Innate preference for host-odor blends modulates degree of anthropophagy of Anopheles gambiae sensu lato (Diptera: Culicidae)

In field studies, Anopheles gambiae Giles sensu stricto obtains most blood meals from humans, whereas Anopheles quadriannulatus Theobald bites predominantly bovids. We investigated whether host odors modulate the host preference of these mosquito species. In a dual-choice olfactometer, mosquitoes were given a choice between clean air and putative host-specific odor blends. An. gambiae chose ‘human odor’ over clean air and clean air over ‘cow odor.’ Although Anopheles quadriannulatus did not choose cow odor over clean air, it chose clean air over human odor. Cheese odor, which attracted An. gambiae, did not result in higher trap catch of An. quadriannulatus. We conclude that the degree of anthropophagy of An. gambiae s.l. has an innate olfactory basis

Hoe een modelleur een mug vangt - het nut van wiskundige modellen voor het bestuderen en bestrijden van vector-overgedragen ziekten

Vector-overgedragen ziekten zijn infectieziekten die worden overgedragen door vectoren, meestal anthropoden, zoals muggen, knutten en teken. De laatste jaren is de aandacht voor deze ziekten toegenomen. Aanleidingen hiervoor zijn bijvoorbeeld de uitbraak van het West-Nijlvirus in Noord-Amerika, de recente blauwtong-epidemie in Nederland en omringende landen en de uitbraak van chikungunya in Italië

The response of the malaria mosquito, Anopheles gambiae, to two components of human sweat, ammonia and L-lactic acid, in an olfactometer

In an olfactometer study on the response of the anthropophilic malaria mosquito Anopheles gambiae s.s. (Diptera, Culicidae) to human sweat it was found that freshly collected sweat, mostly of eccrine origin, was attractive, but that incubated sweat was significantly more attractive than fresh sweat. The behavioural response to l-lactic acid and ammonia, the main constituents of sweat, was investigated. l-lactic acid was attractive at one concentration only (11.11 mm) and removal of the l-lactic acid from the sweat by enzymatic decomposition did not affect the attractiveness of sweat. Ammonia caused attraction over a range of 0.113.4 m on glass slides and at 0.848.40 mol/min in an air stream. It is concluded that: human sweat contains kairomones for host-seeking An. gambiae; ammonia is an important kairomone for this mosquito; and that l-lactic acid is not a prerequisite in the attraction of An. gambiae to sweat

Comparision of carbon dioxide-baited trapping systems for sampling outdoor mosquito populations in Tanzania

For collecting mosquitoes (Diptera: Culicidae) the outdoor catching efficiency of four types of trapping devices baited with carbon dioxide (CO2, 300 ml/min) was evaluated and compared in two areas of Tanzania. The types of traps employed were: the CDC miniature trap with the incandescent light bulb switched on or off; electric nets (ENT) and a Counterflow Geometry (CFG) trap. In Njage, south-east Tanzania, Anopheles gambiae Giles sensu stricto was the most abundant of the seven mosquito species obtained, comprising of 74.3 f the total number caught (n = 2171). In Muheza, north-east Tanzania, Culex quinquefasciatus Say was the predominant species (90.9€among 1080 caught. At both localities the CFG trap was superior to the CDC trap with light-on or light-off for sampling both An. gambiae and Cx. quinquefasciatus. Efficiency of the CFG trap and ENT were similar for sampling these species of mosquitoes (P > 0.05). However, ENT was superior to the CDC trap with light-off for collecting both species. Significantly more (P < 0.05) Cx. quinquefasciatus were obtained by the CDC trap with light-off than with light-on, especially outdoors. It is concluded that both ENT and the CFG are effective tools for sampling populations of An. gambiae and Cx. quinquefasciatus outdoors

A resource-based habitat concept for tick-borne diseases

Because tick and tick-borne disease distributions are so tightly linked to the environment, a robust conceptual background is necessary to build useful empirical and process-based models and to interpret results coherently with pathogen, vector and host ecology. This is especially pressing when considering that tick-borne pathogen circulation is a complex ecological system that has been studied in a great diversity of ways, producing results that may appear challenging to synthesise. We propose that a resource-based habitat concept can provide helpful leads to collect data, elaborate models and interpret and assemble upcoming and existing results. Two elements in the existing knowledge and its gaps, and in the current ecological context encourage us to explore such a conceptual framework. First, it is rare in the current practice to focus on the ecology of the pathogen, whereas this may be a key element in understanding the role of biodiversity in pathogen circulation. Second, the role of non-classical tick habitats (e.g. forest encroached areas and meadows) is getting more and more often highlighted, indicating that summarising tick habitat, or pathogen habitat, by a single vegetation class is not suitable. We revisit two simulation models (a cellular automata and an agent-based model) that focus on infected ticks and on tick population dynamics. In these models, the potential of a resource-based habitat concept can be highlighted. We then discuss how to implement this concept for studying the ecology of tickborne pathogens