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PLoS Neglected Tropical Diseases Jan 2022Phlebotomine sand flies (Diptera: Psychodidae) are important vectors of various human and animal pathogens such as Bartonella bacilliformis, Phlebovirus, and parasitic...
BACKGROUND
Phlebotomine sand flies (Diptera: Psychodidae) are important vectors of various human and animal pathogens such as Bartonella bacilliformis, Phlebovirus, and parasitic protozoa of the genus Leishmania, causative agent of leishmaniases that account among most significant vector-borne diseases. The Maghreb countries Mauritania, Morocco, Algeria, Tunisia, and Libya occupy a vast area of North Africa and belong to most affected regions by these diseases. Locally varying climatic and ecological conditions support diverse sand fly fauna that includes many proven or suspected vectors. The aim of this review is to summarize often fragmented information and to provide an updated list of sand fly species of the Maghreb region with illustration of species-specific morphological features and maps of their reported distribution.
MATERIALS AND METHODS
The literature search focused on scholar databases to review information on the sand fly species distribution and their role in the disease transmissions in Mauritania, Morocco, Algeria, Tunisia, and Libya, surveying sources from the period between 1900 and 2020. Reported distribution of each species was collated using Google Earth, and distribution maps were drawn using ArcGIS software. Morphological illustrations were compiled from various published sources.
RESULTS AND CONCLUSIONS
In total, 32 species of the genera Phlebotomus (Ph.) and Sergentomyia (Se.) were reported in the Maghreb region (15 from Libya, 18 from Tunisia, 23 from Morocco, 24 from Algeria, and 9 from Mauritania). Phlebotomus mariae and Se. africana subsp. asiatica were recorded only in Morocco, Ph. mascitti, Se. hirtus, and Se. tiberiadis only in Algeria, whereas Ph. duboscqi, Se. dubia, Se. africana africana, Se. lesleyae, Se. magna, and Se. freetownensis were reported only from Mauritania. Our review has updated and summarized the geographic distribution of 26 species reported so far in Morocco, Algeria, Tunisia, and Libya, excluding Mauritania from a detailed analysis due to the unavailability of accurate distribution data. In addition, morphological differences important for species identification are summarized with particular attention to closely related species such as Ph. papatasi and Ph. bergeroti, Ph. chabaudi, and Ph. riouxi, and Se. christophersi and Se. clydei.
Topics: Africa, Northern; Animals; Communicable Diseases; Humans; Insect Vectors; Psychodidae
PubMed: 34990451
DOI: 10.1371/journal.pntd.0009952 -
Parasites & Vectors Oct 2022Phlebotomine sand flies are proven or suspected vectors of several pathogens of importance, including leishmaniasis, bartonellosis and sand fly fevers. Although sand...
Phlebotomine sand flies are proven or suspected vectors of several pathogens of importance, including leishmaniasis, bartonellosis and sand fly fevers. Although sand flies have a worldwide distribution, there has been limited research published on sand flies and sand fly-borne pathogens throughout the Greater Mekong Sub-region (GMS). This review followed the PRISMA guidelines to determine the biodiversity and presence of phlebotomine sand flies and their associated pathogens in the GMS, specifically Cambodia, Thailand, the Lao People's Democratic Republic (Laos), Malaysia and Vietnam. A total of 1472 records were identified by searching electronic databases, scanning reference lists of articles and consulting experts in the field. After screening of title and abstracts, 178 records remained and were further screened for original data (n = 34), not having regional data (n = 14), duplication of data (n = 4), records not available (n = 4) and no language translation available (n = 2). A total of 120 studies were then included for full review, with 41 studies on sand fly-related disease in humans, 33 studies on sand fly-related disease in animals and 54 entomological studies focused on sand flies (5 papers contained data on > 1 category), with a majority of the overall data from Thailand. There were relatively few studies on each country, with the exception of Thailand, and the studies applied different methods to investigate sand flies and sand fly-borne diseases, impacting the ability to conduct meaningful meta-analysis. The findings suggest that leishmaniasis in humans and the presence of sand fly vectors have been reported across several GMS countries over the past 100 years, with local transmission in humans confirmed in Thailand and Vietnam. Additionally, local Mundinia species are likely transmitted by biting midges. Findings from this study provide a framework for future investigations to determine the geographic distribution and risk profiles of leishmaniasis and other associated sand fly-borne disease throughout the GMS. It is recommended that researchers expand surveillance efforts across the GMS, with an emphasis placed on entomological surveys, syndromic and asymptomatic monitoring in both humans and animals and molecular characterization of sand flies and sand fly-borne pathogens, particularly in the understudied countries of Cambodia, Vietnam and Laos.
