternative in the treatment of trypanosomosis.

Trypanocidal activity of human plasma on Trypanosoma evansi in mice

This study aimed to test an alternative protocol with human plasma to control Trypanosoma evansi infection in mice. Plasma from an apparently 27-year-old healthy male, blood type A+, was used in the study. A concentration of 100 mg.dL(-1) apolipoprotein L1 (APOL1) was detected in the plasma. Forty mice were divided into four groups with 10 animals each. Group A comprised uninfected animals. Mice from groups B, C and D were inoculated with a T. evansi isolate. Group B was used as a positive control. At three days post-infection (DPI), the mice were administered intraperitoneally with human plasma. A single dose of 0.2 mL plasma was given to those in group C. The mice from group D were administered five doses of 0.2 mL plasma with a 24 hours interval between the doses. Group B showed high increasing parasitemia that led to their death within 5 DPI. Both treatments eliminated parasites from the blood and increased the longevity of animals. An efficacy of 50 (group C) and 80% (group D) of human plasma trypanocidal activity was found using PCR. This therapeutic success was likely achieved in the group D due to their higher levels of APOL1 compared with group C.

Duddingtonia flagrans: Centrifugal flotation technique with magnesium sulphate for the quantification and qualification of chlamydospores in sheep faeces

Duddingtonia flagrans is a nematode-trapping fungus responsible for attacking larval stages of helminths in pasture, which has potential as a biological control method. The aim of this study was to test the magnesium sulphate centrifugal flotation technique for the quantification of D. flagrans chlamydospores in sheep faeces and to verify their morphological viability. In this experiment one sheep received an oral dose of 4.5 x 10(6) chlamydospores/day during 20 days. Fecal samples were collected between days 15 and 20 and analyzed by the centrifugal flotation technique with magnesium sulphate. Densities of 1.23, 1.27 and 1.31gmL(-1) recovered 1.45 x 10(5), 3.87 x 10(5) and 1.65 x 10(5) chlamydospores from the faeces, respectively. Based upon the results it was concluded that this is an efficient technique for the chlamydospores quantification in ovine faeces. Moreover, it allowed more accurate visualization of chlamydospore morphology.

Susceptibility of Mice to Trypanosoma evansi Treated with Human Plasma Containing Different Concentrations of Apolipoprotein L-1

The aim of this study was to test the susceptibility of mice to Trypanosoma evansi treated with human plasma containing different concentrations of apolipoprotein L-1 (APOL1). For this experiment, a strain of T. evansi and human plasma (plasmas 1, 2, and 3) from 3 adult males clinically healthy were used. In vivo test used 50 mice divided in 5 groups (A to E) with 10 animals in each group. Animals of groups B to E were infected, and then treated with 0.2 ml of human plasma in the following outline: negative control (A), positive control (B), treatment with plasma 1 (C), treatment with plasma 2 (D), and treatment with plasma 3 (E). Mice treated with human plasma showed an increase in longevity of 40.9±0.3 (C), 20±9.0 (D) and 35.6±9.3 (E) days compared to the control group (B) which was 4.3±0.5 days. The number of surviving mice and free of the parasite (blood smear and PCR negative) at the end of the experiment was 90%, 0%, and 60% for groups C, D, and E, respectively. The quantification of APOL1 was performed due to the large difference in the treatments that differed in the source plasma. In plasmas 1, 2, and 3 was detected the concentration of 194, 99, and 115 mg/dl of APOL1, respectively. However, we believe that this difference in the treatment efficiency is related to the level of APOL1 in plasmas.

Levels of liver enzymes and urea in rats naturally infected with larval forms of Taenia taeniformis

The aim of this study was to investigate the changes in the levels of liver enzymes and urea associated with an outbreak of cysticercosis (Taenia taeniformis) in rat liver. At the end of a previous trial, the animals were euthanized and necropsied when cysts of T. taeniformis were found. The number of cysts ranged from ten to 30 per rat liver. Blood samples were collected from ten rats with cysticercoids (from 12 to 22 cysts) and from ten non-affected rats that were kept in another animal house. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and urea values were reduced when compared with non-parasitized animals; alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT) values were increased. Since the current experiment had to be repeated due to hepatic impairment evidenced by reduced ALT, AST, and urea values and increased ALP and GGT values, this study aims to alert the scientific community to the importance of sanitary barriers in animal housing.

The pathogenicity of a strain of Trypanosoma evansi in rats inoculated with the parasite in fresh and cryopreserved blood.

This study aimed to evaluate the Trypanosoma evansi strain pathogenicity (LPV-2005) in rats under passive immunity influence, of different concentrations and media preservation. Thirty six adult female Rattus norvergicus were separated in six equal groups. Groups A and B were inoculated with 105 T. evansi and groups C and D with 106 blood trypomastigotes per animal. Groups E and F were used as negative control in which the animals were inoculated with fresh and cryopreserved blood, without the parasite. Group A were composed of T. evansi infected born rats and cured females. Groups B, C and D were composed with animals never exposed to the LPV-2005 strain. All groups B and C animals received different doses of blood trypomastigotes kept in Wistar rats, while animals from group D were infected with cryopreserved blood kept in liquid nitrogen. The the strain pathogenicity was estimated by prepatency evaluation period, levels of parasitemia and animals longevity. Group D showed a longer prepatency period in comparison with other groups. The longevity of group D (27.8 days) was significantly different (P<0.05) from group C (4.8 days). Rats of the control group were euthanized 50 days postinfection. In conclusion, the tested inoculum-preservation methods and the infective dose of T. evansi influenced the pathogenicity of the LPV-2005 strain in rats. The presence of maternal antibodies did not prevent the infection and mortality of the rats by T. evansi.