Changes

*Serovars are fairly host-specific, causing mild disease in the maintenance host, with shedding in the urine

*Serovars are fairly host-specific, causing mild disease in the maintenance host, with shedding in the urine

*Maintenance hosts may transmit the infection to incidental hosts, which are less susceptible to infection, but develop serious disease

*Maintenance hosts may transmit the infection to incidental hosts, which are less susceptible to infection, but develop serious disease

*Pathogenesis and pathogenicity

*Pathogenesis and pathogenicity

**Depends on virulence of the serovar and susceptibility of the host

**Depends on virulence of the serovar and susceptibility of the host

**Leptospires invade tissues through moist skin or via mucous membranes, aided by their motility

**Leptospires invade tissues through moist skin or via mucous membranes, aided by their motility

**Leptospires may invade via receptor-mediatied endocytosis

**Leptospires may invade via receptor-mediated endocytosis

**They disseminate through the body via the blood stream

**They disseminate through the body via the blood stream

**Antibodies clear organisms from the blood stream after about 10 days of infection

**Antibodies clear organisms from the blood stream after about 10 days of infection

**Organisms may persist in the renal tubules, uterus, eye or meninges

**Organisms may persist in the renal tubules, uterus, eye or meninges

**Evade phagocytosis possibly via macrophage apoptosis

**Evade phagocytosis possibly via macrophage apoptosis

**Damage red blood cell membranes and endothelial and liver cells, leading to haemolytic anaemia, jaundice, haemoglobinuria and haemorrhage in acute leptospirosis

**Damage red blood cell membranes and endothelial and liver cells, leading to haemolytic anaemia, jaundice, [[General Pathology - Pigmentation and Calcification#Haemoglobin|haemoglobin pigmentation]], haemoglobinuria and haemorrhage in acute leptospirosis

*Diagnosis

*Diagnosis

***The host-adapted serovar ''canicolar'' causes acute renal failure in puppies; a chronic uraemic syndrome may follow

***The host-adapted serovar ''canicolar'' causes acute renal failure in puppies; a chronic uraemic syndrome may follow

***Incidental infections with serovar ''icterohaemorrhagica'' or ''copenhagenii'' cause renal failure

***Incidental infections with serovar ''icterohaemorrhagica'' or ''copenhagenii'' cause renal failure

***Serovar ''bratislava'' causes abortion and infertility in dogs, which may be the maintenance host

***Serovar ''bratislava'' causes abortion and infertility in dogs, which may be the maintenance host

***Infections uncommon in cats

***Infections uncommon in cats