20 research outputs found
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Detection and genotypic characterization of Toxoplasma gondii DNA within the milk of Mongolian livestock
Toxoplasma gondii is a global, zoonotic parasite capable of infecting any warm-blooded host. Toxoplasmosis can cause a variety of illnesses including abortions and congenital defects in humans, sheep, and goats. Congenital toxoplasmosis is considered to have the highest global disease burden of any foodborne illness in humans. This study examined the potential role of milk as a route of T. gondii transmission between livestock and humans within Mongolian herders, a little-studied population which relies heavily on animals. Milk of Mongolian sheep, goats and Bactrian camels was tested for the presence of T. gondii DNA, and a survey was conducted to ascertain what behavioral and environmental factors were present that might potentiate T. gondii infection within these Mongolian communities. T. gondii DNA was detected in samples from one sheep and five camels. Sequence analysis of DNA from camel milk revealed that two were from potentially virulent T. gondii genotypes. This has implications for public health in the region, as milk is an extremely important source of nutrition and our survey results imply that some people believe consumption of raw camel milk carries health benefits. This is the first report of T. gondii DNA in Bactrian camel milk as well as the first genotypic characterization of T. gondii within Mongolia
Lymphocytes and Macrophages Are Infected by Theileria equi, but T Cells and B Cells Are Not Required to Establish Infection In Vivo
Theileria equi
has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike
Theileria spp
. that infect cattle (
Theileria parva
and
Theileria annulata
), the intraleukocyte stage (schizont) of
Theileria equi
does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology,
Theileria equi
has been reported to infect lymphocytes
in vivo
and
in vitro
, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in
Theileria equi
pathogenesis, peripheral blood mononuclear cells were infected
in vitro
and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of
Theileria equi
was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection
in vivo
, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with
Theileria equi
sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the
Theileria equi
life cycle
in vivo
. These findings suggest that the factors mediating
Theileria equi
leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for
Theileria annulata
and
Theileria parva
. These data will greatly facilitate future investigation into the relationships between
Theileria equi
leukocyte tropism and pathogenesis, breed susceptibility, and strain virulence
Protective Effects of Passively Transferred Merozoite-Specific Antibodies against Theileria equi in Horses with Severe Combined Immunodeficiency
Theileria equi
immune plasma was infused into young horses (foals) with severe combined immunodeficiency. Although all foals became infected following intravenous challenge with homologous
T. equi
merozoite stabilate, delayed time to peak parasitemia occurred. Protective effects were associated with a predominance of passively transferred merozoite-specific IgG3