A new study — about malaria-causing mosquitos and stinky human feet — builds on the Ig Nobel Prize-winning experiments performed by Bart Knols and Ruurd de Jong. Knols and de Jong also showed that the mosquitoes are attracted to the smell of limburger cheese. [Knols described that research publicly again last week at the Ig Nobel show at the University of Geneva.]
The new study is:
“Malaria Infected Mosquitoes Express Enhanced Attraction to Human Odor,” Renate C. Smallegange, Geert-Jan van Gemert, Marga van de Vegte-Bolmer, Salvador Gezan, Willem Takken, Robert W. Sauerwein, James G. Logan [pictured here], PLoS ONE, 8(5): 2013, e63602.
“There is much evidence that some pathogens manipulate the behaviour of their mosquito hosts to enhance pathogen transmission. However, it is unknown whether this phenomenon exists in the interaction of Anopheles gambiae sensu stricto with the malaria parasite, Plasmodium falciparum – one of the most important interactions in the context of humanity, with malaria causing over 200 million human cases and over 770 thousand deaths each year. Here we demonstrate, for the first time, that infection with P. falciparum causes alterations in behavioural responses to host-derived olfactory stimuli in host-seeking female An. gambiae s.s. mosquitoes. In behavioural experiments we showed that P. falciparum-infected An. gambiae mosquitoes were significantly more attracted to human odors than uninfected mosquitoes…
“Considering the high degree of anthropophily of An. gambiae s.s. females and the practical and effective use of human foot odor in vitro, human foot odor was collected on a nylon matrix as described previously (20 Den panty sock, HEMA, The Netherlands, worn during 20 hours prior to the day on which the bioassay was performed by a male volunteer of whom the relative attractiveness to An. gambiae s.s. compared to 47 other men is known).”
The 2006 Ig Nobel Prize for entomology was awarded to Bart Knols (of Wageningen Agricultural University, in Wageningen, the Netherlands; and of the National Institute for Medical Research, in Ifakara Centre, Tanzania, and of the International Atomic Energy Agency, in Vienna Austria) and Ruurd de Jong (of Wageningen Agricultural University and of Santa Maria degli Angeli, Italy) for showing that the female malaria mosquito Anopheles gambiae is attracted equally to the smell of limburger cheese and to the smell of human feet. That work included:
- “On Human Odour, Malaria Mosquitoes, and Limburger Cheese,” Bart. G.J. Knols, The Lancet, vol. 348 , November 9, 1996, p. 1322.
- “Behavioural and electrophysiological responses of the female malaria mosquito Anopheles gambiae (Diptera: Culicidae) to Limburger cheese volatiles,” Bulletin of Entomological Research, B.G.J. Knols, J.J.A. van Loon, A. Cork, R.D. Robinson, et al., vol. 87, 1997, pp. 151-159.
- “Limburger Cheese as an Attractant for the Malaria Mosquito Anopheles gambiae s.s.,” B.G,J. Knols and R. De Jong, Parasitology Today, vol. 12, no. 4, 1996, pp. 159-61.
- “Selection of Biting Sites on Man by Two Malaria Mosquito Species,” R. De Jong and B.G.J. Knols, Experientia, vol. 51, 1995, pp. 80–84
Much of the reportage and commentary about this has not explicitly mentioned the earlier experiments. See, for example the BBC’s “Malaria parasite lures mosquito to human odour” and ScienceNow’s “Stinky Feet Smell Sweet to Malaria-Infected Mosquitoes“.
(Thanks to investigator Neil Judell for bringing this to our attention.)
BONUS: Video of Bart Knols vividly describing some of the malaria mosquito / stinky feet research, at TEDx Maastricht: