Boil before eating: paragonimiasis after eating raw crayfish in the Mississippi River Basin

Paragonimiasis is a parasitic infection of the lungs caused by zoonotic lung flukes of the genus Paragonimus. Most cases are reported from Asia and caused by P. westermani following consumption of raw crustaceans. With the exception of imported cases, human paragonimiasis was rarely described prior to 1984 in the United States (US), which has only one indigenous lung fluke species, P. kellicotti. Between 1984 and 2010, 15 cases of P. kellicotti paragonimiasis were reported in the United States. This study will analyze all US cases and compare an earlier series of six cases reported during the period 1984-2005 with a recently reported cluster of nine cases from Missouri during the period 2006-2010 in order to determine any significant behavioral and/ or recreational risk factors for paragonimiasis and to recommend early diagnostic, treatment and preventive strategies. Significant behavioral and recreational risk factors included eating raw crayfish while on canoeing trips on local rivers (p = 0.002), eating raw crayfish while on canoeing trips in Missouri (p = 0.002), and eating raw crayfish while intoxicated (p = 0.007). The male:female case ratio was 9.3:1.0 and more than 80% of cases presented with fever, cough, pleural effusions and peripheral eosinophilia. One patient developed cerebral paragonimiasis, and one patient died of pneumonic sepsis. Clinicians should inquire about consumption of raw or undercooked crayfish in all patients with unexplained fever, cough, eosinophilia and pleural effusions returning from camping or canoeing adventures in P. kellicotti-endemic areas of the Mississippi River Drainage Basin; institute diagnostic evaluation by specific parasitological and serological methods and treat all cases as soon as possible to avoid the pulmonary and cerebral complications of paragonimiasis.