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

• Capillaria Infection

What is 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 that involves the liver and is caused by consuming contaminated food and water. The pathogen responsible for the infection is called Capillaria hepatica
  • Intestinal Capillariasis that involves the small intestine and is caused by consuming infected freshwater fish. The pathogen responsible for the infection is Capillaria philippinensis
  • Pulmonary Capillariasis that affects the lungs and airways and is caused by ingestion of feces or salivary secretions of infected dogs and cats (mostly). The pathogen responsible for the infection is Capillaria aerophila
• Depending on the type of Capillariasis, the associated signs and symptoms are observed. Hepatic Capillariasis results in fever, anemia, and hepatitis; Intestinal Capillariasis results in diarrhea and malabsorption syndrome; and, Pulmonary Capillariasis can lead to runny nose, blood in sputum, and breathing difficulties
• All three forms of Capillariasis are rare but found sporadically across the world. The infection may affect individuals of any age, gender, or race and ethnicity. Factors, such as poor hygiene and lack of adequate sanitation facilities, play a role in its development and spread
• Analysis of stool samples, study of nasal discharge, and/or a tissue biopsy can help diagnose the type of Capillariasis. Following a diagnosis, the infection is treated by administering suitable antiparasitic medications. With suitable treatment, the prognosis is good in a vast majority of the individuals
• Pulmonary Capillariasis is usually mild and does not cause any complications. Hepatic Capillariasis may present liver dysfunction and liver failure in the absence of adequate treatment; while, Intestinal Capillariasis can even be fatal due to severe weakness and heart function abnormalities

Who gets Capillariasis? (Age and Sex Distribution)

• Individuals of any age group and both male and female gender are susceptible to developing Capillariasis. It is important to note that globally only a few numbers of cases have been documented
• In the endemic regions, no racial or ethnic predilection is reported in the development of this infection. The worldwide distribution varies according to the type of infection
• Hepatic Capillariasis is reported from both tropical and temperate regions of the world; Intestinal Capillariasis is mostly observed in Philippines and Thailand; while, Pulmonary Capillariasis is generally reported from Europe and North America

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

The following are the risk factors for Capillariasis: 

• Hepatic Capillariasis:
  • Eating unwashed fruits or vegetables
  • Eating the liver of wild animals
  • Individuals with pica
• Intestinal Capillariasis
  • Consuming infected raw or uncooked freshwater fish
  • Poor sanitation and toilet facilities
• Pulmonary Capillariasis
  • Exposure to infected animal feces or sputum
  • Consuming raw fruits and vegetables without washing them

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 Capillariasis? (Etiology)

Capillariasis is a zoonotic infection that rarely affects humans; humans become inadvertent hosts of the parasitic nematodes (roundworms), which belong to any of the Capillaria subspecies, mostly through the consumption of contaminated food.

• Hepatic Capillariasis is caused by Capillaria hepatica, on consuming food products that are grown on contaminated soil (contaminated by feces of infected animals such as rats, foxes, or dogs)
• Intestinal Capillariasis is caused by Capillaria philippinensis, on ingestion of infected freshwater fish in the endemic regions
• Pulmonary Capillariasis is caused by Capillaria aerophila, on direct exposure to the infected animal’s sputum or feces; or, on the consumption of raw fruits and vegetables tainted with contaminated soil (contaminated by feces of infected animals such as foxes, dogs, or cats)

What are the Signs and Symptoms of Capillariasis?

The signs and symptoms of Capillariasis may vary from one individual to another and primarily depends on the subtype of infection. In some, it may be mild; while in others, it may be severe. 

The signs and symptoms of Hepatic Capillariasis may include:

• Fever
• Anemia
• Enlargement of the liver
• Hepatitis

The signs and symptoms of Intestinal Capillariasis may include:

• Abdominal pain
• Watery diarrhea
• Vomiting
• Malabsorption that may be severe
• Loss of weight

The signs and symptoms of Pulmonary Capillariasis are mostly mild and may include:

• Coughing
• Running nose
• Fever
• Shortness of breath (rarely)
• Blood in sputum

Eosinophilia: Increased eosinophil count due to infection may be noted in all of the above subtypes. Eosinophils are a type of white blood cells (WBCs) that the body uses to fight infections and parasites.

How is Capillariasis Diagnosed?

The diagnosis of Capillariasis is specific to the type of Capillariasis but may generally involve the following tests and exams:

• 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
  • Pulmonary function test
• Ova and parasites stool test; microscopic examination of stool sample
• Examination of nasal washings or tracheal lavage
• Imaging scans of the abdomen or chest
• Fine needle aspiration (FNA) biopsy of the affected region
• Tissue 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 Capillariasis?

The complications of Capillariasis that develop usually in the absence of adequate treatment may include:

• Hepatic Capillariasis complications:
  • Liver dysfunction
  • Liver failure
• Intestinal Capillariasis complications:
  • Severe and chronic malabsorption
  • Muscle wasting and emaciation
  • Heart associated abnormalities
• Pulmonary Capillariasis complications:
  • Acute bronchitis
  • Pneumonia from secondary bacterial infections
• In some individuals, the burden of infection can be huge, resulting in large volume of parasitic infestation. This results in a condition called hyperinfection (repeat infection by host larvae present in the body)

How is Capillariasis Treated?

The treatment measures for Capillariasis includes the following: 

• Anthelmintic therapy: Administration of anti-parasitic medications to help kill the parasite
• Hospitalization and supportive therapy, including compensating for water and mineral loss via intravenous fluid administration, respiratory support, etc.
• Providing treatment for any underlying condition

How can Capillariasis be Prevented?

Some of the preventative measures for Capillariasis may include:

• Avoiding eating raw or uncooked (freshwater) fish, especially in the endemic areas
• Washing any fruits or vegetables before consumption, to ensure that they are free of dirt and soil
• Avoiding the consumption of wild animals; else, cooking any wild animal thoroughly before consumption
• Washing hands with warm water and soap after working with or touching soil, especially before handling food
• Train children to understand the importance of washing their hands, especially after playing in the mud, or after playing outdoors
• Be careful while handling pet cat or dog feces
• Practicing good hygiene and disposing of fecal matter properly

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

The prognosis of 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, Hepatic Capillariasis can lead to severe hepatitis and liver failure, resulting in fatalities
• In the absence of appropriate treatment, Intestinal Capillariasis can cause severe complications and result in fatalities due to cardiomyopathy. It is among the most severe form of Capillariasis
• In the absence of appropriate treatment, Pulmonary Capillariasis can cause severe complications, although it is rare

Additional and Relevant Useful Information for Capillariasis:

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

https://www.dovemed.com/diseases-conditions/infection-center/