Detection and genetic characterization of arboviruses and other viruses from mosquitoes collected in southeastern and central Senegal, October 2022.

The composition, density, diversity, and temporal distribution of mosquito species and the influence of temperature, relative humidity, and rainfall on these data were investigated in 50 sites across five land cover classes (forest, savannah, barren, village, and agriculture) in southeastern Senegal. Mosquitoes were collected monthly in each site between June 2009 and March 2011, with three people collecting mosquitoes landing on their legs for one to four consecutive days. In total, 81,219 specimens, belonging to 60 species and 7 genera, were collected. The most abundant species were Aedes furcifer (Edwards) (Diptera: Culicidae) (20.7%), Ae. vittatus (Bigot) (19.5%), Ae. dalzieli (Theobald) (14.7%), and Ae. luteocephalus (Newstead) (13.7%). Ae. dalzieli, Ae. furcifer, Ae. vittatus, Ae. luteocephalus, Ae. taylori Edwards, Ae. africanus (Theobald), Ae. minutus (Theobald), Anopheles coustani Laveran, Culex quinquefasciatus Say, and Mansonia uniformis (Theobald) comprised ≥10% of the total collection, in at least one land cover. The lowest species richness and Brillouin diversity index (HB = 1.55) were observed in the forest-canopy. The urban-indoor fauna showed the highest dissimilarity with other land covers and was most similar to the urban-outdoor fauna following Jaccard and Morisita index. Mosquito abundance peaked in June and October 2009 and July and October 2010. The highest species density was recorded in October. The maximum temperature was correlated positively with mean temperature and negatively with rainfall and relative humidity. Rainfall showed a positive correlation with mosquito abundance and species density. These data will be useful for understanding the transmission of arboviruses and human malaria in the region.

Mosquito species previously reported to be susceptible to Plasmodium gallinaceum include 13 species of Aedes, 5 species of Armigeres and 2 species of Culex (Brumpt 1936, Roubaud, Colas-Belcour and Mathis 1939, Vargas and Beltran 1941, Russell and Mohan 1942, Russell and Menon 1942). These records include only 3 species indigenous to North America, i.e., Aedes vexans Meigen, Aedes aegypti Linnaeus and Culex quinquefasciatus Say. This report includes the results of observations on 2 American species that have and 7 that have not been previously studied. The mosquitoes were either reared from larvae or captured in the field as adults. They were allowed to feed on an infected chicken and were kept at 28? C. From 3 to 9 days later most of them were dissected and examined for o6cysts. A few were examined for sporozoites and oocysts after 9 to 21 days. As may be seen in Table 1, oocysts were observed in Aedes camnpestris Dyar and

West Nile virus (WNV) is currently active in Kenya as evidenced by the detection of antibodies in birds bled as part of an avian influenza surveillance program in 2009. Although WNV has been isolated from several mosquito species in Kenya, no studies have ever been conducted to determine which of these species are competent vectors of this virus. Therefore, we allowed Kenyan mosquitoes to feed on 2- or 3-d-old chickens that had been infected with a Lineage one strain of WNV 24-48 h earlier. These mosquitoes were tested approximately 2 wk later to determine infection, dissemination, and transmission rates. All five species [Culex quinquefasciatus Say, Culex univittatus Theobald, Culex vansomereni Edwards, Mansonia africana (Theobald), and Mansonia uniformis (Theobald)] were susceptible to infection, but disseminated infections were detected only in the three Culex, and not the two Mansonia species. Culex mosquitoes with a disseminated infection readily transmitted virus by bite, but even when inoculated with WNV, the two Mansonia failed to transmit virus, indicating a salivary gland barrier. These studies indicate that the three Culex species may play a role in the transmission of WNV in Kenya.

Abstract. Chaiphongpachara T. 2019. Short Communication: A checklist of the mosquito species (Diptera: Culicidae) in the Suan Phueng District, Ratchaburi Province, Thailand. Biodiversitas 20: 468-473. Mosquito is a medically important insect, which is a vector to transmit pathogens to humans. There are several methods to reduce the numbers mosquitoes, which requires entomological knowledge. It is critical to know the species of mosquitoes in the area to choose the most suitable method to provide vector control, specifically, to target mosquito species. In this study, we investigated the species of mosquito vectors in the Huay Nam Nak Village in the Suan Phueng District, Ratchaburi Province, Thailand, which is an endemic area of mosquito-borne diseases, especially malaria and dengue fever. Mosquito species were collected by the Mosquito Magnet® Independence trap from the Huay Nam Nak Village. A total of 1,002 mosquitoes, divided into eight species in four genera, including Anopheles barbirostris s.l. van der Wulp (118 individuals), An. subpictus s.l. Grassi (127 individuals), Culex quinquefasciatus Say (186 individuals), Cx. vishnui Theobald (204 individuals), Cx. whitmorei Giles (198 individuals), Aedes aegypti Linnaeus (45 individuals), Ae. albopictus Skuse (78 individuals), and Armigeres subalbatus Coquillett (46 individuals). This checklist of the mosquito species is very important information to set mosquito control measures that suit each area.

