Dataset Information

Phlebotomine sand flies in Southwest Germany: an update with records in new locations.

ABSTRACT:

Background

Vector-borne diseases (VBD) are of growing global importance. Sand flies are potential vectors for phleboviruses (family Phenuiviridae) including Toscana virus (TOSV), Sicilian virus, Sandfly fever, Naples virus, and Leishmania parasites in Europe. To date, only two phlebotomine species have been recorded for Germany: Phlebotomus perniciosus and Phlebotomus mascittii. This study updates the distribution and abundance of the two occurring species.

Methods

An entomological field study was carried out during 2015-2018 to assess the abundance of sand flies in Southwest Germany within the federal states Baden-Wuerttemberg (BW) and Rhineland-Palatinate (RLP). A total of 176 collection sites were examined using CDC light traps.

Results

A total of 149 individuals of P. mascittii were collected. During 2015-2018, P. mascittii was found at all sites known positive from previous studies and was detected at 15 additional sites previously unknown for the presence of sand flies. Although the environment has changed considerably in 30 years, no significant difference in sand fly dynamics and distribution was found. Phlebotomus perniciosus has only been trapped once since 2001.

Conclusions

This study showed that sand flies occur in different areas in Southern Germany where they had not been recorded previously. Therefore, it can be assumed that they are more widespread than expected. In addition, sand flies could be found over several years at the same trapping sites, indicating population stability. This supports the need for continued surveillance of possible vector populations and urgent clarification of the vector competence of P. mascittii.

SUBMITTER: Oerther S

PROVIDER: S-EPMC7171781 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Phlebotomine sand flies in Southwest Germany: an update with records in new locations.

Oerther Sandra S Jöst Hanna H Heitmann Anna A Lühken Renke R Krüger Andreas A Steinhausen Irmgard I Brinker Christine C Lorentz Susanne S Marx Michael M Schmidt-Chanasit Jonas J Naucke Torsten T Becker Norbert N

Parasites & vectors 20200421 1

<h4>Background</h4>Vector-borne diseases (VBD) are of growing global importance. Sand flies are potential vectors for phleboviruses (family Phenuiviridae) including Toscana virus (TOSV), Sicilian virus, Sandfly fever, Naples virus, and Leishmania parasites in Europe. To date, only two phlebotomine species have been recorded for Germany: Phlebotomus perniciosus and Phlebotomus mascittii. This study updates the distribution and abundance of the two occurring species.<h4>Methods</h4>An entomologica ...[more]

PMID: 32312300

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Project description: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.

Project description:BackgroundRecent climate and environmental changes have resulted in the geographical expansion of Mediterranean Leishmania infantum vectors towards northern latitudes and higher altitudes in different European countries, including Italy, where new foci of canine leishmaniasis have been observed in the northern part of the country. Northern Italy is also an endemic area for mosquito-borne diseases. During entomological surveillance for West Nile virus, mosquitoes and other hematophagous insects were collected, including Phlebotomine sand flies. In this study, we report the results of Phlebotomine sand fly identification during the entomological surveillance conducted from 2017 to 2019.MethodsThe northeastern plain of Italy was divided by a grid with a length of 15 km, and a CO2-CDC trap was placed in each geographical unit. The traps were placed ~ 15 km apart. For each sampling site, geographical coordinates were recorded. The traps were operated every two weeks, from May to November. Sand flies collected by CO2-CDC traps were identified by morphological and molecular analysis.ResultsFrom 2017 to 2019, a total of 303 sand flies belonging to the species Phlebotomus perniciosus (n = 273), Sergentomyia minuta (n = 5), P. mascittii (n = 2) and P. perfiliewi (n = 2) were collected, along with 21 unidentified specimens. The trend for P. perniciosus collected during the entomological surveillance showed two peaks, one in July and a smaller one in September. Sand flies were collected at different altitudes, from -2 m above sea level (a.s.l.) to 145 m a.s.l. No correlation was observed between altitude and sand fly abundance.ConclusionsFour Phlebotomine sand fly species are reported for the first time from the northeastern plain of Italy. Except for S. minuta, the sand fly species are competent vectors of Leishmania parasites and other arboviruses in the Mediterranean Basin. These findings demonstrate the ability of sand flies to colonize new environments previously considered unsuitable for these insects. Even though the density of the Phlebotomine sand fly population in the plain areas is consistently lower than that observed in hilly and low mountainous areas, the presence of these vectors could herald the onset of epidemic outbreaks of leishmaniasis and other arthropod-borne diseases in areas previously considered non-endemic.

