Spirochetes have a helical form. The majority of spirochetes are free-living saprobes or commensals of animals and are not primary pathogens. They are motile, gram-negative, and have enclosed flagella. They multiply quickly as you can see. Corkscrew-shaped bacteria. Bacteria are simple, unicellular organisms that are classified in the kingdom Monera (also called kingdom Prokaryotae). They have prokaryote cells, which means that they lack a nuclear membrane and other complex features. They move by means of two or more axial filaments, which are bundles of fibers that spiral around the cell body. Spirochetes show no evidence of any sexual life cycle and reproduce asexually by transverse fission, in which the organism divides in two across its width.


Three spirochetes - human pathogens

• Treponema- thin, regular, coiled cells. They don't live freely in the environment; humans are the natural host. Extremely fastidious & sensitive. Treponema lives in the oral cavity, intestinal tract & perigenital region.Causes syphilis (both venereal and congenital). These are parasites and if you want to cultivate them in a lab you need to do it on live cells.They stain very poorly because their thickness approaches the resolution of the light microscope. They are delicate organisms requiring pH in the range 7.2 to 7.4, temperatures in the range 30°C to 37°C and a microaerophilic environment.
• Leptospira- tight, regular individual coils with a hook at both ends. Bacteria found in urine of many different animals. Also found in skunks. Infection occurs from contact. Mainly tropical. It is caused by bacteria of the genus Leptospira. In humans it causes a wide range of symptoms, and some infected persons may have no symptoms at all. Symptoms of leptospirosis include high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash. If the disease is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress. In rare cases death occurs.
• Borrelia- large, 3-10 coils. Infection transmitted by vectors such as ticks or lice. Causes lyme disease. Can progress to cardiac and neurological damage. Borrelia burgdorferi, also referred to as Lyme Disease is caused by a spirochete. Lyme disease is typically carried by the lxodes family of ticks. These include the deer tick. This gram-negative bacterium is stained by ordinary dyes such as crystal violet and carbofuchsin.

TREPONEMA PALLIDUM

-Humans are the only host and the bacteria cannot survive very long without humans. They are very sensitive, easily destroyed by heat, drying, disinfectants, soap, high oxygen, and pH changes.They can live in the oral cavity, intestinal tract, and perigenital regions of humans.
-Causes of syphilis are: mainly spread through sexual contact. Can be spreed to a fetus in utero. Medical personel can get from contact with body fluids.
-The pathogens are very strict parasites with complex growth requirements that necessitate cultivating them in live cells.
-Brought into direct contact with mucous membranes or abraded skin, binds avidly by its hooked tip to the epithelium
-At the binding site, the spirochete multiplies and penetrates the capillaries. Within a short time, it moves into the circulation, and the body is literally transformed into a large receptacle for incubating the pathogen--virtually any tissue is a potential target.
-Produces no toxins and does not kill cells directly. Despite action of phagocytes and antitreponemal antibodies, the body's cell mediated immune responses are unable to contain it.
-Infectious dose is 57 organisms (low dose compared to other bacteria)
-Very effective treatment is Penicillin G


SYPHILIS
History of Syphilis
Spirochette syphillis on the head of a sperm
Syphilis was first recognized at the close of the fifteenth century in Europe. Outbreaks followed Columbus' return from the New World (he did more than look for gold and spices on his trip...what happens in the New World stays in the New World).

-Syphilis is mainly spread through an infected sexual partner and the risk of transmitting it is 12% to 30%
-Reported cases have decreased in the last decade, but in some populations it is increasing largely among the gay and bisexual population or men in large urban areas. Also in larger metropolitan areas among prostitutes, their contacts, and intravenous drug users.
-Specific factors that account for the virulence of the syphilis spirochete appear to be the outer membrane proteins.
-At the initial point of contact the bacteria multiplies, penetrates the capillaries , and enters the circulation system. The body then becomes a large incubation chamber for this bacteria and virtually any tissue is a potential target. It produces no toxins and does not kill cells directly. Despite action of phagocytes and antirreponemal antibodies, the body's immune system is unable to contain it. During the incubation stage there are no symptoms (this lasts about three weeks), but in the next two stages it makes its self known.
-Untreated syphilis is marked by distinct clinical stages designated as primary, secondary, and tertiary syphilis. Also has latent periods of varying durations during which the disease is quiescent.

Q: Which of the following is not a factor that contributed to the worldwide transmission of syphilis that began in the latter 15th century?
a. The evolution of Treponema pallidum from a related subspecies.
b. Sailors returning with Christopher Columbus from the West Indies brought the disease with them.
c. The European population was sexually promiscuous during this period.
A: Sailors returning with Christopher Columbus from the West Indies brought the disease with them.

Stage	Average Duration	Clinical Setting
Incubation	3 weeks	No lesion; treponemes adhere and penetrate the epithelium; after multiplying, they disseminate
Primary	2-6 weeks	Initial appearance of chancre at inoculation site; intense treponemal activity in body; chancre later disappears(small red bumps). Breaks down and leaves a shallow crater with firm margins, usually on genitals but can also leave on: lips, oral cavity, nipples, fingers and rectum.
Primary latency	2-8 weeks	Healed chancre; little scarring; treponcemes in blood; few if any symptoms. Bacteria still remains busy.
Secondary	2-6 weeks after chancre leaves	Skin, mucous membrane lesions; hair loss; patient highly infectious, fever, headache, sore throat, lymphadenopathy; followed by a full body rash, this are spirochetes. This is the stage that patients are most infectious.symptoms can persist for months
Latency	6 months to 8 or more years	Treponemes quiescent unless relapse occurs; lesions can reappear
Tertiary	Variable, up to 20 years	Fatal to organs if it reaches this stage. aortic wall could rupture, tumors develop,Brain, cranial nerves, spinal cord, Neural, cardiovascular symptoms; gummas develop in organs; seropositivity

