ABSTRACT
Abstract The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses mosquito fauna of Malakand, Pakistan with respect to diversity, relative abundance and distribution in diverse habitats and all seasons of the year. This will assist scientists working in various fields related with epidemiology, medical and veterinary entomology, ecology and allied areas of biological sciences.
Resumo O presente estudo foi conduzido para avaliar a diversidade, distribuição (C) e abundância relativa (RA) da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão. A coleta de espécimes (n = 1087) foi feita durante o período de setembro de 2018 a julho de 2019 em seis habitats diferentes, incluindo corpos d'água, campos de arroz, galpões de animais, ambientes internos, ralos e águas residuais. Os espécimes foram coletados por meio de armadilhas luminosas, spray de piretro, aspiradores e redes e posteriormente mortos, preservados e depois dispostos em caixas entomológicas para identificação. Três gêneros foram identificados, nomeadamente Culex, Anopheles e Aedes. Um total de 14 espécies foi identificado, a saber: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762), An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) e An. annularis (Van der Wulp, 1884). Cx. quinquefasciatus foi encontrado constantemente distribuído na área de estudo com AR = 16,5% e C = 100%. A. annularis foi encontrada como espécie satélite, distribuída esporadicamente na área de estudo com RA = 0,9% e C = 17%. Os índices de diversidade de mosquitos nos habitats estudados foram encontrados como índice de Shannon-Wiener (2,415), índice de Simpson (9,919), índice de Fisher (2,269) e índice de Margalef (1,859). Uma diferença estatisticamente significativa foi registrada na diversidade de mosquitos nos seis habitats (Kruskal-Wallis, qui-quadrado, H = 17,5, df = 5, P = 0,003 em α = 0,05). O presente estudo abrange a fauna de mosquitos de Malakand, Paquistão, com respeito à diversidade, abundância relativa e distribuição em diversos habitats e em todas as estações do ano. Isso ajudará os cientistas que trabalham em vários campos relacionados com a epidemiologia, entomologia médica e veterinária, ecologia e áreas afins das ciências biológicas.
Subject(s)
Animals , Culicidae , Pakistan , Seasons , Ecosystem , EcologyABSTRACT
The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses [...].
O presente estudo foi conduzido para avaliar a diversidade, distribuição (C) e abundância relativa (RA) da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão. A coleta de espécimes (n = 1087) foi feita durante o período de setembro de 2018 a julho de 2019 em seis habitats diferentes, incluindo corpos dágua, campos de arroz, galpões de animais, ambientes internos, ralos e águas residuais. Os espécimes foram coletados por meio de armadilhas luminosas, spray de piretro, aspiradores e redes e posteriormente mortos, preservados e depois dispostos em caixas entomológicas para identificação. Três gêneros foram identificados, nomeadamente Culex, Anopheles e Aedes. Um total de 14 espécies foi identificado, a saber: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762), An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) e An. annularis (Van der Wulp, 1884). Cx. quinquefasciatus foi encontrado constantemente distribuído na área de estudo com AR = 16,5% e C = 100%. A. annularis foi encontrada como espécie satélite, distribuída esporadicamente na área de estudo com RA = 0,9% e C = 17%. Os índices de diversidade de mosquitos nos habitats estudados foram encontrados como índice de Shannon-Wiener (2,415), índice de Simpson (9,919), índice de Fisher (2,269) e índice de Margalef (1,859). Uma diferença estatisticamente significativa foi registrada na diversidade de mosquitos nos seis habitats (Kruskal-Wallis, qui-quadrado, H = 17,5, df = 5, P = 0,003 em α = 0,05). O presente estudo abrange a fauna de mosquitos de Malakand, Paquistão, com respeito à diversidade, abundância relativa e distribuição em [...].
Subject(s)
Animals , Aedes/classification , Anopheles/classification , Biodiversity , Culex/classification , CulicidaeABSTRACT
Abstract The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fishers Index (2.269) and Margalefs Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at = 0.05). The present study encompasses mosquito fauna of Malakand, Pakistan with respect to diversity, relative abundance and distribution in diverse habitats and all seasons of the year. This will assist scientists working in various fields related with epidemiology, medical and veterinary entomology, ecology and allied areas of biological sciences.
