Zoonotic cutaneous leishmaniasis in Saudi Arabia: the incrimination of Phlebotomus papatasi as the vector in the Al-Hassa oasis

Surveys of the phlebotomine fauna in a focus of zoonotic cutaneous leishmaniasis (ZCL) in the Al-Hassa oasis, Eastern Province, Saudi Arabia, revealed only one species of Phlebotomus (P. papatasi) and three of Sergentomyia (S. antennata, S. clydei and S. fallax). 11 specimens of P. papatasi from six sites in the oasis were found with promastigotes in the midgut. An isolate from one of the sandflies was typed by the examination of isoenzymes and identified as Leishmania major, zymodeme LON-4 (= Montpellier zymodeme 26), the principal zymodeme of L. major isolated from patients with ZCL in the oasis. Three isolates from leishmanial lesions at sites of the bites of wild caught specimens of P. papatasi were also identified as the same zymodeme of L. major as the isolate from the sandfly. The findings show that P. papatasi is the vector of ZCL in the Al-Hassa oasis and probably in other ecologically similar foci in the Kingdom.     

Morphometrics and protein profiles of the salivary glands of Phlebotomus papatasi and Phlebotomus langeroni sand flies

Sand fly salivary fluid contains numerous proteins that modulate host immune responses to infection and facilitate blood-feeding and establishing Leishmania infection. Salivary proteins are differentially expressed in adaptation to the host, the meal type and ecological factors. We report on the morphometrics and protein composition of salivary glands of colonised Phlebotomus papatasi and P. langeroni sand flies from Egypt. Female glands were dissected at day 1 (D1, unfed), day 2 (D2, sugar-fed), day 3 (D3, blood-fed) and day 7 (D7, blood-digested). The salivary glands are composed of two lobes: heterogeneous in P. papatasi and homogeneous in P. langeroni. Lobe sizes varied considerably with fly age and feeding state; D3 flies had the largest lobe sizes and protein content. The P. papatasi flies had larger lobes and higher protein content than the P. langeroni flies. The P. papatasi D1 flies had 15 protein bands that decreased in the D2, D3 and D7 flies to 10 bands in the Sinai flies and 9 bands in the Alexandria flies. All P. langeroni flies had 12 protein bands but with different intensities. The results reveal inter-specific variation between P. papatasi and P. langeroni, while no intra-specific variation between P. papatasi strains. These results increase our understanding of salivary gland protein composition and blood-feeding behaviour in Old World sand flies with implications for leishmaniasis epidemiology and control.     

Evaluation of 1-octen-3-ol and carbon dioxide as attractants for Phlebotomus papatasi (Diptera: Psychodidae) in southern Egypt

The effectiveness of 1-octen-3-ol (octenol) as an attractant for collecting medically important psychodids has never been reported. This study evaluated the effects of carbon dioxide (CO2) and octenol released at 2 rates, individually and in combination, as attractants for adult sand flies in a small village in southern Egypt. Four sand fly species were collected: Phlebotomus papatasi, P. sergenti, Sergentomyia palestinensis, and S. schwetzi. Only P. papatasi was collected in numbers sufficient to allow statistical analysis. This study reaffirms that CO2 is an effective attractant for female P. papatasi and also demonstrates that neither male nor female P. papatasi respond to octenol alone. Additionally, no synergistic attractancy for either females or males was observed when CO2 and octenol were combined.     

Susceptibility of Phlebotomus papatasi (Diptera: Psychodidae) to DDT in some foci of cutaneous leishmaniasis in Iran.

The susceptibility of Phlebotomus papatasi to DDT was studied in field surveys at localities in different areas of Iran during 1985-88. In many parts of Iran houses had been treated with DDT for malaria control (1950-68). Tests were carried out in localities where the application of DDT had been discontinued since 1969. This investigation showed that P. papatasi from Isfahan is more tolerant to DDT than flies from other areas, probably a manifestation of DDT resistance.     

New record of Phlebotomus sergenti, the vector of Leishmania tropica, in the southern Nile valley of Egypt.

We report the 1st collection of Phlebotomus sergenti, a vector of the cutaneous and visceralizing forms of Leishmania tropica, from southern Egypt. Four female and 1 male P. sergenti were collected from unlit Centers for Disease Control light traps placed in a village on the Nile River, 6 km north of Aswan, Egypt, during studies conducted from 1998 to 1999. This extends the known distribution of this species farther south in Egypt than previously recorded.     

