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.     

Aspects of the bionomics of Phlebotomus sergenti sandflies from an endemic area of anthroponotic cutaneous leishmaniasis in Aleppo Governorate, Syria

Aspects of the bionomics of phlebotomine sandflies (Diptera: Psychodidae) were studied from June to November 2005 in three foci of anthroponotic cutaneous leishmaniasis (ACL) in Aleppo Governorate, Syria, where the agent Leishmania tropica (Wright) (Kinetoplastida: Trypanosomatidae) is transmitted by Phlebotomus sergenti Parrot. Syria has been designated by the World Health Organization as one of four countries in the Old World where cutaneous leishmaniasis is hyperendemic, but little is known about the biology of local vector populations. Standard collections by sticky traps showed two peaks in density, in June and late August. In total, 1840 sandflies were caught, comprising five species: Phlebotomus papatasi (Scopoli) (68.0%); P. sergenti (25.4%); Sergentomyia minuta (Rondani) (6.4%); Phlebotomus tobbi Adler & Theodor (0.1%), and Phlebotomus mascittii canaaniticus Adler & Theodor (0.1%). Similar numbers of P. sergenti were caught indoors (246 specimens) and outdoors (222), whereas P. papatasi was significantly more abundant indoors (1096 specimens) than outdoors (156) (χ² = 241, P < 0.01). In total, 212 blood-fed females were tested for host blood determination, of which 176 (83.0%) reacted with anti-species reagent. Results from 20 P. sergenti suggest that this species is an opportunistic feeder, imbibing human, ovine, avian, bovine and feline blood, although more bloodmeals were taken from humans and cattle than expected in relation to the relative proportions of potential hosts present (the forage ratio, FR). The bionomics of P. sergenti are discussed in relation to the inefficacy of control campaigns based on indoor spraying with residual insecticides that have been implemented by the Syrian Ministry of Health to control the epidemics of ACL in the Aleppo Governorate.     

About the presence of Phlebotomus sergenti Parrot, 1917 (Diptera: Psychodidae) in Eastern Sicily, Italy

The note reports the data of a three-year sand fly investigation (1997-99) carried out in Eastern Sicily (Italy) with the aim to study the distribution of Phlebotomus sergenti. The survey involved a densely inhabited area at the foot of Mount Etna and the area of Iblei mounts. A total of 9,095 sand flies, of which 63.4% males, were captured. Five species belonging to the genus Phlebotomus (P. perniciosus, P. perfiliewi, P. neglectus, P. sergenti and P. papatasi) and one to the genus Sergentomyia (S. minuta) were identified. Both the prevalence and distribution of the species were different within the two areas studied. In Mount Etna area, P. perniciosus (77.7%) was the prevalent species followed by S. minuta (19.8%), P. sergenti (2.0%), P. neglectus (0.3%) and P. papatasi (0.2%). While in Iblei mounts region S. minuta (84.5%) showed the highest prevalence, followed by P. perniciosus (14.4%), P. perfiliewi (0.9%) and P. neglectus (0.1%). Here, P. sergenti was a very rare species (< 0.02). P. sergenti was mostly associated to domestic habitats of peri-urban and urban zones located between two and 750 m a.s.l. The density values of P. sergenti, expressed as number of specimens/m2 of sticky trap, were between 0.3 and 5.5 with the highest value in the hilly collecting sites. The low observed abundance of P. sergenti does not allow to draw any prediction on the role that the species could play in the transmission of leishmaniasis in Sicily.     

Phlebotomines of the Isle of Cyprus. III. Species inventory

Three surveys on canine leishmaniasis were carried out in Cyprus (1993, 1998 and 1999) emphasise the presence of eleven species of phlebotomine sandflies: Phlebotomus (Phlebotomus) papatasi, P. (Paraphlebotomus) alexandri, P. (Pa.) jacusieli (first mention in Cyprus), P. (Pa.) sergenti, P. (Larroussius) galilaeus, P. (L.) tobbi, P. (Transphlebotomus) economidesi, P. (T.) mascittii, Sergentomyia (Sergentomyia) azizi (its specific statute is validated by the authors), S. (S.) fallax et S. (S.) minuta. P. (Adlerius) kyreniae was not caught during the surveys. The authors propose hypothesis of settlement of the island by phlebotomine sandflies according this species inventory. A first migration period took probably place during the Miocene time and a second one during the Pleistocene time.     

Distribution and altitudinal structuring of phlebotomine sand flies (Diptera: Psychodidae) in southern Anatolia, Turkey: their relation to human cutaneous leishmaniasis.

