EFFECT OF DIFFERENT BLOOD SOURCES ON THE FEEDING TIME OF SAND FLY, PHLEBOTOMUS PAPATASI.

The feeding time for sand fly females was determined experimentally by feeding of thirty females (3-5 days-old) sand fly Phlebotomus papatasi on different blood sources (human, pigeon, hamster and blab C mice). Mean feeding time was longest on blab C mice, 8.55 minutes, followed by hamster, 7.05 minutes, then pigeon, 4.84minutes, and finally human, 4.69 minutes. Significant difference was observed in the feeding time between females fed on hamster and balb c mice but there is no significant difference between females fed on human and pigeon.

Natural and experimental evidence of viscerotropic infection caused by Leishmania tropica from North Sinai, Egypt.

Cutaneous leishmaniasis (CL) is a neglected clinical form that is quite prevalent in Eastern North parts of the country in Sinai Peninsula. Leishmania tropica was identified by previous reports as the causative agent responsible for viscerotropic infections in-patients and experimental animals. Here, we reported the viscerotropic infections from naturally infected rodent Gerbillus pyramidum floweri collected from North-Sinai. Footpad and tail lesions, spleenomegaly, and malformed dark-colored spleen were the characteristic CL symptoms. The spleen of the rodent found positive to amastigote impression smear. ITS-1 DNA was sequenced and revealed 100% identity of the strain in the current study to the other L. tropica sequences identified from the patients with the suspected CL and inhabited the same study area. The current findings confirmed the susceptibility of gerbil to L. tropica, and raise the concerns for the role of rodents as accidental host suffering the infections. The susceptibility of wild and experimental rodents to the same L. tropica strain was also investigated; BALB/c and G. pyramidum were more susceptible to L. tropica (24.33 ± 4.37 and 25 ± 4.58 days post-infection, respectively). Similar viscerotropic pathologies were reported in experimental infection of only golden hamster (≈ 120 days post-infection), and G. p. floweri (≈ 160 days post-infection).

Transmission of Leishmania infantum MON-98 to hamsters by the bite of Phlebotomus langeroni Nitzulescu (Diptera: Psychodidae).

The ability of Phlebotomus langeroni to successfully acquire and transmit Leishmania infantum MON-98 to hamsters was demonstrated. Sand flies and Leishmania both originated from an infantile visceral leishmaniasis focus in El Agamy Egypt. P. langeroni females were infected by feeding on lesions of needle-inoculated hamster and on infected blood suspension using a chick-skin membrane apparatus. Infection rate of sand flies fed on membrane was 88% compared to 7.8% for flies fed on leishmanial lesion. The transmission to hamster took place by the bites of infective flies taking a second blood meal, on the 8th to 10th day post-feeding. Furthermore, successful transmission was by the bites of flies that took no blood or that took full blood meal. Whereas flies that took full blood meal were not infective as indicated by dissection. In three hamsters, lesions developed after three months. Leishmania amastigotes were demonstrated from the lesion as well as from the liver and spleen of infected hamsters.

First report of Leishmania tropica from a classical focus of L. major in North-Sinai, Egypt.

Cutaneous leishmaniasis (CL) is prevalent in the Egyptian Sinai Peninsula and previous research has consistently documented the etiologic agent to be Leishmania major. We report the first isolation of Leishmania tropica from human cases of CL in a Northern Sinai community bordering Palestine. Parasite culturing, real-time polymerase chain reaction (PCR), gene sequencing, and restriction fragment length polymorphism (RFLP) analyses indicate CL cases in this community were caused by either L. major or L. tropica (three cases each). Two wild-caught rodents (Gerbillus pyramidum floweri) were infected with L. tropica. Phlebotomus papatasi sand flies were found harboring L. major, however only non-infected individuals of Phlebotomus sergenti, a vector for L. tropica, were caught. Patients with L. tropica had not traveled from the region in over a year, suggesting these cases are autochthonous. This scenario is consistent with an incursion of L. tropica from bordering countries and raises concerns about expansion of this parasite further into Egypt.

Attachment of Leishmania major and Leishmania infantum in the midgut of their respective sand fly vectors Phlebotomus papatasi and Phlebotomus langeroni (Diptera: Psychodidae).

The attachment of Leishmania infantum and Leishmania major in the midgut of experimentally infected Phlebotomus langeroni and Phlebotomus papatasi was examined by transmission electron microscopy. Cellular damage in the midgut of infected flies as a byproduct of infection was observed in both species. A difference in the mode of attachment of flagella to the midgut of their respective sand fly vectors suggested higher adaptation between L. major/P. papatasi compared to L. infantum/P. langeroni.

Human zoonotic cutaneous leishmaniasis and associated sand flies (Diptera: Psychodidae) in Sheikh Atiya village, southern Sinai, Egypt.

Zoonotic cutaneous leishmaniasis is endemic in Sinai Peninsula. Human cases were recorded from the northern Sinai, however little was known about the disease in southern Sinai. During entomological surveys conducted southern Sinai in summers of 1997-1999, a clinically confirmed ZCL case was encountered for the first time in Sheikh Atiya village in June 1999. The parasite was isolated and identified as L. major using cellulose acetate electrophoresis. A total of 784 phlebotomine sand flies were collected. Sand fly species composition at Sheikh Atiya village showed that P. papatasi and P. alexandri were the most abundant species in the area and each comprises about 47 % of the flies collected. P. sergenti and P. kazeruni occurred in very low numbers. All the female flies dissected (N = 304) were negative for any Leishmania-like flagellates. When the identified isolate was inoculated in the footpads of a clean laboratory colonized Acomys cahirinus dimidiatus, a lesion was developed on the site of inoculation 9 months post injection. The role of P. alexandri and A. c. dimidiatus in transmission of leishmaniasis in southern Sinai remains questionable. Environmental factors contributed to the appearance of ZCL in the area are discussed.