From Mosquito Bites to Elephantiasis: The Life-cycle of Lymphatic Filariasis

Elephantiasis, another name for lymphatic filariasis, is a debilitating and severely deformative illness. It is brought on by infection with parasites that are categorized as nematodes, or roundworms, of the Filarioidea family and are spread by infected mosquito bites. Larvae spread by mosquitoes land on the skin, where they can enter the body. The transmission cycle is then continued when the larvae move to the lymphatic vessels and mature into adult worms.

People of all ages are impacted in communities where filariasis is spread. Even though the infection may have been contracted as a child, it may later cause visible symptoms like limb oedema, which can result in either a temporary or permanent disability. Lymphatic filariasis has a significant social and economic impact in endemic nations.

In 72 countries across the tropics and subtropics of Asia, Africa, the Western Pacific, and portions of the Caribbean and South America, lymphatic filariasis affects more than 120 million people.

It is typified by fibrosis, hypertrophy, and oedema of the skin and subcutaneous tissues as a result of lymphatic vessel blockage (lymphedema).The genitalia might be impacted.Although the term "elephantiasis" is frequently used to describe symptoms of parasitic worm infections, it can also refer to a number of illnesses that cause the body to swell in unusually large ways.

CAUSES:

Elephantiasis can manifest with a number of conditions, such as:

Filarial worms, which are microscopic parasitic worms, infect your lymphatic system and cause elephantiasis. These parasites cause fluid (lymph) to build up by blocking your lymphatic capillaries. Elephantiasis patients may also experience fever, swelling, and inflammation. Elephantiasis can lead to health issues if left untreated.

Filariasis, a parasitic infection caused by a particular kind of roundworm, can cause elephantiasis. Your body is invaded by tiny worms that are invisible to the human eye. The filarial worms appear as threads when viewed under a microscope.

Filarial worms come in a variety of forms:

Nine out of ten infections are caused by Wuchereria bancrofti.

The majority of the disease's surviving cases are caused by Brugia malayi.

Infections can also be caused by Brugia timori.

Transmission

These roundworms are transmitted from person to person by mosquito bites, much like malaria. The parasite can be spread by a variety of mosquito species, such as Anopheles, which also spreads malaria, and Aedes, which spreads viruses like dengue and Zika.

In addition to being carriers, mosquitoes play a crucial role in the life cycle of worms. The insects consume the parasite's young larvae, known as microfilariae, when they bite an infected person. The larvae undergo a metamorphosis within the mosquito for one to two weeks, after which they spread to the skin and enter the body when the insect bites another person.

After entering, the worms mature into adults and congregate in the lymphatic system, releasing microfilariae into the bloodstream that mosquitoes can subsequently consume. And so it continues. Adult worms can survive and procreate inside the human body for six to eight years, and this can occur even in those who don't exhibit any symptoms.

The Parasite's Impact on the Body

The worms live in the lymphatic system, which is why they can cause such harm to the human body. Among other things, this intricate system of organs and tissues is in charge of controlling tissue fluid and shielding the body from illness.

However, these effects require repeated exposure to infected mosquitoes over a period of several months.

SYMPTOMS : 

About 2 in every 3 people who have lymphatic filariasis don’t have severe symptoms. But filariasis usually leads to a weakened immune system.

The majority of lymphatic filariasis infections are asymptomatic. Even though those who are infected with the microscopic worms are probably unaware of their infection, they can still infect others. Infections with lymphatic filariasis typically show no symptoms at all. Even though they may not be aware of their infection, people who are infected with the microscopic worms can still infect others.

Lymphedema

Although many people confuse lymphatic filariasis with elephantiasis, the condition that gives the appearance of more elephant-like features is actually lymphoedema. Extreme fluid accumulation and swelling in certain body parts, usually the legs, breasts, or genitalia, is known as lymphoedema. This inflammation can be extremely painful and occasionally accompanied by a fever.

Most individuals who develop lymphoedema do so years after initially contracting the parasite, and an estimated 15 million people worldwide currently suffer from this condition.

Hydrocele

Some men who have the parasite experience scrotal swelling. Lymphatic filariasis is thought to cause hydrocele in an estimated 25 million men globally.

Elephantiasis

 Elephantiasis is characterized by abnormally thick skin and underlying tissues. This frequently occurs as a result of secondary bacterial infections, which occur when the parasite damages the body's lymphatic system and suppresses the immune system.