Resumo O presente estudo foi conduzido para avaliar a diversidade, distribuição (C) e abundância relativa (RA) da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão. A coleta de espécimes (n = 1087) foi feita durante o período de setembro de 2018 a julho de 2019 em seis habitats diferentes, incluindo corpos dágua, campos de arroz, galpões de animais, ambientes internos, ralos e águas residuais. Os espécimes foram coletados por meio de armadilhas luminosas, spray de piretro, aspiradores e redes e posteriormente mortos, preservados e depois dispostos em caixas entomológicas para identificação. Três gêneros foram identificados, nomeadamente Culex, Anopheles e Aedes. Um total de 14 espécies foi identificado, a saber: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762), An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) e An. annularis (Van der Wulp, 1884). Cx. quinquefasciatus foi encontrado constantemente distribuído na área de estudo com AR = 16,5% e C = 100%. A. annularis foi encontrada como espécie satélite, distribuída esporadicamente na área de estudo com RA = 0,9% e C = 17%. Os índices de diversidade de mosquitos nos habitats estudados foram encontrados como índice de Shannon-Wiener (2,415), índice de Simpson (9,919), índice de Fisher (2,269) e índice de Margalef (1,859). Uma diferença estatisticamente significativa foi registrada na diversidade de mosquitos nos seis habitats (Kruskal-Wallis, qui-quadrado, H = 17,5, df = 5, P = 0,003 em = 0,05). O presente estudo abrange a fauna de mosquitos de Malakand, Paquistão, com respeito à diversidade, abundância relativa e distribuição em diversos habitats e em todas as estações do ano. Isso ajudará os cientistas que trabalham em vários campos relacionados com a epidemiologia, entomologia médica e veterinária, ecologia e áreas afins das ciências biológicas.
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Objective To investigate the infection and genotypes of Wolbachia in common mosquito species in Henan Province, so as to provide insights into management of mosquito-borne diseases. Methods Aedes, Culex and Anopheles samples were collected from cowsheds, sheepfolds and human houses in Puyang, Nanyang City and Xuchang cities of Henan Province from July to September, 2022, and the infection of Wolbachia was detected. The 16S rDNA and wsp genes of Wolbachia were amplified and sequenced. Sequence alignment was performed using the BLAST software, and the obtained 16S rDNA gene sequence was compared with the sequence of the 16S rDNA gene in GenBank database. In addition, the phylogenetic trees were created based on 16S rDNA and wsp gene sequences using the software MEGA 11.0. Results A total 506 female adult mosquitoes were collected from three sampling sites in Nanyang, Xuchang City and Puyang cities from July to September, 2022. The overall detection of Wolbachia was 45.1% (228/506) in mosquitoes, with a higher detection rate in A. albopictus than in Cx. pipiens pallens [97.9% (143/146) vs. 50.6% (85/168); χ2 = 88.064, P < 0.01]. The detection of Wolbachia in Cx. pipiens pallens was higher in Xuchang City (96.8%, 62/64) than in Nanyang (15.6%, 7/45) and Puyang cities (27.1%, 16/59) (χ2 = 89.950, P < 0.01). The homologies of obtained Wolbachia 16S rDNA and wsp gene sequences were 95.3% to 100.0% and 81.7% to 99.8%. Phylogenetic analysis based on wsp gene sequences showed Wolbachia supergroups A and B in mosquito samples, with wAlbA and wMors strains in supergroup A and wPip and wAlbB strains in supergroup B. Wolbachia strain wAlbB infection was detected in A. albopictus in Puyang and Nanyang Cities, while Wolbachia strain wPip infection was identified in A. albopictus in Xuchang City. Wolbachia strain wAlbA infection was detected in Cx. pipiens pallens sampled from three cities, and one Cx. pipiens pallens was found to be infected with Wolbachia strain wMors in Nanyang City. Conclusions Wolbachia infection is commonly prevalent in Ae. albopictus and Cx. pipiens pallens from Henan Province, and Wolbachia strains wAlbB and wAlbA are predominant in Ae. albopictus, while wPip strain is predominant in Cx. pipiens pallens. This is the first report to present Wolbachia wMors strain infection in Cx. pipiens pallens in Henan Province.
