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At least 19 recordsLinked to original sources
PubMed1988

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 2. Damage to ingested microfilariae by mosquito foregut armatures and development of filarial larvae in mosquitoes.

Microfilariae (mf) of Wuchereria bancrofti from the midgut of 639 Anopheles gambiae, 557 An. arabiensis, 117 An. melas and 9 An. funestus were examined immediately after the mosquitoes had fed on carriers with different densities of mf. The percentages of mf damaged during ingestion were 57.1-60.0 in An. gambiae, 33.3-50.6 in An. arabiensis and 38.7-55.7 in An. melas. In each species the percentage of mf damaged was independent of mf density in the human host. A further 3657 An. gambiae, 2875 An. arabiensis, 347 An. melas and 32 An. funestus were examined 7 d or more after feeding on mf carriers. In An. gambiae and An. arabiensis, mean numbers of larvae per mosquito were strongly correlated to mf blood density, with similar regression slopes to those obtained from the regression of mf blood density on mean uptake of mf/mosquito. The ratio of mean numbers of larvae per mosquito to mean numbers of intact mf ingested per mosquito increased as the density of mf in the human host increased in An. gambiae and An. arabiensis, but decreased in An. melas as host mf density increased.

Animals↗
PubMed1987

Toxic effects of mosquito coil (a mosquito repellent) smoke on rats. I. Properties of the mosquito coil and its smoke.

The physical and chemical properties of the mosquito coil, a commonly used mosquito repellent in Asia and South America, were analysed. The smoke emitted from the burning mosquito coil consists of submicron particles (diameter less than 1 micron) coated with a considerable amount of heavy metals, allethrin and a wide range of organic vapors, such as phenol and o-cresol. Therefore, a lengthy exposure to this smoke will cause adverse effects on the consumers.

Allethrins↗
PubMed2025

A new potential mosquito-borne virus: detection of Human-derived Jingmenvirus in several-species of mosquitoes from Yaoundé, Cameroon.

BACKGROUND: Tick-borne Jingmenviruses are becoming an increasing arbovirus concern due to the rising number of reported infections in humans and animals, as well as their wide geographic distribution. The involvement of other hematophagous arthropods as vectors of Jingmenviruses is still unknown. METHODS: Mosquitoes were sampled in two different biotopes in Cameroon (Yaoundé and Garoua) during the rainy and the dry seasons in 2022 and 2023. Metatranscriptomics Next Generation Sequencing was conducted using Illumina technology. Viral sequences detection revealed the presence of several contigs with high sequence identity to a human-derived Jingmenvirus (HdJV) previously discovered in plasma from an individual from Yaoundé, Cameroon. A draft viral genome was constituted for each Jingmenvirus-positive samples. Maximum likelihood phylogenetic reconstructions were used to position mosquito-associated viruses within the diversity of Jingmenviruses. Statistical analyses were conducted to estimate the prevalence of infected mosquitoes and the effect of different variables (region, season, year, mosquito species) on Jingmenvirus detection. RESULTS: HdJV was identified during the dry and the rainy seasons in 4 species of mosquitoes: Aedes albopictus, Culex quinquefasciatus and Culex wansoni from Yaoundé, and Anopheles gambiae s.l. from Garoua. The overall prevalence of HdJV-infected mosquitoes was estimated to 0.90% [0.41-1.69]; and the unique variable significantly associated with HdJV detection was the sampling area: Yaoundé showed the highest prevalence (2.29% [0.95-4.68]) compared to Garoua (0.18% [0.01-0.79]). Mosquito-associated Jingmenviruses shared a high nucleotide identity (between 98.64-100% according to the segment) and clustered in the same clade in the phylogenetic analysis, that they belong to the same viral species circulating in different mosquito species. The viral genome shared between 96.4% and 98.9% nucleotide identity with a HdJV detected in the plasma of a patient suffering from febrile illness originating from the same area, suggesting the possible involvement of mosquitoes as vectors of arboviral Jingmenviruses in human infections. CONCLUSIONS: This finding provides new insights into the ecology and transmission dynamics of Jingmenviruses, highlighting mosquitoes as potential vectors, alongside ticks, in the zoonotic transmission of this virus group.

Jingmenvirus↗
PubMed1996

Immunologic mechanisms in mosquito allergy: correlation of skin reactions with specific IgE and IgG antibodies and lymphocyte proliferation response to mosquito antigens.

