Paragonimus kellicotti Flukes in Missouri, USA

You don’t have to be a contestant on Fear Factor to eat unusual things. An investigation of 9 new cases of lung fluke infection in Missouri found that in all cases, patients had eaten raw crayfish while on rafting or camping trips and most had been drinking alcohol. Although all patients recovered after treatment, a few whose diagnosis was delayed had unnecessary procedures and serious illness. Physicians should consider lung fluke infection in patients with nonspecific cough and fever, especially patients who have recently returned from a recreational river trip. Crayfish in Missouri rivers often carry lung flukes and should not be eaten raw.

examination results were normal. Laboratory studies indicated a leukocyte count of 8,900 cells/mm 3 with 1,400 eosinophils/mm 3 (16%) and an erythrocyte sedimentation rate of 81 mm/h.
A chest radiograph showed right upper lobe consolidation with a moderate pleural effusion.
Thoracentesis was performed and pleural fluid analysis showed orange fluid with 16,900 total cells, and 10,900 leukocytes with 66% eosinophils. The pleural fluid lactate dehydrogenase level was 2,153 IU/L and the albumin level was 3.3 mg/dL. The serum lactate dehydrogenase level was 148 IU/L and the serum protein level was 7.7 g/dL. A transthoracic echocardiogram confirmed the pericardial effusion. The patient was treated with intravenous vancomycin and cefepime. A purified protein derivative (PPD) skin test result was negative. Additional history showed that he had consumed 2 raw crayfish on a dare during a float trip on the Huzzah River in Missouri in early June 2009. His symptom onset with abdominal and shoulder pain began 3 weeks after crayfish ingestion.
A clinical diagnosis of paragonimiasis was made and antimicrobial drug therapy was discontinued. The patient was treated with oral praziquantel (25 mg/kg, 3×/d 2 days). Within 24 h, he showed had defervescence and his other symptoms improved. Sputum, fecal, and pleural fluid samples were negative for ova and parasites. Results of a P. westermani immunoblot performed at the Centers for Disease Control and Prevention (CDC) were negative. At follow-up 8 weeks after treatment, complete and differential blood counts were within reference ranges. A paragonimus enzyme immunoassay (Parasitic Disease Consultants, Tucker, GA, USA) showed a titer of 8, which was less than the threshold of 32 for positivity. A Western blot result with P. kellicotti fluke antigen performed at Washington University was positive (2). A repeat chest radiograph 8 weeks after treatment showed a residual, small, right-sided pleural effusion.

Patient 5
Patient 5 was a 10-year-old boy who came to his primary care physician with a 3-week history of fever, cough, and chest pain. He was treated with oseltamivir and amoxicillin for presumed influenza and bacterial superinfection. His symptoms improved, and he returned to his regular activities. However, during football practice, he sustained blunt chest trauma after which chest pain and fever returned. He was treated again with amoxicillin with no improvement, and he was referred to a local hospital for imaging. On further questioning, it was learned that the patient's uncle, an outdoor survivalist, had taught the patient to eat raw crayfish 1 year before the onset of his symptoms. Approximately 3 months before onset of his illness, the boy demonstrated his survival skills to his cousins during a family outing on the Current River in southeastern Missouri by ingesting a raw crayfish. On the basis of this history and his clinical manifestations, he was treated with praziquantel (25 mg/kg, 3×/d for 2 days) for a presumptive diagnosis of paragonimiasis. His chest pain and other symptoms promptly improved and he was discharged. At a follow-up clinic visit 1 month after treatment, his symptoms, eosinophilia, and effusions had resolved. A paragonimus immunoblot on acute-phase and convalescent-phase serum samples was performed at CDC and results were negative. However, results of a Western blot with P. kellicotti fluke antigen at Washington University were positive (2).

