Ochlerotatus Caspius Research Articles

Habitat suitability modeling of mosquito species in Faiyum Governorate, Egypt, using GIS

BackgroundThe life cycle and geographic range of mosquitoes are profoundly influenced by weather conditions. In Faiyum Governorate, Egypt, researchers looked at over 42 different mosquito breeding areas in the wild. Culex pipiens, Culex antennatus, Culex perexiguus, Culex theileri, Anopheles multicolor, Anopheles sergentii, Ochlerotatus caspius, Culiseta longiareolata, and Uranotaenia unguiculata, were all represented among the collected mosquito larvae. Using Maxent, we identified the most important bioclimatic factors affecting habitat appropriateness for each species. In order to determine the link between a species’ habitat appropriateness and bioclimatic factors, the computer builds response curves for each bioclimatic factor. All species risk maps, species richness maps, and individual species maps were generated with a Software that build interactive web maps (ArcGIS 10.3).ResultsEach mosquito species’ range was impacted by four bioclimatic factors. The most influential factors were those linked to temperature and precipitation. Culex antennatus, Culex perexiguus, Culex pipiens, and Ochlerotatus caspius responded best to temperature-related factors. Precipitation of wettest month (bio 13) was effective in four species (Anopheles multicolor, Culex antennatus, Culex perexiguus, and Culex pipiens).ConclusionAreas in the north and west of El-Fayoum district (Zawyat El-Karadsah, Beni-Saleh, and Monshat Abd-Allah), in Tamiya in Kafr Mahfouz, in the south of Abshway, especially in Tobhar, in the north of Atssa, in the south and center of Sinnuris have been identified as high-risk areas and more susceptible to mosquito-borne diseases.

Modeling the effects of species associations and abiotic parameters on the abundance of mosquito species in a Mediterranean wetland

Recent outbreaks of the West Nile virus have been reported in southern Spain, a region with important wetland habitats for migratory birds. Here, we analyzed the role of species association and abiotic parameters on the abundance of seven mosquito species in the Doñana National Park, Spain. We applied the Joint Species Distribution Models (JSDM), using the Hierarchical Modeling of Species Communities approach to simultaneously model the effect of habitat type, normalized difference vegetation index, hydroperiod, distance to rivers, land surface temperature, and the abundance of seven mosquito species. We created three models with varied parameters and evaluated the effects of abiotic parameters and species-to-species associations, which served as proxies for species interactions. Our models estimated the species-specific responses of the mosquito community to abiotic parameters. A positive association was identified within the Culex community with potential biotic interactions. However, Ochlerotatus caspius, Ochlerotatus detritus, and Anopheles atroparvus had no statistically significant association with each other and with the Culex species after accounting for the effect of abiotic parameters. We also found that the potential species associations estimated at particular sites and abiotic parameters influenced the model projection for the average abundance of mosquito species. The JSDM will allow spatial projection of the abundance of each mosquito species, which is an important parameter for epidemiological models. The JSDM inference of species association is important because predation, competition, and facilitation affect the distribution and abundance of different species.

Mosquito abundance and physicochemical characteristics of their breeding water in El-Fayoum Governorate, Egypt

ObjectivesThis study was conducted to identify the mosquito species and the physicochemical characteristics of their breeding sites in six districts in El-Fayoum Governorate, Egypt, during October and November 2020. MethodsUsing the dipping method, mosquito larvae were collected from forty-two different breeding sites, including irrigation channels, canals, agricultural puddles, sewage tanks, stagnant water puddles, and swamps. Water temperature, pH, alkalinity, nitrite, chloride, electrical conductivity (EC), and total dissolved solids (TDS) were measured for all the studied breeding sites. ResultsThe survey revealed the presence of nine mosquito species: Culex perexiguus (Theobald, 1901), Culex pipiens (Linnaeus, 1758), Culex antennatus (Becker, 1903), Culex theileri (Theobald, 1903), Anopheles multicolor (Cambouliu, 1902), Anopheles sergentii (Theobald, 1907), Ochlerotatus caspius (Pallas, 1771), Culiseta longiareolata (Macquart, 1838), and Uranotaenia ungiculata (Edwards, 1913), representing five genera. Out of these species, Cx. pipiens is the most abundant. Oc. caspius and Cx. antennatus revealed significant positive correlations with chloride, TDS, and EC. Cx. perexiguus only showed significant positive correlations with chloride. ConclusionMost of the recorded mosquito species are found to be able to tolerate different degrees of pollution in their breeding water. These data may contribute to establishing a database on mosquito vectors and their habitats and, hence, assist in planning and implementing the appropriate control measures in this region.