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Background and objectives: In America, of the 44 species of Anopheles, nine are main vectors of malaria and, of these, genetic information exists for seven. Hence, this study sought to know the gene flow and diversity of the seven principal vectors of malaria at the Americas level. Methods: For the seven species and the sequences of the mitochondrial cytochrome c oxidase I (COI) gene obtained from the GenBank and Bold System, genetic analyzes of populations and genetic structure were performed and haplotype networks and phylogenetic trees were obtained. Results: For the seven species, 1440 sequences were analyzed and 519 haplotypes were detected. The Hd and ? values were higher within a continental context than by countries. Neutrality tests indicated positive and negative values with most of these being significant (p < 0.05). Phylogenetic analyses for all the species recovered three clades with no geographic pattern among them. Interpretation & conclusion: Studies suggest that native species of Anopheles from the Americas have greater haplotype diversity and low genetic differentiation due to the lack of physical barriers to impede gene flow among these populations. Moreover, all the species are interconnected by roadways. This scenario complicates the epidemiological picture of malaria in the Americas.
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Aims: The study evaluated the repellency effects of some tropical plants and shrubs found in semi- rural communities of Badagry Area of Lagos state; which are acclaimed to have the potentials of repelling mosquitoes from human dwellings. The repellency effects of Moringa oleifera, Morinda lucida, Magnifera indica and Phyllanthus muellerianus to adult Anopheles gambiea was evaluated in the Laboratory. Study Design: The study was carried out at Central Research Laboratory of Lagos State University, Ojo, Lagos, Nigeria and Central Research Laboratory of University of Lagos, Akoka, Lagos, Nigeria. Powdered of dried test plants were prepared and admix with coconut husk as inert, different concentrations were rubbed on the forearm of volunteers and repellency to blood starved female Anopheles mosquitoes was observed. Methodology: Test plants were collected from Badagry area of Lagos State, they were identified at University of Lagos Herbarium and given numbers. They were dried between 10 and 14 days at temperature of 25-27oC and powdered. Different concentrations of the powder mixed with powdered coconut husk was used to treat volunteers forearms and they were exposed to 0-2 two day old adult unfed mosquitoes in an aluminum glass cage fitted with net as arm entrance and repellency was observed for a period of 180 minutes, with landing counts taken every 30 minutes. The test plants were also subjected to qualitative and quantitative phytochemical analysis at University of Lagos Central Research Laboratory. Results: Results showed that all test plants were able to repel Anopheles mosquitoes in the study, repellency was shown in descending order Moringa oleifera with 88%, Magnifera indica 83%, Phyllantus muellerianuss 80% and Morinda lucida 72%. There was no statistical significance in percentage repellency at 95% CL. The result of phytochemical screening of the test plants showed that only M .indica indicated presence of saponing (36.99%). While M.oleifera has highest phenol content (45.6%3), Alkaloid (38.68%), steroid (24.89%) and Tannin (33.19%). Flavonoid and reducing sugar quantity was highest in M. indica (39.39%) and (55.18%) respectively. Conclusion: The plants were able to show repellency to Anopheles gambiae a nuisance malaria vector of serious medical importance. These plants are available in all tropical areas of Africa, they can therefore be used to prevent nuisance and painful mosquito bites which could be a sustainable way to prevent mosquito vectored diseases
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Background & objectives: Bacillus subtilis subsp. subtilis (VCRC B471) and Pseudomonas fluorescens (B426) produce mosquitocidal biosurfactant, surfactin and di-rhamnolipid. The objective of the study was to carry out a small-scale field evaluation of the two biosurfactants to determine the efficacy, application dosage, residual activity and frequency of application against Anopheles stephensi immatures in selected sites in Goa, India. Methods: Surfactin (VCRC B471) and di-rhamnolipid (VCRC B426) were formulated as aqueous suspensions (5% AS), and were applied at the dosages of 34, 51 and 68 mL/m2 and 27, 41 and 54 mL/m2 respectively. Two experiments were carried out with the two formulations. Results: Surfactin (VCRC B471) formulation was effective at all the dosages and there was sustained reduction (>80%) in immature density in the treated sites up to 18 days in experiment 1 and up to 15 days in experiment 2. No pupae were found in the treated sites throughout the study. Di-rhamnolipid (VCRC B426) formulation was also found to reduce the immature density in the treated sites up to 14 days in experiment 1 and up to 15 days in experiment 2. Interpretation & conclusion: For VCRC B471, the optimum application dosage determined was 51 mL/m2 and for VCRC B426, 27mL/m2 . The formulations are to be applied fortnightly for effective control of Anopheles. The application dosage determined in the present study can be used for large scale field evaluation to assess their suitability for use in public health programmes for the control of Anopheles mosquitoes vectoring malaria
