Lecture 14 Flashcards
1
Q
person-to-person transmission
A
- humans as disease reservoirs
- host-dependent pathogens
2
Q
barriers to transmission
A
desiccation and oxygen tolerance
3
Q
overcoming barriers
A
prevent desiccation through thick, rigid cell walls (gram + bacteria) and waxy layer of cell walls (mycobacterium spp.)
4
Q
airborne transmission
A
- travel through airborne particles (aerosols)
- causes respiratory diseases
- spread by sneezing, coughing, talking
5
Q
direct contact transmission
A
- physical contact or exposure
many human carriers - the compromised immune system increases the risk
6
Q
sexual transmission
A
- transferred during sexual activity from body fluids of the urogenital tract
- difficult to tract and control
- passage to newborns in infected mothers
7
Q
Airborne diseases
A
- streptococcus
- pertussis
- tuberculosis
- measles
- cold
- influenza
8
Q
Streptococcal diseases
A
- aerotolerant, gram +
- Strep throat (streptococcus pyogenes)
- Pneumonia (streptococcus pneumoniae)
9
Q
streptococcus pyogenes
A
- present in respiratory microflora (different strains with variable virulence)
- 11,000 deaths per year (15% mortality)
- lyses RBCs (rash)
10
Q
streptococcus pyogenes symptoms and diagnosis
A
- severe sore throat and mild fever
- untreated leads to scarlet fever
- use immunofluorescence, ELISA, throat cultures
11
Q
streptococcus pyogenes treatment
A
- no vaccine available
- antibiotics (penicillin G and erythromycin)
- early diagnosis and treatment is key!
- this infection on skin becomes flesh eating
12
Q
streptococcus pneumoniae
A
- present in lower respiratory microflora
- contribute to #1 killer worldwide (mortality is 10% when treated, 30% untreated)
- can spread as bacteremia
13
Q
streptococcus pneumoniae symptoms, diagnosis, treatment, and prevention
A
- reduced lung function (pneumonia)
- cultures (sputum, blood)
- vaccines available for high risk adults and children
- antibiotic treatment but only 30% of penicillin treatments work
14
Q
Pertussis (whooping cough)
A
- bordetella perutssis
- aerobic and gram -
- # 8 killer worldwide (distinction in death toll b/w developed and developing countries)
- adheres to upper respiratory tract
- produces exotoxins and endotoxins
15
Q
Pertussis (whooping cough) symptoms, diagnosis, and treament
A
- recurrent, violent cough
- PCR, culture, immunoassays
- vaccine available to high risk adults and infants (10yr immunity)
- antibiotic treatments but many strains are resistant
16
Q
tuberculosis
A
- myobacterium tuberculosis
- aerobic and gram -
- highly contagious and #4 worldwide killer
- acute v. chronic infections
17
Q
chronic tuberculosis
A
- most cases
- pathogen is dormant
- occasional post primary TB
18
Q
acute tuberculosis
A
- bacterial spread
- host damage, death
19
Q
M. leprae
A
- other mycobacteria pathogens
- causes leprosy
- “Hansen’s disease”
20
Q
M. bovis
A
- causes classic TB symptoms
- bovine to human transmission (eradicated w/ pastuerization)
21
Q
Measles
A
- paramyxovirus and negative-strand RNA virus
- mostly affects children and highly infectious
- # 6 killer worldwide
- enters nose and throat- systemic viremia
22
Q
Measles symptoms, diagnosis, and treatment
A
- early: nasal discharge, eye redness
- late: fever, cough, rash
- clinical symptoms, ELISA
- vaccine available for infants (MMR)
- treat symptoms
23
Q
Colds
A
- viral (many types)
- named because infection peaks in winter months
- primarily rhinoviruses
- most common infectious disease
- infects cells of upper respiratory tract
24
Q
colds symptoms, diagnosis, and treatment
A
- inflammation of the nasal region (rhinitis), watery nasal discharge, and malaise
- clinical symptoms as diagnosis
- no vaccine (too many different causative agents)
