It can cause miscarriage and infection in infants. Leptospirosis transmission through eating raw meat of wildlife animals have also been reported (e.g. psychiatric patients with allotriophagy). Pathogenesis
When animals ingest the bacteria, they circulate in the bloodstream, then lodge themselves into the kidneys through the glomerulular or peritubular capillaries. The bacteria then pass into the lumens of the renal tubules and colonise the brush border and proximal convoluted tubule. This causes the continuous shedding of bacteria in the urine without the animal experiencing significant ill effects. This relationship between the animal and the bacteria is known as a commensal relationship, and the animal is known as a reservoir host.Humans are the accidental host of Leptospira. The pathogenesis of leptospirosis remains poorly understood despite research efforts. The bacteria enter the human body through either breaches in the skin or the mucous membrane, then into the bloodstream. The bacteria later attach to the endothelial cells of the blood vessels and extracellular matrix (complex network of proteins and carbohydrates present between cells). The bacteria use their flagella for moving between cell layers. They bind to cells such as fibroblasts, macrophages, endothelial cells, and kidney epithelial cells. They also bind to several human proteins such as complement proteins, thrombin, fibrinogen, and plasminogen using surface leptospiral immunoglobulin-like (Lig) proteins such as LigB and LipL32, whose genes are found in all pathogenic species.Through innate immune system, endothelial cells of the capillaries in the human body are activated by the presence of these bacteria.
Leptospirosis is a blood infection caused by the bacteria Leptospira. Signs and symptoms can range from none to mild (headaches, muscle pains, and fevers) to severe (bleeding in the lungs or meningitis). Weils disease, the acute, severe form of leptospirosis, causes the infected individual to become jaundiced (skin and eyes become yellow), develop kidney failure, and bleed. Bleeding from the lungs associated with leptospirosis is known as severe pulmonary haemorrhage syndrome.More than ten genetic types of Leptospira cause disease in humans. Both wild and domestic animals can spread the disease, most commonly rodents. The bacteria are spread to humans through animal urine, or water and soil contaminated with animal urine, coming into contact with the eyes, mouth, nose or breaks in the skin. In developing countries, the disease occurs most commonly in farmers and low-income people who live in areas with poor sanitation. In developed countries, it occurs during heavy downpours and is a risk to sewage workers and those involved in outdoor activities in warm and wet areas. Diagnosis is typically by testing for antibodies against the bacteria or finding bacterial DNA in the blood.Efforts to prevent the disease include protective equipment to block contact when working with potentially infected animals, washing after contact, and reducing rodents in areas where people live and work. The antibiotic doxycycline is effective in preventing leptospirosis infection. Human vaccines are of limited usefulness; vaccines for other animals are more widely available. Treatment when infected is with antibiotics such as doxycycline, penicillin, or ceftriaxone.