RESUMO
Phlebotomus (Paraphlebotomus) riouxi Depaquit, Léger & Killick-Kendrick (Diptera: Psychodidae) was described as a typological species based on a few morphological characters distinguishing it from Phlebotomus (Paraphlebotomus) chabaudi Croset, Abonnenc & Rioux. The naming of P. riouxi coincided with its incrimination as a rural vector of Leishmania tropica Wright (junior synonym: Leishmania killicki Rioux, Lanotte & Pratlong) in Tataouine governorate, an arid region of southern Tunisia. The current report finds insufficient evidence to incriminate either phlebotomine sandfly as a vector of L. tropica in North Africa. Phlebotomus riouxi was found not to have the characteristics of a phylogenetic or biological species, and therefore it is synonymized with P. chabaudi. Both taxa were recorded together for the first time in Tunisia, in Tataouine, where three of 12 males showed intermediate morphology and both sexes of each taxon were not characterized by specific lineages of the nuclear gene elongation factor-1α or the mitochondrial gene cytochrome b, for which a long 3' terminal fragment is recommended for phlebotomine phylogenetics. This case study indicates that the eco-epidemiology of leishmaniasis should focus more on identifying key components of vectorial transmission that are susceptible to interventions for disease control, rather than on defining sibling species of vectors.
Assuntos
Proteínas de Insetos/genética , Phlebotomus/classificação , Argélia , Animais , Núcleo Celular/genética , Citocromos b/genética , Feminino , Masculino , Proteínas Mitocondriais/genética , Dados de Sequência Molecular , Phlebotomus/anatomia & histologia , Phlebotomus/genética , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , TunísiaRESUMO
A new protocol was developed to overcome obstacles to the high-throughput sequence analysis of the 716-717 nucleotides at the carboxyl terminal of the mitochondrial gene cytochrome b (cyt b) of the myiasis flies Chrysomya bezziana and Wohlfahrtia magnifica. For both of these obligate parasites, cyt b haplotypes provide diagnostic markers for phylogeographic populations, markers that identify the origins of emerging populations causing economically important myiasis in livestock and, in the case of C. bezziana (Old World screwworm fly), could help select reproductively-compatible populations for use in the Sterile insect technique as part of area wide integrated pest management. High sequence quality is important for unambiguously detecting the few mutations that are diagnostic for regional cyt b haplotypes and their lineages. A key innovation is the design of a new forward primer for the specific PCR amplification and high-quality sequencing of cyt b. The improved protocol will facilitate the use of this established comparative cyt b sequence analysis, not only by teams lacking the resources for whole genome sequencing (WGS) but also by those requiring reference sequences for developing comparative mitogenomics based on WGS.
Assuntos
Citocromos b/genética , DNA Mitocondrial/genética , Dípteros/classificação , Dípteros/genética , Filogeografia , Reação em Cadeia da Polimerase/métodos , Animais , Entomologia/métodos , Testes Genéticos/métodos , Haplótipos , Miíase/etiologia , Análise de Sequência de DNA/métodosRESUMO
The Old World screwworm (OWS) fly, Chrysomya bezziana, is an obligate parasite of livestock, and the myiasis caused by its larval infestations is economically important in Indonesia. The current spatial distribution of such a pest depends on two main factors: the current environmental conditions in which it can survive; and, its ability to occupy those environments by dispersal, which can be inferred from phylogeography and population genetics. These indicate that all OWS flies in Indonesia have mitochondrial cytochrome b (cyt b) haplotypes of the Asian lineage, and the regional separation of its four sub-lineages is the result of infrequent long-distance dispersal. We report the first investigation to associate regional cyt b sub-lineages of the OWS fly with environmental variables. Principal Components Analysis was used to demonstrate that these sub-lineages are associated with very similar macro-climates throughout Indonesia. Then, a species distribution model for the OWS fly in Indonesia was obtained by using the Maxent program. This indicated that elevation captured information not given by other environmental variables, and cattle density provided the most useful information by itself. The results of our study provide some important leads for future research, which will require better, stratified sampling.
