Background Dengue virus (DENV) is a mosquito-borne arbovirus transmitted by Aedes mosquitoes, but is not endemic in all areas where this vector is found. For example, the relatively sparse distribution of cases in West Africa is generally attributed to the refractory nature of West African Aedes aegypti (Ae. aegypti) to DENV infection, and particularly the forest-dwelling Ae. aegypti formosus. However, recent studies have shown these mosquitoes to be competent vectors within some West African countries that have suffered outbreaks in the past, such as Senegal. There is however little information on the vector competence of the Ae. aegypti in West African countries such as Ghana with no reported outbreaks. Methods This study examined the vector competence of 4 Ae. aegypti colonies from urban, semi-urban, and two rural locations in Ghana in transmitting DENV serotypes 1 and 2, using a single colony from Vietnam as control. Midgut infection and virus dissemination were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), while the presence and concentration of DENV in the saliva of infectious mosquitoes was determined by the focus forming assay. Results There were significant differences in the colonies’ susceptibility to virus infection, dissemination, and transmission. All examined Ghanaian mosquitoes were refractory to infection by DENV serotype 2, while some colonies exhibited potential to transmit DENV serotype 1. None of the tested colonies were as competent as the control group colony. Conclusions These findings give insight into the possible risk of outbreaks, particularly in the urban areas in the south of Ghana, and highlight the need for continuous surveillance to determine the transmission status and outbreak risk. This study also highlights the need to prevent importation of different DENV strains and potential invasion of new highly vector-competent Ae. aegypti strains, particularly around the ports of entry. Graphic Abstract

The study aims to make an update on the distribution and ecology of sand flies in the Quang Ninh province, Northern Vietnam, where Leishmania cases were reported in 2001. Seventeen sites were chosen in three districts of the province: Ha Long, Cam Pha, and Hoanh Bo. Phlebotomine sand flies were collected using 68 CDC light traps from May 30 to 3 June 2016. Captured specimens were transferred individually into Eppendorf tubes with 90% ethanol. The sand fly heads and genitalia were removed and were mounted in Euparal after successive different baths. Specimen identification was determined based on the morphology of the cibarium, pharynx, and/or male genitalia or female spermathecae. A total of 416 sand flies (125 females, 283 males) belonging to four genera were collected and 10 sand fly species were identified: Sergentomyia silvatica, Se. barraudi, Se. hivernus, Se. bailyi, Phlebotomus mascomai, Ph. stantoni, Ph. yunshengensis, Ph. betisi, Chinius junlianensis, Idiophlebotomus longiforceps. The Sergentomyia genus prevailed (79.7% of the collected sand flies), followed by the Phlebotomus genus (13.7%), the Chinius genus (6.1%), and the Idiophlebotomus genus (0.8%). Besides these well-defined taxa, five specimens, named sp1, showed unknown morphological characteristics, requiring further study. The majority of sand flies were collected in rock caves suggesting the cavernicolous character of the species in the Quang Ninh province. However, specimens were also collected in intra and peridomiciliary sites in which Ph. stantoni and Se. hivernus were found as the main species. It is worth noting that two Ph. stantoni were found in the house of a patient affected by Leishmania.

This study presents the diversity of mosquitoes collected from communes, endemic with malaria and dengue, located in Khanh Hoa and Binh Phuoc Provinces, Vietnam. A total of 10,288 mosquitoes were collected in the village and forested sites using standard larval dippers, cow-baited traps, ultra-violet light traps, and mechanical aspirators. Mosquito taxa were identified morphologically and species complexes/groups were further characterized molecularly. Five genera of mosquitoes were morphologically identified: Anopheles Meigen (21 species), Aedes Meigen (2 species), Culex Linnaeus (5 species), Mansonia Blanchard sp., and Armigeres Theobald sp. The PCR-based identification methods allowed the distinction of members of Maculatus Group, Funestus Group, and Dirus Complex; and DNA barcodes enabled the further identification of the Barbirostris Complex. Data reported here include the first report of An. saeungae Taai & Harbach and An. wejchoochotei Taai & Harbach from Vietnam, and re-emphasizes the significance of using molecular data in an integrated systematic approach to identify cryptic species and better understand their role in disease transmission.

e attractive baited lethal ovitrap, an autocidal ovitrap, is an alternative tool to control mosquitoes by attracting ovipositing females to lay their eggs in arti cial containers. Ovitrap attracts female mosquitoes by biotic factors, such as larval food and conspeci c larvae. Long-lasting matrix-release formulations containing 2% pyriproxyfen, SumiLarv ® 2MR, are less harmful to the environment and can e ectively reduce targeted mosquitoes for at least six months. We examined the e ects of SumiLarv ® 2MR on attraction of Aedes aegypti (L.) and Ae. albopictus (Skuse) to biotic factors, such as larval food and conspeci c larvae, by two-choice tests. For both species, no signi cant di erence arose between water containing SumiLarv ® 2MR and water alone. Both species laid more eggs in cups with larval food prepared two days before, and the attraction to the food was not a ected by pyriproxyfen. Conspeci c larvae of both species did not show attraction clearly but pyriproxyfen might increase attraction to conspeci cs in Ae. albopictus. SumiLarv ® 2MR did not deter gravid females of both species and did not reduce the e ects of the larval food, suggesting that SumiLarv ® 2MR is a promising formulation for lethal ovitraps.

Public investment is the State’s investment activity to serve the society needs and community benefits. The public investment research has been carried out in terms of the economic sectors, in which public investment funds have effect. By using the statistical method and Hlv(GO), this study evaluated the economic efficiency of investment capital for each economic sector and the economy as a whole. The study found that public investment in Vung Liem district from 2012 to 2016 mainly focused on infrastructure construction, followed by agriculture, but the investment efficiency was not inadequate. On the contrary, the industries - small handicrafts, trades and services have not been properly invested but the investment efficiency was quite high and relatively stable. This is due to the lack of focus on investment resources the, investment process spreading and scattering, not found breakthrough in each sector. This shows that public investment in Vung Liem is effective, but there are many limitations to overcome. Research results are useful references for defining breakthroughs and practical solutions to improve the district’s public investment efficiency