What are the other Names for this Condition? (Also known as/Synonyms)

• Capillaria Infection of Intestines
• Human Intestinal Capillariasis
• Infection by Capillaria Philippinensis

What is Intestinal Capillariasis? (Definition/Background Information)

• Capillariasis or Capillaria infection is caused by certain parasitic organisms, called nematodes or roundworms, belonging to the genus Capillaria. Three forms of Capillaria infection have been identified based on the causative subspecies. These include:
  • Hepatic capillariasis or Capillaria hepatica Infection
  • Intestinal Capillariasis or Capillaria Philippinensis Infection
  • Pulmonary capillariasis or Capillaria aerophila infection
• Intestinal Capillariasis is an infection of the intestine, especially the small intestine, caused by the nematode Capillaria philippinensis. The condition mostly causes diarrhea and malabsorption syndrome, when the absorption of nutrients is hindered in the small intestine, leading to severe enteropathy (intestinal disease)
• It is reportedly common in the endemic regions, particularly in Philippines and Thailand, among people who consume freshwater fish without cooking. Ingestion of infected fish leads to intestinal infection by the parasitic larva causing associated symptoms that may be life-threatening without treatment
• Analysis of stool samples and intestinal tissue through a biopsy can help diagnose Intestinal Capillariasis. Following a diagnosis, the infection is treated by administering suitable antiparasitic medications. With adequate treatment, the affected individuals are known to make a full recovery and the outcomes are good

Who gets Intestinal Capillariasis? (Age and Sex Distribution)

• Intestinal Capillariasis is mostly reported from Philippines and Thailand. It is common in some of the endemic regions
• Other regions from where the infection is reported include the Middle East (Iran, Egypt, and United Arab Emirates) and parts of Asia (China, Taiwan, Japan, Korea, Indonesia, and India). Sporadic episodes have been reported from countries such as Colombia, Italy and Spain
• Individuals of any age group and both male and female gender are susceptible to developing the infection
• In the endemic regions, no racial or ethnic predilection is reported in the development of this infection

What are the Risk Factors for Intestinal Capillariasis? (Predisposing Factors)

The following are some risk factors for Intestinal Capillariasis: 

• Consuming infected raw or improperly cooked freshwater fish in the endemic regions; some of the local populations are known to follow this practice in the endemic areas (as part of their culture)
• Contamination of waterbodies by the feces of humans, animals, and birds that feed on the fish; such contaminated water can cause ‘new’ infection in the fish
• Poor sanitation and toilet facilities

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Intestinal Capillariasis? (Etiology)

Intestinal Capillariasis is caused by infection with nematodes belonging to the species Capillaria philippinensis, a parasitic roundworm. The infection develops after humans ingest infected freshwater fish in the endemic regions. The involvement of several species of small freshwater fish have been suspected.

• When humans consume raw or uncooked infected fish (particularly whole fish), the larval forms of the parasite infect the human intestines
• The larva grows and becomes adult worms which are subsequently released as eggs in the feces of infected humans (or animals). When the feces contaminate the natural freshwater sources, it causes infection in the freshwater fish, leading to the production of larvae
• This creates a cycle of infection and reinfection between fish and humans. Humans help in the life cycle of the parasite inadvertently, while the fish serve as intermediate hosts
• However, the probable primary hosts for C. philippinensis are fish-eating birds, such as herons, waterhens, egrets, and bitterns, and mammals, such as monkeys and gerbils, which are known to feed on the infected fish
• When such infected animals and birds release their feces containing embryonated eggs of the parasite into freshwater, to be consumed by the freshwater fish, the cycle is complete

It is not possible for the Capillaria Philippinensis Infection to be transmitted from one human being to another human being.

What are the Signs and Symptoms of Intestinal Capillariasis?

The gastrointestinal system is affected, chiefly the small intestine, and hence, a majority of the signs and symptoms of Intestinal Capillariasis are related to diarrhea that is progressive in nature, and malabsorption.

