Demographic, socioeconomic and environmental changes affecting circulation of neglected tropical diseases in Egypt

Egypt has been plagued by many neglected tropical diseases since Pharaonic time. These diseases are Schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis, leishmaniasis and fascioliasis beside the epidermal parasitic skin diseases. Indeed, theses diseases still persist as public health problem in the country by the influence of demographic, socioeconomic and environmental obstacles. This study seeks for understanding the contribution of each factor in each obstacle in neglected tropical diseases perpetuation which in turn could help the governorate in planning integrated control strategies. It was found that poverty, unregulated urbanization and inadequate sanitation are important socioeconomic factors that have great effect on the transmission dynamics of the diseases. The environmental factors which affect the epidemiology of these diseases in the country are scarcity of water, construction of dams, land reclamation for agriculture beside the climate factors. Unfortunately, the panic increase in the population growth rate minimizes the efforts done by the governorate to elevate the public health services. These conditions also affect the transmission of epidermal parasitic skin diseases including scabies, head lice and hookworm-related cutaneous larva migrans. The control programs and the recommendations to combat the diseases were discussed. The present study showed that the ecological factors affecting each neglected tropical disease in Egypt are somewhat similar which makes it worthy to develop an integrated control approaches aiming at improving the leading factors of neglected tropical diseases circulation in the country.

Demographic, socioeconomic and environmental changes affecting circulation of neglected tropical diseases in Egypt

Egypt has been plagued by many neglected tropical diseases since Pharaonic time. These diseases are Schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis, leishmaniasis and fascioliasis beside the epidermal parasitic skin diseases. Indeed, theses diseases still persist as public health problem in the country by the influence of demographic, socioeconomic and environmental obstacles. This study seeks for understanding the contribution of each factor in each obstacle in neglected tropical diseases perpetuation which in turn could help the governorate in planning integrated control strategies. It was found that poverty, unregulated urbanization and inadequate sanitation are important socioeconomic factors that have great effect on the transmission dynamics of the diseases. The environmental factors which affect the epidemiology of these diseases in the country are scarcity of water, construction of dams, land reclamation for agriculture beside the climate factors. Unfortunately, the panic increase in the population growth rate minimizes the efforts done by the governorate to elevate the public health services. These conditions also affect the transmission of epidermal parasitic skin diseases including scabies, head lice and hookworm-related cutaneous larva migrans. The control programs and the recommendations to combat the diseases were discussed. The present study showed that the ecological factors affecting each neglected tropical disease in Egypt are somewhat similar which makes it worthy to develop an integrated control approaches aiming at improving the leading factors of neglected tropical diseases circulation in the country.

utility of direct agglutination [DAT] and fast agglutination screening [FAST] tests in serodiagnosis of experimental microsporidiosis

The present study was designed to evaluate the efficiency of two serodiagnostic tests; the direct agglutination test [DAT] and the fast agglutination screening test [FAST] in the diagnosis of Microsporidia in experimentally infected mice and to differentiate between different species of the parasite. The swiss albino mice were divided into non infected control and infected experimental groups which were further subdivided into ten subgroups. Ten samples of microsporidial spores were isolated from ten human stools and each one was used to infect each subgroup of mice. Stool and sera were collected weekly from each subgroup from the 1[st] to the 4[th] week post infection [PI]. DAT and FAST tests, using antigen prepared from the different species of microsporidial spores were used to detect antibodies in sera of different mice subgroups. The cross reactivity of microsporidial spores with the antibodies of Cyclospora cyatenensis and Cryptosporidium parvum was investigated by DAT and FAST. The results proved that DAT and FAST were effective in detecting microsporidial antibodies in sera of experimentally infected mice from the 2[nd] week PI till the end of the study, without cross reactivity with C. cyatenensis or C. parvum. They failed to differentiate between different Microspoiridia species used but, they gave good interpretation and they were specific and sensitive, and did not need sophisticated equipments

use of ELISA and immunohistochemistry techniques for detection of toxoplasma gondii antigen in tissues of experimentally infected mice

The capability of double antibody sandwich enzyme-linkad immunosorbent assay [ELISA] for detecting antigens of Toxoplasma gondii [T. gondii] in different mice tissue specimens was evaluated in comparison to the immunohistochemistry [IHC] technique. Results proved that tissue antigens were detectable in liver, kidney and mesenteric lymph node [LN] specimens by both methods from the second day of infection, with statistically significant increase in its amount in all organs throughout the period of the study. Using ELISA technique, the highest antigen level was recorded on the second day [0.120 +/- 0.0015] and the fourth day [0.147 +/- 0.0034] of infection in LN specimens, while, the liver showed the highest antigen level at the sixth day post infection [PI][0.165 +/- 0.0066]. On the other hand, using the IHC technique, the highest number of tachyzoites was recorded in LN sections in all studied durations, the second, the fourth and the sixth days PI [1.1 +/- 0.875, 1.6 +/- 1.173 and 3.1 +/- 1.370 respectively]. Thus, sandwich ELISA technique might offer a valuable aid for rapid diagnosis of acute toxoplasmosis in human tissues, and it has proved to be more accurate than IHC technique, since its results was coincided with the pathogenesis of the disease.

