Leptospira
Leptospira
Morphology
- Spirochete Leptospira interrogans
- Corkscrew-shaped bacteria, which differ from other spirochaetes by the presence of end hooks.
- Are mobile
- Aerobic
Host
- Zoonoses
- Leptospira affects wild and domestic animals worldwide.
- Man is an accidental host.
- Rats and small rodents are the main reservoirs of Leptospira.
Media used for isolation
- Ellinghausen – Mecullough – Johnson Harris (EMJH) medium
- Fletcher medium
- Korthof medium
- Stuart’s medium.
Modes of transmission
1. Direct contact
- Transmission of leptospires may follow direct contact with urine, blood or tissue from an infected animal.
2.Indirect contact
- Indirect contact of broken skin with soil, water or vegetation contaminated by urine of infected animals or through ingestion of food or water contaminated with leptospirae.
3. Droplet infection
- Through inhalation by breathing air polluted with droplets of infected urine.
- Direct man to man infection is rare.
High risk groups are:
- Farm worker
- Sewage worker
- Workers in fishing indusrties
- Slaughterhouse employees
- Veterinarians
- Coal miners
Clinical features
- Incubation period of Leptospirosis is 1-2 weeks.
- Vasculitis is responsible for the most important manifestations of the disease, mainly affect the kidney and liver.
Leptospirosis may present as one of the two clinical types:
(1) Anicteric form
- It is mild form and accounts for 90% of cases of leptospirosis.
- It presents as acute influenza like illness, with fever, chills, headache, myalgia, vomiting, sore throat and pulmonary involvement like cough, hemoptysis and chest pain.
(2) Icteric form
- It is severe form and accounts for 5-10% of cases of leptospirosis.
- It is also called icterohemorrhagic fever or hepto-renal syndrome/Weils’ disease because of following manifestations:
- Hemorrhagic manifestations: Epistaxis, petechice, purpura, ecchymoses
- Hepatic manifestations: Jaundice (often profound), heptaomegaly
- Renal manifestations: ATN, anuria or oliguira, T BUN & creatinine.
Diagnosis of leptospirosis
1. Microscopic Demonstration
- Dark-field microscopy or by immunofluorescence or light microscopy after appropriate staining used
2.Isolation of leptospires (Culture)
- Leprospiremia occurs during the first stage of the disease2, beginning before the onset of symptoms, and ends by the first week of the illness.
3. Serology
- Microscoplc agglutination test [MAT](Gold Standard)
- Macroscoplc agglutlnation test
4.Complement fixation (CF)
5.Slide agglutination assays
6.Molecular diagnosis-PCR
7. Molecular typing
Treatment of leptospirosis
- Mild cases → Doxycycline or amplicillin or amoxicillin
- Moderate or severe → Penicillin G or ampicillin or amoxicillin or erythromycin
Exam Important
Host
- Zoonoses
- Leptospira affects wild and domestic animals worldwide.
- Man is an accidental host.
- Rats and small rodents are the main reservoirs of Leptospira.
Media used for isolation
- Korthof medium
Modes of transmission
1. Direct contact
- Transmission of leptospires may follow direct contact with urine, blood or tissue from an infected animal.
2.Indirect contact
3. Droplet infection
- Through inhalation by breathing air polluted with droplets of infected urine.
- Direct man to man infection is rare.
Clinical features
- Incubation period of Leptospirosis is 1-2 weeks.
- Vasculitis is responsible for the most important manifestations of the disease, mainly affect the kidney and liver.
Leptospirosis may present as one of the two clinical types:
(1) Anicteric form
- It is mild form and accounts for 90% of cases of leptospirosis.
- It presents as acute influenza like illness, with fever, chills, headache, myalgia, vomiting, sore throat and pulmonary involvement like cough, hemoptysis and chest pain.
(2) Icteric form
- It is severe form and accounts for 5-10% of cases of leptospirosis.
- It is also called icterohemorrhagic fever or hepto-renal syndrome/Weils’ disease
Diagnosis of leptospirosis
1. Microscopic Demonstration
- Dark-field microscopy or by immunofluorescence or light microscopy after appropriate staining used
2.Isolation of leptospires (Culture)
3. Serology
- Microscoplc agglutination test [MAT](Gold Standard)
- Macroscoplc agglutlnation test
4.Complement fixation (CF)
5.Slide agglutination assays
6.Molecular diagnosis-PCR
7. Molecular typing
Treatment of leptospirosis
- Mild cases → Doxycycline or amplicillin or amoxicillin
- Moderate or severe → Penicillin G or ampicillin or amoxicillin or erythromycin
