ABSTRACT
Borrelia is a genus of spirochetes belonging to the Spirochaetoceae. Morphologically, the typical organism is composed of five to ten loosely wound, irregular coils measuring 1035µ in length and 0.3-0.5µ in width. Although susceptible to desiccation and to many chemical agents, the organisms are able to survive in citrated blood for as long as three months at 2-3°C. Disease caused by these spirochetes may be divided into:
(1) an epidemic form in which the body louse, Pediculus humanus corporis, is usually the principal vector; and
(2) an endemic form in which infection is mostly transmitted through ticks of the Ornithodoros genus.
