Effect of alginate nanoparticles on the immunogenicity of excretory-secretory antigens against acute toxoplasmosis in murine model.

Efficacy of alginate nanoparticles (Alg-NPs) as vaccine delivery for the excretory-secretory antigens (ESAs) against the virulent strain of Toxoplasma gondii was evaluated. Swiss albino mice were intraperitoneally immunized with three doses of either in vivo and in vitro-prepared ESA vaccines, 20 µg each, at 2-week intervals, then were challenged with 2500 tachyzoites of the RH HXGPRT (-) Toxoplasma gondii strain, four weeks later. Mice mortality, tachyzoite number in both peritoneal fluid and impression smear, and viability, ultrastructural tachyzoite changes, measuring immunological markers, and histopathological changes of both liver and spleen were studied, in comparison to alum adjuvanted ESAs and infected control subgroups. The in vivo-prepared Alg-NPs loaded ESAs vaccinated subgroups induced significant reduction in mice mortality, tachyzoite count in both peritoneal fluid and impression smears and viability. Scanning electron microscopy revealed tachyzoites deformities with multiple irregularities, while transmission electron microscopy showed tachyzoites distortion, disrupted plasma membranes, loss of nuclear integrities, and absence of dense granules with extensive vacuolations. A statistically significant increase in the level of both IFN-γ and anti-Toxoplasma IgG was noted. Histopathological results recorded amelioration of the pathological changes induced by Toxoplasma infection in both liver and spleen, with scanty parasites. Therefore, Alg-NPs proved its effectiveness in enhancing the ESAs antigencity, and recommended to test its potentiality as drugs carrier for anti-Toxoplasma agents to enhance their therapeutic efficacy.

Influence of temperature and salinity on the viability and infectivity of Giardia lamblia and Cryptosporidia parvum.

The present work was designed to assess the effect of different degrees of temperature and salinity on the viability and infectivity of G. lamblia and C. parvum at different storage time. The results revealed that boiling of protozoa for one minute minimized their viability to less than 1% and rendered them non-infectious, while exposure to 4 degrees C and -4 degrees C up to seven days preserved their viability and infectivity. Whereas it was found that salinity was effective at high concentration (50 ppt) or for long storage time at lower concentrations.

Co-agglutination (Co-A): a rapid test for the diagnosis of experimental trichinellosis.

Co-agglutination test (Co-A test) which has a wide application spectrum in bacterial diseases has been used for the detection of some parasitic infections. This work was to evaluate Co-A test as a new diagnostic tool in detection of T. spiralis antigens in both sera and urine of experimentally infected mice as compared with ELISA, for the diagnosis of trichinellosis. The results obtained by Co-A test were closely correlated with those of ELISA. The most important was that both tests were capable to detect T. spiralis antigen in urine of light and heavily infected mice only at the 30th days post infection. So, Co-A is an accurate, easy and rapid test that can be used on large scales for diagnosis of trichinellosis.