Host feeding of mosquitoes (Diptera: Culicidae) associated with the recurrence of Rift Valley fever in Egypt

In 1993, Rift Valley fever (RVF) virus reappeared in Egypt. We determined the prevalence and feeding patterns of mosquitoes in 5 villages where the virus was active. Of 10 species recovered, Aedes caspius (Pallas), Culex pipiens L., Cx. antennatus (Becker), and Cx. perexiguus Theobald constituted 99% of > 35,000 mosquitoes captured in dry ice-baited CDC light traps. Ae. caspius was most prevalent, except at Nag' El Hagar where it was replaced by Cx. perexiguus. Cx. pipiens ranked 2nd, except at Nag' El Ghuneimiya, where it was replaced by Cx. antennatus. Most blood meals analyzed by an enzyme-linked immunosorbent assay reacted to > or = 1 antiserum. Cx. pipiens was mainly anthropophagic, and therefore may have been the main vector of RVF virus among humans. Ae. caspius feeds were chiefly from humans, bovines, and equines. Cx. antennatus and Cx. perexiguus fed generally on bovines. Mixed blood meals from humans and RVF virus susceptible animals were identified in the predominant mosquitoes. Prevalence and host selection, as well as predicted probability for a blood meal being interrupted, indicated that Ae. caspius may have served as a bridge vector between humans and bovines in 4 of the villages. Cx. perexiguus may have played this role at Nag' El Hagar. Because potential vectors are abundant, susceptible domestic animals are associated closely with humans, and surveillance of imported livestock is not systematic, we conclude that RVF virus sporadically will recur in Egypt.

Relationship between circulating antigen level and morbidity in Schistosoma mansoni-infected children evaluated by ultrasonography

Ninety-eight Schistosoma mansoni-infected children from an endemic area in Sharkia Governorate, Egypt were evaluated by abdominal ultrasonography to determine liver and spleen sizes, grade of periportal fibrosis, and splenic vein diameter. Circulating antigen levels were measured using a double sandwich ELISA in which the sensitivity was 91.8% and specificity was > 99%, with no evidence of cross-reactivity with other parasites. No significant relationship was observed between antigen level and clinical stages of the disease as assessed by physical examination (P > 0.05). When ultrasound was used to stage disease, the mean antigen level was significantly higher among hepatosplenic cases than intestinal cases (P < 0.05). No difference in mean antigen levels were found between the splenic and hepatic cases. Furthermore, a direct correlation (P < 0.01) was observed between antigen level and disease severity as monitored by ultrasonography. Antigen level showed a positive correlation with the degree of periportal fibrosis (P < 0.05). Moreover, a significant increase in the percent of children who were antigen positive (> 80 ng/ml) was found in those with more severe periportal fibrosis (P < 0.001). The findings suggest that ultrasonography along with measurement of circulating antigen levels predict morbidity in schistosomiasis mansoni.

Idiotypic regulation in Schistosomiasis mansoni

The role of anti-idiotype Ab2 in regulation of the immune response in schistosomiasis was studied. Positive Ab2 could be detected among the newborns of infected mothers and experimentally S. mansoni- infected mice. Negative anti-idiotypic antibodies were observed among children above 3 years and control mice. Increasing levels of anti-idiotypic antibodies were detected among S. mansoni infected children and adults. Higher mean anti-idiotype A2 levels were found among patients with hepatosplenomegaly than those with intestinal manifestations. The kinetics of anti-idiotype Ab2 among the S. mansoni- infected mice started from the end of the first week after infection up to 8 weeks. It was continuous, but with undulating levels. Moreover, the anti-idiotype antibody was able to stimulate lymphocyte proliferation at 8 weeks post infection.

Differences in spatial visualization as a function of scores on hemisphericity of mathematics teachers

59 teachers of mathematics were administered the Your Style of Learning and Thinking-Form A and categorized as showing Left (n = 13), Right (n = 12), or Integrated (n = 15) hemisphericity. Rotations scores on the Purdue Spatial Visualization Test were not statistically significant among the three groups.