Leishmaniasis in Israel: reservoir hosts, sandfly vectors and leishmanial strains in the Negev, Central Arava and along the Dead Sea

The reservoir animals, sandfly vectors and strains of Leishmania from foci in the southern region of Israel were studied. The rodent host species are: Psammomys obesus, Meriones crassus and probably Nesokia indica. The vector species are Phlebotomus papatasi, which were caught at all collecting sites and Ph. sergenti, which were collected in the area of the Dead Sea and in the Central Arava. Strains of Leishmania major isolated from rodents, vectors and man were serologically and enzymologically identical with regard to their excreted factor (EF) serotypes, their malate dehydrogenase (MDH), glucose-phosphate isomerase (GPI) and glucose-6-phosphate dehydrogenase (G6PDH) enzyme variant types, but exhibited three variant subtypes of 6-phosphogluconate dehydrogenase (6PGDH). The distribution of the 6PGDH subtypes correlates with three different geographical locations. Scarcity of water is the main factor limiting the biotopes of the sandflies and the spread of leishmaniasis. The subjects discussed are the dependence of sandfly distribution on rodent-burrow depth in arid areas and the inter-relationship between the leishmanial subtypes, vectors and hosts.     

Frequency of Wolbachia infection in laboratory and field sand fly (Diptera: Psychodidae) populations

Using a polymerase chain reaction (PCR) assay with primers designed for the Wolbachia 16S rRNA and outer surface protein (wsp) gene, we screened 11 laboratory colonies and 4 field samples of 6 sand fly species for Wolbachia infection. Infection was only detected in 3 laboratory colonies of Phlebotomus papatasi Scopoli, originally collected in Israel, Egypt, and Saudi Arabia.     

Testing insecticide susceptibility of Phlebotomus perniciosus and P. papatasi (Diptera: Psychodidae) in Italy

A study was undertaken to establish the susceptibility of two recently colonized sand fly species, Phlebotomus perniciosus and P. papatasi to some insecticides. A laboratory colony of P. papatasi, unexposed to insecticides for a period of ten years, was used as reference strain. Bioassay tests were carried out according to the WHO standard protocols based on the mortality rates recorded at different exposure times. Serial (from 1 to 60 min) exposures to DDT 2%, lambda-cyhalothrin 0.06% and permethrin 0.2% were tested on groups of 30 adult sugar-fed female sand flies, for a total of 7,470 specimens. Data were subjected to probit analysis and the susceptibility was calculated at LT50 and LT95 by comparison with the laboratory reference strain. The LT50 values for P. perniciosus were 19.9, 3.2 and 6.9 min, and for P. papatasi 18.0, 7.4 and 11.0 min, using DDT, lambda-cyhalothrin and permethrin, respectively. The results showed that two Italian populations of P. perniciosus and P. papatasi from Campania region and from Rome, respectively, are susceptible to the insecticides tested as compared with the reference strain used.     

Phylogeography of the subgenus Transphlebotomus Artemiev with description of two new species,Phlebotomus anatolicus n. sp. and Phlebotomus killicki n. sp.

The subgenus Transphlebotomus comprises sand fly species with distribution markedly restricted to the Mediterranean basin and suspected of Leishmania transmission. Only three species, Phlebotomus mascittii, Phlebotomus canaaniticus and Phlebotomus economidesi, have been described up to the present. Due to their similar morphology, proper identification remains difficult and relies mainly on molecular markers. We studied sand fly species of this subgenus from Crete and south-western coast of Anatolia. Based on the sequencing analysis of mitochondrial genes (cytochrome b, NADH dehydrogenase subunit 4, cytochrome oxidase I), two new Transphlebotomus species were identified and subsequently distinguished also by morphological characters: Phlebotomus anatolicus n. sp. and Phlebotomus killicki n. sp. Moreover, Ph. economidesi, previously only recorded from Cyprus, was found in Turkey sympatrically with these two new species. Based on the divergence time estimates, the first split has occurred in the subgenus Transphlebotomus ∼10 million years ago and the paleogeographic events took place around the Aegean and Mediterranean regions were suggested as the main drivers of the diversification of the subgenus. Our findings indicate that for Transphlebotomus species, morphological identification should be confirmed by molecular approaches, especially for investigations concerning their possible vectorial role in Leishmania transmission.     

Host preference of Phlebotomus argentipes and Phlebotomus papatasi in different biotopes of West Bengal, India

Host preference Phlebotomus argentipes and Phlebotomus papatasi in different biotopes was investigated in two highly endemic Kala-azar districts of West Bengal, India for a better understanding of the transmission dynamics. Blood meals of 304 P. argentipes and 206 P. papatasi, collected from different biotopes from two Kala-azar affected districts in West Bengal, were tested against seven different antisera by modified Ouchterlony gel diffusion techniques. It appeared that host preference of P. argentipes varied widely in different biotopes, which is mainly zoophilic (62.80%), preferring to feed on man as the second choice (24.92%); however it is also a "chance feeder" according to biotopes. Multiple blood meals are also prevalent in P. argentipes at a much higher rate than that of P. papatasi. The implication in relation to epidemiological significance has been discussed.     