PRIMARY SYPHILIS [first stage]:

-3 weeks after initial contact
-Appearance of a hard chancre (the primary sore of syphilis that forms at the site of penetration by treponema pallidum. It begins as a hard, dull red, painless papule that erodes from the center). The chancre enlarges and breaks down, leaving a shallow crater with firm margins.
-Mostly chancres appear on the internal or external genitalia, but about 20% occur on lips, nipples, fingers, or around the anus.
-Tend to be painless so chancres can be unnoticed
-Lymph nodes draining the affected region become enlarged and firm, but systemic symptoms are usually absent.
-The chancre spontaneously heals without scarring in 3-6 weeks, but healing is deceptive, because the spirochete has escaped into the circulation and is entering a period of tremendous growth.
-You can diagnose the primary stage of syphilis through a dark-field microscope
-Treatment is Benzathine, Penicillin G, Aqueous Benzyl, or Procaine Penicillin.

SECONDARY SYPHILIS [second stage]:
-2 to 8 weeks after chancre leaves.
-By now many systems of the body have been invaded, and the signs and symptoms are more profuse and intense.
-Skin, mucous membrane lesions; hair loss; fever, headache, and sore throat, followed by lymphadenopathy and a peculiar red or brown rash that breaks out on all skin surfaces, including palms and soles.
-Like the chancre. the lesions contain viable spirochetes and disappear spontaneously in a few weeks.
-Major complications, occur in the bones, hair follicles, joints, liver, eyes, and brain, can linger for months and years.
- Patient most infectious at this stage.
-Diagnose with dark-field testing; serological tests (+)
-Treatment is just double doses of penicillins listed above.

TERTIARY SYPHILIS [third stage]:
-After resolutions of secondary syphilis, about 30% of infections enter a highly varied latent period that can last 6 months up to 20 years or even more.
-Antitreponeme antibodies are detected but not the parasite itself.
-The final stage of disease is quite rare today because of widespread antibodies to treat other infections.
-When patient reaches this phase, numerous pathological complications occur in susceptible tissues and organs.
-Cardiovascular syphilis results from damage to the small arteries in the aortic walls. (the walls weaken
and the aorta is subject to distension and fatal rupture, and may damage the aortic valves causing heart
failure)
-Painful swollen syphilitic tumors called gummas (a nodular, infectious granuloma characteristic of tertiary syphilis) develop in tissues such as liver, skin, bone, and cartilage.
-Gummas are usually benign and only occasionally lead to death, but can impair function.
-Neurosyphilis can involve any part of the nervous system, but shows particular affinity for the blood vessels in the brain, cranial nerves, and dorsal root of the spinal cord.
-Reactions include severe headaches, convulsions, mental derangement, atrophy of optic nerve, blindness, and the Argyll-Robertson pupil (small pupils that do not react to the light, and is perhaps the most common sign)
-Destruction of part of the spinal cord leads to muscle wasting and loss of activity and coordination.
-Diagnosis: Treponeme may be demonstrated by DNA analysis of tissue
-Treatment is the same as secondary syphilis.

CONGENITAL SYPHILIS: (passage through placenta)
-Treponema pallidum can pass from a pregnant women's circulation into the placenta and be carried throughout the fetal tissues.
-Can occur in any of the three trimesters, though most common in the second or third.
-The pathogen inhibits fetal growth and disrupts critical periods of development with varied consequences, ranging from mild to the extremes of spontaneous miscarriage or stillbirth.
-Usually first detected 3 to 8 weeks after birth.
-Infants show signs of profuse nasal discharge, skin eruptions, bone deformation, and nervous system abnormalities
-The late form gives rise to an unusual assortment of stigmata in the bones, eyes, inner ear, and joints and causes the formation of Hutchinson's teeth (notched, barrel-shaped incisors)

Diagnosing: One rapid, direct method to detect primary, early congenital, and, to a lesser extent, secondary syphilis, is dark-field microscopy of a suspected lesion. Lesions are gently squeezed or scraped to extract clear serous fluid. A wet mount prepared from the exudate is then observed for the characteristic size, shape, and motility of T. pallidum. A single test is not 100% because the patient may have removed the organism by washing, so follow up tests recommended.
-Also a immunofluorescence staining with monoclonal antibodies give a direct test.
-Patient samples can also be tested with a DNA probe specific to various gene sequences.
-If microscopy tests are negative, serological tests looking for presence of antibodies can be diagnostic (but false positive results are possible)
(A) This is tested in premartial blood tests
(B) This is suggested for people in high risk groups
(C) If a patient tests positive, there are more specific tests that can verify an active infection.

Treatment:
-Originally no good treatment, Mercury was used (unfortunately the treatment was worse than the disease)
-Paul Ehrlich developed Salvarsan in 1910
-Penicillin in the 1940's
-Penicillin G is the wonder drug and treatment in all three stages. If allergic to penicillin they will administer tetracycline and erythromycin. Public health departments and physicians are charged with the task of questioning the patients and tracing their contacts. Those people, even if they don't show any signs of syphilis will immediately be given penicillin
-Important to complete the course of antibiotics (at least 7 days)
-Condoms provide good protection
-Vaccine may be available in the future

A NOTE ABOUT A DARK EVENT IN HUMAN EXPERIMENTATION (Kevin did mention this in class)
-One of the most disturbing events in the study of syphilis in the US. In 1932, the US government conducted a study called the Tuskegee Study of Untreated Syphilis in the Negro Male, which eventually involved 399 indigent African-American men living in the South. Infected men were recruited into the study, which sought to document the natural progression of the disease. These men were never told they had syphilis, and were never treated, even after penicillin proved to be an effective cure. The study ended in 1972, after it became public. In 1997, the government issued a public apology for permitting the study to proceed for so long, and began paying millions in compensation to the victims and their heirs.
*2006 cdc statistics
LEPTOSPIRA:


-Marked by tight, regular, individual coils with a bend or hook at one or both ends.
-Only two species in the genus:
-Leptospira interrogans (which causes leptospirosis in humans and animals a zoonosis, such as rodents), and
-Leptospira biflexa (a harmless, free-living saprobe).

