Causative agent 
- Leptospira interrogans (some 200 serovars)


Differential diagnosis 
- Brucellosis
- Porcine parvovirus infection
- Aujeszky's disease
- Swine fever
- SMEDI virus


1. History taking 
- History of onset of the disease (endemic disease)
- Oftenly occurs during rainy season
- Contamination of animal house and the feed by
  urine of reservoirs especially rodents
- Oftenly onset in young animals
- Onset of abortion in sow


2. Clinical examination 
- Usually subclinical infection
- Fever (40°C), dull, anorexia, diarrhea, icterus with
  hemoglobinurea in acute or subacute infection
- Abortion, stillbirth and neonatal mortality
  accompanied by fever, loss of milk and jaundice in
  the sow


3. Serological tests 
- Microscopic agglutination test (MAT)
- Antigen: 24 serovars: Bratislava, Autumnalis,
  Ballurn, Bataviae, Canicola, Celledoni, Cynopteri,
  Djasiman, Grippotyphosa, Hebdomadis,
  Icterohaemorrhagiae, Javanica, Louisiana, Manhao,
  Mini, Panama, Pomona, Pyrogenes, Ranarum, Sarmin,
  Sejroe, Shermani, Tarassovi, Patoc
- Test sera : diluted at 1:50


4. Microscopic examination 
- Microscopic darkfield examination : body fluid,
  urine, blood or contaminated water

5. Bacterial isolation 
Specimen     : kidney, liver, urine, aborted piglet etc.
Medium        : liquid EMJH
Examination : organisms are thin, tightly coiled
                       spirochetes with one or both ends
                       hooked by darkfield microscopy


6. Necropsy 
- Jaundice in all the tissue
- Kidney : dark, small hemorrhages and edema
  around the kidneys
- Liver : enlarged and dark
- Bladder : red or port wine-coloured urine
- Aborted piglet : pinhead, necrotic foci in the liver,
  yellow peritoneal and pleural fluid


7. Histopathological observation 
- Piglet : interstitial nephritis with shrunken kidneys
  showing small bands of fibrous tissue extending
  into the kidney substance
- Pig : greyish white area in the cortex of the
  kidney, the affected renal tubules are surrounded
  by dense masses of leukocytes (mostly
  lymphocytes and plasma cell). The specific staining
  of leptospira is demonstrated by Warthin Starry
  method


8. Experimental animal inoculation 
- Guinea pigs, hamster, mice (intraperitoneal
  injection)
- Leptospira are visible by darkfield microspy in the
  peritoneal fluid 3-5 day after injection


Control 
- Elimination of carriers
- Prevention of transmission
- Immunization
- Chemotherapy