Diseases

Question 1

Hepadnaviridae; dsDNA, envelopes, 42nm. 70% asymptomatic. 30%: jaundice, right quadrant pain, 90% self-resolve. Antiviral drugs if necessary. Vaccine; immunoglobulin available.

Answer 1

Hepatitis B

Question 2

Acid-fast rod. Airborne. Forms calcified tubercles in alveoli which rupture when immune system weakens. 6-month course of treatment. 33% of world population infected. Inconsistent vaccine effectiveness; not recommended in US.

Answer 2

Mycobacterium tuberculosis

Question 3

Gram+; spore-forming; primarily zoological but can infect humans (inhalation, cutaneous, gastrointestinal). Negatively-charged capsule inhibits phagocytosis.Inhalation widens mediastinum. 22 terrorist-caused cases in 2001. Annual vacines available.

Answer 3

Bacillus anthracis

Question 4

Acid-fast, Gram+ bacillus.Obligate parasite attaches to Schwann cells. Tuberculoid (mild) or Lepromatous (severe); mainly affects skin & nerves. Incubation period 3-5 years. Airborne. 90% of infections sucessfully defeated by immune system; no vaccine available.

Answer 4

Mycobacterium leprae

Question 5

Gram- bacilli grow as biofilms on skin, in soil and water. Produces endotoxin and exotoxin. Antibiotic- and chlorine-resistant, causes swimming-associated rash; frequent nosocomial infections.

Answer 5

Pseudomonas aeruginosa

Question 6

Gram+ spore-forming normal microflora. Triggered by antibiotic use, mainly in health care settings. Intestinal infection: diarrhea is body’s attempt to rid itself. Easily transmitted on hands and surfaces.

Answer 6

Clostridium difficile

Question 7

dsDNA enveloped virus, pleiomorphic, 120-200nm. Target protein receptors on cell membrane and colonizes nerve cells near spinal cord. Usually asymptomatic; can cause fluid-filled blisters. Antiviral medications.

Answer 7

Herpesviridae

Question 8

Gram+ cocci, cluster arrangement. Targets host cell membranes to cause skin and other infections. Multi-drug resistant opportunistic pathogen; normal nasal/skin flora.

Answer 8

Staphylococcus aureus

Question 9

Gram+ spore-forming bacilli found in soil (spores) and in animal GI tracts. Produces 2 exotoxins; one (very potent) attaches to nerves & blocks neurotransmitter release to CNS causing chronic contraction, usu. beginning with neck & jaw muscles. Spores or bacteria enter wounds, but can only grow in anaerobic environment. Vaccine requires 5-year booster; no permanent immunity. Terminal endospores produce drumstick appearance.

Answer 9

Clostridium tetani

Question 10

Non-enveloped polyhedral virus; over 100 strains (30 carcinogenic). Skin/mucous membrane infections. Proteins inactivate host’s tumor suppressor protein and cause uncontrolled cell division. Cancerous strains often asymptomatic. Usu eliminated by immune system prior to infection. Cell-mediated immunity failure delays activation of adaptive immunity. Over 110 million infected.

Answer 10

Human papillomavirus

Question 11

Spore-forming Gram+ rod found in soil, moist sediment, and on fruits, veggies, seafood. Obligate anaerobe produces 2 exotoxins (very potent) which act at the neuromuscular junction to prevent aCh release, cause flaccid paralysis 7 toxigenic strains Mostly ingested; sometimes cutaneous. Extremely llethal. Antitoxins can have serious side effects. No immunity from exposure.

Answer 11

Clostridium botulinum

Question 12

Capsulated Gram- diplococci. Usu affect the genitourinary tract, sometimes the pharynx or rectum. 50% females & 10% males asymptomatic.

Answer 12

Neisseria gonorrhoeae

Question 13

Large brick-shaped virus localized in mouth, throat, and small blood vessels of skin. SPICE protein is virulence factor. Contact with infected items, fluids, occasionally airborne. Grows on mucous membranes, multiplies in lymph nodes, enters bloodstream. Causes pus-filled blisters that become pitted scars. Vaccines activate humoral & cellular immunity but lasts only 3-5 years.

Answer 13

Variola minor: Smallpox

Question 14

Positive ssRNA virus; enveloped; spherical with spikes. Causes liver inflamation and cancer. 15-25% will clear the virus without treatment or chronic infections. No vaccine but immunity may exist. Multi-drug therapy necessary.

Answer 14

Hepatitis C virus

Question 15

Helical ssRNA virus, very long, membranes stolen from host cell by budding. Systemic disease causes hemorrhagic fever and blood vessel damage, tuns course quickly. Transmitted through contact with infected patient, no treatment - 50-90% mortality.

Answer 15

Ebola virus

Question 16

Abnormally folded infectious proteins, no DNA or RNA. Induce the formation of an amyloid fold, creates transmissible spongiform encephalopathies. CJD, Kuru. No treatment. Sporadic, hereditary, acquired (consumption)

Answer 16

Prion Diseases

Question 17

Gram- bacilli produce toxin, penetrate epithelial lining of intestines. Experimented as biological weapon. Transmitted through exposure to contaminated feces.

Answer 17

Shigella dysenteriae

Question 18

Gram- spirochete only affects humans. Sexual contact transmission. Causes sores and leisions; treated with penicillin.

Answer 18

Treponema pallidum: syphilis

Question 19

Gram+ bacilli produce exotoxins; Highly contagious, transmitted airborne or cutaneous. Affects mcous membranes and distributed toxin through blood. Causes paralysis or heart failure. treat with antibiotic & antitoxin. Vaccination with toxoid every 10 years, historically a childhood disease.

Answer 19

Corynebacterium diptheriae

Question 20

Spherical virus, 2 layers of spikes. Three types (A/B/C) spread through mammalian contact. Pandemic type fast-mutating. Antiviral reduces severity. No vaccines and no immunities due to rapid mutation.

Answer 20

Influenza virus

Question 21

ssRNA virus passed from animal saliva to human through broken skin; causes brain & CNS infections; alters neuron function. CNS route allows virus to avoid immune system. Treatment with vaccine prior to CNS infection necessary for survival. No natural human immunity.

Answer 21

Rabies virus

Question 22

Gram- bacilli produces exotoxins. Dormancy is virulence factor. Passed through fecal-contaminated water, eliminated in feces. Infects intestine, sensitive to stomach acid. Rice-water stool, severe dehydration. Treat with antitoxins, antibodies, immunization in high-risk areas. 7 historical pandemics.

Answer 22

Vibrio cholera.

Question 23

Gram- spirochete passed rodents->ticks->humans. Increased virulence: doesn’t need iron to live. Bulls-eye rash, no treatment can lead to meningitis, encephalitis, palsy, paralysis, neurological diseases. Treat with antibiotic. Manganese neutralizes lysosomes & inhibits macrophages.

Answer 23

Borrelia burgdorferi: Lyme disease

Question 24

Gram- bacilli, flatellated facultative anaerobe. Only in humans, usu gall bladder and bile ducts. Excreted in urine & feces, transmitted through contaminated food or water. Mostly acquired during international travel, causes systemic infections. Acquired immunity more effective than innate, strong antibody response participates in protection. Involves T & B cell-mediated immunity. Vaccine available.

Answer 24

Salmonella typhimurium: Typhoid fever.