These two species are serologically, genetically, and physiologically distinct
-Leptospirosis is a zoonosis (an infectious disease indigenous to animals that humans can acquire through direct or indirect contact with infected animals)
-Skunks, rodents, raccoons, foxes and some domesticated animals; horses, dogs, cattle, and pigs.
-All over the world but mostly in the tropics
-Leptospira interrogans is the one that shed in the urine of an infected animal and can survive in the soil or water for several months (*remember the picture with the cow peeing and the guy laying in the grass behind it.)
-Infections occur almost entirely through contact of skin abrasions or mucous membranes with animal urine
-Not associated with bites, inhalation, or human contact
-In US 50-60 cases per year reported among older kids, and young adults expose to polluted water, and soldiers involved in jungle training.
-Sudden high fever, chills, headache, vomiting are early symptoms
-Damage to kidneys, liver, brain, and eyes if left untreated

Q: How are Leptospira species transmitted from their animal reservoirs to humans?
a. Animal bites
b. Contact with urine from an infected animal
c. Human contact with infected animals
A: Contact with urine from an infected animal

Diagnosis: A fast, specific, effective test call the macroscopic slide agglutination test is most often employees for routine screening. Then live or formalized L. interrogans is mixed with the patient's serum and observed for agglutination or lysis with a dark-field microscope.

Treatment: Early treatment with penicillin or tetracycline reduces symptoms and shortens the course of disease. But delayed therapy is less effective. Strain-specific vaccines made from killed cells are available but these can confer protection only to a specific endemic strain. Vaccination aimed toward combat troops training in the jungle and animal care and livestock workers. The best controls are to wear protective footwear and clothing and to avoid swimming or wading in livestock watering pools.

BORRELIA:

-Distinct from other pathogenic spirochetes. They are lager, and contain 3-10 irregularly spaced, loose coils with many periplasmic flagella
-Human infection is transmitted by some type of arthropod vector, usually ticks or lice
-The two most important diseases caused by borrelia are relapsing fever and Lyme Disease

Relapsing fever
-Usually caused by ticks, but can be spread by squirrels, chipmunks or other wild rodents. [The human is usually an accidental host]
-Tick-borne relapsing fever occurs sporadically in the US but the incidence of infection is higher in tropical areas. Whenever famine, war or natural disasters are coupled with poor hygiene, crowding and inadequate medical attention, the incidence rises.
-The disease begins with a 2-15 day incubation period, causing the host to experience high fever, shaking, chills, headache and fatigue. It progresses to include nausea, vomiting, muscle aches and abdominal pain. Extensive damage to the liver, kidneys and cranial nerves occur in many cases. 50% of patients hemorrhage into organs, and some develop rash. Untreated cases may have a 40% mortality rate.
-The immune system has a difficult time trying to control relapsing fever, since the surface antigens change during growth. This means the initial antibodies produced by the body become useless.
-Blood smears are used to diagnose
-Chloramphenicol, erythromycin and doxycycline are used as treatment



Lyme Disease
-Is caused by Borrelia burgdorferi
-Transmitted mainly by hard ticks
-The cycle of Lyme disease: (complex 2-year cycle involving mice and deer)
1-Newly hatched larvae become infected when they feed on small animals such as mice, which harbor the spirochete. The larvae continue development through this year.
2- In the second year the larvae molt into the nymph, an aggressive feeding stage.
3- The nymph takes blood from a number of hosts, including deer and humans.
4- On deer, the nymph matures into adult male and female ticks, which mate. The female lays eggs in plant litter, where they hatch and once again begin the cycle
-Incidence showing upward trend with greatest concentrations in areas having high number of mice and deer.
-Lyme disease is non-fatal but often evolves into slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions
-An early symptom in 50% to 70% of cases is a rash at the site of a larval tick bite. The lesion, called erythema migrans, can appear something like a bull's eye
-Begins as tick bite and rash, progresses to fever, headache, stiff neck, and dizziness.
-After weeks or months, it can attack joints, cardiac and neurological symptoms (facial palsy) develop and some people acquire chronic neurological complications that are severely disabling
-Diagnosis can be difficult. Blood tests and serum tests are used for earlier stages, and spirochetal DNA tests are used for late-stage diagnosis
-Dogs can also acquire Lyme disease. There is a vaccine for dogs, but the vaccine for humans has been discontinued. Use DEET spray when going into areas where ticks may be!
-Early treatment with tetracycline and amoxicillin is effective
-Later treatment other antibiotics such as ceftriaxone and azithromycin are used.
Precaution measures to avoid Lyme disease
- it is suggested to use deet however this is not as helpful as many would think, from personal experience it seems to have little or no effect on ticks.
- The best preventive measure is to do regular tick checks. while in the field ocasoinally check your clothes to find the tick before they make contact with your skin. Also do a good check all over your body when you are at home when you can remove your clothes.
- Another thing that helps is wearing pants, boots, and long sleeve shirts so you have a better chance finding the ticks before they make contact with your skin.
http://www.cdc.gov/Features/LymeDisease/
ticks
Q: How are Borrelia species able to evade the immune system and avoid destruction in infected humans?
a. They have a capsule that makes phagocytosis difficult.
b. They remain inside the arthropod vector and are never exposed to the immune system.
c. They alter their surface antigens during growth.
A: They alter their surface antigens during growth.

