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)
modern human infectious diseases are thought to have originated in ____ during the ____ period
in domestic animals during the neolithic period
where is the epicentre of the measles outbreak in Canada
Quebec
______ are microorganisms that cause infectious disease
pathogens
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 host immune response
4) replicate, using host resources
5) exit and spread to a new host
three types of bacteria which cause human disease
obligate pathogens
facultative pathogens
opportunistic pathogens
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
viruses have a ____ genome made of _____ that can be single or double stranded. Their genome is packaged in a ____ coat, which can be further enclosed in a ______
a small genome made of RNA or DNA that is single or double stranded. Their genome is packaged in a protein coat which can be further enclosed in a lipid envelope
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
_____ (are the most common infectious agents in humans living in developing countries
Helminths (parasitic worms)
______ are crucial determinants of the distribution of helminth infections (parasitic worms)
climate and topography
common examples of arthropod vectors
ticks and mosquitoes
BSE and CJD prion
bovine spongioform encephelopathy
Creutzfeldt-Jakob disease
established infectious diseases
endemic diseases that have been around for a long time with a relatively stable and predicatable level of morbidity and mortality
ex - diarrheal pathogens, parasitic diseases
newly emerging infectious diseases
those that have been detected in a human host for the first time
ex nipah virus, SARS, aids
re-emerging infectious diseases subclassifications
diseases that appear in new regions (ex - west nile virus appearing in the americas)
known diseases becoming drug resistant (antimicrobial resistant pneumonia)
already known diseases that reappear after a period of control or elimination (anthrax in the states, dengue in florida)
sudden outbreak of an emerging infectious disease are NOT caused by _____ but rather….
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
five changes in ecological or biological systems leading to emerging zoonotic diseases
altered pattern of contact between wild and domestic animals (nipah virus)
altered patterns of contact between direct human and wild animal 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
why is a one health perspective on zoonotic / infectious diseases important
the emergence and re-emergence of infectious diseases can be linked to events and activities across the human-animal-ecosystem interface.
as populations grow and industrialization increases, human and animal populations migrate, biodiversity changes, trends in disease may also vary
four main drivers of emerging zoonotic diseases
shared ecologies
socioeconomic development and altered ecosystems
wildlife trade
urbanization, consumer behaviour, and market chains
pathogens and higher human densities are more commonly found in
the tropics
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
zoonotic hantavirus is primarily found in _____ hosts and causes ______ in humans. Transmission occurs through ____
found in rodent hosts and causes hemorrhagic fever with renal syndrome in humans. Transmission occurs through inhaling aerosols of virus-contaminated rodent excrement
T/F: e.coli is the most common facultative gram-negative bacillus in the human intestinal tract
true - it begins to colonize the gut within hours of birth and is part of normal bacterial flora
which type of E. Coli enteropath is responsible for acute kidney failure in children and release the Shiga toxin
enterohemorrhagic E. Coli (EHEC)
