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

• Mesocestoid Lineatus Infection
• Mesocestoid Variabilis Infection
• Mesocestoides Infection

What is Mesocestoidiasis? (Definition/Background Information)

• Mesocestoidiasis is an extremely rare infection caused by a parasitic tapeworm (Cestodes) that mostly infect wild and domestic animals. It is caused by the consumption of raw or undercooked meat of the infected animals
• The condition primarily affects small arthropods (spiders and beetles) and secondarily affects small mammals, birds, reptiles, and amphibians when these animals and birds consume an infected arthropod
• Tapeworm eggs are excreted by the secondary host that are again consumed by an arthropod to continue the life cycle. In very rare cases, humans can become infected after consuming a secondary host
• Mesocestoidiasis develops in the intestine and is often asymptomatic (no significant signs and symptoms are noted). The only symptom associated with the disease is diarrhea. However, because only a few cases have been reported, the associated symptoms are not well-documented or recognized
• Long-term complications of infection include the proliferation of intestinal granulomas and cysts. Mesocestoidiasis can be treated with prescribed medication by a healthcare provider. The condition is usually cured within two weeks of treatment and the outcomes are generally excellent

Who gets Mesocestoidiasis? (Age and Sex Distribution)

• Individuals of any age group who consume contaminated meat is at risk for Mesocestoidiasis infection
• Both male and female genders are at equal risk for infection
• Mesocestoidiasis is known to be present on every continent except Australia. It is thought to be prevalent among wild secondary hosts in varying levels
• However, it is a highly uncommon condition in humans with only 11 documented cases in the last decade - 7 in Japan, 2 in the United States, 1 in South Korea, and 1 in South Africa

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

• Individuals, who consume raw or undercooked mammals, birds, reptiles, and amphibians (that are secondary hosts for the parasite) have a higher risk for contracting Mesocestoidiasis

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 Mesocestoidiasis? (Etiology)

Mesocestoidiasis is a gastrointestinal infection that is caused by consuming uncooked or undercooked meat of animals infected by tapeworms belonging to Mesocestoides spp. The two species known to cause the infection include Mesocestoides lineatus and Mesocestoides variabilis.

• Humans contract the condition by consuming raw or undercooked meat from an infected secondary host. Any animal that consumes infected arthropods (that are primary hosts) may be a secondary host and a vector for human transmission
• Once the parasite is within the secondary host, it matures from a second stage larva to a third stage larva (tetrathyridium). A tapeworm in the tetrathyridium stage is the only stage capable of infecting humans. This means that consuming mesocestoid eggs or secondary larva will not result in an infection

In Japan, several cases have been linked to the consumption of raw ophidian liver, a religiously symbolic practice. In the United States, one case has been linked to the consumption of undercooked partridge meat.

What are the Signs and Symptoms of Mesocestoidiasis?

• Mesocestoidiasis is often asymptomatic and could go easily unnoticed
• In advanced cases, infected individuals are known to have prolonged diarrhea and other recurrent gastrointestinal symptoms
• Other symptoms noted may include:
• Nausea and vomiting
• Anemia that may result in weakness, fatigue, pale skin, and shortness of breath

How is Mesocestoidiasis Diagnosed?

A diagnosis of Mesocestoidiasis may involve the following tests:

• Complete physical examination and evaluation of medical history
• Ova and parasites stool test: Frequently, Mesocestoidiasis is diagnosed via a stool sample after patients complain about diarrhea. Mesocestoid egg sacs can be visible in infected excrement under microscopic observation
• Additionally, diagnosis can be confirmed via serological examinations. The presence of an antibody in blood is specific to Mesocestoidiasis and can be used to confirm the 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 Mesocestoidiasis?

The complications of Mesocestoidiasis may very rarely include:

• Prolonged infection can result in intestinal granulomas (tissue inflammation in response to infection) and intestinal cysts (that are pus-like structures that form from infection)
• This could lead to a variety of gastrointestinal issues such as intestinal obstruction and bleeding

How is Mesocestoidiasis Treated?

• The treatment for Mesocestoidiasis is the administration of a singular oral dose of praziquantel, an anti-parasitic drug that is commonly used to kill the same parasite in dogs and cats
• Once the dose is administered, a follow-up visit with the healthcare provider can help confirm if the infection is cured

How can Mesocestoidiasis be Prevented?

Mesocestoidiasis can be prevented by thoroughly cooking food that may be contaminated with the parasite.

• Avoid raw meat that is not from a reliable source (not properly processed and packaged)
• Follow basic rules while cooking and consuming food such as carefully washing meat, washing food vessels, cutting boards, before use; cooking meat to the required temperatures to kill any microorganism; washing hands before eating, or immediately on handling raw meat, etc.
• In case meat is minced or ground at home, ensure that the grinder machines are cleaned regularly after each use
• Sample tasting of meat while it is being cooked or while still undercooked, is to be completely avoided

If a Mesocestoides Infection is suspected, do consult with a healthcare provider immediately.

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

• Without treatment, Mesocestoidiasis can lead to the formation of intestinal granulomas and cysts. If these bodies are untreated, gastrointestinal issues, such as intestinal obstruction and bleeding can occur
• Furthermore, gastrointestinal issues may increase the risk for other gastrointestinal diseases such as Crohn’s disease and inflammatory bowel disease (IBD)
• With appropriate treatment (a single dose of praziquantel) the infection can be eliminated. Once the infection has been treated completely, there is no further evidence of any direct and long-lasting complications

Additional and Relevant Useful Information for Mesocestoidiasis:

• Even though Mesocestoidiasis is very uncommon in humans, it is very common in household dogs and cats in the United States
• There is a vaccination available for Mesocestoides Infections for dogs and cats (under the umbrella of tapeworm vaccination), but no vaccination for humans are currently developed
• Over 70% of European foxes may be infected with Mesocestoidiasis. From a random sample of 120 wild African dogs, 34% of them were found to be infected

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

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