Patient 6
Patient 6 was a 20-year-old man with no medical history who came for medical care with a 2-week history of fever, diarrhea, and night sweats in September 2009. He was evaluated by his primary care physician who prescribed azithromycin for acute gastroenteritis. Routine stool cultures at that time were negative. Dyspnea and anorexia developed, and a 10-lb weight loss prompted return to his primary care physician in early November 2009. A chest radiograph at that time showed moderate bilateral pleural effusions.
Page 4 of 9 The patient was admitted to a hospital. His absolute eosinophil count was 1,300 cells/mm 3 , and a CT scan of the chest showed moderate bilateral pleural effusions and a small pericardial effusion. Transthoracic echocardiography showed a pericardial effusion with cardiac tamponade. Pericardiocentesis were performed with placement of pericardial drain Pericardial fluid had a leukocyte count of 60,800 cells/mm 3 with 50% eosinophils. Thoracentesis of a left pleural effusion yielded 1,200 mL of yellow-green fluid with a leukocyte count of 1,952 cells/mm 3 (55% eosinophils), a protein level of 6.6 g/dL (serum protein 8.0 g/dL), a lactate dehydrogenase level of 2,295 IU/L, a glucose level <5 mg/dL, and negative cytologic and routine microbiological result. After these procedures, the patient's dyspnea improved, and the pericardial drain was removed after several days. Prednisone (60 mg/day) was given empirically, and the patient was discharged shortly thereafter.
Over the next 3 months, peripheral eosinophilia and pleural effusions recurred coincident with tapering of corticosteroids, prompting 2 thoracenteses, both of which showed lymphocytic exudates. Corticosteroids had been discontinued in January 2009, one month before the patient's first visit to the pulmonary clinic at our institution. He reported persistent, low-grade exertional dyspnea and cough with sputum. Upon detailed questioning regarding travel history and exposures, the patient reported eating raw bratwurst during a camping trip 9 months earlier. Vital signs were normal, and physical examination showed decreased breath sounds and tactile fremitus with dullness to percussion at both lung bases. The absolute eosinophil count was 2,200 cells/mm 3 , the IgE level was 259 IU/mL, stool ova and parasite examination results were negative, and a PPD skin test result was negative. Serum was sent to CDC for serologic analysis, and a chest radiograph showed a small left pleural effusion. The patient was unable to provide a sputum sample.
Several weeks later, results for a Strongyloides indirect hemagglutination assay performed at CDC were positive (7.29 U/mL, reference value <1.7 U/mL). Ivermectin was prescribed; 2 doses of 0.2 mg/kg were to be taken 2 weeks apart. Subsequently, a paragonimiasis immunoblot performed at the CDC showed positive results. A Western blot with P. kellicotti fluke antigen performed at Washington University showed positive results (2). Praziquantel (25 mg/kg, 3×/d 2 days) was prescribed. After discussing the test results with the patient, he disclosed that acting on a dare from the younger members of his party, he and several other Page 5 of 9 friends had eaten raw crayfish while intoxicated during the float trip on the Jacks Fork River in June 2009, nine months before the time of diagnosis and 12 weeks before the onset of symptoms.
At a follow-up visit 1 month after treatment with praziquantel, the patient was asymptomatic. The absolute eosinophil count was 900 cells/mm 3 , and a chest radiograph showed a small, residual, left pleural effusion. Patient 8 was a healthy 30-year-old man who in July 2010 had a 2-week history of fever <38.9°C, night sweats, right-sided chest pain, productive cough with brown sputum and watery diarrhea. He was seen by his primary care physician and given a diagnosis of communityacquired pneumonia after a chest radiograph showed a right lung infiltrate and right-sided pleural effusion. He was treated with levofloxacin and corticosteroids for 10 days. The cough and dyspnea improved after treatment with prednisone. However, when the prednisone was discontinued, dyspnea returned and the patient noted a 10-lb weight loss. The patient showed no improvement in symptoms after 8 weeks of therapy with fluconazole. In addition, he had lost >20 lbs. Biopsy specimen slides were reviewed at the Armed Forces Institute of Pathology (Washington, DC, USA). Analysis did not confirm the presence of fungal elements. Additional information regarding exposures was obtained from the patient. The patient indicated that he had eaten crayfish while camping at least once a year for the past 20 years. However, he recalled consuming poorly cooked or raw crayfish while intoxicated on a camping trip 3 months before he initially sought care for dyspnea in 2008. A Western blot with P. kellicotti fluke antigen at Washington University showed a positive result (2). A paragonimus immunoblot performed at CDC also showed a positive result.
The patient was treated with praziquantel (25 mg/kg, 3×/d for 2 days). At the 6-month follow-up, chest radiograph showed resolution of pleural effusions. The patient had gained 25 lbs, but still had some residual shortness of breath. An immunoblot performed at CDC at the 60month follow-showed positive results. A complete blood count was within reference limits and showed no eosinophilia. At the 1-year follow-up, repeat imaging showed no recurrence of pleural effusion. The eosinophil count remained within reference limits. The patient continued to have dyspnea attributed to underlying chronic obstructive pulmonary disease.