Pulmonary masses in a tuberculin skin test-negative olive baboon

An adult female olive baboon was shipped to the University of Illinois at Chicago (UIC) from another institution and placed in quarantine. This baboon had been wild-caught approximately 1 year earlier. Initial quarantine examination at UIC revealed tachypnea and an elevated white blood cell count. Intradermal tests for tuberculosis were negative. Radiographs demonstrated increased density, three radiopaque masses in the lung fields,and hepatosplenomegaly. Each differential diagnosis considered had a poor prognosis, and the animal was euthanized and a necropsy performed. At necropsy, five intact cysts in the liver and two in the lungs were identified. In addition, the right apical lung lobe was collapsed, contained an apparently old, ruptured cyst, and had numerous fibrous adhesions to the thoracic wall. Microscopic examination of the cysts and cyst-fluid revealed that the cysts were multilaminated structures that contained viable Echinococcus granulosus protoscolices; therefore a diagnosis of hydatidosis was made. Recent advances in tests used to screen humans for hydatidosis have led to the development of an immunoblot and enzyme immunoassay, which are highly sensitive and specific. In this report, we verified the usefulness of these tests for detecting hydatidosis in baboons. Serum from the infected baboon and from three other apparently healthy members of the colony were sent to the Centers for Disease Control and Prevention to be tested. Serum from the infected baboon yielded positive results in both the immunoblot and enzyme immunoassay, whereas tests on serum from the normal baboons were negative. Therefore, both the immunoblot and enzyme immunoassay represent potentially valuable tools for diagnosing hydatidosis in nonhuman primates.