Filariasis

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Filariasis

Lymphatic Filariasis is also known as Elephantiasis

What is Filariasis?

Filariasis a parasitic disease transmitted by black flies and mosquitoes. These parasites are thin, round,  worm-like organisms. They appear white or translucent when observed under a microscope.

The life span of filariae would be around 5 to 7 years. During their lifespan, they produce millions of larvae. The size of the female is between 250 to 300 μm long and the size of the males is roughly half as long as the females.

How is Filariasis Transmitted? 

The causative organisms for Filariasis is a roundworm of the Filarioidea type. However, this is a vector-borne disease, with the primary vectors being mosquitoes and black flies. The infection spreads when a mosquito bites an already infected individual and then, goes on to bite a healthy person. This causes the larva of this parasite to enter the bloodstream of a healthy host and multiply. The complete stage of the larva to adult filarial worms is carried out within the lymphatic system. Once matured, the adult filarial worm starts to release larval forms called microfilariae. The newly generated microfilariae again enter into the mosquito along with the host’s blood and the cycle repeats itself. This parasitic disease is categorized on the basis of which body part is infected:

  1. Lymphatic filariasis: As the name suggests, this type affects the lymphatic system.
  1. Subcutaneous filariasis: In this case, the bottom layer of the skin and white part of the eyes are infected by the worms.
  1. Serous cavity filariasis: In the case of this disorder, the serous cavity of the abdomen is infected by the helminths.

There are more than a hundred species of filarial worms are currently discovered. Among them, only 8 to 9 are categorized as filarial parasites, which causes infections in human beings.

Filariasis Cycle

Filariasis Life Cycle: From larvae to adult

Symptoms of Filariasis

 The general symptoms of filariasis during its early stages include:

  • Fever
  • Chills
  • Headache
  • Skin lesions are observed in the beginning stage i.e., between three months to nine months after the insect bite

These symptoms are seen in the later stage:

  • Blockage in the lymphatic system which leads to oedema
  • Swelling, redness, and pain in the arms and legs
  • Accumulation of pus in cells

The formation of pus in a cell due to the dying worms or a secondary bacterial infection results in:

  • Skin rashes.
  • Abdominal pain
  • Damage to the cornea, choroid, retina and optic nerve finally resulting in loss of vision.
  • The hyper or hypopigmented skin on the face, arms, feet, and other parts of the body.
  • If these symptoms are neglected, the final stage of this disease would result in gross enlargement of the limbs and genitalia in a condition called elephantiasis.

Explore: Symptoms of Various Diseases

Filariasis Diagnosis

It is quite difficult to diagnose this disease as the symptoms vary from one type to another type and the symptoms diagnosed in the early stage are similar to normal viral and bacterial infections.

However, there are a few diagnostic processes carried out through body analysis, physical examination, body fluid test, including a blood test and urine test. Apart from these tests, few blood tests are carried out during the night time as the larvae are found most active at night.

A popular diagnostic procedure involves blood being drawn from a larger vein and smeared on a glass slide. This slide is then examined under an electron microscope to check for the presence of parasitic larval roundworms. The presence of Filariasis is examined with the help of the Giemsa stain. The other diagnosis for subcutaneous filariasis is performed with a skin snip test.

Treatment for Filariasis

Currently, there is no vaccine available for filariasis. Scientists are still working on developing a cure for filariasis.

Prevention is better than cure. As we all know, this disease is caused by the bite of mosquitoes, it is better to prevent the cause of this disease by:

  1. Wearing long sleeves and pants to prevent the bite of mosquitoes
  2. Apply DEET- based insect repellents
  3. Preventing the build-up of stagnant water
  4. Using mosquito mats, coils and nets if possible
  5. Though scientifically unproven, dark-coloured clothing attracts mosquitoes, so it might be beneficial to avoid them.

In spite of all these measures, if filariasis is contracted, the best treatment would be a course of anthelmintic drugs or antibiotics. Anthelmintic would be the best option as it directly kills the worms. But if this isn’t feasible, antibiotics are a great alternative because they target the symbiotic bacteria that are present inside the worms. When the antibiotics kill these bacteria, the worms cannot survive and thrive inside their hosts, eventually hampering reproduction.

Further Reading: Parasites And Symbiosis

Conclusion

The parasitic roundworms belong to the family of Filarioidea and Phylum Nematoda. This particular species is known by the name filarial worms or filariae and the infection caused by them is called filariasis.

General symptoms of filariasis include fever, chills, headache and skin lesions. Further progression of the disease will disfigure the patient with excessive swelling of the limbs.

Further Reading:

Find more information on filariasis or any other related topics by exploring BYJU’S Biology.

 

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