Ultrastructural characteristics of Babesia caballi in equine erythrocytes in vitro

Abstract

Babesia caballi cultured continuously in equine erythrocytes was examined by transmission electron microscopy. The use of cultured B. caballi permitted examination of a large number of parasitized cells with various stages of intra erythrocytic development. The piriform merozoites of B. caballi were composed of an outer membrane and an inner double-membrane complex. Numerous micronemes and three rhoptries were found in the pellicle of the merozoite, and a spherical body was seen in the anterior part of the merozoite which usually lay adjacent to the nucleus and the pellicle. These findings were similar to those for merozoites of bovine Babesia parasites such as B. bigemina. The trophozoites were surrounded by a single membrane, were continuously changing their body shape with extension and retraction of the pseudopod. A long pseudopod extended far into the host cell cytoplasm, and was finally completely enclosed in a cell, but did not have hemozoin pigment, the breakdown product of hemoglobin digestion.

Antibodies Raised against Bcvir15, an Extrachromosomal Double-Stranded RNA-Encoded Protein fromBabesia canis, Inhibit the In Vitro Growth of the Parasite

“…As part of a search for a homologous sequence from the P. falciparum Pf60 multigene family (8,9,11) in the agent of canine babesiosis in Europe, the anti-Pf60.1 antiserum (11) was used to perform an immunological screening of a B. canis (isolate A) cDNA library. The Bcvir cDNA (accession number AJ494862) was 1,115 nucleotides (nt) long, with a poly(A) 22 tail and with the translation initiation codon at position 61 (Fig. 1A).…”

“…This suggested that antibodies have to directly reach the protein Bcvir15 within the cytoplasm of B. canis. Babesia parasites are directly in contact with the cytoplasm of the erythrocyte during their erythrocytic life cycle, and in B. equi and B. caballi, a tubular structure connecting the erythrocyte membrane to parasite was observed and its ultrastructure was described (17,21,22). Although the function of these tubular structures remains unknown, it has been speculated that intraerythrocytic Babesia parasites come into direct contact with culture medium or host plasma and that these structures might play a role in the uptake of nutrients.…”

Blood parasite infection causing inflammatory reactions and benign formations in human thyroid gland

“…По мере развития заболевания газовый и энергетический обмен повышается, а коэффициент утилизации кислорода, отражающий степень окислительно-восстановительных процессов в тканях на высоте инвазии, снижается [10]. Появление пигмента гемосидерина объясняется депонированием мерозоитами гемоспоридий в своей протоплазме белка гемоглобина в качестве энергетического материала для нахождения в плазме крови, при внедрении в эндотелий сосудов и клетки паренхиматозных органов, где происходит шизогония [25]. Находящийся в мерозоитах белок гемоглобин, естественно, будет давать положительную реакцию на пигменты крови.…”

“…Было отмечено, что в теле мерозоитов Babesia caballi депонируется белок гемоглобин, который используется, вероятнее всего, для питания в период нахождения паразита в плазме крови [25]. Не исключается присутствие гемоглобина в теле мерозоита и после внедрения в клетки паренхиматозных органов.…”

Artemisinin and its derivatives in treating protozoan infections beyond malaria

“…In another study, it was reported that the single use of ART derivatives may only have low effectiveness, but the addition of lumefantrine to artemether may be effective for B. gibsoni infection [98]. Babesia parasites do not produce hemozoin nor contain food vacuoles [99]. The absence of these organelles in Barbesia spp.…”