Etymologia - Leishmaniasis

Disease caused by protozoan parasites of the genus Leishmania, named in 1901 for British Army doctor William Leishman, who developed a stain to detect the agent. It is transmitted by the bite of certain species of sand fly, including the genus Lutzomyia in the New World and Phlebotomus in the Old World.     

Zoonotic cutaneous leishmaniasis in Saudi Arabia: lesions healing naturally in man followed by a second infection with the same zymodeme of Leishmania major

A patient with a previous history of an infection with Leishmania b. braziliensis contracted zoonotic cutaneous leishmaniasis (ZCL) in the Al-Hassa oasis, Eastern Province, Saudi Arabia. Five lesions healed spontaneously over a period of 40 weeks without treatment. A year after acquiring ZCL he became infected again in the same focus. Isolates of parasites at both episodes were identified as L. major, zymodeme LON-4. Compared with the first infection of ZCL, parasites were fewer in the lesions on the second occasion, the lesions were smaller and healing was quicker (10 weeks). This work and a previous report of patients with active lesions and leishmanial scars suggest that second infections of L. major are not uncommon in the oasis where no autochthonous infections of other species of Leishmania have yet been recorded in man and only one species of Phlebotomus (P. papatasi) is known.     

Leishmania in the Old World: 1. The geographical and hostal distribution of L. major zymodemes

135 stocks of Leishmania major from man, reservoir hosts and sandflies were characterized using thin-layer starch-gel electrophoresis of 13 enzymes: MDH, 6PGD, GD, SOD, ASAT, ALAT, PK, PGM, ES, NH, PEPD, MPI, GPI. Homogeneity in this species was demonstrated by identical electrophoretic mobilities in nine enzymes. Polymorphism in four enzymes: 6PGD, GPI, PEPD, ES, gave six zymodemes among the collection. Stocks from sandflies and several species of burrowing rodents were indistinguishable from those from man in the same areas. Stocks of Leishmania from North-West India were identified as L. major. In some foci the distribution of zymodemes has some correlation with the presence of particular rodent reservoir hosts. The enzymic homogeneity of L. major throughout its geographical and host range appears to be correlated with the close association between L. major and sandflies of the subgenus Phlebotomus. The status of L. major as a distinct species is supported.     

Distinct transmission cycles of Leishmania tropica in 2 adjacent foci, Northern Israel

Transmission of Leishmania tropica was studied in 2 adjacent foci in Israel where vector populations differ. Only Phlebotomus sergenti was found infected with L. tropica in the southern focus; P. arabicus was the main vector in the northern focus. Rock hyraxes (Procavia capensis) were incriminated as reservoir hosts in both foci. L. tropica strains from the northern focus isolated from sand flies, cutaneous leishmaniasis cases, and rock hyraxes were antigenically similar to L. major, and strains from the southern focus were typically L. tropica. Laboratory studies showed that P. arabicus is a competent vector of L. tropica, and P. sergenti is essentially refractory to L. tropica from the northern focus. Susceptibility of P. arabicus may be mediated by O glycoproteins on the luminal surface of its midgut. The 2 foci differ with respect to parasites and vectors, but increasing peridomestic rock hyrax populations are probably responsible for emergence of cutaneous leishmaniasis in both foci.     

Susceptibility of sand flies to selected insecticides in North Africa and the Middle East

The purpose of this study was to determine the baseline susceptibility of 4 species of phlebotomine sand flies from North Africa and the Middle East to various insecticides. Susceptibility was determined using the World Health Organization test kits for measuring resistance in mosquitoes exposed to insecticide-impregnated papers. Fifty, 90, and 99% lethal doses were calculated for bendiocarb, cyfluthrin, DDT, malathion, permethrin, and resmethrin on Phlebotomus bergeroti, P. langeroni, P. papatasi. and P. sergenti. The least toxic insecticide to all species was DDT, followed by malathion and permethrin in order of increasing toxicity. Cyfluthrin was the most toxic to P. langeroni and P. papatasi, followed by resmethrin and bendiocarb in order of decreasing toxicity. Resmethrin exhibited the highest toxicity to P. bergeroti followed by cyfluthrin and bendiocarb, whereas bendiocarb was most toxic to P. sergenti, followed by cyfluthrin and resmethrin in order of decreasing toxicity. An attempt was made to obtain data for deltamethrin, but close response data were insufficient to determine regression lines for this insecticide on these species. However, analysis of preliminary data indicated that deltamethrin is highly toxic to these sand flies.     