CURVIFORM GRAM-NEGATIVE BACTERIA AND ENTERIC DISEASES

VIBRIO CHOLERAE


-Characteristics: Comma-shaped rods, with a single polar flagella

-The cause of Cholera
-Shares many characteristics with Enterobacteriaceae
-Can be free-living in certain endemic regions
-It ranks among the top seven causes of morbidity and mortality, affecting millions of people in endemic regions of Africa and Asia.
-Spread in the US mainly by contaminated food and water
- After being ingested with food or water. V. cholerae uses several virulence factors to help it survive the acidity of the stomach:

-The size of infection dose is 10^8 cells, due to the hostile environment
-Certain types of food might shelter the pathogen through the stomach environment
-An enterotoxin called cholera toxin (CT) disrupts the physiology of intestinal cells. When the toxin binds to certain intestinal receptors, a second system is activated and the intestinal cells shed large amounts of electrolytes. This causes profuse water loss.

-The vibrios penetrate the mucous barrier at the duodenum and jejunum, and rest near the surface of the epithelial cells. They are strictly epipathogens and do not invade the mucosa or enter the cells
-Most dangerous in elderly or very young
-After and incubation period of a few hours to a few days, symptoms begin abruptly with vomiting, followed by copious watery feces called secretory diarrhea (contains flecks of mucous, hence "rice-water stool")
-Fluid losses are nearly one liter per hour in severe cases and an untreated patient may lose up to 50% of body weight during the course of this disease.
-Cases "rice-water" stools, acidosis, potassium depletion, and blood loss in addition to dehydration that causes the patient to have muscle cramps, severe thirst, flaccid skin, sunken eyes, and in some children, coma and convulsions
-Secondary circulatory problems include hypotension, tachycardia, cyanosis, and collapse from shock within 18 to 24 hours
-If left untreated death can occur in less than 48 hours, and mortality rate approaches 55%.
-V. Cholerae can be clinically diagnosed in epidemics, but can also be identified in the lab from stool samples or direct dark-field microscopic observation. V. Cholerae have curved cells with brisk, darting movements
-Treatment is prompt replacement of h2o and electrolytes, tetracycline and some sulfa can stop diarrhea
ORAL REHYDRATION THERAPY: consists of a mixture of electrolytes sodium chloride, sodium bicarbonate, potassium chloride, and glucose or sucrose dissolved in water. When administered early in amounts ranging from 100 to 400 ml/hour, the solution will restore patients within 4 hours. Patients who are unconscious or with severe dehydration will need IV therapy.



Other Vibrio:
-salt-tolerant inhabitants of coastal waters, associate with marine vertebrates.
-Vibrio - gastroenteritis from raw seafood
-Vibrio vulnificus- gastroenteritis from raw oysters.

Helicobacter pylori

-H. pylori thrives in the acidic stomach environment
-peptic ulcers
-Causes inflammatory condition called gastritis as well as 90% of stomach and duodenal ulcers, an apparent co-factor in the development of adenocarcinoma of the stomach
-First detected in 1979 in patients with stomach ulcers by J. Robin Warren. They actually swallowed a good-sized inoculum and both developed a short-term of gastritis. He and his assistant, Barry J. Marshall, were awarded the Nobel Prize in 2005 for their discovery
-Occurs in stomachs of 25% of healthy middle-aged adults and more than 60% of healthy adults over 60
-Probably transmitted person to person by the oral-oral or oral-fecal route. May be spread by houseflies acting as mechanical vectors
-Seems to be acquired early in life and carried asymptomatically until its activities begin to damage the digestive mucosa.
-First it bores through outermost mucus that lines the epithelial tissue, then it attaches to specific binding sites on the cells and then entrenches itself.
-H. pylori shares the same receptor as the O blood type, which means that type O blood have a higher rate of ulcers
-Another protective adaptations the formation of urease, an enzyme that converts urea into ammonium and bicarbonate, both alkaline compounds that can neutralize stomach acid.
-appears to be a cofactor in a stomach cancer
-Diagnosis: H. pylori is isolated from biopsy specimens. Because it gives off large amounts of urease, it can be initially identified by inoculating a test that detects pH changes.
-A less invasive technique is the urea breath test. This test involved swallowing labeled urea that gives off radioactive CO2 in exhaled air if H. pylori is present. Hence, diagnosis can be made with a breath test.
-Treatment: Gastritis and ulcers have traditionally been treated with drugs (tagamet, zantac). They must be taken continuously for indefinite periods and relapses are common. The newest recommended therapy is 2 to 4 weeks of clarithromycin to eliminate the bacterial infection, and drugs that inhibit the formation of stomach acid. this regimen can actually cure the infection and eliminate symptoms.

