1. Objectives By the end of this lecture the student must be:
A) Identify the genus Spirochetes & Borrelia
B) describe the chemical tests for this genus
C) Differentiate between different sps.
D) List and match the symptoms, diagnosis and treatment for different sps.

2. General characteristics Spirochetes
Tiny (0.2 W x 6-20 m L), thin walled, flexible, spirals (helical) that like corkscrew
They are coiled into regular helices (6-14/cell)
Move in a unique spinning fashion via 6 thin endoflagella called axial filaments
Flagella lie between outer membrane & PDG layer
Gram negative
Too small to be seen using the light microscope

3. Special procedures are required to view spirochetes
Dark field microscopy
Immunofluorescence
Silver stain (Fontana’s silver or Giemsa’s stain)
Pathogenic species do not grow on artificial media
While non-pathogenic species can be grow
Can be propagate some strains of spirochetes by inoculating it into the testes of the living rabbit

4. Classification of Spirochetes
Human pathogens belong to following 3 genera:
Treponema
Leptospira
Borrelia
Others (saprophytes) are found in water, sewage & in mouth & genital tracts of humans

5. Treponema pallidium The causative agent for STD “syphilis”
Syphilis is either
Acquired (STD, Venereal)
Transmitted from infected skin or mucous membrane (genitalia, mouth, rectum) to other person by intimate contact
Congenital
Transmitted from pregnant women to their fetus
Blood transfusion
Rarely reported
Men are more susceptible to contract syphilis than women
Marked increase in syphilus in homosexual men

6. Stages of venereal syphilis
Primary syphilis
Primary lesion is Hard chancre
Develop on genitals in day
Chancre heals spontaneously in 3-12 week without scar
Enlargement of lymph nodes on genital organs
Firm, painless, indurated & ulcerated lesion; covered with a thick exudate rich in spirochetes
Highly infectious
Spirochetes spread widely in tissue leading to 2ry syphilis

7. Stages of venereal syphilis
Secondary syphilis
Most infectious stage
Untreated patient enters bacteremic or 2ry syphilis
1-3 months later, secondary lesions may appear
T. pallidium multiply and spread via blood
This stage is systematic and characterized by
Generalized lymphadenopathy
Maculopapular skin rashes on the body & condylom latum (wart) at mucocutaneous junctions
Lesions heal spontaneously over 6 week and yet the disease may progress latency & then to tertiary stage

8. Stages of venereal syphilis
Latent Syphilis
Most patients are asymptomatic during this period
Early latent period
Last for 1-2 years after the 2nd stage
25% of patient develop symptoms of 2ry syphilis
Patient can infect other
Late latent period
Last for many years
No symptoms occur and patients are not infectious
30% of untreated patients slowly progress to 3ry syphilis
The rest will remain asymptomatic

9. Stages of venereal syphilis
Tertiary syphilis
Develops over 6-40 year with slow inflammatory damage to organs, blood vessels & nerve cells
It can be grouped into 3 general categories
Gummatous syphilis
Occurs 10 year after 1ry stage in 10% of untreated
May show localized granulomatous lesions (gumma) which eventually necrosis and become fibrotic
Noninfection lesion are found mainly in skin & bones

10. Stages of venereal syphilis
Cardiovascular syphilis
3-10 year after 1ry stage in 15% of untreated patients
Characterized by aortic aneurysm & necrosis in aorta
Neurosyphilis (Late tertiary or quaternary syphilis)
Occurs year  in 8% of untreated patients
Asymptomatic neurosyphilis, subacute meningitis, brain infarction, mental deteriorations & psychiatric symptoms
In 3ry lesion , T. pallidium are rarely seen

11. Congenital syphilis
Transplacental spread of T. pallidium after the 1st trimester of pregnancy may result in
Fetal death
Prematurity or
Congenital syphilis
The early syndrome may not present at birth, only developing during the subsequent 4 weeks
They are characterized by
Generalized rash resemble 2nd acquired syphilis
Enlargement of the liver, spleen and lymph nodes
Congenital syphilis leaves residual characteristic sign
Hutchinson’s teeth
Saddle nose or nose deformity

12. Immunity of syphilis Immunity of T. pallidium is incomplete
Antibodies do not stop the progression of the disease
Treated syphilitic Patient can contract syphilis again
Late syphilitic patient is relatively resistant to reinfection
The antigens of T. pallidium induce
Specific antibodies (non-treopenemal); detected by immuno-fluorescence or hemagglutination tests
Nonspecific antibodies (reagin): detected by the flocculation of cardiolipin extracted from beef heart tissues
Both specific and non-specific antitreponemal antibodies are used in serological diagnosis of syphilis

13. Diagnosis of Syphilis Syphilis is confirmed by
Finding T. pallidium in exudates from the lesions
Or by detection of antibodies in the serum
During t 1ry and 2ry stages spirochetes are demonstrated in the early lesions in wet preparation by dark field or immunfluorescense microscopy
Stained with either Fontana or Giemsa stain
Not seen on a Gram-stained smear
During 2ry & 3ry syphilis can be detected serologically

14. Serological Tests of Syphilis
Patients develop 3 types of antibodies
1st is known as a lipoidophil antibody called regain
Tests depend on the detection of regain
Non-specific test/Standard Tests for Syphilis (STS)
STS used for routine screening
STS involves use of non-treponemal antigens (Cardiolipin) which react with regain in patient’s serum
Can be demonstrated by CFT (Wassermann test) or by Flocculation Tests such as Venereal Disease Research Laboratory (VDRL) or Rapid Plasma Regain (RPR) test

15. Serological Tests of Syphilis
2nd antibody called Reiter which react with a protein component found in non-pathogenic T. reiter
This test called Group specific test
Demonstrated by Reiter Protein CFT
This test is more specific than the STS but gives fewer false positive results

16. Serological Tests of Syphilis
3rd type of antibody reacts directly with T. pallidium
These tests are specific
Using Nichol’s strain
It can be demonstrated by T. pallidium Immobilization (TPI) test, Fluorescent Treponemal Antibody (FTA) test and T. pallidium Haemagglutination (TPHA) test
This test is the most specific tests

17. Prevention, Control & Treatment
There is no vaccine against syphilis
This disease is controlled by
Early diagnosis and appropriate treatment
Use of condoms
Follow-up of infected individuals & their contacts
This disease is treated by Penicillin
Tetracycline or Erythromycin can be used in allergic patients to Penicillin

18. Non-venereal Treponema
There are three subspecies of T. pallidium
T. pallidium subspecies endemicum
It causes endemic syphilis (Bejel)
T. pallidium subspecies pertenue
It causes yaws
T. pallidium subspecies carateum
It causes pinta

19. Borrelia causing diseases
Borellia
Causing
Relapsing Fever
Endemic (European)
Longer febrile period
Fewer relapses
B. recurrentis
Transmitted by Lice
Endemic (Africa)
Shorter febrile period
More relapses
B. duttoni
Transmitted by Ticks
Lyme
B. burgdorferei

20. Main differences between the two types of relapsing fever
European or louse-borne type
West African or Tick-borne type
Caused by B. recurrentis
B. duttoni
Transmitted by body louse
Tick
Often appears in epidemics
Endemic
Long febrile period and fewer relapses
Shorter febrile and more relapses
Spirochetes not transmitted to louse progeny
Transmitted to tick progeny