Microbiology Chapter 12.txt
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What ways is anthrax transmitted in nature?
Inhalation, Food born, Skin contact
Inhalation while working with sheep hides and wool. Resembles a common cold with fever, chills, chest pain, headache and malaise. Symptoms progress to severe breathing problems and shock. Usually fatal without treatment.
- Eating under cooked, contaminated food may lead to gastrointestinal anthrax. Initial signs include nausea, loss of appetite, vomiting and fever followed by abdominal pain, vomiting of blood and sever diarrhea. Death results in 25% to 60% of untreated cases.
- Cutaneous anthrax infect skin abrasions from violin bows, shaving bristles, drum heads, and leather jackets. Skin infection begins as a papule but withing 1-2 days it develops into a pustule of black, necrotic tissue that eventually crusts over.
Appraise the role of anthrax as an agent for bioterrorism
Anthrax spores could be distributed without early detection. It was distributed intentionally in through the US mail in 2001. If land is infected the spore remain viable for a very long time. Brittan experimented with an anthrax bomb on Gruinard island in 1941 and 45 years later the spores were still viable.
Describe the sequence of events that takes place when tetanus bacilli grow in the dead tissue of an infected wound.
- In dead, oxygen free tissue of a wound, the spores germinate in about 10 days to vegetative bacilli that produce several toxins. The most important toxin produced is tetanospasmin, the 2nd most powerful toxin known in science (after the botulism toxin). Tetansospasmin prevents the release of neurotransmitters needed to inhibit muscle contraction. This causes muscle spasms and stiffness.
- Symptoms of tetanus intoxification develop rapidly, often within hours of exposure. 1st experience generalized muscle stiffness, especially in the face and jaw. The teeth clench, called trismus or lockjaw.
Explain the difference between gangrene and gas gangrene
- Gangrene develops when blood flood ceases to a part of the body. The area becomes dry and shrunken and may turn purple or black. It spreads when enzymes from broken cells destroy other cells.
- Gas gangrene AKA myonecrosis is caused by Clostridium perfringenes. The spores enter a wound (usually from dirt into a severe wound) and begin to ferment the muscle carbohydrates and decompose the muscle proteins. Large amounts of gas may result from this metabolism. At least 12 exotoxins are produced, the most important being alpha-toxin which damages and lyses blood cells.
Write a short review of leptospirosis, including a description of the organism and some major symptoms of the disease.
- The most widespread of zoonosis - a disease that spreads from animals to humans
- Animals spread it from urine and humans can get it from walking thru the urine.
- Most people experience flu like symptoms, but 5-10% progress to a systemic, lethal form.
- In the first stage, there is an acute onset of heache, muscle aches, vomiting, and nausea. The eyes become very red. Fever and chills for 4-9 days then disappear.
- In the second stage, the immune system reacts to the spirochetes invading the system. Fever returns and meningitis is common. There may be inflammation in the liver and lungs. Kidney damage and jaundice may be present.
Name some occupations in which the individuals may be at risk for leptospirosis
Adventure travelers to distant, exotic locations, triathletes
Describe the characteristics of the plague organism and identify the three forms of plague, specifying how each is transmitted.
- Plague is caused by Yersinia pestis carried by rodents and their fleas.
- It's a nonmotile, G-, rod with bi-polar staining.
- Transmitted by the rat flea. The bacteria causes the fleas to be more hungry.
- When detected early, treated with tetracycline or streptomycin, 18% mortality.
Caught from fleas. The lymph nodes swell and form purplish blotches. Hemmorage rings on the skin. Blood pressure drops. 60% mortality without treatment.
The bacteria may spread to the bloodstream from the infected lymph nodes. It can progress to the lungs or lead to plague meningitis. 100% mortality w/out treatment
Human to human spread by respiratory droplets. Pneumonia like symptoms. Hemorrhaging and fluid accumulation. 100% mortality w/out treatment
Locate the different areas of the body that can be affected in tularemia and discuss the possible methods of transmission.