Topics: Animals; Humans; Insect Vectors; Leishmania; Leishmaniasis; Phlebotomus; Psychodidae
PubMed: 36199150
DOI: 10.1186/s13071-022-05464-8 -
PLoS Neglected Tropical Diseases Dec 2022Phlebotomus (Paraphlebotomus) sergenti is a widespread proven vector of Leishmania pathogens causing anthroponotic cutaneous leishmaniasis (ACL), due to L. tropica, in...
BACKGROUND
Phlebotomus (Paraphlebotomus) sergenti is a widespread proven vector of Leishmania pathogens causing anthroponotic cutaneous leishmaniasis (ACL), due to L. tropica, in the old world. The activity of P. (Par.) sergenti is seasonal and sensitive to general variations in climate. Phenological data sets can thus provide a baseline for continuing investigations on P. (Par.) sergenti population dynamics that may impact future leishmaniasis transmission and control scenarios.
METHODS/PRINCIPAL FINDING
A systematic review of the seasonality of P. (Par.) sergenti was undertaken globally. Six hundred eight scientific papers were identified, and data were extracted from 35 ones, with informative data on sand fly seasonal dynamics on trapping performed from 1992 to December 2021 on 63 sites from 12 countries. Morocco, Saudi Arabia, Iraq, Iran, Pakistan, Palestine, Turkey, Spain, Portugal, Italy, Cyprus, and Georgia. The data extracted from the literature survey were further normalized. Our analysis recorded that the highest P.(Par.) sergenti activity occurs during the hot and dry seasons, primarily in July and August, whatever the location studied. We noticed a relationship between the latitude of sites and sand fly presence (from early April to June) and the type of density trend, varying from a single peak to multiple peaks. On a geographical scale, P. (Par.) sergenti concentrates between 32-37° in latitude in a large interval following the longitude and the highest number of sites with high P. (Par.) sergenti activity is located at the latitude 32°. We also quoted a similar seasonal dynamic and geographic distribution with Phlebotomus (Phlebotomus) papatasi, a proven vector of L. major that causes cutaneous infection. No apparent risk for ACL occurred from December to March, at least in the years and geographic areas considered in this survey. Altogether, knowing that high P. (Par.) sergenti activity would be linked with an increased risk of leishmaniasis transmission, and our study provides information that can be used for control programs on ACL transmission.
CONCLUSIONS
Despite variations, we found a relatively homogeneous pattern of P. (Par.) sergenti potential behavior in sites whose data are published. A higher risk for L. tropica transmission was identified in the June-October period. Still, such risk was not equally distributed throughout the area since density waves of adults occurred earlier and were more frequent in some territories, like Saudi Arabia.
Topics: Animals; Phlebotomus; Seasons; Psychodidae; Leishmaniasis, Cutaneous; Morocco; Leishmania tropica
PubMed: 36469546
DOI: 10.1371/journal.pntd.0010886 -
PLoS Neglected Tropical Diseases Mar 2022Visceral leishmaniasis (VL) has been targeted for elimination from Southeast Asia (SEA). The disease has been endemic in SEA, and in other parts of the world involving...
Visceral leishmaniasis (VL) has been targeted for elimination from Southeast Asia (SEA). The disease has been endemic in SEA, and in other parts of the world involving both humans and animals. One of the key strategies for combating VL is controlling for the vector sandfly. There are a few vector control strategies that are currently in practice. We sought to assess the efficacy and community effectiveness of insecticide treated nets (ITNs) in controlling the burden of sandfly and the occurrence of VL among humans. We conducted a systematic review following a study protocol and the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria. 6331 initial hits were retrieved from Google Scholar, Lilacs, PubMed, Science Direct, WHOlis, WHOiris and PAHOiris. 25 met the full inclusion criteria. Findings show that the insecticide impregnated bednets and the commercially treated long lasting insecticidal nets (LLINs) are effective in controlling sandflies, with mortalities as high as 75% lasting over a year; although their role in controlling VL in the community was not extensively studied, since effectiveness was usually measured with sandflies densities. Findings also show that insecticide impregnated bednets are low cost and well accepted in the community, however, early erosion of insecticides from nets could occur. Some studies also showed that killing of sandflies may not translate into reduction of VL, therefore sandfly knock down and killing data needs to be interpreted with caution. Conclusions of this review are (1) combining insecticide impregnated bednets, as targeted interventions, with another vector control measure, particularly indoor residual spraying, and in conjunction with case detection, could be the way forward to controlling VL in resource limited settings. (2) Given the current low incidence of VL in SEA, it can be difficult to further research the community effectiveness of those control measures in reducing VL.