First description of the mitogenome and phylogeny:Aedes vexansand Ochlerotatus caspius of the Tribe Aedini (Diptera: Culicidae)

Culicidae, the mosquito family, includes more than 3600 species subdivided into the subfamilies Anophelinae and Culicinae. One-third of mosquitoes belong to the Aedini tribe, which is subordinate to the subfamily Culicinae, which comprises common vectors of viral zoonoses. The tribe of Aedini is extremely diverse in morphology and geographical distribution and has high ecological and medical significance. However, knowledge about the systematics of the Aedini tribe is still limited owing to its large population and the similar morphological characteristics of its species. This study provides the first description of the complete mitochondrial (mt) genome sequence of Aedes vexans and Ochlerotatus caspius belonging to the Aedini tribe. The mt genomes of A. vexans and O. caspius are circular molecules that are 15,861bp and 15,954bp in size, with AT contents of 78.54% and 79.36%, respectively. Both the circular mt genomes comprise 37 functional subunits, including 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes (tRNAs), and a control region (also known as the AT-rich region). The most common start codons are ATT/ATG, apart from cox1 (TCG) and nad5 (GTG), while TAA is the termination codon for all PCGs. All tRNAs have a typical clover leaf structure, except tRNA Ser1. Phylogenetic analysis of the concatenated, aligned amino acid sequences of the 13 PCGs showed that A. vexans gathered with Aedes sp. in a sister taxon, and O. caspius gathered with Ochlerotatus sp. in a sister taxon. The findings from the present study support the concept of monophyly of all groups, ratify the current taxonomic classification, and provide vital molecular marker resources for further studies of the taxonomy, population genetics, and systematics of the Aedini tribe.

Toxicological and biochemical studies for chlorpyrifos insecticide on some mosquito larvae and their associated predators

ABSTRACT Use of chemical insecticide with natural enemies could be more effective in mosquito control strategy. This study examined the toxicity of chlorpyrifos insecticide against three field-collected mosquito species, Culex pipiens, Anopheles pharoensis and Ochlerotatus caspius and their associated predators dragonfly (Pantala flavescens) and mayfly (Caenis stephens) naiads as non- target insect for chlorpyrifos. The predation potential of Pa. flavescens and Ca. stephens against tested mosquito larvae was also investigated. Additional biochemical assays were carried out to detect the effect of chlorpyrifos on some detoxifying enzymes of tested mosquito larvae and their associated predators. The results showed that (Pa. flavescens) have higher predation potential than (Ca. stephens). The toxicological results recorded high toxic effect of chlorpyrifos on Ca. stephens followed by An. pharoensis and Oc. caspius with percent mortality 100, 90 and 85% respectively, while Pa. flavescens exhibited high resistance followed by Cx. pipiens with percent mortality 20 and 40% respectively. Moreover, Acetylcholinesterase and glutathione S-transferase were significantly increased only in Cx. pipiens and Pa. flavescens. It could be concluded that, chlorpyrifos have different toxicological effect on the tested mosquito larvae and associated predators. So, the side effect of chlorpyrifos must be taken in consideration before using it in control programs.

Comparative efficacy of BG-Sentinel 2 and CDC-like mosquito traps for monitoring potential malaria vectors in Europe

