Lymphatic filariasis can be asymptomatic, where infected people have no symptoms and never will develop symptoms. Other people that are infected will present with acute clinical symptoms [3].

Acute symptoms of the disease include:

• Adenolymphangitis (ADL) – this presents with sudden onset of fever and painful lymphadenopathy. ADL may occur due to immune mediated responses to dying adult worms. Many anatomic sites may be involved: the inguinal lymph nodes and lower extremities, genetalia (scrotum) are common sites.

• Filarial fevers – Filarial fever consist of self-limited cyclical episodes of high fever. In tropical settings, these fevers may be confused with other causes of fever in tropics such as malaria.

• Tropical pulmonary eosinophilia – This is caused by an immune hyper responsiveness to the microfilariae trapped in the lungs. It is characterized by wheezing at night. The “classic” presentation is: cough, fever, marked high eosinophilia count, high serum immunoglobulin E concentrations and positive antifilarial antibodies. Eosinophilia may exceed 3000/microL, although infections with other parasites may also result in such high eosinophilia levels.

In travelers (those that do not live in the endemic areas) – the exposure is usually insufficient to filariasis to develop chronic complications. However, these persons may manifest hypersensitivity reactions to the developing larvae: eosoinophilic infiltrate with lymphangitis and lymphadenitis, urticarial and rash.

Chronic symptoms include [4]:

• Lymphedema – This is swelling of the limbs due to chronic inflammation of the lymphatic vessels. It is a late symptom of infection. Severe lymphedema is sometimes referred to as “elephantiasis”. It can occur in the upper or lower extremities.

• Hydrocele – Chronic infection can involve the genitalia. Hydroceles can be as large as 30 cm in diameter. They are usually painless unless infected by bacteria. Adult worms can localize in the spermatic cord.

• Renal Involvement – Intestinal lymph may be discharged to the renal pelvis, causing lymphatic fluid to be passed in the urine (known as chyluria). It has a milky appearance to urine. Cyluria may affect an individual’s nutritional status and therefore should be addressed promptly. Hematuria and/or proteinuria can also occur when there is renal involvement. The exact mechanism for this is unknown.

• Swelling

  We present a case of subcutaneous firm to cystic swelling, aspiration of which revealed a large number of microfilaria. A 30-year-old man presented with a chain of intermittent, firm swellings in both arms. [ncbi.nlm.nih.gov]

  Other symptoms include fever, pain and swelling of lymph glands, headache, and inflammation of the lymph drainage areas, swelling of the scrotum, skin rashes and blindness. [doctor.ndtv.com]

  In men, lymphedema of the genitalia usually involves swelling of the scrotum, often to the size of a watermelon making it very painful and difficult to walk. In women, the condition may present swelling in one or both breasts. [end.org]

  Approximately 25 million men have genital swelling from the disease and an estimated 15 million more suffer from lymphedema (swelling) of the leg. Elephantiasis is closely associated with poverty. [sabin.org]

• Fever

  Diethylcarbamazine shows remarkable effect against filarial fever and hemato-chyluria. Oxophenarsine hydrochloride shows a satisfactory effect on filarial fever. [doi.org]

  Symptoms and Signs The symptoms that occur in persons affected by filariasis are: Fever with chills, Swelling in the area where the adult worms are present Enlargement of the lymph nodes Recurrent episodes of fever with chills can occur Inflammatory changes [webhealthcentre.com]

  This report describes a case of filariasis in a child who presented with fever and extensive lower-extremity edema. [ncbi.nlm.nih.gov]

  Filarial fevers – Filarial fever consist of self-limited cyclical episodes of high fever. In tropical settings, these fevers may be confused with other causes of fever in tropics such as malaria. [symptoma.com]

• Disability

  These patients are not only physically disabled, but suffer mental, social and financial losses contributing to stigma and poverty. [who.int]

  One of the world’s most disabling and disfiguring diseases, LF afflicts the poorest. [imaworldhealth.org]

  Lymphatic filariasis is a leading cause of permanent disability worldwide. Communities frequently shun and reject women and men disfigured by the disease. [cdc.gov]

  The Agency also provides support to countries to assist with morbidity management and disability prevention, with a focus on high-quality treatment and care to reduce suffering from chronic symptoms. [neglecteddiseases.gov]

• Inflammation

  Some of the inflammation is in response to antigens of the endosymbiotic bacteria Wolbachia, which the filarial worms contain Secondary lymphangitis and fibrosis may result Chronic inflammation leads to nonpitting edema, hyperpigmentation and hyperkeratosis [pathologyoutlines.com]

  The presence of living worms in the body is mainly asymptomatic but the death of adult worms leads to granulomatous inflammation and permanent fibrosis. [icd9data.com]