BACKGROUND: Allergic reactions to mosquito bites are a common problem. Although IgE-mediated hypersensitivity has been reported, other immunologic mechanisms may be involved. OBJECTIVES: To study the relationship between skin bite reactions and immunologic parameters. METHODS: Forty-one subjects were experimentally exposed to mosquito (Aedes vexans) bites. Immediate and delayed skin reactions were traced at 20 minutes and 24 hours, respectively, after the bites. Sera were analyzed for mosquito salivary gland-specific IgE (mosquito-IgE) and IgG (mosquito-IgG) by ELISA. Lymphocyte proliferation assays with mosquito extract were also performed. RESULTS: One of 41 subjects had only a delayed skin reaction to the bite, 23 had both immediate and delayed reactions, 6 had only immediate reactions, and 11 had no reaction. The mean mosquito-IgE and -IgG concentrations were higher in the subjects with immediate reactions than in those without immediate reactions (P < .007). The mean lymphocyte proliferation stimulation index was higher in the subjects with delayed reactions than in those without delayed reactions (P < .015). Further, both mosquito-IgE and -IgG levels correlated with skin immediate and delayed reactions (P < .04), while lymphocyte proliferation indices only correlated with skin delayed reactions (P < .006). Inverse correlations were found between the size of skin reactions and the number of years lived in Canada (P < .04), but not with age. CONCLUSION: These results indicate that IgE-, lymphocyte- and, probably, local IgG immune-complex-mediated hypersensitivities are involved in mosquito allergy. Naturally acquired desensitization to mosquito bites occurs during long-term exposure.

Adult↗
PubMed2001

Both mosquito-derived xanthurenic acid and a host blood-derived factor regulate gametogenesis of Plasmodium in the midgut of the mosquito.

Gametogenesis of Plasmodium in vitro can be induced by the combined stimulus of a 5 degrees C fall in temperature and the presence of xanthurenic acid (XA). In-vitro experiments showed that P. gallinaceum (EC(50)=80 nM) is much more sensitive to XA than P. berghei (9 microM), P. yoelii (8 microM), and P. falciparum (2 microM). However, in the mosquito vector, we do not know whether the temperature shift and XA are the only gametocyte-activating factors (GAF), nor do we know with certainty the true source(s) of XA in the mosquito blood meal. Previous studies indicate that XA is the only source of GAF in the mosquito. By defining, and then contrasting, the ability of an XA-deficient mutant of Aedes aegypti, with the wild-type mosquito to support exflagellation and ookinete formation in vivo, we determined the roles of parasite-, mosquito- and host blood-derived GAF in the regulation of gametogenesis of P. gallinaceum. Removal of both host and vector sources of GAF totally inhibited both exflagellation and ookinete production, whilst the lack of either single source resulted in only a partial reduction of exflagellation and ookinete formation in the mosquito gut. Both sources can be effectively replaced/substituted by synthetic XA. This suggests (1) both mosquito- and vertebrate-derived factors act as GAF in the mosquito gut in vivo; (2) the parasite itself is unable to produce any significant GAF activity. Studies are underway to determine whether vertebrate-derived GAF is XA. These data may form the basis of further studies of the development of new methods of interrupting malarial transmission.

Aedes↗
PubMed2001

Anti-mosquito midgut antibodies block development of Plasmodium falciparum and Plasmodium vivax in multiple species of Anopheles mosquitoes and reduce vector fecundity and survivorship.

The mosquito midgut plays a central role in the sporogonic development of malaria parasites. We have found that polyclonal sera, produced against mosquito midguts, blocked the passage of Plasmodium falciparum ookinetes across the midgut, leading to a significant reduction of infections in mosquitoes. Anti-midgut mAbs were produced that display broad-spectrum activity, blocking parasite development of both P. falciparum and Plasmodium vivax parasites in five different species of mosquitoes. In addition to their parasite transmission-blocking activity, these mAbs also reduced mosquito survivorship and fecundity. These results reveal that mosquito midgut-based antibodies have the potential to reduce malaria transmission in a synergistic manner by lowering both vector competence, through transmission-blocking effects on parasite development, and vector abundance, by decreasing mosquito survivorship and egg laying capacity. Because the intervention can block transmission of different malaria parasite species in various species of mosquitoes, vaccines against such midgut receptors may block malaria transmission worldwide.

Animals↗
PubMed1991

Cutaneous reactivity to mosquito bites: effect of cetirizine and development of anti-mosquito antibodies.

