Laboratory evaluation of diflubenzuron as a feed-through for control of immature sand flies (Diptera: Psychodidae)

The benzoylurea chitin synthesis inhibitor diflubenzuron was evaluated as a rodent feed-through for the control of immature stages of Phlebotomus papatasi Scopoli (Diptera: Psychodidae). The development and survival of second instars of P. papatasi larvae that were fed feces from Syrian hamsters, Mesocricetus auratus, that had been fed a diet containing 0, 8.97, 89.7, or 897 ppm diflubenzuron was evaluated. No pupation or adult emergence occurred when larvae were fed feces from hamsters that were fed diets containing diflubenzuron. The mortality of sand flies fed feces from treated hamsters was coincident with pupation of the controls, suggesting a specific effect on the larval-to-pupal molt. The results of this study suggest that a control strategy using rodent baits containing diflubenzuron for phlebotomine sand flies and zoonotic cutaneous leishmaniasis may be possible.     

Wolbachia infections of phlebotomine sand flies (Diptera: Psychodidae)

Old and New World phlebotomine sand fly species were screened for infection with Wolbachia, intracellular bacterial endosymbionts found in many arthropods and filarial nematodes. Of 53 samples representing 15 species, nine samples offour species were found positive for Wolbachia by polymerase chain reaction amplification using primers for the Wolbachia surface protein (wsp) gene. Five of the wsp gene fragments from four species were cloned, sequenced, and used for phylogenetic analysis. These wsp sequences were placed in three different clades within the arthropod associated Wolbachia (groups A and B), suggesting that Wolbacia has infected sand flies on more than one occasion. Two distantly related sand fly species, Lutzomyia (Psanthyromyia) shannoi (Dyar) and Lutzomyia (Nyssomyia) whitmani (Antunes & Coutinho), infected with an identical Wolbachia strain suggest a very recent horizontal transmission.     

Laboratory evaluation of rubidium as a long-lasting marker for bloodfeeding sand flies (Diptera: Psychodidae)

The objective of this study was to evaluate the use of the trace element rubidium (Rb) as a long-lasting systemic biomarker for bloodfeeding females of the sand fly Phlebotomus papatasi Scopoli. Baits containing Rb chloride were found to be palatable to hamsters in this study. We were able to detect Rb using a portable X-ray fluorescence analyzer in all sand flies that fed on Rb-treated hamsters for at least 14 d postbloodmeal. We also detected Rb in sand flies that took a bloodmeal from hamsters up to 10 d after the hamsters were withdrawn from a Rb-treated diet. Results of this study constitute proof of concept for the incorporation of Rb chloride into rodent baits for marking bloodfeeding sand flies, and suggest that Rb marking could be used as a technique for evaluating rodent-targeted sand fly control methods and in ecological studies on sand flies.     

Sensilla on the terminalia of Lutzomyia spp. (Diptera: Psychodidae) sand flies

Sensilla on the male terminalia of four different species of sand flies (Diptera: Psychodidae) are described. Two species belonged to the same species complex: Lutzomyia longipalpis (Lutz & Neiva) and L. cruzi (Mangabeira). Other Brazilian species complex was represented by L. lenti (Mangabeira) and L. carmelinoi (Ryan, Fraiha, Lainson & Shaw). Approximately 5-15 sensilla were found on the initial part of the styles of all species. Structurally, the sensory organs were similar to small coeloconica sensilla. Their number varied both individually and interspecifically. These sensilla may play an important role in the copulation behavior of these species of sand flies.     

First collection records of phlebotomine sand flies (Diptera: Psychodidae) from New Jersey

The phlebotomine sand flies Lutzomyia (Psathyromyia) shannoni (Dyar) and Lutzomyia (Helcocyrtomyia) vexator (Coquillett) are reported for the first time from New Jersey. Both species were collected from ultraviolet CO2-baited Centers for Disease Control light traps during a state-wide phlebotomine survey conducted in 2007 and 2008. L. shannoni has previously been reported from New Jersey; however, this observation was made in error. These collections do not represent a northern range expansion for either species.     

