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PLoS Neglected Tropical Diseases Aug 2017Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and... (Review)
Review
Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and international public health systems. However, the infections caused by protozoa of the Leishmania genus and viruses belonging to the Phlebovirus genus (family Phenuiviridae)-the most significant group of viruses transmitted by sand flies-have a relevant role for human pathology. These infections are emerging in the Mediterranean region and will likely spread in forthcoming decades, posing a complex threat to human health. Four species and 2 hybrid strains of Leishmania are pathogenic for humans in the Mediterranean Basin, with an estimated annual incidence of 239,500-393,600 cases of cutaneous leishmaniasis and 1,200-2,000 cases of visceral leishmaniasis. Among the phleboviruses, Toscana virus can cause neuroinvasive infections, while other phleboviruses are responsible for a typical "3-day fever"; the actual incidence of Phlebovirus infections in the Mediterranean area is unknown, although at least 250 million people are exposed. Here, we reviewed the current literature on epidemiology of sand fly-borne infections in the Mediterranean Basin, with a focus on humans. Our analysis indicates the need for increased public health activities directed to determine the disease burden of these infections as well as to improve their surveillance. Among the emerging challenges concerning sand fly-borne pathogens, the relationships between sand fly-borne protozoa and viruses should be considered in future studies, including epidemiological links between Leishmania and phleboviruses as well as the conditional capacity for these pathogens to be involved in interactions that may evolve towards increased virulence.
Topics: Animals; Bunyaviridae Infections; Dogs; Humans; Insect Vectors; Leishmania; Leishmaniasis; Mediterranean Region; Phlebovirus; Psychodidae
PubMed: 28796786
DOI: 10.1371/journal.pntd.0005660 -
Parasites & Vectors Feb 2018Blood-sucking phlebotomine sand flies are the vectors of the protozoan parasites Leishmania spp. Different Phlebotomus species transmit different Leishmania species...
BACKGROUND
Blood-sucking phlebotomine sand flies are the vectors of the protozoan parasites Leishmania spp. Different Phlebotomus species transmit different Leishmania species causing leishmaniases which are neglected diseases emerging/reemerging in new regions. Thirteen sand fly species, ten belonging to the medically important genus Phlebotomus and three belonging to Sergentomyia are known in Greece. An increasing number of human and dog cases are reported each year from all parts of the country including the Aegean Islands. However, no previous study has been conducted on the sand fly fauna on the islands, except for Rhodes and Samos. The aim of this study was to investigate sand fly species in eleven small Aegean islands; to understand species-specific relationships with environmental and climatic factors and to compare sand fly community parameters among islands. A risk analysis was carried out for each species using climatic and environmental variables.
RESULTS
Nine sand fly species: Phlebotomus neglectus, P. tobbi, P. similis, P. simici, P. perfiliewi, P. alexandri, P. papatasi, Sergentomyia minuta and S. dentata, were collected from the islands studied. Phlebotomus (Adlerius) sp. and Sergentomyia sp. specimens were also collected but not identified to the species level. There was a positive effect of distance from the sea on the abundance of P. neglectus, S. minuta and S. dentata, and a negative effect on the abundance of P. tobbi, P. simici and P. similis. In general, temperature preferences of sand fly populations were between 21 and 29 °C. Nevertheless, there were significant differences in terms of temperature and relative humidity preference ranges among species. The most important species found, P. neglectus, was indisputably the most adapted species in the study area with a very high reaction norm, favoring even the lower temperature and humidity ranges. Overall, the sand fly fauna in the islands was very rich but there were differences in species diversity, as indicated by the values of the Shannon-Wiener index, along with evenness and richness of the sand fly fauna between the islands and altitude ranges in the islands.
CONCLUSIONS
The study indicated that the Greek Aegean Islands, however small, maintain a rich sand fly fauna. This includes important vectors of Leishmania spp. representing a risk for parasite transmission to humans and dogs along with the danger of maintaining new Leishmania spp. if introduced to the area.
Topics: Animals; Biodiversity; Ecology; Ecosystem; Geography; Greece; Insect Vectors; Islands; Leishmaniasis; Psychodidae; Species Specificity
PubMed: 29458398
DOI: 10.1186/s13071-018-2680-4 -
PLoS Neglected Tropical Diseases May 2022Indoor Residual Spraying (IRS) is one of the interventions to control the vectors of Visceral Leishmaniasis (VL). Different insecticides are used in affected countries,...
