Histocompatibility antigens in Egyptians with cutaneous leishmaniasis: a preliminary study.

The frequency of human leucocytic antigens (HLA) were studied in 27 patients with cutaneous leishmaniasis to evaluate the role of HLA antigens as genetic markers in the pathogenesis of this protozoal skin infection. A significant statistical association was observed between HLA-A11, -B5 and -B7 antigens and diffuse cutaneous leishmaniasis. In conclusion, study of immune response genes could be of value to understand the pathogenic mechanisms responsible for cutaneous leishmaniasis.

Transplacental transfer of schistosomal antigens and antibodies.

Circulating S. mansoni soluble antigens (CSA) and antibodies (CAB) were investigated in sera of 32 S. mansoni-infected pregnant mothers, their 32 newborns and 26 non-pregnant infected women. CSA levels in pregnant mothers and their newborns were significantly higher than in the 3rd group. Also, a significant positive correlation was detected between the CSA levels in sera from infected mothers and the cord blood of their newborns proving the transplacental transfer of these antigens. On the other hand, CAB levels were significantly higher in the 3rd group than in the mothers and their newborns and this could be explained by the immune complexes formation. No schistosome eggs or worms were detected in placentas and the possibility of congenital schistosomiasis was eliminated.

Dot-ELISA as a diagnostic test in hydatid disease.

Detection of circulating echinococcal antigens and antibodies were tried in 18 patients with hydatid disease and 32 healthy blood donors as controls using dot-ELISA. Hydatid cyst fluid antigen and anti-echinococcal hyperimmune rabbit sera were used for the detection of antibodies and antigens respectively. The results proved that this test is sensitive (88.9%), specific (96.9%) and rapid for detecting echinococcal antibodies. On the other hand, circulating antigens could be detected with 55.6% sensitivity. This low sensitivity was attributed to the small amounts of circulating antigens and/or immune complexes formation.

Detection of antitrichomonal antibodies in sera and cervical secretions in trichomoniasis.

The AT, IFAT and ELISA were used to detect circulating and cervical antitrichomonal antibodies, using living and dead whole parasite or soluble protein extract as antigens respectively, in 93 women with proven trichomoniasis and 25 healthy women as controls. The results revealed that the IFA test is the most sensitive one for detecting serum (92.5%) and cervical (87.1%) antibodies. Circulating IgM rather than IgG appeared to be the antibody class involved in infected women, while cervical secretions showed a significant high concentrations of IgA, IgG and IgM. On the other hand, no IgE was detected neither in sera nor in secretions. The detection of antitrichomonal antibodies in controls, with no demonstrable trichomonal infection, may be accounted for previous infection.

Length and hatchability of Schistosoma mansoni eggs.

Mature Schistosoma mansoni eggs, purely isolated from the intestines of infected mice, were allowed to hatch and classified microscopically according to their lengths. The hatching percentage and the type of shell rupture were studied. An inverse relationship between the length and hatchability of eggs was proved. Smaller eggs have a high hatchability percentage, while eggs larger than 160 um in length failed to hatch. The predominance of oblique type of tear in the shells after rupture suggests a longitudinal arrangement of egg shell chemical constituents.

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.

Electron microscope and histochemical studies on the oncosphere of Hymenolepis nana.

The ultra and histochemical structures of the oncosphere of Hymenolepis nana were studied. The oncosphere is surrounded by several protective layers. The outer envelope appears to be cellular in origin and consist of an electron dense outer zone and an inner granular zone, mucoprotein in nature. The inner envelope and embryophore are a continuous morphological unit of a protein structure. Within the oncosphere, apart from hooks, there are two germ cells, two somatic cells and a large penetration gland. The oncospheral hooks consist of three layers and elicit a positive reaction for keratin. The penetration glands fill the posterior region of the embryo and contain granules of varying density and shape.

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.

Histocompatibility (HLA) antigens in Egyptians with two parasitic skin diseases (scabies and leishmaniasis).

The frequency of human leucocytic antigens (HLA) were studied in 62 patients with scabies and 27 patients with cutaneous leishmaniasis to evaluate the role of HLA antigens as genetic markers in the pathogenesis of these parasitic skin diseases. A significant statistical association was proved between HLA-A11 antigen and scabies and between HLA-A11, -B5 and -B7 antigens and diffuse cutaneous leishmaniasis.

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.

The course of Giardia muris infection in immunocompetent and immunocompromised mice.

No significant sex-related difference was observed in immunocompetent mice. Sexually mature mice of both sexes excreted large numbers of Giardia cysts over a longer period than did immature ones. Cyclosporin A has compromised the immunological response of the primary Giardia infection. However, it does not affect the ability of the immune host to resist challenge infection. The use of this drug may cause fulmination of giardiasis.

Seasonal variation and incidence of Stictodora tridactyla in fish from lake Manzala.

Stictodora tridactyla encysted metacercariae were detected in Mugil and Tilapia collected only from brackish water fish from lake Manzala. The prevalence and intensity of encysted metacercariae were higher in summer than in winter.

An electron microscope study on spermatogenesis in Hymenolepis nana.

Only on the basis of nuclear size, spermatogonia can be easily identified by their relatively large prominent nuclei. Further meiotic division occur resulting in primary spermatocytes. The nuclei become smaller, placed peripherally forming the spermatids. A membrane-bound clefts develop in the cytoplasm in the region of spermatid nuclei and that such clefts eventually enclose the elongated nuclei to become the plasma membrane of the sperm. There is a common general pattern of spermatogenesis in cestodes which follows the pattern typical of the platyhelminthes.

Ultra structural studies of the surface of Hymenolepis nana by scanning and transmission electron microscopy.

Scanning electron microscopy of the surface of Hymenolepis nana indicated that dense populations of microtriches occur on scolex proper, suckers and strobila, with an average density of 20/micron2. The excellent preservation of microtriches proves the efficacy of the critical point drying method for preparing cestodes for study of SEM. The cytological structure of the tegument of H. nana corresponds in general to that of other tapeworms.

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.