Assuntos
Dípteros/crescimento & desenvolvimento , Filogeografia , Animais , Bovinos , Citocromos b/genética , DNA Mitocondrial/genética , Genética Populacional , Genótipo , Geografia , Haplótipos , IndonésiaRESUMO
The Food and Agriculture Organization of the United Nations (FAO) and the International Atomic Energy Agency (IAEA) have supported a Co-ordinated Research Project (CRP) on 'Applying GIS and population genetics for managing livestock insect pests'. This six-year CRP (2008-2013) focused on research aimed at under-pinning the Area-Wide Integrated Pest Management (AW-IPM) of populations of tsetse and screwworm flies, and this introductory paper to the Special Issue integrates the findings of the CRP participants and discusses them in a broader context. The tools and techniques for mapping and modelling the distributions of genetically-characterised populations of tsetse and screwworm flies are increasingly used by researchers and managers for more effective decision-making in AW-IPM programmes, as illustrated by the reports in this Special Issue. Currently, the insect pests are often characterized only by neutral genetic markers suitable for recognizing spatially isolated populations that are sometimes associated with specific environments. Two challenges for those involved in AW-IPM are the standardization of best practice to permit the efficient application of GIS and genetic tools by regional teams, and the need to develop further the mapping and modelling of parasite and pest phenotypes that are epidemiologically important.
Assuntos
Dípteros/classificação , Dípteros/crescimento & desenvolvimento , Ectoparasitoses/veterinária , Controle de Insetos/métodos , Filogeografia , Animais , Ectoparasitoses/parasitologia , Ectoparasitoses/prevenção & controle , Genética Populacional , Sistemas de Informação Geográfica , GadoRESUMO
BACKGROUND: Fars province lies to the south of the main foci of zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major in central and northern Iran, and its ZCL foci might have emerged more recently because of different transmission cycles. However, there have been limited studies of the parasites infecting the regional sandfly vectors. METHODS: The diversities of sandflies and the Leishmania parasites infecting female sandflies were assessed for different habitats in Fars ZCL foci, 2008-2009, using standardized sandfly trapping and characterization of ribosomal DNA haplotypes of parasites. RESULTS: Vector diversity was similar to that in the main Iran ZCL foci, but parasite diversity was lower. Only Le. major was detected in Fars sandflies. Most infections were found in the abundant vector Phlebotomus papatasi collected in rodent burrows. Infections were detected for the first time in Iran in the related P. bergeroti. CONCLUSIONS: The failure to detect other gerbil parasites (Le. turanica, Le. gerbilli) is explained by the absence of one reservoir host, the great gerbil Rhombomys opimus. Other gerbils (Meriones species) may be the regional reservoir hosts, but transmission modelling is required for a better understanding of the emergence and stability of ZCL foci in Fars and other Iranian provinces.
