Pulsed field gel electrophoresis of intact chromosomes of Babesia caballi revealed 4 chromosomes in the genome. The genome size of B. caballi was estimated to be 8.9 megabase (Mb). The sizes of chromosomes 1, 2, 3 and 4 were estimated to be 0.9, 1.1, 2.8 and 4.1 Mb, respectively. The bc48 rhoptry gene probe, derived from B. caballi, hybridized only to chromosome 3 (2.8 Mb).
Serum enzyme and electrolyte changes associated with Gambian trypanosomosis (sleeping sickness) were studied in vervet monkeys infected with Trypanosoma brucei gambiense.
Although Serum aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) concentrations of the monkeys increased at various points after infection, the levels of alkaline phosphates (AP) decreased. Similarly, serum sodium and potassium levels increased while those of calcium and phosphate decreased. These changes suggested that hepatic, renal and parathyroid damage are some of the pathological features of Gambian sleeping sickness in man leading to early death of untreated persons.
Changes of serum interleukin-12 (IL-12) level and splenic helper T cell (Th cell) subpopulation were examined in the early phase of inoculation with Babesia rodhaini in mice preimmunized with B. microti. Only slight increase of the percentage in parasitized red blood cell was observed in B. rodhaini inoculated preimmunized mice. Serum IL-12 level significantly increased from 6 hr with a peak at 12 hr after the inoculation. In addition, the mice showed a differentiation of helper T cell type 1 (Th 1 cell) and the suppression of helper T cell type 2 in splenic Th cells on day 3 after the inoculation. These results suggested that IL-12 produced in the early phase of infection induced the differentiation of Th 1 cell, by which cellular protective immunity enhanced against Babesia rodhaini infection in preimmunized mice.
Serum Interleukin-12 (IL-12) levels were measured in B. microti and B. rodhaini inoculated mice, since it is well known as an early responsible cytokine to induce the differentiation of helper T cell (Th cell) into helper T cell type 1 (Th 1 cell). Serum IL-12 levels in B. microti inoculated mice revealed two significant peaks at 3 and 24 hr after inoculation, while no significant change was observed in B. rodhaini inoculated mice. From our previous report, Th 1 cell and helper T cell type 2 (Th 2 cell) was predominant in splenic Th cells of mice on 5 day after inoculation with B. microti and with B. rodhaini, respectively. Interleukin-12 might initiate the differentiation of splenic Th 1 cell in the early phase of infection in mice infected with B. microti and closely related to the host protective cellular immunity.
The present study demonstrated the inhibitory effect of fucoidan, a class of polysaccharides mainly constituted of sulfated L-fucose, on the in vitro growth of Babesia bovis in a dose-dependent manner, as determined by light microscopy. The 50% inhibitory concentration of fucoidan was determined to be 123 µg/ml. The results obtained in this study suggested that fucoidan is a potential chemotherapeutic against babesiosis, although the exact mechanisms of its inhibition require further studies.