Campylobacter jejuni
-Slender, short spirals or vibrios with one or more flagella. Often appear S-shaped
-Considered one of the most important causes of bacterial gastroenteritis worldwide.
-In US 2.5 million cases occur every year.
-Common in poultry flocks, this bacterium has become the leading cause of bacterial food-borne diseases in the US. Exposure to a small number of microbes can cause illness. Most infected persons recover within a week.
-Transmitted through contaminated beverages and food, especially water, milk, meat, and chicken.
-When ingested, they reach the mucosa at the last segment of the small intestine (ileum) near its junction with the colon. They adhere, burrow through the mucus, and are taken into intestinal cells and multiply.
Symptoms include: headache, fever, abdominal pain, and bloody or watery diarrhea.
-The mechanisms of pathology involve a heat-labile enterotoxin called CJT that stimulates secretory diarrhea like cholera.
Diagnosis: Made with fecal samples and occasionally blood samples. Examine the feces with a dark-field microscope, which accentuates the characteristic curved rods and darting mobility.
Treatment: In most instances, rehydration and electrolyte balance therapy. In more serious cases, erythromycin, tetracycline, aminoglycosides, or quinolones.

Ricketsia
-Obligate intracellular parasites
-Gram-negative cell wall
-Among the smallest bacteria
-Nonmotile plemorphic rods or coccobacilli
-Ticks, fleas & louse are involved in their life-cycle
-Bacteria enter endothelial cells & cause necrosis of the vascular lining- vasculitis, vascular leakage & thrombosis
-Treat with tetracycline & chloramphenicol



Four Types of Rickettsiosies
1-Epidemic typhus- carried by lice, starts with a high fever, chills, headache, rash.
2-Endemic typhus- harbored by mice and rats, occurs sporadically in areas with high flea infestation, mild symptoms
3-Rocky mountain spotted fever- carried by dogs and wood ticks, most cases are from the east, spotted rash, can damage heart and CNS
4-Ehrlicha genus contains 2 species of rickettsias; tickborn bacteria cause human monocytic & granulocytic ehrlichiosis

Chlamydia
-Obligate intracellular parasites
-small gram-negative cell wall
-alternate between 2 stages; elementary body- small metabolically inactive, extracellular, infectious form. Reticulate body- grows within host cell vacuoles

Chlamydia trachomatis
-Human reservoir, Two Strains
-Trachoma- attacks the mucous membranes of the eyes, genitourinary tract, and lungs
-Ocular trachoma- severe infection, deforms eyelid and cornea, can cause blindness
-Inclusion conjunctivitis- occurs as babies pass through the birth canal, is prevented by prophylaxis
-STD- urethritis, cervicitis, salpingitis (PID), infertility, scaring
-Lymphogranuloma venereum- disfiguring disease of the external genitalia and pelvic lymphatics



Mycoplasma
Naturally lack cell walls, and are highly plemorphic. They require special lipids from host cell membranes. They are treated with tetracycline and erthyromycin. M. pneumonia- primary atypical pneumonia; pathogen slowly spreads over interior respiratory surfaces causing fever, chest pain, and sore throat. M. hominis and Ureplasma erealyticum- weak sexually transmitted pathogens.

Questions:

Q&A~~Home Page~~Top of Page

1. Why are certain microscopes used instead of staining to see treponema, leptospira and borrelia spirochetes?

2. What is the major side effect of cholera that can lead to death?
a. fever
b. dehydration
c. heart arrhythmia
d. stroke

3. What was the cause of the London cholera outbreak?
a. unsanitary bathing conditions
b. improper disposal of the dead
c. intake of contaminated water from a street pump
d. eating undercooked meat

4. Which blood type is at higher risk for ulcers?
a. A+
b. B-
c. O
d. B+

5. Which of the following is the common cause of food poisoning?
a. Campylobacter jejuni
b. Vibrio cholera
c. Borrelia burgdorferi
d. Leptospira biflexa

6. Humans are the only natural host for this bacteria and is mainly spread through sexual contact.
a. Rickettsia prowazekii
b. Chlamydia trachomatis
c. Leptospira
d. Treponema pallidum

7. A man was admitted into a hospital while vacationing in Brazil. He had a temperature of 103 C, chills, headache, muscle aches, and conjunctivitis. On testing, they found this pathogen in his blood and cerebrospinal fluid.
a. Treptonema pallidum
b. Leptospira
c. Rickettsia prowazekii
d. Chlamydia trachomatis

8. A gumma is:
a. the primary lesion of syphilis
b. a syphilitic tumor
c. the result of congenital syphilis
d. a damaged aorta

9. The treatment choice for syphilis is:
a. tetracycline
b. antiserum
c. penicillin
d. sulfa drugs

10. Lyme disease is caused by _______ and spread by ______.
a. Borrelia recurrentis, lice
b. Borrelia burgdorferi, fleas
c. Borrelia hermsii, ticks
d. Borrelia burgdorferi, ticks

11. Relapsing fever is spread by:
a. lice
b. ticks
c. animal urine
d. a and b

12. The best therapy for cholera is:
a. oral tetracycline
b. oral rehydration therapy
c. antiserum injection
d. oral vaccine

13. Rickettsias and chlamydias are similar in being
a. free of a cell wall
b. the cause of eye infections
c. carried by arthropod vectors
d. obligate intracellular bacteria

14. Which of the following is not an arthropod vector of rickettsioses?
a. mosquito
b. louse
c. tick
d. flea

15. Chlamydiosis caused by C. trachomatis attacks which structure?
a. eye
b. urethra
c. fallopian tubes
d. all of these

16. A breath test is given to people who may have H. pylori. Urea is swallowed and on exhalation, what is given off if H. pylori is present?
a. radioactive O2
b. radioactive CO2
c. ammonium
d. urine

17. How are R. rickettsii and Lyme disease alike?
a. both are transmitted by ticks
b. both are more common on the western seaboard
c. both have a rash that occurs only on the chest
d. none of the above

18. Ship or Prison fever is another name for...
a. Chlamydia
b. Rocky Mountain spotted fever
c. Rickettsia typhi
d. Rickettsia prowazekii