Information on the mosquito species that transmit canine filariosis is scanty. Hence, an experimental study was conducted to identify the potential vectors responsible for the transmission of D. immitis Leidy and B. pahangi Buckley & Edeson. A total of 367 mosquitoes belonging to six species containing both laboratory and field strains (i.e. Aedes togoi Theobald, Aedes aegypti Linnaeus, Aedes albopictus Skuse, Culex quinquefasciatus Say, Culex vishnui Theobald and Anopheles dirus Peyton & Harrison) were used in this study. All mosquitoes were artificially fed on either D. immitis or B. pahangi microfilariae (mfs) infected blood by using the Hemotek™ membrane feeding system. Out of 367 mosquitoes, 228 (64.9%) were fully engorged. After feeding on D. immitis (20%) and B. pahangi (33%) mfs positive blood, the mortality rates for Cx. quinquefasciatus were found to be slightly lower than that of other species of mosquitoes. On the other hand, majority of An. dirus were found to be incapable to withstand the infection of mfs as the mortality rates were relatively high (D. immitis = 71.4%; B. pahangi = 100.0%). Brugia pahangi was detected in Ae. togoi and Cx. quinquefasciatus with infection rates of 50% and 25%, respectively. Aedes togoi was the only species infected with D. immitis with an infection rate of 69%. Our results showed that Ae. togoi was an excellent experimental vector for both D. immitis and B. pahangi. This study also documented the observation of B. pahangi, for the first time in the head region of Cx. quinquefasciatus under a laboratory setting.

Cell hypertrophy was the first reaction of the gut epithelial cells of Aedes aegypti (L.), Anopheles albitarsis (Lynch-Arribálzaga) and Culex quinquefasciatus (Say) to the toxins of strains 2362 and S1116 of Bacillus sphaericus, as cells had an increase of intracellular secretory activity. Soon after the cell hypertrophy developed, vesicles were formed at the cell apical portion, which detached with the plasma membrane, characterizing a type of apocrine secretion like. The first pathway of contamination of the mosquito larvae by these bacteria is through the gut, by feeding. Depending on the species of Culicidae and on the bacterial strain used, the hypertrophy of the gut epithelium occurred between 5 and 15 min after exposure to the contaminated environment. The second aspect observed after hypertrophy was the increase in apocrine secretion. The basophilic vesicles that detached from the cells remained between the peritrophic membrane and the gut lumen, such vesicles were filled with material of unknown nature. The gut posterior region showed secretory activity in both control and treated larvae, being much more intense in bacteria-exposed larvae. There were remarkable differences in the epithelial cell reaction according to the toxins of the two bacterial strains, but C.quinquefasciatus was the most susceptible. Differences in the gut cell reactions to the toxins produced by the two bacterial strains are discussed.

Larvicidal and ovicidal activities of phenyl acetic acid isolated from Streptomyces collinus against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

Effect of compound Musizin isolated from Rhamnus wightii Wight and Arn on the immature stages of filarial vector mosquito Culex quinquefasciatus Say (Diptera: Culicidae) and its non-target studies

Mosquito-borne diseases pose significant public health challenges, necessitating the development of effective and sustainable vector control strategies. This study investigated the feeding preferences of 4 mosquito species (Aedes aegypti Linnaeus, Aedes albopictus Skuse, Culex quinquefasciatus Say, and Anopheles quadrimaculatus Say) for various fruit juices using a home-made choice chamber. We also assessed the impact of combining biogents lure and boric acid into attractive toxic sugar baits to enhance mosquito attraction and mortality. Choice assays revealed species-specific and sex-specific preferences. In choice assays, Aedes (Ae.) aegypti showed a preference for sweet corn juice (18.1 ± 4.0%), while Ae. albopictus preferred pumpkin juice (19.7 ± 6.0%). Female Ae. aegypti preferred sweet corn (20.2 ± 5.8%) while males preferred honey (19.8 ± 0.8%) most, but both male (22.5 ± 7.3%) and female (19.0 ± 6.8%) Ae. albopictus preferred the pumpkin most. In contrast, Cx. quinquefasciatus favored beetroot juice (17.1 ± 3.6%), and An. quadrimaculatus preferred beetroot (20.8 ± 17.4%) and peach juices (20.1 ± 9.7%). Olfactometer assays for female Ae. aegypti showed enhanced attractiveness with the addition of 3% biogents lure to beetroot juice (61.5 ± 6.5%) compared to beetroot juice (38.9 ± 6.5%) alone. Mortality bioassays confirmed the efficacy of attractive toxic sugar baits formulations containing biogents lure, boric acid, and fruit juices, achieving 86.7% to 100% mortality in all 4 mosquito species within 48 h. While these findings underscore the potential of combining natural and synthetic attractants for mosquito control; the study's laboratory setting and lack of field validation necessitate further research to ensure ecological safety and real-world applicability.