Isolation of Leishmania tropica from an Ethiopian cutaneous leishmaniasis patient

Cutaneous leishmaniasis (CL) in the Old World is caused mainly by three species of Leishmania: L. major, L. tropica and L. aethiopica, and sporadically by L. infantum and L. donovani. In Ethiopia, zoonotic cutaneous leishmaniasis, caused by L. aethiopica, is a major public health problem affecting thousands of people in the highlands. By contrast, little is known about the existence and epidemiology of CL due to L. tropica. In this report, we provide the first well-documented case of CL in Ethiopia caused by L. tropica. The patient acquired the infection in Awash valley of the Ethiopian Rift Valley (northeastern Ethiopia), where Phlebotomus sergenti and P. saevus have previously been found infected by L. tropica. Using the isoenzyme electrophoresis technique, the isolate was found to belong to a variant of L. tropica zymodeme MON-71, one of the new zymodemes found in Ethiopia from P. sergenti in the same region so far. The epidemiological implications of the finding are discussed.     

Leishmania infecting man and wild animals in Saudi Arabia. 1. General survey

Using up to 13 enzymes, biochemical characterization of 75 isolates of Leishmania made from man, wild animals and sandflies from a wide variety of localities in the Kingdom of Saudi Arabia has revealed the presence of L. major (two similar zymodemes), L. tropica (two zymodemes) and a parasite of the L. donovani-L. infantum complex. Zymodeme LON-4 of L. major has been found in 52 of 53 isolates so far characterized from man, from one specimen of Phlebotomus papatasi, from 15 Psammomys obesus, from one Meriones libycus and from one dog. One isolate from man has been identified as a new variant of L. major. This variant, zymodeme LON-65, varies from zymodeme LON-4 in a single enzyme. While this is the only example of zymodeme LON-65 identified so far, zymodeme LON-4 has also been obtained from Kuwait and Iraq. These are the first reports of L. major in Meriones libycus from Saudi Arabia and the first proven isolate from the dog in any country. L. tropica was identified from only two foci, whereas L. major appears to be widely distributed in the Kingdom. Two infants with kala-azar were found to be infected with a parasite apparently identical to zymodeme LON-42 of L. donovani (sensu lato) which also occurs in the highlands of Ethiopia.     

Released glycoconjugate of indigenous Leishmania major enhances survival of a foreign L. major in Phlebotomus papatasi

The effect of Leishmania glycoconjugate in the vector was investigated using Phlebotomus papatasi artificially infected with a Leishmania major strain that this vector does not transmit in nature. Glycoconjugate of the vector-specific strain of L. major was added to the infective meals of some fly groups and the success of infections with or without this substance was compared 4 d later. In the absence of glycoconjugate the parasites survived in 15.6% of the flies, while the addition of 0.5 mg/ml and 2 mg/ml raised the rate of infection to 34.3% and 63.0% respectively. Undigested blood was found in the stomach of 7.8% of the infected flies, whereas following meals with parasites and 2 mg/ml glycoconjugate it was present in 37% of the flies. The results demonstrated that this glycoconjugate increased the viability of the parasites in the unsuitable vector and delayed digestion of the infective meals. In a parallel experiment the glycoconjugate of L. donovani did not affect the survival of the parasites.     

The potential effect of global warming on the geographic and seasonal distribution of Phlebotomus papatasi in southwest Asia.

The distribution of Phlebotomus papatasi in Southwest Asia is thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming, temperature values for 115 weather stations were increased by 1 degree C, 3 degrees C, and 5 degrees C, and the outcome variable coded as unknown in the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May, June, July, and August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations, 71 (62%) would be considered endemic with current temperature conditions; 14 (12%) additional stations could become endemic with an increase of 1 degree C; 17 (15%) more with a 3 degrees C increase; and 12 (10%) more (all but one station) with a 5 degrees C increase. In addition to increased geographic distribution, seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3 degrees C rise in temperature and in 29 (25%) locations with a 5 degrees C rise.     

Vertical stratification of phlebotomine sandfly fauna (Diptera,Psychodidae) in a primary non-flooded forest of the Central Amazon,Amazonas State,Brazil

Studies on the vertical stratification of phlebotomine sandfly fauna were conducted in a non-flooded primary forest at a Tropical Forest Experimental Station of the National Institute of Amazonian Research from October 1998 to March 1999. CDC light traps were placed at one, 10, and 20 meters above ground. A total of 2,859 sandflies were captured, belonging to the Lutzomyia (99.93%) and Brumtomyia (0.07%) genera, represented by 38 species. In the Lutzomyia gender, the most frequent sub-gender was Nyssomyia (43.4%), followed by Psychodopygus (22.8%). Lutzomyia umbratilis, L. anduzei, L. rorotaensis, L. trichopyga, and L. olmeca nociva predominated at one meter above ground, while L. davisi, L. infraspinosa, L. umbratilis, L. trichopyga, and L. anduzei predominated at 10 meters. L. anduzei, L. tuberculata, L. dendrophyla, and L. dreisbachi were the most abundant species at 20 meters. L. umbratilis, which appeared at all three levels of vertical stratification, has great epidemic significance as a vector of Leishmania (Viannia) guyanensis.