There are three types of filariasis, classified according to the site of infection. Are they:
Lymphatic filariasis is the best known among the types of filariasis, and is often called elephantiasis. The worms responsible for this variation are Wuchereria bancrofti , Brugia malayi and Brugia timori . The parasites lodge in the lymphatic vessels and cause lymphedema.
In this type, worms lodge in the subcutaneous layer of body fat. The parasites responsible for subcutaneous filariasis are those popularly known as “Guinea worm” and “Larva do Olho”.
Filariasis of the serous cavity
This filariasis is caused by the microorganisms Mansonella perstans and Mansonella ozzadi , which occupy the serous cavity of the abdomen.
The main cause of this disease in Brazil, as well as in Africa, is the Wuchereria bancrofti worm . Other pathogens are Brugia timori and Brugia malayi , which are present in Southeast Asia, Indonesia, the Philippines and southern India
The filaria Wuchereria bancrofti lives most of its life in humans, the only definitive host of this species. The worms lodge in the lymphatic system and curl up in the form of a ball, thus disrupting the circulation of the lymph.
It is worth remembering that filariasis is not a disease that is transmitted from one human being to another . For infection to occur, it is necessary for an intermediate host (mosquito or fly) to become infected and then pass the worm on.
The reproduction of these worms occurs sexually, about eight months after entering the human body. From the reproduction, puppies originate, called microfilariae, that travel through the blood and move to the main organs.
Filariasis in Brazil
Filariasis spreads mainly in hot and humid countries (tropical and subtropical), but it was not always present in Brazil. It is believed that the disease was introduced to the country through the importation of African slaves.
The method of transmission of filariasis is the bite of insects known as intermediate hosts or vectors, which can transmit the filariasis larva to the human body. In Brazil, the most well-known and highly proliferating vectors are the species Culex (mosquito), Chrysomya (blowfly) and some species of Anopheles .
Although the male and female contract filarial larvae, only the female is able to transmit it to people. About eight months after the initial infection in humans, the filariae begin to reproduce, making the individual a definitive host.
During the day, the parasites lodge in the lung and during the night they circulate through the lymphatic and circulatory systems. The reason for this pattern is not known, but experts believe it is due to the fact that the main transmitter of the disease, the mosquito, has mostly nocturnal habits.
When biting a host with microfilariae, the vector ingests the larvae. When they enter the mosquito’s body, the larvae go to the wall of their stomach and then invade their chest.
When they are established in the thoracic muscles, the filariae undergo morphological transformations until they become unsustainable for the mosquito. Then, they come out of the chest and pierce the vector’s lips, attracted by the heat of the human skin being bitten.
Once the vector creates the lesion on human skin and the filaria enters the orifice, the process of implementing the parasite is completed.
Upon entering the human body, the worms penetrate the lymphatic vessels and migrate to the places of permanent permanence. It takes about a year for the branches to become adults and reproduce.
Groups of risk
Filariasis is reported mainly in tropical and subtropical regions , always reaching the most peripheral areas.
In Brazil, the greatest risk is found in the states of Pará, Amazonas, Pernambuco and some cases in Santa Catarina. This does not mean that people outside the highest risk areas are immune, but that they are less likely to be bitten by an insect that is infected with filariasis.
Carelessness with personal hygiene also leads to the proliferation of worms.
Early on, filariasis can be a silent (asymptomatic) disease. However, after the death of the first adult worm, the symptoms commonly reported are:
- Painful tenderness and redness along the lymphatic vessel;
- Genital lesions;
- Swelling of the limb;
- Photophobia (sensitivity or aversion to light);
- Lymphadenitis (lymph node infection);
- Microfilaremia (microfilariae in the blood).
Prevention is essential, as the disease is often asymptomatic, that is, it does not manifest symptoms until it is in an advanced stage.
How is the diagnosis of filariasis made?
The diagnosis of filariasis is complex and needs to be carried out by competent professionals, such as general practitioner and infectious disease . Usually, the doctor can order blood tests, biopsy of the affected tissues, ultrasound or serology by ELISA. Understand:
To check the presence of microfilariae in the blood, the test must be carried out between 11 pm and 1 am, due to their active behavior at night.
Biopsy involves the collection of affected tissues, such as lymph nodes. The sample is stored and analyzed against healthy tissue. In this way, the specialist will detect if there is an infection by filarias.
Brazil was a pioneer in using ultrasound to diagnose filariasis. According to scholars, the researchers were able to identify adult and live worms in the lymphatic vessels of the scrotum.
