Diseases 5 Flashcards
List and describe the three main types of influenza. Subtype vs. strain.
3 types
Influenza A
Broken into subtypes: based on glycoproteins present- hemagglutinin (H) and neuraminidase (N)
Subtypes broken into strains
Cause of major pandemics
Influenza B
Infects humans only (geographic epidemics)
Broken into strains
Influenza C
No epidemics-mild disease
Infects humans and pigs
What is the (general) cause of the disease? What is the main reservoir (of subtypes)? Disease “mixing pot?”- influenza
- Influenza A is found in many different animals, including ducks, chickens, pigs, whales, horses, seals, cats, and humans
Orthomyxovirus- RNA virus
Replication strategy- 8 pieces of RNA for type A/B only 7 pieces for type C
RNA virus- high mutation rate (due to no proofreading of polymerase- faulty enzyme)
Therefore, evolves quickly (yearly drift)
Influenza A
16 H subtypes and 9 N subtypes (available)
Therefore, many combinations of proteins
Most subtypes found in birds- main natural reservoir
Pigs can be infected with both human and avian influenza viruses in addition to swine influenza viruses
i. Therefore main micing pot (can have mixing in humans also)
How is the disease organism transmitted?- influenza
Droplet
Respiratory tract (50,000- 500,000 virus/droplet)
Fomites (nonliving object- spread infection)
Touch nose
Touch mouth
Describe antigenic shift (leads to what??) and antigenic drift (leads to what??).- influenza
- Antigenic Shift
o pigs infected with human, bird, and pig virus
o can mix genes
o completely new subtype- so no resistance in the population
o only happens occasionally
o new pandemic possible
- Antigenic Drift
o RNA virus mutates in host
o Slight resistance in population
o Happens all the time
o Get new strains yearly
o Influenza B can only drift not shift
o Influenza A can do both
How is human death different from shift vs. drift?
Shift
Death in healthy adults
Death due to hemorrhagic pulmonary edema
i. Immune system is too good- freak out
Drift
Death in elderly and immunocompromised
Death due to secondary infections or underlying health conditions
Know some severity of the disease information (deaths/year in the US, hospitalizations).- influenza
- An average of 36,000 people die from flu-related complications in the US
- 200,000 people are hospitalized from flu related causes
- Children under 5 and adults older than 65 are main targets
What are some prevention methods (vaccine information)?- influenza
- Seasonal vaccine typically against H3N2, H1N1, strains, and influenza B strain
o Quadrivalent
o Injected- inactivated/”dead” influenza virus
o Nasal spray- attenuated virus/ weakened virus- stopped production now
- Wash hands with soap and water
- Avoid touching eyes. Nose or mouth
- Cover nose and mouth when coughing/sneezing
- Avoid close contact with sick people
- Sick- stay at home for 24 hours until fever is gone
What is the cause of AIDS?
HIV
List some characteristics (special enzymes) and some information about the structure of the virus? - AIDS
- Retrovirus
- Genus- Lentivirus
- 2 identical strands of RNA
- Reverse transcriptase enzyme (RT)
- envelope
List and give some characteristics (originated from) of the two types of the virus.- AIDS
- HIV is a mutation of Simmon immunodeficiency virus- (SIV)- 1908
- First documented case
o 1959- man from republic of congo
o Blood sample- ability to travel caused to spread
- 1978-1981 in the US
o Rare types of pneumonia and cancer
o Reported in Los Angeles and new York
o Patients had loss of immune function
- 1983 had identified pathogen
o HIV 1- US- chimps
o HIV 2- Africa- monkeys
How is the virus transmitted? -AIDS
- Sex (anal, vaginal, oral) with infected person
- Shared needles or injection equipment with infected person
- HIV-infected women to babies before or during birth and during breastfeeding
List some information about the virus life cycle (steps it takes to make more viruses). - AIDS
- Virus attaches to CD4 receptors of cells- helper T cells (main) , macrophages, dendritic cells
- Capsid enters cell by fusion
- Uncoating of capsid
- Viral RNA reverse transcribed into DNA
- Viral DNA integrates into host chromosomal DNA
- DNA may produce new HIV which Bud from cell
o Or may not produce new HIV
- Latent viruses in some cells
What are some prevention/treatment methods used for the disease? A vaccine?- AIDS
- No vaccine
- Education- promote abstinence, discourage promiscuity, promote condom use, no drug use
- Drugs to manage symptoms but no cure
o Highly active antiretroviral therapy
§ Involves using a combination of drugs
§ RT inhibitors
§ Protease inhibitors
§ Fusion inhibitors
§ Integrase inhibitors
What is the cause of whooping cough and some characteristics of this organism?
- An acute and highly contagious bacterial disease that affects the respiratory system
- gram negative coccobacillus
- aerobic
- fastidious
What are the stages of the disease?- whooping cough
- Incubation period
o 7-10 days
- Phase 1 (catarrhal)
o Cold-like symptoms
- Phase 2 (paroxysmal)
o Severe coughing “attack”, whooping sounds (gasping for air), and vomiting
- Phase 3 (convalescent)
o Recession of previous symptoms
- Broken blood vessels due to coughing