Funnel trap for the capture of phlebotomine sand flies (Diptera: Psychodidae) from tree holes

A funnel trap that fitted over holes leading into hollow trees was used to capture adult phlebotomine sand flies, Lutzomyia shannoni Dyar, on Ossabaw Island, Chatham County, Ga. These insects rested in hollow trees during the day and were collected by funnel traps as they egressed from the tree holes at night. The trap is lightweight, durable, inexpensive, waterproof, and selective. Using this trap, greater than 100 healthy L. shannoni ++were captured per night by a single investigator during July and August 1988 when adult flies were abundant on the island.     

Genetic relationships among phlebotomine sand flies (Diptera: Psychodidae) in the verrucarum species group

Isozyme data were used to identify populations of certain Lutzomyia taxa in the verrucarum species group, mostly in the series townsendi. Lutzomyia youngi Feliciangelis and Murillo and L. spinicrassa Morales, Osorno, Osorno, and Hoyos each have diagnostic allomorphs for phosphogluconate dehydrogenase (6PGDH) and fumarate hydratase (FUM). The 6PGDH and FUM data and those from 6-phospho-fructokinase and phosphoglucomutase distinguish Lutzomyia sp., a new species from Columbia to be described and named later. Data from these enzymes and glucose phosphate isomerase will separate L. townsendi (Ortiz) from the others and from L. longiflocosa Osorno, Morales, Osorno, and Hoyos, L. quasitownsendi Morales, Osorno, Osorno, and Hoyos, and L. sauroida Osorno, Morales, and Osorno (three species that are inseparable using enzyme data). Three other species, L. serrana (Damasceno and Arouck) (series serrana) and L. columbiana (Ristorcelli and Van Ty) and L. andina Osorno, Osorno, and Morales (both in series verrucarum), are morphologically distinct using conventional characters and have fixed diagnostic differences at several enzyme loci. Statistical analyses of the enzyme data using genetic identities (I), differences (D), and the amount of genetic variation among these taxa indicated that such statistics can be as useful in the study of sand fly phylogeny and population genetics as they have been for other organisms. I and D values indicated that L. longiflocosa, L. quasitownsendi, and L. sauroida are very similar (I = 0.991 and D = 0.010) and possibly are populations of the same conspecific species. The levels of divergence, based on combined enzyme data for up to 21 gene loci among the taxa, are discussed, and a dendrogram based on genetic distance is presented. The genetic data confirmed established phylogenetic relationships among the sand fly taxa based on structural similarities.     

Efficacy of commercial mosquito traps in capturing phlebotomine sand flies (Diptera: Psychodidae) in Egypt

Four types of commercial mosquito control traps, the Mosquito Magnet Pro (MMP), the Sentinel 360 (S360), the BG-Sentinel (BGS), and the Mega-Catch Ultra (MCU), were compared with a standard Centers for Disease Control and Prevention (CDC) light trap for efficacy in collecting phlebotomine sand flies (Diptera: Psychodidae) in a small farming village in the Nile River Valley 10 km north of Aswan, Egypt. Each trap was baited with either carbon dioxide (CO2) from combustion of butane gas (MMP), dry ice (CDC and BGS traps), light (MCU and S360), or dry ice and light (CDC). Traps were rotated through five sites in a5 x 5 Latin square design, repeated four times during the height of the sand fly season (June, August, and September 2007) at a site where 94% of sand flies in past collections were Phlebotomus papatasi (Scopoli). A total of 6,440 sand flies was collected, of which 6,037 (93.7%) were P. papatasi. Of the CO2-baited traps, the BGS trap collected twice as many P. papatasi as the MMP and CDC light traps, and at least three times more P. papatasi than the light-only MCU and S360 traps (P < 0.05). Mean numbers (+/- SE) of P. papatasi captured per trap night were as follows: BGS 142.1 (+/- 45.8) > MMP 56.8 (+/- 9.0) > CDC 52.3 (+/- 6.1) > MCU 38.2 (+/- 6.4) > S360 12.6 (+/- 1.8). Results indicate that several types of commercial traps are suitable substitutes for the CDC light trap in sand fly surveillance programs.     