Indoor Residual Spraying (IRS) is one of the interventions to control the vectors of Visceral Leishmaniasis (VL). Different insecticides are used in affected countries, also in the Regional Initiative for the Elimination of VL in South-East Asia. This systematic review assesses all available studies analysing the effectiveness of IRS on the key vectors of VL. The systematic review followed PRISMA guidelines, with a broad search strategy, applied to seven key databases. Inclusion criteria were studies focusing on 1) Visceral leishmaniasis 2) Indoor Residual Spraying (IRS) or synonyms, and 3) all primary research methods. 21 studies were included, five cluster randomised controlled trials (cRCTs), one randomised controlled trial (RCT), 11 intervention studies, also included were three modelling studies and one survey. 19 out of 21 included studies were published between 2009 and 2020. 18 of the studies were conducted in the context of the Regional Initiative. Effects of IRS on vector populations are positive, confirmed in terms of effectiveness and by the availability of studies. Deltamethrin and alpha-Cypermethrin reduce total sandfly counts, and/or Phlebotomus argentipes counts by up to 95% with an effect of a minimum of one month. Prolonged effects are not regularly seen. DDT has been used in India only: whereas in the 1990s a good effect could be measured, this effect waned over time. Two intervention studies, embedded in larger programmes in 2019 and 2020, replaced DDT with alpha-Cypermethrin throughout the study. Combinations of different interventions are not systematically researched, however showing some promising results, for example for the combination of IRS and Temephos. Constant monitoring of insecticide resistancies and quality delivery of IRS are confirmed as key issues for programmes. No human transmission data are available to directly relate an effect of IRS-although modelling studies confirm the effect of IRS on human transmission. Concluding, IRS continues to be an effective intervention for Phlebotomus argentipes control. Delivery requires constant monitoring and quality assurance. Further studies need to assess IRS in different geographical areas affected by VL and combinations of interventions.
Topics: Animals; DDT; Disease Progression; Humans; Insect Vectors; Insecticides; Leishmaniasis, Visceral; Phlebotomus; Psychodidae
PubMed: 35587498
DOI: 10.1371/journal.pntd.0010391 -
Revista Argentina de Microbiologia 2022Tegumentary leishmaniasis (TL) is caused by parasites of the genus Leishmania and transmitted by the sandfly species, insects belonging to the order Diptera, family...
Tegumentary leishmaniasis (TL) is caused by parasites of the genus Leishmania and transmitted by the sandfly species, insects belonging to the order Diptera, family Psychodidae. Historically, the most endemic area of TL in Argentina has been the northern region. The aim of this work was to analyze the presence and temporal variation of TL cases reported between 1985 and 2019 in Colonia Santa Rosa locality, northern Argentina. Furthermore, its clinical forms were characterized and sandflies were captured. Patients were diagnosed by smear and the Montenegro skin test. For sampling, CDC light traps were placed at 14 sites from 7pm to 7am. The correlation between vegetation cover and sandfly abundance was also studied. One hundred and twenty TL cases were diagnosed and the overall prevalence was 0.75% (≈16 000 inhabitants). Patients presented simple and multiple cutaneous leishmaniasis (88.79%) and the mucocutaneous form (10.83%). Skin lesions were more frequent on the lower extremities (46.73%). Of the total number of sandflies, Nyssomyia neivai (95%) was the predominant species followed by Migonemyia migonei (1.9%), cortelezzii complex (1.3%) and Evandromyia sallesi (0.09%). The persistent occurrence of cases and the presence of sandflies in the locality suggest the existence of endemic transmission in the area. This highlights the need to design prevention and control measures for TL in northern Argentina.
Topics: Animals; Argentina; Brazil; Humans; Insect Vectors; Leishmaniasis; Psychodidae; Rosa
PubMed: 34503860
DOI: 10.1016/j.ram.2021.06.002 -
PLoS Neglected Tropical Diseases Feb 2017Visceral leishmaniasis (VL) is an important neglected disease caused by a protozoan parasite, and represents a serious public health problem in many parts of the world....
Visceral leishmaniasis (VL) is an important neglected disease caused by a protozoan parasite, and represents a serious public health problem in many parts of the world. It is zoonotic in Europe and Latin America, where infected dogs constitute the main domestic reservoir for the parasite and play a key role in VL transmission to humans. In Brazil this disease is caused by the protozoan Leishmania infantum chagasi, and is transmitted by the sand fly Lutzomyia longipalpis. Despite programs aimed at eliminating infection sources, the disease continues to spread throughout the Country. VL in São Paulo State, Brazil, first appeared in the northwestern region, spreading in a southeasterly direction over time. We integrate data on the VL vector, infected dogs and infected human dispersion from 1999 to 2013 through an innovative spatial temporal Bayesian model in conjunction with geographic information system. This model is used to infer the drivers of the invasion process and predict the future progression of VL through the State. We found that vector dispersion was influenced by vector presence in nearby municipalities at the previous time step, proximity to the Bolívia-Brazil gas pipeline, and high temperatures (i.e., annual average between 20 and 23°C). Key factors affecting infected dog dispersion included proximity to the Marechal Rondon Highway, high temperatures, and presence of the competent vector within the same municipality. Finally, vector presence, presence of infected dogs, and rainfall (approx. 270 to 540mm/year) drove the dispersion of human VL cases. Surprisingly, economic factors exhibited no noticeable influence on disease dispersion. Based on these drivers and stochastic simulations, we identified which municipalities are most likely to be invaded by vectors and infected hosts in the future. Prioritizing prevention and control strategies within the identified municipalities may help halt the spread of VL while reducing monitoring costs. Our results contribute important knowledge to public and animal health policy planning, and suggest that prevention and control strategies should focus on vector control and on blocking contact between vectors and hosts in the priority areas identified to be at risk.