Cutaneous reactivity to mosquito bites was examined in 27 adult volunteers exposed to Aedes communis mosquitoes. Twenty-three subjects showed a combination of immediate wealing and delayed bite-papules, two subjects each experienced only immediate or delayed cutaneous reactions and two were non-responsive to the bites. The mean size of wealing and the mean score of pruritus was similar in 19 non-atopic and in eight atopic volunteers. These results confirm that normal subjects exhibit different stages of sensitization to mosquito bites. At the onset of the mosquito season, immunoblotting showed that four of 21 subjects (19%) had IgG-class antibodies to a recently described 21.5 kD Aedes communis mosquito antigen. After a 10-day exposure to a mean of 47 mosquito bites, these antibodies were found in 10 subjects (48%) who exhibited both strong and weak cutaneous bite-lesions. A placebo-controlled, double-blind study with cetirizine 10 mg was performed to examine the effect of this non-sedating antihistamine on mosquito bites. The bite lesions were measured and pruritus scored at 15 min, 60 min, 12 hr, and 24 hr. Cetirizine decreased significantly immediate wealing and pruritus (P less than 0.01), but had no effect on the delayed symptoms. This result supports the view that immediate mosquito-bite reactions are histamine-mediated.

Adolescent↗
PubMed1998

Induced immunity against the mosquito Anopheles stephensi Liston (Diptera: Culicidae): effects on mosquito survival and fecundity.

Mice were immunised three to five times with extracts of Anopheles stephensi heads, midguts, ovaries or fat bodies. At each immunisation the effects of feeding An. stephensi on the mice was determined, and changes in mosquito longevity and fecundity examined as the immune response developed. Although variability was common between control cages, significant and consistent reductions in mosquito longevity were observed when midguts were used as immunogens. Other extracts caused transient reductions in mortality. Fecundity was reduced significantly in mosquitoes fed upon mice immunised with each extract in at least one experiment. Mosquitoes fed upon fat-body-immunised mice showed delayed egg-laying as well as overall reduction in fecundity. The results confirm the feasibility of targeting mosquito antigens for novel vaccine development, but the "shotgun" approach used probably fails to successfully hit a suitable target antigen with any consistency. The natural variation in mosquito mortality can be countered by rigorous statistical analysis which can identify subtle effects in a very "noisy" experimental system. The midgut is the obvious target organ for anti-mosquito vaccine development and future work will focus on targeting components of this tissue for further immunisations.

Adipose Tissue↗
PubMed1996

Inhibition of mosquito salivary gland apyrase activity by antibodies produced in mice immunized by bites of Anopheles stephensi mosquitoes.

Mice (BALB/c) were immunized to mosquito saliva by repeated bites of Anopheles stephensi mosquitoes. Studies were conducted on the ability of these mice to develop antibodies against the apyrase component of the saliva. By means of immunoprecipitation procedures and Western blot analysis, we demonstrated the presence of antiapyrase antibodies to the mosquito saliva. Furthermore, these antibodies were able to inhibit apyrase activity. Serum titers of 1:20 were able to inhibit approximately 90% of salivary gland apyrase activity, while titers of 1:160 retained the ability to inhibit more than 50% of apyrase activity. Parallel inhibition assays with immunoglobulin G (IgG) from immunized versus nonimmunized mice showed that the inhibitory activity of serum from immunized mice could be accounted for by its IgG component. Mosquito salivary gland apyrase has previously been shown to facilitate mosquito feeding by inhibiting aggregation of platelets at the mosquito bite site. However, our studies have shown that mosquitoes feeding on immunized mice had no deficiency in probing these mice for a blood meal, even in the face of high titers of anti-apyrase antibodies.

Animals↗
PubMed2017

Infection rate of Aedes aegypti mosquitoes with dengue virus depends on the interaction between temperature and mosquito genotype.

Dengue fever is the most prevalent arthropod-transmitted viral disease worldwide, with endemic transmission restricted to tropical and subtropical regions of different temperature profiles. Temperature is epidemiologically relevant because it affects dengue infection rates in Aedes aegypti mosquitoes, the major vector of the dengue virus (DENV). Aedes aegypti populations are also known to vary in competence for different DENV genotypes. We assessed the effects of mosquito and virus genotype on DENV infection in the context of temperature by challenging Ae. aegypti from two locations in Vietnam, which differ in temperature regimes, with two isolates of DENV-2 collected from the same two localities, followed by incubation at 25, 27 or 32&#xb0;C for 10 days. Genotyping of the mosquito populations and virus isolates confirmed that each group was genetically distinct. Extrinsic incubation temperature (EIT) and DENV-2 genotype had a direct effect on the infection rate, consistent with previous studies. However, our results show that the EIT impacts the infection rate differently in each mosquito population, indicating a genotype by environment interaction. These results suggest that the magnitude of DENV epidemics may not only depend on the virus and mosquito genotypes present, but also on how they interact with local temperature. This information should be considered when estimating vector competence of local and introduced mosquito populations during disease risk evaluation.

