Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience?

Smelly interactions: host-borne volatile organic compounds triggering behavioural responses in mosquitoes, sand flies, and ticks

Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living organisms. These compounds play a key role as olfactory cues for arthropod vectors such as mosquitoes, sand flies, and ticks, which act in the transmission of pathogens to many animal species, including humans. Some VOCs may influence arthropod behaviour, e.g., host preference and oviposition site selection for gravid females. Furthermore, deadly vector-borne pathogens such as Plasmodium falciparum and Leishmania infantum are suggested to manipulate the VOCs profile of the host to make them more attractive to mosquitoes and sand fly vectors, respectively. Under the above circumstances, studies on these compounds have demonstrated their potential usefulness for investigating the behavioural response of mosquitoes, sand flies, and ticks toward their vertebrate hosts, as well as potential tools for diagnosis of vector-borne diseases (VBDs). Herein, we provide an account for scientific data available on VOCs to study the host seeking behaviour of arthropod vectors, and their usefulness as attractants, repellents, or tools for an early diagnosis of VBDs.

nAnopheles blood meal sources and entomological indicators related to Plasmodium transmission in malaria endemic areas of Colombia

Malaria is an important public health problem, caused by Plasmodium parasites which are transmitted by female Anopheles mosquitoes that bite humans to obtain blood. The aim of this work was to identify the blood feeding sources of Anopheles female mosquitoes and calculate their entomological indices in relation to Plasmodium transmission. Mosquitoes were collected in malaria endemic localities of the Bajo Cauca and Pacific regions of Colombia using human landing catch and barrier screens, from 18:00 - 24:00 hr, in 2018-2021. Animal censuses within a radius of ∼250 meters were carried out at each sampling site. A total of 2,018 Anopheles specimens were collected and the most abundant species were Anopheles (Nys.) darlingi and Anopheles (Nys.) nuneztovari. The highest human biting rate was 77.5 bites per person per night (b/p/n) for An. nuneztovari in Córdoba-Pacific and 17.5 b/p/n for An. darlingi in Villa Grande-Bajo Cauca. Both species were active mainly in indoor unwalled rooms of the houses. Only An. nuneztovari from Córdoba-Pacific was infected with Plasmodium, with an entomological inoculation rate of 91.25 infective bites per year. Detection of blood feeding sources demonstrate that humans were the most common host, however, An. nuneztovari showed a preference for feeding on dogs and An. darlingi on pigs, dogs and Galliformes, rather than humans. These results contribute to entomological surveillance information and provide valuable data that can be used to tailor effective control interventions to minimize human-vector contact in these malaria endemic regions.

The Potential Test of the Mosquito Oviposition Preference Using Similar Subtracts: Colonized Water and Aides Larvae Extract

The research on ovitrap using attractants have been extensively developed, but studies on the use of similar substrates in the form of colonized water and Aedes larvae extract as attractants have not been widely published. Adding an attractant to the ovitrap can stimulate the sense of smell for mosquitoes to come to the place to lay their eggs. The use of ovitrap has recently begun to be developed because it is environmentally friendly. The purpose of this study is to determine the attractants potential of colonized water and larvae extract as the oviposition preferences for  of Aedes Sp. to lay eggs in the ovitrap. The type of this research is a true experimental design, the design of The Posttest-Only Control Group Design. Observations are made in the laboratory for nine repetitions. Observational data show that the average number of eggs in ovitraps that uses the colonized water and larvae extract is higher than that of conventional/control water. The results of the Kruskal-Wallis test indicate that there is a significant difference in the average number of eggs in the colonized water attractant, larval extract and conventional water (Asymp. Sig < 0.05). The conclusion is obtained that similar substrate attractants in the form of larvae extract and Aedes colonization water have the potential to be Aedes sp oviposition preferences compared to conventional water. However, it is still necessary to conduct a field study so that it can be used as an environmentally friendly method of the surveillance and control of the vector transmitting Dengue Hemorrhagic Fever.