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 |
Specialty: Infectious Diseases
