Epidemiology and Management of Leptospirosis.pptx

A brief description on the epidemiology of Leptospirosis, clinical features, laboratory diagnosis and its management

1. Leptospirosis

2. Leptospira ( spirocheates )

3. Problem Statement Leptospirosis is reported in a number of countries of the South-East Asia Region from time to time. The magnitude of the leptospirosis problem differs from country to country and depends on awareness and attitude of public heath care decision makers. Most human cases have been reported from India, Indonesia, Thailand and Sri Lanka during the rainy season.

4. Major outbreaks in South-East Asia were reported in the past in Jakarta (2003), Mumbai (2005) and Sri Lanka (2008). Seasonal outbreaks are reported in northern Thailand and in Gujarat, India following heavy rainfall and flooding. According to currently available reports, incidences range from approximately 0.1–10 per 100 000 per year globally. During outbreaks and in high-exposure risk groups, disease incidence may reach over 50 per 100 000.

5. Introduction Leptospirosis is animal infection by several groups of spirochaetes and transmitted to man under certain environmental conditions The disease manifests as a febrile illness with renal and hepatic involvement Weil’s disease is one of the manifestations of human leptospirosis It has high prevalence in warm humid tropical countries Outbreaks mostly occur as a result of heavy rainfall and consequent floodings

6. Epidemiological determinants Agent factors: AGENT: Leptospira are thin and light motile spirochaetes 0.1 – 0.2 micron wide and 5-15 micron long with hooked ends Only the strains of L. interrogans are pathogenic SOURCE OF INFECTION: Leptospira are excreted in the urine of infected animals

7. Agent Factors ANIMAL RESERVOIRS: Leptospirosis affects wild and domestic animals worldwide especially rodents such as rats, mice Domestic animals including cattle, sheep, goats, buffalo, pigs and horses may be infected through grazing in areas contaminated by the urine of the carrier host Rats and small rodents (Rattus norvegicus, Mus musculus) are the important reservoirs

8. Host factors AGE: Children acquire the infection from dogs more frequently than do adults Human infection is only accidental OCCUPATION: Human infections are usually due to occupational exposure to the urine of infected animals, eg :, agricultural and livestock farmers, workers in rice fields, sugarcane fields and underground sewers, meat and animal handlers, veterinarians etc IMMUNITY: a solid serovar specific immunity follows infection

9. Environmental factors Infection is acquired through contact with an environment contaminated by urine and faeces from carrier animal or other infected animals Leptospira shed in the urine can survive for weeks in soil and water, so environmental contamination may reach high levels in areas where carrier animals frequently urinate The association of poor housing, limited water supply, inadequate method of waste disposal, all combine to make the disease a significant risk for the poor population in both urban and rural areas

10. Mode of transmission Direct contact: through skin abrasions or through intact mucous membrane by direct contact with urine or tissue of infected animals Indirect contact: through the contact of the broken skin with soil, water or vegetation contaminated by urine of infected animals or through ingestion of food or water contaminated with leptospirae Droplet infection: infection may occur through inhalation as when milking infected cows or goats by breathing air polluted with droplets of urine

11. Incubation Period Usually, 10 days with a range of 4 to 20 days

12. Clinical Picture The clinical spectrum is very wide, with mild anicteric presentation at one end to severe leptospirosis with severe jaundice and multiple organ involvement on the other. Many infections go unnoticed because of lack of significant illness. Clinical types of leptospirosis are as follows : a.Anicteric leptospirosis b.Icteric leptospirosis

13. a.Anicteric Leptospirosis Milder form of the disease Patient presents with chills, myalgia, conjunctival suffusion, headache, renal manifestation, pulmonary manifestations and hemorrhagic tendencies. All the clinical features either decrease or disappear within 2 or 3 days and then may appear and may progress to severe disease.

14. b.Icteric Leptospirosis More severe form of leptospirosis Patient has jaundice and presents with fever, myalgia, headache, conjunctival suffusion, acute renal failure, nausea, vomiting, diarrhoea , abdominal pain, hypotension and circulatory collapse, pulmonary insufficiency. Combined renal and liver failure associated with leptospirosis is referred to as Weils disease

15. Clinical features contd …. Leptospirosis during pregnancy can cause foetal complications including foetal death or abortion. The case fatality rate for leptospirosis is approximately 5% to 15% among patients with severe illness. Among patients with severe pulmonary hemorrhagic syndrome, the case fatality can exceed 50%.

16. Diagnosis Diagnosis is made by isolation of Leptospira from blood during the acute illness and from urine after the first week The organism is identified by dark field examination of the patient’s blood or by culture on a semisolid medium Agglutination tests become positive after 7-10 days of illness and peak at 3-4 weeks and may persist at high level for many years Indirect haemagglutination, immunofluorescent antibody and ELISA tests are also available

17. Control Antibiotics: Penicillin is the drug of choice but other antibiotics like doxycycline are also effective. The dosage of penicillin is 6 million units daily IV. Environmental measures: this includes preventing exposure to potentially contaminated water, reducing contamination by rodent control and protection of workers in hazardous occupation

18. Vaccination Immunization of farmers and pets prevent disease It is important to incorporate strains of serotypes that predominate in the particular area since immunity to one type of Leptospira may not protect against infection by another

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