BackgroundDifferent trapping devices and attractants are used in the mosquito surveillance programs currently running in Europe. Most of these devices target vector species belonging to the genera Culex or Aedes, and no studies have yet evaluated the effectiveness of different trapping devices for the specific targeting of Anopheles mosquito species, which are potential vectors of malaria in Europe. This study aims to fill this gap in knowledge by comparing the performance of trapping methods that are commonly used in European mosquito surveillance programs for Culex and Aedes for the specific collection of adults of species of the Anopheles maculipennis complex.MethodsThe following combinations of traps and attractants were used: (i) BG-Sentinel 2 (BG trap) baited with a BG-Lure cartridge (BG + lure), (ii) BG trap baited with a BG-Lure cartridge and CO2 (BG + lure + CO2), (iii) Centers for Disease Control and Prevention-like trap (CDC trap) baited with CO2 (CDC + CO2), (iv) CDC trap used with light and baited with BG-Lure and CO2 (CDC light + lure + CO2). These combinations were compared in the field using a 4 × 4 Latin square study design. The trial was conducted in two sites in northeastern Italy in 2019. Anopheles species were identified morphologically and a sub-sample of An. maculipennis complex specimens were identified to species level by molecular analysis.ResultsForty-eight collections were performed on 12 different trapping days at each site, and a total of 1721 An. maculipennis complex specimens were captured. The molecular analysis of a sub-sample comprising 254 specimens identified both Anopheles messeae/Anopheles daciae (n = 103) and Anopheles maculipennis sensu stricto (n = 8) at site 1, while at site 2 only An. messeae/An. daciae (n = 143) was found. The four trapping devices differed with respect to the number of An. messeae/An. daciae captured. More mosquitoes were caught by the BG trap when it was used with additional lures (i.e. BG + lure + CO2) than without the attractant, CO2 [ratioBG+lure vs BG+lure+CO2 = 0.206, 95% confidence interval (CI) 0.101–0.420, P < 0.0001], while no significant differences were observed between CDC + CO2 and CDC light + lure + CO2 (P = 0.321). The addition of CO2 to BG + lure increased the ability of this combination to capture An. messeae/An. daciae by a factor of 4.85, and it also trapped more mosquitoes of other, non-target species (Culex pipiens, ratioBG+lure vs BG+lure+CO2 = 0.119, 95% CI 0.056–0.250, P < 0.0001; Ochlerotatus caspius, ratioBG+lure vs BG+lure+CO2 = 0.035, 95% CI 0.015–0.080, P < 0.0001).ConclusionsOur results show that both the BG-Sentinel and CDC trap can be used to effectively sample An. messeae/An. daciae, but that the combination of the BG-Sentinel trap with the BG-Lure and CO2 was the most effective means of achieving this. BG + lure + CO2 is considered the best combination for the routine monitoring of host-seeking An. maculipennis complex species such as An. messeae/An. daciae. The BG-Sentinel and CDC traps have value as alternative methods to human landing catches and manual aspiration for the standardized monitoring of Anopheles species in Europe.Graphical abstract

Dirofilaria immitis and Dirofilaria repens in mosquitoes from Corsica Island, France

BackgroundDirofilaria immitis and Dirofilaria repens are the main causative agents of heartworm disease and subcutaneous dirofilariasis in domestic and wild canids, respectively. Both pathogens have zoonotic potential and are transmitted by mosquitoes. The present study aimed to determine the transmission period, prevalence and diversity of Dirofilaria spp. vectors from endemic areas of Corsica (France).MethodsA monthly point data model based on average temperature recorded by four meteorological stations during 2017 was used to calculate the Dirofilaria transmission period. From June to September 2017, female mosquitoes (n = 1802) were captured using Biogents® Sentinel 2 traps lured with carbon dioxide and BG-Lure™ or octanol. Mosquitoes were identified to species level, pooled accordingly, and screened using multiplex real-time qPCR to detect D. immitis and D. repens.ResultsThe monthly point data model showed the possible transmission of Dirofilaria spp. from the third week in May to the last week in October in the studied area. Mosquitoes were identified as Ochlerotatus caspius (n = 1432), Aedes albopictus (n = 199), Culex pipiens sensu lato (n = 165) and Aedes vexans (n = 6) and were grouped into 109 pools (from 1 to 27 specimens, mean 11.4 ± 0.7), of which 16 scored positive for Dirofilaria spp. (i.e., n = 13; estimated infection rate [EIR] = 1.1% for D. immitis and n = 3; EIR = 0.2% for D. repens). Specifically, 6 (i.e., EIR = 3.8%) of 15 pools of Ae. albopictus were positive for D. immitis, 2 of 14 of Cx. pipiens s.l. were positive for D. immitis and D. repens, respectively, and 8 of 77 pools of Oc. caspius were positive for D. immitis (i.e., n = 6; EIR = 0.4%) and D. repens (i.e., 2; EIR = 0.1%). The highest mosquito infection rate was recorded in July (EIR = 2.5%), then in June (EIR = 1.3%) and September (EIR = 0.6%).ConclusionsThe data suggest that both Dirofilaria species are endemic and occur possibly in sympatry in the studied area in Corsica, highlighting the need to implement preventive chemoprophylaxis and vector control strategies to reduce the risk of these filarioids in dog and human populations.Graphical

Molecular detection of zoonotic filarioids in Culex spp. from Portugal.