In general, the signs and symptoms of Intestinal Capillariasis include:

• Abdominal pain
• Rumbling sound of fluid and gas in the intestines (termed borborygmus)
• Progressive diarrhea, usually watery diarrhea
• Vomiting
• Malabsorption that may be severe
• Loss of weight
• Weakness and fatigue
• Abdominal distention (swollen abdomen)
• Fever is not usually noted
• Eosinophilia: Increased eosinophil count due to infection is rarely noted. Eosinophils are a type of white blood cells (WBCs) that the body uses to fight infections and parasites

How is Intestinal Capillariasis Diagnosed?

The diagnosis of Intestinal Capillariasis is made through:

• A complete physical examination and review of one’s medical and/or recent travel history
• Assessment of the presenting signs and symptoms
• Blood tests that may include:
  • Complete blood count (CBC)
  • Liver function test
• Ova and parasites stool test; microscopic examination of stool sample is helpful in identifying the parasite
• Imaging scans of the abdomen
• Fine needle aspiration (FNA) biopsy of the small intestine: A smaller number of intestinal cells are taken to be analyzed in the lab
• Small intestinal biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Intestinal Capillariasis?

The complications of Intestinal Capillariasis which may develop, usually in the absence of adequate treatment, may include:

• Chronic malabsorption can cause mineral, vitamin, and electrolyte loss from the body; the condition causes hypokalemia (low levels of potassium in blood)
• Muscle wasting and severe debilitation
• Weak heart and cardiac insufficiency
• In some individuals, the burden of infection can be huge, resulting in large volume of adult worms in the intestines. This results in a condition called hyperinfection due to Capillaria philippinensis (repeat infection by host larvae present in the body)
• Such a hyperinfection of C. philippinensis can lead to weakness and malnutrition, called emaciation

Severe complications can even result in death without adequate treatment. Protein-losing enteropathy can result in severe weight loss and heart failure leading to emaciation and death.

How is Intestinal Capillariasis Treated?

The treatment measures for Intestinal Capillariasis includes the following: 

• Anthelmintic therapy: Administration of anti-parasitic medications, such as mebendazole or albendazole, to help kill the parasite
• Hospitalization and supportive therapy, including compensating for water and mineral loss via intravenous fluid administration

How can Intestinal Capillariasis be Prevented?

The preventative measures for Intestinal Capillariasis may include:

• Avoiding eating raw or uncooked (freshwater) fish, especially in the endemic areas
• Practicing good hygiene and disposing of fecal matter properly
• Washing hands with warm water and soap after working with or touching soil, especially before handling food

The following US FDA guidelines may be considered towards the fish storage and cooking practices, in order to eliminate any parasitic infections:

• Storage by freezing:
  • For a period of 24 hours; storage should be at temperatures of -31°F (-35°C) or lower, till fish is frozen solid, and then maintained at -4°F (-20°C) or lower temperatures
  • For a period of 15 hours; storage should be at temperatures of -31°F (-35°C) or lower, till fish is frozen solid, and then maintained at the same or lower temperatures
  • For a period of 7 days; storage should be at -4°F (-20°C) or lower temperatures
• Cooking: Fish should be cooked to internal temperatures of or above 145°F (63°C)

What is the Prognosis of Intestinal Capillariasis? (Outcomes/Resolutions)

• The prognosis of Intestinal Capillariasis is generally excellent with appropriate treatment (use of antiparasitic medications)
• Individuals usually recover completely with early diagnosis and adequate treatment. In case of any relapses, the treatment may be prolonged
• In the absence of appropriate treatment, the infection can cause severe complications and result in fatalities due to cardiomyopathy in over 30% of the cases, according to documented reports

Additional and Relevant Useful Information for Intestinal Capillariasis:

Please visit our Digestive Health Center for more physician-approved health information:

https://www.dovemed.com/healthy-living/digestive-center/