The two Old World genera, Phlebotomus and Sergentomyia, were both recorded in southern Anatolia in Turkey. Phlebotomus species predominated and comprised about 93% of the entire collection (3,172 specimens). Out of the sixteen species identified, two belonged to the genus Sergentomyia: S. dentata and S. theodori. The remaining fourteen species in the genus Phlebotomus were grouped under four subgenera including some species that are elsewhere known to act as vectors of human cutaneous leishmaniasis. Most of the Phlebotomus were P. tobbi (32.5%), but P. papatasi, P. transcaucasicus, P. halepensis, P. galilaeus, P. sergenti, P. syriacus, P. neglectus, P. simici, P. alexandri, P. similis, P jacusieli, P. perfiliewi, and P. brevis were also identified. There were two associations of sand fly fauna with altitudinal gradient; the first one at relatively higher altitudes and the second one at lower altitudes. The transition between these two assemblages was within the range of 800-1,000 m. It is likely that Adana and Hatay provinces are transitional areas between western and eastern Anatolia. Mountains do not appear to be important geographical barriers for sand fly distribution. We also found that the proven vector P. sergenti is a widely distributed species throughout southern Anatolia and this species, together with its closely related species P. similis, shows sympatry in Konya Province.     

Limits of a rapid identification of common Mediterranean sandflies using polymerase chain reaction-restriction fragment length polymorphism

A total of 131 phlebotomine Algerian sandflies have been processed in the present study. They belong to the species Phlebotomus bergeroti, Phlebotomus alexandri, Phlebotomus sergenti, Phlebotomus chabaudi, Phlebotomus riouxi, Phlebotomus perniciosus, Phlebotomus longicuspis, Phlebotomus perfiliewi, Phlebotomus ariasi, Phlebotomus chadlii, Sergentomyia fallax, Sergentomyia minuta, Sergentomyia antennata, Sergentomyia schwetzi, Sergentomyia clydei, Sergentomyia christophersi and Grassomyia dreyfussi. They have been characterised by sequencing of a part of the cytochrome b (cyt b), t RNA serine and NADH1 on the one hand and of the cytochrome C oxidase I of the mitochondrial DNA (mtDNA) on the other hand. Our study highlights two sympatric populations within P. sergenti in the area of its type-locality and new haplotypes of P. perniciosus and P. longicuspis without recording the specimens called lcx previously found in North Africa. We tried to use a polymerase chain reaction-restriction fragment length polymorphism method based on a combined double digestion of each marker. These method is not interesting to identify sandflies all over the Mediterranean Basin.     

Phlebotomine sandflies (Diptera-Psychodidae) of the isle of Cyprus. II--Isolation and typing of Leishmania (Leishmania infantum Nicolle, 1908 (zymodeme MON 1) from Phlebotomus (Larroussius) tobbi Adler and Theodor, 1930

During two surveys conducted in Cyprus (August 1998 and September 1999), 2,910 phlebotomine sandflies females were caught by CDC miniature light traps then dissected under binocular and examined on microscope. Eleven species were identified: Phlebotomus papatasi, P. sergenti, P. jacusieli, P. alexandri, P. tobbi, P. galilaeus, P. mascittii, P. economidesi, Sergentomyia fallax, S. minuta et S. azizi. The Larroussius species (P. galilaeus and P. tobbi) are the most abundant (more than 60% of our captures). Promastigotes were isolated from one specimen identified as P. tobbi. A Leishmania stock was successfully cultured and identified by isoenzyme characterisation as belonging to L. infantum zymodeme MON 1. The same zymodeme was isolated and identified from four dogs too. Because of the absence of usual vectors of L. infantum in the eastern part of the Mediterranean basin (P. neglectus and P. syriacus), and according to its distribution in Cyprus, P. tobbi constitute certainly a good local vector. It seems to be not very anthropophilic, that could explain the very few human cases.     

Associations of Phlebotomus orientalis and other sandflies with vegetation types in the eastern Sudan focus of kala-azar

Abundances of Phlebotomus orientalis, P. papatasi (Diptera: Psychodidae) and other sandflies were investigated in relation to different types of vegetation associated with endemic foci of visceral leishmaniasis (kala-azar) in eastern Sudan. Sandfly collection sites were in Umsalala Village (Galabat Province) and Dinder National Park (Dinder Province). Sandfly species found in the area were P. orientalis, P. papatasi, Sergentomyia africana, S. antennata, S. clydei, S. schwetzi and S. squamipleuris. Among the types of trees in the Dinder area, P. orientalis was more abundant in forests dominated by Acacia seyal than where Combretum kordofanum, Balanites aegyptiaca, Hyphaena thaibaica or Ziziphus spinachristi were the dominant trees. At Umsalala, P. papatasi was more abundant in the village than at any site with dense vegetation, but P. orientalis was uncommon. Sergentomyia spp. were distributed fairly evenly amongst most types of vegetation investigated at both localities. The ecological distribution of sandflies and epidemiology of kala-azar in Sudan are discussed with emphasis on the association of P. orientalis with A. seyal woodlands.     

