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404 Part tHrEE Host Defenses to Infectious Agents

that the disease is underreported and that the suspected real
number of cases may be much higher.
20-30µm An early hallmark of infection is the appearance of a skin
0.2-0.3µm rash, known as erythema migrans (Fig. 28.2), which appears at
the inoculation site, often during the first week of infection
(stage I Lyme disease), as a result of local inflammatory responses.
A Other symptoms secondary to the local inflammatory responses
Outer membrane occurring during stage I can affect more distal sites and may
include fever, headache, malaise, myalgia, and/or arthralgia.
Periplasmic flagella Inner membrane Hematogenous dissemination of the spirochete is stage II Lyme
disease and results in colonization of different tissues and/or
Protoplasm organs and presentation of a range of symptoms, such as conduc-
tion system abnormalities, meningitis, and acute arthritis. Joint
inflammation appears in 60% of untreated individuals in the
United States and predominately affects large joints, especially
the synovium of the knee. Some untreated individuals develop
B stage III Lyme disease, which is generally characterized by
FIG 28.1 Borrelia burgdorferi structure is characterized by a prolonged infection with the spirochete. Late-stage symptoms
distinctive flat-wave morphology consisting of approximately 18 may include chronic arthritis, neuroborreliosis, or cutaneous
bends and a length of 20–30 µm (A). A cross-section of this lesions, such as acrodermatitis chronica atrophicans. The range
spirochete reveals the endoflagella, which are responsible for of symptoms that appear upon infection in Europe and the
the unique morphology and motility of this organism (B). United States vary in relative terms: arthritis and carditis are

TABLE 28.1 Major Diseases Caused by Spirochetes*
Disease agents Distribution transmission Symptoms
Lyme disease Borrelia burgdorferi North America, Europe Tick engorgement Development of a skin rash known as erythema
B. garinii Asia, Europe migrans, accompanied by other symptoms, such as
B. afzelii Asia, Europe malaise, myalgia, and/or arthralgia. Symptoms can
B. andersonii North America progress to include carditis and arthritis. Persistent
B. japonica Japan infection can result in chronic arthritis,
B. lusitaniae Southern Europe neuroborreliosis, or cutaneous symptoms
B. valaisiana Europe, Ireland, UK (acrodermatitis chronica atrophicans).
B. mayonii North America
B. miyamotoi North America
Relapsing fever B. hermsii Western USA Tick engorgement Clinical manifestations of infection include high-
B. turicatae Southwestern USA, Mexico density spirochetemia, high fever, myalgias, and
B. parkeri Western USA arthralgias and can even include cerebral
B. mazzotti Central America hemorrhage and fatality.
B. venezuelensis Central America
B. duttonii Sub-Saharan Africa
B. crocidurae North Africa, Middle East
B. persica Middle East, Central Asia
B. hispanica Iberian peninsula, North Africa
B. latyschewii Iran, Iraq, Eastern Europe
B. caucasia Iraq, Eastern Europe
Venereal syphilis Treponema pallidum Worldwide Sexual contact Disease progresses from a primary lesion (chancre)
pallidum to a secondary eruption and then to a latent period,
and if left untreated, tertiary symptoms may
appear.
Endemic syphilis or T. pallidum Eastern Mediterranean region, Nonsexual skin Symptoms begin with a slimy patch inside the
Bejel syphilis endemicum West Africa contact mouth, followed by blisters on the trunk and limbs.
Bone infection in the legs soon develops, and in
the later stages, lumps may appear in the nose and
on the soft palate of the mouth.
Yaws T. pertenue Humid equatorial countries Nonsexual skin Destructive lesions of the skin and bones, which is
contact rarely fatal but can be debilitating.
Pinta T. carateum Mexico, Central America, Nonsexual skin Dark-colored skin lesions found on those areas of the
South America contact body that are exposed to sunlight. Eventually, the
skin lesions become discolored.
Leptospirosis Leptospira Worldwide Urine from an Symptoms include fever, headache, chills, nausea
interrogans infected animal and vomiting, eye inflammation, and muscle aches.
In more severe cases, the illness can result in liver
damage and kidney failure.
*Spirochetes are the causative agents of many diseases, which can have social as well as lasting health-related consequences.