Most infections remain asymptomatic. Depending on the organism, symptoms begin as early as 2 weeks after exposure, but can occur as late as months after exposure. The organism tends to seed tissues with large numbers of macrophages, such as lung, spleen, liver, CNS, bone marrow, and synovium. The disease most often starts with a nonspecific prodrome, which is, however, absent in infection with B. melitensis. This is followed by the bacteremic stage, with intermittent fever, lasting for several weeks before subsiding, and then recurring in addition to other symptoms. This pattern of periodic febrile waves and remission can last for months or even years. Common manifestations in naturally acquired disease include joint pain, which is often incapacitating, and most commonly affects the sacroiliac joint, but also ankles, knees, and hips. Low back pain is seen in 60% of infected people and can be associated with vertebral osteomyelitis, intervertebral disc, or sacroiliac infection, or paravertebral abscess. Although pneumonia is not a common complication of brucellosis, 20% of patients develop cough and pleuritic chest pain. GI symptoms develop in 70% of adult cases. Hepatomegaly or splenomegaly is the result of granuloma formation and occurs in 45 to 63% of cases [57] . Endocarditis occurs in fewer than 2% of cases.