Cryptosporidium and giardia in water in Alexandria: detection and evaluation of viability by flow cytometry and different stains

Cryptosporidium oocysts and Giardia cysts have become ubiquitous in surface waters worldwide. The number and extent of outbreaks of waterborne diseases indicate a significant risk for their possible transmission by drinking-water. Since many Egyptian cities depend on surface water as their main source of drinking water, knowledge of the prevalence of waterborne protozoa in water resources is important. The present study was designed to use flow cytometry to detect Cryptosporidium oocysts and Giardia cysts in water samples in Alexandria city in comparison with the standard staining techniques. Testing the viability of the encountered parasites was also carried out comparing flow cytometry and trypan blue vital stain. Thirty water samples were collected from water tanks from different districts of Alexandria city. Samples were subjected to staining techniques and flow cytometry. Stains used were modified Zeihl-Neelsen [MZN], safranin methylene blue [SMeB], modified trichrome, fluorescent stains [phenol auramine and acridine orange]. Viability was evaluated comparing trypan blue stain and flow cytometry using 4'-6-Diamidino-2-phenylindole immunostain [DAPI]. Flow cytometry proved to be much more sensitive than staining techniques with a sensitivity of 100% for both Cryptosporidium oocysts [30 samples] and Giardia cysts [11 samples]. Following flow cytometry, the fluorescent phenol auramine stain had the greatest sensitivity of 94.74% and 80% [18 and 4 samples, respectively]. The percent of live parasites present in each sample was always significantly higher by DAPI than trypan blue stain. The results of the present study clearly demonstrate that incorporation of flow cytometry can improve sensitivity of detection of Giardia cysts and Cryptosporidium oocysts in water samples. Although it is more expensive than the other staining methods, it is rapid, simple and accurate in estimating the quantity and viability of the parasites in each sample. Thus, flow cytometry can be recommended for detection of protozoa in water

Congenital trichinellosis in experimentally infected mice

The present study aimed at allocating the time during pregnancy at which transpiacental transmission of Trichinella spiralis [T. spiralis] larvae took place. Swiss albino mice were infected at different durations of pregnancy; five days before mating, on gestation day zero and five days after mating. Furthermore, to study the effect of immunosuppression on transplacental transmission, half of the experimental mice were immunosuppressed using cyclophosphamide drug [Endoxan]. The percentage of infected uteri, embryos and placentas and the mean larval count were calculated on day 8 post infection [PT]. Moreover, the percentage of infected offspring and the mean larval count in their muscles were estimated on day 30 P1. The results of the present study revealed that, transpiacental transmission of T. spiralis could occur in offspring of mice when their mothers are infected before or after pregnancy. This was documented by the presence of larvae in the muscles of offspring. However, the rate of this transmission increased when the mothers are infected at late pregnancy whether they were immunosuppressed or not. The administration of the immunosuppressive drug whether before or after pregnancy increased the rate of infection and the mean larval count in both uteri of mothers and muscles of their offspring. A higher percentage of abortion was demonstrated in females infected before mating in different studied groups

comparative efficacy study of praziquantel and albendazole treatment in experimental schistosomiasis

The currently used drug for chemotherapeutic control of schistosomiasis is praziquantel [PZQ]. Albendazole is a broad spectrum antiparasitic drug that showed trematocidal activity. The present study aimed at testing the effect of albendazole on experimental schistosomiasis mansoni infection using PZQ as therapeutic control. Swiss strain albino mice were infected with Schistosoma mansoni [S. mansoni] cercariae. Drugs were given orally on the 45[th] day post infection [PI] for 2 successive days. Mice were sacrificed on the 47[th] day PI and subjected to parasitological and scanning electron microscopic [SEM] studies. Albendazole caused a significant reduction in worm load and those recovered were shorter as measured by the camera lucida. By SEM, perfused S. mansoni albendazole treated worms showed surface tegumental changes. Albendazole is a promising drug for treatment of schistosomiasis

Effect of topical agents on cercariae of schistosoma mansoni

The present work was planed to evaluate the effect of free N, N- diethyl-m- toluamide [DEET], controlled release DEET and white precipitate ointment on the viability of cercariae of S. mansoni in vitro. They were also topically applied to mice to study their efficiency in preventing cercarial skin penetration. Free DEET and controlled release DEET formula caused immobilization and death of cercariae within 20 and 5 min, respectively. The number of adults detected after the application of free DEET and white precipitate ointment to mice skin prior to infection were significantly lower than the control group. When controlled release DEET was applied, no adults could be detected, indicating the failure of cercariae to enter through the skin. This was confirmed by histopathological study of the liver which was free of granuloma. Scanning electron microscopy revealed tegumental changes in cercariae exposed to both free DEET and controlled released DEET. So, topical application of any of the three chemicals was found to be effective in controlling S. mansoni infection. The best was with controlled release DEET