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Background & objectives: Malaria remains a public health problem in Côte d’Ivoire. To cope with this issue, the Ministry of Health established strategies through Long-Lasting Insecticidal Nets (LLINs) and artemisinin-based medicines. To better understand the influence of periodic mass distribution of LLINs on malaria transmission, this entomological survey was conducted in three regions of Côte d’Ivoire. Methods: Mosquitoes were sampled by Human Landing Catches (HLC) in urban and rural settings of Korhogo, Man and Abengourou. Mosquitoes were identified morphologically and by molecular methods. Plasmodium falciparum infection was assessed by ELISA, and the Entomological Inoculation Rates (EIR) were calculated for each species and setting. Results: Only An. gambiae s.l. was identified in Korhogo and in Abengourou while An. gambiae s.l. and An. funestus s.l. was reported in Man. An. coluzzii was the most abundant species of the An. gambiae siblings collected in Abengourou, and in Man while An. gambiae was most abundant in Korhogo. In urban settings, malaria vectors showed high aggressiveness (>11 bites per person per night) and the annual EIR was high (83.22-438.44 infectious bites per person per year). In rural settings, malaria vectors showed also high aggressiveness (19-52 b/p/n). The annual EIR is very high (>94 ib/p/yr). However, the weakest EIR was recorded in the northern region with 94.90 ib/p/yr. Interpretation & conclusion: This work indicates that malaria transmission remains high and heterogeneous across Côte d’Ivoire, despite repeated mass distribution of LLINs. Also, in Man, malaria transmission is more intense with the involvement of two main vectors. Furthermore, in the village of Korhogo, the EIR remained relatively low.
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Background: Vector control of Malaria is mainly made by using impregnated bed nets and insecticides pulverizations indoor or/and outdoor. Besides, appearance and development of resistance抯 phenomenon among mosquito populations to insecticides, constitute a significant obstacle this fighting. Aims: To highlighting a neutralization phenomenon of three insecticides (methyl-parathion, dimethoate and cypermethrin) during development of the Anopheles gambiae s.s. larvae. Methodology: Two setups followed one after the other were designed. In setup 1, four concentrations (with four replicates each) were freshly prepared and independently received a first batch of 100 first instars An. gambiae s.s. After emergence of adults from this first batch, the same test media were simply filtered and received a second batch of first instars larvae to make setup 2. Three endpoints were measured in this study: the duration of larval phase, the larval mortality, and the size of adults. Results: The development duration and mortality of larvae decreased significantly at setup 2 with cypermethrin and methyl-parathion. Thus, the duration of larval stage decreased from 10.18 days at setup 1 to 7.84 days at setup 2 for 0.010 礸/l (highest concentration) with cypermethrin and from 10.20 days at setup 1 to 8.27 days at setup 2 for 0.144 礸/l (highest concentration) with methyl-parathion. The larval mortality dropped from 79.32 % at setup 1 to 12.00 % at setup 2 for the highest concentration of cypermethrin and from 76.42 % at setup 1 to 12.50 % at setup 2 for the highest concentration of methyl-parathion. While adults size significantly increased in setup 2. For males, wing抯 length increased from 3.28 mm at setup 1 to 3.49 mm at setup 2 for the highest concentration of cypermethrin, from 3.31 mm at setup 1 to 3.49 mm at setup 2 for the highest concentration of methyl-parathion. In female, wing抯 length increased from 3.52 mm at setup 1 to 3.68 mm at setup 2 for the highest concentration of cypermethrin, from 3.49 mm at setup 1 to 3.68 mm at setup 2 for the highest concentration of methyl-parathion. Conclusion: This work shows that mosquito larvae, especially An. gambiae are able to modify breeding medium to improve its fitness during their development.
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Sardar Sarovar Irrigation Canal system was constructed by Narmada Valley Development Authority (NVDA) to cater to drinking water as well as for irrigation purposes in Jalore and Barmer districts of Western Rajasthan. To cater to the needs of water for the villagers in the command areas, ‘Diggies’ (surface water tanks) with ‘Sumpwells’ (water supply surface tanks) were installed. In a health impact assessment study of the irrigation canals from December 2010 to February 2016, the breeding of two major malaria vectors. An. culicifacies and An. stephensi were observed in diggies and sumpwells. As a biological control, Gambusia affanis fishes were employed for larval control in such stagnated water sites during the intervention phase viz. February 2012 in 251 diggies and 251 sumpwells. A significant reduction of breeding in diggies (99.54%) and sumpwells (97.81%) was observed. The positivity and larval density (dip index) were monitored in the control from up to February 2016 for their sustainability.
