Infectious Diseases Flashcards
What are some factors behind the emergence and re-emergence of infectious diseases? Use specific diseases to illustrate answer.
- Resistance to antibiotics, anti-malarials, pesticides
- Globalization (Travel, loss of herd immunity)
- Overpopulation (Disease transmission between humans and livestock, poor sanitation)
- Environmental Change (Climate, land use)
How might global climate change influence the prevalence and distribution of infectious diseases? Use specific diseases to illustrate your answer.
- Effects on disease vectors
- Effects on disease agents
- Effects on the local environment (flooding)
- Drought and water availability
- Effects on agriculture and nutrition
ex. Malaria and dengue fever increase around water
Evaluate how human impacts on local environments influence the prevalence and distribution of infectious diseases? Use specific disease to illustrate answer
- Disposal of waste and feces
- Travel to water sources enhances distribution
- Living in close proximaty with infected animals
ex. diarrhea from poor sanitation
Should indoor residual spraying with DDT be used to control malaria? What factors would you need to consider to make a good decision?
It’s debatable. Should consider how many mosquitoes per given home with and without DDT to see if it’s having an effect. Also should note how detrimental the disease is to infected humans vs. negative side effects of DDT.
Describe the global disease burden related to malaria
- 700,000 - 2.7 million deaths worldwide each year
- 41% of world’s pop. lives in areas where malaria is endemic
In what regions of the world is malaria endemic?
Africa
- 75% deaths from children in Africa
- Approx 1 million deaths per year in Africa
Describe the life cycle of the Plasmodium parasite, including both human and mosquito hosts
In mosquito –> enters human as Sporozoites –> enters human liver and splits into many Merozoites –> Merozoites leave liver and enter Red Blood Cells –> Eventially pop blood cells, releasing many merozoites into body (causing symptoms) –> male/female merozoites fertilize to become Gametocytes –> Gametocytes eaten by mosquito and fertilized in mosquito –> Repeat
How can the malaria transmission cycle be broken? Consider the location of the greatest abundance of Plasmodium organisms, the locationof the greatest number of mosquitoes, and the major food sources of mosquitos
Greatest Abundance of Organisms? = On the people/host
Where most of the mosquitoes reside? = Outside/by water
Upon what do most mosquitoes feed? = Cattle/wild animals
Describe the recent importance of new anti-malarial drugs in malaria therapies ( do not worry about memorizing the names of specific drugs).
- In conventional monotherapies, plasmodium parasites become resistant
- With new artemisinin drugs, no resistence and rapid therapy
Describe options for controlling mosquito bites in malaria prone areas.
- Pesticides (broad spraying of natural areas and areas around homes; indoor residual spraying ex. DDT)
- Bednets
Describe how the prevalence of malaria was significantly reduced Oaxaca State, Mexico
People who have had malaria the year or two before are given preventative medication during the malaria “high season.” Their houses are also sprayed with a pyrethroid-based insecticide that, unlike DDT, does not persist in the environment. Also, women are removing algea
Is indoor spraying of DDT safe for humans? Why or why not?
No, studies show that DDT increase risk of breast cancer among women
Briefly describe the current WHO alert status for pandemic flu.
Phase 1-3: Predominantly animal infections; few human infections
Describe the importance of the hemagglutinin and neuraminidase proteins in the biology of the influenza virus. Consider their location on the virus particle, their rates of mutation, and their roles in infecting host cells and stimulating an immune response.
These are the 2 proteins on the surface of the virus; responsible for binding the virus to cells with sialic acid on the membranes, such as cells in the upper respiratory tract or erythrocytes;
Describe the two major ways that the influenza vaccine can mutate. How did the virus mutate to form the current H1N1 strain? Which way is most likely to produce a human pandemic related to the H5N1 strain.
- Antigenic drift (losses parts to fit on host cell)
2. Antigenic shift (joins with another flue to form new strain)