Colchicine therapy for hepatic murine schistosomal fibrosis: image analysis and serological study

Colchicine in a dose of 200 micrograms kg body weight/day (5 days/week) was administered to groups of Schistosoma mansoni infected mice 12 weeks post infection, either alone or following previous praziquantel therapy at the 8th week of infection. Certain groups received colchicine for 6 weeks and others received it for 10 weeks. Colchicine alone did not significantly change the light microscopic appearance of schistosomal liver fibrosis, or hepatic collagen content estimated histomorphometrically, and did not reduce the elevated IL-2 serum level. Colchicine induced hepatic injury consisted of intense inflammatory reaction in granuloma and portal tracts, hepatocytic degeneration, and elevation of serum AST and ALT levels. Colchicine seemed to postpone granulomatous reaction healing and collagen deposition rather than inhibiting collagen formation or degrading it. Colchicine inhibited proliferation of hepatocytes of infected mice by expanding G2-M phases of cell cycle, thus reduced Ag NOR count and raised cell ploidy and cyclic AMP serum level. Subsidence of schistosomal infection by praziquantel prior to colchicine therapy greatly reduced inflammatory cellular reaction, significantly diminished hepatic collagen deposition and serum IL-2 level, minimized the elevated nuclear ploidy and cyclic AMP serum level that followed colchicine therapy when administered alone.

Environmental determinants of the distribution of Phlebotomus orientalis in Sudan

Despite its importance as a vector of visceral leishmaniasis in Sudan, the ecology of Phlebotomus orientalis is still poorly understood. The results of a ground-based survey and a geographical-information-system (GIS) study, carried out to investigate the environmental determinants of the distribution of P. orientalis in the wooded areas of the central savannah belt of Sudan, are described here. The survey, carried out in April-June 1996, consisted of a collection of sandflies over two consecutive nights at each of 44 study sites, using three CDC, miniature, light traps at each site. During the survey, the ecology of each site was described. Phlebotomus orientalis was caught at 17 of the sites. Environmental data on the collection sites (rainfall, minimum and maximum temperatures, soil class, vegetation and land-surface-temperature indices) were extracted from a range of sources of digital data collected by satellites in the National Ocean and Atmospheric Administration's series. These data were then analysed, to ascertain which variables were significantly associated with sites positive for P. orientalis. In line with the results of previous studies, P. orientalis was found to have a significant association with the presence of the tree species Acacia seyal and Balanites aegyptiaca and with the black cotton (vertisolic) soils of eastern Sudan. The positive sites were found to have significantly higher annual mean maximum and minimum daily temperatures than the negative sites and the annual mean maximum normalized-difference vegetation index (NDVI) value was also found to be significantly higher in these sites than in sites where no P. orientalis were found.

Detection of circulating antigens in patients with active Schistosoma haematobium infection

An antigen-capture ELISA using monoclonal antibody (MAb) 128C3/3/21 was used to detect circulating parasite-derived antigens in the sera of patients actively infected with Schistosoma haematobium (31 males and four females, 5-25 years of age). The assay had a sensitivity of 100% (35 of 35 patients with antigen levels > 80 ng/ml) and a specificity > 99%. We used this ELISA to monitor antigenemia before treatment and one, three, and six months after treatment with a single oral dose of praziquantel (PZQ) (60 mg/kg in 20 patients or 40 mg/kg in 15 patients) and compared our findings with those indicated by other measures of disease progression. Circulating antigen levels decreased drastically after PZQ treatment (P < 0.001), with a significantly higher decrease occurring after treatment with 60 mg/kg than with 40 mg/kg. Although the mean antigen level was still significantly reduced (P < 0.001) at six months after treatment, 16 patients remained antigen-positive after six months, and nine had increased levels of antigenemia, reflecting reinfection in six patients and persistence of infection in another. We observed a correlation (r = 0.6, P < 0.01) between the level of circulating antigen and the intensity of infection as measured by egg count. We also found a direct relationship (P < 0.001) between antigen level and the severity of the disease as monitored by ultrasonography. We conclude that our ELISA may be a useful adjunct to other methods, such as ultrasonography, for monitoring the course of S. haematobium infection and treatment.

