Concomitant Plasmodium vivax malaria and murine typhus infection with pulmonary involvement

We report a case of Plasmodium vivax and murine typhus coinfection in a 30-year-old woman who presented with intermittent, high-grade fever. Her peripheral blood smear showed ring-form trophozoites of P. vivax, with an initial murine typhus serological test being negative. Although the P. vivax infection was successfully treated, she still had intermittent, high-grade fever, developed dyspnoea and bilateral interstitial pneumonitis shown in the chest X-ray. Thus, coinfection was suspected, and empirical antibiotics were given. The second serological test confirmed the concomitant murine typhus infection, and antibiotics treatment were successful with the complete recovery. This case emphasises that an initial negative murine typhus serological test does not necessarily rule out the presence of the disease. A follow-up murine typhus serological or molecular test within 1–2 weeks is therefore recommended.