Variation of esterase electromorphs associated with bloodmeal digestion in phlebotomine sand flies (Diptera: Psychodidae)

Esterases are often used to measure genetic variation, yet they may be influenced by external factors. Isoelectrofocusing was used to investigate the effects of bloodmeal on the esterase variation in wild populations of Phlebotomus (Larroussius) ariasi Tonnoir and P. (L.) perniciosus Newstead and in a colonized population of P. (Phlebotomus) duboscqi Neveu-Lemaire. Modified electrophoretic profiles were demonstrated to be associated with blood digestion. The bloodmeal-induced esterase electromorphs were only found in the abdomen homogenates of the sand flies. These changes in esterase phenotype were probably due to a proteolysis phenomenon and disappeared at the end of bloodmeal digestion. The effect was eliminated by adding trypsin inhibitors.     

Laboratory evaluation of novaluron as a development site treatment for controlling larval horn flies, house flies, and stable flies (Diptera: Muscidae)

A granular formulation of novaluron (Novaluron 0.2G, 0.2% [AI]), a newer benzoylphenyl urea insecticide, was evaluated for its efficacy in controlling the larval stage of horn flies, Haematobia irritans (L.); house flies, Musca domestica L.; and stable flies, Stomoxys calcitrans (L.), in cow manure. Various rates and insecticide placement locations (top, middle, and bottom of manure) were evaluated in this study and all combinations of these variables reduced adult emergence of all three species when compared with the untreated controls. The presence of deformed pupae indicated that novaluron had an insect growth regulator effect on the developing fly larvae. Top, middle, or bottom application rates of 0.125, 0.195, 0.25, and 0.375 g novaluron onto manure samples, reduced adult horn fly emergence by > 90%. Middle and bottom application rates of 0.195, 0.25, and 0.375 g novaluron reduced adult house fly emergence >93%. All rates and placement combinations resulted in >98% reduction of adult stable fly emergence. The level of control efficacy observed against these three fly species along with the ease of use of a granular formulation, make this product an ideal candidate for use in an integrated livestock pest management program.     

Phlebotomine sand flies (Diptera: Psychodidae) of the Palestinian West Bank: potential vectors of leishmaniasis

Two forms of leishmaniasis are endemic to the Jenin district in the northern region of the West Bank. Visceral leishmaniasis (VL), caused by Leishmania infantum, mainly affects infants. Cutaneous leishmaniasis (CL) affects a broader age group and is probably caused by L. tropica. Although the Jenin district is the most important focus of leishmaniasis in the West Bank, the sand fly fauna of the area has never been studied in a systematic manner. We collected base-line data on sand fly species, their distribution, and their feeding preferences to facilitate risk assessments for contracting leishmaniasis. Light traps, sticky traps, insecticide knockdown collections, aspirator, and human-landing collections were used. A total of 4,082 sand flies was collected in foci of confidence limits and/or VL between June and December 1998. Nine Phlebotomus species representing seven subgenera were identified: P. (Larroussius) perfiliewi transcaucasicus Perfil'ev, P. (La.) tobbi Adler & Theodor, P. (La.) mascitti canaaniticus Adler & Theodor, P. (La.) mascitti mascitti Grassi, P. (La.) syriacus Adler & Theodor, P. (Phlebotomus) papatasi Scopoli, P. (Synphlebotomus) s.p., P. (Paraphlebotomus) sergenti Parrot, P. (Par.) jacusieli Theodor, P. (Adlerius) halepensis Theodor. Two other Phlebotomus subspecies, P. (La.) major major Annandale, P. (La .) neglectus Tonnoir, require confirmation. In addition, four species of the closely related genus, Sergentomyia were also found: S. (Sergentomyia) theodori Parrot, S. (S.) fallax Parrot, S. (Sintonitus) tiberiadis Adler, Theodor & Lourie, S. (Sin.) christophersi Sinton. Among five species of sand flies collected on human bait, P. papatasi constituted approximately 90% followed by P. major syriacus (8%) and P. mascitti (2%). Sand fly human-biting activity occurred through the night and it was highest between 2400 and 0300 hours. P. papatasi. P. perfiliewi, P. major and P. tobbi were the more endophilic species constituting 93% of all flies caught indoors. Seven Phlebotomus spp. constitute potential vectors of leishmaniasis but the most probable ones are as follows: P. papatasi the main human-biting species, a recognized vector of L. major (CL), P. sergenti, L. tropica (CL) and P. syriacus, L. infantum (VL).     