- AKA rabbit fever
- Can be acquired thru tick bits, infected rabbit meat, drinking contaminated water or inhaling contaminated air
- The place of infection develops a lesion (skin, eye, etc). Flu like symptoms
Outline the relevant features of Lyme disease, beginning with the responsible organism and mode of transmission and proceeding to symptoms and treatment
- Caused by Borrelia burgdorferi
- Transmitted by tick bite. The tick defecates in the bite and transmits the spirochete.
- Early localized stage: involves a slowly spreading rash called erythema migrans and the site of the tick bite. It begins as a small raised rash and increases in diameter over a period of weeks sometimes reaching 10-15 inches. Bulls-eye rash. 20%.
- Early disseminated stage: begins weeks to months later with the spread of Burrelia burgdorferi to the skin, heart, nervous system, and joints. Can lead to meningitis, facial palsy and peripheral nerve disorders. Cardiac abnormalities. Joint and muscle pain.
- Late state: if still untreated this occurs months to years later. Chronic arthritis. Swelling in large joints.
Explain why relapsing fever is so named.
Because infected individuals go through periods of fever and chills when many spirochetes are in the blood.
Compare Rocky Mountain spotted fever and epidemic typhus with respect to causative agent, transmission, symptoms, treatment and diagnosis.
- RMSF caused by Rickettsia rickettsii. Transmitted by hard ticks. Symptoms are high fever lasting many days, severe headache, skin rash that starts as pink spots and progresses to pink-red papules. Where they fuse they form maculopapular rash. Rash spreads from hands and feet to trunk.
- Epidemic typhus caused by Rickettsia prowazekii. Transmitted by body lice. Excreted in feces of lice, so scratching will facilitate infection into the bite. Maculopapular rash spreads from trunk to extremities. Intense fever for many days with hallucinations and delirious.
Discuss endemic typhus, focusing on its transmission and symptoms as they compares with epidemic typhus.
Caused by Rickettsia typhi. Spread by cat or mouse fleas. Mild fever, persistent headache. Maculopapular rash from trunk to extremities. Often no need for treatment.
Name and describe several rickettsial diseases that occur sporadically in human populations
- Scrub typhus: Asia and Southwest Pacific. AKA Tsutsugamushi fever. Mites in scrubland. Fever and rash
- Rickettsialpox: mice mites. Looks like chickenpox. Fever and rash
Inhaled anthrax causes a form of pneumonia that at first resembles a common cold (fever, chills, cough, chest pain, headache, malaise). After several days the symptoms may progress to sever breathing problems and shock. Usually fatal without early treatment.
A raised itch bump that resembles an insect bite
One of several toxins produced by Clostridium tetani. A neurotoxin
Lockjaw. Spasms of the jaw muscles cause teeth to clench.
Develops when blood flow ceases to a part of the body, usually as a result of blockage by dead tissue. The body part, generally an extremity, becomes dry and shrunken, and the skin color changes to purplish or black
- Myo= muscle, necros = death. AKA gas gangrene
- Caused by Clostridium perfringes
A disease of animals that can be spread to humans
In leptospirosis, damage to the kidneys and jaundice
Stains heavily at polar ends
A living organism that transmits disease agents
A substantial swelling in bubonic plague. Bubon = groin
Erythema migrans: red expanding rash. The bull's eye rash in Lyme disease
Refers to a lesion with a broad base that slopes from a raised center.
Believed to be a relapse of an earlier case of epidemic typhus in which R. prowzekii remains dormant in the patient. Milder symptoms
Bubonic plague bacteria
Lyme disease bacteria
Endemic typhus bacteria
Gas gangrene bacteria
Lyme disease bacteria
Epidemic typhus vector
Bubonic plague vector
Rabbits and rodents
Mites from mice
Endemic typhus vector
Lyme disease vector
- Endemic: Tick from rodents to humans
- Epidemic: body lice
How is Rocky Mountain spotted fever diagnosed?
Weil-Felix Ab test
What constitutes a positive test for rickettsial disease?
Proteus clumping of the bacterial cells
What causes epidemic typhus?
Epidemic typhus is transmitted by
Endemic typhus is also called
- Murine typhus.
- Murin = of the mouse
Rickettsia bacteria characteristics
Small, G-, non motile, obligate parasites.
