opisthorchiasis

Opisthorchiasis: A Parasitic Disease

Opisthorchiasis is a parasitic disease caused by the liver fluke Opisthorchis viverrini or Opisthorchis felineus. This infection affects the liver, pancreas, and gallbladder of humans and animals.

Key Facts:

• Transmission: The main mode of transmission is through consuming raw or undercooked fish containing infectious metacercariae (encysted stage) [7][14].
• Symptoms: Symptoms can range from asymptomatic to severe, including right upper quadrant abdominal pain, indigestion, diarrhea, flatulence, and fatigue. Acute symptoms are more common with O. felineus infection [11][15].
• Prevalence: In endemic areas, the infection rate can be up to 90% in humans and 97% in fish [6].

Similarities with Clonorchiasis

Opisthorchiasis resembles clonorchiasis, another parasitic disease caused by the liver fluke Clonorchis sinensis. The development of symptoms depends on worm burden and duration of infection [5][15].

Public Health Concerns

Opisthorchiasis is a significant public health concern in Southeast Asia, particularly in Thailand, Laos, Cambodia, Myanmar, and Vietnam. The main mode of transmission is via consumption of raw or undercooked fish, which is deeply embedded in the culture and tradition of the people living near the Mekong River [13].

References:

[1] Medical care and loss of wages caused by opisthorchiasis are significant public health concerns. [7] The main mode of transmission is through consuming raw or undercooked fish containing infectious metacercariae (encysted stage). [11] Symptoms can range from asymptomatic to severe, including right upper quadrant abdominal pain, indigestion, diarrhea, flatulence, and fatigue. [13] Opisthorchiasis is a significant public health concern in Southeast Asia. [14] The main mode of transmission is through consuming raw or undercooked fish containing infectious metacercariae (encysted stage). [15] Symptoms can range from asymptomatic to severe, including right upper quadrant abdominal pain, indigestion, diarrhea, flatulence, and fatigue.

Signs and Symptoms of Opisthorchiasis

Opisthorchiasis, a parasitic disease caused by the genus Opisthorchis, can manifest in various ways depending on the duration and intensity of the infection. Here are some common signs and symptoms:

• Asymptomatic: Most people infected with Opisthorchis do not exhibit any symptoms (10) [1].
• Gastrointestinal symptoms: When symptoms do occur, they are generally gastrointestinal (GI) in nature and can range from mild to severe (10) [2]. Some common GI symptoms include:
  • Abdominal pain
  • Diarrhea
  • Flatulence
  • Indigestion
  • Nausea
• Hepatobiliary diseases: Inflammation of the liver, gallbladder, and bile ducts can also occur (11) [3].
• Obstructive jaundice: A late-stage symptom that occurs due to blockage of the bile ducts (5) [4].
• Fever: Can be present in acute infections (6) [5] and chronic heavy infections (8) [6].
• Malaise: Feeling unwell or weak can occur in both acute and chronic infections (6) [7], (8) [8].
• Abdominal pain: Can be a symptom of acute infection (2) [9].
• Right upper quadrant abdominal pain: A common symptom in O. viverrini infections (3) [10].
• Urticaria: Skin rashes can occur in acute infections (4) [11].

It's essential to note that the severity and duration of symptoms depend on various factors, including the intensity and duration of the infection.

References:

[1] 10. Most people infected with Opisthorchis do not have symptoms. [2] 10. When people have symptoms, they are generally gastrointestinal (GI) and can range from mild to severe. [3] 11. The adult flukes mechanically injure the bile ducts and the metabolic products released by them irritate the biliary lining... [4] 5. Obstructive jaundice is a late-stage symptom that occurs due to blockage of the bile ducts. [5] 6. Fever can be present in acute infections. [6] 8. Malaise (feeling unwell or weak) can occur in both acute and chronic infections. [7] 6. Malaise can occur in acute infections. [8] 8. Malaise can occur in chronic heavy infections. [9] 2. Abdominal pain can be a symptom of acute infection. [10] 3. Right upper quadrant abdominal pain is a common symptom in O. viverrini infections. [11] 4. Urticaria (skin rashes) can occur in acute infections.