The purpose of ELISA serology is to look for the natural antibodies that the body produces to stop the action of parasites.
As the lymphatic system plays an important role in the immune system, it is possible to evaluate antibodies and their reactions to the filarias.
The benefit of serology is that it can be performed at any time, other than a blood test.
Filariasis has a cure?
Yes and no, it depends on the type of filariasis . When lymphatic, filariasis is an incurable parasitosis . However, the other types (subcutaneous or serous cavity filariasis) can be cured.
What is the treatment for filariasis?
If discovered early, filariasis is mainly treated with medication, and treatment can take up to ten years .
When it comes to lymphatic filariasis, there is still no cure. However, it is necessary to start the treatment as soon as possible, in order to stop the worms from acting and prevent the deformities from getting worse.
Medicines will kill microfilariae within a short time. Adult worms, on the other hand, because they are more resistant, take longer to die. In some cases, when drug treatment is not effective, surgical removal of the worms is indicated.
Much research is still being done on how to cure filariasis. Recently, two German scientists discovered an enzyme that disrupts the worm’s life, but are still studying the possibility of producing drugs with the enzyme.
The drugs commonly indicated for filariasis are:
- Ivermectin ;
NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.
Living with filariasis is not easy, especially when it progresses to elephantiasis.
In its most advanced stage, tasks that previously seemed to be easy to solve become a problem for those affected by the disease.
Exaggeratedly large limbs weigh and hurt, which hinders locomotion. In addition to the physical factors that need special care, there is also social prejudice, causing the carrier to become a recluse.
Keeping the affected area well sanitized is essential, so the chances of the disease stage advancing are reduced.
When properly cleaned, the limbs affected by filariasis do not usually progress to elephantiasis, as filariasis, in itself, is not its only cause.
The prognosis is favorable when the disease is discovered at the stage of microfilariae.
Symptoms such as fever , chills and nausea are the first to appear, as they occur shortly after the death of the first adult worm.
If the diagnosis of lymphatic filariasis is only conclusive after the acute form of the disease, then the individual will have a negative prognosis, needing to live with the disease until the end of life.
If treatment is not started quickly, the most common complications are:
This complication occurs when the lymph is unable to circulate properly. The serous fluid that was supposed to diffuse ends up accumulating in the testicles.
In its advanced stage, filariasis leads to the overgrowth of the affected limb. It is at this stage that the disease is characterized as elephantiasis.
Lymphatic varices may appear in the scrotum, triggered by the non-circulation of the lymph.
When a lymphatic vessel has more worms than it can handle, it breaks. Along with the rupture, there is also the rupture of blood vessels, and the fluids of the lymphatic and blood vessels enter the urinary excretory system.
The same process that occurs in hematoquiluria, is repeated in kiluria. However, with two additional ones: fat is also included in the lymphatic fluids, and blood is found in lesser quantities.
Filariasis worms can accumulate in the lung tissues and proliferate in the organ.
Abnormalities in the affected limb, such as increased thickness, loss of elasticity, hair loss, among others, are due to the low circulation of body fluids to the infected part.
How to prevent filariasis?
The first step towards prevention is the treatment of infected people. Thus, the microfilariae present in the organism and which could be transmitted to insects are eliminated.
The WHO also recommends prophylactic treatment with Diethylcarbamazine for endemic regions, such as in Recife and Pernambuco, once a year.
After going through the process of cleaning the microfilariae, the individual can completely cure the disease, but he becomes more susceptible to it. To prevent the episode from recurring, it is necessary to prevent it. Some tips are:
Eliminate the vector
A good way to avoid acquiring the disease is to avoid exposure to the transmitting mosquito. If you are unable to fully protect yourself from these insects, use precautions such as:
- Insecticides ;
- Repellents ;
- Mosquito nets (fly protection net).
Avoid endemic locations
Endemic location is the region where there is a high risk of contracting an infectious disease. In the case of filariasis in Brazil, the main locations are the states of Pará, Amazonas, Pernambuco and Santa Catarina. Abroad, we have India, Africa and some places in Asia.
If an extended stay in these places is necessary, be sure to use repellent.
I don’t live in an endemic location and I don’t intend to travel, am I safe?
Unfortunately, no one is free from getting filariasis, they are only less likely. Someone in your neighborhood, or even a family member, can travel and bring parasites on your body. This would trigger the worm proliferation process and individuals in the region would become susceptible.