Discussion notes 1-5 Flashcards
Climate change
What are the common routes of infection for soil transmitted zoonotics? What factors effect these transmission routes?
- routes of infection: ingestion and aerosolization of dust particles
- air temperature and wind speed effect soil movement and aersolization
Climate change
How does climate change affect ascaris and trichuris?
- ascaris: can have a positive or negative effect on egg survival, depending upon the climate
- trichuris: climate change can help drive disease spread into novel populations
climate change
What preventative measures do we need to take concerning soil transmitted pathogens?
Largely transmitted via animal feces, resulting in a need to monitor livestock/wildlife populations for
disease/ environmental conditions
climate change
What are water transmitted zoonotics often a result from?
fecal contamination of water supply
climate change
how does climate change affect water borne zoonotics?
- An increase in rainfall after droughts results in flooding, which can lead to higher levels of exposure to various pathogens.
- Climate change shifts spatial boundaries of various diseases, including toxoplasmosis and echinococcus.
- Increased temperatures can result in faster development of pathogen larvae, such as increased speed of schistosome development inside snail vectors.
climate change
what preventative measures can be taken to reduce the risk of water borne pathogens?
Water sanitization, but water sanitation needs to take into account survivability of various pathogens. Ex. Cryptosporidium
and Giardia can survive some modern water treatment plants.
climate change
How can food borne zoonotics be tranmitted? Name a couple of food borne pathogens
- Can be acquired by handling/ encountering animals/livestock during food processing.
- e. coli and salmonella
climate change
How does climate change affect food borne zoonotics?
- Risk of antimicrobial resistance emerging and being exacerbated by climate change
- Different food borne pathogens may survive better during colder temperatures. Changes in weather
patterns will allow for pathogens to occupy new ecological niches. - Increased temperatures may affect human social eating behaviours and put them into contact with more at risk food.
climate change
How can we prevent spread of food borne pathogens?
- Can be prevented using basic sanitation, education of populations, surveillance of food products, educating farmers.
- Individual control techniques are valuable, but one must also consider systemic disease monitoring (ex. Health Canada monitoring for E. coli on various food items)
climate change
how has climate change affected lyme disease? how can we prevent the transmission?
- Ticks moving northward into newly suitable habitats. Birds arriving to migratory locations
sooner, increasing time for transmission. Ticks typically happy above 0 degrees. - Increased surveillance of tick infections remains important, as does educating the public on how to check themselves for ticks.
climate change
how has climate change affected WNV? How can we prevent transmission?
- Increase in mosquito populations to spread disease. Populations newly exposed to WNV. Less bird migration may increase time to spread disease.
- Proper irrigation and removal of still standing water important to reduce vector abundance.
climate change
how is plague, leptospirosis, hantavirus, and tuleramia affected by climate change?
- plague: Warming will result in more suitable habitat further north. Example of Squirrels in California,
likely increased plague prevalence northward and decrease southward. - leptospirosis: Increased flooding due to climate change has led to increases in cases
- hantavirus: Climate change can increase rodent
populations after large flooding events, but warming can reduce vole populations as voles can live under snow. - tularemia: Climate change has resulting in higher temperatures and record numbers of cases
comparative immunobiology
A Gram-negative bacterium is isolated from an infected mouse. After in vitro culture (i.e. grown in a lab) the purified bacterium is shown to cause the same disease in another mouse:
a) Which Koch’s postulate(s) is/are being satisfied by using this approach?
b) Could you still argue that the initial bacterial isolate is the causative agent, even if you were unable to grow it in the lab? Explain
c) Design a simple experiment to test your hypothesis that this is the causative agent
- Postulates 1-3 are being saitsifies: 1) isolted, 2) cultures, 3) infected a naive individual and it caused the same disease
- It is possible that the bacterium isolate cannot be cultivated in vitro due to specific requirements/conditions that cannot be achieved in the lab. OR In terms of Koch’s postulates, since the agent cannot be cultured, then no
- Record information about the isolated causative agent (gram stain, morphology, biochemical tests, etc.)
Negative control group: mice that are not infected with any infectious agent; positive control group: mice infected with a known infectious agent that causes a distinct disease; experimental group: mice infected with the suspected causative agent. If it cannot be cultured, have an infected individual in proximity to a naive individual. Observe disease course (if applicable) of the mice
During peak symptoms/disease course, re-isolate the causative agent, and determine if the isolated agent matches that described in i.
comparative immunobiology
Neutrophils are classical early immune defenders against infection. Unlike some other cell types (e.g. macrophages) they will not be at the site of infection when a pathogen first enters an animal host. Instead, they need to be called in.
a) You are a resident macrophage located at the site of pathogen attack. You just found out that you are being attacked by a fungal pathogen, and would like reinforcements from a neutrophil population that is stored distally (e.g. special neutrophil stores in the bone marrow). Will your plan be to activate a redundant or pleiotropic mechanism of immunity? Explain
Pleiotropy: need to mark the site of infection, need to increase permeability, attract the neutrophil, activate the neutrophil –> neutrophil recruitement requires cohesive action
comparative immunobiology
A novel viral pathogen that infects the skin has been circulating among frog populations. Then, this happened: Despite long evolutionary distances between frogs and mice, both display effective innate and adaptive arms of the immune system. Identify three reasons that could explain why this mouse did not get infected with this virus?
- Different host physiology - frogs are ectothermic, whereas mice are endothermic, meaning that they have different temperature requirements at which they function best at, so these different body temperatures can provide a barrier for viral replication.
- Physical distance - frogs and mice occupy different niches in the environment (frogs are primarily found proximal to standing water), so there is a smaller chance of interactions occurring between species, and therefore, the virus wouldn’t have much opportunity to spill over.
- Entry into cells - frogs and mice are quite different in terms of frogs being amphibians, while mice are mammals, so their cell morphology and physiologies will be different. This can include differences in the entry receptors required by viruses. While the virus can enter frog skin cells, mice skin cells may not have the same receptor or receptor shape to facilitate viral entry.
- Pathogens adapt to their host, and can evade a frog’s immune system – co-evolved with the frog, so it’s strongly adapted to a frog and cannot infect mice
- Mice have fur → physical barrier
- Mice grooming behaviors → saliva kills virus perhaps?
- Frog viruses probably survive better in aquatic environments → less UV, drier → desiccation
