Wildlife 1

Question 1

Why should pathogens in wildlife concern you?

Answer 1

• transmission to humans + impact?
• transmission to domestic animals
• cost of control
• conservation
• legal obligation
• unpredictability of emergence
• ability to move long distances (air travel)

Question 2

List examples of wildlife zoonoses that originated in wildlife. What animal is thought to be the original source?

Answer 2

• SARS (bats)
• MERS (camels, bats)
• Influenza (birds)
• Rabies (bats, terrestrial carnivores)
• Ebola (bats, others)
• HIV (primates)
• WNV (birds)
• Nipah virus (bats)

Question 3

What is the most common non-foodborne animal-associated infections in UK humans?

Answer 3

Lyme dz (b.burgdorferi) 1040 cases/year
Following 2 = pasteurellosis, toxoplasmosis, leptospirosis

Question 4

Why is lyme disease increasing?

Answer 4

• increasing incidence and geographic spread
• cause for increase in USA was thought d/t more deer but actually small mammal predators have reduced –> increased small mammal hosts (rats, mice) which have spread the disease much more than the deer.

Question 5

Differentiate spillover host and maintenance host and reservoir host

Answer 5

• SPILLOVER HOST: infection is sporadic or can only persist if external sources of infection are present. can still be infectious to others or may be a dead end host
• MAINTENANCE HOST: infection can persist via horizontal transmission in the absence of any other source of infection. may or may not be a reservoir host.
• RESERVOIR: one or more epidemiologically-connect populations in which the pathogen can be permanently maintained and from which infection is transmitted tot eh defined target population: may be more than one species.

Question 6

Define spillover

Answer 6

• direct wildlife-human transmission is rare
• usually an intermediate (spillover) host involved
• spillover hosts: often domestic animals (especially livestock), develop severe severe dz themselves, are capable of shedding virus in large quantities (hence sometimes called amplifier hosts), pass infection to people.
• in humans will fizzle out or become a pandemic

Question 7

Outline hendra virus spillover

Answer 7

• from fruit bats

- became pandemic (but was outbreak, potential to have spread much more once in horses)

Question 8

Outline nipah virus

Answer 8

• bat reservoir
• 1st ID in 1998 in malaysian peninsula
• geography: asia
• transmission: urine/saliva suspected human-human
• Illness: encephalitis, fever, vomit, coma, respiratory arrest
• Causes of outbreak: feeding pigs fruit contaminated with bat saliva, mango plantations next to larger pig farms, hunting, deforestation
• control: pig cull

Question 9

Summaries

Answer 9

• 2/3 human dz are zoonotic
• vast majority (75%) emerging infectious dz arise in wildlife
• many examples
• spillover and maintenance host = crucial distinction