lecture 9 - zoonotic/onehealth/vector borne diseases Flashcards
three sectors of the one health approach
public health (healthy humans)
environmental (healthy ecosystems)
veterinary health (healthy animals)
where is the epicentre of the measles outbreak in Canada
Quebec
pathogens use this five step process to multiply and survive
1) colonize in the host
2) find a nutritionally compatible niche in the host body
3) avoid, subvert, or circumvent the host innate and adaptive immune response
4) replicate, using host resources
5) exit and spread to a new host
obligate pathogens
only replicate inside the cells of the human body
ex tuberculosis
facultative pathogens
replicate in an environmental reservoir such as water or soil and only cause disease if they happen to encounter a susceptible host
ex salmonella
opportunistic pathogens
normally benign but have a latent ability to cause disease in an injured or immunocompromised host
ex candida albicans
MCQ - viruses replicate by themselves
false - they cannot replicate by themselves, they use host machinery for their multiplication
why are fungi and protozoan parasitic infections harder to treat
because they are eukaryotes, it is more difficult to find drugs that will kill them without harming the host
fungal and parasitic infections have the tendency to switch among several different forms during their life cycle, where a drug that is effective in killing one form may not work on the other
antifungal and antiparasitic drugs are often less effective and more toxic when compared to antibiotics
what is the most common protozoal disease
malaria - caused by four species of plasmodium (a single cell parasite) transmitted to humans by the bite of a female mosquito
common protections from malaria
nets to protect form mosquitos
cleanliness of gardens/trees/backyards to prevent breeding grounds
mosquito repellants
established infectious diseases
endemic diseases that have been around for a long time with a relatively stable and predicatable level of morbidity and mortality
newly emerging infectious diseases
those that have been detected in a human host for the first time
ex nipah virus, SARS
re-emerging infectious diseases subclassifications
**
what may trigger a sudden outbreak of an emerging infectious disease
they are NOT caused by sudden mutations in a pathogen, but rather when an existing pathogen gains new access to a new host population
factors such as: climate change, changes in human activities like farming and reforestation, technological changes like air travel and organ transplantation, demographic changes like migration to cities, wild game, companion animals
drivers of emerging zoonotic diseases
altered pattern of contact between wild and domestic animals (nipah virus)
altered patterns of contact between direct human and wild contact (ebola)
changes in species abundance or diversity (hantavirus, lyme)
species diversity, including the diversity of insect vectors and pathogenic microorganisms
a correlation between the emergence of zoonotic pathogens and the diversity of mammalian wildlife species
vectors
living organisms that transmit pathogens between humans, or from animals to humans
ex - bloodsucking insects which ingest disease-producing microorganisms from an infected host and then transmit it to a new one
this class is not talking about clone DNA vectors
main pathogens of infectious disease
virus, parasite, bacteria
what is an infectious disease
disease caused by pathogens like viruses, parasites, fungi, bacteria which enter the host body, multiply, and then cause infection. these pathogens may be spread by vectors (such as insects, mice) or animals
risk factors for vector borne diseases with connection to One Health
increased human mobility
population growth
trade
climate change