Aedes↗
PubMed1991

Selection of cyanobacteria isolated from mosquito breeding sites as a potential food source for mosquito larvae.

One way to increase the persistence of larvicidal toxins in mosquito breeding sites is to clone the corresponding genes in microorganisms, such as cyanobacteria, which could serve as a source of food for the larvae. We isolated and cultured 10 strains of cyanobacteria from three mosquito breeding sites along the French Mediterranean coast. Most of the strains were tolerant to a relatively wide range of salt concentrations, and all of them were totally or partially resistant to at least four of the five biological or chemical larvicides used in the local mosquito control program. Six unicellular strains from these habitats and Synechococcus strain PCC 7942, a strain maintained for more than 10 years under laboratory conditions, were assessed for ingestion and digestion by larvae Culex pipiens and Anopheles gambiae mosquitoes. The numbers of cells ingested and digested were dependent on the cyanobacterial strain and varied with the mosquito species. Three of the new isolates, Synechococcus strain PCC 8905 and Synechocystis strains PCC 8906 and PCC 8912, were ingested and digested rapidly by larvae of both mosquito species. Since these strains are also tolerant to larvicides and relatively resistant to elevated salt concentrations, they meet the basic requirements for potential recipients of bacterial genes that encode endotoxins.

Animals↗
PubMed1989

Significant associations between mosquito control service requests and mosquito populations.

Correlation and multiple regression analyses were used to examine the relationships between mosquito population densities and the numbers of telephone requests for mosquito control services made by people in Polk County, Florida. In 32 of 42 census tracts, there were significant (P less than 0.05) correlations between mosquitoes and requests and that, for 16 tracts, a significant linear relationship could be demonstrated between service requests and only one mosquito taxon. The significant associations were dependent on the types of mosquitoes rather than the relative abundance among mosquito groups. Service requests were most often related to Aedes, followed in importance by Culex salinarius and Anopheles; least often to Cx. nigripalpus. Evidence to support a cause and effect relationship is also presented.

Aedes↗
PubMed2002

Plasmodium-mosquito interactions, phage display libraries and transgenic mosquitoes impaired for malaria transmission.

Malaria continues to kill millions of people every year and new strategies to combat this disease are urgently needed. Recent advances in the study of the mosquito vector and its interactions with the malaria parasite suggest that it may be possible to genetically manipulate the mosquito in order to reduce its vectorial capacity. Here we review the advances made to date in four areas: (1) the introduction of foreign genes into the mosquito germ line; (2) the characterization of tissue-specific promoters; (3) the identification of gene products that block development of the parasite in the mosquito; and (4) the generation of transgenic mosquitoes impaired for malaria transmission. While initial results show great promise, the problem of how to spread the blocking genes through wild mosquito populations remains to be solved.

Animals↗
PubMed1994

Inhibition of malaria parasite development in mosquitoes by anti-mosquito-midgut antibodies.

The mosquito midgut plays a central role in the development and subsequent transmission of malaria parasites. Using a rodent malaria parasite, Plasmodium berghei, and the mosquito vector Anopheles stephensi, we investigated the effect of anti-mosquito-midgut antibodies on the development of malaria parasites in the mosquito. In agreement with previous studies, we found that mosquitoes that ingested antimidgut antibodies along with infectious parasites had significantly fewer oocysts than mosquitoes in the control group. We also found that the antimidgut antibodies inhibit the development and/or translocation of the sporozoites. Together, these observations open an avenue for research toward the development of a vector-based malaria parasite transmission-blocking vaccine.

Animals↗
PubMedDate not supplied

Mosquito allergy: recombinant mosquito salivary antigens for new diagnostic tests.

