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Aerosolized Burkholderia pseudomallei, the causative agent of melioidosis, can infect many species of mammals (including humans), causing rapid, severe pneumonia with high mortality. Diagnosis in humans is challenging, as few organisms can be detected in blood or other non-invasive samples. Although it cannot be said that the model is established, studies to date indicate that rhesus macaques may represent a good model of human melioidosis. This is supported by the results of this study. The early progression of meliodosis in the rhesus macaque was studied in an effort to better understand the disease and the application of rapid diagnostic methods. Results indicate that a PCR analysis of key diagnostic samples such as nasal swabs, throat swabs, tracheo bronchial lymph node aspirates and broncho-alveolar lavage may be a useful component of a rapid diagnostic algorithm in case of aerosol exposure.

Burkholderia pseudomallei , the causative agent of melioidosis, is recognized as a serious health threat due to its involvement in septic and pulmonary infections in areas of endemicity and is recognized by the Centers for Disease Control and Prevention as a category B biothreat agent. An animal model is desirable to evaluate the pathogenesis of melioidosis and medical countermeasures. A model system that represents human melioidosis infections is essential in this process. A group of 10 rhesus macaques (RMs) and 10 African green monkeys (AGMs) was exposed to aerosolized B. pseudomallei 1026b. The first clinical signs were fever developing 24 to 40 h postexposure followed by leukocytosis resulting from a high percentage of neutrophils. Dyspnea manifested 2 to 4 days postexposure. In the AGMs, an increase in interleukin 1β (IL-1β), IL-6, IL-8, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α) was observed. In the RMs, IL-1β, IL-6, and TNF-α increased. All the RMs and AGMs had various degrees of bronchopneumonia, with inflammation consisting of numerous neutrophils and a moderate number of macrophages. Both the RMs and the AGMs appear to develop a melioidosis infection that closely resembles that seen in acute human melioidosis. However, for an evaluation of medical countermeasures, AGMs appear to be a more appropriate model.