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Project description:Lutzomyia longipalpis are vectors of medically important visceral leishmaniasis in South America. Blood-fed adult females digest large amounts of protein, and xanthine dehydrogenase is thought to be a key enzyme involved in protein catabolism through the production of urate. Large amounts of heme are also released during digestion with potentially damaging consequences, as heme can generate oxygen radicals that damage lipids, proteins and nucleic acids. However, urate is an antioxidant that may prevent such oxidative damage produced by heme. We investigated xanthine dehydrogenase by developing the RNAi technique for sand flies and used this technique to knock down the Lu. longipalpis xanthine dehydrogenase gene to evaluate its role in survival of adult females after blood feeding. The gene sequence of Lu. longipalpis xanthine dehydrogenase is described together with expression in different life cycle stages and RNAi knock down. Semi-quantitative RT-PCR of xanthine dehydrogenase expression showed a significant increase in expression after bloodmeal ingestion. Microinjection of dsRNA via the thorax of 1-day-old adult female sand flies resulted in approximately 40% reduction of xanthine dehydrogenase gene expression in comparison to flies injected with a control dsRNA. A significant reduction of urate in the whole body and excretions of Lu. longipalpis was observed after dsRNA xanthine dehydrogenase microinjection and feeding 96h later on rabbit blood. Sand flies injected with XDH dsRNA also exhibit significantly reduced life span in comparison with the mock-injected group when fed on sucrose or when rabbit blood fed, showing that urate could be indeed an important free radical scavenger in Lu. longipalpis. The demonstration of xanthine dehydrogenase knock down by dsRNA microinjection, low mortality of microinjected insects and the successful bloodfeeding of injected insects demonstrated the utility of RNAi as a tool for functional analysis of genes in phlebotomine sand flies.

Project description:BACKGROUND:Phlebotomine sand flies (Diptera: Psychodidae) are vectors of Leishmania spp., protozoan parasites responsible for a group of neglected diseases called leishmaniases. Two sand fly genera, Phlebotomus and Sergentomyia, contain species that are present in the Mediterranean islands of Crete and Cyprus where the visceral (VL), cutaneous (CL) and canine (CanLei) leishmaniases are a public health concern. The risk of transmission of different Leishmania species can be studied in an area by monitoring their vectors. Sand fly species are traditionally identified using morphological characteristics but minute differences between individuals or populations could be overlooked leading to wrong epidemiological predictions. Molecular identification of these important vectors has become, therefore, an essential tool for research tasks concerning their geographical distribution which directly relates to leishmaniasis control efforts. DNA barcoding is a widely used molecular identification method for cataloguing animal species by sequencing a fragment of the mitochondrial gene encoding cytochrome oxidase I. RESULTS:DNA barcoding was used to identify individuals of five sand fly species (Phlebotomus papatasi, P. similis, P. killicki, Sergentomyia minuta, S. dentata) circulating in the islands of Crete and Cyprus during the years 2011-2014. Phlebotomus papatasi is a known vector of zoonotic CL in the Middle East and it is found in both islands. Phlebotomus similis is the suspected vector of Leishmania tropica in Greece causing anthroponotic CL. Phlebotomus killicki was collected in Cyprus for the first time. Sergentomyia minuta, found to present intraspecific diversity, is discussed for its potential as a Leishmania vector. Molecular identification was consistent with the morphological identification. It successfully identified males and females, which is difficult when using only morphological characters. A phylogenetic tree was constructed based on the barcodes acquired, representing their genetic relationships along with other species from the area studied. All individuals identified were clustered according to their species and subgenus. CONCLUSIONS:Molecular identification of sand flies via DNA barcoding can accurately identify these medically important insects assisting traditional morphological tools, thus helping to assess their implication in Leishmania transmission.

Dataset Information

Phlebotomine sand flies in Southwest Germany: an update with records in new locations.

Background

Methods

Results

Conclusions

Publications

Phlebotomine sand flies in Southwest Germany: an update with records in new locations.

Similar Datasets

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