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

• Bronchial Capillariasis
• Infection by Capillaria Aerophila
• Thominxosis

What is Pulmonary 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
• Pulmonary Capillariasis is an infection of the lungs and airways caused by the nematode Capillaria aerophila (also known as Thominx aerophilum in some literature). The condition is usually mild and can cause runny nose, blood in sputum, and breathing difficulties. Infrequently, it may result in pneumonia
• Mammals, such as foxes, dogs, and cats, including pets, are natural hosts for the parasite. Sometimes, ingestion of the infected feces or salivary secretions of such animals by humans result in Pulmonary Capillariasis
• Analysis of stool samples and nasal discharges can help diagnose the infection. Following a diagnosis of Pulmonary Capillariasis, it 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 Pulmonary Capillariasis? (Age and Sex Distribution)

• Pulmonary Capillariasis is generally reported from Europe and North America. Some cases have been recorded in Australia and New Zealand, Asia, Russia, and South America
• However, the condition is extremely rare in humans. It is difficult to estimate the actual incidence of Pulmonary Capillariasis, since many individuals may not have clinical signs and symptoms resulting in an underdiagnosis
• Individuals of any age group and both male and female gender are susceptible to developing the infection
• No racial or ethnic predilection is reported in the development of this infection

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

The following are some risk factors for Pulmonary Capillariasis: 

• Direct exposure to infected dog, cat, or certain wild animals’ feces, or to soil contaminated by their feces
• Exposure to salivary secretions or sputum of infected pets such as dogs and cats
• Consuming unwashed or uncleaned raw fruits and vegetables tainted with contaminated soil
• Rarely, exposure to sputum or feces of infected humans
• Drinking untreated water from a stream or a well, or from any such source that is contaminated
• Poor sanitation and toilet facilities
• Not washing hands prior to eating, after going to toilet, etc.

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 Pulmonary Capillariasis? (Etiology)

Pulmonary Capillariasis is caused by infection with nematodes belonging to the species Capillaria aerophila, a parasitic roundworm.

• The parasite occurs worldwide and can be seen in variety of wild and domesticated animals including dogs, cats, foxes, coyotes, racoons, etc. Usually there are no significant symptoms noted in the infected dogs and cats
• When humans ingest contaminated eggs that are contained in the infected animal’s sputum or feces, the eggs develop into larval forms in the intestine
• These larval forms then migrate to the lungs, where they develop into adults. The adult worms lay eggs in the lungs, causing associated signs and symptoms. These are then coughed up and get swallowed by the infected individual
• These swallowed eggs are passed on through the feces to contaminate the soil; the ova mature in moist soil. When a human consumes food (fruits or vegetables) containing eggs from the contaminated soil, the infect life cycle continues
• Humans help in the life cycle of the parasite inadvertently, while the wild and domesticated carnivores (mostly foxes, dogs, and cats) serve as the primary hosts for the parasite

In very rare cases, Capillaria Aerophila Infection may be directly transmitted from one human being to another human being.

What are the Signs and Symptoms of Pulmonary Capillariasis?

The respiratory system, chiefly the lungs and airways, is affected. The signs and symptoms of Pulmonary Capillariasis are generally minor and may include:

• Coughing
• Mild irritation to the airways causing running nose
• Fever
• Shortness of breath (rarely)
• Blood in sputum
• Episodes of asthma
• Eosinophilia: Mildly increased eosinophil count due to infection is noted. Eosinophils are a type of white blood cells (WBCs) that the body uses to fight infections and parasites

How is Pulmonary Capillariasis Diagnosed?

The diagnosis of Pulmonary Capillariasis is made through:

• A complete physical examination and review of one’s medical history
• Assessment of the presenting signs and symptoms
• Blood tests that may include:
  • Complete blood count (CBC)
  • Pulmonary function test
• Examination of nasal washings or tracheal lavage may reveal eggs of C. aerophila
• Ova and parasites stool test; microscopic examination of stool sample may also reveal eggs
• Imaging scans of the chest and lungs

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 Pulmonary Capillariasis?

The complications of Pulmonary Capillariasis are rare but may develop in the absence of adequate treatment. The complications may include:

• Acute bronchitis
• Secondary or opportunistic bacterial infection can occur in the lungs causing pneumonia
• Respiratory distress
• Occasionally, an increased number of parasitic organisms in the lungs can cause hyperinfection due to Capillaria aerophila (repeat infection by host larvae present in the body)

How is Pulmonary Capillariasis Treated?

The treatment measures for Pulmonary Capillariasis includes the following: 

• Anthelmintic therapy: Administration of broad spectrum anti-parasitic medications, such as ivermectin, fenbendazole or levamisole, to help kill the parasite
• Course of antibiotics to treat secondary bacterial infections, if any
• Occasionally, hospitalization and supportive therapy, including breathing support and intravenous fluid administration, as needed

How can Pulmonary Capillariasis be Prevented?

The preventative measures for Pulmonary Capillariasis may include:

• Fruits and vegetables have to be washed and cleaned well, particularly if they are to be consumed raw
• Cover nose and mouth while coughing or sneezing
• Practicing good hygiene and disposing of fecal matter properly
• Avoid undercooked food and contaminated water; always drink water that is clean and from a reliable source
• 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
• Garden soil may be contaminated with Capillaria aerophila found in animal feces - wash hands thoroughly with soap and warm water after being in contact with the soil (especially after activities such as gardening or backyard cleaning)
• Exposure to direct sunlight is known to minimize infection spread in animal shelters and pens
• Individuals that belong to certain high-risk groups, such as working at a vet clinic, a pet store, or having a weak immune system, are required to ensure that adequate safety precautions are taken while handling pet cats and dogs

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

• The prognosis of Pulmonary 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 rarely cause severe complications

Additional and Relevant Useful Information for Pulmonary Capillariasis:

Please visit our Healthy Lungs Center for more physician-approved health information:

https://www.dovemed.com/healthy-living/healthy-lungs/