Toxoplasma infect ion is c o m m o n in m a n and animals, ye t for 60 years the life cycle of Toxoplasma gondii remained unknown. Recen t ly a new form of Toxoplasma was found in the feces of cats t ha t had ea ten Toxoplasma-infected mice (for rev iew of earlier work see [1]). Th is fecal form is biological ly different f rom the known stages of Toxoplasma. While searching the feces of cats f...

Plasmodium sporozoites develop within oocysts residing in the mosquito midgut. Mature sporozoites exit the oocysts, enter the hemolymph, and invade the salivary glands. The circumsporozoite (CS) protein is the major surface protein of salivary gland and oocyst sporozoites. It is also found on the oocyst plasma membrane and on the inner surface of the oocyst capsule. CS protein contains a conser...

The value of protozoa in investigations of nucleocytoplasmic relationships has long been appreciated, as indicated by reviews (1, 3, 7) of the extensive literature on this subject. Though the malarial parasite apparently has not previously been employed in such studies, we have found it to be a potentially useful organism in this regard. The elaborate differentiation that the parasite undergoes...

Cryptosporidium parvum and Giardia lamblia are protozoa capable of causing gastrointestinal diseases. Currently, these organisms are identified using immunofluorescent antibody (IFA)-based microscopy, and identification requires trained individuals for final confirmation. Since artificial neural networks (ANN) can provide an automated means of identification, thereby reducing human errors relat...

A survey of Isospora suis performed in 177 faecal samples from 30 swine farms detected thin wall type I. suis oocysts in seven samples. This type of oocyst measuring 23.9 by 20.7 microns had a retracted thin wall similar to that of the genus Sarcocystis. This type of oocysts, isolated from four different faecal samples, was inoculated in four-five-days-old piglets free of contamination in order...

Reduction of risk for human and food animal infection with Toxoplasma gondii is hampered by the lack of epidemiological data documenting the predominant routes of infection (oocyst vs. tissue cyst consumption) in horizontally transmitted toxoplasmosis. Existing serological assays can determine previous exposure to the parasite, but not the route of infection. We have used difference gel electro...

Considering that the current immunoassays are not able to distinguish the infective forms that cause Toxoplasma gondii infection, the present study was carried out to evaluate the reactivity of two recombinant proteins (CCp5A and OWP1) from oocyst/sporozoite, in order to differentiate infections occurring by ingestion of oocysts or tissue cysts. The reactivity of the recombinant proteins was as...

Crystalloids are transient organelles that form in developing malaria ookinetes and disappear after ookinete-to-oocyst transition. Their origins and functions remain poorly understood. The Plasmodium berghei scavenger receptor-like protein PbSR is essential for mosquito-to-host transmission of the parasite: PbSR knockout parasites produce normal numbers of oocysts that fail to form sporozoites,...

anopheles stephensi is one of the main vectors of malaria in the world including south of iran. three geographical populations for an. stephensi have been defined, based on egg morphology. the aim of the current study is determining the ability of different geographical populations of an. stephensi in the transmission of plasmodium berghei using anka strain of this parasite. four geographical p...

A small-volume sentinel chamber was developed to assess the effects of environmental stresses on survival of sucrose-Percoll-purified Cryptosporidium parvum oocysts in soil and animal wastes. Chambers were tested for their ability to equilibrate with external chemical and moisture conditions. Sentinel oocysts were then exposed to stresses of the external environment that affected their viabilit...