BACKGROUND: Katayama fever is an acute clinical condition characterised by high 
fever, dry cough and general malaise occurring during early Schistosoma spp. 
infection. It is predominantly reported in travellers from non-endemic regions. 
Whereas the immunological response to Schistosoma infection is well 
characterised, alterations in inflammatory markers and coagulation in response 
to acute infection are poorly understood.
METHODS: Here we report the clinical, laboratory and radiological 
characteristics of three returning travellers with Katayama fever. Inflammatory 
markers and coagulation status were assessed repeatedly during follow-up to 
characterise the host response to infection. Radiographic findings were 
correlated with clinical and laboratory markers.
RESULTS: Clinical symptoms were suggestive of a significant inflammatory 
response in all patients including high fever (>39°C), cough, and general 
malaise. Classical inflammatory markers including blood sedimentation rate, 
C-reactive protein, and serum amyloid A were only moderately elevated. Marked 
eosinophilia (33-42% of white blood cells) was observed and persisted despite 
anti-inflammatory and anthelminthic treatment for up to 32 weeks. Analysis of 
blood coagulation markers indicated increased coagulability reflected by 
elevated D-dimer values (0.57-1.17 μg/ml) and high thrombin generating 
potentials (peak thrombin activity: 311-384 nM). One patient showed particularly 
high levels of microparticle-associated tissue factor activity at initial 
presentation (1.64 pg/ml). Multiple pulmonary and hepatic opacities demonstrated 
by computed tomography (CT) scanning were associated with raised inflammatory 
markers in one patient.
CONCLUSIONS: The characterisation of the inflammatory response, blood 
coagulation parameters and radiological findings in three patients adds to our 
current understanding of Katayama fever and serves as a starting point for 
further systematic investigations of the pathophysiology of this acute 
helminthic infection.