Role of ELISA in early detection of Fasciola copro-antigens in experimentally infected animals

An immunodiagnostic sandwich enzyme-linked immunosorbent assay (ELISA) was performed for the detection of F. hepatica antigens in stool sample (copro-antigens) of experimentally infected animals (mice, rats and rabbits) over a period of 18 weeks using affinity-purified polyclonal antibodies raised against the whole adult F. gigantica. The test demonstrated fascioliasis in mice earlier than in rats or rabbits (4, 6 and 7 weeks post infection respectively) by detection of copro-antigens in stool samples. In all experimentally infected models, F. hepatica copro-antigens concentration showed continuous increase and mice samples had higher antigen concentration than rats and rabbits. Sensitivity of ELISA was significantly higher in mice (83.3%) than in rats and rabbits (75% and 66.7% respectively) and its specificity showed nearly similar results to sensitivity. From the previously obtained data, it could be concluded that ELISA proved to be a rapid, easy and sensitive test for diagnosing fascioliasis by detection of F. hepatica copro-antigens earlier than routine stool examination of Fasciola eggs.

Effect of octreotide on the pathology of hepatic schistosomiasis

In clinical practice, octreotide (CAS 83150-76-9) has its greatest impact in the management of bleeding varices. The present work is the first one which was undertaken to investigate the possible use of octreotide as an antifibrotic agent and to study its effect on hepatic vasculature in Schistosoma mansoni infection. The material of this investigation consisted of two groups of albino mice (A, B), subdivided each into normal control, infected control, subgroups treated with octreotide, praziquantel (CAS 55268-74-1), and a combination of octreotide and praziquantel. Groups A and B were sacrificed at the 8th week and the 18th week post infection, respectively. By analysis of the obtained results, octreotide induced a reduction of the portal pressure, the weight of the spleen and the liver, the liver egg load (number of eggs) granuloma size and cellularity, and of the degree of hepatic fibrosis quantified by serum N-terminal peptide of type III procollagen in serum, serum laminin and tissue collagen using a Picrosirius red dye assay. Moreover, the biochemical state of hepatocytes has been improved. The subgroups treated with octreotide in association with praziquantel revealed better results than the subgroups treated with praziquantel alone. These obtained data were analysed in terms of histological extent of liver fibrosis in sections stained with Masson trichrome and sirius red, hepatocytic and sinusoidal changes at an ultrastructural level and by immunohistochemical demarcation of endothelial cells of blood vessels through the determination of factor VIII-related antigen. The promising results detected in this study may encourage to further investigate the positive findings of this drug with the intention of its possible application on a clinical level.

Simple assay for detection of circulating antigens in children infected with schistosomiasis

The ability of monoclonal based dot-ELISA and a previously described solid-phase ELISA were directly compared to detect circulating schistosomal antigens in sera from 50 Egyptian individuals with parasitologically proven schistosomiasis. The mAb employed, 128C3/3/21, recognized a repeating carbohydrate epitope expressed at all stages of the parasite development. The same mAb and patient serum samples were used i both tests, 17 samples from age-matched individuals infected with other parasites but not with Schistosoma were also tested. In the dot-ELISA, 44 serum samples (88%) were found to contain parasite antigens when screen at a dilution of 1;24, 43 serum samples (86%) were positive in the solid-phase ELISA at 1:8 dilution and only 37 (74%) samples were positive at 1:24 dilution. The specificity of the dot-ELISA was 93% as compared to > 99% for the solid-phase ELISA. The detection limit of dot-ELISA was 0.01 ng/ml, whereas only > 1 ng/ml could be detected by the solid-phase ELISA. As dot-ELISA does not require radioactivity or sophisticated equipment, so it is practically well suited for use in endemic areas in developing countries.

