Lecture 14: Emerging Virus

Question 1

What are 4 ways a disease can be ‘emerging’

Answer 1

• Completely new
• New in a certain area
• In a new species
• New/unexpected incidence or pathogenicity in a known area/species

Question 2

What are the main drivers of pathogen emergence

Answer 2

• Increasing human population density
• Increased travel (humans and animal)
• Trade
• Poor biosecurity
• Poor animal management
• Increased antimicrobial uses
• Poverty
• Changing dietary habit (high meat diets)
• Climate change

Question 3

How did PRRSV emerge

Answer 3

• Porcine reproductive and respiratory syndrome virus
  o Normally not a strong virus but we have manufactured environments where the virus thrives
   Keep piglets at high density, artificial insemination (spread semen), lots of travel of pigs
  o Emerged in the 1980s – similar number of pigs but fewer farms (higher farm density)

Question 4

What drove/drives West Nile virus emergence

Answer 4

• West nile virus: temperature dependent (higher the temperature = more viral particles/infections)
  o New to NA in 1998 (from Israel to NY City)

Question 5

What are some additional emerging viruses

Answer 5

• Cowpox in reindeer
• Orf. In muskox
• H5N1 in cows and/or pigs
• Bovine leukemia virus: very slowly emerging virus

Question 6

Explain the relationship between blue tongue virus and Schmallenberg virus

Answer 6

• Blue tongue virus and SBV
  o Drivers: travel, trade, and climate change
  o From S Africa and appeared in Netherlands – initially transmitted BTV type 8 and now there is many more subtypes that have emerged
  o Transmit via midges
  o Vaccines have not been effective (because modified live)

o Schmallenberg virus: bunyavirus (simbu group virus – a group of viruses that have many human infecting viruses) – not zoonotic
 Malformed offspring: arthrogryposis, brachygnathia inferior, torticollis (twisted neck), scoliosis, ankylosis (stiff joints)
 Looks like blue tongue in sheep
o Very difficult to detect and differentiate BV and SBV
 Short time for virus production in animal
 Very short fever

Question 7

What is hendra virus

Answer 7

• Hendra virus: fruit bats in Australia – affect horses and humans (high mortality in humans)
  o Very one health issue – require many stakeholders to control

Question 8

What are the drivers of porcine epidemc virus

Answer 8

• Porcine epidemic diarrhea virus
  o Drivers: poor biosecurity/poor animal health management/ trade/changing dietary habits
  o Dried blood from slaughtered pigs fed back to alive pigs – an article concluded that it didn’t have a role in transmission but difficult to conclude that based on one study
  o Moving diseased pigs = spread disease
  o Politics and money influence the narrative of what is ‘true’ or not

Question 9

What are some sources of information for emerging diseases

Answer 9

• Canadian animal health surveillance system – information on all animals
• World animal health information system (part of the OIE) – global health info
• GLEWS
• ProMED
• Healthmap.org