Background
The author writes that "early reviews about climate change exaggerated claims that infectious diseases will increase in the future," as he discusses in greater depth in another paper (Lafferty, 2009a), and as is also described by Randolph (2009).

What was done
In introducing a series of papers dedicated to this subject that were published in Ecology, Lafferty lists a number of ways in which ecologists "can contribute substantially to the general theory of climate and infectious disease."

What was learned
The most important challenges listed by Lafferty are those dealing with: "[1] multiple hosts and parasite species (Dobson, 2009), [2] nonhuman hosts (Harvell et al., 2009), [3] accounting for the effects of immunity (Dobson, 2009; Harvell et al., 2009; Ostfeld, 2009; Pascual and Bouma, 2009), [4] quality and details of [4a] climatic data and [4b] appropriate measures of disease response (Ostfeld, 2009; Pascual and Bouma, 2009; Randolph, 2009), [5] complex analyses to account for multiple, interdependent covariates (Dobson, 2009; Ostfeld, 2009; Pascual and Bouma, 2009, Randolph, 2009), [6] host movement in response to climate change (Harvell et al., 2009), and [7] geographic tools to account for distinctions between fundamental and realized niches (Ostfeld, 2009; Randolph, 2009)."

What it means
In light of the many and varied challenges that confront the scientific community in this emerging field of study, it is clear there is a lot of unfinished business that needs to be conducted in researching the several potential relationships that may (or may not) exist between climatic change and the spread of infectious diseases. The health catastrophes that are routinely predicted to occur by the world's climate alarmists in response to future global warming are definitely not yet ready for prime-time consideration.

References
Dobson, A.P. 2009. Climate variability, global change, immunity, and the dynamics of infectious diseases. Ecology 90: 920-927.

Harvell, C.D., Altizer, S., Cattadori, I.M., Harrington, L. and Weil, E. 2009. Climate change and wildlife diseases: When does the host matter the most? Ecology 90: 912-920.

Lafferty, K.D. 2009a. The ecology of climate change and infectious diseases. Ecology 90: 888-900.

Ostfeld, R.S. 2009. Climate change and the distribution and intensity of infectious diseases. Ecology 90: 903-905.

Pascual, M. and Bouma, M.J. 2009. Do rising temperatures matter? Ecology 90: 906-931.

Randolph, S.E. 2009. Perspectives on climate change impacts on infectious diseases. Ecology 90: 927-931.