Spirochætosis of Fowls—One of the best known of the spirochætes transmitted by arthropods is Spirochæta gallinarum, the cause of a very fatal disease of domestic fowls in widely separated regions of the world. According to Nuttall, it occurs in Southeastern Europe, Asia, Africa, South America and Australia.

In 1903, Marchoux and Salimbeni, working in Brazil, made the first detailed study of the disease, and showed that the causative organism is transmitted from fowl to fowl by the tick Argas persicus. They found that the ticks remained infective for at least five months. Specimens which had fed upon diseased birds in Brazil were sent to Nuttall and he promptly confirmed the experiments.