Lecture 19: Invasive Pathogens Flashcards
List examples of invasive pathogens
- Salamander plague
- Invasive american bullfrog transmitting lethal fungus to amphibian host sp (alpine newt)
- Crayfish plague – transmitted to native crayfish
- Invasive gray squirrel have a virus that kills red squirrels
- White nose syndrome and bats
- Deformed wing virus in bees via varra mites
DO human migrations promote invasion?
yep
L> i.e. colonialism sucks
C. gattii?
tropical fungal pathogen
- casuses fatal infections of the lungs and CNS
- native range = Aus and Indonesia
- discovered in Canada
- c colonizes trees and soils, spores are airborne
- infects mammals and birds
- higher infections rtes in canada vs native range
Zika virus?
- native to Africa
- antibodies in locals
asian tiger mosquito is transmitting it - brain deformities and head deformities
Trend of global human infectious disease outbreaks?
- on the rise
Explain the epidemiological triad?
- vector transmits disease to host
- environment mediates this transfer, may or may not be hospitable to the vector and may not provide the right host , may not make the host susceptible enough
- maybe not a good enough environment for the agent itself
Ex: Peacock fish (ate up mesopredators that kept malaria mosquitos in check)
West nile?
- birds are the primary reservoir for the virus
- also invests horses and humans
- probably brought to the americas via illegal exotic bird trade
Asian tiger mosquito
- larvae brought to NA via tires from Japan
- vector of yellow fever, dengue fever, encephalitis etc
African mosquito
- vector for malaria
- introduced to Brazil by French ships coming from Africa
Zoonoses?
- diseases and infections of vertebrate animals that can be transmitted to humans
Zoonotic spillover in Africa?
- loss of forest cover and consumption of bushmeat drive contact between humans and wild hosts, leading to infections
Bushmeat?
- bushmeat : meat of wild animals captured in forested areas are brought to urban areas for sale – carrying viruses from wild otherwise not encountered by us
Forest fragmentation ?
increases edge of contact between human s and wild reservoirs of new pathogens
Discuss the influ virus
- outermsmbrane is covered with enzymes N and H
- these help the virus attach to, and break into and out of host cells
- different types of H and N and different viruses have different combinations of them
ex: H1N2
What do H and N antigens do to hosts?
- trigger immune response (antibodies)
- a persons immunity to these reduces prob of infection and severity of the disease
- immunity to one HN combination confers little to no protection against a diff combo
SOOOOO
mutations in viruses can create strains that infect large numbers
List two ways viruses can evolve
- Antigenic drift
2. Antigenic shift
Antigenic drift?
- genetic reassortment
- the whole HN combo changes
- large pieces of genome are exchanged between different viruses attacking THE SAME CELL
- produces novel flu strains distinct from all previous strains -> potentially pandemic
*pigs = mixing vessel for Influenza (bird virus and human viruses can mix and undergo drift) then infect a human
L> further mixing can occur when people are infected with a human virus and a bird virus
Why do many strains of influenza type A originate from China ?
- SE Asia
- due to intense agricultural activity among a dense human population
Issue with prairie dogs?
- monkeypox virus
- related to small pox but not as deadly
- endemic to Africa
- first discovered in monkeys
- first case in NA with people in 2003
***prairie dogs could be sitting in a warehouse with many animals, stressful situation, biologically damaged species may spread disease WHICH can then spread to us
SARS?
severe acute respiratory syndrome
- caused by coronavirus similar to cold virus
- jumped from the civet cat which was kept as pets, to humans
** bats are natural reservoirs of SARS like coronaviruses – probs passed them to civet cat
Paramoeba invadens?
- pathogenic amoeba caused mass mortalities of sea urchins
- non indigenous and periodically introduced by movements of warm water
- outbreaks occur in warm years
Issues with aquaculture?
- crowded = easy transmission
- introduced stock = worldwide dispersal of pathogens
- escapees transmit to wild populations
- excess nutrients promotes microbial growth
- overuse of antibiotics stimulates selection for supersets
Infectious Salmon Anaemia (ISA) virus?
- similar to flue
- can mutate and evolve
- causes hemorrhages in kidney and spleen and death
- no cure for infected fish
- fish seen in Norwegian fish farms
- now spread to NB Canada
Trout ulcer disease?
- bacterial infection of salmon and trout
- ruptures blood vessels
- kills
- introduced to GL before 1900 possible with brown trout stock from Germany
Emerging threat: Pfiesteria piscicida
- toxic dinoflagellate
- lesions in fish
- can hurt mammals
- native to mid atlantic coast
- recently in Norway
Oysters?
-global trade of larvae and adults worldwide
- carry many pathogens
-
Paralytic Shellfish Poisoning is rising??
- more outbreaks being identified by increased awareness and detection efforts
- Coastal waters are increasingly used for aquaculture greater nutrient loading and transfer of infected shellfish
- Coastal eutrophication is increasing the frequency of toxic algal blooms
- Increased transfers of dinoflagellates by ships
**Forms cysts on shellfish by the toxic dinoflagellate