Octreotide decreases connective tissue formation and improves vascular changes associated with hepatic schistosomiasis

In clinical practice, Octreotide has its greatest impact in the management of bleeding varices. The present work is the first one which was undertaken to investigate the possible use of Octreotide as an antifibrotic agent and to study its effect on hepatic vasculature in Schistosoma mansoni infection. The material of this investigation consisted of two groups of albino mice (A&B) subdivided each, into normal control, infected control, Octreotide treated, Praziquantel treated and Octreotide with Praziquantel treated subgroups. Groups A & B were sacrificed at the 8th week and the 18th week post infection respectively. By analysis of the obtained results, Octreotide has induced reduction of the portal pressure, the weight of the spleen and the liver, the number of liver egg load, granuloma size and cellularity, and of the degree of hepatic fibrosis quantified by serum PIIINP, serum laminin and tissue collagen using sirius red dye assay. Moreover, the biochemical state of hepatocytes has been improved. The subgroups treated with Octreotide in association with Praziquantel revealed better results than the subgroups treated with Praziquantel alone. Data were analysed in terms of histological extent of liver fibrosis in sections stained with Masson trichrome and sirius red, hepatocytic and sinusoidal changes at an ultrastuctural level and by immunohistochemical demarcation of endothelial cells of blood vessels through the determination of factor VIII related antigen. The promising results detected in this study may encourage to further investigate the positive findings of this drug with the intention of its possible application on a clinical level.

Determination of the population pharmacokinetic parameters of sustained-release and enteric-coated oral formulations, and the suppository formulation of diclofenac sodium by simultaneous data fitting using NONMEM

Data from sustained-release and enteric-coated oral formulations, and the suppository formulation of diclofenac sodium are fitted simultaneously using NONMEM and the general linear model, ADVAN 5. Absorption and disposition parameters, serum levels, and absorption profiles were determined. The in vivo absorption profiles were determined using the program TOPFIT. The in vivo absorption for the sustained-release formulation is slow first order and follows a flip-flop model since disposition rate constants are greater than absorption rate constants. Absorption from the enteric-coated form is essentially complete (> or = 95%) at about 7.5 h, while it is 95% complete at 24 h from the sustained-release formulation. This suggests likely absorption from the colon in the case of the sustained-release formulation since absorption is only 75% complete during the first 10 h. The sustained-release relative bioavailability is 90-99%. Absorption from the suppository is essentially complete at about 4.5 h. However, the relative bioavailability of the suppository formulation is low (55%), since defecation may remove the drug from the absorption site before complete absorption.

Transmission of circulating schistosomal antigens from infected mothers to their newborns

Two previous reports have appeared in the literature regarding tansplacental transfer of Schistosoma mansoni antigens which raised the question of its reality. In a previous study the senior author, and others (1992 & 1997) detected circulating antigens of S. mansoni and S. haematobium in infected patients, using monoclonal antibodies 128C3, with a very high sensitivity using ELISA. This work tried to answer the question of antigen transfer possibility using a high sensitive assay in 50 mothers and their newborns at birth and 1, 3, and 6 months after delivery. The assay used in the present work could detect circulating S. mansoni antigens in 45 infected mothers (90%) with active S. mansoni infection. A significant direct increase in mean antigen levels was found with the intensity of infection evaluated by egg counting (p < 0.01). The clinical stage of the diseased mothers was apparently unrelated to the ELISA test values as no significant relations were observed. Positive antigen levels were detected in 33 newborns (66%) of the 45 positive antigen mothers, then the percentage positivity was directly decreased with the advancement of age as only 5 infants (10%) had positive antigen levels compared to 0% at 6 months of age. A positive correlation between newborn serum antigen concentration and concentration of antigen in sera of their mothers was obtained. This work answers some of the questions concerning the ability of the used monoclonal to detect antigens in newborns and the possibility of antigen transfer through the placenta alone or incorporated in immune complexes forms. This work clarifies the time of antigen disappearance from the circulation.