The succession of mosquito species and abiotic factors affecting their distribution and abundance in rice (Oryza spp.) fields was investigated over a 16-wk rice growing cycle covering the period between January and May 2006. Fifteen experimental rice plots were sampled for mosquito larvae and characterized based on rice height, number of tillers, floating vegetation cover, water depth, water temperature, turbidity, salinity, pH, dissolved oxygen, total dissolved solids, and conductivity. Microscopic identification of 3,025 larvae yielded nine mosquito species predominated by Anopheles arabiensis Patton (45.0%), Culex quinquefasciatus Say (35.8%), Anopheles pharoensis Theobald (9.0%) and Ficalbia splendens Theobald (7.1%). Other species, including Anopheles rufipes Gough, Anopheles coustani Laveran, Anonopheles maculipalpis Giles, Culex annulioris Theobald, and Culex poicilipes Theobald made up 3.1% of the total collection. Anopheles gambiae s.l., Cx. quinquefasciatus, and An. pharoensis occurred throughout the cycle, but they were more abundant up to 4 wk posttransplanting with peaks after fertilizer application. As rice plants became established, three groups of mosquitoes were recognized: the first groups included An. rufipes, Fl. splendens, and Cx. annulioris, which occurred throughout much of the second half of the rice cycle, whereas the second group included Cx. poicilipes, which was found in the middle of the rice cycle. An. coustani and An. maculipalpis formed the third group occurring toward the end of the cycle. Dissolved oxygen, number of tillers, and rice height were negatively associated with the abundance ofAn. arabiensis and Cx. quinquefasciatus larvae. In addition, Cx. quinquefasciatus also was associated with water depth (-ve) and turbidity (+ve). Abundance of An. pharoensis larvae was significantly associated with water temperature (+ve), the number of tillers (-ve), and rice height (-ve), whereas Fl. splendens was significantly associated with the number of tillers (+ve). The results demonstrate a complex nature of the interactions between some of the factors in the ecosystem and mosquito species abundance and calls for time-dependent and species-specific mosquito control operations.

The aim of this was to evaluate the larvicidal activity of plant powders of Bauhinia variegata and Croton sparsiflorus against the fourth instar larvae of Aedes albopictus L., Anopheles stephensi L., and Culex quinquefasciatus Say. Derivatives of plants are enriched with active molecules with exceptional mosquitocidal properties and can be advanced as low cost environmentally friendly bio pesticides. The macerated leaf powders of B. variegata and C. sparsiflorus were tested against different mosquito species up to 24 h exposure period with the concentrations of 100, 120, 140, 160, 180, and 200 mg/100 mL of tapwater. The LC50 value of C. sparsiflorus leaf powder exhibited 136.43, 150.53 and 163.74 mg/100 mL against A. albopictus, A. stephensi, and C. quinquefasciatus Say respectively. The B. variegata leaf powder exhibited the LC50 value of 133.27, 124.99 and 135.34 mg/100 mL against A. albopictus, A. stephensi, and C. quinquefasciatus Say respectively. The present investigation clearly demonstrates that C. sparsiflorus showed cent percent mortality followed by B. variegata against different mosquito species. With further isolation and identification of bioactive molecules from B. variegata and C. sparsiflorus can be evaluated and developed novel bio pesticide against mosquitoes as well as other insect pests.

