Mitochondrial and Wolbachia markers for the sandfly Phlebotomus papatasi: little population differentiation between peridomestic sites and gerbil burrows in Isfahan province, Iran

In Iran, Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) is the main vector of Leishmania major Yakimoff & Schokhor (Kinetoplastida: Trypanosomatidae), the causative agent of rural zoonotic cutaneous leishmaniasis. This sandfly is abundant both in villages and in the burrows of the main reservoir host, the gerbil Rhombomys opimus (Licht.) (Rodentia: Gerbillidae). Populations of P. papatasi were sampled from the edges of villages in Isfahan province, using CDC miniature light traps in peridomestic sites and sticky papers placed at the entrances to gerbil burrows. Single peridomestic sites in two northern provinces were also sampled. Individual sandflies were characterized by PCR amplification and sequencing of fragments of their mitochondrial cytochrome b gene and of the wsp gene of endosymbiotic Wolbachia pipientis Hertig (alpha-Proteobacteria: Rickettsiaceae). The distributions of the haplotypes of these two maternally inherited genes were analysed to assess the population differentiation of P. papatasi, knowledge of which will be needed for planning control measures. For the first time these markers were used to characterize P. papatasi from gerbil burrows, and they indicated the absence not only of sympatric cryptic species but also of any long-term differentiation of lineages in different habitats. A single lineage of cytochrome b haplotypes was found, and both sexes in all populations had a high infection rate of the same A-group strain of Wolbachia (wPap). The distributions of cytochrome b haplotypes were consistent with females dispersing more than males, which has been reported for P. papatasi in other countries. The widespread distribution of wPap suggests that Wolbachia could be used to spread transgenes between populations of P. papatasi in different habitats.     

Bionomics of phlebotomine sandflies in the Galilee focus of cutaneous leishmaniasis in northern Israel

The bionomics of phlebotomine sandflies (Diptera: Psychodidae) were studied for three years (2001-2003) in the Galilee focus of cutaneous leishmaniasis in northern Israel, where the causative Leishmania tropica (Kinetoplastida: Trypanosomatidae) is transmitted by Phlebotomus (Adlerius) arabicus Theodor and Phlebotomus (Paraphlebotomus) sergenti Parrot, comprising 22% and 8%, respectively, of the local sandfly fauna sampled by light traps. The predominant species overall was Phlebotomus (Larroussius) tobbi Adler & Theodor (51%) with lesser numbers of Phlebotomus (Adlerius) simici Theodor (11%), Phlebotomus (Larroussius) syriacus Adler & Theodor (5%), Phlebotomus (Larroussius) perfiliewi Perfil'ev (3%) and Phlebotomus (Phlebotomus) papatasi Scopoli (0.05%). Sandfly adult populations were prevalent from April to November and peaked between June and August, being more abundant through the summer in irrigated habitats, such as gardens and orchards, than in open grassland. Of the two cutaneous leishmaniasis vectors, P. sergenti preferred boulder mounds located at the outskirts of settlements, whereas P. arabicus was more abundant overall and near houses in particular. Females of all these sandfly species displayed a peak of activity after sunset (20.00-22.00 hours), whereas activity of males persisted longer through the night. Another slight increase in activity was noted before dawn (02.00-04.00 hours). Phlebotomus arabicus appears to be the main vector of L. tropica in the Galilee focus, due to its denser populations, more endophily and preference for peridomestic habitats than shown by P. sergenti in northern Israel.     

Sugars in the gut of the sandfly Phlebotomus orientalis from Dinder National Park, Eastern Sudan

