Attraction of the Mosquitoes Aedes aegypti and Aedes albopictus (Diptera: Culicidae) to a 3-Part Phytochemical Blend in a Mesocosm

Aedes aegypti (L.) and Aedes albopictus (Skuse) mosquitoes of both sexes were attracted to a 3-part volatile synthetic phytochemical blend but differed according to their component ratios, 7:3:2 or 1:1:1, and their initial concentrations. These arbovirus vectors were presented with the blends as baits in paired baited and blank CFG traps in a large greenhouse mesocosm. Ae. aegypti attraction was highest at a 7:3:2 blend ratio, but at a concentration half that found most effective for an anopheline mosquito species in outdoor screenhouses. Both lower and higher concentrations yielded substantially lower attraction scores for Ae. aegypti. By contrast, the few tests conducted on Ae. albopictus showed that it was not as sensitive to concentration, but again it was more responsive to the 7:3:2 ratio of components than to the 1:1:1 ratio. The two sexes of both species were represented equally in the trap catches, indicating the potential value of this and similar attractive blends for population surveillance and control of Aedes mosquitoes.

Immunomodulation by Mosquito Salivary Protein AgSAP Contributes to Early Host Infection by Plasmodium

Malaria is a vector-borne disease caused by Plasmodium sporozoites. When an anopheline mosquito bites its host, it releases Plasmodium sporozoites as well as saliva components.

Updated distribution of anopheline mosquitoes in Hokkaido, Japan, and the first evidence of Anopheles belenrae in Japan

Background In Hokkaido, northern island of Japan, at least seven cases of falciparum malaria were reported by 1951. A survey conducted at that time was unsuccessful in implicating any mosquito species as the possible vector. Although active anopheline mosquito surveillance continued until the middle of the 1980s, there is very limited information on their current status and distribution in Japan. Therefore, this study is an update on the current status and distribution of anopheline mosquitoes in Hokkaido based on a 15-year entomological surveillance between 2001 and 2015. Methods A survey of mosquitoes was conducted at 22 sites in Hokkaido, Japan, from 2001 to 2015. Adult mosquitoes were collected from cowsheds, lakesides, shrubs, and habitats ranging from open grassland to coniferous forest using a Centers for Disease Control and Prevention (CDC) miniature light trap enhanced with dry ice, aspirators, and sweeping nets. Larvae were collected from lakes, ponds, swamps, stagnant and flowing rivers, and paddy fields. All specimens were morphologically identified and subjected to polymerase chain reaction (PCR)-based sequence analysis of the internal transcribed spacer 2 ( ITS2) region of rDNA. Phylogenetic trees were reconstructed using the neighbor-joining method with the Kimura 2-parameter model on MEGA X version 10.2.2. Results A total of 46 anopheline specimens were used for the phylogenetic analysis. During the survey, a new member of the Anopheles hyrcanus group, An. belenrae, was discovered in eastern Hokkaido in 2004. Anopheles belenrae has since then been consistently found and confirmed to inhabit only this area of Japan. Four members of the An. hyrcanus group, namely An. belenrae, An. engarensis, An. lesteri, and An. sineroides, have been found in Hokkaido. The results also suggest that An. sinensis, formerly a dominant species throughout Japan, has become a rarely found species, at least currently in Hokkaido. Conclusion The updated distribution of anopheline mosquitoes in Hokkaido, Japan, showed considerable differences from that observed in previous surveys conducted from 1969 to 1984. In particular, areas where An. sinensis was previously distributed may have been greatly reduced in Hokkaido. The phylogenetic analysis revealed a novel An. hyrcanus group member identified as An. belenrae, described in South Korea in 2005. It is interesting that An. belenrae was confirmed to inhabit only eastern Hokkaido, Japan. Graphical abstract

Updated Distribution of Anopheline Mosquitoes (Diptera: Culicidae) in Hokkaido, Japan, and the First Evidence of Anopheles (Anopheles) Belenrae in Japan

