Lecture 13: Wildlife Viruses

Question 1

What are the 3 main consequences of wildlife diseases (+examples)

Answer 1

Consequences
* Can impact energy stores required for life events (migration)
o The cost of immunity (regardless of pathogenicity) – reduces survival

• Bottle neck events result in inbreeding depression
  o Ex. high rate of sea lion carcinoma
  o FIP in cheetahs (very limited genetic diversity) – high rate of mortality
• Impact reintroduction
  o Bandicoot papillomatosis carcinomatosis virus type 1 – oncogenic virus (papilloma and polyoma virus combo) – high mortality/increase risk of predation
   Virus introduced to wild bandicoots via released
  o Attwater’s prairie chicken – reticulo-endotheliosis (retrovirus)
   Spread to wild birds via reintroduction efforts

Question 2

What are examples of 2 large DNA viruses in wildlife

Answer 2

• Have evolved in populations for a long time
  Herpes Viruses
• Fibropapilloma-associated turtle herpesvirus
  Papilloma virus
• Human and canine papillomatosis

Question 3

Explain rabies in canadian wildlife? How to control it

Answer 3

Rabies
* Widespread distribution – select areas are negative (due to active measures to eradicate)
* In Canada: Bats, Skunks, Arctic Fox,
* Historically rabies moved from northern Canada down to the southern parts
* Management: Live trapping, Oral wildlife vaccines (all attenuated live)
o Vaccinia: modified pox virus (can induce pustules in people via handling with bare skin)
o Vaccine effective in wild populations
 Rabies suppressed in wild foxes – resulted in an increase in fox population

Question 4

How do viruses impact wildebeests in the serengeti and how does that impact other populations in the ecosystem

Answer 4

Wildebeest in Serengeti
* Increase in forestation in Serengeti (after forest depletion in 1980)
* Mara triangle
* Rinderpest higher prevalence in population of wildebeest
o High antibody levels in wildebeest populations in 1960’s + significantly reduced wildebeest populations
o Low wildebeest population results in higher amounts of uneaten grass = increase fire risk (reducing trees)
* Vaccination of livestock (cattle) – reduced spillover into wildebeest population = increasing wildebeest population an reducing antibody levels in wild populations
* Also impact numbers of predators (lions)

Question 5

How have viruses been used in rabbit control

Answer 5

Rabbits in Spain
* Rabbit hemorrhagic disease virus: calicivirus, almost eradicated rabbits in Spain
o Impacted Iberian lynx’s (main diet is rabbits) – almost extinct
* Mitigation: building rabbit habitats (dens), make fire breaks
o Rabbit breeding programs
o Re-introducing lynxes – ensuring areas that lynxes can enter but other predators can’t (fenced)
Rabbits in Australia
* Myxomatosis virus used as a control measure to reduce rabbit populations
o Rabbitt eventually because resistant
* Introduced rabbit calicivirus – effective in depopulating

Question 6

How has HPAI moved through wildlife

Answer 6

HPAI (H5N1)
* Low pathogenic AI: in waterfowl/floating birds
o Can recombine and turn into HPAI (usually occur after introduction into a chicken or turkey barn)
* Non-floating birds don’t typically have low path AI
* H5N1 has 50% mortality in humans
* Subtype: Guangdong H5 clade 2.3.4.4b resulted in HPAI
o This sub-strain not common in humans
* Spill-over into dead end hosts as well as transmitting hosts
o Harbour seals
o Black bear
o Foxes

Question 7

How has sars CoV2 impacted wild populations

Answer 7

Sars CoV2
* White tailed deer in Michigan, Wisconsin, Pennsylvania
* High numbers of positive animals in 2021
o Almost 80% prevalence in Ohio in 2022
* There has been cases of deer to human transmission in Ontario
* Lots of different Sars CoV2 lineages