Assuntos
Gerbillinae/parasitologia , Leishmania/isolamento & purificação , Leishmaniose Cutânea/parasitologia , Psychodidae/parasitologia , Animais , DNA de Protozoário/genética , DNA Ribossômico/análise , Reservatórios de Doenças/parasitologia , Feminino , Insetos Vetores/parasitologia , Irã (Geográfico) , Leishmaniose Cutânea/veterinária , Phlebotomus/parasitologia , Psychodidae/genética , Doenças dos Roedores/parasitologia , Análise de Sequência de DNARESUMO
Phylogenetic, genealogical and population relationships of Chrysomya bezziana, the Old World screwworm fly (OWSF), were inferred from DNA sequences of mitochondrial cytochrome b (cyt b), nuclear elongation factor-1α (EF-1α) and nuclear white eye colour (white), using sequences of Chrysomya megacephala and Chrysomya rufifacies as outgroups. Cyt b (717bp, 754 specimens), EF-1α (361bp, 256 specimens) and white (577bp, 242 specimens) were analysed from up to two African and nine Asian countries, including 10 Indonesian islands. We show that OWSF occurs as distinctive African and Asian lineages based on cyt b and white, and that there is a marked differentiation between Sumatran and Javan populations in Indonesia, supported by the genealogy and analysis of molecular variance of cyt b alone. Four cyt b sub-lineages are recognised in Asia: only 2.1 occurs on the Asian mainland, from Yemen to Peninsular Malaysia; only 2.2, 2.3 and 2.4 occur in central Indonesia; 2.4 predominates on New Guinea; and 2.1 co-occurs with others only on Sumatra in western Indonesia. This phylogeography and the genetic distances between cyt b haplotypes indicate pre-historic, natural dispersal of OWSF eastwards into Indonesia and other Malesian islands, followed by vicariant evolution in New Guinea and central Indonesia. OWSF is absent from Australia, where there is surveillance for importation or natural invasion. Judged by cyt b haplotype markers, there is currently little spread of OWSF across sea barriers, despite frequent shipments of Australian livestock through Indonesian seas to the Middle East Gulf region. These findings will inform plans for integrated pest management, which could be applied progressively, for example starting in East Nusa Tenggara (central Indonesia) where OWSF has regional cyt b markers, and progressing westwards to Java where any invasion from Sumatra is unlikely. Cyt b markers would help identify the source of any re-emergence in treated areas.
Assuntos
Dípteros/classificação , Filogenia , Animais , Ásia , Citocromos b/genética , Dípteros/genética , Dípteros/fisiologia , Proteínas de Insetos/genética , Dados de Sequência Molecular , Fator 1 de Elongação de Peptídeos/genética , Controle de Pragas , FilogeografiaRESUMO
Phlebotomus ariasi is one of the two sandflies transmitting the causative agent of zoonotic leishmaniasis, Leishmania infantum, in France and Iberia, and provides a rare case study of the postglacial re-colonization of France by a Mediterranean species. Four DNA sequences were analysed-mitochondrial cytochrome b (cyt b), nuclear elongation factor-1α (EF-1α) and two anonymous nuclear loci-for 14-15 French populations and single populations from northeast Spain, northwest Spain, Portugal and Morocco. The presence of cryptic sibling species was not revealed by phylogenetic analyses and testing for reproductive isolation between sympatric populations defined by the two most divergent cyt b haplogroups. No locus was shown to be under positive directional or balancing selection and, therefore, molecular variation was explained demographically. Each nuclear locus showed shallow isolation by distance from Portugal to the French Pyrenees, but for both cyt b and EF-1α there was then a step change to the upland Massif Central, where leading-edge populations showed low diversity at all loci. Multiple genetic divergences and population expansions were detected by analyses of cyt b and dated to the Pleistocene. Endemicity of one cyt b sub-lineage suggested the presence of a refuge north of the Pyrenees during the last glacial period. Monopolization of the Massif Central by genetically differentiated populations of P. ariasi might possibly hinder the northwards spread of leishmaniasis.
Assuntos
Demografia , Variação Genética , Genética Populacional , Phlebotomus/genética , Filogenia , Animais , Sequência de Bases , Teorema de Bayes , Citocromos b/genética , Primers do DNA/genética , História Antiga , Região do Mediterrâneo , Repetições de Microssatélites/genética , Modelos Genéticos , Dados de Sequência Molecular , Proteínas Nucleares/genética , Dinâmica Populacional/história , Seleção Genética , Análise de Sequência de DNARESUMO
Leishmaniasis emergence in Europe is reviewed, based on a search of literature up to and including 2009. Topics covered are the disease, its relevance, transmission and epidemiology, diagnostic methods, treatment, prevention, current geographical distribution, potential factors triggering changes in distribution, and risk prediction. Potential factors triggering distribution changes include vectorial competence, importation or dispersal of vectors and reservoir hosts, travel, and climatic/environmental change. The risk of introducing leishmaniasis into the European Union (EU) and its spread among Member States was assessed for the short (2-3 years) and long term (15-20 years). There is only a low risk of introducing exotic Leishmania species because of the absence of proven vectors and/or reservoir hosts. The main threat comes from the spread of the two parasites endemic in the EU, namely Leishmania infantum, which causes zoonotic visceral and cutaneous leishmaniasis in humans and the domestic dog (the reservoir host), and L. tropica, which causes anthroponotic cutaneous leishmaniasis. The natural vector of L. tropica occurs in southern Europe, but periodic disease outbreaks in Greece (and potentially elsewhere) should be easily contained by surveillance and prompt treatment, unless dogs or other synanthropic mammals prove to be reservoir hosts. The northward spread of L. infantum from the Mediterranean region will depend on whether climate and land cover permit the vectors to establish seasonal biting rates that match those of southern Europe. Increasing dog travel poses a significant risk of introducing L. infantum into northern Europe, and the threat posed by non-vectorial dog-to-dog transmission should be investigated.