The importance of detecting circulating Toxoplasma antigens in human cases

This work was performed on 100 suspected toxoplasmosis cases including 75 females with complicated obstetric histories, 15 children presented with hydrocephalus, retino-chorditis and lymphadenitis and 10 children suffering from leukaemia. Also 40 age-matched controls were included in this study. Serum samples from all patients and controls were examined to detect anti-Toxoplasma IgG and IgM using indirect ELISA. Antiserum against Toxoplasma avirulent strain was prepared in New-Zealand white rabbit, then it was used after purification for detecting circulating Toxoplasma antigens in the sera of these studied groups using a double antibody sanwich ELISA technique. Positive anti-Toxoplasms IgG was detected in 45% of the female group while 19% were IgM positive. According to IgM/IgG ratio, 9 cases were considered as acutely infected-females and 25 as chronically infected ones. The mean optical density of both IgG and IgM among acutely and chronically infected females were found significantly higher than of the control groups. Ten non-leukaemic children were IgG and IgM positive cases and were considered as acutely infected patients. On the other hand, all children with leukaemia were negative for anti-Toxoplasma IgG and IgM. Eleven out of 19 acutely infected cases (58%) had positive Toxoplasma antigens, whereas, only one case (4%) with chronic infection had positive antigen level. The mean optical density of circulating antigen level was significantly higher among acutely infected females and children than chronically infected and control groups. No antigen level difference was found between chronically infected patients and control groups. Six children from leukaemic group (60%) had positive circulating Toxoplasma antigen levels with significantly higher mean optical density than control groups (P < 0.001). As a conclusion the results demonstrate that the detection of circulating antigens can aid in the diagnosis of infection by T. gondii in humans, specially in immuno-compromised patients whose serologic response can be impaired.

Evaluating the detection of circulating filarial antigen in diagnosis of bancroftian filariasis and filarial hydrocele

Four groups of patients were selected: 16 patients with clinical evidence of obstructive filarial lymphangiopathy without microfilaraemia; 12 patients with clinical evidence of obstructive filarial lymphangiopathy with microfilaraemia and 9 patients with microfilaraemia. Two control groups were also included. Blood films, sera and hydrocele fluid samples were collected from all subjects. Polyclonal antibody against Dirofilaria immitis worm homogenate was prepared, fractionated and conjugated with HRP. Both polyclonal antibody and monoclonal antibody (AD12) were used in a sandwich ELISA. Using polyclonal antibody, both microfilaraemic groups (groups 2 and 3) had a significantly higher mean O.D. readings than that of control groups (P < 0.05), whereas, the mean O.D. readings of patients with symptomatic amicrofilaraemia had no significant difference than control groups. Symptomatic microfilaraemic group had the highest percentage of antigen positivity 7/12 (58.3%) among all groups while symptomatic amicrofilaraemic group had the least antigen positivity 2/16 (12.5%). Patients presented with elephantiasis only or with hydrocele had no antigen positive levels 0/12 (0%) in their serum or hydrocele fluid samples. On the other hand, 2 out of 4 cases represented with hydrocele (50%) had positive antigen levels in their hydrocele fluid samples. Using monoclonal antibody, all groups had a highly significant higher mean optical density readings than control groups. Asymptomatic microfilaraemic group had the highest percentage of antigen positivity 8/9 (88.9%), followed by symptomatic microfilaraemic 8/12 (66.7%), then symptomatic amicrofilaraemic group 4/16 (25%). The same 2 patients (amicrofilaraemia) and 7 (microfilaraemia) represented with hydrocele had positive antigen levels in their hydrocele fluid samples.

A survey of larval and adult mosquitoes on the flood plains of Bangladesh, in relation to flood-control activities

A mosquito survey was carried out between October 1991 and November 1992 on the flood plains of Bangladesh, as part of a baseline study designed to help predict the effects on vector-borne diseases of embanking rivers under the Bangladesh Government's Flood Action Plan. Overall, 15 species of larval and 15 species of adult anophelines were collected, along with 13 larval and 21 adult culicines. Anophelines made up only 6% of the mosquitoes caught at human bait. The most abundant anopheline biting man was Anopheles vagus, the dominant species in all nine sampling villages. The other recognized malaria vectors in the flood plains of Bangladesh, namely An. philippinensis, An. aconitus and An. annularis, were collected but in relatively low numbers. Culex vishnui was the most abundant biting culicine in all villages. Biting mosquitoes showed a bimodal seasonality of biting, with peaks between February and April and September and October. All biting mosquitoes showed a significant preference for outdoor biting. The densities of the mosquito populations are more likely to be affected by the large-scale environmental changes which have occurred in Bangladesh, as well as the dramatic increase in the density of the human population, than by the river embankments per se.