Background: In Hokkaido, northern island of Japan, at least seven cases of falciparum malaria were reported by 1951. A survey conducted at that time was unsuccessful in implicating any mosquito species as the possible vector. Although active anopheline mosquito surveillance continued until the middle of the 1980s, there is very limited information on their current status and distribution in Japan. Therefore, this study is an update on the current status and distribution of anopheline mosquitoes in Hokkaido based on a 15-year entomological surveillance between 2001 and 2015.Methods: A survey of mosquitoes was conducted at 22 sites in Hokkaido, Japan, from 2001 to 2015. Adult mosquitoes were collected from cowsheds, lakesides, shrubs, and habitats ranging from open grassland to coniferous forest using a CDC miniature light trap enhanced with dry ice, aspirators, and sweeping nets. Larvae were collected from lakes, ponds, swamps, stagnant and flowing rivers, and paddy fields. All specimens were morphologically identified and subjected to PCR-based sequence analysis of the ITS2 region of rDNA. Phylogenetic trees were reconstructed using the neighbor-joining method. Results: A total of 46 anopheline specimens were used for the phylogenetic analysis. During the survey, a new member of the Anopheles hyrcanus group, An. belenrae Rueda (2005), was discovered in eastern Hokkaido in 2004. Anopheles belenrae has since then been consistently found and confirmed to inhabit only this area of Japan. Four members of the An. hyrcanus group, An. belenrae, An. engarensis, An. lesteri, and An. sineroides, have been found in Hokkaido. The results also suggest that An. sinensis, formerly a dominant species throughout Japan, has become a rarely found species, at least currently in Hokkaido.Conclusion: The updated distribution of anopheline mosquitoes in Hokkaido, Japan, showed considerable differences from that observed in previous surveys conducted from 1969 to 1984. In particular, areas where An. sinensis was previously distributed may have been greatly reduced in Hokkaido. The phylogenetic analysis revealed a novel An. hyrcanus group member identified as An. belenrae, described in South Korea in 2005. It is interesting that An. belenrae was confirmed to inhabit only eastern Hokkaido, Japan.

Updated Distribution of Anopheline Mosquitoes (Diptera: Culicidae) in Hokkaido, Japan, and The First Evidence of Anopheles (Anopheles) Belenrae in Japan

Background: After World War II in Hokkaido, northern island of Japan, at least seven cases of falciparum malaria were reported by 1951. A survey conducted at that time was unsuccessful in implicating any mosquito species as the possible vector. Although active anopheline mosquito surveillance continued until the middle of the 1980s, there is very limited information on their current status and distribution in Japan. Therefore, this study is an update on the current status and distribution of anopheline mosquitoes in Hokkaido based on a 15-year entomological surveillance between 2001 and 2015. Methods: A survey of mosquitoes was conducted at 22 sites in Hokkaido, Japan, from 2001 to 2015. Adult mosquitoes were collected from cowsheds, lakesides, shrubs, and habitats ranging from open grassland to coniferous forest using a CDC miniature light trap enhanced with dry ice, aspirators, and sweeping nets. Larvae were collected from lakes, ponds, swamps, stagnant and flowing rivers, and paddy fields. All specimens were morphologically identified and subjected to PCR-based sequence analysis of the ITS2 region of rDNA. Phylogenetic trees were reconstructed using the neighbor-joining method. Results: A total of 46 anopheline specimens were used for the phylogenetic analysis. During the survey, a new member of the Anopheles hyrcanus group, An. belenrae Rueda (2005), was discovered in eastern Hokkaido in 2004. A nopheles belenrae has since then been consistently found and confirmed to inhabit only this area of Japan. Four members of the An. h yrcanus group, A n . belenrae , A n . engarensis , A n . lesteri , and An. sineroides , have been found in Hokkaido. The results also suggest that An. sinensis , formerly a dominant species throughout Japan, has become a rarely found species, at least currently in Hokkaido. Conclusion: The updated distribution of anopheline mosquitoes in Hokkaido, Japan, showed considerable differences from that observed in previous surveys conducted from 1969 to 1984. In particular, areas where An. sinensis was previously distributed may have been greatly reduced in Hokkaido. The phylogenetic analysis revealed a novel An. hyrcanus group member identified as An. belenrae , described in South Korea in 2005. It is interesting that An. belenrae was confirmed to inhabit only eastern Hokkaido, Japan.

Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

Background Despite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed to evaluate the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters. Results Overall, 2108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n = 1954) were from irrigated clusters and 7.3% (n = 154) from the non-irrigated. The Anopheles gambiae complex was the most abundant (67.3%) followed by Anopheles coustani complex (25.3%) and Anopheles pharoensis (5.7%). PCR-based identification revealed that 74.7% (n = 168) of the An. gambiae complex were Anopheles arabiensis and 22.7% (n = 51) Anopheles amharicus. The density of An. gambiae complex (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n = 1837) was higher than the dry seasons (12.8%; n = 271). Conclusion The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.

Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

BackgroundDespite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed to evaluate the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors.MethodsAdult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi-square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters.ResultsOverall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1,954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. The Anopheles gambiae complex was the most abundant (67.3%) followed by Anopheles coustani complex (25.3 %) and Anopheles pharoensis (5.7%). PCR-based identification revealed that 74.7% (n=168) of the An. gambiae comlex were Anopheles arabiensis and 22.7% (n=51) Anopheles amharicus. The density of An. gambiae complex (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1,837) was higher than the dry seasons (12.8%; n=271).ConclusionThe ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.