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Brugia Malayi Infection

Last updated Aug. 9, 2018

Approved by: Maulik P. Purohit MD, MPH

Brugia Malayi Infection describes an infection of the lymphatic system resulting from the parasitic nematode (worm) Brugia malayi. The condition is transmitted through mosquito bites.

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

  • Brugia Malayi Filariasis
  • Infection due to Brugia Malayi
  • Malayan Filariasis

What is Brugia Malayi Infection? (Definition/Background Information)

  • Brugia Malayi Infection describes an infection of the lymphatic system resulting from the parasitic nematode (worm) Brugia malayi. The condition is transmitted through mosquito bites
  • Adult B. malayi are found in the lymph nodes. Their offspring, known as microfilariae, circulate in the blood stream. Upon taking a blood meal from an infected individual, a mosquito may transmit the disease to another individual
  • This condition is most commonly seen in South and Southeast Asia with rural populations being among those most affected. Individuals living in areas endemic to B. Malayi including visitors staying in such areas for extended periods of time are at the highest risk of contracting Brugia Malayi Infection
  • Brugia Malayi Infection is part of a classification of disease known as lymphatic filariasis. As such, individuals with the infection present with symptoms common to lymphatic filariasis including fever and swelling of the lymph nodes. Severe infections may lead to elephantiasis, which is the swelling and enlargement of the limbs
  • Treatment of Brugia Malayi Infection largely involves the use of anti-filarial drugs. Individuals with elephantiasis will need to take appropriate measures to care for their affected limb
  • The prognosis for Brugia Malayi Infection is generally good, as many individuals do not present with significant symptoms. For a small number of individuals in whom the infection leads to elephantiasis, the prognosis depends upon the severity of the infection

Who gets Brugia Malayi Infection? (Age and Sex Distribution)

  • Due to the fact that exposure to the worms and the mosquitoes that transmit them determines who gets Brugia Malayi Infection, there are no predisposing factors that are based on age, gender, race, or ethnicity
  • However, individuals living in areas endemic to the infection are most likely to contract it. This includes individuals living in rural areas of India, New Guinea, the Philippines, and other parts of Southeast Asia

What are the Risk Factors for Brugia Malayi Infection? (Predisposing Factors)

The risk factors for Brugia Malayi Infection include:

  • Living in or travelling to regions endemic to B. malayi
    • Individuals that are part of farming communities or that live in rural areas within South or Southeast Asia are especially susceptible to contracting the infection
    • Swamps and marshes should be avoided, as they are prime areas for mosquitos that may harbor B. malayi
  • Living with a compromised immune system

Importantly, having a risk factor does not mean that an individual will develop a certain condition. An individual with a risk factor, however, is more likely to develop a certain condition than an individual without a risk factor. In addition, some risk factors are more important than others.

The absence of a risk factor does not necessarily mean that an individual will not develop a certain condition. It is important to discuss the effects of risk factors with a health care provider.

What are the Causes of Brugia Malayi Infection? (Etiology)

Brugia Malayi Infection is caused due to an infection of the lymphatic system by the parasitic nematode (worm) Brugia malayi.

  • B. malayi is transmitted from an infected individual to an uninfected individual through mosquitos of the Mansonia, Aedes, Anopheles, and Culex genera
  • The mosquito injects larval worms into the individual while taking a blood meal. These worms travel through blood and lodge within the lymph nodes, where they remain throughout their adult lives
  • The adult worms reproduce and produce larval B. malayi. The worms in their larval stage within a human host are known as microfilariae
  • While the adult B. malayi are contained within the lymphatic system, B. malayi microfilariae circulate in blood. It is these microfilariae that are taken up by the mosquitos and subsequently transmitted to an uninfected individual, thereby passing on the infection

What are the Signs and Symptoms of Brugia Malayi Infection?

Many individuals do not present with any major signs and symptoms even when they have contracted Brugia Malayi Infection. For those individuals that do manifest with symptoms, the following may be noted:

  • Fever
  • Inflammation and swelling of the lymph nodes
  • Inflammation of the lymphatic vessels
  • Excess fluid within the lymphatic system
  • Possible formation of abscesses and ulcers at the lymph nodes
  • Elephantiasis, or hardening and thickening of the limb accompanied by severe swelling: This is very often seen in severe cases of Brugia Malayi Infection in which an individual has been bitten several times by disease-carrying mosquitos
  • Some individuals may develop symptoms resembling tropical pulmonary eosinophilia syndrome. The symptoms may include respiratory distress such as cough, wheezing, and shortness of breath

How is Brugia Malayi Infection Diagnosed?