19. Which of the following causes blindness in babies?
a. Campylobacter jejuni
b. Helicobacter pylori
c. Rickettsia prowazekii
d. Chlamydia trachomatis

20. Which of the following has no cell wall or shape?
a. Mycoplasma
b. Chlamydia
c. Rickettsia
d. Campylobacter jejuni



Ch. 21 Comprehension Questions

1. Characteristics of spirochetes
2. What does Treponema pallidum look like?
3. Characteristics of Treponema pallidum
4. What is the primary symptom of syphilis?
5. Where does syphilis’ primary symptom usually occur? What eventually happens to it?
6. What happens during secondary syphilis?
7. If left untreated, what happens after secondary syphilis?
8. What are the symptoms of tertiary syphilis?
9. Characteristics of congenital syphilis
10. Symptoms of congenital syphilis?
11. How is syphilis treated?
12. Famous or literary people with syphilis
13. U.S.’s dark history with syphilis
14. Characteristics of Leptospira
15. What is leptospirosis?
16. How does leptospirosis infection occur?
17. What are the principal targets of leptospirosis?
18. What are the symptoms of leptospirosis?
19. Long-term effects of leptospirosis?
20. Characteristics of Borrelia
21. Characteristics of Borrelia hermsii
22. Symptoms of relapsing fever
23. Why is it called relapsing fever?
24. How is relapsing fever treated and prevented?
25. Characteristics of Borrelia burgdorferi
26. Characteristics of Lyme disease
27. Treatment & prevention of Lyme disease? Vaccine available?
28. When and how was Lyme disease discovered?
29. Characteristics of Vibrio cholera
30. Characteristics of cholera
31. Treatment and prevention of cholera?
32. Vaccine available for cholera?
33. What is one way people in endemic regions prevent becoming infected by the water?
34. Cholera and the beginning of epidemiology
35. Characteristics of Helicobacter pylori
36. What virulence factor of H. pylori can lead to chronic active gastritis? How does this happen?
37. When and who discovered Helicobacter pylori?
38. What kind of person is more likely to develop an ulcer from Helicobacter?
39. How is H. pylori diagnosed?
40. Characteristics of Campylobacter jejuni
41. After C. jenuni is ingested, how does it infect the intestine?
42. Symptoms of C. jejuni?
43. Main virulence factor of C. jejuni?
44. Characteristics of Rickettsia
45. Where on the body is a common target in rickettsial infections?
46. Treatment of Rickettsia?
47. Characteristics of Rickettsia prowazekii
48. Who is Rickettsia prowazekii named after?
49. What are the symptoms of Rickettsia prowazekii?
50. Characteristics of Rickettsia typhi
51. Characterisics of Rickettsia rickettsia
52. Characteristics of Chlamydia
53. Characteristics of Chlamydia trachomatis
54. What are the two strains of Chlamydia trachomatis?
55. Characteristics of ocular trachoma
56. Characteristics of inclusion conjunctivitis
57. Characteristics of sexually transmitted chlamydial diseases

Ch. 21 Comprehension Answers

1. Gram-negative cell wall, periplasmic flagella, flexing and crawling motion, major pathogens are found in genera Treponema, Leptospira, and Borrelia
2. Has 8-20 evenly spaced coils. Very thin, doesn’t stain well, have to use dark-field microscopy to see it. Also can be seen with immunofluorescent staining.
3. Treponema pallidum: 1. Causes syphilis

1. Humans are the natural host – which means we could potentially eliminate it.
2. Extremely fastidious and sensitive, doesn’t survive long outside the host, doesn’t grow well in the lab.
3. Infectious dose is 57 cells, risk of infection from an infected sexual partner is 12-30%
4. Transmitted sexually, also through the placenta
5. Distinct clinical stages: primary, secondary, and tertiary syphilis. Communicable during the first two stages

4. After getting infected, the bacteria incubate from 9 days to 3 months with no symptoms, then a hard, painless chancre (sore) appears at the site of inoculation.
5. Most chancres appear on the internal and external genitalia, but about 20% occur on the lips, nipples, or fingers or around the anus. The chancre heals spontaneously in 3-6 weeks. 6. Secondary syphilis:

1. There is a latency period of 2-8 weeks before this time. Symptoms go away, but the spirochete is very busy invading many systems of the body.
2. The person has a fever and then breaks out in a full-body red or brown rash. Very infectious during this stage because the spirochetes are right on the surface.
3. The rash disappears spontaneously after a few weeks.

7. After resolution of secondary syphilis, the infection becomes latent for up to 20 years. The final stage of syphilis is rare today because of widespread use of antibiotics.
8. Tertiary syphilis symptoms include:

1. painful swollen gummas that develop in the liver, skin, bone, and cartilage;
2. neurosyphilis that can destroy the blood vessels in the brain, cranial nerves, and spinal cord nerves;
3. severe headaches & convulsions;
4. mental derangement;
5. atrophy of the optic nerve & blindness;
6. and the Argyll-Robertson pupil reaction (pupil doesn’t react to light).

