Characterization of environmental drivers influencing the abundance of Anopheles maculipennis complex in Northern Italy
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ABSTRACT:
SUBMITTER: Gilioli G
PROVIDER: S-EPMC10916043 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:The correct identification of mosquito vectors is often hampered by the presence of morphologically indiscernible sibling species. The Maculipennis complex is one of these groups that include both malaria vectors of primary importance and species of low/negligible epidemiological relevance, of which distribution data in Italy are outdated. Our study was aimed at providing an updated distribution of Maculipennis complex in Northern Italy through the sampling and morphological/molecular identification of specimens from five regions. The most abundant species was Anopheles messeae (2032), followed by Anopheles maculipennis s.s. (418), Anopheles atroparvus (28) and Anopheles melanoon (13). Taking advantage of ITS2 barcoding, we were able to finely characterize tested mosquitoes, classifying all the Anopheles messeae specimens as Anopheles daciae, a taxon with debated rank to which we referred as species inquirenda (sp. inq.). The distribution of species was characterized by Ecological Niche Models (ENMs), fed by recorded points of presence. ENMs provided clues on the ecological preferences of the detected species, with An. daciae sp. inq. linked to stable breeding sites and An. maculipennis s.s. more associated to ephemeral breeding sites. We demonstrate that historical Anopheles malaria vectors are still present in Northern Italy.
| S-EPMC7979756 | biostudies-literature
Project description:Molecular identification (ITS2 barcoding) of the mosquitoes of the Maculipennis complex in northern Italy
| PRJEB41012 | ENA
Project description:BackgroundMembers of Anopheles maculipennis complex are effective malaria vectors in Europe and the Caspian Sea region in northern Iran, where malaria has been re-introduced since 1994. The current study has been designed in order to provide further evidence on the status of species composition and to identify more accurately the members of the maculipennis complex in northern Iran.MethodsThe second internal transcribed spacer of ribosomal DNA (rDNA-ITS2) was sequenced in 28 out of 235 specimens that were collected in the five provinces of East Azerbayjan, Ardebil, Guilan, Mazandaran and Khorassan in Iran.ResultsThe length of the ITS2 ranged from 283 to 302 bp with a GC content of 49.33-54.76%. No intra-specific variations were observed. Construction of phylogenetic tree based on the ITS2 sequence revealed that the six Iranian members of the maculipennis complex could be easily clustered into three groups: the An. atroparvus-Anopheles labranchiae group; the paraphyletic group of An. maculipennis, An. messeae, An. persiensis; and An. sacharovi as the third group.ConclusionDetection of three species of the An. maculipennis complex including An. atroparvus, An. messae and An. labranchiae, as shown as new records in northern Iran, is somehow alarming. A better understanding of the epidemiology of malaria on both sides of the Caspian Sea may be provided by applying the molecular techniques to the correct identification of species complexes, to the detection of Plasmodium composition in Anopheles vectors and to the status of insecticide resistance by looking to related genes.
| S-EPMC1784096 | biostudies-literature
Project description:BackgroundThe Anopheles dirus complex includes efficient malaria vectors of the Asian forested zone. Studies suggest ecological and biological differences between the species of the complex but variations within species suggest possible environmental influences. Behavioural variation might determine vector capacity and adaptation to changing environment. It is thus necessary to clarify the species distributions and the influences of environment on behavioural heterogeneity.MethodsA literature review highlights variation between species, influences of environmental drivers, and consequences on vector status and control. The localisation of collection sites from the literature and from a recent project (MALVECASIA) produces detailed species distributions maps. These facilitate species identification and analysis of environmental influences.ResultsThe maps give a good overview of species distributions. If species status partly explains behavioural heterogeneity, occurrence and vectorial status, some environmental drivers have at least the same importance. Those include rainfall, temperature, humidity, shade, soil type, water chemistry and moon phase. Most factors are probably constantly favourable in forest. Biological specificities, behaviour and high human-vector contact in the forest can explain the association of this complex with high malaria prevalence, multi-drug resistant Plasmodium falciparum and partial control failure of forest malaria in Southeast Asia.ConclusionEnvironmental and human factors seem better than species specificities at explaining behavioural heterogeneity. Although forest seems essential for mosquito survival, adaptations to orchards and wells have been recorded. Understanding the relationship between landscape components and mosquito population is a priority in foreseeing the influence of land-cover changes on malaria occurrence and in shaping control strategies for the future.