The reference value of erythrocyte sedimentation rate for differential diagnosis of rheumatic fever among Bangladeshi children

The aim of the present study is to determine the reference value of erythrocyte sedimentation rate for differential diagnosis of rheumatic fever in the National Center for Control of Rheumatic Fever and Heart Diseases, Dhaka, Bangladesh among patients with signs and symptoms which may be related to acute rheumatic fever. All medical records for the patients aged 5 to 20 years who attended the outpatient department of the hospital between July, 1994 and November, 1995 were reviewed. Fifty-three of 337 such patients had acute rheumatic fever defined by the updated Jones criteria. The performance of erythrocyte sedimentation rate test was evaluated by sensitivity, specificity, positive predictive value, and receiver operating characteristic curve. The findings of this study suggest that the lower limit for a positive test should be considered at 30 mm (Westergren 1 h) in this hospital.

Evaluation of colchicine with or without praziquantel therapy in the control of hepatic fibrosis in murine schistosomiasis

Colchicine alone or following praziquantel was given to mice infected with Schistosoma mansoni either 6 or 10 weeks post infection. Praziquantel increased body weight gain, histologically reduced number, diameter and cellularity of granuloma and improved liver function parameters. Early praziquantel therapy decreased hepatic collagen content as detected by the colorimetric method and the serum procollagen propeptide (PIIIP), while later treatment at the 10th week of infection increased hepatic collagen content and serum PIIIP. Colchicine therapy significantly decreased body weight gain with significant weight loss after early treatment. Colchicine did not change the histologic picture of schistosomal liver fibrosis; it induced a detectable hepatocytic injury recorded ultrastructurally and histologically with excitation of the inflammatory reaction in the granuloma and in portal tracts after early treatment. Excess pigmentation in macrophages and Kupffer cells, binucleation and large sized hepatocytic nuclei were evident after colchicine therapy. Colchicine increased hepatic collagen content microgram/mg protein, raised globulin and total serum protein and normalized the raised serum PIIIP of infected mice, but had no effect on PIIIP of normal mice. Early cessation of schistosomal infection evidently minimized the adverse effects of colchicine.

Parasitic causes of hepatomegaly in children

Three hundred children with hepatomegaly were selected. They were subjected to full clinical and laboratory examinations. Also serum samples were examined to detect IgG using ELISA against SEA, chromatography purified hydatid cyst antigen, commercially available Toxoplasma antigen, partially purified adult Fasciola antigen and second-stage larvae Toxocara canis antigen. IFAT was used to detect IgG against Toxoplasma and T. canis. A commercially available IHAT kit for leishmaniasis was used. Based on immunological assays, 125 cases were suffering from various parasitic infections. Thirty cases with schistosomiasis (10%), 26 cases fascioliasis (8.7%), 18 toxocariasis (6%), 35 toxoplasmosis (11.7%), 3 cases hydatidosis (1%) and 13 cases mixed parasitic infections. No parasitic causes could be found in 175 cases (58.3%). Moderate or marked hepatomegaly favours the presence of schistosomiasis. Whereas, most cases with other parasites and those with non-parasitic infections fall in the category of mild hepatic enlargement. There was no associated splenomegaly in cases with Fasciola, Toxocara, hydatid disease and/or the non-parasitic group. Most of hepatomegalic cases with non-parasitic causes were found to be associated with fever (88.5%). Fever was found in nearly 50% of cases with either Toxoplasma or Toxocara infections. Mild eosinophilia was found in all cases with parasitic causes. Only 24 cases of non-parasitic group (13.7%) had easinophilia. Moderate and high eosinophilia were found in cases with fascioliasis and toxocariasis. Cases with fascioliasis had a statistically significant increase in enzymes activities specially alkaline phosphatase. It was concluded that parasitic infections should be considered as an important cause of liver enlargement in children. Serological methods using purified antigenic fractions are an important tool for diagnosis.