Distribution of phlebotomine sand flies (Diptera: Psychodidae) in a primary forest-crop interface, Salta, Argentina

Disordered urbanization and deforestation are the main activities proposed as causal factors of re-emergence of American cutaneous leishmaniasis caused by Leishmania braziliensis. The purpose of this work was to investigate, in the hyperendemic area of Argentina, the distribution of Phlebotomine sand flies at the modified primary vegetation-crop interface, as one of the potential sites where the effects of changing landscape on sand fly populations may be manifested. Twenty samplings were made between June 2004 and August 2005. The traps to catch sand flies were set on two consecutive nights every month (except in 5 mo, where it became every 15 d). The relationship between sand fly abundance and meteorological and landscape variables was analyzed using non-metric multidimensional scaling and Kendall's correlation coefficients. Lutzomyia neivai (Pinto) was the most abundant species, followed by Lutzomyia migonei (Fran?a), Lutzomyia cortelezzii (Brèthes), Lutzomyia shannoni (Dyar), and Lutzomyia punctigeniculata (Floch and Abonnenc). Traps located close to modified areas collected the greatest numbers of sand flies, whereas traps located in the least modified area (adjacent to the primary vegetation) collected the fewest. There was a strong negative correlation between the abundance of sand flies and precipitation. This study shows that even small modifications in the landscape led to an increase in sand fly abundance, mainly Lu. neivai, a Leishmania braziliensis vector. This underscores the need for recommendations about the risk of American cutaneous leishmaniasis before any environmental intervention is done in an endemic area, as well as for the monitoring of sand fly population dynamics at the site of intervention, before, during, and after the process.     

Diversity of phlebotomine sand flies (Diptera: Psychodidae) in Ibitipoca State Park, Minas Gerais, Brazil

Leishmaniasis is a complex of zoonotic diseases that are endemic to many Brazilian states. They are transmitted to the vertebrates by the bite of the hematophagous female sand fly (Diptera: Psychodidae) vectors. Despite the increasing occurrence of visceral and cutaneous leishmaniasis cases in large urban centers, their transmission continues to occur primarily in a wild environment and may be associated with professional activities, ecotourism activities, or both. This study investigates the ecological parameters of the sand flies present in Ibitipoca State Park, Minas Gerais, Brazil. During 2009, systematic collections of sand flies were made monthly using HP light traps installed at five sites, including three natural settings (a cave, riparian vegetation, and a rain forest), the tourist and researchers' accommodations, and a surrounding domestic livestock area. In total, 161 sand flies (seven species) were collected, the most abundant, particularly in the surrounding domestic livestock area, being Lutzomyia (Psychodopygus) lloydi (Antunes, 1937). Furthermore, a previously unidentified Lutzomyia (Sciopemyia) sp. was prevalent in the cave environment. There are no existing records of the occurrence of leishmaniasis in Ibitipoca State Park; however, the some species of the subgenus Psychodopygus are known vectors of Leishmania spp in Brazil. Hence, the presence of a species of this genus in areas surrounding the park may represent a risk to ecotourism and the local inhabitants. Our study shows the importance of regular monitoring of the various areas used by humans to determine the distribution and spread of sand fly vectors for preventive management to forestall potential risk to health and consequent effect on ecotourists.