| S-EPMC1838916 | biostudies-literature
Project description:The Anopheles maculipennis complex consists of several mosquito species, including some primary malaria vectors. Therefore, the presence of a species in a particular area significantly affects public health. In this study, 1252 mosquitoes were collected in northern Italy, representing four identified species of the Anopheles maculipennis complex (Anopheles daciae sp. inq., Anopheles maculipennis s. s., Anopheles atroparvus and Anopheles melanoon). The sequences of two DNA markers, mitochondrial cytochrome c oxidase I (COI) and nuclear internal transcribed spacer 2 (ITS2), were generated. DNA-based species delimitation analyses were performed, incorporating public sequences, with distance-based and coalescent tree-based methods to confirm the actual species boundaries within the complex. While some morphospecies were unequivocally delimited by all methods and markers, COI analysis splitted An. maculipennis s. s. into two well-supported groups. However, molecular delimitation failed in recognizing An. daciae sp. inq. and An. messeae as two separate evolutionary entities. Species delimitation was further tested with a morphometric approach, which clearly differentiated species collected in the survey area. These findings underscore how challenging the characterization of the taxonomy of the complex is, providing evidence of potential introgression events in An. maculipennis s. s. and suggesting the need for robust evidence to support An. daciae sp. inq. and An. messeae as distinct species.
| S-EPMC11681070 | biostudies-literature
Project description:The present study aimed at identifying the members of the Anopheles maculipennis complex (Diptera: Culicidae) occurring in Belgium. Therefore, the second internal transcribed spacer of nuclear ribosomal DNA (ITS2) and the mitochondrial cytochrome oxidase subunit I (COI) loci were sequenced in 175 and 111 specimens, respectively, collected between 2007 and 2019. In parallel, the suitability of two species-diagnostic PCR-RFLP assays was tested. The identified specimens included: An. maculipennis s.s. (N = 105), An. daciae (N = 62), An. atroparvus (N = 6) and An. messeae (N = 2). Each species was characterized by unique ITS2 haplotypes, whereas COI only supported the monophyly of An. atroparvus, a historical malaria vector in Belgium. Species identification results were further supported by unique PCR-RFLP banding patterns. We report for the first time An. daciae in Belgium, where it was found to co-occur with An. maculipennis s.s. The latter was the most prevalent in the collection studied (60%) and appears to have the widest distribution in Belgium. As in other studies, An. daciae and An. messeae appeared the most closely related species, up to the point that their species status remains debatable, while their ecological differences, including vector competences, need further study.
| S-EPMC8453948 | biostudies-literature
Project description:BACKGROUND:Anopheles maculipennis complex, the historic vector of malaria, causes serious medical problems worldwide and exhibits different behaviours. Studying the odorant-binding proteins (OBPs), which influence the chemosensory system and behavioural responses, is essential to understanding the population structure and developing effective control measures against this vector. The present study was designed to identify and analyse the obp1 gene in An. maculipennis. METHODS:Adults of An. maculipennis sensu stricto were collected in Zanjan Province, northwest of Iran, and gDNAs of female mosquitoes were extracted. Fragments of An. maculipennis obp1 (Amacobp1) gene were amplified using degenerate and specific primers, and some of amplicons were selected for sequencing. RESULTS:Analysis of amplified products identified that the sequence of Amacobp1 gene was 1341 bp long. This gene contains three exons (5', internal, and 3'of 160, 256, and 18 bp, respectively) and encodes 144 amino acids. The sizes of introns I and II in deduced gene are 268 and 358 nucleotides, respectively. The amino acid sequence in the C-terminal of AmacOBP1 is similar to that of major malaria vector Anopheles species. However, its N-terminal has a specific signal peptide with 19 amino acids. This peptide is conserved in different studied populations, and its sequence of amino acids shows the most variation among anopheline species. CONCLUSIONS:Degenerate primers in this study are suggested for studying obp1 gene in Anopheles species. Amacobp1 gene is proposed as a molecular marker for the detection of intraspecific ecotypes and diagnosis of different species within Maculipennis Group. Moreover, the N-terminal of AmacOBP1 peptide is recommended as a molecular marker to identify the Amacobp1 expression patterns in different chemosensory organs for assessing the molecular mechanisms and developing novel behavioural disturbance agents to control An. maculipennis.