Topics: Animals; Brazil; Dog Diseases; Dogs; Humans; Insect Vectors; Leishmaniasis, Visceral; Psychodidae; Risk Assessment; Risk Factors; Spatial Analysis
PubMed: 28166251
DOI: 10.1371/journal.pntd.0005353 -
Parasites & Vectors May 2019Phlebotomine sand flies (Diptera: Psychodidae) are haematophagous insects that transmit the protozoan parasite Leishmania infantum (Kinetoplastida: Trypanosomatidae),...
BACKGROUND
Phlebotomine sand flies (Diptera: Psychodidae) are haematophagous insects that transmit the protozoan parasite Leishmania infantum (Kinetoplastida: Trypanosomatidae), the main causative agent of both zoonotic visceral leishmaniasis (VL) and canine leishmaniasis (CanL) in the Mediterranean basin. Eight species of sand flies have been previously recorded in Romania: Phlebotomus papatasi, Phlebotomus alexandri, Phlebotomus sergenti, Phlebotomus perfiliewi, Phlebotomus neglectus, Phlebotomus longiductus, Phlebotomus balcanicus and Sergentomyia minuta. Three of them (P. perfiliewi, P. neglectus and P. balcanicus) were incriminated as vectors of L. infantum. Recent reports of autochthonous CanL in Romania require updates on sand fly distribution and diversity in this country.
METHODS
Between 2013-2014 and 2016-2018, CDC light traps and mouth aspirators were used to collect sand flies in 132 locations from Romania, indoors and around various animal species shelters. Species identification of collected specimens was done using morphological keys, genetic tools and MALDI-TOF protein profiling.
RESULTS
Sand flies were present in seven localities (5.3%): Eibenthal, Baia Nouă, Gura Văii (south-western Romania, Mehedinţi County); Fundătura, Pâhneşti, Epureni (eastern Romania, Vaslui County); and Schitu (southern Romania, Giurgiu County). Of the total number of collected sand flies (n = 251), 209 (83.27%) were Phlebotomus neglectus, 39 (15.53%) P. perfiliewi, 1 (0.40%) P. papatasi, 1 (0.40%) P. balcanicus and 1 (0.40%) P. sergenti (sensu lato).
CONCLUSIONS
We confirmed the presence of five sand fly species previously recorded in Romania. However, their updated distribution differs from historical data. The diversity of sand fly species in Romania and their presence in areas with Mediterranean climatic influences constitutes a threat for the reemergence of vector-borne diseases. In the context of CanL and VL reemergence in Romania, but also due to imported cases of the diseases in both humans and dogs, updates on vector distribution are imperative.
Topics: Animal Distribution; Animals; Female; Genetic Variation; Insect Vectors; Male; Phlebotomus; Romania
PubMed: 31109351
DOI: 10.1186/s13071-019-3507-7 -
PloS One 2023To examine the genetic diversity of Leishmania major, 100 Giemsa-stained positive slides were collected from endemic foci of Iran (Northeast, Central, and Southwest...
To examine the genetic diversity of Leishmania major, 100 Giemsa-stained positive slides were collected from endemic foci of Iran (Northeast, Central, and Southwest provinces) over two consecutive years during 2019-2021. The Leishmania ITS-rDNA gene was amplified and Leishmania sp. was recognized by PCR-RFLP and sequencing. In addition, 178 registered ITS-rDNA sequences from other geographical regions of Iran were retrieved from GenBank, including different host species (human, sandfly and rodent). A total of 40 new haplotypes were discovered using the ITS-rDNA sequence analysis. IR29 (20.6%) and IR34 (61%) were the two most common haplotypes, represented by a star-like feature in the overall population. Analysis of the molecular variance test revealed low genetic diversity of L. major in human cases (Haplotype diversity; 0.341), rodent (Hd; 0.387) and sandfly (Hd; 0.390) sequences. The lowest genetic diversity of L. major was observed in Southwest/Southeast Iran (Hd: 0.104-0.286). The statistically Fst value indicated that L. major is not genetically differentiated between geographic regions of Iran, except for the Northeast-Southwest (Fst: 0.29055) and Central-Southwest (Fst: 0.30294) population pairs. The current study as the first investigation discloses new perspectives for further evaluation in the identification local transmission paradigms and initiating effective prevention strategies.