9. Congenital syphilis:

1. Treponema pallidum can pass from a pregnant woman’s circulation into the placenta into the fetus.
2. Most common in the 2nd and 3rd trimesters.
3. Inhibits fetal growth and can cause spontaneous miscarriage or stillbirth

10. Infants have nasal discharge, skin eruptions and loss, bond deformation, nervous system abnormalities, and Hutchinson’s teeth (notched, barrel-shaped incisors).
11. Years ago it was treated with mercury, Paul Ehrlich developed Salvarsan for it in 1920 (toxic due to arsenic), now Penicillin G is the best choice. 12. Oscar Wilde’s “The Picture of Dorian Gray” and Charlotte Bronte’s “Jane Eyre” were said to have main characters with syphilis. Winston Churchill’s dad died on it when he was 45.
13. From 1932-1972 the U.S. government did a study on syphilis involving black men – they didn’t know they had the disease and weren’t given treatment for it. Called “Tuskegee Study of Untreated Syphilis in the Negro Male.”
14. Characteristics of Leptospira:

1. Typical spirochetes marked by tight, regular, individual coils with a bend or hook at one or both ends.
2. Its two species are L. biflexa (a harmless, free-living saprobe) and L. interrogans (a zoonotic bacteria that causes leptospirosis in humans and animals)

15. A zoonosis associated with wild animals such as rodents, skunks, raccoons, foxes, and some domesticated animals, particularly horses, dogs, cattle, and pigs. The disease is concentrated mainly in the tropics.
16. Infection occurs …

1. The bacteria is shed in the urine of an infected animal. It can survive for several months in soil or water.
2. Infection occurs almost entirely through contact of skin abrasions or mucous membranes with animal urine or some environmental source containing urine.
3. Not associated with animal bites, inhalation, or human contact. 50-60 cases/year in the U.S.

17. Principal targets are the kidneys, liver, brain, and eyes.
18. Symptoms are a sudden high fever, chills, headache, muscle aches, conjunctivitis, and vomiting. During the second phase, there’s a milder fever, headache due to leptospiral meningitis, and Weil’s syndrome, a cluster of symptoms characterized by kidney invasion, hepatic disease, jaundice, anemia, and neurological disturbances.
19. Causes long-term disability and death from injury to the kidneys and liver – primarily with virulent strains or in elderly patients
20. Characteristics of Borrelia:

1. Comparatively larger spirochete than the others, has 3-10 coils
2. Borrelioses are all transmitted by some type of arthropod vector, usually ticks or lice.
3. The two most important diseases are relapsing fever and Lyme disease.

21. Characteristics of Borrelia hermsii:

1. Causes relapsing fever
2. Carried by ticks, reservoirs are squirrels, chipmunks, and other wild rodents – humans are an accidental host.
3. The spirochetes mature and persist in the salivary glands and intestines of the tick.
4. Epidemics of louse-borne relapsing fever occur whenever famine, war, or natural disasters are coupled with poor hygiene, crowding, and inadequate medical attention (favors lice growth).
5. Louse-borne fever is most common in parts of China, Afghanistan, and Africa.

22. Symptoms of relapsing fever:
a. After a 2-to-15-day incubation period, patients experience an abrupt onset of high fever, shaking chills, headache, and fatigue. b. Grows into nausea, vomiting, muscle aches, and abdominal pain. c. Extensive damage to the liver, spleen, heart, kidneys, and cranial nerves occur in many cases.
23. The fever fluctuates as the spirochete changes and the immune system attempts to control it. Borrelia changes surfaces antigens during growth, so that, in time, the antibodies formed against the earlier antigens lose effectiveness. Cells with the new antigen survive, multiple, and cause a second wave of symptoms.
24. Treated by tetracycline and amoxicillin. Prevented by using insect repellant containing DEET, also controlling rodents and avoiding tick bites.
25. Characteristics of Borrelia burgdorferi:

1. Transmitted by ticks
2. Infected ticks pass through a complex 2-year cycle that involves feeding on mice first as a larva, then feeding on deer as an adult.
3. Causes Lyme disease, which is the most prominent borreliosis in the U.S.

26. Characteristics of Lyme disease:

1. Nonfatal, slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions.
2. 50-70% of cases get a bull’s-eye rash at the site of the tick bite.
3. Early symptoms are fever, headache, stiff neck, and dizziness.
4. If untreated, it can advance to the second stage, where cardiac and neurological symptoms develop, as well as polyarthritis.

27. Treatment is tetracycline and amoxyclline. Prevention by using insect repellant containing DEET, also wearing long pants and long-sleeved shirt while in the woods. A vaccine for dogs is available, human vaccine discontinued.
28. Lyme disease was discovered in the 1970s in Old Lyme, Connecticut, when Polly Murray was beset for years with it and discovered 30 of her neighbors were too. She investigated more after her son was diagnosed with juvenile rheumatoid arthritis and she became skeptical. 29. Characteristics of Vibrio cholerae:

1. Causes cholera
2. Comma-shaped cells with a single polar flagellum
3. Possesses unique O (somatic) antigens and H (flagella) antigens
4. 10-to–the-8th power infectious dose

30. Characteristics of cholera:

1. One of the top seven causes of morbidity and mortality in the world.
2. Warm, monsoon conditions favor outbreaks of cholera.
3. Ingested with food or water; travels through the stomach and infects the surface of the small intestine – noninvasive, does NOT enter cells or deeper tissues.
4. The virulence is due to an enterotoxin called cholera toxin that disrupts the normal physiology of intestinal cells. The toxin causes cells to shed large amounts of electrolytes, accompanied with profuse water loss through secretory diarrhea.
5. Results in watery diarrhea called “rice-water stool”, and dehydration that leads to muscle, circulatory and neurological damage

31. Treatment of cholera is oral rehydration (replace water and electrolytes) and tetracycline. Prevention includes proper sewage disposal and water purification. 32. A vaccine containing live, attenuated vibrios is available for travelers and people living in endemic regions. 33. People in endemic regions will fold a blanket eight times and run their water through it as a filtration system. 34. In 1936, a doctor named John Snow mapped out cases of cholera in London. He traced the cases back to a single water pump called the Broad Street Pump. This was the beginning of epidemiology. 35. Characteristics of Helicobacter pylori:

1. Its primary habitat is the acidic environment of the stomach.
2. Curved cells with a multiple sheathed polar flagella – NOT a spirochete.
3. Causes 90% of stomach and duodenal ulcers.

