Comparative study on kits used for diagnosis of Brucellosis in humans

Brucellosis is an infectious zoonotic disease caused by bacteria of the genera Brucella. Brucellosis is mainly a disease of livestock infecting cattle, sheep, goats, pigs, dogs and marine mammals. In humans, the disease is acquired directly or indirectly from infected animals or animal products. Brucella species of public health concern are B. abortus, B. melitensis, B. suis, B. canis, B. ovis and B. neotamae which cause disease both in animals and human. Clinical symptoms include fever, headache, chills, depression, profound weakness, weight loss and muscle and joint pain. If untreated, the infection persists and progresses to a chronic illness that may present as endocarditis, epididymo-orchitis and infertility in males, spontaneous abortion in females, neurobrucellosis and may result in death. Diagnosis of human brucellosis is based on isolation of the bacteria from clinical specimens followed by microscopy. This method may miss some positive specimens especially when the bacteremia is low. Other methods include serology and molecular biology techniques. Serological test are not internationally standardized, thus the sensitivity and specificity of the tests may be unknown. Other limitations include cross reactivity of some tests with closely related bacteria and inability to distinguish between active infection and previous exposure. These may lead to false positive or false negative results, leading to poor clinical management of patients. Molecular methods, such as polymerase chain reactions (PCR) are very sensitive and specific but require expertise, are expensive and are unavailable in many clinical laboratories in Kenya. This study will compare the sensitivity and specificity of the serological kits used for Brucella diagnosis in health care facilities in Kenya with indirect enzyme immunosorbent assay (ELISA) and the Rose Bengal test, tests that have been shown to have high sensitivity and specificity. Polymerase chain reaction will be used to confirm the Brucella-positive samples and to identify the Brucella species affecting patients in the participating health facilities. The study will provide information on the specificity, sensitivity and cost of each diagnosis kit to the participating health facilities and to the Kenya Ministry of Health to help inform decisions on diagnosis of brucellosis in humans in Kenya.