Opisthorchiasis

Opisthorchiasis causes arthralgia, lymphadenopathy, and rash. Chronically, it causes jaundice, cholangitis, and cholangiocarcinoma. Snails are first and fish second intermediate hosts for these trematodes. Humans are infected after eating undercooked, salted, pickled, or smoked freshwater fish.

CASES/YEAR
0 (US); 11,200,000 (Global)
CATEGORY
AGENT TYPE
Helminths
OTHER NAMES
Opisthorchis viverrini (Southeast Asian liver fluke); O. felineus (cat liver fluke); Liver flukes (Opisthorchiasis)
ACUITY
Subacute/Chronic
INCUBATION
1 month after ingestion of encysted larvae for flukes to reach maturity; [CCDM]
INITIAL SYMPTOMS
Acute: fever, arthralgia, lymphadenopathy, and rash; Chronic: jaundice, cholangitis, and cholangiocarcinoma; [Cecil, p. 2125]
PRECAUTIONS
"Infected individuals may pass viable eggs for as long as 30 years; infection is not directly transmitted from person to person." [CCDM, p. 359]
COMMENTS
Snails are the first and fish the second intermediate hosts for these trematode infections. Humans become infected after eating undercooked, salted, pickled, or smoked freshwater fish. Flukes mature and lay eggs in the biliary ducts. Patients with acute infections are usually asymptomatic. Some patients have an acute illness with fever, fatigue, abdominal pain, eosinophilia, arthralgia, and hepatomegaly. Patients with chronic infections may have hepatomegaly and malnutrition. Marked eosinophilia is present early and may or may not be present during chronic infection. Complications of chronic infection include obstructive jaundice, cholangitis, pancreatitis, cirrhosis, and cholangiocarcinoma. Reservoirs include humans, cats, dogs, swine, and rats. [Guerrant, p. 943, 854-8; CCDM, p. 358-60; http://www.dpd.cdc.gov/dpdx/] Patients with chronic disease may have episodes of cholangitis with bacterial sepsis. "Serologic tests, antigen detection tests, and PCR-based assays are not widely available outside endemic areas or research laboratories." [PPID, p. 3459]
DIAGNOSTIC
Microscopic identification of eggs in stool or duodenal aspirates; Detect characteristic cystic changes in the liver with ultrasound, MRI, or CT; Identify flukes in gallbladder at surgery or with M-mode ultrasonography; [PPID, p. 3459]
SCOPE
O. felineus in E. Europe, SE Asia and Siberia; O. viverrini in Thailand, W. Malaysia, and Laos; [ID, p. 2381]
SIGNS & SYMPTOMS
  • >arthralgia
  • >fatigue, weakness
  • >fever
  • G abdominal pain
  • G diarrhea
  • G hepatomegaly
  • G jaundice
  • G liver function test, abnormal
  • G nausea, vomiting
  • H eosinophilia
  • H leukocytosis
  • H lymphadenopathy
  • S rash (exanthem)
  • S urticaria
  • *cancer
  • *cirrhosis
  • *hepatitis
  • *pancreatitis
  • *sepsis
  • *weight loss
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Ingestion
SOURCE
Animal Tissue, Eating Contaminated Food, Eating Infected or Toxin-Containing Fish
RESERVOIR
Dogs, Fish and Shellfish, Rodents, Swine, Human
RISK FACTORS
  • Eat undercooked meat or fish
  • Travel to endemic area
TREATMENT
Praziquantel is the drug of choice. [CCDM, p. 138]
REFERENCES FOR CASES/YEAR
1.
2. (Global) 56 million suffered and 7000 died from foodborne trematodiases in 2005; [Fact sheets from WHO] About 10 million infected with O. viverrini and about 1 million infected with O. felineus; [CCDM] 11.2 million people infected (8 million in Thailand and 2 million in Laos); [Cecil, p. 2126]