Topics: Animals; Insect Control; Insecticide-Treated Bednets; Insecticides; Leishmaniasis, Visceral; Mosquito Control; Phlebotomus; Psychodidae
PubMed: 35235556
DOI: 10.1371/journal.pntd.0010196 -
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 -
Parasites & Vectors Nov 2022
PubMed: 36397153
DOI: 10.1186/s13071-022-05550-x -
PLoS Neglected Tropical Diseases Mar 2024Human myiasis is a parasitic dipteran fly infestation that infects humans and vertebrates worldwide. However, the disease is endemic in Sub-Saharan Africa and Latin...
BACKGROUND
Human myiasis is a parasitic dipteran fly infestation that infects humans and vertebrates worldwide. However, the disease is endemic in Sub-Saharan Africa and Latin America. In Sub-Saharan Africa, it is under-reported and therefore its prevalence is unknown. This systematic review aims to elucidate the prevalence of human myiasis, factors that influence the infection, and myiasis-causing fly species in SSA. The review also dwelled on the common myiasis types and treatment methods of human myiasis.
METHODS
Here, we collect cases of human myiasis in Sub-Saharan Africa based on literature retrieved from PubMed, Google Scholar and Science Direct from 1959 to 2022. A total of 75 articles and 157 cases were included in the study. The recommendations of PRISMA 2020 were used for the realization of this systematic review.
RESULTS
In total, 157 cases of human myiasis in SSA were reviewed. Eleven fly species (Cordylobia anthropophaga, Cordylobia rodhaini, Dermatobia hominis, Lucilia cuprina, Lucilia sericata, Oestrus ovis, Sarcophaga spp., Sarcophaga nodosa, Chrysomya megacephala, Chrysomya chloropyga and Clogmia albipuntum) were found to cause human myiasis in SSA. Cordylobia anthropophaga was the most prevalent myiasis-causing species of the reported cases (n = 104, 66.2%). More than half of the reported cases were from travelers returning from SSA (n = 122, 77.7%). Cutaneous myiasis was the most common clinical presentation of the disease (n = 86, 54.7%). Females were more infected (n = 78, 49.6%) than males, and there was a higher infestation in adults than young children.
CONCLUSION
The findings of this study reveals that international travelers to Sub-Saharan Africa were mostly infested therefore, we recommend that both international travelers and natives of SSA be enlightened by public health officers about the disease and its risk factors at entry points in SSA and the community level respectively. Clinicians in Sub-Saharan Africa often misdiagnose the disease and most of them lack the expertise to properly identify larvae, so we recommend the extensive use of molecular identification methods instead.
Topics: Male; Adult; Animals; Female; Child; Humans; Child, Preschool; Diptera; Myiasis; Larva; Psychodidae; Africa South of the Sahara; Calliphoridae
PubMed: 38547087
DOI: 10.1371/journal.pntd.0012027 -
PLoS Neglected Tropical Diseases May 2020Local anomalies in rainfall and temperature induced by El Niño and La Niña episodes could change the structure of the vector community. We aimed to estimate the effect...
Local anomalies in rainfall and temperature induced by El Niño and La Niña episodes could change the structure of the vector community. We aimed to estimate the effect of the El Niño-La Niña cycle in the potential distribution of cutaneous leishmaniasis (CL) vector species in Colombia and to compare the richness of the vectors with the occurrence of CL in the state of Norte de Santander. The potential distributions of four species were modeled using a MaxEnt algorithm for the following episodes: La Niña 2010-2011, Neutral 2012-2015 and El Niño 2015-2016. The relationship between the potential richness of the vectors and the occurrence of CL in Norte de Santander was evaluated with a log-binomial regression model. During the El Niño 2015-2016 episode, Lutzomyia ovallesi and Lutzomyia panamensis increased their distribution into environmentally suitable areas, and three vector species (Lutzomyia gomezi, Lutzomyia ovallesi and Lutzomyia panamensis) showed increases in the range of their altitudinal distribution. During the La Niña 2010-2011 episode, a reduction was observed in the area suitable for occupation by Lutzomyia gomezi and Lutzomyia spinicrassa. During the El Niño 2015-2016 episode, the occurrence of at least one CL case was related to a higher percentage of rural localities showing a richness of vectors = 4. The anomalies in rainfall and temperature induced by the episodes produced changes in the potential distribution of CL vectors in Colombia. In Norte de Santander, during Neutral 2012-2015 and El Niño 2015-2016 episodes, a higher probability of at least one CL case was related to a higher percentage of areas with a greater richness of vectors. The results help clarify the effect of the El Niño-La Niña cycle in the dynamics of CL in Colombia and emphasize the need to monitor climate variability to improve the prediction of new cases.
Topics: Animals; Colombia; El Nino-Southern Oscillation; Humans; Insect Vectors; Leishmaniasis, Cutaneous; Psychodidae
PubMed: 32463829
DOI: 10.1371/journal.pntd.0008324