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Malaria is a vector borne disease, considered to be one of the most serious public health problems. The present review focused on the blocking of parasite development in mosquito vectors; one broad strategy for achieving this is Transmission Blocking Vaccines (TBV). The TBVs usually rely on immunization of vertebrate hosts with molecules derived from the vector or pathogen to reduce pathogen transmission from infected to uninfected hosts. Most of the studies on the TBVs are based on the antibodies targeted against the surface antigens of sexual stages of malaria parasite, but it is meagre to develop mosquito-based vaccine in this regard. Vector-based TBVs include surface proteins that are expressed by the mosquito midgut digestive enzymes which are induced upon blood-feeding, and receptors expressed on the epithelial line of the tissue. Many proteins are reported that can act as candidates for transmission-blocking vaccines. This review aims to summarize the vector midgut-based proteins identified till date, that can block the development and maturity of sexual stages of the parasite within mosquitoes as targets for transmission-blocking vaccine development. The TBVs intervention can block transmission of different malaria parasite species in various species of mosquitoes with future application perspective worldwide.
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ABSTRACT Background: Malaria is a global health problem and is transmitted by the Anopheles species. Due to the epidemiological importance of the genus, studies on biological, phylogenetic, and evolutionary aspects have contributed to the understanding of adaptation, vector capacity, and resistance to insecticides. The latter may result from different causes such as mutations in the gene that encodes the sodium channel (NaV). Methods: In this study, the NaV subunit I scaffold of 17 anopheline species was used to infer phylogenetic relationships of the genus Anopheles using Bayesian inference. The evolutionary phylogenetic tree of the NaV gene was aligned in the AliView program and analyzed utilizing Bayesian inference, using the software MrBayes. Results: The anophelines were grouped into five well-supported clusters: 1 - Anopheles darlingi and Anopheles albimanus; 2 - Anopheles sinensis and Anopheles atroparvus; 3 - Anopheles dirus; 4 - Anopheles minimus, Anopheles culicifacies, Anopheles funestus, Anopheles maculatus, and Anopheles stephensi; and 5 - Anopheles christyi, Anopheles epiroticus, Anopheles merus, Anopheles melas, Anopheles gambiae, Anopheles coluzzii, and Anopheles arabiensis. Conclusions: The topology confirms the phylogenetic relationships proposed in studies based on the genome of some anophelines and reflects the current taxonomy of the genus, which suggests that NaV undergoes selection pressure during the evolution of the species. These data are useful tools for inferring their ability to resist insecticides and also help in better understanding the evolutionary processes of the genus Anopheles.
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@#Abstract: Objective To understand the kdr (knockdown resistance, kdr) gene mutation of the voltage-gated sodium channel (VGSC) of Anopheles sinensis in Yunnan Province. Methods From 2018 to 2019, mosquitoes were collected in Luoping County, Suijiang County, Tengchong City, Yingjiang County, Yuanjiang County and Mengla County in Yunnan Province. The collected mosquitoes were morphologically identified as Anopheles sinensis and genomic DNA was extracted by kits. The DNA templates were sequenced after PCR amplification and the sequencing results were identify as Anopheles sinensis by homology alignment in NCBI. After the ⅡS5 and ⅡS6 fragments of the sodium channels in Anopheles sinensis were amplified and sequenced, the sequencing results were multiple aligned by DNAMAN software, and the mutations were analyzed one by one with BioEdit software to determine the kdr allele types and genotypes, and the frequencies were calculated. Results This survey amplified 287 sequences, and the sequence maps showed that 1014 loci had three alleles, including wild type TTG/L (89.20%), mutant type TTT/F (9.76%) and TCG/S (1.04%). Five genotypes: homozygous wildtype L/L (85.02%), homozygous mutant F/F (6.27%) and S/S (0.35%), heterozygous mutant L/F (6.97%) and L/S (1.39%). The wild type allele TTG/L was the main allele in six sampling sites except Suijiang County. The frequency of wild type allele in Tengchong City was the highest (100.00%). That is, no mutation was detected, while the rest of counties occurred different degrees of mutation at 1014 loci. The frequency of mutant allele in Suijiang County was the highest, reaching 55.68%. Luoping County, Mengla County and Suijiang County had two mutant types. Yingjiang County and Yuanjiang County had one heterozygous mutant L/F. Conclusion Wild type L1014 (TTG/L) is still dominant in most areas of Yunnan Province. The kdr mutation type is mainly L1014F, followed by L1014S, and the mutation frequency is lower than that in central provinces of China.
