Wuchereria bancrofti, or W. bancrofti, is the parasite responsible for lymphatic filariasis, popularly known as elephantiasis, which is a more common disease in warm and humid climate regions, mainly in northern and northeastern Brazil.
This parasite is transmitted by the mosquito bite of the genus Culex sp. infected larvae, which release infectious larvae into the person’s bloodstream as they move into the lymph vessels, resulting in an inflammatory response and characteristic symptoms of lymphatic filariasis, such as swelling of the leg, arm or other area of the body where the parasite is present, such as fever and muscle pain.
Understand what filariasis is and how to recognize symptoms
Wuchereria bancrofti has two evolutionary forms, microfilariae and adult worm. The microfilaria corresponds to the juvenile form of the parasite and is the form found in the bloodstream and lymph nodes, while the adult form of the parasite is present in the lymph vessels and produces more microfilariae, which are released into the bloodstream.
It has two life cycles, one in the mosquito and one in the human. The Culex quinquefasciatus mosquito, when it bites an infected person, inspires microfilariae, also known as L1, that develop over a period of 14 to 21 days in the mosquito’s intestine to the L3 phase and then migrate to the mouth.
When it bites another person, the mosquito transmits the L3 larva, which migrates to the lymph vessels and develops to stage L5, which corresponds to the stage of adult and sexual maturation. The L5 larva, after the incubation period, begins to release the microfilariae circulating in the blood.
Diagnosis of the infection is made by laboratory tests, as symptom diagnosis is, in most cases, difficult because the disease can be asymptomatic or have symptoms similar to other diseases.
Laboratory diagnosis is made through research of microfilariae in peripheral blood, it is important that the blood sample is performed at night, because it is during the night that the parasite is in the highest concentration in the blood, allowing diagnosis.
After the sample, the blood is sent to the lab to be analyzed through the coarse droplet, which is a technique that allows the visualization and count of microfilariae between blood cells. In addition, other diagnostic techniques, such as PCR and immune tests to identify antigens or antibodies against the parasite, may be performed.
Preventing Wuchereria bancrofti infection requires measures to prevent reproduction and bite of the mosquito responsible for transmitting the disease, it is recommended to use musketeers, use repellents and avoid standing water, for example. In addition, it is important to invest in environmental hygiene measures, as it is also possible to avoid mosquitoes.
Treatment of W. bancrofti should be done according to the doctor’s advice, it is generally recommended to use diethylcarbamazine for approximately 12 days. This remedy is the most suitable to control this parasite, since it acts against both adult and microfilariae worms. In some cases, the use of ivermectin may also be recommended, but this remedy does not work against adult worms, but only against microfilariae.