Leptospira

Leptospira

Introduction

Leptospira is a zoonosis associated with a bacterium, transmitted by the urine of infected animals, survives in the environment (freshwater). Humans are accidental hosts infected either directly (contact with an infected animal) or, more often, by indirect (contact with fresh water or soil contaminated with urine or tissues of infected animals). Some professions are particularly vulnerable (occupational disease).

It affects young adults and the incidence peaks in summer and early fall. Indirect contact with infected animals, through water or soil contaminated with infected urine is the most common cause of human infection with the direct animal contact. Occupational exposure (farmers, veterinarians, abattoir workers) and recreational exposure (campers, swimmers) are common. Worldwide, rats are the most common source of human infection, followed by dogs, cattle, rodents, cats and wild mammals.

Epidemiological surveillance is exceedingly difficult because leptospira persist for long periods in the renal tubules (with excretion in the urine) without causing disease and wild animals represent an important reservoir to re-infect continuously pets.

Symptoms

The incubation period of the disease is about 15 days. The first symptoms associated fever, chills, muscle aches and headache. Within days the signs change with visceral damage, liver, kidney (renal functional congestive) see a hemorrhagic meningitis (diffuse bleeding). Currently, mortality rate is 2 to 5%.

The disease begins abruptly, including full health without any warning. Chills, body temperature rises rapidly to 39-40C, worried about a severe headache, insomnia, anorexia, thirst. It is a characteristic feature of severe pain in the muscles (myalgia), especially in the calf. The process may involve muscles of the thigh and lumbar region, and their feeling is very painful. In some patients myalgia is accompanied by severe burning pain of the skin. Muscle pain is so severe that patients can hardly move or cannot move at all. They experience decreased amount of urine. In severe cases, within 3-5 days of illness there is jaundice, petechial hemorrhages in the sclera of eyes and skin.

Causative Agent-Etiology

Leptospira is a spiral bacterium that is adapted to life in water. There are currently more than 200 serovariantov and this type of Leptospira are combined into 23 serological groups. Among them: Canicola, Grippotyphosa, Icterohaemorrhagiae, Hebdomadis, Tarasovi is aerobes, and quickly killed by boiling, drying and exposure to direct sunlight. They are sensitive to acids, penicillin, tetracycline, and streptomycin and resistant to low temperatures, remain viable during prolonged freezing. They remain for long in the environment (water, wet soil), and food i.e. from several hours to several days.

Pathogenesis

Leptospira enters man through abraded skin or mucous membranes healthy, spreading rapidly and after 48 hours it is found in all fluids and tissues, with special location in the kidney, liver, heart and skeletal muscle. Leptospira is resistant to the bactericidal activity of normal serum and in the absence of specific antibodies is not phagocytosed or destroyed by PMNs and macrophages. Many aspects of leptospirosis remain unexplained.

Leptospira can be considered a systemic disease, systemic vasculitis which is translated primarily by infections. Vascular injury, mainly capillary, is a prominent factor responsible for leptospira and edema and ...