Emerging Infectious Diseases Flashcards
How many new human diseases have emerged over the past 20 years?
At least 30.
What 2 factors determine if a disease is emerging?
- Previously unknown disease that suddenly appears (emerges) in a population.
- Known disease that suddenly appears (emerges) in a new population.
What determines a re-emerging disease?
Known disease, previously on the decline, that is becoming more common and will likely continue to do so.
Where did the 2001 outbreak of Foot and Mouth disease occur?
During what time period?
When was the last outbreak in this area?
- UK
- February to October
- 1967
What was done to stop the Foot and Mouth disease outbreak?
Massive culling of animals.
What are the 5 stages of cross-species disease emergency?
- Pathogen exclusive to an animal reservoir.
- Animal reservoir transmits to humans/other animals, but no transmission among them.
- Animal reservoir transmits to humans/other animals with a few cycle of transmission among them.
- Animal reservoir transmits to humans/other animals with sustained transmission among them.
- Pathogen exclusive to humans/new animal reservoir.
T/F: Many pathogens have multiple host species.
True
What percentage of pathogens have only one known host?
37.3%
What are 3 examples of stage 2 diseases? What are their reservoirs and dead-end hosts?
- Rabies: Reservoirs-carnivores and chiroptera (bats); Dead-end hosts-cattle and horses
- WNV, EEEV, WEEV: Reservoirs-birds; Dead-end hosts- humans, horses and dogs
- Influenza H5N1: Reservoirs-waterfowl and poultry; Dead-end hosts-humans
When and where was the first outbreak of H5N1 avian influenza?
1997, Hong Kong
Where was the 2004 outbreak of avian influenza?
Southeast Asia
What are 2 examples of stage 3 pathogens, their reservoirs and how they are transmitted?
- Mycobacterium bovis: Reservoir-cattle, bison, elk; transmission-to people via respiratory route (poor human-to-human transmission).
- Nipah virus: Reservoir-fruit bats; transmission-human-to-human and pig-to-pig.
When and where did the Nipah virus emerge?
Sept 1998 - April 1999 in Malaysia
Rapid transmission of Nipha virus between pigs was seen by what route?
Respiratory
The Nipah virus outbreak had a human fatality rate of what percentage?
Many cases involved what?
Survivors often had what type of a sequelae?
- 40%
- Encephalitis
- Neurological sequelae
What are 3 examples of stage 4 pathogens, their reservoirs and transmission?
- SARS (Sever Acute Respiratory Syndrome): Reservoir-fruit bats; transmission-efficient in humans
- Schmallenberg virus: Reservoir-unknown; transmission-efficient in sheep, goats and cattle
- 2009 Influenza H1N1 (Swine influenza): Reservoir-swine; transmission-very efficient in humans
When was the first human case of swine influenza detected and where?
When and where were the first pig cases of swine influenza detected?
- April 2009 in Mexico
- Late April 2009 in Canada
When was the 2009 H1N1 outbreak officially declared pandemic by the WHO?
June 11, 2009
What are 5 examples of stage 5 pathogens and their sources of origin?
- HIV/AIDS: non-human primates
- Measles: cattle
- Smallpox: likely camels (camel pox)
- Dengue fever: Old world primates
- Yellow fever: African primates
What are 4 drivers to pathogen emergence?
- Land use changes
- Food and agricultural systems
- Environmental systems
- Human behavior
What are 4 determinants of emergence?
- Pathogen: type of agent and mutation/change
- Reservoir: Phylogenetic distance
- Transmission: Reservoir size, pathogen prevalence and contact frequency
- Host: Susceptibility
Of the over 1400 species of pathogens known to infect humans, how many are zoonotic?
61%
What percentage of emerging diseases of humans are zoonotic?
75%
Zoonotic pathogens are twice as likely to be associated with what?
Emerging diseases
