Understanding the link between malaria risk and climate.

Center for Infectious Disease Dynamics, Department of Entomology, Chemical Ecology Laboratory, Pennsylvania State University, University Park, PA 16802, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 09/2009; 106(33):13844-9. DOI: 10.1073/pnas.0903423106
Source: PubMed

ABSTRACT The incubation period for malaria parasites within the mosquito is exquisitely temperature-sensitive, so that temperature is a major determinant of malaria risk. Epidemiological models are increasingly used to guide allocation of disease control resources and to assess the likely impact of climate change on global malaria burdens. Temperature-based malaria transmission is generally incorporated into these models using mean monthly temperatures, yet temperatures fluctuate throughout the diurnal cycle. Here we use a thermodynamic malaria development model to demonstrate that temperature fluctuation can substantially alter the incubation period of the parasite, and hence malaria transmission rates. We find that, in general, temperature fluctuation reduces the impact of increases in mean temperature. Diurnal temperature fluctuation around means >21 degrees C slows parasite development compared with constant temperatures, whereas fluctuation around <21 degrees C speeds development. Consequently, models which ignore diurnal variation overestimate malaria risk in warmer environments and underestimate risk in cooler environments. To illustrate the implications further, we explore the influence of diurnal temperature fluctuation on malaria transmission at a site in the Kenyan Highlands. Based on local meteorological data, we find that the annual epidemics of malaria at this site cannot be explained without invoking the influence of diurnal temperature fluctuation. Moreover, while temperature fluctuation reduces the relative influence of a subtle warming trend apparent over the last 20 years, it nonetheless makes the effects biologically more significant. Such effects of short-term temperature fluctuations have not previously been considered but are central to understanding current malaria transmission and the consequences of climate change.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Malaria epidemics remain a serious threat to human populations living in the highlands of East Africa where transmission is unstable and climate sensitive. An existing early malaria epidemic prediction model required further development, validations and automation before its wide use and application in the region. The model has a lead-time of two to four months between the detection of the epidemic signal and the evolution of the epidemic. The validated models would be of great use in the early detection and prevention of malaria epidemics.
    Malaria Journal 08/2014; 13(1):329. · 3.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Since its reappearance at the Military Demarcation Line in 1993, malaria has been occurring annually in Korea. Malaria is regarded as a third grade nationally notifiable disease susceptible to climate change. The objective of this study is to quantify the effect of climatic factors on the occurrence of malaria in Korea and construct a malaria occurrence model for predicting the future trend of malaria under the influence of climate change. Using data from 2001-2011, the effect of time lag between malaria occurrence and mean temperature, relative humidity and total precipitation was investigated using spectral analysis. Also, a principal component regression model was constructed, considering multicollinearity. Future climate data, generated from RCP 4.5 climate change scenario and CNCM3 climate model, was applied to the constructed regression model to simulate future malaria occurrence and analyze the trend of occurrence. Results show an increase in the occurrence of malaria and the shortening of annual time of occurrence in the future.
    International journal of environmental research and public health. 01/2014; 11(10):10587-10605.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Malaria a very serious health problem is caused by plasmodium parasite and transmitted by female Anopheles mosquito. Despite various efforts to control malaria, it remains the world's most pervasive infection. Insecticide treatment for vector control is a fundamental element of the existing strategy to control this deadly disease. However, malaria vector control strategies are beset with the limitation of development of resistance to insecticides. This warrants development of alternative malaria control approaches. Paratransgenesis involves the modification of genes of the symbionts of host to deliver anti-parasitic molecules in the malaria vector which can interfere with pathogen transmission. The selection of host-specific microbial species is very important in paratransgenesis. The non-resident bacteria are often unable to colonise into a new micro-environment (mosquito gut) so that indigenous gut bacteria are favored to be used a paratransgenic delivery vehicles. In search of candidate for this approach, microbial community of mosquito gut needs to be investigated. In the present study we found differences in number as well as in the type of genera of bacteria isolated from the same Anopheles species of two different breeding sites i.e. mosquitoes from different laboratories as well as from different field populations of the same geographical area.

Full-text (2 Sources)

Available from
May 20, 2014