References:

  1. Global Infectious Diseases and Epidemiology Online Network: Infectious Diseases of the Philippines, 2013 eBook Edition, ISBN 978-1-61755-582-4, by Stephen Berger. Accessed here.

AgentPARASITE - Platyhelminthes, Trematoda. Paragonimus westermani, P. heterotremus, P. skrjabini, P.
miyazakii, P. africanus, et al.
ReservoirHuman
Dog
Cat
Pig
Wild carnivore
Snail (Semisulcospira, Thiara, etc.)
VectorNone
VehicleFres-water crab (at least 8 species)
Crayfish (Cambaroides)
Incubation Period6 weeks to 6 months
Diagnostic TestsIdentification of ova in sputum or stool
Serologic and skin tests are available
Typical Adult TherapyPraziquantel 25 mg/kg TID X 2d. OR Bithionol 40 mg/kg every other day X 10 doses. OR Triclabendazole 10 mg/kg/d X 2
Typical Pediatric TherapyAs for adult
Clinical HintsPulmonary infection with bloody or “rusty” sputum, central nervous system disease (eg, meningitis or seizures) and eosinophilia; subcutaneous nodules occasionally observed; parasite may survive for decades in human host.
SynonymsAlaria, Endemic hemoptysis, Lung fluke, Oriental lung fluke, Paragonimus, Poikilorchis, Pulmonary
distomiasis.

The acute phase of parasitic invasion and migration is accompanied by diarrhea, abdominal pain, fever, urticaria, hepatosplenomegaly, wheezing, cough, pleuritic pain, and eosinophilia or hypereosinophilia.

  • Later, pulmonary manifestations include cough, expectoration of discolored sputum, hemoptysis, and chest roentgenographic abnormalities.
  • Pulmonary infection may mimic lung cancer, both clinically and radiologically
  • Paragonimiasis is a common cause of persistent pleural effusion in endemic regions; such collections may suggest the diagnosis of chylothorax.
  • Extrapulmonary infection may involve the brain (less than 1% of cases), epidural space, subcutaneous tissues (most commonly the trunk and thighs), hepatobiliary system, colon or other organs.
  • Subcutaneous disease is found in 10% of patients with P. westermani infection, and 20% to 60% of those with P. skrjabini (P. szechuanensis) infection.
  • Rare instances of disseminated infection with septic shock have been reported.