Anthrax bacteria characteristics
G+ aerobic sporeforming bacillus with capsule
Clostridium tetani bacteria characteristics
G+ anaerobic sporeforming bacillus
Francisella telularemia bacteria characteristics
G-, small, aerobic rod
Borrelia burgdorferi bacteria characteristics
Leptospira interrogans bacteria characteristics
G-, thin, aerobic, coiled spirochete usually with a hook at one end
Yersinia pestis bacteria characteristics
G- bacillus, bipolar staining
Clostridum prefringes bacteria characteristics
G+ anaerobic sporeforming bacillus
Soilborne Bacterial Diseases
- Gas Gangrene
- Bacillus anthracis
- G+ aerobic sporeforming bacillus with capsule
- Found in soil
- Inhale spores or by contaminated meat
- Pulmonary anthrax: Hemorrhage or severe blood infection
- Skin anthrax: boil like lesions with black crusts leads to blood invasion
- Intestinal Antrax: diarrhea with bloody stools
- 80% mortality in untreated animals
- Treatment: penicillin
- Woolsorters disease
- Less than 12 cases from 1980 to 2000
- Clostridium tetani
- G+ anerobic sporeforming bacillus
- Found in soil, not highly invasive
- Spores enter deep wounds
- Exotoxin: neurotoxin-tetanospasmin
- Within a few hours
- Uncontrolled and sustained contractions esp. in face
- Trismus (lockjaw) involves spasms of the jaw muscle and clenching of the teeth
- Opisthotonus involves muscle spasms that cause an arching of the back
- Spasmodic inhalation and seizures in the diaphragm and rib cage
- Sedation, muscle relaxants, no muscle stimulation, penicillin, antitoxin
- Vaccination with a toxoid
- 150 cases per year in children and the elderly
- Clostridium perfringens
- G+ anaerobic sporeforming bacillus
- Produces Gas, Lecithinase
- Death frequent
Gas gangrene Symptoms
Intense pain, swelling, foul odor, anemia, possible heart and nerve damage
Gas gangrene treatment
- tissue debridement (maggots)
- exposure in a hyperbaric oxygen chamber
- Leptospira interrogans
- Transmission: urine to soil
- Colonize the kidney of infected animals
- Involvement in animals and workers
- Treatment with antibiotics
- The first phase involves flu-like symptoms and conjunctivitis
- The second phase involves:
- lung and liver inflammation
- kidney damage
- vomiting of blood
Arthropodborne Bacterial Diseases
- Bubonic Plague
- Lyme Disease
- Yersinia pestis
- G- bacillus, bipolar staining
- Transmitted by rat flea
- Blood disease
- Lymph nodes hemorrhage: bubos
- 50% mortality
- Water droplets
- Death within 48 hours
- 100% mortality
- Coughing, sneezing, fluid accumulation
Yersinia pestis Bacilli can spread to the bloodstream from the lymph nodes, causing:
- septicemic plague
- plague meningitis
Septicemic cases can progress to the lungs (pneumonic plague)
This allows human-human transmission through respiratory droplets to occur
Black plague Treatment:
- When plague is detected early, antibiotics can be used
- Tetracycline or Streptomycin
- Black Death
- 24 cases per year
- Vaccine is available
- Francisella tularensis
- Small G- bacillus with bipolar staining
- Carried by tick (vector)
- Found in rodents: rabbits
Tularemia Transmission via arthropod bite leads to:
- swollen lymph glands
- flu-like symptoms
- skin ulceration
Inhalation tularemia leads to:
- respiratory disease
- swollen lymph nodes
- pain under the breastbone
Ab and bacteria isolation
- Tetracycline or Streptomycin
- 200 cases per year
- Borrelia burgdorferi
- Carried by small deer tick
- Erytheme Chronicum Migrans (ECM)
Lyme disease Symptoms:
- Fever, headache, nausea
- Stiff joints, (arthritis)
- Low fatality
Lyme disease Treatment:
Penicillin or Tetracycline
Lyme disease Bacteria disseminate to the:
- nervous system
Rickettsial Arthropodborne Diseases
- Epidemic Typhus
- Rocky Mountain Spotted Fever
- Endemic Typhus
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