Treponema pallidum, borrelia and leptospira interrogans Flashcards
Give the four subspecies of Treponema pallidum
Treponema pallidum
Treponema pertenue
Treponema endemicum
Treponema carateum
What disease does Treponema pallidum cause?
Syphilis (worldwide)
What disease does Treponema pertenue cause?
Yaws
What disease does Treponema endemicum cause?
Endemic syphilis (Middle East and Central and South Africa)
What disease does Treponema carateum cause?
Pinta
What is the shape of Treponema spp?
Helically coiled, corkscrew shaped cells with 8-12 regular spirals
Are Treponema encapsulated?
No
Is Treponema motile?
Yes
Can Treponema form spores?
No
What can Treponema form instead of spores in the body
Cysts
How are Treponema different from other motile bacteria?
Endoflagella
Is Treponema gram positive or neegative?
It is gram negative
Is Treponema pallidum aerobic or anaerobic
Strict anaerobe
What staining method can be used to reveal Treponema from smears?
Silver impregnation methods
How can live Treponema be visualised?
Dark field microscopy
How difficult is it to culture Treponema pallidum?
It is fastidious, requiring very narrow pH and temperature ranges. It has not been successfully cultured in vitro
Describe the resistance of Treponema pallidum
It can not survive a long time in the environment. It is rapidly inactivated by mild heat, cold,
desiccation, and most disinfectants.
It is inactivated by contact with oxygen, distilled water, soap
T.pallidum is sensitive to arsenicals, mercurials, bismuth, common antiseptic agents and
antibiotics (penicillines).
How is Treponema pallidum transmitted?
Through sexual contact (venereal disease);
Through placenta (congenital syphilis);
Rarely with direct contact and with infected blood during transfusion
How long is the incubation period for syphilis?
Incubation period is about a month (10 - 90 days)
Give 4 stages in the clinical manifestation of infection with Treponema Pallidum
Primary syphilis
Secondary syphilis
Latent syphilis
Tertiary syphilis
How does primary syphilis begin?
The organisms penetrate mucous membranes or enter through the very tiny cuts on the skin.
Treponema multiplies in the site of entry causing formation of the primary specific lesion, named
“hard chancre”.
Describe the chancre of primary syphilis
Chancre is painless, circumscribed, indurated, superficially ulcerated lesion
What is the next stage of primary syphilis after formation of a chancre?
Treponema disseminates away from the site of initial entry to regional lymph nodes and
provokes their specific inflammation (syphilitic buboes).
Describe the changes in regional lymph nodes in primary syphilis
Lymph nodes are swollen, discrete,
indurated, and rubbery.
What is the normal progression of a chancre over time in primary syphilis?
The chancre heals spontaneously (!) in 10-40 days, leaving a thin scar
Roughly how long does primary syphilis last?
3 months
When does secondary syphilis set in?
3 months after primary syphilis
What causes the secondary lesions in syphilis?
The secondary lesions are due to dissemination through
the blood and wide-spread multiplication of the spirochetes.
How may secondary syphilis present?
It may appear with: ROSEOLAR RASHES PAPULAR RASHES MUCOUS PATCHES (broad, flat, erosive lesion of secondary syphilis that occurs on moist skin or mucous membranes and is often marked by a yellowish discharge) CONDYLOMATA (anogenital warts).
In which stage of syphilis are patients most infective?
The secondary stage as the spirochetes are present abundantly in the lesions
What is the natural progression of secondary syphilis?
Lasts 2-3 years
Lesions heal
spontaneously (!) but during first 4-5 years there may be relapses of rashes
How is latent syphilis diagnosed?
Serological tests
When does tertiary syphilis present?
Years to decades after secondary syphilis
How does tertiary syphilis present?
After several years tertiary syphilis
appears with cardiovascular lesions (aneurysms), chronic gummata and neurological
manifestation (tabes dorsalis or dementia)
What are gummas?
Highly destructive lesions (necrotizing granulomas ) that usually occur in skin and
bones but may also occur in other tissues. Gumma includes few treponemes
How well does the immune system deal with Treponema pallidum?
Immunity is weak, non-sterile, and cell-mediated. Antibodies which are formed during infection
are not protective
What is the significance of the antibodies produced during infection by Treponema pallidum?
Diagnostic significance
Can a person be reinfected with Treponema pallidum?
Yes (superinfection)
What is different about getting infected by Treponema pallidum a second time?
Due to ‘chancre immunity’ there are no primary signs
What is the usual therapy of syphilis?
Prolonged penicillin preparations
How can syphilis be diagnosed in a lab during the primary and secondary stages?
Microscopy with dark field microscopy of native smears or fluorescent antibody (immunofluorescence) test
Can syphilis be diagnosed using serology?
Yes, 2-3 weeks after chancre appearance
What group of borrelia species cause Lyme’s disease?
B.burgdorferi
How can the size of Borrelia be described?
Large
Are Borrelia motile?
Yes
Describe the shape of Borrelia
3-8 wide, open coils
Are Borrelia gram positive or negative?
Negative
Are Borrelia aerobes or anaerobes?
Microaerobic - need oxygen but in lower concentration than atmosphere
Can Borrelia be cultivateed?
