Lecture 7. Emerging and Re-emerging Bacterial Diseases Flashcards
What is an emerging disease?
One that has appeared in a population for the first time, or that may have existed previously but is rapidly increasing in incidence or geographic range
What is a re-emerging disease?
A disease whose incidence has increased in a defined time period and location
What is the biggest concern regarding TB?
Drug-resistant forms of TB are on the rise
How many deaths from antimicrobial resistance are caused by drug-resistant TB?
1 in 3
What are factors attributed to re-emergence of infectious disease?
Human activity (behaviour, population movement, habitat encroachment, land use, etc.)
Climate and weather
Co-infection
Microbial adaptation and change
What is not a re-emerging disease?
An outbreak or a seasonal variation
What does transmission mean?
The mechanism in which a disease is spread i.e. faeco-oral, vector borne, etc.
What does incubation period mean?
The time between infection and symptom onset
What does carrier mean?
A person or animal without apparent disease who harbours a specific infectious agent and is capable of transmitting it to others
What does infectivity mean?
The proportion of persons exposed to a causative agent who become infected by an infectious disease
What does reservoir mean?
The habitat in which an infectious agent normally lives, grows and multiplies; can include human reservoirs, animals reservoirs, and environmental reservoirs
What does zoonoses mean?
An infectious disease that is transmissible under from animals to humans
What does endemic mean?
A disease which is constantly present in a population or geographical area
What does epidemic mean?
The occurrence of more cases of disease than expected in a given area or population over a particular period of time
What does pandemic mean?
Worldwide epidemic, effecting a large, widespread population simultaneously
What causes Lyme disease?
Borrelia burgdorferi
What transmits Lyme disease?
Zoonotic reservoir, vector borne transmission - bite of infected black legged tick
Who is most at risk of Lyme disease?
White; male; age 5-14 or 50-70
When did Lyme disease first emerge?
1960s and continuing to expand
When is Lyme disease most common?
May-August
What proteins do B. burgdorferi express?
Outer Surface protein A (OspA) - used for attachment to tick mid-gut
OspC
Does Lyme disease have a vaccine?
No
How can Lyme disease be prevented?
Reduce exposure to tick bites (personal protection, deer and land management, acaricides, education)
How can Lyme disease be treated?
Can be treated with doxycycline if caught early
What is the causative agent of cholera?
Vibrio cholerae 01 EI Tor
How is cholera transmitted?
Contaminated water (and food)
What does cholera cause?
Sudden and dramatic ‘rice water’ diarrhoea, due to the effect of the toxin
How does cholera cause death?
Death can occur due to excretion of 0.5 to 1l/h of diarrhoea, leading rapidly to tachycardia, hypotension, and vascular collapse due to dehydration
How many global pandemics have been caused by cholera?
6
How many cases of cholera are there annually worldwide?
1.3-4 million (only 140,000 reported)
What is cholera a key indicator of?
Lack of socio-eco development and sanitation
What is cholera re-emergence linked to?
Increasing size of vulnerable populations living in unsanitary conditions (displaced persons and infrastructure breakdown)
What is poor hygiene not cause by?
Class
How can cholera be prevented?
With safe water and sanitation
How can cholera be treated?
Cholera vaccine (Vaxchora, Dukoral, Shancho)
Rehydration therapy (Oral or intravenous; salts and mineral replacement )
Antibiotic treatment
Zinc treatment
Surveillance and rapid responses to outbreaks needed
What caused the cholera epidemic in Haiti in 2010?
Nepalese government forces arrival in Haiti after the earthquake (Nepal had an outbreak just before the earthquake)
How is Shigella spp. transmitted?
Food, water, reduced hygiene
What are Shigella spp. the etiological agents of?
Acute invasive intestinal infections clinically manifested by watery or bloody diarrhoea
How many people are affected by shigollosis every year?
At least 80 million, predominantly children
What 4 Shigella species can cause shigellosis?
S. dysenteriae
S. flexneri
S. boydii
S. sonnei
What are all Shigella species?
Multidrug resistant
What is a multidrug resistance?
Resistance to >3 classes of antimicrobial agents