To investigate the role of dipterans in the transmission of Onchocerca lupi and other zoonotic filarioids, samples were collected from different sites in Algarve, southern Portugal, morphologically identified and molecularly tested for filarioids. Culex sp. (72.8%) represented the predominant genus followed by Culicoides sp. (11.8%), Ochlerotatus sp. (9.7%), Culiseta sp. (4.5%), Aedes sp. (0.9%) and Anopheles sp. (0.3%). Nineteen (2.8%) specimens scored positive for filarioids, with Culex pipiens quinquefasciatus (2%) positive for Dirofilaria immitis (1.4%), Dirofilaria repens, Acanthocheilonema reconditum, Onchocerca lupi, unidentified species of Filarioidea (0.2%, each) and Onchocercidae (0.6%). Additionally, Culiseta longiareolata (6.5%), Ochlerotatus caspius (3%) and Culex laticinctus (0.2%) scored positive for unidentified Onchocercidae, A. reconditum and for O. lupi, respectively. This is the first report of the occurrence of DNA of O. lupi, D. repens and A. reconditum in Culex spp. in Portugal. Information regarding the vectors and the pathogens they transmit may help to adopt proper prophylactic and control measures.

Comparison of the temporal efficacy of Aquatain surface films for the control of Anopheles arabiensis and Ochlerotatus caspius larvae from Sudan.

Aquatain mosquito formulation (AMF) is a surfactant that spreads across the surface of water bodies to produce a monomolecular film. This study experimentally evaluates the temporal efficacy of AMF against aquatic stages of Anopheles arabiensis and Ochlerotatus caspius under laboratory conditions. Using the recommended application dose of 1 ml m−2, a large species-specific difference in the median lethal time for L3–L4 larvae was observed. The median lethal time to 50% mortality (LT50) and 90% mortality (LT90) was 1.3 h, 95% CI [1.2, 1.4] and 3.8 h, 95% CI [3.6, 4.0], respectively, for Oc. caspius. The corresponding values for An. arabiensis were 8.1 h, 95% CI [7.3, 9.0] and 59.6 h, 95% CI [48.5, 76.2]. Based on data from published laboratory studies for a total of seven mosquito species, drawn from four genera, results in the following three groups, [LT50 = 1–2 h, Culex quinquefasciatus, Ochlerotatus caspius] [LT50 = 8–24, hours, Anopheles minimus, Anopheles arabiensis, Anopheles gambiae s.s.] and [LT50 = 72–143 h, Anopheles stephensi, Aedes aegypti]. In all experiments, 100% mortality was achieved given sufficient time. The potential relevance of mortality rate estimates, in the context of other studies, on the use of monomolecular films for the control of malaria and arbovirus diseases is discussed.

Comparative Phylogeography and Integrative Taxonomy of Ochlerotatus caspius (Dipera: Culicidae) and Ochlerotatus dorsalis

Given that accurately identifying pathogen vectors is vital for designing efficient mosquito control programs based on the proper surveillance of the epidemiologically important species, it has been suggested the complementary use of independently evolving genes and morphometric traits as a reliable approach for the characterization and delimitation of related species. Hence, we examined the spatial distribution of COI mtDNA and ITS2 rDNA variation from the historical perspective of Ochlerotatus caspius (Pallas, 1771) and O. dorsalis (Meigen, 1830), while simultaneously testing the utility of the two markers in integrative species delimitation when combined with phenotypic character analyses of larvae and adults. Despite the striking difference in haplotype diversity (high in COI mtDNA, low in ITS2 rDNA), no evident phylogeographic structure was apparent in the Palearctic O. caspius. The Holarctic O. dorsalis species was subdivided into two highly distinctive COI mtDNA phylogroups which corresponded to the Nearctic and Palearctic regions. Strong support for the independence of the two allopatric evolutionary lineages suggested that geographical barrier and climatic changes during Pleistocene caused vicariance of the ancestral range. COI mtDNA reliably distinguished O. caspius and O. dorsalis, while ITS2 rDNA yet again lacked the proper resolution for solving this problem. An integrative approach based on the larval and adult morphological traits have varying taxonomic applications due to their differential diagnostic values. Thus, by the implementation of an integrative taxonomic approach, we successfully detected species borders between the two epidemiologically relevant species and uncovered the presence of cryptic diversity within O. dorsalis.

Plasmodium transmission differs between mosquito species and parasite lineages.

