Brucellosis, also known as Malta fever, is a bacterial zoonotic disease transmitted from animals to humans. It is caused by Brucella bacteria and can be acquired through several routes, most notably the consumption of unpasteurized dairy products or direct contact with infected animals. Brucellosis is considered a significant public health problem in many regions of the world, particularly in the Middle East, due to its prevalence and diverse health impacts. The disease is characterized by a wide range of symptoms, including fever, night sweats, and general fatigue. However, musculoskeletal involvement is among the most common and clinically important complications, with many patients experiencing varying degrees of joint, bone, and spinal pain. Causative Agent Brucellosis is caused by several species of Brucella, the most important of which include: Brucella melitensis Brucella abortus Brucella suis Brucella canis Among these, Brucella melitensis is the most common and the most virulent species affecting humans. Routes of Transmission Human infection may occur through several routes, including: Consumption of unpasteurized milk and dairy products. Direct contact with infected animals or their secretions. Inhalation of contaminated aerosols. Occupational exposure in veterinary laboratories and slaughterhouses. Clinical Manifestations of Brucellosis The disease may present either gradually or acutely and is characterized by: Fever. Night sweats. Fatigue and weakness. Loss of appetite. Headache. Muscle and joint pain. Without early diagnosis and appropriate treatment, symptoms may persist for prolonged periods. Relationship Between Brucellosis and Joint Involvement Musculoskeletal complications are among the most common clinical manifestations of brucellosis. The bacteria can spread to bones and joints, causing inflammation that leads to pain and restricted movement. In addition, the inflammatory response triggered by the infection contributes significantly to the development of joint-related symptoms. The most commonly affected sites include: Knee joint. Hip joint. Ankle joint. Sacroiliac joint. Spine, particularly the lumbar region. Joint and Bone Complications Arthritis Arthritis is the most common complication and is characterized by joint pain, swelling, and reduced mobility of the affected joint. Sacroiliitis Inflammation of the sacroiliac joint causes pain in the lower back and buttocks and is considered a characteristic manifestation of brucellosis in adults. Spondylitis This condition affects the vertebrae of the spine and may result in chronic pain and decreased functional capacity. Osteomyelitis Although less common, osteomyelitis may lead to significant structural bone damage if treatment is delayed. Diagnosis The diagnosis of brucellosis is based on: Detailed patient history. Clinical examination. Serological tests for detecting antibodies. Blood or bone marrow cultures. Radiological imaging when bone or joint involvement is suspected. Prevention Preventive measures include: Avoiding the consumption of unpasteurized milk and dairy products. Following protective measures when handling animals. Regular screening of livestock and control of animal infections. Enhancing public health awareness regarding routes of transmission. Conclusion Brucellosis is an important bacterial disease that can directly affect the musculoskeletal system, particularly the joints and spine, leading to pain and inflammation that may become chronic if diagnosis and treatment are delayed. Therefore, early detection and appropriate therapy remain the cornerstone of preventing complications and improving patients’ quality of life. Al-Mustaqbal University The First University in Iraq