Experimental Infection by Trypanosoma evansi in Rabbits: Levels of Sodium, Potassium, Calcium and Phosphorus in Serum
Acta Scientiae Veterinariae
Experimental Infection by Trypanosoma evansi in Rabbits: Levels of Sodium, Potassium, Calcium and Phosphorus in Serum
Autor Correspondente: Aleksandro Schafer da Silva | [email protected]
Palavras-chave: trypanosomosis, trypanosoma evansi, minerals, rabbit, chronic infection
Resumos Cadastrados
Resumo Inglês:
Background: Trypanosoma evansi is the most widely distributed of the pathogenic African animal trypanosomes, affecting
domestic livestock and wildlife in country. The animals presented clinical sings as anemia, emaciation, apathy, recurrent fever,
enlarged lymph nodes, edema and abortion The minerals have different functions in the organism, and an imbalance, either by
excess or deficiency, or a pathological condition, causes alterations in the respective serum levels, as well as in trypanosomosis.
Therefore, the aim of this study was to evaluate the concentrations of sodium, potassium, calcium and phosphorus in blood
serum of rabbits experimentally infected with Trypanosoma evansi.
Materials, Methods & Results: Twelve adult female Oryctolagus cuniculus, weighing average 3.9 kg, were used. Rabbits were
divided into two groups, a control group with six animals (rabbits 1-6) and an infected group with six animals (rabbits 7-12).
Animals from trypanosome-infected groups were inoculated intraperitoneally with 0.5 mL of rat blood containing 108 trypanosomes
(Day 1). Control group received physiological solution by the same route. Parasitemia was estimated daily for 118 days postinoculation
(PI) by microscopic examination of smears. Blood samples for hematology and evaluation of serum minerals were
collected at days 1, 5, 20, 35, 50, 80 and 118 PI. Hematocrit was evaluated for monitoring of the disease. Inductively coupled
plasma optical emission spectrometry (ICP OES) was used to measure the levels of sodium, potassium, calcium and phosphorus.
Hyporexia, edema and fever were clinical signs associated with change in the levels of the minerals. A decrease in the number of
red blood cells was only observed at day 5 post-inoculation. Significant differences were observed among groups (P < 0.05) in
minerals levels. Sodium and calcium were reduced at days 35, 50, 80 and 118 PI. The concentration of potassium was decreased
at days 20, 35 and 50 PI, while phosphorus was only at day 35 PI. Interestingly, all minerals were reduced in serum at day 35 PI,
where all infected rabbits had edema of the eyelids and ears.
Discussion: Changes in the circulating levels of sodium, potassium, calcium and phosphorus where observed when all the
rabbits showed clinical signs of the disease. Alteration in the concentrations these minerals of were reported in cattle, equines,
camels and humans infected with trypanosomatids, although the cause of these changes was not fully elucidated. According to
the literature data, differences in concentration of macro minerals have been found among species of trypanosomes and the
specific host involved. In other study, researchers reported decreased levels of iron and zinc and increased copper in T. evansiinfected
cats, which were correlated with anemia, lymphopenia and inflammatory response. This study the reduction in sodium
and potassium may have contributed to the edema in the rabbits. As calcium is essential for the life of trypanosomes, these
parasites have adapted to store calcium, what might explain the reduction of the mineral in the blood of the rabbits. The reduction
of phosphorus might have been due to hyporexia presented by the rabbits, with consequent lower intake of phosphorus. Based
on the results, it was concluded that the infection by Trypanosoma evansi influences the serum levels of sodium, potassium,
calcium and phosphorus in rabbits. The severity of clinical signs can varied among the infected rabbits.