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Malaria caused a heavy disease, economic and social burdens in China. Following 70-year concerted efforts, China has been awarded a malaria-free certification by the WHO on June 2021. This paper summarizes the control strategies of Anopheles vectors from malaria control to post-elimination stages in China, emphasizes the risk of imported malaria cases caused re-transmission and the challenges of Anopheles control after malaria elimination in China. Sustainable and precise vector control is still required in China during the post-elimination stage to consolidate malaria elimination achievements in the country. In addition, China’s innovative vector control strategies, technologies and experiences will contribute to global malaria control and elimination programs.
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Objective To investigate the effects of nitroquine on the development of different stages of Plasmodium yoelii in Anopheles stephensi. Methods An. stephensi mosquitoes were fed with conventional sucrose water or sucrose water containing 100 μmol/L nitroquine one day prior to P. yoelii infection. Following starvation for 24 hours, mosquitoes were fed with the blood of Kunming mice infected with P. yoelii, and the number of oocysts was observed in the stomach of An. stephensi. After 6 days and 14 days of infection, the mosquitoes were starved for 24 hours, and then fed with conventional sucrose water or nitroquine treated sucrose water. The An. stephensi mosquitoes were starved for 24 hours 6 and 14 days post-infection with P. yoelii, and then fed with conventional sucrose water or nitroquine-containing sucrose water, the numbers of P. yoelii sporozoites were examined in the hemolymph and salivary glands of An. stephensi. Results Following exposure to nitroquine-containing sucrose water one day prior to P. yoelii infections, the number of P. yoelii oocysts was significantly lower in the An. stephensi stomach on day 7 (119.2 ± 16.1 vs. 207.3 ± 21.8; t = 3.207, P < 0.05). After conventional sucrose water was ceased for 24 hours on day 6, and An. stephensi was fed with nitroquine-containing sucrose water, the number of P. yoelii sporozoites peaked in the hemolymph on day 14 in the nitroquine treatment group (952.3 ± 22.7) and on day 12 in the sucrose water treatment group (1 287.0 ± 39.0), and there was a significant difference in the number of sporozoites in the salivary glands between the nitroquine treatment group and the sucrose water treatment group (9 467.0 ± 1 304.0 vs. 10 533.0 ± 758.7; t = 0.707, P = 0.506) on day 17. After conventional sucrose water was ceased for 24 hours on day 14, and An. stephensi was fed with nitroquine-containing sucrose water, the number of sporozoites in the salivary glands was significantly greater in the nitroquine treatment group than in the sucrose water treatment group (21 900.0 ± 2 613.0 vs. 10 533.0 ± 732.3; t = 4.188, P < 0.05). Conclusions Nitroquine treatment exhibits diverse effects the development of different stages of P. yoelii, and nitroquine treatment may reduce the transmission of P. yoelii in uninfected An. stephensi.
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ABSTRACT Background: To analyze the epidemiological behavior of malaria, in relation to armed conflicts presented on the Pacific coast of Nariño (PCN). Methodology: There was a multi-group ecological study with secondary information source, the frequency of malaria in the (PCN) population, and the relationship with armed conflicts in the region, resulting from the country's internal conflict, from 2003 to 2017, was analyzed. Results: Armed conflict affects the structure of healthcare services for both, the general population and malaria sufferers. The most common affections were to the infrastructure, reduction in the number of healthcare personnel, conservation of vaccines and medicines, access to health care, the inability to do preventive activities and the poor presence of the government in the PCN area. Moreover, the displacement of the population to areas where the vector abounds increases the probability to get sick. Conclusions: This study found an inversely proportional relationship between the frequency of malaria cases and armed conflict. This situation could show that maybe the "conflict" controls malaria. However, it is important to clarify that it could be only masking the reality of the PCN, because the situation that this region was facing stopped the population from accessing the malaria prevention programs and health services, making it difficult to diagnose, treat, and notify the public health surveillance systems. These aspects could contribute to a case reduction during the armed conflict period.