  Symptoms are primarily a response to adult worms that cause inflammation. Chronic inflammation may progress to hardening of the lymphatic vessels (fibrosis) and obstruction of the lymph flow. [rarediseases.org]

  Acute episodes of local inflammation involving skin, lymph nodes and lymphatic vessels often accompany the chronic lymphoedema or elephantiasis. [allcountries.org]

• Lymphadenopathy

  Ultrasonography (USG) of the breast suggested hypoechoic lesion in infero-medial quadrant of left breast and bilateral axillary lymphadenopathy. [atmph.org]

  Filarial fever: Often an acute fever that occurs independently of any other signs of lymphadenopathy. Filarial fever is sometimes misdiagnosed as a manifestation of malaria and other tropical diseases because of the lack of associated symptoms. [physio-pedia.com]

  Lymphadenopathy and hepatomegaly may be present. [emedicine.medscape.com]

  It is characterised by: Fever and painful lymphadenopathy in the groin and axillae. Affected areas being painful, tender, red and swollen - usually the result of superimposed bacterial infection. [patient.info]

  Acute symptoms of the disease include: Adenolymphangitis (ADL) – this presents with sudden onset of fever and painful lymphadenopathy. ADL may occur due to immune mediated responses to dying adult worms. [symptoma.com]

• Abdominal Pain

  Serous cavity filariasis may cause similar symptoms to those seen in the subcutaneous form, along with abdominal pain. A diagnosis of this condition is usually confirmed when a blood film shows the presence of microfilariae. [news-medical.net]

  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. [byjus.com]

  Symptoms include swelling of the arms, shoulders, and face; abdominal pain; itchiness; fatigue; and joint pain. [dermnetnz.org]

  Serous cavity filariasis presents with symptoms similar to subcutaneous filariasis, in addition to abdominal pain, because these worms are also deep-tissue dwellers. [en.wikipedia.org]

  Symptoms caused by the death of the parasites include fever, headache, muscle pain, abdominal pain, nausea and vomiting, weakness, dizziness, lethargy, and asthma. [encyclopedia.com]

• Arthralgia

  Diethylcarbamazine has common but limited side effects, including headaches, asthenia, arthralgia, anorexia, nausea and vomiting. Patients must be warned against the risk of somnolence after taking the product. [therapeutique-dermatologique.org]

  […] approximately 50% of adult worms Not distributed for use in the US, but can but can be obtained through the CDC under an Investigational New Drug protocol Has been added to salt in some endemic regions Side effects include fever, headache, anorexia, nausea, and arthralgias [physio-pedia.com]

• Insect Bite

  Each female worm can produce millions of larvae, and these larvae only appear in the bloodstream at night, when they may be transmitted, via an insect bite, to another host. [encyclopedia.com]

  Filariasis is an infection caused by a parasitic worm and is transmitted by insect-bites. It is more prevalent in the tropical areas of Africa, Asia, Central and South America. In India, it is common in eastern Uttar Pradesh and Bihar. [doctor.ndtv.com]

  More details on insect bite prevention. There is no preventive medication or vaccine against Lymphatic Filariasis. Lymphatic Filariasis nematode images, life cycle, and distribution maps: Infection Landscapes Information last updated: April 4, 2017 [iamat.org]

  When ingested by a suitable bloodsucking insect (mosquitoes or flies), microfilariae develop into infective larvae that are inoculated or deposited in the skin of the next host during the insect bite. [merckmanuals.com]

• Pruritus

  125.9 filariensis (see also Infestation, filarial) 125.9 Filariasis (see also Infestation, filarial) 125.9 due to Hematochyluria (see also Infestation, filarial) 125.9 Hydrothorax (double) (pleural) 511.89 Infestation 134.9 filarial 125.9 Itch (see also Pruritus [icd9data.com]

  Doxycycline treatment may be particularly beneficial for people with onchodermatitis and pruritus who would otherwise require repeated treatment with ivermectin over a period of years. [emedicine.medscape.com]

  These reactions may present as an exacerbation of the local lymphatic signs or general symptoms arising a few hours after the first intake, for instance, fever, headaches, diffuse pain, pruritus and urticaria. [therapeutique-dermatologique.org]

• Erythema

  Infected individuals develop intense pruritus between 30 minutes and 24 hours after the test, which can then be accompanied by erythema, edema, and papular dermatitis. The presence of M streptocerca may cause false-positive reactions. [emedicine.medscape.com]

• Swelling of the Scrotum

  People with the disease can suffer from lymphedema and elephantiasis and in men, swelling of the scrotum, called hydrocele. Lymphatic filariasis is a leading cause of permanent disability worldwide. [cdc.gov]

  In men, elephantiasis can also result in the swelling of the scrotum (hydrocele). Elephantiasis affects the poorest communities, preventing individuals from living a productive working and social life, further trapping them in the cycle of poverty. [unitingtocombatntds.org]