Assuntos
Leishmaniose/epidemiologia , Doenças Transmissíveis Emergentes , Europa (Continente)/epidemiologia , Humanos , Leishmaniose/diagnóstico , Leishmaniose/tratamento farmacológico , Leishmaniose/etiologia , Leishmaniose/prevenção & controle , Vigilância da PopulaçãoRESUMO
Diagnostic molecular markers for the females of Phlebotomus (Paraphlebotomus) caucasicus and P. mongolensis were sought by characterizing from individual Iranian specimens a gene fragment, namely mitochondrial cytochrome b, that had previously proven useful for the taxonomy of phlebotomine sandflies. Males of both species were used as reference material because their external genitalia provide the only diagnostic morphological characters. A phylogenetic analysis of the new sequences, and those previously reported for P. grimmi, found no support for recognizing more than one species (P. caucasicus s.l.) in Iran. Most of the genetic variation was geographical. An absence of lineage sorting was demonstrated, and it is proposed that any search for species-specific molecular markers for these three taxonomic species should be continued by applied biologists only if there is better evidence for associating any one of them with phenotypes important for understanding the transmission of Leishmania species in foci of zoonotic cutaneous leishmaniasis.
Assuntos
Citocromos b/genética , Genes Mitocondriais/genética , Phlebotomus/classificação , Phlebotomus/genética , Animais , DNA/genética , Feminino , Marcadores Genéticos , Haplótipos , Irã (Geográfico) , Masculino , Filogenia , Especificidade da EspécieRESUMO
A fragment of the mitochondrial (mt) 16S ribosomal RNA gene was amplified by PCR and sequenced from individual adult scorpions of the genus Androctonus, which were sampled from central and southern Tunisia and identified using an explicit set of morphological characters. Phylogenetic analyses placed the mtDNA haplotypes in three well-supported monophyletic lineages, corresponding to the morphospecies Androctonusaeneas, Androctonusamoreuxi and Androctonusaustralis. The latter species was the most abundant and widespread, and it was characterized by two mtDNA sub-lineages each of which predominated only north or south of the Chott el Jerid, a seasonally flooded saline depression that divides non-Mediterranean Tunisia. The divergence of the two mtDNA lineages was dated by mtDNA molecular clocks, indicating that the formation of the Chott el Jerid is unlikely to have been the barrier generating the vicariant evolution of the two lineages of A. australis, although it may have impeded their mixing following secondary contact. Both regional mtDNA lineages were found in A. australis hector and A. australisgarzonii, indicating that these two morphological forms are neither monophyletic nor geographically isolated and, therefore, should not be treated as species or subspecies. It is recommended that no subspecies of A. australis should be recognized in North Africa and toxicologists should cease the taxonomic error of referring to a species "Androctonus australis Hector". The morphological form "hector" has no proven association with an increased risk of scorpionism compared with "garzonii". However, it might be prudent to produce anti-venom in Tunisia by using both morphological forms of A. australis collected each side of the Chott el Jerid, because of the evidence for regional variation in toxins. The highest risk for scorpion stings occurs in the central region, where the new diagnostic markers should be used to discover any association between Androctonus species and scorpionism.