Detection of Pneumocystic carinii in immuno-suppressed rats by different histological stains and immunological assays

Detection of P. carinii in lung sections of 35 immuno-suppressed albino rats was evaluated using five histological stains (toluidine blue "O", Giemsa, Gram's stain, PAS and H & E) and two immunological assays (indirect immunofluorescence [IIF],, and indirect immunoperoxidase [IIP]) using polyclonal antibody, raised in white New Zealand rabbits, against rat P. carinii. In spite of the high sensitivity of the histological stains, they yield hazy details insufficient for easy identification with difficult interpretation. However, Gram and PAS stains provided a better visualization with easy identification of the parasite. On the other hand, both immunological assays allowed an accurate rapid interpretation of the stained slides. The IIP technique, having 100% sensitivity in detecting the precipitated parasite antigens with absolute specificity, seems to be a good diagnostic tool for detecting P. carinii in lung sections.

Surface roughness of dentin after tooth preparation with different rotary instrumentation

Although surface finish can be a critical variable in clinical performance, there is a dearth of information regarding surface characteristics of teeth prepared for artificial crowns. This study characterized teeth prepared for complete cast restorations using three representative types of rotary instruments. One hundred and five standardized tooth preparations for complete crowns were performed using a modified milling machine on extracted human teeth with diamond, tungsten carbide, and tungsten carbide finishing burs of similar shape (n = 35). The prepared dentin was analyzed with a surface profilometer and a scanning electron microscope (SEM). Differences between rotary instrument groups were determined with parametric ANOVA and Tukey's Studentized Range (HSD). Statistically significant differences in the surface topography of prepared teeth were open. Mean surface roughnesses (Ra) were 8.6 and 6.8 mum for teeth prepared with diamond and tungsten carbide burs. Teeth completed with finishing burs appeared to result in a smoother surface (1.2 mum).

Detection of Cryptosporidium antigen in stool samples among diarrhoeic children

A double antibody sandwich ELISA technique, using a chromatography purified Cryptosporidium antiserum (fractiuon 1), was applied to detect faecal antigen in children infected with Cryptosporidium suffering from diarrhoea. The assay could detect antigens in 55 out of 60 (91.7%) infected children. False positive reactions were detected in 4 children infected with E. histolytica and 2 children with Giardia. The mean level of copro-antigen was higher in children, below 10 years, than in older patients, with a highly significant difference. A significant higher mean copro-antigen level was found among children below 2 years of age who were bottle feeders when compared to those receiving breast feeding. Higher mean optical density readings was obtained in those with severe forms of diarrhoea than mild or moderate forms with statistically significant difference (P < 0.01). It was concluded that detection of Cryptosporidium antigens by ELISA technique in the stool samples is a highly sensitive (91.7%) and specific (85%) diagnostic method. It correlates well with the diarrhoea forms and the age of patients.

Prevalence of Fasciola infection among school children in Sharkia Governorate, Egypt

This study was performed on 1350 school children from 9 different villages in Sharkia Governorate to investigate the real situation of endemicity of fascioliasis in the area. Stool examination using modified Kato thick smear method was performed to detect Fasciola infection and other parasites. Those with negative stool samples were examined serologically by ELISA test to detect anti-Fasciola IgG. All cases with positive anti-Fasciola IgG were further examined by circum-oval precipitin test (COPT) against viable S. mansoni eggs to exclude the crossly reacted Schistosoma infections. Sixty nine cases were found to pass Fasciola eggs in their stool samples (5.1%). Anti-Fasciola IgG was detected in the sera of 231 children (17.1%) using ELISA test. Eighty four out of the 231 children were found positive by COPT and were considered as schistosomal cases. The remaining 147 who gave negative COPT were considered as Fasciola infections. All of the 69 Fasciola positive stool cases were found positive by ELISA test and negative by COPT test. The sensitivity of stool analysis was 47% versus 100% sensitivity of ELISA, whereas the specificity of ELISA was 63%. The total number of Fasciola positive cases by ELISA and stool analysis were 147 cases among 1350 children indicating a prevalence of 10.9% among school children in Sharkia Governorate. This results highlighting the importance of health education and snail control in decreasing the high prevalence.