29
© The Author(s) 2019
T. S. Rosenstock et al. (eds.), The Climate-Smart Agriculture Papers,
https://doi.org/10.1007/978-3-319-92798-5_3
Chapter 3
Climate Change and Infectious Livestock
Diseases: The Case of Rift Valley Fever
and Tick-Borne Diseases
Bernard Bett, Johanna Lindahl, and Grace Delia
3.1 Background
The global-average surface temperature has risen steadily since the nineteenth
century due to an increase in the concentration of heat-trapping gases such as carbon dioxide and methane in the atmosphere. These changes have had important
consequences on rainfall patterns, the intensity of droughts, and the viability of
ecosystems (Martin et al. 2008) among other changes. Taken together, these changes
have substantial effects on the transmission patterns of infectious diseases.
A few studies have been done to identify processes through which climate change
influences infectious disease occurrence. While more work needs to be done to fully
characterise these processes, the existing knowledge suggests two broad categories
of impact, often classified as ‘direct’ and ‘indirect’. Direct impacts are realised
when a rise in temperature, precipitation intensity, flooding, humidity, etc. increase
pathogens’ or vectors’ metabolic processes, reproductive rates, and (or) population
densities, resulting in enhanced vector–pathogen–host contact and, therefore, the
risk of disease (Bett et al. 2017). These changes operate within defined biological
limits. This is because an increase in temperature or flooding beyond a given threshold leads to the desiccation of these arthropods or the flushing of vector breeding
sites, and hence a decline in disease transmission risk. Direct effects are often associated with diseases caused by pathogens that spend part of their life cycles outside
B. Bett (*) · G. Delia
International Livestock Research Institute, Nairobi, Kenya
e-mail: b.bett@cgiar.org; d.grace@cgiar.org
J. Lindahl
International Livestock Research Institute, Nairobi, Kenya
Uppsala University, Uppsala, Sweden
Swedish University of Agricultural Sciences, Uppsala, Sweden
e-mail: J.Lindahl@cgiar.org
© The Author(s) 2019
T. S. Rosenstock et al. (eds.), The Climate-Smart Agriculture Papers,
https://doi.org/10.1007/978-3-319-92798-5_3
Chapter 3
Climate Change and Infectious Livestock
Diseases: The Case of Rift Valley Fever
and Tick-Borne Diseases
Bernard Bett, Johanna Lindahl, and Grace Delia
3.1 Background
The global-average surface temperature has risen steadily since the nineteenth
century due to an increase in the concentration of heat-trapping gases such as carbon dioxide and methane in the atmosphere. These changes have had important
consequences on rainfall patterns, the intensity of droughts, and the viability of
ecosystems (Martin et al. 2008) among other changes. Taken together, these changes
have substantial effects on the transmission patterns of infectious diseases.
A few studies have been done to identify processes through which climate change
influences infectious disease occurrence. While more work needs to be done to fully
characterise these processes, the existing knowledge suggests two broad categories
of impact, often classified as ‘direct’ and ‘indirect’. Direct impacts are realised
when a rise in temperature, precipitation intensity, flooding, humidity, etc. increase
pathogens’ or vectors’ metabolic processes, reproductive rates, and (or) population
densities, resulting in enhanced vector–pathogen–host contact and, therefore, the
risk of disease (Bett et al. 2017). These changes operate within defined biological
limits. This is because an increase in temperature or flooding beyond a given threshold leads to the desiccation of these arthropods or the flushing of vector breeding
sites, and hence a decline in disease transmission risk. Direct effects are often associated with diseases caused by pathogens that spend part of their life cycles outside
B. Bett (*) · G. Delia
International Livestock Research Institute, Nairobi, Kenya
e-mail: b.bett@cgiar.org; d.grace@cgiar.org
J. Lindahl
International Livestock Research Institute, Nairobi, Kenya
Uppsala University, Uppsala, Sweden
Swedish University of Agricultural Sciences, Uppsala, Sweden
e-mail: J.Lindahl@cgiar.org