Ammonia as an Attractive Component of Host Odour for the Yellow Fever Mosquito, Aedes aegypti

Abstract

Behavioural responses of Aedes aegypti mosquitoes to ammonia were investigated in a modified Y-tube olfactometer. Ammonia was attractive in concentrations from 17 ppb to 17 ppm in air when presented together with lactic acid. Aqueous solutions of ammonia salts in concentrations comparable to those found in human sweat also increased the attractiveness of lactic acid. The role of lactic acid as an essential synergist for ammonia became further apparent by the fact that ammonia alone or in combination with carbon dioxide was not effective, even though the synergistic effect of carbon dioxide and lactic acid was corroborated. An extract from human skin residues, which attracts approximately 80% of the tested mosquitoes, contains both lactic acid and ammonia. The combination of these compounds, however, attracts no more than 45%, indicating that other components on human skin also play a role in host finding. Preparative liquid chromatography of the skin extract yielded three behaviourally active fractions which work together synergistically. Fraction III contains lactic acid as the effective principle; the compositions of the other two have not been clarified yet. The attractiveness of fraction I was augmented considerably when ammonia was added, whereas the effect of fraction II was not influenced by ammonia. These results suggests that ammonia is part of the effective principle of fraction II and contributes to the attractive effect of host odours.

Attraction of the tropical bont tick, Amblyomma variegatum , to human breath and to the breath components acetone, NO and CO 2

“…Displacements of the ticks were sampled every 0.2 s and a running mean over five vectors was applied at 40 s intervals for graphical representation. Note the increased walking speed in the presence of breath (observed in half of the ticks presented with this stimulus), the contrastingly lower speed in response to acetone and NO, and the unchanged speed in the presence of CO 2 may be that presentation of NH 3 with other chemicals is necessary in order to elicit a behavioural response in A. variegatum, as shown by Geier et al (1999) for mosquitoes.…”

The impact of CO2 on collection of Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say by BG-Sentinel(r) traps in Manaus, Brazil

“…The BGL contains substances that are found on human skin, such as ammonia, lactic acid and caproic acid that also attracts for host seeking females Ae. aegypti (Geier et al 1999, Bosch et al 2000.…”

Água de abastecimento público de consumo humano e oviposição de Aedes aegypti

“…This factor is important, not just in increasing the chances of survival, but also in guaranteeing the emergence of a large number of adults. 3,5 Geier et al 15 (1999) showed in a laboratory, that ammonium nitrate is a chemical component which attracts the Aedes aegypti mosquito to their host. That females are attracted to nitrogenous compounds, was also verifi ed by Sunish et al 19 (2003) in egg laying by the Japanese encephalitis vector Culex tritaeniorhynchus.…”