36. H. pylori produces large amounts of urease, which can neutralize stomach acid. As the immune system attacks the pathogen, certain white blood cells damage the epithelium to some degree, leading to chronic active gastritis. 37. Discovered in 1979 by Dr. J. Robin Warren – he and an assistant swallowed an inoculum and developed a short-term case of gastritis. They were awarded a Nobel Prize in 2005. 38. People with type-O blood have a 1.5-2X higher rate of ulcers – one receptor specific for Helicobacter is the same receptor as type-O blood. 39. H. pylori gives off large amounts of urease and can be initially identified with a test that detects pH changes. Also a urea breath test can also be used – involves swallowing urea that gives off radioactive CO2 in exhaled air if H. pylori is present. 40. Characteristics of Campylobacter jejuni:

1. Considered one of the most important causes of bacterial gastroenteritis (food poisoning) worldwide.
2. Primary pathogen transmitted through contaminated beverages and food, especially water, milk, meat, and chicken.

41. Ingested cells travel to the mucosa at the last segment of the small intestine (ileum) near its junction with the colon. They adhere, burrow through the mucus, and are taken in by the intestinal cells where they multiply. 42. After an incubation period of 1-7 days, symptoms of fever, headache, abdominal pain, and bloody or watery diarrhea develop (i.e. food poisoning).

1. Most people recover within a week.
2. An occasional sequela of this infection is the neurological disease called Guillain-Barre syndrome.

43. C. jejuni produces a heat-labile (if you heat up the food, you’ll kill the toxin) enterotoxin called CJT that stimulates secretory diarrhea like cholera. 44. Characteristics of Rickettsia:

1. All obligate to their host cells and require live cells for cultivation – obligate intracellular parasites (can’t live outside a cell)
2. Gram-negative cell wall
3. Spend part of their life cycle in the bodies of arthropods (ticks, fleas, and lice), which serve as vectors
4. Among the smallest bacteria – not much bigger than a virus
5. Nonmotile pleomorphic rods or coccobacilli (no flagella, no distinct shape)

45. A common target in rickettsial infections is the endothelial lining of the small blood vessels. The bacteria enter and multiply within endothelial cells, causing necrosis of the vascular lining, which leads to vasculitis, vascular leakage, and thrombosis. 46. Treated with tetracycline and chloramphenicol. 47. Characteristics of Rickettsia prowazekii:

1. Humans are the sole hosts of human body lice and the only reservoirs of R. prowazekii.
2. Causes epidemic typhus.

48. Named after Dr. Howard Ricketts and Stanislas von Prowazek, who discovered it in the early 1900s. They investigated it, then both died from it.
49. First symptoms are high fever, chills, headache, muscular pain. Within 7 days, a generalized rash appears. After several years a chronic, recurring form of the disease, known as Brill-Zinsser disease, can appear.

1. First symptoms are high fever, chills, headache, muscular pain. Within 7 days, a generalized rash appears. After several years a chronic, recurring form of the disease, known as Brill-Zinsser disease, can appear.

50. Characteristics of Rickettsia typhi:

1. Causes endemic typhus.
2. Occurs sporadically in areas of high flea infestation.
3. Harbored by mice and rats.
4. Transmission to humans is chiefly through infected rat fleas that inoculate the skin.
5. Anne Frank died of typhus two weeks before the war ended.

51. Rickettsia rickettsii:

1. Causes Rocky Mountain Spotted Fever - the rickettsial disease with greatest impact on people living in North America.
2. Zoonosis carried by dog and wood ticks.
3. Most cases occur in the eastern seaboard states in spring and summer, when the tick vector is most active.
4. Causes a distinct spotted rash over most of the body, can lead to damage of the heart and central nervous system.

52. Characteristics of Chlamydia: a. obligate intracellular parasites b. Small gram-negative cell wall c. Chlamydias alternate between two stages: 1) a metabolically inactive, infectious form called the elementary body that is released by the host cell, and 2) a noninfectious, actively dividing reticulate body that grows within host cell vacuoles. 53. Characteristics of Chlamydia trachomatis: a. Human reservoir b. Two strains – Trachoma strain and Phogranuloma venereum d. Disease is most severe in infants and children. e. Babies can get it while passing through the birth canal. f. The leading cause of blindness worldwide. 54. The two strains of Chlamydia trachomatis: a. Trachoma strain – attacks the mucous membranes of the eyes, genitourinary tract and lungs. Causes ocular trachoma, inclusion conjunctivitis, and the STD. b. Phogranuloma venereum – invades the lymphatic tissues of the genitalia, causes a disfiguring disease of the external genitalia and pelvic lymphatics. 55. Characteristics of ocular trachoma: a. Causes an early, pebble-like inflammation of the conjunctiva and inner eyelid b. Antibiotics taken early on can prevent all complications – especially blindness. c. Caused by Chlamydia trachomatis 56. Characteristics of inclusion conjunctivitis: a. Babies get it while passing through an infected birth canal. b. Routine eye prophylaxis is given to all newborns in the U.S. 57. Characteristics of sexually transmitted chlamydial diseases: a. It’s estimated up to 10% of the population has it. b. About 70% of women are asymptomatic and 10% of men. c. Reportable disease since 1995. d. Chlamydia is the 2nd most prevalent STD. e. A particularly virulent strain result in a severe, disfiguring disease called lymphogranuloma venereum.