1b- Physical Factors + Prevalence Flashcards
Prevalence
Number of cases of a disease in a population at a time
What Factors affect global patterns of disease and how
Climate = Temp, rainfall, humidity affect disease vectors
Relief = Influence of altitude on temp and rainfall patterns impact habitat of vectors
Water sources = stagnant water affects prevalence of water borne diseases
Rainfall =High levels near equator can lead to flooding and water borne disease = high temp + rainfall makes it humid
Low rainfall = lower air quality and respiratory disease
How does rainfall affect vectors of disease - Mosquitoes
Number of aquatic habitats depend on collection of stationary water, such as puddles in rainy season
Female Anopheles mosquitoes lay eggs in stagnant water sources
How does temperature affect disease vectors / Mosquitoes
Mosquitoes take more blood meals + lay more eggs when temp is high 18-40*C
Mosquito Larvae develop faster in high temperatures
How does humidity affect disease vectors
Mosquitoes have higher chance of survival + becomes more active when average humidity = 60%>
How do seasonal variations influence disease outbreaks
Rainy season/monsoons = Many vector diseases occur in tropics and can be seasonal = high temp + moisture levels
Winter months = shorter winter days + more time spent indoors = vitamin D is lower
Immune system is more susceptible
- eg: the Influenza/Flu virus most efficient at lower temps (5*C )+ humidity during winter
What is a vector
Living organisms that transmit infectious diseases
Short term changes climate change may have on disease
Increased frequency of tropical Storms and flooding = higher rates of Cholera , Malaria and Dengue
Long term impacts of climate change on diseases
Shifts in geographical patterns of diseases due to changing weather and climate patterns
Climate change affect on the West Nile virus
Increased Temperature + Rainfall + Humidity
Western Africa prevalence of WNV will increase = more spread of vector borne diseases
More mosquitoes to infect birds = Birds carry virus to new areas = mosquitoes get infected by birds in new area = infect ppl
Climate change affect on Lyme disease
Higher temperatures throughout USA and Canada = Ticks thrive in warm conditions
Disease may spread North to areas that ticks previously could not survive
Climate change affect on Sleeping sickness
Higher temperatures increasing growth rate of Tsetse Fly
Disease moves southwards from Sub-Saharan Africa to previously colder regions = infect 80 million more people
However disease may decrease in east Africa as too hot
Conditions for increased probability of spread of zoonotic diseases from animals to humans
Poor hygiene and sanitation = contaminated drinking water by animal Faeces and in general just easier to spread
Urbanisation provides habitats for contaminated animals - Foxes, skunks or racoons = control of these animals in urban areas is limited
Vaccination of pets is sparse = more likely to get infected and transmit disease
Emerging infectious disease
Infections that have have recently appeared within a population or have begun rapidly increasing
