spirochaets

Question 1

T/ F ; Spirochaets are culturable

Answer 1

false , they are non - culturable

Question 2

Broadly classify the spirochaetes

Answer 2

family: Brachyspiraceae
genus; Brachyspira

F; Leptospiraceae
G: Leptospira

F: spirochaetaceae
G:Borrelia
G: Treponema

Question 3

Discuss some shared characteristics between 3 medically significant spirochaetes

Answer 3

• Leptospira
• Borrelia
• Treponema

+They are all spirally shaped but the Leptospira is spirally shaped with hooks

+Do not stain with gram stain

+Best visualized by dark field or phase contrast microscope and not visualized by ordinary microscope

+They are all motile

Question 4

Discuss leptospirosis

Answer 4

agent : 2 main species

• Leptospira interrogans ( contains all human pathogens)
• Leptospira biflexa (Non pathogen)

Epidemiology : worldwide

Risk group : farm work enthusiats ,sewer workers and agricultural workers

MOT;

• Zoonotic infection (domestic and wild animals ) although mostly found in rats
• transmitted by either direct contact of infected animal fluid ( exld saliva) or exposure to surface /soil that is contaminated with animal urine

*leptospira colonise the renal tubule of natural host and excreted in urine and penetrates skin or mucous membrane

human to human transmission is rare

Pattern of disease : disease can range from sub clinical to systemic disease
‘Phases of disease
+1. Early infection ( systemic dissemination )
+late infection (target organ damage

• Organs affected
• eyes ,meningitis ,heart ,kidney and hall mark of weil s disease is liver dysfunction ,renal failure and haemorrhagic manifestation

Question 5

Discuss Lyme s disease

Answer 5

agent : Borrelia burgdorferi (disease is USA)
Borrelia afzelii
Borrelia garinii
Disease in Europe all 3

Epidemiology : N America ,Europe and no cases in SA

Risk group : farmers , animal works ,recreational and occupational exposure

MOT:
*Zoonotic infection (dog, farm animals and wild animals )

• transmitted by arthropods vectors eg hard bodied ticks(ixodes scapularies)
• Borrelia are inoculated at the site where meal is taken

pattern of disease : 
*3 stages of disease 
\+Early infection localized 
2.Early infection disseminated 
3.Late /Persistent or chronic infection 

Organ affected : Joints ,cranial nerves ,skin , heart

Question 6

Name the disease entities caused by the different subspecies of Treponema pallidum

Answer 6

1. Non-venereal syphilis (Non sexually transmitted )
   * Yaws : Treponema pallidum sub spp pertnue
   * Endemic syphillis (Bejel ); T.pallidum subspp endemicum
   * Pinta : T pallidum subspp carateum
2. Venereal syphilis ( sexually transmitted )
   * T.pallidum spp subspp a ccause genital ulcer disease
   * the ulcer painless

Epidemiology : Found world wide

Question 7

Organs commonly affected by T.pallidum subspp pallidum

Answer 7

Brain, Mucous ,heart ,skin ,genital areas

Question 8

Compare and contrast non sexually transmitted treponematoes

Answer 8

Similarities :
MOT ;
* Direct contact with lesions

+Organs affected
:Can spread to other areas of the body by hematogenous route
-skin

difference :
Yaws :world wide
Bejel : dry ,arid at=reas ,N Africa ,S Asia ,Mediterranean
Pinta : S America and the Caribbean