Talaromyces Marneffei infections in five human immunodeficiency virus-negative patients with the history of predation on wild bamboo rats (Rhizomys spp) - a case series.

Background: Talaromycosis is an aggressive and life-threatening disease, caused by the pathogen Talaromyces marneffei (T. marneffei) which was first isolated from the bamboo rats (Rhizomys sinensis). T. marneffei was traditionally known for its high incidence and mortality rates in human immunodeficiency virus (HIV) patients. Epidemiological data reveal a concerning upward trend of infections among HIV-negative individuals, including immunocompetent hosts. At the meantime, although the bamboo rats have been reported to be associated with T. marneffei infection, there is a noticeable rising trend of the bamboo rats hunting and farming industry. Public awareness regarding the zoonotic transmission risks associated with these rodents remains limited.

Case Presentation: We report five cases of T. marneffei infection occurring within a single year, all involving individuals with a history of hunting wild bamboo rats (Rhizomys spp., likely Rhizomys sinensis). All five patients underwent HIV testing upon admission, with uniformly negative results. Notably, other immunodeficiency diseases, chronic comorbidities or prior immunosuppressive therapy were not found in these patients. The clustered emergence of these cases-affecting immunocompetent individuals within neighboring geographic areas over a brief timeframe, all sharing exposure through bamboo rat hunting-warrants detailed characterization. We herein present clinical profiles of these five cases.

Conclusions: These cases demonstrate epidemiological associations between contact with wild bamboo rats and T. marneffei infections in immunocompetent individuals. The atypical clinical symptoms and variable imaging manifestations of T. marneffei infection may lead to increased underdiagnosis and misdiagnosis. Systematic implementation of exposure history, particularly documenting contact with wild animals for patients with pulmonary infection to make a timely diagnosis. This study also underscores the urgent need for public awareness regarding the potential risks of T. marneffei infections associated with hunting wild bamboo rats and the bamboo rat farming industry.