  • A healthcare professional will undertake a full physical examination and evaluate an individual’s medical history before diagnosing Brugia Malayi Infection
  • A history of the areas the individual has travelled to or has lived in is also noted. Individuals who have travelled to or lived in areas endemic to the infection will have the highest suspicion of having contracted Brugia Malayi Infection

The following procedures/techniques may be used to diagnose Brugia Malayi Infection:

  • A laboratory diagnosis can help confirm the presence of B. malayi microfilariae in either the blood or the lymph. A blood or lymph sample will be taken between the hours of 10pm and 2am, as these are the times when the microfilariae are most active
  • Perhaps the most effective way of diagnosing Brugia Malayi Infection in rural populations that lack medical resources is the immunochromatographic test, or ICT. A simple prick of blood is used, and is placed on the ICT card’s sensor. The card will then display a positive or negative result for filarial infection
  • Increased levels of certain types of white blood cells and antibodies in the individual’s serum would also support a diagnosis of Brugia Malayi 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 Brugia Malayi Infection?

The complications of Brugia Malayi Infection are normally seen in severe cases of the infection:

  • Individuals living in endemic areas may be exposed to multiple rounds of the infection
    • The longer an individual is infected with B. malayi, the greater are the chances of developing elephantiasis, which is the hardening and swelling of the limb
    • Elephantiasis can decrease mobility and overall quality of life. In some countries, it may also lead to the individual becoming socially ostracized
  • The most common treatment for the infection, using DEC, may lead to fatal encephalitis (inflammation of the brain) in rare cases, due to massive death of the microfilariae

How is Brugia Malayi Infection Treated?

A healthcare professional evaluates and undertakes an appropriate treatment plan for Brugia Malayi Infection after evaluating the individual’s symptoms and possible diagnoses.

  • Diethylcarbamazine (DEC) has shown to be effective in eliminating both adult and microfilarial B. malayi.
  • DEC in combination with another drug (such as ivermectin or albendazole) has shown to be the most clinically effective way in treating Brugia Malayi Infection. Multiple doses over an extended period of time can usually help eliminate the worms from the body
  • Clinical studies have shown that bacteria of the genus Wolbachia are of critical importance to the life cycle B. malayi and other filarial worms. Antibiotics that kill Wolbachia have shown to be effective in eliminating B. malayi microfilariae from circulation

Individuals with elephantiasis must make sure to take proper care of the infected limb through the following techniques:

  • Washing the limb regularly with soap and water
  • Massaging the limb to improve circulation
  • Treating cuts and abrasions with antibiotic creams and ointments. Poor lymph circulation to the limbs makes the limbs more susceptible to infection

How can Brugia Malayi Infection be Prevented?

A prevention of Brugia Malayi Infection is mostly accomplished by preventing mosquito bites. To this end, many methods are effective and include:

  • Insect repellent
  • Clothing with long sleeves that cover the arms and legs
  • Mosquito nets
  • Sleeping in cool areas
  • Staying inside (home) during dawn and dusk in the endemic regions
  • Avoiding swamps and marshes, or other areas having standing water

At-risk populations are now being supplied with yearly doses of DEC in order to reduce the numbers of circulating microfilariae on a large scale level. Reducing the numbers of B. malayi microfilariae lowers the chance of an individual contracting Brugia Malayi Infection from an infected mosquito.

What is the Prognosis of Brugia Malayi Infection? (Outcomes/Resolutions)

The prognosis for Brugia Malayi Infection is generally good in a majority of cases. In individuals with severe infections, the prognosis may range from fair to poor.

  • Asymptomatic individuals may never know that they have contracted the infection, and will continue to lead normal lives
  • Individuals with mild symptoms may need to take DEC in combination with other drugs, and the prognosis is quite good
  • However, individuals with severe infection that progress to elephantiasis will have to continue to manage the infected limb, as the condition is irreversible at this stage
  • In addition, individuals are rarely known to have a severe reaction to DEC that may lead to encephalitis, or swelling of the brain. The prognosis for this rare drug reaction is usually poor

Additional and Relevant Useful Information for Brugia Malayi Infection:

  • Brugia Malayi Infection is part of a larger classification of disease known as lymphatic filariasis
  • There are currently aggressive campaigns to eliminate lymphatic filariasis from the world by the year 2020

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: July 20, 2016
Last updated: Aug. 9, 2018