| S-EPMC6969430 | biostudies-literature
Project description:Factors responsible for the spatial and temporal clustering of Burkholderia pseudomallei in the environment remain to be elucidated. Whilst laboratory based experiments have been performed to analyse survival of the organism in various soil types, such approaches are strongly influenced by alterations to the soil micro ecology during soil sanitisation and translocation. During the monsoonal season in Townsville, Australia, B. pseudomallei is discharged from Castle Hill (an area with a very high soil prevalence of the organism) by groundwater seeps and is washed through a nearby area where intensive sampling in the dry season has been unable to detect the organism. We undertook environmental sampling and soil and plant characterisation in both areas to ascertain physiochemical and macro-floral differences between the two sites that may affect the prevalence of B. pseudomallei. In contrast to previous studies, the presence of B. pseudomallei was correlated with a low gravimetric water content and low nutrient availability (nitrogen and sulphur) and higher exchangeable potassium in soils favouring recovery. Relatively low levels of copper, iron and zinc favoured survival. The prevalence of the organism was found to be highest under the grasses Aristida sp. and Heteropogon contortus and to a lesser extent under Melinis repens. The findings of this study indicate that a greater variety of factors influence the endemicity of melioidosis than has previously been reported, and suggest that biogeographical boundaries to the organisms' distribution involve complex interactions.
| S-EPMC4580599 | biostudies-other
Project description:BackgroundMalaria is an important mosquito-borne disease, transmitted to humans by Anopheles mosquitoes. The aim of this study was to gather all records of three main malaria vectors in Iran during the last decades, and to predict the current distribution and the environmental suitability for these species across the country.MethodsAll published documents on An. superpictus Grassi (s.l.), An. maculipennis Meigen (s.l.) and An. sacharovi Favre during 1970-2016 in Iran were obtained from different online data bases and academic libraries. A database was created in ArcMap 10.3. Ecology of these species was analyzed and the ecological niches were predicted using MaxEnt model.ResultsAnopheles superpictus (s.l.) is the most widespread malaria vector in Iran, and exists in both malaria endemic and non-endemic areas. Whereas An. maculipennis (s.l.) is reported from the northern and northwestern parts, Anopheles sacharovi is mostly found in the northwestern Iran, although there are some reports of this species in the western, southwestern and eastern parts. The area under receiver operating characteristic (ROC) curve (AUC) for training and testing data was calculated as 0.869 and 0.828, 0.939 and 0.915, and 0.921 and 0.979, for An. superpictus (s.l.), An. maculipennis (s.l.) and An. sacharovi, respectively. Jackknife test showed the environmental variable with highest gain in the predicting power of the model when used in isolation was annual precipitation for An. superpictus (s.l.) and An. maculipennis (s.l.), and precipitation of the driest quarter for An. sacharovi.ConclusionsDespite this range, global warming may increase the potential risk for malaria transmission in some cleared-up areas, where these proven vectors are active. Mapping and prediction of spatial/temporal distribution of these vectors will be beneficial for decision makers to be aware of malaria transmission risk, especially in the western parts of the country.
| S-EPMC6029181 | biostudies-literature
Project description:BackgroundDetermining the host feeding patterns of mosquitoes by identifying the origin of their blood-meals is an important part of understanding the role of vector species in current and future disease transmission cycles. Collecting large numbers of blood-fed mosquitoes from the field is difficult, therefore it is important to maximise the information obtained from each specimen. This study aimed to use mosquito genome sequence to identify the species within Anopheles maculipennis sensu lato (An. maculipennis s.l.), identify the vertebrate hosts of field-caught blood-fed An. maculipennis s.l. , and to test for the presence of myxoma virus (Poxviridae, genus Leporipoxvirus) in specimens found to have fed on the European rabbit (Oryctolagus cuniculus).MethodsBlood-fed An. maculipennis s.l. were collected from resting sites at Elmley Nature Reserve, Kent, between June and September 2013. Hosts that An. maculipennis s.l. had fed on were determined by a PCR-sequencing approach based on the partial amplification of the mitochondrial cytochrome C oxidase subunit I gene. Mosquitoes were then identified to species by sequencing a region of the internal transcribed spacer-2. DNA extracts from all mosquitoes identified as having fed on rabbits were subsequently screened using PCR for the presence of myxoma virus.ResultsA total of 94 blood-fed Anopheles maculipennis s.l. were collected, of which 43 (46%) provided positive blood-meal identification results. Thirty-six of these specimens were identified as Anopheles atroparvus, which had fed on rabbit (n = 33, 92%) and cattle (n = 3, 8%). Seven mosquitoes were identified as Anopheles messeae, which had fed on cattle (n = 6, 86%) and dog (n = 1, 14%). Of the 33 An. atroparvus that contained rabbit blood, nine (27%) were positive for myxoma virus.ConclusionsResults demonstrate that a single DNA extract from a blood-fed mosquito can be successfully used for molecular identification of members of the An. maculipennis complex, blood-meal identification, and for the targeted detection of a myxoma virus. This study shows that An. atroparvus has a strong feeding preference for both healthy and myxoma-infected rabbits, providing evidence that this species may play a significant role in the transmission of myxomatosis among wild rabbit populations in the United Kingdom (UK).
| S-EPMC4536751 | biostudies-literature