Assuntos
Aracnídeos/classificação , Animais , Antivenenos/uso terapêutico , Aracnídeos/anatomia & histologia , Aracnídeos/genética , Análise por Conglomerados , DNA Mitocondrial/química , DNA Mitocondrial/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Mordeduras e Picadas de Insetos/terapia , Masculino , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , TunísiaRESUMO
A previous study had identified an African and an Asian race of the Old World screwworm fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), based on the 3' terminal 279 basepairs (bp) of the mitochondrial cytochrome b gene. The current study improved the phylogeographic resolution of cytochrome b for this species by characterizing more of the gene (the 3' terminal 715 bp) and by sampling more geographical populations, including Oman, Iran, Hong Kong and the Indonesian islands of Sulawesi and East Sumba. Strong support was found for recognizing an African race, but not for a monophyletic Asian race. The cladistic and genealogical relationships among the Asian populations were complex. There was sufficient genetic homogeneity throughout separate regions (mainland Asia and each Indonesian island) to suggest that there are no reproductive barriers within each region that might necessitate the production of more than one strain for control by the sterile insect technique (SIT). Primers were designed for the amplification by polymerase chain reaction of two nuclear loci, the highly conserved elongation factor-1alphagene and the less conserved white gene, and the preliminary results indicated that these genes showed the same pattern of small-scale regional variation as cytochrome b. The cytochrome b haplotypes are useful markers for identifying the geographical origins of any emerging infestations of the species: the absence of Indonesian and African haplotypes in the Middle East demonstrates that the large-scale transport of livestock is not spreading Old World screwworm.
Assuntos
Núcleo Celular/genética , Citocromos b/genética , Dípteros/genética , Mitocôndrias/genética , Animais , Pareamento de Bases , DNA/genética , DNA/isolamento & purificação , Primers do DNA , Dípteros/classificação , Amplificação de Genes , Geografia , FilogeniaRESUMO
Fly larvae were collected from 181 cases of traumatic myiasis in livestock in 10 regions of four countries in the Middle East Gulf region: Iran, Iraq, Saudi Arabia and Oman. The predominant fly species responsible for cases was the Old World screwworm (OWS) fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae). In cases from Iran and Oman, which included non-OWS fly species, OWS fly was found solely responsible for 67.6% of cases and jointly with other fly species for a further 12.7% of cases. The major hosts were sheep and goats, together comprising 84.6% of the total, which reflects their predominance among the livestock of these Gulf countries. The major site of wounding on sheep and goats was the tail (40.3%), followed by female genitalia (14.0%). The 3' terminal 715 nucleotides of the mitochondrial cytochrome b gene were sequenced for 178 larvae of OWS. Five haplotypes were identified: three had been recorded previously in the region (two were common throughout and one was unique to Oman), and two were newly identified, one from southern Iraq and the other from Saudi Arabia, both in regions sampled for the first time. The haplotypes varied from one another only at one or two nucleotide sites, equivalent to an intraspecific difference of 0.14-0.28% across the entire 715-bp fragment. There was a single statistically significant association between host species and haplotype in Saudi Arabia, a first such record for OWS fly. The small degree of genetic diversity between geographical populations of OWS fly within the Gulf region suggests that a single Gulf colony could be used to implement the sterile insect technique within an integrated control programme.
