Krijn Paaijmans

111 Merkle Lab
University Park
PA 16802, USA

Tel. +1 814 865 1024
krijn@paaijmans.nl
http://www.paaijmans.com


Research interest

Relevant microclimate in mosquito and malaria biology

Mosquitoes are small, cold-blooded, short-lived insects whose development and behavior is strongly linked to prevailing conditions. That the dynamics and distribution of malaria is therefore affected by environmental factors such as temperature is not in question. But exactly how it will be affected is unclear because there is still relatively little known about basic malaria and mosquito biology in relation to natural temperatures in the field. The aim in my studies is to better inform the current debate by examining the relevant microclimate and its effect on mosquito and malaria biology. Some examples:

Water vs. air temperature

The relationship between mosquito development and temperature is one of the keys to understanding the current and future dynamics and distribution of vector-borne diseases such as malaria. Many process-based models use mean air temperature to estimate larval development times, and hence adult vector densities and/or malaria risk. However, water temperatures in typical mosquito breeding sites are in general higher than the temperature of the adjacent air, resulting in larval development rates, and hence population growth rates, that are much higher than predicted based on air temperature. Existing models will tend to underestimate mosquito population growth under current conditions, and may overestimate relative increases in population growth under future climate change.
See our paper in Malaria Journal [1]

The meaningless mean temperature

There are six essential parasite and mosquito life-history traits (i.e. all the entomological parameters) that combine to determine malaria risk. Many studies link malaria dynamics to coarse measures of environmental temperature, such as mean monthly temperatures. Yet mosquitoes experience temperatures that vary from hour to hour and do not live under ‘average monthly conditions’. We have shown that in addition to mean temperatures, daily fluctuations in temperature affect parasite infection, the rate of parasite development, and the essential elements of mosquito biology that combine to determine malaria transmission intensity. In general, we find that, compared with rates at equivalent constant mean temperatures, temperature fluctuation around low mean temperatures acts to speed up rate processes, whereas fluctuation around high mean temperatures acts to slow processes down.
See our papers in PNAS [2, 3]

These results highlight the need for better integration of biological and environmental information at the scale relevant to mosquito biology.

These studies were supported by a Netherlands Organisation for Scientific Research grant and a National Science Foundation EID program grant.


Degrees

Research experience

Publications

KP Paaijmans, S Blanford, AS Bell, JI Blanford, AF Read & MB Thomas. Influence of climate on malaria transmission depends on daily temperature variation.
PNAS (2010) 107: 15135–15139. [SI]

KP Paaijmans, SS Imbahale, MB Thomas & W Takken. Relevant microclimate for determining the development rate of malaria mosquitoes and possible implications of climate change.
Malaria Journal (2010) 9:196.

KP Paaijmans, AF Read & MB Thomas. Understanding the link between malaria risk and climate.
PNAS (2009) 106: 13844–13849. [SI]

KP Paaijmans, S Huijben, AK Githeko & W Takken. Competitive interactions between larvae of the malaria mosquitoes Anopheles arabiensis and Anopheles gambiae under semi-field conditions in western Kenya.
Acta Tropica (2009) 109: 124-30. [pdf]

KP Paaijmans, BG Heusinkveld & AFG Jacobs. A simplified model to predict diurnal water temperature dynamics in a shallow tropical water pool.
International Journal of Biometeorology (2008) 52: 797-803.

KP Paaijmans, W Takken, AK Githeko & AFG Jacobs. The effect of water turbidity on the near-surface temperature of larval habitats of the malaria mosquito Anopheles gambiae.
International Journal of Biometeorology (2008) 52: 747-753.

KP Paaijmans, AFG Jacobs, W Takken, BG Heusinkveld, AK Githeko, M Dicke & AAM Holtslag. Observations and model estimates of diurnal water temperature dynamics in mosquito breeding sites in western Kenya.
Hydrological Processes (2008) 22: 4789-4801. [pdf]

AFG Jacobs, BG Heusinkveld, A Kraai & KP Paaijmans. Diurnal temperature fluctuations in an artificial small shallow water body.
International Journal of Biometeorology (2008) 52: 271-280. [pdf]

KP Paaijmans, MO Wandago, AK Githeko & W Takken. Unexpected high losses of Anopheles gambiae larvae due to rainfall.
PLoS ONE (2007) 2(11): e1146.

S Huijben, W Schaftenaar, A Wijsman, K Paaijmans & W Takken (2007). Avian malaria in Europe: an emerging infectious disease? In: Emerging pests and vector-borne diseases in Europe. Takken W & Knols BGJ, editors. Wageningen Academic Publishers, Wageningen.

CJM Koenraadt, KP Paaijmans, P Schneider, AK Githeko & W Takken. Low larval vector survival explains unstable malaria in the western Kenya highlands.
Tropical Medicine and International Health (2006) 11: 1195-1205. [pdf]

E-J Scholte, K Ng’habi, J Kihonda, W Takken, K Paaijmans, S Abdulla, GF Killeen & BGJ Knols. An entomopathogenic fungus for control of adult african malaria mosquitoes.
Science (2005) 308: 1641-1642. [pdf]

CJM Koenraadt, KP Paaijmans, AK Githeko, BGJ Knols & W Takken. Egg hatching, larval movement and larval survival of the malaria vector Anopheles gambiae in desiccating habitats.
Malaria Journal (2003) 2:20.

= open access


Miscellaneous

Interests:
Building websites like this beauty ;)
Hiking and camping with Silvie, Lara & Boogie (our dog)
Running races (occasionally)
Drinking lots (no even more) of coffee
Always interested in funding...

Scientific motto:
Better to be rejected than to be retracted

Other:
If you have comments or questions about my work, send me an email!