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.     

Sandflies (Diptera: Psychodidae) in a focus of visceral leishmaniasis in White Nile, Sudan

Visceral leishmaniasis (VL) has been known to occur since the 1980s on the western bank of the White Nile River (Central Sudan), 150 km south of Khartoum, and has resulted in high mortality. The most recent outbreak of the disease in this area began in 2006. Entomological surveys were carried out during May 2008, June 2010 and May and July 2011 in the White Nile area. Sandflies were collected using Centers for Disease Control light traps and sticky oil traps in the village of Kadaba and the nearby woodland. Phlebotomus females were dissected for the presence of Leishmania promastigotes. A total of 17,387 sandflies, including six species of Phlebotomus and 10 species of Sergentomyia, were identified. The Phlebotomus species recorded were Phlebotomus orientalis, Phlebotomus papatasi, Phlebotomus bergeroti, Phlebotomus duboscqi, Phlebotomus rodhaini and Phlebotomus saevus. P. orientalis was collected in both habitats. The relative abundance of P. orientalis in the woodland habitat was higher than that recorded in the village habitat. In the woodland habitat, there was a notable increase in the relative abundance of P. orientalis during the surveys conducted in 2008 and 2010 compared to 2011. None of the 311 P. orientalis females dissected were infected with Leishmania promastigotes, although relatively high parous rates were recorded in both habitats. Based on the distribution of P. orientalis recorded in this study, this species is the most likely vector of VL in the endemic focus in the White Nile area. Further investigation is required to elucidate the seasonal abundance and distribution of the vector, as well as the transmission season of VL in both habitats so that appropriate control strategies for the vector can be designed.     

A lipophosphoglycan-independent development of Leishmania in permissive sand flies

Leishmaniases are serious parasitic diseases the etiological organisms of which are transmitted by insect vectors, phlebotominae sand flies. Two sand fly species, Phlebotomus papatasi and P. sergenti, display remarkable specificity for Leishmania parasites they transmit in nature, but many others are broadly permissive to the development of different Leishmania species. Previous studies have suggested that in 'specific' vectors the successful parasite development is mediated by parasite surface glycoconjugates and sand fly lectins, however we show here that interactions involving 'permissive' sand flies utilize another molecules. We did find that the abundant surface glycoconjugate lipophosphoglycan, essential for attachment of Leishmania major in the specific vector P. papatasi, was not required for parasite adherence or survival in the permissive vectors P. arabicus and Lutzomyia longipalpis. Attachment in several permissive sand fly species instead correlated with the presence of midgut glycoproteins bearing terminal N-acetyl-galactosamine and with the occurrence of a lectin-like activity on Leishmania surface. This new binding modality has important implications for parasite transmission and evolution. It may contribute to the successful spreading of Leishmania due to their adaptation into new vectors, namely transmission of L. infantum by Lutzomyia longipalpis; this event led to the establishment of L. infantum/chagasi in Latin America.     

The differentiation of the leishmaniasis vector Phlebotomus papatasi from the suspected vector P.bergeroti (Diptera: Phlebotominae)

ABSTRACT. The inability to distinguish females of Phlebotomus papatasi (Scopoli) and P.bergeroti Parrot reliably is of considerable epidemiological significance since papatasi is a well-known vector, and bergeroti is a suspected vector, of cutaneous leishmaniasis. Previous methods for distinguishing them are either vague (pharyngeal armature) or unreliable (sper-mathecae). Detailed evaluation of the relative length of the ascoid on the fourth antennal segment shows it to be an unambiguous and reliable character for distinguishing both sympatric and allopatric populations. The biological differentiation of the two species is reviewed.     

Sandfly (Diptera, Psychodidae, Phlebotominae) fauna of South-Western Pakistan. 1. Diagnostic morphology of Phlebotomus papatasi (Scopoli), Ph. bergeroti (Parrot) and Ph. salehi (Mesghali)

A survey was conducted to study the morphology of the sandfly fauna in South-Western Pakistan (Balochistan). During the revision of different genera of sandflies the specimens of Phlebotomus papatasi (Scopoli) (N = 720), Ph. bergeroti Parrot (N = 30) and Ph. salehi Mesghali (N = 70) were encountered in various localities. These localities appear to be new records of the subgenus in the literature to date. Ph. bergeroti is reported for the first time from Pakistan and Ph. salehi from Balochistan as well. Characters of these three Pakistanese Phlebotomus are compared with the published data of these species from other countries. Keys for the identification of Pakistanese Phlebotomus are also constructed. Two female Ph. papatasi collected from indoors out of 132 female flies (1.5%) were found positive with flagellate infection in pharynx and midgut. The possible vectorial role of these flies is also discussed. Further surveys are necessary in parts of the country that have not been systematically surveyed.     

Interspecific hybridization and genetic variability of Phlebotomus sandflies

The first successful hybridization is reported between Phlebotomus papatasi and P. duboscqi, two important Old World sandfly vectors of leishmaniasis and other diseases. Laboratory strains of P. papatasi and P. duboscqi were separable by six diagnostic enzyme loci: Est-3, Idh-1, Mdh-2, Mpi, Tre-1 and Tre-3. Hybrids between the two species were verified by the recovery of heterozygous isozyme patterns for the diagnostic loci. No F2 or backcross progeny were obtained. P. papatasi was separated from P. bergeroti by three diagnostic enzyme loci: Est-3, Mpi and Pgd. The isozyme patterns of P. bergeroti contain elements of both P. duboscqi and P. papatasi, although seven diagnostic loci (Est-3, Idh-1, Me, Mpi, Pgd, Tre-1 and Tre-3) separated P. bergeroti from P. duboscqi. Genetic variability profiles of the three species were established for 20 enzyme loci. Three geographically distant strains of P. papatasi from Calcutta, Maharashtra and Israel had isozyme genetic distances of < 0.05. The recently established Calcutta strain showed an unexpectedly low genetic variability with only one (Idh-2) of 20 loci being polymorphic (average heterozygosity of 1.9%) in contrast to 5-8 polymorphic loci (10-12% heterozygosity) in the Maharashtra and Israel strains. Mass and single pair crosses between the three P. papatasi strains were fertile with normal progeny numbers. Thus we found no signs of speciation in P. papatasi.     

Distribution of phlebotomine sandflies and the rate of their infection with Leishmania promastigotes in the Algarve, Portugal

Four species of sandflies: Phlebotomus (Larroussius) perniciosus Newstead, Sergentomyia minuta (Rondani), Phlebotomus (Paraphlebotomus) sergenti Parrot and Phlebotomus (Larroussius) ariasi Tonnoir, were collected, by aspiration and light traps, from three dog kennels and an area of high prevalence of human and canine visceral leishmaniasis in the Algarve, Portugal. Midgut infections with leishmanial promastigotes were observed only in P. perniciosus with a minimum infection rate of 5%. The engorgement, gravidity, population dynamics and sex ratios of the sandflies, and the temperature, source and altitude of collection sites were examined. Host preferences were noted for P. perniciosus.     

Phlebotomus sergenti (Parrot, 1917) identified as Leishmania killicki host in Ghardaïa, south Algeria

Since 2005, an outbreak of human cutaneous leishmaniasis (CL) in Gharda?a, south Algeria, was studied and one output of these investigations was the identification of two Leishmania species, Leishmania major and Leishmania killicki, as the CL causative agents. In the present study, we were curious to focus on sand fly fauna present in this area and detection of Leishmania-positive sand fly females. Sand flies (3717) were collected during two seasons using sticky papers and CDC light traps in urban, rural and sylvatic sites. Twelve Phlebotomus species were identified. Phlebotomus papatasi was dominant in the urban site while Phlebotomus sergenti and Phlebotomus riouxi/chabaudi were dominant in the sylvatic site. Out of 74 P. sergenti females captured by CDC light traps in the sylvatic site populated by Gharda?as' Gundi (Massoutiera mzabi), three ones were hosting Leishmania promastigotes. PCR-RFLP and sequencing of seven single-copy coding DNA sequences identified the promastigotes as L. killicki. Furthermore, laboratory experiments revealed that L. killicki isolate sampled from a CL patient inhabiting the studied region develop well in P. sergenti females. Our findings strongly suggest that the human cutaneous leishmaniases caused by L. killicki is a zoonotic disease with P. sergenti sand flies acting as hosts and vectors and gundi rodents as reservoirs.     