Assuntos
Dípteros/genética , Variação Genética , Miíase/veterinária , Infecção por Mosca da Bicheira/veterinária , Esterilização/métodos , Animais , Animais Domésticos/parasitologia , Feminino , Irã (Geográfico)/epidemiologia , Iraque/epidemiologia , Masculino , Miíase/epidemiologia , Miíase/genética , Omã/epidemiologia , Arábia Saudita/epidemiologia , Infecção por Mosca da Bicheira/epidemiologia , Infecção por Mosca da Bicheira/genéticaRESUMO
Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a major cause of traumatic myiasis in livestock in Central and Eastern Europe and in countries bordering the Mediterranean. The present study explored the utility of external body characters, genitalia characters and mitochondrial DNA characters for identification of this and related species in the subfamily Paramacronychiinae. Sequence analyses of the 3' terminal 273 bp of the mitochondrial cytochrome b gene revealed two lineages of W. magnifica, one from Spain and France and the other from the rest of Eurasia, differing by only two base pairs. Phylogenetic analysis of cytochrome b showed that W. magnifica and Wohlfahrtia vigil Walker were sister species; this conclusion was not contradicted by a phylogenetic analysis of the morphological characters. Based on cytochrome b, the genetic distance between specimens of W. vigil from Europe and North America was sufficiently large to justify the recognition of more than one species. A new species, Wohlfahrtia monegrosensis, from northern Spain, was described, based on morphology and cytochrome b. A unique combination of external body characters of males or females were diagnostic for W. magnifica, the W. vigil group and Wohlfahrtia bella, but only the genitalia characters were diagnostic for all nine species studied.
Assuntos
Citocromos b/genética , DNA Mitocondrial/genética , Dípteros/genética , Miíase/genética , Miíase/veterinária , Ração Animal , Animais , Regiões Árticas , Ásia , Canadá , Dípteros/anatomia & histologia , Dípteros/classificação , Europa (Continente) , Feminino , Genitália/anatomia & histologia , Geografia , Masculino , Doenças Parasitárias/genética , Filogenia , Estados UnidosRESUMO
Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae), is the most important cause of traumatic myiasis in the southern Palaearctic region. Larval stages are obligate parasites and the wounds caused by infestations are very similar to those caused by Old and New World screwworm flies. During the last decade, W. magnifica appears to have expanded its range to parts of northern and central Morocco, and to Crete, Greece. Specimens of W. magnifica were collected in Morocco and Crete either as larvae (preserved in 80% ethanol) or as adults (dry-pinned). Comparison specimens were collected in Spain, Hungary and mainland Greece. A DNA fragment containing the 3' 715 base pairs of the mitochondrial cytochrome b gene was amplified by polymerase chain reaction from each of 132 larvae or adults of W. magnifica and the amplicons were directly sequenced and analysed phylogeographically. Twelve cytochrome b haplotypes were detected. All haplotypes from Morocco belonged to a lineage that included specimens from the Iberian peninsula, and restricted mixing of central and northern populations in Morocco was demonstrated. Cytochrome b haplotyping combined with an analysis of larval size provided clear evidence of multiple infestations of hosts in all geographical areas, with one quarter of wounds containing larvae from two to at least four females. More than 80% of specimens from Crete contained a haplotype predominating in mainland Greece and Hungary. Our survey indicated that wohlfahrtiosis was more widespread in northern and central Morocco than previously recorded by government veterinarians. However, the prevalence of wohlfahrtiosis was low (< 1%). The high genetic diversity of Moroccan populations is consistent with longterm endemicity, rather than recent introduction. Crete showed a higher prevalence of wohlfahrtiosis (< or = 15%) and less genetic diversity of W. magnifica, which is consistent with a recent introduction. The western and eastern Mediterranean lineages may have been isolated in different Pleistocene ice-age refugia, from which there has been limited post-glacial dispersal.
Assuntos
DNA Mitocondrial/genética , Dípteros/genética , Surtos de Doenças/veterinária , Biologia Molecular , Miíase/veterinária , Animais , Clima , Citocromos b/genética , Dípteros/classificação , Ecossistema , Europa (Continente) , Variação Genética , Grécia/epidemiologia , Larva , Marrocos/epidemiologia , Miíase/epidemiologia , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Spatio-temporal modelling of the distributions of the leishmaniases and their sandfly vectors is reviewed in relation to climate change. Many leishmaniases are rural zoonoses, and so there is a foundation of descriptive ecology and qualitative risk assessment. Dogs are widespread reservoir hosts of veterinary importance. Recent statistical modelling has not always produced novel general conclusions, exemplifying the difficulty of applying models outside the original geographical region. Case studies are given for transmission cycles involving both cutaneous and visceral leishmaniasis in the Old World and the Americas. An important challenge is to integrate statistical spatial models based mainly on climate with more explanatory biological models. Ecological niche models pose difficulties because of the number of assumptions. A positive association has been reported between the El Niño cycle and the annual incidence of visceral leishmaniasis in Brazil, but more basic research is needed before tackling other climate-change scenarios, including leishmaniasis emergence in northern Europe.