Background & objectives:Different formulations of Bacillus thuringiensis var. israelensis (Bti) have been tested against different mosquito vectors and other insects for their residual activity. In the present study, the efficacy and residual activity of a new formulation of Bti (Bactivec Suspension Concentrate) were evaluated against immature stages of Anopheles stephensi Liston (Diptera: Culicidae), Aedes aegypti Linnaeus (Diptera: Culicidae) and Culex quinquefasciatus Say (Diptera: Culicidae), in natural habitats in Phase II and Phase III in Bengaluru, India.Methods:Preferential breeding habitats of the mosquito species were selected and four dosages (0.25, 0.5, 1 and 2 ml/50 l) were tested in Phase II trial. Two most effective dosages, 0.5 and 1 ml/50 l were selected for Phase III trial. The evaluation was carried out essentially following the guidelines of the World Health Organization Pesticide Evaluation Scheme. Pre-treatment and post-treatment densities were recorded at regular intervals, and >80 per cent reduction in pupae was taken as the duration of effectiveness.Results:Bactivec SC treated at the dosage of 1 ml/50 l could produce 10-17 days efficacy (>80% reduction in pupae) in clean water habitats tested, whereas 0.5 ml/50 l dosage showed residual activity from 7 to 14 days against Ae. aegypti and An. stephensi in Phase III studies. In polluted water habitats, 4-7 days efficacy could be recorded against Cx. quinquefasciatus in Phase III.Interpretation & conclusions:The Bactivec SC formulation was operationally feasible and easy to handle. For the control of Anopheles and Aedes mosquitoes in freshwater habitats, 1 ml/50 l dosage was found effective, whereas in polluted water habitats against Cx. quinquefasciatus 5 ml/m2 was found effective.

A laboratory assessment of desiccation tolerance in larval stages of mosquitoes Anopheles stephensi Liston, 1901 (Diptera: Culicidae) and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) was carried out using five temperature levels and three levels of exposure duration as explanatory variables. The increase in the duration of exposure to desiccation from 15 min to 60 min was noted to result in a substantial increase in water loss (in mg) in mosquito larvae. Similarly, the increase in temperature levels was observed to cause larval mortality and a substantial decrease in the emergence of adults. Both the temperature and the duration of exposure to desiccation were found to be influential factors in determining survival and subsequent emergence of adults. Desiccation is a primary factor in determining the survival of mosquito larvae, particularly in the conditions where habitat permanence is uncertain, e.g., in temporary pools and containers serving as mosquito larval habitats. The results of the present study provide a glimpse into the effects of desiccation at varied temperatures and exposure durations on the successful emergence of adults in mosquitoes Cx. quinquefasciatus and An. stephensi. Although primary, the obtained results show that desiccation can be a probable way of regulating the development of mosquito larvae in conditions where the permanence of the habitat for mosquito larvae is uncertain. Further studies on desiccation tolerance may be carried out using different mosquito species that are adapted to temporary pools and containers as sources for breeding.

The CH2Cl2-MeOH (30:70 v/v) extracts of the seeds of Mangifera indica (Mango), Persea americana (Avocado) and Dacryodes edulis (African plum) were evaluated for potential mosquito larvicidal activity against 3rd and 4th instar larvae of Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae. Extracts were diluted with 1 mL of methanol and concentrations ranging from 1000 to 125 mg/L in 4 replicates each, were prepared in the volume of 100 mL in the plastic cups (250 mL). A volume of 1 mL of methanol added to 99 mL of tap water was prepared as negative control and Bi-one (1000 mg/L) constituted a positive control. In each test solution, 25 larvae of each mosquito species were separately transferred and larval mortality was recorded after 24 h post-treatment. As results, the three plant seed extracts applied at 1000 mg/L caused for at least 79% mortality of each mosquito species larvae assessed. The seed extract of P. americana (LC50 of 98.31, 129.24 and 136.26 mg/L, respectively against An. gambiae, Ae. aegypti and Cx. quiquefasciatus larvae) was the most potent followed by D. edulis (LC50 of 176.87 mg/L for An. gambiae, 198.68 mg/L for Ae. aegypti and 201.70 mg/L for Cx. quinquefasciatus) and M. indica (LC50 of 258.98 mg/L for An. gambiae, 297.35 mg/L for Ae. aegypti and 435.45 mg/L for Cx. quinquefasciatus). Globally, all the seed extracts were more toxic against An. gambiae larvae compared to other mosquito species and need further exploration for the development of a new botanical larvicide to reduce mosquito densities.

O objetivo deste trabalho foi selecionar entre 300 estirpes de Bacillus thuringiensis as efetivas simultaneamente contra larvas de Spodoptera frugiperda J.E. Smith e Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), Anthonomus grandis Boheman (Coleoptera: Curculionidae), Aedes aegypti Linnaeus e Culex quinquefasciatus Say (Diptera: Culicidae). Foram selecionadas duas estirpes de B. thuringiensis, denominadas S234 e S997, que apresentaram atividade contra as três ordens de insetos. As estirpes foram caracterizadas por métodos morfológicos, bioquímicos e moleculares. As mesmas apresentaram duas proteínas principais de 130 e 65 kDa, produtos de reação em cadeia da polimerase de tamanho esperado para a detecção dos genes cry1Aa, cry1Ab, cry1Ac, cry1B e cry2 e cristais bipiramidais, cubóides e esféricos.