- treat symptoms (e.g. decongestants)
25
influenza
- orthomyxovirus group
- negative strand RNA virus
- 3-5 million severe cases
- infects upper respiratory tract
- leads secondary infections (how you die from flu)
26
influenza symptoms, diagnosis, and treatment
- fever, chills, headache, and malaise
- identify surface glycoproteins (hemagglutinin- attachment and neuraminidase- release)
- vaccines continuously produced due to changing H and N antigens
- antiviral drugs
27
direct-contact disease
- staphylococcal infections
- gastric ulcers
- hepatitis
- mononucleosis
28
staphylococcal infections
- staphylococcus aureus and MRSA
- facultatively aerobic, gram +
- microbiota of upper respiratory tract
- 85% of cases are health care associated
29
staphylococcal infections pathogenesis
- causes several disease (pyogenic infections, food poisoning, and toxic shock syndrome)
virulence factors:
- hemolysins, coagulase, leukocidin (lyses leukocytes), and enterotoxin A (super antigen)
30
staphylococcal diagnosis and treatmen
- enriched media cultures, for MRSA use chromogenic media
- treatment by exclusion of carries and antibiotics (differences in resistance)
31
gastric ulcers
- h. pylori
- microaerophilic, gram -
- highly motile
- present in 80% of gastric ulcer patients (but 80% are asymptomatic)
- may lead to gastric cancer
- attaches to stomach and duodenum lining
32
gastric ulcers symptoms, diagnosis, and treatment
- epigastric (stomach) pains
- use biopsy culture
- antibacterial (metronidazole)
- antibiotic (amoxicillin) + antacid
33
Hepatitis
- Hepatitis A, B, and C
- some bacteria
- #10 killer worldwide
- large declines due to vaccines
34
Hepatitis symptoms and diagnosis
- bloodborne and consuming infected shellfish
- jaundice and cirrhosis
- ELISA (most common), immunoblots, and PCR tests (no cultures)
35
Hepatitis prevention and treatment
- vaccines (HAV and HBV)
- IV drug reduction
- food/water sanitation
- supportive treatment
- antivirals for HBV and HCV
36
Mononucleosis
- Epstein-Barr viruses (EBV)
- double stranded DNA virus
- member of herpes viral family
- mortality low, morbidity over 90% worldwide
37
Mononucleosis pathogenesis, symptoms, and diagnosis
- infects salivary gland cells and b cells
- extreme fatigue, sore throat, fever
- diagnosis: microscopy (blood sample) and PCR tests
- no vaccine
- supportive treatment
38
sexually transmitted diseases
- gonorrhea v. syphilis
- chlamydia
- herpes
- AIDS
39
gonorrhea v. syphilis
- two common (gonorrhea incidence higher) and treatable STDs
- using penicillin
40
high incidence of gonorrhea reasons
1) strain-specific acquired immunity
2) use of oral contraceptives
3) mild symptoms in infected women
41
chlamydia
- acts similar to virus
- chlamydia trachomatis
- obligate intracellular bacterium
- most commonly reported STD in US
- #18 WW killer
42
chlamydia symptoms, diagnosis, and treatment
- inapparent in most cases
- rarely: testicular swelling and fallopian tube damage
- PCR tests and ELISA
- antibiotics (azithromycin and doxycycline)
43
herpes
- diverse, dsDNA virus group
- herpes simplex 1-- cold sores
- herpes simples 2 -- genital blisters
- genital herpes (HSV-2) is incurable
44
AIDS
- HIV and a retrovirus
- recognized in 1981
- 2.7 million cases annually
- a lot of deaths
45
AIDS pathogenesis
- virus targets T cells and macrophages using gp120 protein
- viral replication -> immune cell death
- syncytia = fused healthy + infected host cells
-- accelerates infection and destruction of host cells
46
AIDS symptoms, diagnosis, and treatment
- early: none or flu-like
- late: strong and variable (results from opportunistic infections)
- diagnosis: ELISA+ immunoblot
- no vaccine and no cure
- drugs to delay disease progression
