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Description

The diagnosis of leptospirosis can be made in sick animals by using a checklist covering both clinical and laboratory features. Contact with an affected animal can identify humans with possible leptospirosis. This was developed by the World Health Organization (WHO).


 

Clinical Features

Clinical Feature

Finding

Points

fever

yes

2

 

no

0

malaise, weakness, listlessness, depression

yes

1

 

no

0

convulsions

yes

1

 

no

0

conjunctivitis

yes

2

 

no

0

anemia

yes

2

 

no

0

hemorrhages

yes

5

 

no

0

hemoglobinuria

yes

10

 

no

0

jaundice

yes

5

 

no

0

abortion/stillbirth or jaundiced/hemorrhagic newborn

yes

20

 

no

0

mastitis with discolored milk (in cattle)

yes

10

 

no

0

 

Laboratory Features

 

Culture:

• isolation of leptospira on culture allows for definitive diagnosis.

 

Serologic Testing

Vaccination Status

Finding

Points

single high titer

unvaccinated

yes

10

 

 

no

0

 

vaccinated

yes

5

 

 

no

0

rising titers with paired samples

unvaccinated

yes

30

 

 

no

0

 

vaccinated

yes

20

 

 

no

0

 

likelihood score =

= SUM(points for clinical features) + SUM(points for laboratory features)

 

Interpretation:

• minimum likelihood score: 0

• maximum likelihood score: 88

• Isolation of leptospira on culture allows definitive diagnosis.

• With negative cultures the higher the likelihood score the greater the probability of leptospirosis.

 

Likelihood Score

Diagnosis of Leptospirosis

<= 20

unlikely

21 – 29

possible

>= 30

presumptive

 


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