Diagnosis of toxoplasmosis in immunosuppressed mice using the polymerase chain reaction (PCR) and the enzyme linked immuno-sorbent assay (ELISA) techniques.

In the present study, Toxoplasma infection with the virulent and avirulent strains in both immunocompetent and immunosuppressed mice was diagnosed using the MDS ELISA for detection of CA in sera and the PCR for demonstration of DNA in livers, brains and mononuclear cells of blood. Both techniques proved to be convenient, especially in immunosuppressed mice.

Serum IgG antibody response to Pneumocystis carinii among immunosuppressed, malnourished and healthy rats.

Pneumocystis carinii is an important opportunistic pulmonary pathogen that causing pneumonia in premature infants, children with immunodeficiency diseases and patients of all ages receiving immunosuppressive agents. In this work, humoral immune responses to this organism were studied, using IFAT during the period of infection and recovery of immunosuppressed and malnourished rats compared to healthy group. Where sever pneumonitis similar to that seen in humans can be induced in this experimental model. Serum IgG antibody titers to the organism were absent in rats administered corticosteroids but rose after steroid tapering with disappearance of the organism from their lungs due to reactivation of the immune system. While in malnourished infected rats, clearance of the organism had occurred after regaining the protein diet with progressive increase in IgG level denoting their immunocompetent state. IgG antibody appeared in the serum of control healthy rats with the progress of age at low non diagnostic level indicating the presence of dormant parasites in their lungs.

Opportunistic intestinal protozoa in chronic diarrhoeic immunosuppressed patients.

Chronic diarrhoea accompanied by weight loss is a common and often debilitating problem in immunocompromized patients, receiving chemotherapeutic agents. In these patients, the intestinal opportunistic parasites probably played a major role in causing this clinical manifestation. The present work, aims to search for these parasites. Special stains for each parasite were used to differentiate it easily from the fecal elements, obviating the need for diagnostic invasive techniques especially used in microsporidial infection. The detected parasites were, Giardia lamblia (17.7%) best seen by iron haematoxylin stain. Coccidian oocysts (Cryptosporidia; 13.3% Isospora belli; 2.2%) were clearly seen by using Ziehl-Neelsen and Chromotrope-based stains. The Gram positive spores of Enterocytozoon bieneusi were (4.4%) and best seen by using chromotrope-based stain, where as Giemsa failed in their diagnosis.

Effect of toxoplasmosis on experimental schistosomiasis.

One hundred and twenty Swiss albino mice were infected with avirulent strain of Toxoplasma gondii (Czechoslovakian strain) challenged with Schistosoma mansoni at different intervals of one week, one month, and two months. Worm load, egg count, oogram pattern and liver and spleen weight were assessed for each mouse. Toxoplasmosis induced a significant resistance to Schistosoma mansoni challenge infection as evidenced by the reduction in worm load, egg count and changes in oogram pattern. The mean liver weights of concomitantly infected mice was increased which was not significantly different from their corresponding Schistosoma infected controls but the increase in spleen weight was significant.

Pneumocystis carinii: recognition of the infection in albino rats using different stains.

Pneumocystis carinii is a commensal protozoan which may cause pneumonia in hosts with compromised immune status and may end fatally. Since effective management of pneumocystic pneumonia depends on rapid and accurate recognition of the disease, so, the present study aims to throw lights on the best staining method for cytodiagnosis of this organism with the sequential pathological changes in the infected lungs. An immunosuppression state was induced in albino rats for 6-8 weeks then rats were sacrificed weekly & lungs were examined for infection using different stains. In stained smears, intracystic bodies have been identified using Giemsa, Papanicolaou & Toluidine blue stains. On the other hand, cysts were inspected in paraffin sections using Gomori methenamine silver nitrate (GMS) & weight gram stains. Histopathologically, in sections stained with H & E, features of Pneumocystis carinii pneumonia were obvious, foamy exudation, inflammatory infiltration formed mainly of histiocytes, plasma cells, lymphocytes, thickening of alveolar septa and lastly formation of hyaline membrane in some alveoli.

Seroprevalence of Toxoplasma and cytomegalovirus in complicated pregnancies.

