Leptospirosis: A Public Health Story Encircling the Globe.

One of the most enchanting tourist trips in Europe is along the Rhine Valley with the winding river surrounded by hills topped by many medieval castles. On the Neckar River, a tributary to the Rhine, lies the beautiful historic city of Heidelberg, again with a magnificent castle looking down on the old city from a nearby hill. Heidelberg, the home of Germany’s oldest university established in 1386, was left untouched during World War II. It is wonderful to walk around the old city with its narrow cobble-stoned streets and visit the Faculties of the University. Heidelberg has always been a center for science and technology. It is a center of printing, and the chances are that when you read your newspaper this morning, it was printed on a press originally designed in Heidelberg. In 1870, a newly graduated physician, Adolf Weil (1848-1916), described 4 cases with high fever, severe jaundice, and enlarged spleen and liver, which came to be known as Weil’s disease. The natural history of the disease at the time was often fatal. Dr Weil was himself not in good health, suffering from tuberculosis, and after a lifetime of ill health, he died of tuberculosis in Wiesbaden in 1916. The end of the 19th century has been described as the Golden Age of Bacteriology as Koch’s postulates were applied to the causation of many diseases. In 1879, the spirochaete Borrelia was found to be the cause of relapsing fever, and in 1905, Treponema pallidum was found to be the cause of syphilis.1-3 On the other side of the world, research was continuing on the biology of spirochaetes. Then in 1915, Inada and Ido announced the discovery of the causative agent of Weil’s disease, a new species of spirochaete at the Kyushu Imperial University Medical School. Their report appeared in English soon afterwards.4 Within 2 years of the discovery of the leptospirosis spirochaete in Japan, a report appeared in the journal Public Health describing the finding of these bacteria in the kidneys of rats trapped in British cities.5 The authors discussed the risk of finding human Weil’s disease in the United Kingdom, and of course, it was a prediction that soon became a public health problem. Diseases caused by members of the Spirochaete group now include Weil’s disease, syphilis, and Reiter’s disease. It is now recognized that leptospirosis causes a spectrum of disorders and not just the severe syndrome of Weil’s disease. Now, more than 200 serovars of leptospira species have been identified and which are distributed worldwide in many species of mammals and rodents. Humans contract leptospirosis through contact with animal urine and occasionally from contact (eg, swimming) with contaminated water. While leptospirosis is difficult to diagnose clinically, it has become the most widespread zoonotic disease in the world with at least one million cases annually (and probably many more), and the number is continuing to increase.6,7 The countries with the highest reported incidence are