RESUMEN Antecedentes: Analizar el comportamiento epidemiológico de la malaria en relación con los conflictos armados presentados en la costa Pacífica del Departamento de Nariño (CPN). Metodología: Estudio ecológico multigrupo con fuente de información secundaria, se analizó la frecuencia de malaria en la población (CPN) y la relación con los conflictos armados en la región, como resultado del conflicto interno del país durante 2003 a 2017. Resultados: El conflicto armado afecta la estructura de los servicios de salud que atienden a la población en general y a los enfermos de malaria. Las afecciones más comunes fueron la infraestructura, la reducción en el número de personal de salud, la conservación de vacunas y medicamentos, el acceso a la atención médica, la incapacidad para realizar actividades preventivas y la escasa presencia del gobierno en el área de CPN. Además, el desplazamiento de la población a áreas donde abunda el vector aumenta la probabilidad de enfermarse. Conclusiones: Este estudio encontró una relación inversamente proporcional entre la frecuencia de los casos de malaria y los conflictos armados. Esta situación podría mostrar que tal vez el "conflicto" controla la malaria. Sin embargo, es importante aclarar que podría ser solo un enmascaramiento de la realidad de la CPN, porque la situación que enfrentaba esta región hizo que la población no pudiera acceder a los programas y servicios de salud de la Malaria, dificultando el diagnóstico, el tratamiento y la notificación a los sistemas de vigilancia en salud pública. Estos aspectos podrían contribuir a la reducción de casos durante el período de conflicto armado.
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Se evaluó la eficiencia de la trampa Mosquito Magnet Liberty PlusTM (MMLP) cebada con los atrayentes químicos 1-octen-3-ol (octenol) y Lurex 3TM (L-ácido láctico) junto con dióxido de carbono (CO2) para recolectar anofelinos en la localidad Ye'kwana de Boca de Nichare, municipio Sucre, estado Bolívar, Venezuela. La trampa fue operada entre las 18:00 y 06:00 horas, durante 10 noches por mes, durante cuatro meses (Julio Octubre, 2015), alternándose cada noche el atrayente. A fin de caracterizar la actividad nocturna de los anofelinos, cada cuatro horas se cambiaba la jaulita donde eran atrapados los mosquitos. Se capturaron cinco especies de Anopheles y cuatro de Culicinae, siendo las más abundantes, Anopheles (Nyssorhynchus) darlingi Root y Anopheles (Nyssorhynchus) oswaldoi (Peryassú) sensu lato. El ANOVA factorial no paramétrico de Transformación de Rangos Alineados para la variable atrayente y sus interacciones con especie e intervalo horario no fueron estadísticamente significativas (p > 0.05). Estas especies muestran comportamientos diferentes: An. darlingi tiene el pico de actividad nocturna entre las 22:00 y 02:00 horas, mientras que en An. oswaldoi s.l. se observa un incremento de la actividad nocturna progresivamente que se mantiene durante el intervalo 02:00-06:00 horas. Los resultados permiten concluir que la trampa MMLP cebada con octenol o Lurex es un método alternativo de recolección de mosquitos para la vigilancia entomológica en áreas maláricas remotas con población indígena. La actividad horaria de los vectores An. darlingi y An. oswaldoi s.l. sugiere que el uso de mosquiteros tratados con insecticidas puede resultar un método efectivo para el control de la transmisión de malaria en esta zona del país(AU)
The efficiency of the Mosquito Magnet Liberty PlusTM (MMLP) trap was evaluated baited with the chemical attractants 1-octen-3-ol (octenol) and Lurex3M (L-lactic acid) together with carbon dioxide (CO2) to collect anophelines in the Amerindian village Boca de Nichare, Sucre municipality, Bolívar State, Venezuela. The trap was operated between 18:00 and 06: hours, 10 nights per month for four months (July-October 2015), the attractants were alternated nightly. To determine the host seeking behavior of anophelines, the trap cage was changed every 4 hours. Five species of Anopheles and four of Culicinae were collected; Anopheles (Nyssorhynchus) darlingi Root and Anopheles oswaldoi (Peryassú) sensu lato were the most abundant species collected. The Align Rank Transform (ART) test for nonparametric ANOVA for the variable attractant and its interactions with species and hour interval were not significant (p > 0.05). An. darlingi and An. oswaldoi s.l. showed contrasting host seeking activity: An. darlingi showed a peak between 22:00 and 02:00 hours, while in An. oswaldoi s.l. there was a steady increase in activity up to the interval 02:00-06:00 hours. The MMLP trap baited either with octenol or Lurex is an alternative method for entomological surveillance in remote Amerindian malaria endemic areas. The biting activity of the vectors An. darlingi and An. oswaldoi s.l. suggests that the use of long-lasting insecticide treated nets could be an effective method to control the transmission of malaria in this area(AU)
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Animals , Venezuela , Indigenous Peoples , Environmental Health , Public HealthABSTRACT
Unforeseen Plasmodium infections in the Atlantic Forest of Brazilian Extra-Amazonian region could jeopardise malaria elimination. A human malaria case was registered in Três Forquilhas, in the Atlantic Forest biome of Rio Grande do Sul, after a 45 years' time-lapsed without any malaria autochthonous notification in this southern Brazilian state. This finding represents the expansion of the malaria distribution areas in Brazil and the southernmost human malaria case record in South America in this decade. The coexistence of the bromeliad-breeding vector Anopheles (Kerteszia) cruzii and non-human primates in the Atlantic Forest regularly visited by the patient claimed for the zoonotic origin of this infection. The reemergence of Atlantic Forest human malaria in Rio Grande do Sul was also discussed.