Anti-Toxoplasma and anti-cytomegalovirus (CMV) antibodies were sought in 200 pregnant women (100 with complicated pregnancies and 100 matched controls without any hazards) by ELISA test. Sixty-five per cent of the women with complicated pregnancies had Toxoplasma antibodies, while 51% had CMV antibodies. Toxoplasma seroprevalence alone was higher in women with intrauterine foetal death (IUFD) (80%). CMV seroprevalence alone was higher in women with premature labour (44.4%) and women with stillbirth (40%). Seroprevalence of both Toxoplasma and CMV was clearly higher in women with abortion (55.7%). Seroprevalence of Toxoplasma and CMV in the control group was 6% and 30%, respectively. These data confirm that Toxoplasma and CMV are important causes of complicated pregnancy.

A study on experimental cryptosporidiosis.

Cryptosporidium oocysts were isolated from stools of infected patients diagnosed as cryptosporidiosis. Suckling Swiss albino mice were infected orally by these oocysts in a dose of 10(6) oocysts/mouse. Mice were divided into 9 groups according to the duration of infection 2, 3, 4, 5, 6, 7, 10, 10, 15, 21 days postinfection, corresponding non infected control groups were included. Stools of infected mice were examined twice daily to determine; infection rate, prepatent period and intensity of infection. Mice were sacrificed according to the schedule and the whole intestine was isolated and processed for histopathological examination by H & E and modified Ziehl Nielsen stain, and histochemical examination for acid and alkaline phosphatase activity. The results revealed that the infection rate was 90% and prepatent period 3-5 days and the course of infection was 21 days. The maximum pathological changes were in the ileum. These changes were reversible.

Gastro-vascular and micro-vascular changes in chronic murine schistosomiasis mansoni-response to propranolol.

Histopathologic study of the gastric wall of mice infected with Schistosoma mansoni was carried out at 8, 12, 16 and 20 weeks post-infection (p.i.). The gastric vascular structures were more sensitive to injury with the progression of liver disease than the glandular cells, with marked submucosal edema and thickening of submucosal and subserosal vessels. By transmission electron microscopy, the mucosal microvessels had thickened basement membrane and conspicuous endothelial cells with granular cytoplasm thrown into numerous intraluminal microprojections and with increased number and size of pinocytotic vesicles. When propranolol was administered orally as 20 mg/kg daily doses for two weeks at 6, 10, 14 and 18 weeks p.i., a striking regression of gastro vascular and micro-vascular changes has been observed, particularly with early drug therapy. Based on the present study, it can be concluded that "structural autoregulation" of gastric vasculature to the emerging portal hypertension in chronic murine schistosomiasis mansoni, is a dynamic process that could be reversed by propranolol therapy. This response could, possibly, improve gastric mucosal perfusion and functional abnormalities which may predispose the gastric mucosa to severe damage or hemorrhage.

Effect of Capillaria hepatica infection on Schistosoma mansoni challenge in mice.

The combined infection between Capillaria hepatica and Schistosoma mansoni was studied. The results of this work revealed that C. hepatica infection induced significant reduction of S. mansoni worm load in the two groups infected with C. hepatica and challenged with S. mansoni either during worm maturation period of C. hepatica, or at the time of presence of C. hepatica eggs in the liver Reduction in total and tissue egg count was also reported, but eggs excreted in the stool showed no difference in count from that of S. mansoni-infected controls. Oogram pattern of the experimental groups revealed a higher percentage of dead eggs and absence of mature and some developing stages. Scanning electron microscopy demonstrated severe destruction of adult worm of both groups. All these data showed the vigorous destructive effect of C. hepatica infection on the challenged S. mansoni.

Schistosomal nephropathy: effect of ciclosporin A (CsA) in murine schistosomiasis mansoni.

The effect of cyclosporin A (CsA) on schistosomal nephropathy in infected mice with Schistosoma mansoni (S. Mansoni) has been investigated. Infected mice were orally treated with 50 mg/kg body weight of CsA for 5 consecutive days at the 8th, 12th, 16th week postinfection (p.i.). Four weeks after drug therapy, CsA aborted and retarded the progression of glomerular injury in all stages of the disease; particularly with early drug therapy. This was evidenced by the reduction in electron dense deposits and weak positivity by fluorescent microscope. This response was accompanied by amelioration of hepatosplenomegaly. The effects of CsA could be related to its known immunosuppressive effect on T-helper (Th) cells. Moreover, CsA had a profound anti-schistosomal activity as demonstrated by the significant decrease in worm burden specially female worms, and the increase in the percentage of mature and dead eggs in intestinal mucosa in this study. So, CsA would ameliorate the glomerular lesion in early stages of schistosomal nephropathy, mainly by its immunosuppressive effect, but in later stages, the direct anti-schistosomicidal effect would take the upper hand.