The sandfly Phlebotomus orientalis Parrot (Diptera: Psychodidae) is the vector of visceral leishmaniasis in eastern and Upper Nile regions of Sudan, where vector infection rates of over 7% have been reported. Sugars are known to be important for development of the parasite and for increasing the survival and oviposition rates of several species of sandflies. In the present study we have analysed the sugars present in the guts of individuals and groups of male and female P. orientalis and compared these with sugars from several potential local plant sources: Acacia seyal, Balanites aegyptiaca and Combretum kordofanum. The distribution of these trees in Sudan is closely correlated with that of P. orientalis. Only 20% of individually analysed female sandflies had significant amounts of sugars present suggesting that P. orientalis either digest their sugar meal quickly or do not require regular sugar meals. Interestingly, the sugars present in the males were significantly different to those found in the females, indicating that they had fed on different sugar sources. There was evidence that fruit sugars from Balanites aegyptiaca, Combretum kordofanum and aphid or coccid honeydew are utilized by male and female P. orientalis. There was evidence to indicate that female P. orientalis feeds directly on honeydew. There was no evidence to indicate that direct feeding on leaves is a typical source for the sugar meal. There was no melizitose and only a very small amount of turanose present in the male, suggesting that honeydew was not an important sugar source for males.     

Sand fly species of Sanliurfa province in Turkey

The species composition and seasonal abundance of sand flies (Diptera: Phlebotominae) were studied in the years 2000-2002 in the Sanliurfa region, which is the largest focus of cutaneous leishmaniasis in south-eastern Turkey. Sixteen species were identified among 29 771 specimens collected at 17 different sites by light traps, sticky papers and aspirators. The most common species were Phlebotomus papatasi (Scopoli) (45.4%), P. perfiliewi Parrot (21.9%), and P. sergenti Parrot (19.4%). The other species found were P. major Adler & Theodor (3%), P. neglectus Leger & Pesson (2.2%), P. brevis Theodor & Mesghali (2%), P. alexandri Sinton (1.9%), P. galilaeus Theodor (1.6%), P. halepensis Theodor (0.84%), Sergentomyia adleri Theodor (0.78%), S. dentata Sinton (0.49%), S. minuta Rondani (0.42%), S. theodori Parrot (0.16%), P. kazeruni Theodor & Mesghali (0.001%) and P. mascitti Grassi (0.001%) and one unidentified Phlebotomus species. Among these species P. galilaeus, S. minuta and S. dentata are the first records for this area. All species showed seasonal fluctuations, with the period of highest abundance between May and October.     

Leishmaniasis in the Jordan Valley. V. Dispersal characteristics of the sandfly Phlebotomus papatasi

Several characteristics of dispersing and non-dispersing Phlebotomus papatasi (Scopoli) were quantified and compared. The majority of dispersing sandflies, trapped crossing fallow fields, were females (68.5% v. 51.1%); of the dispersing females, 55.4% were parous, 48.1% were inseminated and 11.6% were gravid. In the population of sandflies sampled exiting from burrows of the sand rat Psammomys obesus Cretschmar, these categories, respectively, represented 39%, 90% and 26% of the females examined. Leishmania promastigotes were found in 9% of females exiting from P. obesus burrows, and in 2.7% of the dispersing females. The anthrone test established that the reason for activity of gravid females is sugar feeding. These females do not disperse and are suitable targets for future control measures.     

Comparative field study to evaluate the performance of three different traps for collecting sand flies in northeastern Italy

Three standard methods for collecting sand flies (sticky trap, CDC light trap, and CO₂ trap) were compared in a field study conducted from June to October, 2012, at a site located in the center of a newly established autochthonous focus of canine leishmaniasis in northeastern Italy. Six traps (two sticky traps, two CDC light traps, and two CO₂ traps) were activated at the same time for a single night every two weeks during the season of sand fly activity. A total of 5,667 sand flies were collected and 2,213 identified, of which 82.1% were Phlebotomus perniciosus, 17.4% P. neglectus, 0.3% Sergentomya minuta, and 0.2% P. mascitti. The performances of all traps were influenced by their position inside the site, increasing with proximity to the animal shelters. CO₂ traps were more attractive for females of P. perniciosus and P. neglectus. CDC light traps showed an intermediate efficiency and were more attractive for P. neglectus, compared to other two traps. Results suggest that in northern Italy the CO₂ trap is a suitable sampling method for sand fly monitoring programs that include transmitted pathogen surveillance.     

