Leptospirosis Flashcards
1
Q
Why is Leptospira so important?
A
- 0.5 million cases in humans a year
- zoonotic
- economic impacts in production
- 25% human mortality
- dogs - kidney failure
- rats carry it
2
Q
What is the highest risk factor for humans?
A
- water sports
- rat bite
3
Q
What is Leptospira?
A
- G-ve
- aerobic
- helically coiled
- flexous
- slender
- motile
- 0.1-8um
- can fit through filters and stays in glass cracks
4
Q
Whats its order?
A
- Spirochaetales
5
Q
Whats its family?
A
- leptispiracaea
6
Q
What are the characteristics of leptospira?
A
- outer sheath
- multi layered membrane (surrounds periplasmic flagella)
7
Q
Describe the classification?
A
- L.biflexa - non pathogenic
- L. interrogans - pathogenic
- e.g. L. interogans canicola
- 250 pathogenic serovars
- 25 serogroups
8
Q
How do you culture Leptospira?
A
- Korthof broth
- Stuarts broth
- Fletchers semi-solid medium
- EMJH
- 30 degrees, 8 weeks, anaerobically
9
Q
Describe the pathogenesis of Leptospira
A
- gains access to body through mucous membranes/ gut
- causes vascular damage
- DIC - disseminated intravascular coagulation
- damage vascular endothelium - haemorrhages
- liposacchide
- flagella
- haemolysin
- cytotoxic protein
10
Q
Describe the immunity and persistence
A
- antibody production - a few days after onset
- maternal antibodies - short lived
- activity greatest where few antibodies:
- eyes
- urethra
- tubules
11
Q
How do you diagnose Leptospira?
A
- phenotypic test developed by Martin and Pettit - 1918
- agglutination-lysis test (RAL)
- developed - MAT ( microagglutination test)
12
Q
What samples are needed for diagnosis?
A
- mid stream urine
- liver tissue
- kidney tissue
- foetal tissue - abomasal contents, cotyledons, uterine discharge
- blood
13
Q
What are the different methods for diagnosis?
A
- clinical signs
- MAT - test for antibodies in blood
- FAT - fluorescent antibody test
- dark field microscopy
- culture
- PCR
- ELISA
- PM (gross and histo)
14
Q
Which animals are reservoirs?
A
- all mammals - in kidneys
- rodents, cattle, buffalo, sheep, goats, pigs and horses common
15
Q
Rodents and leptospira?
A
- shed throughout lives with no clinical signs
- primary source of infection to humans
- associated serovars = icterohaemorrhagica, copenhageni, grippotyphosa, ballum
16
Q
How does transmission occur in humans?
A
- through tissues, urine, secretions and contaminated water of infected animals
- through damaged skin/ intact mucosa/ eyes