Not into media but possible in chicken embryo or in rodents
What diseases are Borrelia species primarily responsible for?
Relapsing fevers and Lyme’s disease
How is Borrelia transmitted to humans?
Lice or ticks
What species of Borrelia is responsible for the louse-borne/epidemic type of relapsing fever?
Borrelia recurrentis
What is the reservoir host for Borrelia recurrentis?
Humans
What is the reservoir for Borrelia species which cause the tick borne/endemic type of fever?
Rodents
What is the vector for Borrelia bungdorferi?
Ticks
What are the main reservoirs for Borrelia bungdorferi?
Rodents and deer
What does Borrelia responsible for relapsing fever do once it has entered the body?
Enters the bloodstream and multiplies in the organs
What is the body’s response to the presence of Borrelia recurrentis?
Mounting an immune response including a fever, lasting 3-5 days which destroys the bacteria in the blood
Why does the fever relapse after an immune response destroys Borrelia recurrentis in the blood?
The pathogen has he ability to undergo multiple cyclic antigen variations so that once one strain is eliminated, another comes to dominate and infect the blood, triggering another immune response with new antibodies.
How long is the afibrile period usually in relapsing fever?
4-10 days
How can Borrelia recurrentis be diagnosed in a lab?
Microscopy of stained blood smears
How can epidemic and endemic Borrelia strains be distinguished?
Injection into guinea pigs which are highly sensitive to animal Borrelia and less sensitive to human Borrelia
What is the incubation period for Lyme’s disease?
3-30 days
What are the 3 stages of Lyme’s disease?
- Localised infection
- Disseminated infection
- Persistent infection
What happens during the localised infection stage of Lyme’s disease?
There appears an expanding annular skin lesion (erythema migrans).
What happens during the disseminated infection stage of Lyme’s disease?
Fever
Myalgia
Arthralgia
Lymphadenopathy.
When do the symptoms of the persistent infection stage of Lyme’s disease arise?
Arises in months or years after the disseminated stage
What happens during the localised infection stage of Lyme’s disease?
Chronic arthritis
Polyneuropathy
Acrodermatitis
Encephalopathy
How can laboratory diagnosis of Borrelia burgdorferi be done?
Serology
Microscopy in the site of entry during the first stage
What are the prophylactic methods that should be used to avoid Borrelia infections?
Avoid the vectors
Cover skin with clothing in tick habitats
Use tick repellent in tick habitats
Periodic skin inspection and tick removal
Avoid endemic areas
What is the treatment for Borrelia?
Borrelia are sensitive to penicillins, tetracyclines, newer macrolides and cephalosporins.
Describe the shape of Leptospira interrogans
Slender
Tightly coiled
Flexible
Hooked ends that create an S or C shape
Is Leptospira interrogans encapsulated?
No
Is Leptospira interrogans motile?
Yes
Is Leptospira interrogans spore forming?
No
Is Leptospira interrogans Gram positive or negative?
Negative
How can Leptospira interrogans be visualised?
Dark field microscopy
Visualisation in tissue by silver impregnation methods
Can Leptospira interrogans be easily cultured?
Yes they are far from fastidious
Is Leptospira interrogans sensitive to heat?
Yes
Is Leptospira interrogans sensitive to acid?
Yes, killed by stomach acid in 30mins
Is it easy to kill Leptospira interrogans with disinfectants?
Yes
How is the survivability of Leptospira interrogans in water?
L.interrogans can survive into clean water for some days and can multiply in the environmental water at summer.
How long can soil remain infective if it is contaminated with urine containing Leptospira interrogans
Urine-contaminated soil can remain infective for as long as 14 days.
What are the main reservoirs of Leptospira interrogans?
Rodents
Domestic animals
A range of hosts worldwide
How is Leptospira interrogans transmitted?
Direct or indirect contact with urine containing virulent leptospires.
Leptospires from urine-contaminated environments, such as water and soil, enter the host through the mucous membranes and through small breaks in the skin.
How long is the incubation period of Leptospira interrogans?
About 10 days (3-25)
Where does Leptospira interrogans go after entering the body?
Through the blood it reaches the organs, most commonly the CNS, kidneys and liver
What are the symptoms during onset of infection with Leptospira interrogans?
Abrupt fever Severe headache Muscle pain Nausea Jaundice in severe cases
How long does the initial phase of leptospira interrogans infection last?
7 days
What takes place after the initial phase of infection by Leptospira interrogans?
Leptospires are rapidly eliminated from all host tissues except the brain, eyes, and kidneys.
What is the most notable feature of severe leptospirosis?
Progressive impairment of hepatic and
renal function
How is the immunity after leptospirosis?
It is primarily humoral (antibody - mediated)
Type-specific
Long-lasting (may persist for years).
Cell-mediated immunity is not protective.
Due to a lot of serotypes immunity in general is weak
Can microscopy be used to diagnose leptospirosis?
Yes
Where can samples be taken from for microscopy of Leptospirosis interrogans?
Blood (first 8-10 days)
Urine (from second week)
CSF
Is culture used to diagnose leptospirosis?
No, too slow
is serology used to diagnose leptospirosis?
Yes