Assuntos
Efeito Estufa , Insetos Vetores/parasitologia , Leishmaniose/epidemiologia , Leishmaniose/veterinária , Psychodidae/parasitologia , Animais , Clima , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/transmissão , Doenças Transmissíveis Emergentes/veterinária , Reservatórios de Doenças/veterinária , Humanos , Insetos Vetores/crescimento & desenvolvimento , Leishmaniose/prevenção & controle , Leishmaniose/transmissão , Periodicidade , Psychodidae/crescimento & desenvolvimento , Saúde Pública , Medição de Risco , Estações do Ano , ZoonosesRESUMO
OBJECTIVE: To identify and understand the natural transmission cycles of Leishmania in Iranian sandflies. METHOD: Nested PCR protocols were developed to amplify two regions of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA gene, and a microsatellite DNA region of ITS2), which were species-specific by DNA sequence or fragment size. RESULTS: The PCR assays detected in Iranian sandflies not only Leishmania major but also for the first time L. turanica and L. gerbilli sensu lato, two other parasites of the great gerbil. All three parasites were found in the northeast and centre of Iran, in two foci of rural Zoonotic Cutaneous Leishmaniasis (ZCL) caused by L. major. Fifty infections were detected in common sandfly species: at least six geographically differentiated haplotypes of L. major in four to five sandfly species; one strain of L. gerbilli s.l. in five to six sandfly species and one strain of L. turanica in one sandfly species. CONCLUSION: Past conclusions about the transmission cycles of L. major in Iran should be treated with caution. Careful molecular eco-epidemiological investigations are essential for modelling the roles of different sandfly species in maintaining and spreading ZCL foci. Even if non-pathogenic to humans, frequent inoculations of L. turanica by sandflies might alter the efficacy of vaccines against L. major. Phlebotomus papatasi is probably the key vector in many ZCL foci because of its abundance and high infection rates with both L. major and L. turanica.
Assuntos
DNA de Protozoário/genética , Gerbillinae/parasitologia , Leishmania/isolamento & purificação , Leishmaniose Cutânea/transmissão , Psychodidae/parasitologia , Animais , DNA Recombinante/genética , Reservatórios de Doenças , Feminino , Humanos , Irã (Geográfico) , Leishmania/genética , Leishmaniose Cutânea/genética , Leishmaniose Cutânea/veterinária , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Análise de Sequência de DNA/métodos , Especificidade da EspécieRESUMO
Leishmania infantum is the causative agent of infantile visceral leishmaniasis (IVL) in the Mediterranean Basin and, based on isoenzyme typing of a few isolates from patients and domestic dogs, this parasite was considered to predominate in the Kaleybar focus of IVL in northwest Iran. However, in the current investigation only one out of five sandfly infections was found to be L. infantum, based on PCR detection and sequencing of parasite internal transcribed spacer (ITS) rDNA infecting Phlebotomus perfiliewi transcaucasicus. The four other infections were of haplotypes of L. tropica, the causative agent of anthroponotic cutaneous leishmaniasis in the Middle East and a parasite occasionally detected in the viscera of dogs and patients in Iran and elsewhere. The widespread distribution of L. tropica in the Kaleybar focus suggests that this parasite is not a transient introduction. Kaleybar has been used for a deltamethrin dog collar intervention to reduce the biting rates of the vectors of L. infantum and this has significantly reduced the incidence of Leishmania infections both in children and the domestic dog, the usual reservoir host of IVL. The implications of finding L. tropica widespread in the heart of the intervention area are discussed. Extensive and intensive typing of natural Leishmania infections is a characteristic of epidemiological investigations in the Neotropics and the current report indicates that this will also be necessary in some regions of the Old World.
