Filariasis - Causes, Symptoms, Diagnosis, and Treatment

What Is Filariasis?

A parasitic condition called filariasis is brought on by three different worm species. These worms' adult stage can only be found in human lymphatic systems. This system is in charge of preventing infections and preserving the body's fluid equilibrium. Over 120 million people in 72 tropical and subtropical nations, including Asia, the Western Pacific, the Caribbean, South America, and Africa, are affected by the disease.

How Is Filariasis Caused?

Any one of the three varieties of the following filarial worms can infect a person and lead to lymphatic filariasis:

• Wuchereria bancrofti (responsible for 90 percent of the cases).

• Brugia malayi (remainder of the cases).

• Brugia timori (very rare).

These roundworms (nematodes) are members of the Filarioidea family. When mosquitoes (Culex, Anopheles, and Aedes) bite and become infected by the worms in the afflicted person's circulation, they disseminate this disease from one person to another. Adults typically have these worms live in their lymphatic vessels for five to seven years, interfering with their natural function. Millions of immature larvae known as microfilariae are produced in the blood as they develop into adult forms at this location.

Who Is at Risk for the Infection?

The greatest risk of infection is among residents of tropical and subtropical regions who are subject to frequent mosquito bites over the course of several months to years. Visitors to these nations are comparatively less in danger.

What Are the Signs and Symptoms of Filariasis?

Filariasis presents asymptomatic, acute, and chronic forms. The majority of infected people do not show external clinical symptoms. However, the parasite continues to damage the lymph system and kidneys and plays a role in disease transmission.

In the chronic forms, the patient may experience elephantiasis (thickening of skin or tissue) of the limbs, hydrocele (swelling of the scrotum in men), or lymphoedema (swelling of the lymph tissues due to fluid accumulation). These symptoms emerge years after the parasite infection and are typically the result of the lymphatic system's dysfunction, resulting in fluid build-up and edema. This typically affects the legs but can also affect the arms, breasts, and genitalia in men, leading to hydrocele.

During acute episodes of symptoms, certain filariasis patients have eosinophilia (high numbers of specific white blood cells), immunoglobulin E (IgE), and anti-filarial antibodies in high amounts. When the inflammation goes away, these levels go back to normal. Due to swelling and impaired lymph system function, the body will therefore struggle to fight infections. This causes bacterial infections of the epidermis and lymphatic system to coexist. Elephantiasis, a condition where the skin thickens and hardens, is visible. With proper skin hygiene and wound care, many bacterial infections can be avoided.

What Are the Differential Diagnoses of Filariasis?

The following are among the possible diagnoses:

• Onchocerca, dirofilaria, brugia, dipetalonema, loaina, and meningonema are a few zoonotic filariasis.

• Lymphoma.

• Testicular tumors.

• Defects in the lymphatic system during birth.

• Pelvic cancer.

• Lymph system damage brought on by surgery or radiation.

How to Diagnose Filariasis?

The following tests can be performed to diagnose filariasis with the help of a blood sample:

• Microscopic Testing: The blood sample is analyzed under a microscope to identify the filarial worms, which is the conventional way of diagnosing an active filarial infection. Because filarial worms are nocturnally periodic and can only be found in the blood circulation at night, finding them can be difficult. Blood must only be drawn at night to correspond with the worms' blood circulation.

• Antibody Testing: The alternative to detecting filarial infection is antibiotic testing. The products that the body produces in response to the sickness are called antibodies. Any time of the day is suitable for conducting this test. However, if the tests are performed after lymphedema has manifested, they will come out negative.

• Scrotal Ultrasound: Males who are otherwise asymptomatic may exhibit adult worm movement when they undergo scrotal ultrasonography. A pattern of worm movement known as the ‘filarial dance sign’ can be seen in the lymphatic veins of affected males.

What Is the Treatment for Filariasis?

Along with anti-filarial treatment, the symptoms that are currently present must be addressed.

The treatment of filariasis may include:

Medications:

The Mass Drug Administration (MDA) recommended by the World Health Organization (WHO) includes anti-parasitic drugs such as Ivermectin 200 mcg/kg, Albendazole 400 mg, or Diethylcarbamazine 6 mg/kg are administered to the patient. These medications either eliminate the adult worms in the bloodstream or prevent them from breeding. Receiving these medications can also stop the virus from spreading to other people. Since the worms may still be present in the human body, one should take these drugs for several weeks at a time every year.

Surgery:

To remove dead worms from the bloodstream, surgery may be employed. A patient with filariasis who develops a hydrocele may occasionally need surgery to reduce fluid buildup in the scrotum.

Management of Elephantiasis:

Treatment can be provided to manage the swelling using elevation and compression garments.

Management of Lymphedema:

Lymphedema occurs even after the worms are dead. Therefore, it is vital to be aware of its management.

• Every day, the swollen region needs to be carefully cleaned with soap and water and dried.

• To allow the fluid to drain, elevate the swollen arm or leg both throughout the day and at night.

• Exercises can also be done to increase lymph flow and help the fluid travel more easily.

• Use an antibiotic or antifungal lotion to clean any wounds, and cover them if necessary.

• Put on shoes that fit the feet according to their current size. This will safeguard the feet from harm and keep them from falling.

What Is the Prognosis of Filariasis?

If filariasis is identified quickly and treated to stop deformities, the prognosis is favorable. Five annual doses of DEC (Diethylcarbamazine), either alongside or without Ivermectin or Albendazole, are often effective in treating the condition. The onset of symptoms is delayed until later in adulthood and is correlated with a rising worm burden. The most severe type, elephantiasis, results from chronic infections that have been added on top of acute infections over many years. Although there are some treatments for lymphedema, once the condition has progressed, it is challenging to control.

Conclusion:

The easiest approach to avoid getting infected is to protect oneself against mosquitoes, which are the main carriers. Most of the time, these mosquitoes bite between dusk and the dawn. If someone is traveling to or living in a tropical or subtropical region, they should take the following precautions:

• Use a mosquito net to cover the bed.

• Put on completely covered, light-colored clothing.

• Apply insect repellent on exposed skin, especially between dusk and dawn.

The World Health Organization advises using preventative chemotherapy to safeguard those who reside in areas prone to filariasis and take an annual dose of particular chemotherapy drugs. Adult worms are barely affected by these drugs. They can, however, stop youth worms from procreating and stop the parasites from spreading into mosquitoes.