Prolonged monosymptomatic fever due to Yersinia enterocolitica.

A previously healthy 14-year-old girl showed monosymptomatic hectic fever for over 3 weeks with negative clinical findings. Extensive laboratory investigation revealed only elevated ESR and a high titer of agglutinating antibodies against Yersinia enterocolitica, serotype 0-3. These abnormalities disappeared upon tetracycline therapy, after which she remained in excellent health. This unusual manifestation of yersiniosis, which was of unknown source, demonstrates that Yersinia infection should be considered in patients with prolonged febrile illnesses of obscure etiology.