Prevalence of Some Human Enteroparasites in Commonly Consumed Raw Vegetables in Tabuk, Saudi Arabia.

The problem of parasitic contamination of food, especially fresh vegetables, is not limited to personal hygiene during food preparation but is also widely dependent on the source of the food and the handling it undergoes before it gets to the consumer. The objective of the present study was to evaluate parasitic contamination in eight common raw vegetables in Tabuk, Kingdom of Saudi Arabia. A total of 400 samples of raw vegetables obtained from wholesale and retail markets were examined for helminth eggs and larvae and for cysts of different parasites, using standard methods. The prevalence of the parasites was 20.65% in cucumber, 15.76% in cabbage, 14.67% in pea, 14.13% in cress, 13.04% in lettuce, 10.33% in carrot, 8.70% in green onion, and 2.72% in tomato. Statistical analysis showed a significant difference (P < 0.05) for Entamoeba spp. cysts, Ascaris lumbricoides eggs, Entamoeba coli cysts, and unknown isolated parasite cysts. Parasites are common in vegetables that are frequently eaten raw and, for this reason, may pose a health risk for consumers in Tabuk.

Detection of tick blood parasites in Egypt using PCR assay II- Borrelia burgdorferi sensu lato.

The prevalence of Borrelia burgdorferi sensu lato (s.l.), the etiologic agent of Lyme borrelosis (LB), was determined for the first time in Egypt by using polymerase chain reaction (PCR). Questing 5243 hard and soft ticks were collected from animal farms throughout Giza Governorate. DNA from 500 individual tick species was extracted and PCR was performed. Primers verified from the sequence of German strain Pko of Borrelia afzelii were used. Fragments of 642 bp were generated and sequenced. The prevalence of B. burgdorferi sensu lato (s.l.) was 28% of examined soft and hard ticks. High infection rate (66%) of B. burgdorferi s.l. was observed in both nymph and adult soft ticks Ornithodoros savignyi. Beside, the role of hard ticks as potential vectors of Lyme disease in Egypt, where the infection rate was between 0.0-50.0%. Sequence analysis of PCR product of Borrelia burgdorferi sensu lato shares high degree of similarity in sequence compared to similar species in GenBank.

[The occurrence of Cryptosporidium spp. in synanthropic flies in urban and rural environments]. / Wystepowanie Cryptosporidium spp. u muchówek synantropijnych na wybranych stanowiskach miejskich i wiejskich.

This study was carried out to determine the role of non-biting synanthropic flies as carriers of Cryptosporidium spp. oocysts in the vicinity of the city of Gdansk (NE Poland). In 2001-2003, flies were collected from three breeding sites: cow sheds and meadows in the Bystra cattle farm and municipal landfill Szadólki using inhaustors (aspirators) and entomologic nets. A total of 2358 specimens of the families: Muscidae (n = 1598), Calliphoridae (n = 739) and Sarcophagidae (n =21) were collected and analysed in 249 pools consisted of 9.5 insects, in average. Microscopic examination was used to detect Cryptosporidium spp. oocysts in the fly faeces deposited on the glass microscope slides and stained by Zhiel-Nielsen method. The mean number of faecal droplets per one glass slide was 11.5. Ooocysts of Cryptosporidium spp., stained from light pink to bright red, were found in fly faeces deposited on 25 (27.5%) of 91 glass slides checked. The highest prevalence of the pathogen was observed in faecal droplets deposited by flies collected in municipal landfill (50% investigated slides). DNA of Cryptosporidium spp. was extracted from the surface eluants of flies and/or their gut homogenates and purified. Then extracts were examined by PCR using CPB-DIAGF and CPB-DIAGR primers amplifying a variable region SSU-rRNA of all Cryptosporidium species. Altogether 387 isolates, 228 from surfaces and 159 from gut homogenates, were obtained from 249 pools of flies and analyzed. A specific 435 bp fragment of DNA was obtained in 49 (12.7%) lysates tested. In 10.4% pools, DNA of the pathogen was detected only in the surface eluants while in 7.6% only in gut extracts. In the case of two pooled samples (0.8%) Cryptosporidium spp. was found in both types of lysates. In total, Cryptosporidium spp. was detected in 47/249 pools of flies (18.9%). Assumed that each positive pool contained just one infected fly, the percentage of specimens able to oocysts transmission were calculated at the minimal level 2.0% (n = 47/2358). The result confirm that synanthropic flies can harbour oocysts of Cryptosporidium spp. both externally and internally, and disseminate them mechanically in the environment. Therefore, under unsanitary conditions they could be involved in the transmission of human and animal cryptosporidiosis.

