Symptoms of leptospirosis appear between 4 days and 2 to 3 weeks after contact with the infection. Most often they look like a flu with:

– fever (generally above 39 ° C),

– chills,

– headaches,

– muscle, joint, abdominal pain.

– bleeding can also occur.

In the most serious forms, it can appear, in the following days:

– jaundice characterized by a yellow coloration of the skin and the whites of the eyes,

– kidney failure,

– liver failure,

– pulmonary damage,

– a brain infection (meningitis),

– neurological disorders (convulsions, coma).

Unlike the severe forms, there are also forms of infection without any symptoms.

If the recovery is long, there are usually no sequelae apart from the possibility of late eye complications. However, in severe forms, untreated or treated with delay, mortality exceeds 10%.

In all cases, the diagnosis is based on clinical symptoms and signs, blood tests, or even the isolation of the bacteria in certain samples.

At the very onset of infection, only detection of DNA, i.e. genetic material of the bacteria in the blood or other body fluids, can make a diagnosis. The search for antibodies against leptospirosis remains the most used test, but this test is only positive after a week, the time that the body makes antibodies against this bacteria and that they can be in quantity. sufficient to be dosable. It may therefore be necessary to repeat this test if it is negative because it was carried out too early. In addition, the formal confirmation of the infection must be made by a special technique (microagglutination test or MAT) which, in France, is only carried out by the national reference center for leptospirosis.