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Animals , Malaria/epidemiology , Anopheles , Brazil/epidemiology , Forests , Mosquito VectorsABSTRACT
Objective To analyze the changes of small molecular metabolites in the larvae of a deltamethrin-sensitive strain of Anopheles sinensis following exposure to deltamethrin, so as to provide the scientific basis for investigating the metabolic pathway and screening metabolic markers of deltamethrin in An. sinensis. Methods The 50% and 75% lethal concentrations (LC50 and LC75) of deltamethrin against the larvae of a deltamethrin-sensitive strain of An. sinensis were calculated in laboratory. The type and content of An. sinensis larvae metabolites were detected using high performance liquid chromatography and mass spectrometry (LC-MS/MS) following exposure to deltamethrin at LC50 and LC75 for 30 min and 24 h, and the changes of metabolites were analyzed. Results The LC50 and LC75 values of deltamethrin were 4.36 × 10-3 µg/mL and 1.12 × 10-2 µg/mL against thelarvae of a deltamethrin-sensitive strain of An. sinensis. Following exposure of the larvae of a deltamethrin-sensitive strain of An. sinensis to deltamethrin at LC50 and LC75 for 30 min, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, fatty acyl and pyrimidine nucleotides, with reduced glucose levels. Following exposure for 24 h, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, aliphatic acyl and purine nucleotides, with increased glucose level detected. Conclusion Carbohydrate, carboxylic acid and its derivatives, fatty acyls, amino acids and their derivatives may play important roles in deltamethrin metabolism in the larvae of a deltamethrin-sensitive strain of An. sinensis.
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Objective To investigate the susceptibility of Anopheles sinensis to malathion, deltamethrin and lambda-cyhalothrin in Puyang City, Henan Province, so as to provide the scientific basis for local malaria vector control. Methods An. sinensis was captured from Puyang County, Puyang City of Henan Province in September 2018 and July 2020, and the susceptibility of field captured An. sinensis to malathion, deltamethrin and lambda-cyhalothrin was tested using the filter-paper bioassay recommended by WHO. The insecticide resistance level was assessed based on the WHO criteria. Results In 2018 and 2010, the half knock-down times (KT50) of malathion were 91.08 min and 40.95 min for An. sinensis, with knock-down rates of 37.50% and 60.87% 60 min post-exposure to malathion and 24-hour mortality rates of 90.91% and 100%, respectively, and the insecticide resistance levels were moderately resistant (M) and susceptible (S). The KT50 of deltamethrin were 415.56 min and 341.19 min for An. sinensis in 2018 and 2020, with knock-down rates of 22.92% and 16.98% 60 min post-exposure to malathion and 24-hour mortality rates of 22.92% and 16.98%, and the insecticide resistance levels were all resistant (R). The KT50 of lambda-cyhalothrin were 164.22 min and 236.22 min for An. sinensis in 2018 and 2020, with knock-down rates of 30.39% and 38.30% 60 min postexposure to malathion and 24 h mortality rates of 19.60% and 21.28%, respectively, and the insecticide resistance levels were all R. Conclusion An. sinensis is relatively susceptible to malathion but has developed high-level resistance to deltamethrin and lambda-cyhalothrin in Puyang City, Henan Province..