Wildlife Zoonoses 1

Question 1

Why are fruit bats often problematic?

Answer 1

Co-evolved with a lot of diseases so asymptomatic carriers of zoonotic dz

Question 2

Where are HIV/AIDS originated from?

Answer 2

• SIV apes/monkey virus
• 100 years ago no HIV!!
• DR Congo
• 1980s cluster of cases (pneumonia, young men, traced to flight attendants travelling to congo)
• lepracy vax transfer on needle
• hunting monkeys and chimps, spillover events from wildlife

Question 3

Why pathogens in wildlife may cause issue

Answer 3

• zoonosis
• transmission domestic animals
• cost of control
• conservation
• legal obligations
• unpredictability of emergence
• ability to move long distances

Question 4

Which populations of animals have more risk of zoonosis?

Answer 4

• wildlife

- few few come from domestic animals

Question 5

egs. of zoonoses originating from wildlife

Answer 5

• SARS (bats?)
• MERS (camels, bats?)
• Influenza (Birds?)
• Rabies (bats, terrestrial carnivores)
• Ebola (Bats?)
• HIV (Primates)
• West nile virus (Birds)
• Nipah virus (bats)

Question 6

Most common non-foodborne animals associated infections in humans UK

Answer 6

• Lyme disease (B. Burgderfori)
• Pasteurellosis (P. Multocida)
• Toxoplasmosis
• Leptospirosis
• Psittacosis
• Hydatid dz
• Toxocara
• Hanta virus

Question 7

Most common tick-borne infectious disease in UK, Europe and N. America?

Answer 7

Lyme dz

- Borrelia burgdorferi

Question 8

How is incidence of Lyme dz changing? Why?

Answer 8

• Increasing incidence and geographic spread
• In USA was attributed to more deer
• Actually number of foxes and predators had been destroyed so small mammal population ^ -> ^ cases

Question 9

Define spillover host

Answer 9

> infectious sporadic or can only persist if external sources infection present

• can be infectious to others
• may be a dead end host
• eg. TB in cats

Question 10

Define maintenance hosts

Answer 10

• infection can persist via horizontal transmission in the absence of source of infection
• eg. cattle and badgers TB

Question 11

Define reservoir

Answer 11

• 1 or more epidemiologically connected populations in which the pathogen can be permanently maintained and from which infection is transmitted to the defined target population
• may be more than one species
• eg. cattle AND badgers TB

Question 12

What is an intermediate host?

Answer 12

= spillover host = amplifier host

• usually a domestic animals especially livestock
• develop severe disease themselves
• capable of shedding LARGE QUANTITIES of virus
• pass infection to people

Question 13

What may occur when a disease is transmitted via amplifier hosts to people?

Answer 13

may fizzle out

-may become pandemic

Question 14

Give egs. of zoonoses that have transmitted through domestic animals

Answer 14

• Hendra virus fruit bats -> horses -> human pandemic
• Avian influenza virus wild birds -> poultry -> human pandemic OR fizzle out
• Nipah virus fruit bats -> pigs -> humans pandemic