The Leptospirosis Information Center

The history of leptospirosis and Weil's diease

Leptospirosis has of course been around for millions of years, but the bacterial cause of illness was only identified recently and research into the bacteria, their DNS strains and the exact way they cause illness and immunity is still in progress - we doubt we will fully understand the bacteria for many more years.

Adolf Weil's publication in 1886 is credited with the first detailed account of the infection, and it is right that the icteric form of illness he described has been given his name - however the infection was known and reported long before that, with accounts associating fever and jaundice with farming, flooding and livestock floating about in literature and language all over the world, from ancient China to India and Europe. Hippocrates postulated about it, as did Galen. Moving towards recent times, Weil's disease (albeit without a name) was noted in medical reports from the Napoleonic campaigns and travellers to the Americas. The fact that Weil's paper received so much attention is more an accident of geography and politics than of any unique insight - in the late 19th Century a lot of medical material was in German, printing made such material readily available, and Weil was in the right place at the right time to be noticed. We're sure that rice-farmers reading his paper would have laughed it off as old news.

The illness Weil described was the sever icteric form with jaundice, and it is not as simple to find descriptions of the milder forms, simply because they are so easily misdiagnosed and weren't accepted as a disease until the advent of bacteriology allowed the causes of illness to be determined. The association of risk was known for decades, even centuries, before the leptospira bacterium was found and associated as a cause. Spirochetes were found to cause a wide range of illness in the latter half of the 19th Century, but the first credited account of a leptospire isolated from a patient was by Stimpson in 1907. The paper had a rough ride and was republished a few times before being noticed, but looking at it today we see several important discoveries, such as the concentration of bacteria in the renal tubules, that others took far longer to 'discover' at the time. Stimpson called the bacteria 'Spirocheta interrogans' due to their stained shapes looking like question marks, and the name has remained.

The first World War increased research on all sides, as the trench conditions made case numbers increase beyond all previous records. One of the outcomes of all this wartime research, apart from the knowledge of the bacteria and their virulence, was that each side disclaimed each other for discoveries and even now it is hard to determine precisely who discovered what first.

Rats as a carrier (reservoir host) were identified in Japan in the years between discovery of the bacteria and the War. Most of the basic pathology and epidemiology we use today was defined before 1940, and in recent years the research has concentrated on the bacterial DNA sequence and internal cellular processes that confer virulence, immunity and may lead to development of better vaccines.