Acute Schistosomiasis in Nonimmune Travelers: Chest CT Findings in 10 Patients

Abstract

Despite the absence of pulmonary symptoms in four individuals, all patients had parenchymal abnormalities. Small pulmonary nodules were the most common finding, identified in nine patients. These nodules ranged in size from 2 to 5 mm in five patients, with larger nodules ranging up to 15 mm seen in four patients. In one patient, the only parenchymal abnormality was a single 5-mm focus of ground-glass attenuation. No relationship was seen between either the presence of pulmonary symptoms or the presence of peripheral eosinophilia and the severity of parenchymal disease. No additional significant findings were identified.

Fever and eosinophilia in a returned traveller

“…Stool studies and serology are often negative at this stage. Thoracic and hepatic imaging may show multiple disseminated micronodular lesions, hypoechogenic on ultrasonography or hypodense on CT as in our case 3 – 6. This stage corresponds to the migration of the parasite (schistosomulae) first to the pulmonary capillaries, then to systemic circulation and portal system in the liver, where they mature into adults.…”

Role of imaging in the diagnosis and management of parasitic infections

“…The organisms enter systemic veins and migrate to the lungs and can cause an acute infection known as Katayama fever, which may last from 4 to 6 weeks. Symptoms of Katayama fever include fever, chills, dyspnea, dry cough, fatigue and diarrhea, or abdominal pain [29][30][31]. Peripheral eosinophilia is usually present and is a key distinguishing factor from influenza, for which the symptoms are most commonly confused.…”

“…Peripheral eosinophilia is usually present and is a key distinguishing factor from influenza, for which the symptoms are most commonly confused. Symptomatic acute infection is most common in nonimmune travelers to endemic areas, and the incidence has increased with popularity of ecotourism and adventure travel [30][31][32]. Chronic infection results from organism migration to either the mesenteric (Schistosoma mansoni and Schistosoma japonicum) or the urinary bladder venous plexi (Schistosoma hematobium).…”

“…The most common thoracic imaging finding in acute schistosomiasis infection is small nodules (2-15 mm in diameter) in a hematogenous, peripheral distribution, and may be present even if patients are asymptomatic [8,31,34]. Ground glass halos can be seen, which are nonspecific but thought to represent eosinophilic infiltration or immune complex deposition.…”

“…Ground glass halos can be seen, which are nonspecific but thought to represent eosinophilic infiltration or immune complex deposition. Other acute findings include patchy consolidation and micronodules [31,34].…”