7 Emerging & Re-Emerging Diseases Flashcards
what are emerging infectious diseases?
infections that have recently appeared within a population or those whose incidence or geographic range is rapidly increasing or threatens to increase in the near future
what can cause emerging infectious diseases?
- previously undetected/unknown infectious agents
- known agents that have spread to new geographic locations or new populations
- previously known agents whose role in specific diseases has previously gone unrecognized
between 1940-2004, there were ____ emerging infectious disease (EID) origins reported globally
335
(mostly viral)
what are re-emerging infectious diseases?
diseases that were once thought of as being under control primarily due to the use of antibiotics, vaccinations, and insect control
name 8 examples of re-emerging infectious diseases
- tuberculosis
- cholera
- malaria
- whooping cough
- diphtheria
- measles
- mumps
- polio
name 4 examples of emergent diseases which appear when humans encroach upon new land, increasing contact with new pathogens
- lyme disease
- hanta virus (sin nombre)
- dengue fever
- nipah virus
what does nipah virus cause?
encephalitis or respiratory illness
how is nipah virus transmitted?
animal to human or human to human
treatment of nipah virus
no treatment or vaccine available for people or animals
what is the natural host of nipah virus?
fruit bats
name 3 examples of foodborne infectious diseases
- E. coli O157:H7
- “mad cow” disease
- Salmonella
in september 2016, 8 multistate outbreaks of human salmonella infections were linked to…
live poultry in backyard flocks
(total: 895)
what factors impact the globalization of disease?
modern air travel
global trade
name 4 examples of globalized diseases
- avian influenza
- tuberculosis
- cholera
- bubonic plague
what disease mutates rapidly and is more deadly than any other form of influenza, specifically 10x more deadly than the Spanish flu?
Avian influenza
mortality rate of avian influenza
- could be as high as 50%
- expected 0.1-2.5%
Zika virus
- outbreaks after Brazil olympics
- seen in states with ^college athletics -> ^travel
- conjunctivitis, fever, joint pain, rash
Dengue Hemorrhagic fever is also known as ____
breakbone fever
globalization of Dengue hemorrhagic fever is comparable to that of ____
Malaria
what is the case-fatality rate of dengue hemorrhagic fever? what population are fatal cases most common?
5%
mostly children
manifestation of Chikungunya virus
- symptoms begin 3-7 days after infectious mosquito bite
- fever, joint pain, headache, muscle pain, joint swelling, rash
- can be severe & disabling
- joint pain may persist for months
what is the etiologic agent of middle east respiratory syndrome (MERS)?
coronavirus
manifestation of MERS
- severe respiratory illness with symptoms of fever, cough, shortness of breath
- mortality rate: 30-40%
Severe Acute Respiratory Syndrome (SARS):
source
year
transmission
mortality rate
- China
- 1990
- droplet aerosol & fomites
- 10%
where is high viral load of SARS found in the body?
lower respiratory tract
West Nile Virus:
source
year
transmission
host
mortality rate
- Africa
- 1999
- mosquito
- birds
- 15%
West nile virus causes ____
encephalitis
name 4 examples of viral hemorrhagic fevers
ebola
marburg
lassa
yellow fevers
Viral hemorrhagic fevers:
source
transmission
mortality rates
- tropics
- arboviruses (insects) & unknown
- strain-specific: 5-90%
Viral hemorrhagic fevers can cause ____
circulatory shock
tuberculosis, influenza, and prion diseases are examples of ____
re-emerging diseases
epidemiology of tuberculosis
- ~2 billion people infected worldwide
- 8 million new infections per year
- 2 million deaths per year
- most cases from 1993-2009 in Mexico
what are the possible causes for 1increases in tuberculosis?
- HIV/AIDS epidemic (Africa)
- ^poverty, IV drug use, homelessness (US)
- ^immigration of infected individuals (US)
- ^elderly population (US)
- failure of patients to complete antibiotic therapy (globally)
influenza has a stable reservoir in ____
aquatic birds
name 4 examples of influenza pandemics
- 1918 Spanish flu
- 1957 Asian flu
- 1968 Hong Kong flu
- 2009 Swine flu
what influenza pandemic was the most significant?
1918 Spanish flu: 50,000,000 deaths worldwide
when are people with influenza most contagious?
- first 3-4 days
- adults may be infectious 1 day before symptoms develop, up to 5-7 days after
- young children & immunocompromised may be infectious for longer
what is the time from when a person is exposed and infected with influenza to when symptoms begin?
~2 days, or 1-4 days
when do flu antiviral drugs work best?
- when started within 2 days of getting sick
- starting later can be beneficial, especially if at risk of serious flu complications or in hospital with more severe illness
what are prions?
infectious protein particles
what do prions cause?
transmissible spongiform encephalopathies (TSEs)
history of TSE
- first seen in united kingdom, 1762: scrapie in sheep
- 1984: mad cow in cattle
- 2000: creutzfeldt-jakob disease in humans
describe how normal prions become abnormal
abnormally folded PrPsc
- aggregate into fibrous structures in the brain referred to as plaque
- disrupt the cell membrane causing cell death
- convert normal prions into abnormal prions
what is the prion hypothesis?
resistant to:
- cooking
- autoclaving
- strong alkali treatment
- disinfectants
survive in soil for years
what is TSE?
- neurodegenerative disease
- affects sheep, cattle, humans
- no test for it in living organisms
- no treatment or cure
pathogenesis of TSE
- long incubation time
- plaque deposits in brain
- no Ab response
- no inflammation
symptoms of TSE
- lack of coordination
- staggering
- slurred speech
- dramatic mood swings
- paralysis
- death within 1 yr of symptom onset
TSE presents in humans as ____ and ____
kuru
Creutzfeldt-Jakob disease
how is kuru spread?
cannibalism
how is the new variant of Creutzfeldt-Jakob disease spread?
food web
(possible epidemic)