The recombinant protein rSP03B is a valid antigen for screening dog exposure to Phlebotomus perniciosus across foci of canine leishmaniasis

The frequency of sandfly–host contacts can be measured by host antibody levels against sandfly salivary proteins. Recombinant salivary proteins are suggested to represent a valid replacement for salivary gland homogenate (SGH); however, it is necessary to prove that such antigens are recognized by antibodies against various populations of the same species. Phlebotomus perniciosus (Diptera: Psychodidae) is the main vector of Leishmania infantum (Trypanosomatida: Trypanosomatidae) in southwest Europe and is widespread from Portugal to Italy. In this study, sera were sampled from naturally exposed dogs from distant regions, including Campania (southern Italy), Umbria (central Italy) and the metropolitan Lisbon region (Portugal), where P. perniciosus is the unique or principal vector species. Sera were screened for anti‐P. perniciosus antibodies using SGH and 43‐kDa yellow‐related recombinant protein (rSP03B). A robust correlation between antibodies recognizing SGH and rSP03B was detected in all regions, suggesting substantial antigenic cross‐reactivity among different P. perniciosus populations. No significant differences in this relationship were detected between regions. Moreover, rSP03B and the native yellow‐related protein were shown to share similar antigenic epitopes, as canine immunoglobulin G (IgG) binding to the native protein was inhibited by pre‐incubation with the recombinant form. These findings suggest that rSP03B should be regarded as a universal marker of sandfly exposure throughout the geographical distribution of P. perniciosus.     

Evidence for an impact on the incidence of canine leishmaniasis by the mass use of deltamethrin-impregnated dog collars in southern Italy

Dogs are the domestic reservoir of Leishmania infantum Nicolle (Kinetoplastida: Trypanosomatidae), the agent of zoonotic human visceral leishmaniasis. In southern Europe, where canine leishmaniasis (CanL) is widespread due to L. infantum, killing seropositive dogs is considered unacceptable and drug treatment has low efficacy in preventing transmission. We made a field evaluation of the efficacy of deltamethrin dog collars in a CanL focus of southern Italy, Mount Vesuvius area of Campania region, where the vector is Phlebotomus perniciosus Newstead (Diptera: Psychodidae), by assessing their impact on the incidence of CanL in an intervention town, compared to that in dogs of control towns where no collars were fitted. During two consecutive transmission seasons, collars were fitted to 350 (1998) and 354 (1999) dogs from San Sebastiano al Vesuvio (70% of the canine population). Control dogs (371 and 264 in the 2 years, respectively) were from four towns of the same area. Before each transmission season, the CanL seroprevalence in the intervention and control towns was evaluated by cross-sectional surveys and found to be similar (about 15% in 1998 and 10% in 1999, respectively). After each transmission period, incidence rates of seroconversions were determined in adult dogs that were serologically negative before the season under evaluation, and in puppies. After the 1998 season, 2.7% of the dogs in the intervention town seroconverted compared to 5.4% in the control towns (50% protection, P = 0.15). After the 1999 season, 3.5% of collared dogs seroconverted compared to 25.8% of control dogs (86% protection, P < 0.001). The increase in seroconversion rates recorded in control dogs suggests an increase in the Leishmania force of infection in the canine reservoir during the 1999 sandfly season, as supported by the concomitant increase of human cases in control towns and in the whole Campania region. Our results suggest that the impact of mass use of deltamethrin-impregnated dog collars on the incidence of CanL may be negligible during low transmission seasons, or probably in low endemic foci, but can be very strong when the force of transmission is high.     

Distribution of phlebotomine sandflies, of the subgenus Larroussius, in Morocco

Adult sandflies (Diptera: Psychodidae) of the genus Phlebotomus and of the subgenus Larroussius were collected with sticky traps from thirty-four localities in central and south-western Morocco. Four Larroussius species were present in this area, Phlebotomus perniciosus Newstead, being the most widespread and abundant species particularly in the mountainous area, was sympatric with the closely related species Phlebotomus longicuspis Nitzulescu. Only one male of P. perniciosus displayed the bifid copulatory valves characteristic of the species. All specimens showed copulatory valves curved at their apex. The number of coxite hairs is a taxonomical tool that differentiates this morph of P. perniciosus from P. longicuspis. Phlebotomus ariasi Tonnoir was collected from six mountainous stations. Phlebotomus mariae Rioux et al. was scarce; only five males were collected and were often associated with P. ariasi.