Emerging infections Flashcards
What is an emerging infection?
Not occurred in human before
Occurred previously but only effected a small amount of peeps
Occurred through history but only recognized as a distinct disease due to an infectious agent
Where do most emerging infections come from?
Animals - zoonosis (75%)
What has contributed to emergence?
Mass food production systems (HUS - E. coli) Evolution of a strain (cholera) Pig-duck stuff (pandemic flu) Refusal of vax (pertussis) Break in health measures (rabies) Antibiotic resistance (TB)
Severe Acute Respiratory Syndrome (SARS) Coronavirus (CoV) characteristics
Enveloped (+) ssRNA virus
Readily transmissible and serve in the 21st century
Describe the emergence of SARS.
Chinese people on 2002 left in 2003
Spread via international travel
Fatal in 15% unless over 50 yrs (50%)
What is the natural reservoir for SARS?
Bats
Intermed host = Palm civet
What is the pathogenesis of Middle East Respiratory Syndrome (MERS)?
Beta-coronavirus
How is MERS transmitted?
Person-to-person
How is MERs prevented?
Surveillance for severe acute respiratory infections (SARI)
Diagnostic testing
What was the emergence of A/H1N1 swine flu?
Mixing vessel hypothesis
2009
Triple reassortment in swine
How was mostly effected by A/H1N1?
Young people
How is A/H1N1 prevented?
Vaccine
What are the subtypes of A/H5N1 avian influenza (AI)?
H5 and H7
What are the factors contributing to A/H5N1?
Globalization and international trade
Marketing and farming practices
Wild birds
HPAI (highly pathogenic avian influenza)
How is A/H5N1 transmitted?
Direct contact with gross birds and poop
Farm movement of birds
What are the clinical presentations of A/H5N1?
Aggressive clinical course with deterioration and high fatality
Incubation 2 -8 days
Early symptoms: LRT illness, respiratory distress, sometimes bloody sputum
How is A/H5N1 prevented?
Surveillance measures
Biosecurity
When did cholera re-emerge?
2010
What is the pathogenesis of cholera?
Toxigenic O1 and O139 bacteria
Free-living organism
Found in fresh and brackish water
What are the clinical presentation of cholera?
Mild cholera: asymptomatic or causes a mild gastroenteritis
Severe cholera: Acute, profuse watery diarrhea “rice water”, vomit
Hypovolemic shock and death
Tachycardia, loss of skin turgor, dry mucous, hypotension
Muscle cramps, electrolyte imbalances
How is cholera prevented?
Improved sanitation
Education of the people
Currently no vaccine
When did cholera emerge in the US?
Transportation of bird, mosquitoes
How is cholera transmitted?
Bite of mosquito Culex pipiens (east US) Culex tarsalis (midwest + west) Culex quinquefasciatus (southeast)
What is the clinical presentation of pertussis?
Effects infants and young children
7 - 10 day incubation
Mild fever, runny nose, paroxysmal cough with whooping, apnoea
Pneumonia