Sarcosaprophagous flies in Suez governorate, Egypt IV--persistence of human pathogenic bacteria in the developmental stages.

The persistence of three species of human pathogenic bacteria (Escherichia coli, Shigella sonnei and Staphylococcus epidermidis) in sterile artificially fed larvae was examined till adult emergence after ingestion by three species of sarcosaprophagous flies (House fly, Musca domestica, Oriental latrine blow fly, Chrysomya megacephala and Australian cheep blow fly, Lucilia cuprina). The number of bacteria present in mature maggots, pupae and emerging adults declined significantly (P < 0.05). Each human pathogenic bacteria when introduced into a sterilized larval medium, was routinely recovered from larvae (10(5)), pupae (ranged from 10(3) to 10(4) and the majority of emerging flies retain 102 bacteria, whereas some are sterile. The potentiality of emerged flies to harbor bacteria is clearly different (M. domestica > C. megacephala > L. cuprina). No detection for S. epidermidis from emerged C. megacephala and L. cuprina flies, moreover S. sonnei was not detected in the emerged flies of L. cuprina.

Experimental transmission of Hepatozoon gracilis (Wenyon, 1909) com. nov., in its natural host the bean skink lizard (Mabuya quinquetaeniata quinquetaeniata) and vector Culex (C.) pipiens (Diptera: Culicidae).

The bean skink lizard Mabuya quinquetaeniata quinquetaeniata (Family: Scincidae) collected from Abu-Rawash, Giza was infected with the protozoon Hepatozoon gracilis. The mean percent of infection rate all over the year was 12.57% with the highest peak was in October (33%), meanwhile the lowest infection rate was detected in June (2.1%) and no infection was detected in February. Microscopical examination of experimentally infected Culex (C.) pipiens L smears revealed the presence of gamogony and sporogony stages of H. gracilis in their haemoceal. Cx. pipiens was capable to transmit H. gracilis to non-infected M. q. quinquetaeniata under laboratory conditions (21 +/- 1 & 60-70% R.H) after a prepatent period of 32 +/- 1 days from the infective bite. Various developmental schizogony stages were detected both in the lung endothelial cells and liver parenchymal cells. Developmental stages of H. gracilis in both vector or vertebrate host were described. Cx. pipiens was unable to transmit H. gracilis to snake, Psammophis schokari present in the same area of the bean skink lizard.

The effects of laboratory Hepatozoon gracilis infection on the fecundity, mortality and longevity of Culex (Culex) pipiens Linneaus (Diptera: Culicidae) in Egypt.

Laboratory observations on the effect of Hepatozoon gracilis on the egg production of the mosquito Cx. (Cx.) pipiens Linneaus under laboratory conditions revealed that H. gracilis infected mosquitoes produced significantly fewer eggs than uninfected ones. The egg production decreased as parasite burdens increased. Reduction in blood meal size in infected females did not reduce fecundity. No size differences was detected between oocyst-infected and uninfected females although sporozoite positive females were significantly large. Preoviposition period was affected significantly, while incubation period and percentage of egg hatching showed no significant changes. The longevity of female infected mosquitoes decreased insignificantly than in uninfected ones.

Sarcosaprophagous flies in Suez province, Egypt. I--Seasonal distribution and sex-ratio.

Seasonal field studies on 4 bait traps (Fish, Bovine-lung, Grapes and Molasses) were conducted in El-Arbaeen fish-market, El-Arbaeen district, Suez governorate Egypt in 1999 and 2000 to describe the pattern and sex-ratio of sarcosaprophagous flies. The presence of sarcosaprophagous flies (Calliphoridae, Muscidae and Sarcophagidae) revealed that Chrysomya megacephala (Fabricius), Lucilia cuprina (Wiedemann) and Musca domestica (Linnaeus) were the most dominant flies. Almost equal number of male and female flies of C. megacephala, L. cuprina and M. domestica trapped on baits of grapes and molasses, possibly represent real proportion of male and female population of these flies. The number of female flies recorded on fish and bovine-lung baits was significantly higher than those recorded on grapes and molasses. As row fish and bovine-lung are important breeding media for flies, they may have attracted a larger number of female flies for ovary maturation and oviposition.