BACKGROUND: We describe a 40-year-old Thai woman living in Japan who was transferred to Juntendo University Hospital after lung cancer was suspected. Chest X-ray showed a nodular lesion and pleural effusion in the left lung. Laboratory data showed eosinophilia. She denied having consumed raw or undercooked food at the initial interview. Microplate enzyme-linked immunosorbent assay (ELISA) for Paragonimus westermani specific immunoglobulin (Ig) G antibody was positive at a high titer, confirming the diagnosis of P. westermani infection. She was successfully treated with oral praziquantel. All primary practitioners should be aware that paragonimiasis is an important pulmonary disease that can cause nodular lesions on chest X-ray.

ABSTRACT: A case of infectious mononucleosis (IM) in a previously healthy 43-year-old male is presented. The patient complained of fever and a sore throat of 3 weeks' duration. Although blood tests showed a marked increase in atypical lymphocytes, tests for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were negative. Human immunodeficiency virus type 1 (HIV-1) antibody was positive on enzymelinked immunosorbent assay (ELISA), and the HIV-1 viral load was 6.4×10⁴copies/mL. Western blot (WB) analysis did not initially confirm HIV-1 infection ; however, HIV-1 infection was confirmed one month after presentation. Although several pathogens can cause infections presenting as IM, in Japan there have been few reports of acute retroviral syndrome presenting as IM. This case is being reported to stress the importance of the early diagnosis of acute retroviral syndrome.