Factors such as the particular combination of parasite-mosquito species, their co-evolutionary history and the host's parasite load greatly affect parasite transmission. However, the importance of these factors in the epidemiology of mosquito-borne parasites, such as avian malaria parasites, is largely unknown. Here, we assessed the competence of two mosquito species [Culex pipiens and Aedes (Ochlerotatus) caspius], for the transmission of four avian Plasmodium lineages (Plasmodium relictum SGS1 and GRW11 and Plasmodium cathemerium-related lineages COLL1 and PADOM01) naturally infecting wild house sparrows. We assessed the effects of parasite identity and parasite load on Plasmodium transmission risk through its effects on the transmission rate and mosquito survival. We found that Cx. pipiens was able to transmit the four Plasmodium lineages, while Ae. caspius was unable to transmit any of them. However, Cx. pipiens mosquitoes fed on birds infected by P. relictum showed a lower survival and transmission rate than those fed on birds infected by parasites related to P. cathemerium. Non-significant associations were found with the host-parasite load. Our results confirm the existence of inter- and intra-specific differences in the ability of Plasmodium lineages to develop in mosquito species and their effects on the survival of mosquitoes that result in important differences in the transmission risk of the different avian malaria parasite lineages studied.

Salinity cascading and predator effects on consumer and producer community structure: a mesocosm experiment

1. An observed community structure is often shaped by a combination of bottom‐top and top‐bottom processes, affected by biotic and abiotic factors. These factors affect community structure either directly (each species separately) or indirectly, via other species. Few studies have observed the combined effects of biotic and abiotic factors on primary producers and consumer communities composed of numerous species.2. This study investigated the combined effects of a predatory hemipteran and water salinity on abundance and species richness of the periphyton and arthropod communities in an artificial pool experiment.3. The abundance and species richness of both periphyton and arthropod communities were affected by the combination of salinity and predator.4. It is suggested that the observed consumer community is composed of arthropod species that vary in salinity tolerance and response to the predator. In addition, the abundance of euryhaline species or species that are not consumed by this particular predator increases indirectly in specific treatment combinations that eventually result in reduced interspecific competition. Periphyton variables were strongly correlated to densities of larval Ochlerotatus caspius (Diptera: Culicidae), suggesting that this species may be largely responsible for structuring the producer community.5. It is suggested that O. caspius distribution is the result of female oviposition habitat selection that is manipulated by chemical signals. Therefore, chemical signals that inform about habitat suitability also play an important role in shaping both consumer and primary producer communities.

House sparrow uropygial gland secretions do not attract ornithophilic nor mammophilic mosquitoes.

Mosquito feeding preferences determine host-vector contact rates and represent a key factor in the transmission of vector-borne pathogens. The semiochemical compounds of which vertebrate odours are composed probably play a role in mosquito host choice. Birds spread secretions from uropygial gland over their feathers to protect their plumage, comprising behaviour that may in turn affect odour profiles. Although uropygial secretions are expected to modify the attractiveness of birds to mosquitoes, contradictory findings have been reported. Mosquito species differ in their feeding preferences, with some species feeding mainly on birds (ornithophilic species) and others on mammals (mammophilic species). Consequently, it is possible that ornithophilic and mammophilic species differ in their response to uropygial gland secretions. Using a dual-choice olfactometer, the present study tests this hypothesis by comparing the behavioural response to uropygial gland secretions from juvenile male and female house sparrows (Passer domesticus) in the ornithophilic Culex pipiens and the mammophilic Aedes (Ochlerotatus) caspius mosquitoes. No differences were found in the response of either mosquito species to the uropygial gland secretions. Therefore, the preference of ornithophilic mosquitoes for avian hosts is apparently not explained by a greater attraction of mosquitoes to the uropygial gland secretion odour when presented in combination with a CO2 -enriched airflow.