Genetic polymorphism in sympatric species of the genus Phlebotomus, with special reference to Phlebotomus perniciosus and Phlebotomus longicuspis (Diptera, Phlebotomidae)

The Random Amplified Polymorphic DNA assay was used to study genetic variation within and between five Phlebotomus species belonging to three subgenera: P. (Larroussius) ariasi, P. (L.) longicuspis, P. (L.) perniciosus, P.(Paraphlebotomus) sergenti and P. (Phlebotomus) papatasi sympatric in southern Spain and proven vector of leishmaniasis. Two cluster analysis were proposed: one according to sandfly species and populations, the second according individual specimens of Phlebotomus perniciosus, Phlebotomus longicuspis s.l. and intermediate morphological specimens between these species. The results obtained are closely correlated with the taxonomy classically accepted for the subgenera and with the automatic classifications made by other authors which use morphological and isoenzymatic data. The validity of the species Phlebotomus longicuspis is also discussed.     

Entomological survey of sandflies (Diptera, Psychodidae) in the province of L'Aquila (Abruzzo)]

A survey on phlebotomine sandflies (Diptera, Psychodidae) was carried out in the province of L'Aquila, Abruzzo region (Italy). Ten collecting sites at altitudes between 700 and 1,070 m a.s.l., produced a total of 324 specimens (81.1% males), 72.86% being Phlebotomus perniciosus, 3.08% P. mascittii, 0.30% P. papatasi and 23.76% Sergentomyia minuta. The collecting sites at 1,070, 950 and 775 m a.s.l. are the highest levels recorded in Italy for P. perniciosus, P. mascittii and P. papatasi, respectively. P. perfiliewi, the proven vector of cutaneous leishmaniasis (CL) in the Abruzzo region (Maroli et al., 1987) was absent. The probable role of P. perniciosus in the transmission of the sporadic CL cases reported from the area is discussed.     

Leishmania tropica: intraspecific polymorphisms in lipophosphoglycan correlate with transmission by different Phlebotomus species

Lipophosphoglycan (LPG) is a dominant surface molecule of Leishmania promastigotes which has been shown to be critical for parasite-sand fly vector interactions. To provide additional evidence for its importance in transmission, the LPGs from three Leishmania tropica strains that differ in their capability to infect sand flies, were biochemically characterized. One of these strains, ISER/IL/98/LRC-L747, was isolated from a Phlebotomus sergenti female collected in the Judean Desert close to Jerusalem. The other strains originated from a different focus in the Galilee region of northern Israel. One was isolated from a patient (MHOM/IL/02/Ofri-LRC-L863) and the other from a naturally infected Phlebotomus arabicus female (IARA/IL/00/Amnunfly1-LRC-L810). The LPG structures of the isolates from the Galilee (L863 and L810) were similar to each other, but differed in the LPG repeat units from the Judean Desert isolate (L747). The terminal sugar in the side chains of the repeat units of LPG purified from L863 and L810 was beta-galactose and was not capped with glucose, unlike L747 and a previously characterized L. tropica strain from Iraq (L36). Since L810 was isolated from P. arabicus and L747 from P. sergenti, variations in the structure of their LPGs may explain their capacity to infect different sand fly species.     

Distribution,species composition and relative abundances of sandflies in North Waziristan Agency,Pakistan

This study was conducted to investigate the diversity of sandflies (Psychodidae: Phlebotominae) and the incidence of leishmaniasis in three villages of North Waziristan Agency, Pakistan. Sandflies were sampled monthly during 2012, at dusk and dawn, in selected indoor habitats including both bedrooms and animal sheds using a knock‐down spray catch method. A total of 3687 sandflies were collected, including 1444 individuals in Drezanda, 1193 in Damdil and 1050 in Dattakhel. This study revealed 14 species of two genera, Phlebotomus (Phlebotomus sergenti, Phlebotomus papatasi, Phlebotomus caucasicus, Phlebotomus kazeruni, Phlebotomus alexandri and Phlebotomus salehi) and Sergentomyia (Sergentomyia dentate, Sergentomyia baghdadis, Sergentomyia babu, Sergentomyia theodori, Sergentomyia sumbarica, Sergentomyia dreyfussitur kestanica, Sergentomyia hogsoni pawlowskyi and Sergentomyia fallax afghanica) (both: Diptera: Psychodidae). Phlebotomus sergenti was the most abundant species (42.1%), followed by S. dentata (17.7%) and S. baghdadis (17.4%). The number of males collected represented about twice that of female flies, and the maximum number was collected in July, followed by August. The determination of the species composition of sandfly populations, seasonal variations, relative abundances and estimations of infection in the vector population may provide information about the dynamics of leishmaniasis transmission that is useful in planning vector control activities.