الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Toxoplasma gondii is an obligate intracellular protozoon, which affects about
30% of the population all over the world. Although it is considered to be one of the
most widespread disease agents, clinical diseases caused by this parasite are not
common, since the majority of infected persons remain asymptomatic latent infection.
Toxoplasma is a zoonotic infection, where the definite host belongs to the feline
family, whereas humans and other warm-blooded animal are intermediate hosts. It is
considered to be one the opportunistic parasites and can be transmitted by a variety of
modes. Toxoplasma gondii oocysts shed by the feline host can be acquired by ingestion
of contaminated food and water. In addition, meat can also constitute a source of
infection, if it contains tissue cysts. Other infection routes include organ transplantation,
blood transfusion and congenital transmission from mother to fetus. Toxoplasmosis
exists mainly in its latent form, with reactivation of infection occurring in immunecompromised
persons, since Toxoplasma gondii is an opportunistic parasite. Acute
toxoplasmosis is often underdiagnosed due to the ambiguity of clinical symptoms such
as lymphadenits and sore throat. Congenital toxoplasmosis presents with more serious
ocular and neurological disorders.
Since Toxoplasma gondii is an intracellular parasite, it reaches many body
systems and has a wide range of effects on host physiological functions, such as
endocrine balance. An example for hormonal alterations in seropositive toxoplasmosis
patients is the activation of hypothalamic pituitary adrenal (HPA) axis and
subsequently, an increase in glucocorticoid concentration. In addition, elevated
testosterone, prolactin levels have been found in Toxoplasma seropositive patients.
Prolactin which is a hormone released from the anterior pituitary (under the
inhibitory control of dopamine) plays a major role in the lactation, regulation of
reproductive functions, growth. Prolactin receptors are well expressed in the adrenal
glands. In cases of hyperprolactinemia, adrenal androgens are secreted in an increased
manner and contribute to the rapid formation of acne vulgaris and progress of
androgenic alopecia.
This wide spectrum of physiological alterations observed concomitantly with
toxoplasmosis suggests the possible involvement of this protozoal infection in
multifactorial disorders related to endocrine alterations. Such as acne vulgaris and
androgenic alopecia. Acne vulgaris is an inflammatory skin condition appearing in
adolescence and may continue to older age groups. Sebum production, which plays a
pivotal role in acne formation, is under hormonal control, since sebaceous glands harbor
androgen receptors for testosterone. Since the skin displays its own peripheral HPA
axis. Sebocytes express corticotrophin releasing hormone (CRH) receptors and CRH
has been found to promote lipogenesis by these cells