Capillariasis (Capillaria Infection)
Capillariasis is an infectious disease caused by a roundworm, also known as a nematode, of the Capillaria species. The most common culprit is the Capillaria philippinensis. There have been instances of Capillaria hepatica and Capillaria aerophila causing human infections. Capilaria hepatica causes Hepatic Capillariasis while Capillaria aerophila causes Pulmonary Capillariasis.
The lifecycle of the Capillaria species begins as eggs that become embryonated after being expelled in human stool from the body. The eggs are ingested by fish that live in fresh water. Larvae then hatch from the eggs and enter the intestines of the fish. From there, the larvae migrate to the tissues of the fish. When the fish is consumed by a human raw or improperly cooked, the human becomes the new host.
Matured to adulthood, the roundworms reside in the small intestine of the human host and burrowing in the mucosa occurs. There, the female roundworms place unembryonated eggs to begin the cycle anew. Some of these eggs remain in the small intestine and hatch as larvae, causing autoinfection in the human host. This will typically result in what is known as hyperinfection, where a vast number of adult roundworms inhabit the body.
Capillaria philippinensis is found as a parasitic being in birds that eat fish. Capillaria hepatica can often be found as adult worms within rats. Capillaria aerophila can be found in a variety of animals, favoring the epithelium of the host’s tracheo bronchial tract. Eggs are expelled via coughing or swallowed and then excreted by the animal where they become embryonated in the earth.
As suggested by its name, Capillaria philippinensis infection is regularly found in the Philippines. Capillaria philippinensis is also endemic in Thailand. There have been rare instances of the infection in other parts of Asia, Colombia, and the Middle East. Globally, there have been exceptional cases of infection from Capillaria hepatica as well as Capillaria aerophila.
Intestinal Capillariasis has the following symptoms: diarrhea and abdominal pain. Without treatment, Intestinal Capillariasis will result in autoinfection that leads to enteropathy followed by cachexia which could prove to be fatal. Hepatic Capillariasis has the symptoms of subacute or acute hepatitis along with eosinophilia. There is the possibility of dissemination to various organs. Hepatic Capillariasis can also cause death. Pulmonary Capillariasis manifests as asthma, pneumonia, fever, and coughing. Pulmonary Capillariasis is also potentially fatal.
Diagnosis of Intestinal Capillariasis caused by Capillaria philippinensis is done by examining stool samples for eggs, adult worms, or larvae. Intestinal biopsies may also be used. Diagnosis of Hepatic Capillariasis caused by Capillaria hepatica requires a sample of liver tissue through biopsy or through necropsy. Diagnosis of Pulmonary Capillariasis caused by Capillaria aerophila requires a stool sample examination for eggs or a lung biopsy.
Overall, microscopy and morphologic comparison with various intestinal parasites are required for diagnostic findings. Treatment for Capillariasis is a prescription drug called Mebendazole. An alternative medication is Albendazole.