Tropical Pulmonary Eosinophilia Syndrome

This consequence, which includes wheezing, coughing, and shortness of breath, is typically seen in infected people residing in Asia.

How does the spread of lymphatic filariasis occur?

Lymphatic filariasis spreads through mosquito bites. When a mosquito bites someone who has filariasis, the filarial worms in the person’s blood infect the mosquito. Then, when the infected mosquito bites another person, the worms pass into that person’s bloodstream.

In general, a person won’t get filariasis from a single mosquito bite. It usually takes repeated mosquito bites over several months (or even years) for a person to get the condition.

When these worms enter your bloodstream, they travel to your lymphatic system. There, they grow into adult worms. The adult worms stay alive for up to seven years. The filarial worms reproduce and release millions of worms into your bloodstream.

Complication Caused by Elephantiasis

Damage to your lymphatic system over time may impair your body's ability to fight off infections. As a result of this compromised immune response, you might experience:recurring infections caused by bacteria.Body parts that are painful, swollen, and enlarged are caused by thicker skin and fluid retention.Coughing and trouble breathing are symptoms of tropical pulmonary eosinophilia syndrome, which is caused by an increase in white blood cells.

Testing and Diagnosis

Medical professionals must analyze a blood sample in order to diagnose elephantiasis. They could make use of:

Blood test using a microscope : Your blood sample may be examined under a microscope by healthcare professionals. They can check for filarial worms in your blood using the microscope. Filarial worms only move in your blood at night because they are nocturnally periodic. You might have to have your blood drawn at night as a result.

Test for antibodies. : Your blood sample may be measured for antibodies by the providers. Your body produces organisms called antibodies in reaction to an infection. This test can be taken at any time of day.

Treatment and Management 

Medication and vector control are two methods of treating and managing lymphatic filariasis.The type and severity of your symptoms will determine your course of treatment. Treatment options for elephantiasis generally include:

Medications :

Everyone in an area, whether or not they have been diagnosed with lymphatic filariasis, is frequently given a combination of medications on a regular and proactive basis to stop the disease's spread.Because it successfully eradicates the microfilariae that mosquitoes can carry and transmit from person to person, this can help stop the parasite's spread, even though it won't cure everyone who has lymphatic filariasis or its many complications.

It is advised that different regions receive different treatment combinations because co-infections with other diseases can sometimes make the side effects of the medications worse. These consist of:

While ivermectin is mainly used in conjunction with albendazole in areas with onchocerciasis (or river blindness), diethylcarbamazine citrate (DEC) is frequently used in conjunction with albendazole in areas without onchocerciasis.

In some regions where onchocerciasis is not present, all three drugs may be advised.

DEC or Ivermectin (in onchocerciasis-affected areas) can be used to eradicate the parasite's microfilariae and some, but probably not all, adult worms in individuals who are already infected.

Vector Management

Reducing mosquito populations and preventing bites is a crucial preventative measure because mosquitoes are essential to the spread of diseases like dengue fever, West Nile virus, and malaria as well as lymphatic filariasis. This can be accomplished by

• Using insecticide-treated mosquito nets 
• In and around residential areas, spraying
• Donning long sleeves, long pants, and bug repellent with DEET (if available)

This can lessen the likelihood that someone will contract lymphatic filariasis, though it probably won't completely eradicate the parasite.

Surgery. To remove dead worms from your bloodstream, surgery might be necessary. You might also need surgery to remove any fluid accumulation in your scrotum if filariasis is the cause of your hydrocele.

Elephantiasis control. Additionally, your healthcare provider might suggest methods for controlling swelling, such as compression clothing or elevation.

Can lymphatic filariasis be cured?

For lymphatic filariasis, there is no treatment or vaccine. Many of the worms can be killed by medication, which also prevents you from infecting others. Additionally, treatment can lessen your symptoms.

PREVENTION 

Is it possible to prevent elephantiasis?

Avoiding mosquito bites is the best defense against elephantiasis, especially in tropical regions. Take the following precautions to avoid mosquito bites if you live in or visit areas where you could contract filariasi

• Take a nap beneath a mosquito net.
• Apply insect repellent, particularly at night, to exposed skin.
• Put on long sleeves and long pants.

The World Health Organisation (WHO) advises administering preventive chemotherapy to entire regions in areas where filariasis is prevalent. In this preventive approach, individuals who are susceptible to infection receive a yearly dosage of particular chemotherapy medications.

The drugs can prevent younger worms from reproducing, but they have little effect on adult worms. Additionally, they can stop the parasites from infecting mosquitoes.