Axenic growth in vitro of Ancylostoma duodenale to the filariform (resting) larvae.

Large numbers of free-living stages of Ancylostoma duodenale can be grown in vitro on formalin-killed Escherichia coli supplemented with cholesterol and Dulbecco's minimum essential medium (DMEN). Eggs at 28 degrees C hatched and released first-stage larvae in 24 hr. First-stage larvae molted in 36 hr. at 28 degrees C. Second-stage larvae, molted in 2-3 days at 28 degrees C, but retained the old cuticle. Third-stage larvae characterized by the presence of a buccal cap capsule; sheath; filariform esophagus and absence of lips. Lateral alae were observed in all free-living stages.

Antibodies against some zoonotic parasites in commensal rodents trapped from Dakahlia Governorate, Egypt.

A sero-survey for antibodies against leishmaniasis, toxoplasmosis, amoebiasis and schistosomiasis was carried out among four commensal rodents (R. norvegicus, R. rattus, M. musculus and A. cahirinus) trapped from different areas in Dakahlia Governorate. The results showed different rates of antibodies as indicated by the indirect haemagglutination tests. The percentage of seropositive reactions was 8.6 for leishmaniasis, 11.6 for toxoplasmosis, 8.8 for amoebiasis and 5.03 for schistosomiasis. The role played by these rodents as reservoir hosts of zoonotic parasites were discussed.

Some histopathological and histochemical aspects of human ancylostomiasis.

Using Watson's intestinal capsule small intestinal mucosal biopsies were taken from 30 patients with parasitologically proved pure ancylostomiasis and 12 normal controls. Biopsies were examined pathologically and histochemically for the enzymes, Alkaline phosphatase, succinic dehydrogenase, non specific esterases and acid phosphatase. The study revealed normal histological as well as normal enzymatic activity of the intestinal mucosa.

Evaluation of immunodiagnostic tests in detection of trichinosis in experimentally infected rats.

The enzyme-linked immunosorbent assay (ELISA), the indirect immunofluorescent (IF) and the counter current immunoelectrophoresis (CEP) were evaluated in detection of anti-Trichinella antibodies in experimentally infected rats. The CEP was the most specific and highly sensitive test. Also, the IF was highly sensitive but less specific. ELISA was the least specific but extremely sensitive specially in detecting early infection.

Ultra structure study of schistosomula recovered after cercarial penetration of isolated skin.

The ultrastructure, development and antigenic nature of the surface and the viability of schistosomula formed after cercariae had penetrated isolated skin has been studied. Within 2 hours of transformation, the surface membrane of schistosomula had changed from trilaminate to heptalaminate structures and lost their cercarial glycocalyx. The preacetabular glands of schistosomula were emptied, the mixed agglutination reaction demonstrated the presence of human A and B blood group-like antigenic determinant on approximately 30% of 3 hours old schistosomula. The first schistosomula reached the gut closed stage by day 12 (50-70%), and between 40% of all schistosomula developed to maturity when injected intravenously into mice.

The mechanism of acquired immunity in experimental giardiasis.

Giardia-spontaneously cured mice were rendered resistant to challenge infection. This was documented by the decreased cyst excretion rate comparable to the control ones. Endoxan and irradiation treatment caused a breakdown in both humoral and cellular immunity. Immune-depressed mice were more susceptible to Giardia infection, thus proving the active role of antibodies and cell-mediated immune response in giardiasis.

Detection of Giardia lamblia copro-antigens by enzyme-linked immunosorbent assay and counterimmunoelectrophoresis.

The enzyme-linked immunosorbent assay (ELISA) and counter-immunoelectrophoresis (CIEP) were used to detect G. Lamblia Copro-antigens. Rabbit antisera raised against Giardia trophozoites and cysts were used as anti-Giardia antibodies. The overall sensitivity of the ELISA was 96.15% and its specificity was 93.48% in contrast to 69.23% and 82.61% for the CIEP.

Virulence of Giardia lamblia isolates to laboratory mice.

Laboratory breed albino mice free of G. muris infection were inoculated with G. lamblia cysts isolated from the stools of patients with different clinical manifestations, symptomatic diarrhoeic, symptomatic non-diarrhoeic and asymptomatic cyst carriers. The virulence of various isolates was assessed by cyst excretion rate in the stools, trophozoite counts in the duodenum and histopathological lesions of jejunal mucosa. A marked variation in the virulence of cysts obtained from the 3 groups of patients was proved.

Fresh water malacologic fauna in Dakahlia Governorate.

Ten snail species representing the snail fauna in Dakahlia were identified as P. acuta, B. unicolor, L. carinatus, Cleopatra species, B. alexandrina, M. tuberculatus, H. duryi, B. truncatus, N. nilotica and L. caillaudi. The density of snail population has had a major peak at July and August while a minor peak was found at the winter closure period during the winter months.

Histopathological and histochemical studies on experimentally infected hamsters with Stictodora tridactyla.

Histopathological changes in the intestinal mucosa in the form of inflammation with atrophic changes in the villi and foci of cellular reaction were seen at the sites of experimental infection in hamsters with Stictodora tridactyla. The activity of succinic dehydrogenase, non specific esterase and alkaline phosphatase enzymes in the villi and the activity of acid phosphatase in the glands were markedly reduced. These changes suggest a disturbance in both digestive and absorptive mechanisms of the small intestine.

Immunodiagnosis of bancroftian filariasis.

The indirect fluorescent antibody test, the enzyme-linked immuno sorbent assay and the indirect haemagglutination test were evaluated in immunodiagnosis of bancroftian filariasis using W. bancrofti microfilarial antigens. The tests gave a higher positive reactions with microfilaraemic, clinical filarial and endemic normal sera respectively. Non-specific cross-reactions were common in the three tests, so immunodiagnosis should be preceded by stool examination. IFAT gave the highest sensitivity and specificity, while IHAT was the least one. ELISA is simple, sensitive and can be used in seroepidemiological studies.

Immunodiffusion, immunofluorescence and enzyme-linked immunosorbent assay in the serodiagnosis of giardiasis.

Circulating anti-Giardia lamblia antibodies have been estimated in the sera of 48 patients of parasitologically proven G. lamblia infection using the immunodiffusion (I.D.) indirect fluorescent antibody (I.F.A.) and enzyme-linked immunosorbent assay (ELISA) tests. The results showed that ELISA technique was the most simple, sensitive (95.8%) and specific (100%) test. These advantages make it more applicable in seroepidemiology of giardiasis.