Topics: Humans; Animals; Leishmania major; Leishmaniasis, Cutaneous; Genetic Heterogeneity; Iran; Psychodidae; Phlebotomus; DNA, Ribosomal; Rodentia
PubMed: 37155684
DOI: 10.1371/journal.pone.0285520 -
TheScientificWorldJournal 2022An entomological survey was carried out in the locality of Aichoune to conduct a study on sand flies, species composition, and monthly relative abundance. This study is...
An entomological survey was carried out in the locality of Aichoune to conduct a study on sand flies, species composition, and monthly relative abundance. This study is essential for the implementation of integrated vector management control. Insects collection was carried out twice a month from January 2013 to December 2014 by means of adhesive and CDC-type light traps. A total of 5441 sand flies were collected with the predominance of males (a sex ratio = 1.89). The sampled specimens consist of seven species divided into two genera: (99.55%) and (0.44%). was the dominant species with an average annual proportion of 47.38%, followed by (37.32%), (8,56%), (6.23%), and (0.05%). The genus was less common (0.44%). was represented only by 0.36% and by 0.07%. The species dynamics showed a unimodal evolution for and . They were active from May to October. presents a trimodal trend showing the most relevant peak in August. The highest number of specimens was collected in June, when the temperature reaches an annual average value of 25.5°C. The obtained results will help us better understand the leishmaniasis transmission dynamics in the Aichoune locality and will contribute to the design of a surveillance strategy.
Topics: Animals; Female; Leishmaniasis, Cutaneous; Male; Morocco; Phlebotomus; Psychodidae; Temperature
PubMed: 36132438
DOI: 10.1155/2022/9382154 -
Viruses May 2021Sandfly-borne phleboviruses (phylum , realm , kingdom , genus ) comprise three genome segments of ribonucleic acid (RNA) and which encode an RNA-dependent RNA...
Sandfly-borne phleboviruses (phylum , realm , kingdom , genus ) comprise three genome segments of ribonucleic acid (RNA) and which encode an RNA-dependent RNA polymerase, which they use to transcribe the viral RNA genome into messenger RNA and to replicate the genome. At least some of these viruses cause mild 3-day fevers in humans but some also have been associated with more severe illnesses in humans. The 67 recognized phleboviruses are listed here in a table composed by the authors from International Committee on Taxonomy of Viruses reports as well as the scientific literature.
Topics: Animals; Genome, Viral; Phlebovirus; Phylogeny; Psychodidae; Reassortant Viruses
PubMed: 34063467
DOI: 10.3390/v13050918 -
Transboundary and Emerging Diseases Mar 2022Leishmania donovani is the causative agent of historically anthroponotic visceral leishmaniasis (VL) on the Indian subcontinent (ISC). L. donovani is transmitted by the... (Review)
Review
Leishmania donovani is the causative agent of historically anthroponotic visceral leishmaniasis (VL) on the Indian subcontinent (ISC). L. donovani is transmitted by the sand fly species Phlebotomus argentipes. Our collaborative group and others have shown that sand flies trapped outside in endemic villages have fed on cattle and dogs in addition to people. Domestic animals are reservoirs for L. donovani complex spp., particularly L. infantum, in other endemic areas. Multiple studies using quantitative PCR or serological detection methods have demonstrated that goats, cattle, rats and dogs were diagnostically positive for L. donovani infection or exposure in eastern Africa, Bangladesh, Nepal and India. There is a limited understanding of the extent to which L. donovani infection of domestic animals drives transmission to other animals or humans on the ISC. Evidence from other vector-borne disease elimination strategies indicated that emerging infections in domestic species hindered eradication. The predominant lesson learned from these other situations is that non-human reservoirs must be identified, controlled and/or prevented. Massive efforts are underway for VL elimination on the Indian subcontinent. Despite these herculean efforts, residual VL incidence persists. The spectre of an animal reservoir complicating elimination efforts haunts the final push towards full VL control. Better understanding of L. donovani transmission on the Indian subcontinent and rigorous consideration of how non-human reservoirs alter VL ecology are critical to sustain elimination goals.
Topics: Animals; Cattle; Cattle Diseases; Dog Diseases; Dogs; Humans; Leishmania donovani; Leishmaniasis, Visceral; Mammals; Phlebotomus; Psychodidae; Rats; Rodent Diseases
PubMed: 33686764
DOI: 10.1111/tbed.14061