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

• Bertielliasis
• Bertiellosis
• Human Bertiella Infection

What is Bertiella Infection? (Definition/Background Information)

• Bertiella Infection (or Bertielliasis) is caused by tapeworms (cestodes), belonging to the genus Bertiella. The infection occurs following the ingestion of an infected arthropod, normally an oribatid mite
• The mite serves as an intermediate host for the tapeworm. Individuals, who inadvertently consume the mite, are at risk for developing Bertiella Infection
  • The tapeworm resides in the human intestine, where the infection is often asymptomatic (presenting no symptoms)
  • The tapeworm produces eggs in the intestine, which are then released through defecation
  • Eggs in feces are consumed by oribatid mites, which act as the intermediate host for humans and primates
• The mite that causes Bertiella Infections is commonly found in guavas. Therefore, consuming wild guavas, particularly fallen fruit from the ground, may increase the risk of contracting the infection
• The infection frequently affects the old and new world primates (group of animals including monkeys and apes). Human infections are typically very rare
  • Much less than 100 human infections have been documented worldwide, with most of them originating in Southeast Asia
  • The infection of non-human primates is significant; since, the primates are often responsible for the spread of the disease
• Bertielliasis can either be asymptomatic, or present with signs of abdominal discomfort and pain, vomiting, anorexia, and loose or fatty stool
• Bertiella Infections are diagnosed by identifying tapeworm eggs in feces. This can be undertaken via a stool sample analysis, performed by a healthcare professional
• Treatment for Bertiella Infections include the administration of an anti-parasitic drug that can rapidly kill the parasite, ensuring a good prognosis for most individuals

Who gets Bertiella Infections? (Age and Sex Distribution)

• Bertiella Infections have been reported in many tropical climates, specifically Southeast Asia, South and Central America, and the Caribbean
• There have only been 58 reported human cases so far and, only two of the reported cases have been since the year 2003. Human Bertiella Infections are extremely rare and most of the cases are reported from Southeast Asia
• It is believed that children are more susceptible to Bertiella Infections, due to their underdeveloped immune systems
• All racial groups and ethnicities, both male and female genders are susceptible to the infection without any bias

What are the Risk Factors for Bertiella Infections? (Predisposing Factors)

The risk factors for Bertiella Infection include the following:

• Traveling to or residing in a tropical climate where cases of Bertiella Infections have been reported
• Coming into contact with (non-human) primates and the soil within their vicinity
  • Non-human primates are frequently affected by Bertiella Infections. This includes wild primates, primates in zoos, primate habitats, and pets
  • Examples of such primates include monkeys, chimpanzees, apes, and even lemurs
  • Primates act as a reservoir in which the parasite proliferates. Being around infected primates may increase the risk of contracting an infection
• Consuming fallen fruit on the ground: The mite that carries the tapeworm is frequently found in tropical fruits, especially guavas. Eating fruits fallen from trees, places one at risk for infection

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 Bertiella Infections?

• Bertiella Infections are caused by cestodes (tapeworms) belonging to the genus Bertiella. The two major species causing infection in humans are Bertiella studeri and Bertiella mucronata
• The infection occurs following accidental ingestion of an oribatid mite that is infected with the tapeworm parasite
  • The Bertiella tapeworm resides in select arthropods, frequently in the oribatid mites
  • Once the mite is ingested, commonly through contaminated food (such as fruits/guavas lying on the ground), the tapeworm is able to escape the mite and enter the human intestine, where it matures
  • A mature tapeworm can be anywhere between 10-30 cm (4-12 inches) long. Once mature, the tapeworm produces eggs in the intestine that are released from the body in the stools
  • Excreted eggs are then consumed by oribatid mites, which act as the intermediate host for humans and primates. This completes the replication cycle
  • Oribatid mites are very small, round arthropods about 1 mm (0.04 inches) in size. They are typically reddish-brown, but may be light-brown or dark-brown depending on the immediate surrounding environment

It is important to note that the tapeworm eggs are incredibly small and impossible to notice. They require a microscope to be visualized.

Note:

• Bertiella Infections cannot be transmitted from one individual to another. The parasitic eggs may be secreted via feces. However, the eggs must first develop in an arthropod before the parasite is able to infect humans again
• This indicates that there is no risk of contracting a Bertiella Infection from an affected individual; however, certain precautions must be taken as the parasite may be residing in the local environment/soil

What are the Signs and Symptoms of Bertiella Infections?

The most common signs and symptoms of Bertiella Infections include the following:

• Abdominal discomfort
• Abdominal tenderness
• Loose or fatty stools
• Vomiting
• Anorexia (weight loss and loss of appetite)

It is important to note that the presence of a sign or symptom does not confer infection. Additionally, infection can occur without any of the above signs or symptoms. Due to the rarity of Bertiella Infections, the list of signs and symptoms may be incomplete, and cases of the disease may be attributed to other more common infections.

How is Bertiella Infections Diagnosed?

A Bertiella Infection is diagnosed on the basis of the following tests and exams:

• A complete physical examination and an assessment of symptoms
• Evaluation of the affected individual’s medical and recent travel history
• Microscopic examination of stool sample to check for the presence of the following:
  • White parasitic eggs
  • Distinctive proglottids (segments of a mature tapeworm)

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 Bertiella Infections?

Due to rarity of Bertiella Infection in humans, the possible complications are not well-documented nor understood. Besides occasional discomfort, Bertiella Infections tend to be typically benign. There is no evidence of these infections causing severe medical conditions in humans.

However, the following rare cases of complications have been suspected:

• Intestinal obstruction
• Appendicitis (obstruction of the appendix)
• Bile duct obstruction
• Cholangitis - infection resulting from obstruction of the bile duct
• Cholecystitis - inflammation resulting from obstruction of the gallbladder

How is Bertiella Infections Treated?

Bertiella Infections are treated with anti-parasitic drugs that target tapeworms.

• The doses of the drugs are frequently based on the weight of the patient
• An appropriate drug treatment tends to kill the parasite; the proglottids get fragmented and are then excreted via the feces

How can Bertiella Infections be Prevented?

Bertiella Infections may be preventable by considering the following measures:

• Ensuring that there are no oribatid mites in food or within one’s living environment
• Avoiding the consumption of wild fruits or fruits picked-off the ground
• Avoiding handling monkeys or other non-human primates. If handling such primates is necessary, one should wash one’s hands thoroughly afterwards

What is the Prognosis of Bertiella Infections? (Outcomes/Resolutions)

• The prognosis of Bertiella Infections is good following adequate treatment 
• The infection generally resolves rapidly with no lasting symptoms or complications being typically noted

Additional and Relevant Useful Information for Bertiella Infections:

• Humans act as an accidental host in Bertiella Infections. Humans serve as a dead-end for the parasite and results in the termination of the parasitic replication cycle
• The disease is not intended to occur in humans; but it does occur, due to the similar nature of the human intestine to that of non-human primates (that are the intended host)
• Bertiella Infections are likely to be misdiagnosed as another parasitic infection, due to the rarity of these infections. But, the tapeworm that causes Bertiella Infections is very sensitive to anti-parasitic drugs and infection can be resolved
• There are 29 species of the Bertiella parasite but only two have been reported to infect humans, namely Bertiella studeri and Bertiella mucronata
• Being able to identify oribatid mites is important to ensure they are not in living environments, which can help prevent Bertiella Infections