Assuntos
Doenças do Cão/parasitologia , Inseticidas/administração & dosagem , Leishmania infantum/isolamento & purificação , Leishmania tropica/isolamento & purificação , Leishmaniose Visceral/parasitologia , Nitrilas/administração & dosagem , Piretrinas/administração & dosagem , Animais , Doenças do Cão/prevenção & controle , Cães , Humanos , Lactente , Irã (Geográfico) , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/veterinária , Reação em Cadeia da Polimerase/métodos , Psychodidae/parasitologiaRESUMO
Tunisian Androctonus species, for long time discussed, were recognized on the basis of mitochondrial 16S rDNA sequences. Although the analysed nucleotide sequence is rather short (about 300 bp), the obtained phlogenetic trees revealed that A. amoreuxi and A. aeneas form two well-supported sister clades against A. australis haplotypes. Each specimen of the very rare species A. aeneas showed a specific haplotype, but together formed a well-defined clade. Some A. amoreuxi specimens highlighted unidirectional mitochondrial introgression from neighbouring A. australis population. Within A. australis, previously described, subspecies subdivision (A. a .hector and A. a. garzonii) was not supported.
Assuntos
DNA Mitocondrial/genética , DNA Ribossômico/genética , Filogenia , RNA Ribossômico 16S/genética , Escorpiões/genética , Animais , Teorema de Bayes , Feminino , Variação Genética/genética , Haplótipos , Vigor Híbrido/genética , Masculino , Cadeias de Markov , Reação em Cadeia da Polimerase/métodos , Polimorfismo Genético/genética , Escorpiões/classificação , Sensibilidade e Especificidade , Análise de Sequência de DNA , Especificidade da Espécie , TunísiaRESUMO
Two PCR methods were compared for their sensitivity in detecting cultured Leishmania major, before being used to estimate infection rates in female sandflies (Phlebotomus papatasi) collected from peridomestic animal shelters and the nearby burrows of the gerbil reservoir hosts, Rhombomys opimus, in Isfahan province, central Iran. A semi-nested PCR was used to amplify a fragment of minicircle kinetoplast (k) DNA with a length and sequence diagnostic for L. major, and a nested PCR was developed to amplify a fragment containing the internal transcribed spacers of the ribosomal RNA genes (ITS-rDNA) with a sequence diagnostic for L. major. The semi-nested PCR was less sensitive than the nested PCR when using DNA extracted from cultured promastigotes of L. major, but it was more sensitive for detecting L. major in wild-caught sandflies. At the edges of two Isfahan villages, infection rates were significantly higher in P.papatasi collected outside gerbil burrows (14/28) compared with those from peridomestic animal shelters (2/21). This is the first record of L. major detected in P.papatasi from peridomestic sites in Isfahan province.
Assuntos
Leishmania major/genética , Leishmaniose Cutânea/parasitologia , Phlebotomus/parasitologia , Reação em Cadeia da Polimerase/métodos , Animais , DNA de Cinetoplasto/química , DNA de Cinetoplasto/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Feminino , Gerbillinae , Irã (Geográfico) , Leishmania major/isolamento & purificação , População Rural , Sensibilidade e Especificidade , Análise de Sequência de DNARESUMO
Phlebotomus perniciosus was identified morphologically in samples from France and northeast Spain, and individuals were then characterized at three polymorphic isoenzyme loci (by isoelectrofocusing) and at the mitochondrial DNA locus (by comparative DNA sequence analysis of a fragment of the Cytochrome b gene). The four polymorphic loci gave conflicting patterns of population relationships, which can be explained by hypothesizing different amounts of gene introgression at each locus when two distinctive lineages met in southern France or northeast Spain after isolation in southern Italy and Spain during the Pleistocene Ice Ages. P. perniciosus is an important vector of leishmania infantum and so these population differentiation studies are relevant for predicting the emergence and spread of leishmaniasis in relation to environmental changes, including climate.