Human leptospirosis: guidance for diagnosis, surveillance and control

Abstract

Why were these guidelines written? Leptospirosis is a worldwide public health problem. In humid tropical and subtropical areas, where most developing countries are found, it is a greater problem than in those with a temperate climate. The magnitude of the problem in tropical and subtropical regions can be largely attributed to climatic and environmental conditions but also to the great likelihood of contact with a Leptospira-contaminated environment caused by, for example, local agricultural practices and poor housing and waste disposal, all of which give rise to many sources of infection. In countries with temperate climates, in addition to locally acquired leptospirosis, the disease may also be acquired by travellers abroad, and particularly by those visiting the tropics. Leptospirosis is a potentially serious but treatable disease. Its symptoms may mimic those of a number of other unrelated infections such as influenza, meningitis, hepatitis, dengue or viral haemorrhagic fevers. Some of these infections, in particular dengue, may give rise to large epidemics, and cases of leptospirosis that occur during such epidemics may be overlooked. For this reason, it is important to distinguish leptospirosis from dengue and viral haemorrhagic fevers, etc. in patients acquiring infections in countries where these diseases are endemic. At present, this is still difficult, but new developments may reduce the technical problems in the near future. It is necessary, therefore, to increase awareness and knowledge of leptospirosis as a public health threat. The aim of these guidelines is to assist in this process. In many respects, leptospirosis may be viewed as an emerging disease, and this has led to an increased interest and demand for information, notably in developing countries. New and less complicated diagnostic methods have been developed in recent years, allowing leptospiral infection to be identified without the real need for recourse to specialized reference laboratories.