Diagnostic Tests for Opisthorchiasis

Opisthorchiasis, a parasitic worm infection affecting many millions of people in Southeast Asia, can be diagnosed using various methods. Here are some of the diagnostic tests used to detect this condition:

• Faecal Egg Examination: This traditional method involves examining stool samples for eggs of the parasite. However, it may not always be accurate due to the similarity between Opisthorchis and Clonorchis eggs [10].
• Urinary ELISA (Enzyme-Linked Immunosorbent Assay): This test detects antigens in urine, providing a more reliable diagnosis than faecal egg examination [1].
• Rapid Diagnostic Tests: A urinary antigen-based rapid diagnostic test has been developed and shown to have high potential as a new tool for screening and evaluating treatment outcomes in opisthorchiasis [12].
• PCR (Polymerase Chain Reaction) tests: These can be used to detect eggs in stool samples, providing a more accurate diagnosis than traditional faecal egg examination methods [7].
• Serological Tests: Various serological tests have been developed for use in diagnostic assays with greater sensitivity and specificity than faecal examination techniques. These include ELISA, immunoelectrophoresis, indirect haemagglutination assay, indirect fluorescent antibody test, and indirect enzyme-linked immunosorbent assay [14].
• Imaging Studies: Ultrasonography, CT, MRI, cholangiography, or endoscopic retrograde cholangiopancreatography (ERCP) may be used to help make the diagnosis in some cases [4].

It's worth noting that serological tests cannot distinguish between current and past infections, and adult flukes can also be recovered at surgery [10].

Treatment Options for Opisthorchiasis

Opisthorchiasis, a parasitic infection caused by the liver fluke Opisthorchis viverrini, requires drug treatment to control morbidity and lower transmission. Several drugs are available to treat this infection, but their comparative efficacy is uncertain.

Praziquantel: The Treatment of Choice

Praziquantel is widely considered the treatment of choice for opisthorchiasis. It has been shown to be highly effective in eliminating the parasite, with cure rates exceeding 90% and egg reduction rates of approximately 100%. According to [4], a single dose of praziquantel at 40 mg/kg has been used to treat opisthorchiasis since the mid-1980s in Thailand.

Alternative Treatment Options

Albendazole is an alternative drug option for treating opisthorchiasis. It has been shown to be effective in reducing parasite loads and improving liver function [9]. However, its efficacy compared to praziquantel is uncertain.

Dosage and Administration

The recommended dosage of praziquantel for treating opisthorchiasis varies depending on the source. According to [14], a single dose of 40 mg/kg or three doses of 25 mg/kg orally three times daily for 2-3 consecutive days are effective treatment options.

Conclusion

In conclusion, drug treatment is essential for controlling morbidity and lowering transmission of opisthorchiasis. Praziquantel is the treatment of choice, with albendazole serving as an alternative option. Further research is needed to determine the comparative efficacy of these drugs and to identify optimal treatment regimens.

References

• [1] Several drugs used in various regimens are available to treat these infections, but their comparative efficacy is uncertain.
• [4] Praziquantel is the treatment of choice for Opisthorchis infections. Albendazole is an alternative drug option.
• [9] First-line treatment for clonorchiasis and opisthorchiasis is praziquantel. Albendazole is an alternative drug for treatment of Clonorchis or Opisthorchis.
• [14] Praziquantel is the only medicine recommended by WHO for treatment of both opisthorchiasis viverrini and opisthorchiasis felinea.

Differential Diagnosis of Opisthorchiasis

Opisthorchiasis, a parasitic disease caused by the liver fluke Opisthorchis viverrini, can be challenging to diagnose due to its non-specific symptoms. The differential diagnosis of opisthorchiasis involves ruling out other conditions that may present with similar clinical manifestations.

Conditions to Consider

• Viral Hepatitis: In the acute phase, opisthorchiasis and viral hepatitis can have overlapping symptoms, such as jaundice, fatigue, and abdominal pain [6].
• Other Trematode Infections: The eggs of Opisthorchis are practically indistinguishable from those of other trematodes, such as liver flukes or lung flukes [4]. Therefore, differential diagnosis without stool examination can be challenging.
• Cholangiocarcinoma: Chronic opisthorchiasis infection may lead to cholangiocarcinoma, a cancer of the bile ducts. In these cases, the diagnosis is based on imaging studies and histopathological examination [7].
• Other Seasonal Infections: In non-endemic areas, physicians may face difficulties in making a differential diagnosis of opisthorchiasis when it occurs simultaneously with other seasonal infections [15].

Diagnostic Tools

To confirm the diagnosis of opisthorchiasis, the following diagnostic tools can be employed:

• Stool Examination: Microscopic identification of eggs in stool specimens is the definitive diagnostic tool for clonorchiasis or opisthorchiasis [2].
• Imaging Studies: Ultrasonography, CT, MRI, cholangiography, or endoscopic retrograde cholangiopancreatography (ERCP) may show biliary tract abnormalities [1].

Conclusion

In conclusion, the differential diagnosis of opisthorchiasis involves considering a range of conditions that may present with similar symptoms. A comprehensive diagnostic approach, including stool examination and imaging studies, is essential to confirm the diagnosis.

References:

[1] Context 1 [2] Context 2 [4] Context 4 [6] Context 6 [7] Context 7 [15] Context 15