Transmission in changing word

Question 1

Which What can a 1 degree increase in temperature mean for species reservoirs?

Answer 1

changes in temp can impact the distribution and abundance of pathogens, vectors and reservoirs;
a 1 degree increase in spring is predicted to lead to a >50% increase in prevalence gerbil populations (reservoir of plague)

Question 2

Which reservoir species are particularly sensitive to temperature changes?

Answer 2

ectothermic vectors transmitting ectothermic pathogens

Question 3

What does warming of the climate mean for transmission of cholera?

Answer 3

warming in general has been linked to increased transmission of cholera
- cholera follows seasonal warming of sea surface temperature which enhances plankton blooms. Copepods which feed on plankton can act as reservoirs of cholera
- internal variability of cholera is strongly correlated to sea surface temperatures

Question 4

How does increased temperature affect malaria spread?

Answer 4

-temperatures affect malaria parasite development in complex ways
- increased temperatures increase rate at which infectious appear
- at warmer temps the development happens faster
- high temps don’t give you that high prevalences → proportion of the mosquitos that end up being infectious is actually lower
-there is an intermediate temperature that maximizes the speed at which they get through and the prevalence of the infectious ones

Question 5

Give some examples of effects of CO2 levels on disease transmission

Answer 5

• CO2 changes
  
  • direct measures on pathogens
  • fungus that causes bitter rot takes longer to germinate
  • reduced penetration in barley powdery mildew
  • increased fecundity of several plant pathogens

Question 6

How can extreme weather conditions affect the spread of water borne diseases?

Answer 6

Water-borne disease increase with these extreme events. Runoff can exceed the capacity of sewer system and many systems are designed to discharge the excess wastewater directly into surface water bodies. Water-borne disease outbreaks are seasonal and distinctly clustered around key watersheds Hrudey et al. 2003. A fatal waterborne disease epidemic in Walkerton, Ontario comparison with other waterborne outbreaks in the developed world. Water Sci. Technol 47(3):7-14. Mac Kenzie et al. 1994. A massive outbreak in Milwaukee of Cryptosporidium infection transmitted through the public water supply. N Engl J Med 1994: 331(3):161-197 For Vector-borne diseases increase rain may increase larval habitats and effect vector abundances Wet weather is associated with increases in rodent populations and subsequent disease transmission True for Hanta virus and leptospirosis Also true for the plague! Stenseth NC et al. Plague dynamics are driven by climate variation. PNAS 2006: 103(35): 13110-5.

Question 7

What will heavy precipitation events cause?

Answer 7

• for vector borne diseases increase rain may increase larval habitats and affect vector abundances
• wet weather is associated with increases in rodent populations and subsequent disease transmission

Question 8

How does change of land use affect the disease transmission? give an example

Answer 8

• increasing VBD by modifying the physical enrinoment
• In Russia there are 80 million ha of unused agricultural lands which are overgrown by forests, and it is impractical to convert most of them back. However these lands are potentially suitable for growing forests, which will help save natural forests in Russia, create more workplaces, etc. The collapse of the Soviet Union triggered the most drastic episode of land use change in the 20thcentury, most importantly the widespread abandonment of agricultural land [Henebry,2009]. Available agricultural statistics on sown areas suggest that approximately 50 million ha (Mha) of cropland were abandoned after 1990 in Russia, Ukraine, and Belarus [BELSTAT,2004;ROSSTAT,2010;UKRSTAT,2009]. This is another example of human modification of physical aspects of the ecosystem that can increase transmission, but increasing vector abundance.

Question 9

How can human interactions with nature affect the speed of disease?

Answer 9

• human encroachment of wildlife habitats has broadened the interface betweeen wildlife and§ humans resulting in an increased opportunity for emergence
• we can also change the interactions in nature that would otherwise not occur if it wasn’t for human encouragament (throwing out garbage in the forest); causing fights and different interactions which aids transmission

Question 10

How can damn formation affect disease spread an give an example of a solution

Answer 10

Can also impact other species of the community that not involved in transmission at all. n northern Senegal, the Diama dam, in the Saint-Louis region, marks the border with Mauritania. It is a work of the Organization for the Development of the Senegal River (OMVS), which has four member states: Senegal, Mauritania, Mali and Guinea. In service since 1986, this “anti-salt” dam has made it possible to develop agriculture in the River Valley. And 35 years later, it is a successful example of cross-border water management. Downstream, salt water from the Atlantic. Upstream, fresh water. With its seven gates, the mobile dam “blocks” the upwelling of saline water inland. ”There were periods of drought in the 1970s and 1980s when sea salt rose up to 200-300 kilometers upstream. And so it was impossible to make crops with salt water. And during this period there was a strong migration to Europe from this whole valley»,

Even more important are the results for our proxy of infection intensity (number of eggs in the urine (Schistosomaiosis);Fig. 3andTable 1), which is the best predictor of human disease (27). That is, despite having an initially higher egg burden before adding prawns, villagers had significantly lower egg burdens after we stocked prawns compared with controls at all follow-up time points (BACI interaction term,P< 0.0001;Fig. 3).

Question 11

how can change in vegetation structure change affectt the climate?

Answer 11

So processes that alter canopy cover can have profound effects on local climatic conditions. In a tropical forest system, changes in canopy cover due to selective logging, where large valuable timber trees are removed, can increase mean temperatures by 3C, which is on a par with some business-as-usual estimates for temperature rise under climate change. transmission is determined in large part by temperature, and that temperature can vary considerably across fine-spatial scales , a mechanistic understanding of how land-use change affects mosquito-borne disease transmission necessitates first quantifying the microclimatic conditions at a scale relevant to mosquitoes.; When you change the landscape you change how the environment can regulate the temperature

Logged forest canopy buffers the warmest part of the day. With bigger daily temperature ranges. Spending this time at the higher temperatures is enough to lead to changes in mosquito traits. Faster-hotter