Leptospira

LEPTOSPIRA (Leptospira), a genus of microorganisms from the spirochete group (Spirochaetaceae). This genus was separated from the genus Spirochaeta by Noguchi (1917) and contains several species that are pathogenic for humans. Morphologically, Leptospira resemble other spirochetes, which is why German authors merge them into one with the genus Spirochaeta. The main feature of Leptospira is that its spirally twisted body bends at both poles in the form of a hook, gradually thickening toward its free end. These hooks often create the false impression of terminal swellings. According to some authors (M. Zuelzer), the body of Leptospira is provided with an axial thread; other authors dispute the presence of an axial thread. Of the species belonging to the genus Leptospira, Leptospira ictero-haemorrhagica (Inada and Ido; 1915) has been best studied - the causative agent of epidemic jaundice (Weil's disease). In German literature, this species is more often called Spirochaeta icterogenes [a name given by Uhlenhuth and Fromme in 1916]. The reservoir for Leptospira ictero-haemorrhagica is rats, which according to Uhlenhuth's data can themselves show symptoms of Weil's disease, but more often are merely carriers of this Leptospira. Another species - Leptospira hebdomadis (Ido, Ito and Wani; 1918) - causes Asian 'seven-day fever' (or 'nanukayama'); in nature this species has been found in one of the field rodents (Microtus Montebelloi). A third species of Leptospira, very similar in structure to Leptospira ictero-haemorrhagica, was isolated by Noguchi (1918) from the tissues of humans suffering from yellow fever and was named by him Leptospira icteroides. However, apparently the same form was observed as early as 1907 by Stimson, who however doubted its belonging to spirochetes and gave it only a provisional name Spirochaeta interrogans. The transmitters of this species should be considered mosquitoes Aedes argenteus. Apparently there are also a number of human diseases caused by Leptospira (leptospiroses), which however are not yet sufficiently well studied. For example, Schuifner, investigating cases of 'black water fever', or hemoglobinuria, in Sumatra in 1918, found a spirochete which he named Leptospira ictero-hemoglobinuriae. Whittingham obtained from patients with mosquito fever ('Pappataci fever') a culture of spirochetes very similar in structure to Leptospira causing Weil's disease. Finally, de Faria (1924) claims that he found Leptospira in cases of dengue disease and proposes the name Leptospira Couvyi for it. All these data require further verification.