Ultrastructural intestinal pathology induced by human Blasocystis in experimentally infected mice

Blastocystis spp. is a single-celled anaerobic enteric parasite that inhabits the lower gastrointestinal tract of humans and many animals. This emerging parasite with a worldwide distribution is often identified as the most common eukaryotic organism reported in human fecal samples that showed a dramatic increase in recent years; however its pathogenicity still shows many contradictions. To evaluate the histological and ultrastructural pathological changes induced by human Blastocystis isolates in the intestine of experimental infected mice. Fecal samples positive for Blastocystis were collected from patients, and processed for culture using Jones' medium. Cultured samples were subjected to examination by light and transmission electron microscopy. Blastocystis cyst stages were isolated and orally fed to immunocompetent BALB/c mice. Mice were sacrificed 2 weeks post infection. Semi-thin and ultra-thin sections prepared from their intestine were examined by both light and transmission electron microscopy [TEM], respectively. Blastocystis showed different forms: vacuolar, granular, amoeboid and cysts within 24 hours in culture. Histological examination of infected intestine showed vacuolar, granular and amoeboid forms in the caecum, but only cyst forms were observed in the colon. Intense inflammatory cell infiltration, edematous lamina propria, and villous atrophy were noticed. Ultrastructure of Blastocystis hominis by TEM revealed the surface coat with outer fibrillar layer, nuclei with multiple chromatin masses, and mitochondria with some pathological tubular changes. Atrophy and sloughing of microvilli of infected intestine was noticed in comparison to the mucosa of control non-infected mice that showed normal brush border and microvilli. Infection with Blastocystis may be self limited in some hosts however it may cause considerable pathological changes such as enterocytes invasion and intestinal mucosal atrophy of infected mice. Blastocystis mitochondrial vacuolations were detected within intestine of infected mice compared to culture forms. Thus, apparently B. hominis is capable of causing pathogenicity

Parasite Platelet Interactions

Platelets are not true cells. They are actually fragments of large bone marrow cells called megakaryocytes. They are small sized diskettes about 3 micro m in diameter, that on the whole amount to a mean measure of roughly 300,000 cells per micro l of blood. Individually, each features a cell of 7 fl, and a mean surface area of 8micro m2. In aggregate, blood platelets display a larger total volume and surface area than the aggregate of all other leukocyte subtypes taken together. Platelets are often classed as blood cells[1,2], and undoubtedly, play an eminent role in hemostasis and thrombosis. However, a recent research showed that platelets help to fight infections, by means that clearly exceed an exclusive function as mere players in the primary physiological processes[3]. On activation, platelets exhibit the ability to release considerable quantities of secretory products and express a multitude of immune receptors on their membrane. They are characterized by an open canalicular system, which contributes to the engulfment and/or filtration of serum components, pathogens or antigens[4]. The identification of chemokines in blood platelets has strengthened the view of these cells as participants in immune host defense. Platelet chemokines, representing pre-stored and rapidly releasable proteins, may play a major role as first-line inflammatory mediators. This is evident from their capability to recruit early inflammatory cells such as neutrophil granulocytes and monocytes and even to exhibit direct antimicrobial activity. However, insight is growing that platelet chemokines may also be long-term regulators, e.g., by activating T lymphocytes[5]. Regarding parasitic infections, blood platelets are suggested to have a role in destroying parasites. This finding may have an implication in treatment of parasites[6]. This review is an attempt to clarify the role of platelets in some parasitic infections

Evaluation of the OSOM Trichomonas rapid test for detection of Trichomoniasis vaginalis

Trichomoniasis is estimated to be the most widely prevalent non viral sexually transmitted infection in the world. Wet mount [WM] microscopy is the most common diagnostic method although its sensitivity is not satisfactory. The aim of the present study is to compare the diagnostic value of OSOM Trichomonas rapid test [OSOM Trich] with conventional diagnostic techniques and PCR for T. vaginalis infection. 128 samples were collected from symptomatic females. Samples were subjected to WM examination, culture, PCR and OSOM Trich test [an immunochromatography based test] for the detection of T. vaginalis. Of the 128 examined samples, PCR detected 14 positive samples, culture detected 13 samples, WM detected 9 samples, while OSOM Trich detected 12 of the PCR positive samples plus one false positive case. Sensitivity of culture, WM and OSOM Trich were 92.9%, 64.3% and 85.7% respectively, while specificity was 100%, 100% and 99.1%, respectively. OSOM Trich showed slightly lower sensitivity and specificity than culture, yet proved simple, rapid with no need for an equipped laboratory or a trained technician. The test is also economically acceptable, it can be used as a spot routine testing method for improving detection of T. vaginalis cases