Tularaemia as a differential diagnosis in tumour colli

Tularaemia is a bacterial zoonosis caused by the bacterium Francisella tularensis. Different species of rodents and small mammals are the main reservoir; the transmission of disease is caused by direct contact with diseased animals, via insect vectors, or by ingestion of contaminated food and water. The disease is known to cause a complex clinical presentation in which head and neck manifestations are common. It occurs at a low annual rate in the northern and middle regions of Norway, but in recent years there have been several reported cases also in the southern parts of the country. The incidence of tularaemia is much higher in Sweden compared to Norway; the reason remains obscure. In this paper we report two admitted cases in which fever and a solitary neck mass were the predominant clinical findings. We review the number of cases reported to the Norwegian Institute of Public Health from 1976 to 2002, with particular emphasis on the role of tularaemia in the context of a neck tumour and oropharyngeal symptoms. The suspicion of tularaemia should be raised in patients with a solitary neck mass of presumed infectious aetiology, in particular when administration of beta-lactam antibiotics has failed. The diagnosis is usually dependent on serological evidence of F. tularensis infection. Recently, PCR techniques have been developed that facilitate rapid detection of F. tularensis in clinical specimens.