Molecular Identification of Mammalian Blood Meals in Mosquito Vectors in Nile Delta, Egypt

The degree of contact of the vector and the vertebrate host is an important variable in determining the vectorial capacity of mosquito species for the arthropod-borne disease. This study conducted in Monufia Governorate, Egypt, to describe the mosquito community composition and species-specific host-feeding patterns. Mosquitoes were surveyed over a 2-years period and their host-feeding patterns were determined in relation to species relative abundance by polymerase chain reaction (PCR).This diagnostic technique was used to identify mammalian blood meals from female mosquitoes by sized DNA fragments following agarose gel electrophoresis. One universal reverse primer and five animal-specific forward primers included Human, Pig, Cow, Dog and Goat were used. Multiple blood meals from distinctive mammalian hosts were identified from single mosquito abdomens. Ninety-nine mosquito blood meals from four mosquito species were identified, 67.7% (67) were mixed blood. Both Cx. pipiens and Cx. antennatus fed on human and animals but feeding strategies differed from outdoors to indoors. Inside houses engorged female Cx. pipiens accounted for (94) 74% of collections and out of this, 53.8% fed on humans as single blood and 40% as mixed blood. However, outdoor, collected Ochlerotatus caspius constituted 7.1% of the collected females. Results suggested that, Cx. pipiens an important bridge of disease vector to humans in Egypt.

A Survey of Aedes (Diptera: Culicidae) Mosquitoes in Tunisia and the Potential Role of Aedes detritus and Aedes caspius in the Transmission of Zika Virus.

The present study aimed to update the list of Aedes mosquito species occurring in Tunisia and to test the vector competence of Aedes (Ochlerotatus) caspius (Pallas) and Ae. (Ochlerotatus) detritus (Haliday), the locally most abundant and widespread species, to transmit Zika virus (ZIKV). In 2017-2018, mosquito larvae were collected from 39 different larval habitats in seven bioclimatic zones of Tunisia. The salinity and pH of each breeding site were measured. The survey revealed the presence of 10 Aedes species in Tunisia: Ae. (Stegomyia) albopictus (Skuse), Ae. (Ochlerotatus) berlandi (Séguy), Ae. caspius, Ae. detritus, Ae. (Finlaya) echinus (Edwards), Ae. (Finlaya) geniculatus (Olivier), Ae. (Acartomyia) mariae (Sergent and Sergent), Ae. (Ochlerotatus) pulcritarsis (Rondani), Ae. (Aedimorphus) vexans (Meigen), and Ae. (Fredwardsius) vittatus (Bigot). Of these 10 species, Ae. caspius and Ae. detritus were the most abundant in Tunisia. Aedes detritus and Ae. caspius larvae were reared until the imago stage under insectary conditions to test autogeny. The study showed that Ae. detritus is autogenous and stenogamous and Ae. caspius, anautogenous and eurygamous. Finally, the collected strains of these two species were experimentally infected with the Asian genotype of ZIKV, originally isolated from a patient in April 2014 in New Caledonia, to test their vector competence. Neither of these species was able to transmit ZIKV at 7 and 14 d postexposure. Further investigations are needed to test the competence of other Tunisian mosquito species that may be associated with ZIKV transmission.

Effects of host sex, body mass and infection by avian Plasmodium on the biting rate of two mosquito species with different feeding preferences

BackgroundThe transmission of mosquito-borne pathogens is strongly influenced by the contact rates between mosquitoes and susceptible hosts. The biting rates of mosquitoes depend on different factors including the mosquito species and host-related traits (i.e. odour, heat and behaviour). However, host characteristics potentially affecting intraspecific differences in the biting rate of mosquitoes are poorly known. Here, we assessed the impact of three host-related traits on the biting rate of two mosquito species with different feeding preferences: the ornithophilic Culex pipiens and the mammophilic Ochlerotatus (Aedes) caspius. Seventy-two jackdaws Corvus monedula and 101 house sparrows Passer domesticus were individually exposed to mosquito bites to test the effect of host sex, body mass and infection status by the avian malaria parasite Plasmodium on biting rates.ResultsOchlerotatus caspius showed significantly higher biting rates than Cx. pipiens on jackdaws, but non-significant differences were found on house sparrows. In addition, more Oc. caspius fed on female than on male jackdaws, while no differences were found for Cx. pipiens. The biting rate of mosquitoes on house sparrows increased through the year. The bird infection status and body mass of both avian hosts were not related to the biting rate of both mosquito species.ConclusionsHost sex was the only host-related trait potentially affecting the biting rate of mosquitoes, although its effect may differ between mosquito and host species.

Ecological and Behavioral Studies of Mosquito Vectors in Monufia, Nile Delta, Egypt.

