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

• Acanthocephalan Infection
• Spiny-Headed Worm Infection
• Thorny-Headed Worm Infection

What is Acanthocephaliasis? (Definition/Background Information)

• Acanthocephaliasis is an infection of the digestive system that is caused by the Acanthocephalan parasitic worm, also known as the “thorny-headed or spiny-headed worm”, because of the hooks present on them. These worms require at least two different organisms (hosts) to complete their life cycle
• The main species known to infect humans are the Macracanthorhynchus hirudinaceous (definitive hosts are rats), Macracanthorhynchus moniliformis (definitive hosts are pigs), and Bolbosoma (mainly associated with marine animals)
• Acanthocephaliasis or an Acanthocephalan Infection occurs when the host ingests the parasite, which then infects the intestinal wall, where it feeds on nutrients (obtained by the host) as well as on the damaged cells
• The signs and symptoms of Acanthocephaliasis involve the digestive tract, and may include abdominal pain, diarrhea, bloody stool, and loss of appetite 
• A treatment for Acanthocephaliasis is typically undertaken using prescription antiparasitic medications that kill the infecting worms, which are then passed in stool. With appropriate treatment, the prognosis of the infection is mostly good

Who gets Acanthocephaliasis? (Age and Sex Distribution)

• Acanthocephaliasis occurs very rarely in humans
• And, when humans are infected, no age, gender, or racial/ethnic bias is observed
• However, most cases occur in areas where people regularly consume insects for culinary, medical, or religious ritual purposes

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

• A major risk factor for Acanthocephaliasis is the consumption of insects

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones 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 health care provider.

What are the Causes of Acanthocephaliasis? (Etiology)

Acanthocephaliasis is contracted by primarily eating insects, which are the intermediate hosts of Acanthocephalans (types of parasitic worms).

• The infection develops when the thorny-headed worm invades the intestinal wall. Once embedded into the host’s intestinal tissue, it feeds-off acquired nutrients (from food that is consumed) and damaged cell tissue, the cell damage inflicted by the worm itself 
• The worm matures inside the host and is considered an adult worm, when it is able to lay eggs within the intestinal tract of the host (that is then passed through fecal matter) 
• Humans are not definitive, but accidental hosts of the Acanthocephalans worm. Humans may be infected, but generally do not transmit the parasite to another host

What are the Signs and Symptoms of Acanthocephaliasis?

Acanthocephaliasis in humans may remain without any symptoms (asymptomatic), or be cleared before it is able to affect the body. In some, it may be associated with symptoms such as: 

• Worms in stools
• Severe or acute abdominal pain/distension 
• Fever 
• Nausea 
• Bowel problems (diarrhea, constipation, and bloody stools)
• Weight loss 
• Decreased appetite

How is Acanthocephaliasis Diagnosed?

Acanthocephaliasis is diagnosed by the following tests and exams:

• A thorough physical examination 
• Evaluation of medical history, including an individual’s recall of consuming insects
• Assessment of symptoms
• Ova and parasites stool test, to detect the presence of adult worms in stool
• Blood tests: The serum samples may show a rise in eosinophils, although these only give evidence of generalized parasite infection. Eosinophils are a type of white blood cells that are elevated when the body is fighting infection

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 Acanthocephaliasis?

Potential complications of Acanthocephaliasis include:

• Dehydration due to persistent diarrhea 
• Perforation of the intestinal wall leading to leakage of intestinal and fecal matter into the peritoneum, causing peritonitis
• Secondary infection and sepsis

How is Acanthocephaliasis Treated?

The treatment of Acanthocephaliasis may involve the following measures:

• Administration of antiparasitic drugs to kill and help pass the worms in stool  
• Antibiotics (if needed) to help combat any secondary infection caused as a result of the parasite
• Additional medication for symptomatic treatment, as deemed necessary by the healthcare provider (such as for pain and fever)

How can Acanthocephaliasis be Prevented?

Acanthocephaliasis may be prevented by considering the following measures:

• Avoiding the consumption of bugs and insects
• Washing of hands prior to eating
• If traveling to foreign destinations, being aware of their culinary, religious, or medical customs that may involve the eating of insects 
• Ensuring that insect infestation at homes (particularly in the kitchen) is taken care of 

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

• The prognosis of Acanthocephaliasis is generally good with early diagnosis and prompt/effective treatment
• Despite a few documented cases of Acanthocephaliasis, largely the infection is not considered to be a life-threatening or fatal disease

Additional and Relevant Useful Information for Acanthocephaliasis:

• The life cycle of Acanthocephalan worms is described:
  • Eggs pass into the environment from a definitive host, such as pigs or rats, via their feces 
  • A primary intermediate host (an insect) eats the eggs; the eggs hatch and the larvae develop into an infective worm known as a “cystacanth” after about 10 weeks
  • If the insect is then consumed by another animal, the worm attaches to the intestinal wall of this ‘new’ host
  • Once the definitive host (usually not humans) is infected, the worm will develop into an adult and lay eggs, to be passed in the feces
• An adult M. moniliformis can grow up to 10 cm in length