Specification of blood meals ingested by female sand flies caught in Palestinian foci and identification of their concomitant leishmanial infections

Abstract

Since leishmaniases are zoonotic vector-borne diseases transmitted through the bites of infected female sand flies, identification of the sources of imbibed blood meals and the detection and identification of leishmanial DNA in them are important in discerning animal reservoirs, clarifying the epidemiology and facilitating control of local leishmaniases. CDC light traps, aspirators and sticky paper traps were used to collect sand flies in four Palestinian foci of both, CL and VL. Phlebotomine species identification was based on morphological keys. Female specimens were screened to detect and identify leishmanial infections, using kDNA-PCR and ITS1-PCR, and engorged female specimens were analyzed to identify the origin of their blood meals, using an RDB blood meal assay based on the amplification of the cytochrome b gene (cytb) of vertebrate mitochondrial DNA (mtDNA). Twenty sand fly species, 11 of the genus Phlebotomus and nine the genus Sergentomyia, were identified. The most abundant species was Ph. papatasi (33.7%), followed by Ph. sergenti (21%). Among the 691 female sand fly specimens, 18.5% (128/691) were positive for leishmanial DNA, using the kDNA-PCR and 6.4% (44/691) were positive using the ITS1-PCR. DNA from parasites of the genus Leishmania was identified in only 1.5% of the infected sand flies. That of Leishmania tropica parasites was detected in six female specimens of Ph. sergenti and that of L. major parasites in two female specimens of Ph. papatasi. Interestingly, two engorged females of the species Se. (Neophlebotomus) sp. were positive for L. tropica DNA. Ninety engorged female sand flies of Ph. papatasi and 104 of Ph. sergenti had fed on a large variety of vertebrate hosts such as humans, hyraxes, rats, cows, goats and birds. Regarding blood-meals showing a mixture from different species of animal host, hyrax and rat blood was revealed in 8/104 (7.7%) females of Ph. sergenti. Detection of hyrax blood in engorged female sand flies of the species Ph. sergenti supports the role of hyraxes being a potential reservoir of L. tropica in Palestinian regions. Rat blood meals might be significant since a few strains L. tropica and L. infantum

Effectiveness of insecticide thermal fogging in hyrax dens in the control of leishmaniasis vectors in rural Palestine: A prospective study

“…L. tropica was the most frequently carried by P. sergenti. The proportion of P. sergenti that was infected with L. tropica in the pre-intervention phase in PLOS NEGLECTED TROPICAL DISEASES the intervention site was higher than that reported in previous studies: 4.1% (N = 145) in residential areas and hyrax dens in West Bank [11] and 1.2% (N = 162) in the Galilee region (Al-Jaleel), about 70 km north of Tubas [8]. In Morocco, the proportion was 3.2% (n = 216) and 3.7% (n = 273) [43,44].…”

“…tropica infection within P . sergenti was 61% (number of tested sand flies (N) = 31) in Tubas district, 4.1% (N = 145) in Jenin District, and 1.2% (N = 162) in the Galilee region (Al-Jaleel), about 70 km north of Tubas [ 8 , 10 , 11 ].…”

“…In the last two decades, hyrax colonies in the periphery of Tayasir, Tubas district, increased markedly due to the availability of natural and artificial places that serve as their dens. Adult sand flies are present only in summer with peak activity from July to September [ 11 , 27 ]. Between 1990–2019, 108 CL cases (average: 6/year) with a cumulative incidence of 58/1000 (13.2% of all cases in the district) were reported in Tayasir mainly from residencies in the village periphery.…”

“…However, in recent years, proliferation of rock-piles and other artificial shelters for hyraxes close to residential areas has resulted in their relocation here, creating new breeding sites for P. sergenti [9]. Previous studies in Palestine indicated that L. tropica infection within P. sergenti was 61% (number of tested sand flies (N) = 31) in Tubas district, 4.1% (N = 145) in Jenin District, and 1.2% (N = 162) in the Galilee region (Al-Jaleel), about 70 km north of Tubas [8,10,11].…”