Natural infections of Leishmania major in domestic dogs from Alexandria, Egypt.

Two leishmanial isolates from dogs from Alexandria, Egypt, were typed serologically and biochemically as Leishmania major. This is the second time that L. major has been shown to occur in dogs. The significance of these findings as a misleading phenomenon in relation to the relatively recent outbreak of infantile kala-azar in the area of Alexandria is discussed.

The influence of Bacillus sphaericus on the biology and histology of Phlebotomus papatasi.

This work was achieved to study the impact of B. sphaericus treatment on some biological aspects of P. papatasi. Contaminated larval food with B. sphaericus (strain-2362) in different concentrations was offered in the laboratory for P. papatasi and also the latent effect on the fecundity of survived females from previously treated larvae. There was a decrease in the survived numbers of immature stages and adults correlated to the concentrations, while there was no obvious change in the larval and pupal durations compared to the control. The fecundity of females survived from previously treated larvae, was sharply decreased. Many variations was noticed in the examined tissues of mid-gut, fat tissues, and Malpighian tubules, although no bacteraemia was detected.

Leishmania infection sought in rodents in north Sinai, Egypt.

Zoonotic cutaneous leishmaniasis (ZCL) is endemic in certain foci in North Sinai. In the present study, eight species of commensal and wild rodents were trapped from seven areas. Suggestive ZCL lesions were seen on R. rattus, R. norvegicus, G. pyramidum, G. ander soni, G. gerbillus and Meriones sacramenti. Positive Giemsa stained smears were identified in G. pyramidum. The results were discussed. It was concluded that the ZCL transmission cycle, animal reservoirs, sand fly vector and man, is documented.

Preliminary observations on cross-mating of the malaria vector, Anopheles sergentii from two Egyptian oases.

Intra- and inter-strain crosses were made between randomly collected adults Anopheles sergentii originated from Tersa village (El-Faiyum Governorate) and Siwa oasis (Matruh Governorate). The success of such crosses and their effects on fecundity and fertility of the parental females and on survival and development velocities of the F1 immatures were examined. No overall heterosis effects on such attributes were detected suggesting absence of genetic differences between the vector populations in these two malarious areas.

Experimental efficiency of Phlebotomus papatasi in maintaining development of four species of Leishmania.

Experimental infections were carried out to evaluate the capability of 3 species of Phlebotomus to acquire and allow development of 4 species of Leishmania. The sand-flies were allowed to feed on infective blood by a membrane feeding technique and infected vertebrate hosts. The species of Phlebotomus experimented with were P. papatasi (Egyptian and Indian strains), P. dubosqi (Sinegal strain), and P. perniciosus (French strain). The species of Leishmania used were L. tropica (Afganistanian strain) in blood and L. major (Egyptian strain) in blood, in volunteer patient and in hamster, L. major (Morocco strain) in Meriones shawi, L. infantum (French strain) in dog and L. enrietti (Brazilian strain) in Guinea-pig. The results showed that Egyptian P. papatasi was the most suitable species for Egyptian L. major in blood followed by P. dubosqui. On the other hand, P. dubosqui was the most suitable species for L. tropica in blood followed by Indian P. papatasi. On the other hand, Egyptian P. papatasi acquired L. major from hamster (38.2%) and L. enrietti from Guinea pig (1.9%), but not L. major from the patient. Indian P. papatasi acquired L. major from Meriones (5.6%), L. infantum from dog (1.09%) but not L. enrietti from Guinea pig. Generally speaking, L. major was more engalfed by P. papatasi (2 strains) from the artificial source (blood) than from the vertebrate hosts.

Two successive years studies on Phlebotomus papatasi in North Sinai Governorate, Egypt.

No doubt, zoonotic cutaneous leishmaniasis (ZCL) is increasing in North Sinai Governorate. The causative agent, L. major was identified as well as two animal reservoir hosts, Gerbillus pyramidum and Meriones crassus. This paper was intended to study the seasonal abundance and the sex ratio of the suspected insect, Phlebotomus papatasi as well as to search for natural infected in wild caught females. The C.D.C. miniature light traps were used for adult collections, dissection was used for demonstration of the promastigotes and biochemical typing was used for identification of isolated strain. The results showed that (a) the seasonal activities started in April and ended by the end of November, with a well marked bimodal distribution in one year, (b) the sex ratio (male to female) 1:2.9 (c) 0.14% of 4208 females were naturally infected with promastigotes and typing proved to be Leishmania major, zymodeme LON 70.

Psammomys obesus Cretzschmar, 1828 and zoonotic cutaneous leishmaniasis in Sinai Peninsula, Egypt.

In the Middle East, the fat sand rat Psammomys obesus is the most important reservoir host of zoonotic cutaneous leishmamiasis (ZCL). It is the most incriminated host in outbreaks. Two P. obesus caught in Wadi El Gedeiret (Al Arish, North Sinai) were found naturally infected with Leishmania major as indicated by enzyme electrophoresis. In Egypt, the already known reservoir hosts are Gerbillus pyramidum I. Geoffroy St. Hilaire, 1825; Meriones crassus Sundevall, 1984 and Meriones sacramenti Thomas, 1922. The hostal role of P. obesus was discussed.

Bacillus thuringiensis var. israelensis as a microbial control agent against adult and immature stages of the sandfly, Phlebotomus papatasi under laboratory conditions.

The laboratory treatment of adult and immature stages of Phlebotomus papatasi by the bacterial insecticide, Bacillus thurnigiensis var. israelensis was carried out. Different concentrations of B.t.i. mixed with fructose and glucose were assayed against the adult sandfly, while the immature stages were treated by offering larval diet contaminated by B.t.i. in different concentrations diluted by distilled water. B.t.i. could induce mortality to half of the larval and pupal population at 0.26 x 10(-5) g/L. The median lethal doses of adults which were fed on contaminated surgery diet with serial dilutions of B.t.i. were 1.3 x 10(-2) g/L with fructose, and 3 x 10(-2) g/L with glucose after 48 and 72 hrs. The longevity period of larvae and pupae fed on contaminated larval diet showed negative correlation with bacterial concentrations except for highly concentrations. The bacterial control of the sandfly, Ph. papatasi could be recommended particularly as adulticide agent.

The discovery and preliminary characterization of a novel trypanosomatid parasite from Rattus norvegicus and stray dogs from Alexandria, Egypt.

A survey of rodents and dogs was carried out in Alexandria and its environs to see if an animal reservoir was associated with an outbreak of infantile kala-azar in this area. Three rodent species, Rattus rattus, Rattus norvegicus and Mus musculus, were commonly trapped and examined. A flagellate parasite was isolated from the spleens of two R. norvegicus. It was typed serologically by excreted factor serotyping and enzymologically by thick starch electrophoresis of four of its enzymes: GPI, G6PD, 6PGD and PGM. The same type of parasite was also isolated from two stray dogs from the same vicinity. This flagellate was quite distinct from Leishmania donovani, Leishmania major and Leishmania tropica, the three common Old World species of Leishmania; but its exact identity remains uncertain. It could be a new leishmanial entity or a flagellate parasite of another genus.