Mycoplasma, Spirochetes, Chlamydia, and Rickettsia II Flashcards
Relapsing fever often described as epidemicor endemic
Borrelia recurrentis
Organism released only after crushing the lice; not transmitted in saliva, excrement or transovarially
Borrelia recurrentis
Transmitted by bites from infected ticks(different than those causing Lyme disease); infected ticks are healthy and transmit transovarially
Endemic relapsing fever (Borrelia recurrentis)
Serve as a reservoir for borella recurrentis
Rodents and small animals
Occurs in certain arthropod vectors as they transmit disease-causing pathogens from parent arthropod to offspring arthropod
Transovarial transmission
Sudden onset of fever with chills, severe headache and malaise lasting 3-6 days and ending abruptly
Relapsing fever
The relapse in relapsing fever occurs
7-10 days later
The severity of symptoms and duration of illness progressively decrease with each
Relapse
Usually associated with a single relapse
Louse-borne relapsing fever
Primarily a disease of wild and domestic animals, human infection through direct or indirect contact with animals
Leptospira
What is the source of infection with leptospira in descending order?
Dogs, livestock, rodents
Chronic renal infection in animals may be asymptomatic leading to continuous shedding of the organism in the urine
Leptospira
Human infection usually indirect, from ingestion of contaminated water or food, or swimming or bathing in contaminated water
Leptospira
Leptospira are viable in water for
Several weeks
Likely very under-reported; may be a prominent zoonosis, especially in tropical regions
Leptospira
Both primary and secondary lesions rich in spirochetes and highly infectious
Treponema pallidium
Most often transmitted by sexual intercourse, but can be transmitted through the placenta or during birth, by kissing, by transfusion of fresh human blood, other sexual contact or by accidental direct inoculation
Treponema pallidum
Can invade virtually any organ in the body and the CNS
Treponema pallidum
Can have active lesions on fingers, breasts, lips, oral cavity or genitals
People infected with syphilis
Heals spontaneously. 30% of infected are completely cured without treatment
Primary stage of syphilus
The secondary stage of syphilis is the disseminated stage where we can see secondary lesions
Anywhere on the body
Serologic tests positive, but no clinical manifestations; 30% stay at this stage if untreated, however blood remains infectious
Latent stage of syphilis
Slow progressing and we can see inflammatory disease affecting any organ in the body
Late (tertiary) stage of syphilis
Symptoms range from subacute meningitis to mental deterioration
Neurosyphilis
Cardiovascular syphilis leads to necrosis of the
Aorta
Lesions in skin (painless) and bone (deep, gnawing pain)
Gummatous syphilis
May result in fetal death and resulting miscarriage, or stillborn at term; signs of congenital syphilis may appear in childhood as developmental abnormalities
Congenital syphilis
What are some of the signs of congenital syphilus?
Notched teeth, saber shins, and saddle nose
Because live bacteria are present in primary and secondary syphilis–ANY physical contact-either sexual, or nonsexual, can
Spread the infection
Can be quickly and directly detected upon examination of exudate from primary, secondary and congenital lesions by dark-field microscopy
T. pallidum
Measure either nonspecific nontreponemal or specific antitreponemal antibodies
Serological tests for T. pallidum
Rely on the fortuitous observation that Ab’s to a lipoidal antigen present in a wide array of host tissues are specifically generated upon syphilis infection
Nontreponemal Tests
These antibodies are referred to as
Reagin
Utilize cardiolipin extracted from mammalian tissue (e.g. beef heart) as the Ag
Nontreponemal Tests
Then addition of lecithin and cholesterol sensitizes the cardiolipin to react with syphilitic reagin, resulting in
Flocculation
What are the two types of tests to measure the presence of reagin?
Flocculation tests and Complement fixation
Reagin in serum can fix complement in the presence of
Cardiolipin
Unfortunately though, generation of reagin antibodies occur in
Other infections
Patients with progressive tertiary syphilis may spontaneously become negative using
Nontreponemal tests
Detect T. pallidum antibodies in patient serum
Specific treponemal tests