Continuous monitoring of vector species composition, abundance, dynamics, biting and resting habits is the base to determine the local vector species that affect disease transmission patterns and consequently the choice of cost-effective vector control options. For targeting that, adult mosquito surveys were conducted in Monufia as a representative of the Egyptian governorates in Nile-Delta (Spring 2016– Winter 2018). Totally, 4 species were reported in the selected villages: Culex (Culex) pipiens Linnaeus, Cx. (Cx.) perexiguus Theobald, Cx. (Cx.) antennatus Becker and Ochlerotatus (Ochlerotatus) caspius Pallas. Culex pipiens was the predominant species in all study regions. For each species, the following were examined: the relation of adult indoor and outdoor density with temperature and relative humidity as well as its indoor and outdoor resting density and its relation with temperature and relative humidity, determination of the endophagic and exophagic indices for mosquito biting reference and the seasonal changes in parity status.

Mosquito community influences West Nile virus seroprevalence in wild birds: implications for the risk of spillover into human populations

Mosquito community composition plays a central role in the transmission of zoonotic vector-borne pathogens. We evaluated how the mosquito community affects the seroprevalence of West Nile virus (WNV) in house sparrows along an urbanisation gradient in an area with the endemic circulation of this virus. We sampled 2544 birds and 340829 mosquitoes in 45 localities, analysed in 15 groups, each containing one urban, one rural and one natural area. WNV seroprevalence was evaluated using an epitope-blocking ELISA kit and a micro virus-neutralization test (VNT). The presence of WNV antibodies was confirmed in 1.96% and 0.67% of birds by ELISA and VNT, respectively. The VNT-seropositive birds were captured in rural and natural areas, but not in urban areas. Human population density was zero in all the localities where VNT-positive birds were captured, which potentially explains the low incidence of human WNV cases in the area. The prevalence of neutralizing antibodies against WNV was positively correlated with the abundance of the ornithophilic Culex perexiguus but negatively associated with the abundance of the mammophilic Ochlerotatus caspius and Anopheles atroparvus. These results suggest that the enzootic circulation of WNV in Spain occurs in areas with larger populations of Cx. perexiguus and low human population densities.

Field application of MALDI-TOF MS on mosquito larvae identification.

In recent years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as an efficient tool for arthropod identification. Its application for field monitoring of adult mosquitoes was demonstrated, but identification of larvae has been limited to laboratory-reared specimens. Study aim was to test the success of MALDI-TOF MS in correctly identifying mosquito larvae collected in the field. Collections were performed at 13 breeding sites in urban areas of Marseille, a city in the South of France. A total of 559 larvae were collected. Of these, 73 were accurately morphologically identified, with confirmation either by molecular identification (n = 31) or analysis with MALDI-TOF MS (n = 31) and 11 were tested using both methods. The larvae identified belonged to six species including Culiseta longiareolata, Culex pipiens pipiens, Culex hortensis, Aedes albopictus, Ochlerotatus caspius and Anopheles maculipennis. A high intra-species reproducibility and inter-species specificity of whole larva MS spectra was obtained and was independent of breeding site. More than 92% of the remaining 486 larvae were identified in blind tests against the MS spectra database. Identification rates were lower for early and pupal stages, which is attributed to lower protein abundance and metamorphosis, respectively. The suitability of MALDI-TOF MS for mosquito larvae identification from the field has been confirmed.

Mosquito species involved in the circulation of West Nile and Usutu viruses in Italy.

Usutu (USUV) and West Nile (WNV) are mosquito-borne Flavivirus emerged in Italy in 1996 and 1998, respectively, and reappeared 10 years later. The aim of this work is to review the Italian mosquito species found positive for WNV and USUV between 2008 and 2014. Moreover, the role of mosquitoes in promoting the overwintering of these viruses is discussed, as a result of the mosquito collections performed in Molise region between September 2010 and April 2011. Overall 99,000 mosquitoes were collected: 337 and 457 mosquito pools tested positive by real time reverse transcriptase polymerase chain reaction (real time RT-PCR) for WNV and USUV, respectively. West Nile virus was detected in pools of Culex pipiens s.l. (329), Ochlerotatus caspius (4), Culex modestus (2), and Culex spp. (2). Positive USUV pools were from Cx. pipiens s.l. (435), Aedes albopictus (12), Oc. caspius (5), Culex spp. (2), Anopheles maculipennis s.l. (1), Culiseta annulata (1), and Ochlerotatus detritus (1). In Molise region, 1,694 mosquitoes were collected, and USUV was identi ed in Cx. pipiens s.l., Cs. annulata, and Oc. detritus pools. This paper shows that Cx. pipiens s.l. is the mosquito species most involved in the WNV and USUV circulation in Italy, although other species would also support the spread of both the viruses during Winter.