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 times. The results revealed that boiling of protozoa for one minute minimized their viability to less than 1% and rendered them noninfectious, while the exposure to 4C and -4C up to seven days preserved their viability and infectivity. Whereas, it was found that salinity was effective at a high concentration [50 ppt] for a long storage time at lower concentrations

Effect of ozone on the viability of some protozoa in drinking water

In this study, water samples from household tanks in several districts of Alexandria were examined for protozoa contamination and studying the effect of ozone and chlorine on their viability. The parasitic protozoa encountered were Giardia, Cryptosporidia, Blastocystis, Cyclospora and Microsporidia. Distilled water was treated by ozone or chlorine. Ozonated water samples were prepared at a concentration of 1 ppm after contact times with ozone of three, five, seven and nine minutes. Chlorine concentrations were 4 and 8 ppm. Parasites were incubated overnight at room temperature with the treated distilled water. The viability of the parasites was assessed by examining the intestinal sections of the infected animals

Morphology, histochemistry and infectivity of blastocystis hominis cyst

Different morphological forms of Blastocystis hominis were identified in human stool samples including both cystic and trophic stages. The latter was induced to encyst by keeping them in potassium dichromate solution for two weeks. Suspected of being the infective stage, cysts were studied in more detail as regards their morphology using both light and electron microscopy. Histochemistry and infectivity studies were also carried out

In-pouch TV culture system in diagnosis of trichomonas vaginalis infection

A newly simplified culture method, the In-Pouch TV culture system, the wet mount [WM] examination and the acridine orange stain were compared with the Oxoid culture as a standard technique in the diagnosis of trichomoniasis. Out of 70 symptomatic cases enrolled in this study, 28 specimens were positive by all methods. Among these positive specimens, 21 were positive by the Oxoid culture [75%] and 24 [85.7%] with sensitivity of 85.7% by the In-Pouch system. Both wet mount preparation and acridine orange stain had less sensitivity than the In-Pouch system [61.9%] and detected 15[53.6%] and 16 [57.1%] of the cases respectively. The In-Pouch system has been proved to be easier in the transport and culture technique than the ordinary culture method. It alleviates the need to enter the culture, thus prevents contamination. Its cost is comparable to the ordinary culture tube. Therefore, it is recommended to use the In-Pouch culture system as a method of diagnosing trichomoniasis

Studies on a newly emerging protozoal pathogen: cyclospora cayetanensis

Cyclospora is frequently misdiagnosed with Cryptosporidia. Stool samples were collected from 150 immunocompromised patients and concentrated by the parasep fecal parasite concentration and the discontinuous Percoll gradients methods. Wet mount examination was done and the parasite was successfully stained with modified Ziehl Neelsen [ZN] and safranin methylene blue stain. Cyclospora was detected in 4% of the examined cases. Cyclospora was easily differentiated from Cryptosporidia by using the modified detergent ZN stain, whereby Cyclospora resisted staining and Cryptosporidia pick up the pink coloration. Scanning and transmission electron microscopic examinations were done to the unsporulated Cyclospora oocysts. They appeared as spherical objects with an outer fibrillar coat, an indentation and sutures. These spherical objects also contained light and dark granules. In studying the possible sources of transmission of this parasite, sporulated and unsporulated oocysts were detected in tap water and lettuce heads, which supported the theory that water and food could be the sources of transmission of this parasite

Embryonic stages of toxocara canis in eggs

Observation of Toxocara canis fertile eggs removed from the vagina uterina of female worms showed that they are ovoid to spheroid and have a shell formed of four layers, the outermost is pitted. Infertile eggs were less uniform in shape and did not have well developed shell layers. To study the developmental stages and in trying to determine the infective stage, cultivation of eggs in 1% formalin was done. It was found that the first stage larva appeared at the eighth day of cultivation, and the first moult on the twelfth day followed by the second moult over days 14-16 as proved by finding of transient loose double-layered sheath over the definitive cuticle. This proved that the infective stage is the third stage larva inside the egg. Infectivity to mice appeared on day 18, reached the maximum at 32 days and gradually declined thereafter. The infective larva did not develop or form a sheath during in vitro culture

Ultrastructure study of toxocara canis infective larvae extracted from eggs

The ultrastructure of Toxocara canis infective larvae is described. The buccal opening, the vestibule and esophagus are lined by a thick cuticle. Between the buccal opening and the vestibule, there are cuticular projections which might function as a valve. Epithelial cells that are associated with the vestibule and surround the esophagus, showed cytoplasmic lamellae with the possible osmoregulatory function of these cells. Active secretory gland cells are present in the esophagus. The secretion produced by these cells might be used to facilitate the migration of the larva. The unicellular excretory apparatus is typical of the ascarid group. Two lateral excretory columns extend on either side of the intestine, the excretory canaliculi are not well differentiated. The intestine is seen without apparent lumen and contains fat globules and glycogen particles which are found to be reduced in number in old larvae