In patients with mosquito allergy, lack of a readily available, sensitive, specific, safe test is the major obstacle to accurate diagnosis. Three recombinant mosquito salivary antigens, rAed a 1 (68 kD), rAed a 2 (37 kD) and rAed a 3 (30 kD), from Aedes aegypti have been cloned, expressed, purified and characterized. All three recombinant antigens are shared by Aedes vexans and other mosquito species, and all have been found to have biologic activity in humans. In recent studies, 43% of 28 mosquito bite test-positive subjects had a positive skin test to rAed a 1, 11% to rAed a 2 and 32% to rAed a 3. The sizes of the skin test reactions to the recombinant antigens correlated with the sizes of the A. aegypti bite test reactions. None of 15 A. aegypti bite test-negative subjects had a positive skin test to any of the recombinant antigens. Recombinant mosquito salivary antigens will facilitate the diagnosis of mosquito allergy.

Aedes↗
PubMed2001

A live attenuated recombinant dengue-4 virus vaccine candidate with restricted capacity for dissemination in mosquitoes and lack of transmission from vaccinees to mosquitoes.

2Adelta30 is a live dengue-4 virus vaccine candidate with a 30-nucleotide deletion in its 3'-untranslated region. To assess the transmissibility of 2Adelta30 by mosquitoes, we compared its in vivo replication in mosquitoes with that of its wild type DEN-4 parent. Both the vaccine candidate and wild type virus were equally able to infect the mosquito Toxorhynchites splendens after intrathoracic inoculation. Relative to its wild type parent, 2Adelta30 was slightly restricted in its ability to infect the midgut of Aedes aegypti mosquitoes fed on an artificial blood meal and was even more restricted in its ability to disseminate from the midgut to the salivary glands. Thus, the 30-nucleotide deletion rendered the vaccine candidate more sensitive than its wild type parent to the mosquito midgut escape barrier. Most significantly, 2Adelta30 was not transmitted to 352 Ae. albopictus mosquitoes fed on 10 vaccinees, all of whom were infected with the vaccine candidate.

Adult↗
PubMed2002

Late season commercial mosquito trap and host seeking activity evaluation against mosquitoes in a malarious area of the Republic of Korea.

Field trials evaluating selected commercially available mosquito traps variously baited with light, carbon dioxide, and/or octenol were conducted from 18-27 September 2000 in a malarious area near Paekyeon-ri (Tongil-Chon) and Camp Greaves in Paju County, Kyonggi Province, Republic of Korea. The host-seeking activity for common mosquito species, including the primary vector of Japanese encephalitis, Culex tritaeniorhynchus Giles, was determined using hourly aspirator collections from a human and propane lantern-baited Shannon trap during hours when temperatures exceeded 15 degrees C. The total number of mosquitoes and number of each species captured during the test was compared using a block design. Significant differences were observed for the total number of mosquitoes collected, such that, the Mosquito MagnetTM with octenol > Shannon trap > ABC light trap with light and dry ice > Miniature Black Light trap (manufactured by John W. Hock) > or = New Jersey Trap > ABC light trap with light only. Significant differences in numbers collected among traps were noted for several species including: Aedes vexans (Meigen), Anopheles lesteri Baisas and Hu. An. sinensis Weidemann. An. sineroides Yamada, An. yatsushiroensis Miyazaki, Culex pipiens pallens Coquillett L., Cx. orientalis Edwards and Cx. tritaeniorhynchus. Host-seeking activity for most common species showed a similar bimodal pattern. Results from these field trap evaluations can significantly enhance current vector and disease surveillance efforts especially for the primary vector of Japanese encephalitis, Cx. tritaeniorhynchus.

Animals↗
PubMed1994

Public perception of mosquito annoyance measured by a survey and simultaneous mosquito sampling.

For randomly chosen residents of the Minneapolis-St. Paul, Minnesota, metropolitan area, survey responses, reported bites, and observed defensive behaviors (e.g., brushing, swatting) for a 5-min period in their yard were compared with simultaneous mosquito counts from a human-baited drop-net trap 6 m from the resident. When mosquitoes trapped, reported bites, or observed behaviors per 5 min were 3 or more, the majority of respondents described the mosquito levels as greater than "moderate" and anticipated reduced outdoor time and/or possible repellent use. At 25 or more mosquitoes trapped, 11 or more reported bites, or 16 or more observed behaviors per 5 min, response was "bad", with most people anticipating a major reduction in outdoor time (without repellent), "probably" or "definitely" planning to use repellent, and anticipating some outdoor time loss even if using repellent. Levels of less than 3 mosquitoes trapped per 5 min were related to moderate annoyance in 20-45% of the population. Individual response was highly variable, and the personal and environmental covariates measured did not account for more than half the variability.

Adult↗