Leptospirosis

also called Weil's disease, infectious jaundice, pea picker's disease , or swineherd's disease contagious disease of animals, occasionally communicable to humans, caused by a pathogenic spirochete of the genus Leptospira.

The reservoir of leptospires includes rodents and certain domestic animals. These animals excrete live, fully virulent organisms in their urine and contaminate the environment. Outside the animal body, leptospires can live for several weeks in fresh water. Thus infection takes place by direct contact with urine of infected animals or by indirect contact with contaminated food or water. Leptospires can readily penetrate mucous membranes but probably cannot gain entrance to the body through intact skin. A scratch or abrasion, as well as the nasal mucosa and eye, are excellent portals of entry; thus the origin of many infections can be traced to wading, swimming, or other contact with water containing virulent leptospires. The incidence in humans depends upon the opportunity for exposure in swimming, the harvesting of rice, and contact with animals.

Clinical evidence of disease in humans varies depending upon the infecting type of leptospire. Usually after an incubation period of about a week, fever, weakness, and pains in the legs, back, and abdominal muscles are noted. Nausea, vomiting, and diarrhea are not uncommon. One characteristic symptom is congestion of the conjunctival blood vessels around the corneas of the eyes. Jaundice may occur after the first week of illness. The death rate is approximately 30 percent of the severely ill and jaundiced patients.