Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 35-16: Paragonimiasis + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Most persons are asymptomatic In symptomatic cases, abdominal pain and diarrhea develop 2 days to 2 weeks after infection Chronic infection produces pulmonary symptoms and chest pain CNS disease presents with seizures, headaches, focal neurologic findings, intracerebral lesions +++ General Considerations ++ Of the eight species of Paragonimus lung flukes that cause human disease, Paragonimus westermani is the most important Eggs are released into fresh water, where parasites infect snails, and then cercariae infect crabs and crayfish Human infection follows consumption of raw, undercooked, or pickled freshwater shellfish Metacercariae then excyst, penetrate into the peritoneum and pass into the lungs, where they mature into adult worms over about 2 months +++ Demographics ++ Paragonimus species are endemic in East Asia, Oceania, West Africa, and South America, where millions of persons are infected Infections from Paragonimus kellicotti have occurred in North America, albeit rarely + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Most persons have moderate worm burdens and are asymptomatic In symptomatic cases, Abdominal pain and diarrhea develop 2 days to 2 weeks after infection Then, fever, cough, chest pain, urticaria, and eosinophilia develop Acute symptoms may last for several weeks Chronic infection can cause Cough productive of brown sputum Hemoptysis Dyspnea Chest pain Ectopic infections can cause disease in other organs, most commonly the CNS CNS disease can present with Seizures Headaches Focal neurologic findings due to parasite meningitis Intracerebral lesions +++ Differential Diagnosis ++ Tuberculosis Mycoplasma pneumoniae infection Bacterial pneumonia Legionnaires disease (Legionella) Amebic lung abscess + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Diagnosis is made by identifying Characteristic eggs in sputum or stool or Worms in biopsied tissue Multiple examinations and concentration techniques may be needed Serologic tests may be helpful An enzyme-linked immunosorbent assay (ELISA) available from the CDC has sensitivity and specificity > 95% +++ Imaging Studies ++ Chest radiographs may show Infiltrates Nodules Cavitary lesions Fibrosis Skull radiographs can show clusters of calcified cysts CT or MRI can show clusters of ring-enhancing lesions + Treatment Download Section PDF Listen +++ +++ Medications ++ Praziquantel Drug of choice 25 mg/kg orally three times daily for 2 days Use with corticosteroids for cerebral paragonimiasis Bithionol and triclabendazole are alternative therapies + Outcome Download Section PDF Listen +++ +++ Complications ++ Bronchitis Bronchiectasis Bronchopneumonia Lung abscess Pleural thickening or effusion +++ Prognosis ++ Cure rates of over 90% can be anticipated for praziquantel +++ When to Refer ++ All patients should be referred to a clinician with expertise in the diagnosis and management of this disease +++ When to Admit ++ Patients with presumed or confirmed CNS infection + Reference Download Section PDF Listen +++ + +Blair D. Paragonimiasis. Adv Exp Med Biol. 2019;1154:105–38. [PubMed: 31297761]