  In men, lymphedema of the genitalia usually involves swelling of the scrotum, often to the size of a watermelon making it very painful and difficult to walk. In women, the condition may present swelling in one or both breasts. [end.org]

• Hematuria

  […] blood, had no recent history of illness, were not pregnant, had not received previous treatment with diethylcarbamazine or albendazole, had no clinically significant biochemical or hematologic abnormalities and had no clinically significant proteinuria, hematuria [healio.com]

  Hematuria and proteinuria may also be present and can eventually cause nutritional deficiencies and anemia. [physio-pedia.com]

  Extralymphatic signs include chronic microscopic hematuria and proteinuria and mild polyarthritis, all presumed to result from immune complex deposition. [merckmanuals.com]

  Hematuria and/or proteinuria can also occur when there is renal involvement. The exact mechanism for this is unknown. Diagnosis can be made with a blood smear. [symptoma.com]

  had no recent history of illness, were not pregnant, had not received previous treatment with diethylcarbamazine or albendazole, had no clinically significant biochemical or hematologic abnormalities, and had no clinically significant proteinuria, hematuria [nejm.org]

Diagnosis can be made with a blood smear. The microfilariae that cause lymphatic filariasis circulate in the blood at night; therefore blood draw should be performed at night. The smear is stained with Giemsa or hematoxylin and eosin and microscopically evaluated for the worm.

Blood tests that detect antigens for the parasites are also available as a diagnostic tool. Circulating antigen detection assay (CFA assay) has been developed for diagnosis of W. bancrofti infections. This test detect antigens released by adult worms, in addition to microfilariae, and therefore can be performed at any time of the day.

There are two commercially CFA tests available for detection of W. bancrofti: Og4C3 ELISA assay which gives an actual count (quantative measure) of adult worms in the body; and TropBio ELISA test that gives only a positive or negative (qualitative) result [5].

Imaging: Ultrasound can be used to detect presence of adult worms in lymphatic vessels. A scan that is positive for the disease shows as a “filarial dance sign” indicating movements of the worms in blood [6].

• Wuchereria Bancrofti

  Elephantiasis due to Wuchereria bancrofti Infection due to Wuchereria bancrofti Lymphadenitis due to Wuchereria bancrofti Lymphangitis due to Wuchereria bancrofti Wuchereriasis ICD-9-CM Volume 2 Index entries containing back-references to 125.0 : [icd9data.com]

  In India, filariasis is predominantly caused by a species of nematode called Wuchereria bancrofti. The disease is transmitted through the bite of blood sucking mosquitoes. [ncbi.nlm.nih.gov]

  Da Wikimedia Commons, l'archivio di file multimediali liberi Jump to navigation Jump to search Lymphatic Filariasis is a parasitic and infectious tropical disease, caused by the thread-like parasitic filarial worms, Wuchereria bancrofti, Brugia malayi [commons.wikimedia.org]

  The aim of this study was to determine whether a similar regimen would also show efficacy against Wuchereria bancrofti. [doi.org]

• Brugia Malayi

  The effect of diethylcarbamazine on Brugia malayi and Brugia pahangi in domestic cats. Annals of Tropical Medicine and Parasitology 53, 394 – 399. El Setouhy, M., Reda, M. R., Ramzy, R. M., Ahmed, E. S., Kandil, A. M., Hussain, O., Farid, H. [doi.org]

  Da Wikimedia Commons, l'archivio di file multimediali liberi Jump to navigation Jump to search Lymphatic Filariasis is a parasitic and infectious tropical disease, caused by the thread-like parasitic filarial worms, Wuchereria bancrofti, Brugia malayi [commons.wikimedia.org]

  Wuchereria bancrofti, Brugia malayi, and Brugia timori, categorized as nematodes, are responsible for causing lymphatic filariasis. [ncbi.nlm.nih.gov]

• Acanthocheilonema Perstans

  Other forms of filariasis are caused by Acanthocheilonema perstans and Mansonella ozzardi and are not in most cases associated with specific symptoms. The prevention of filariasis relies heavily on insecticides and insect repellents. [britannica.com]

• Tissue Nematode

  Filariasis is a parasitic disease caused by tissue nematodes. Lymphatic filariasis can be asymptomatic, where infected people have no symptoms and never will develop symptoms. Other people that are infected will present with acute clinical symptoms. [symptoma.com]

Medications

Persons currently infected with the parasite are treated with diethylcarbamazine (DEC) 6 mg/kg for 12 days irrespective of clinical symptoms [7]. DEC kills the adult worms and therefore ultimately decreases the microfilarial burden. DEC should be avoided in pregnancy and lactation [8].

Doxycycline is sometimes given in addition to DEC (200 mg/d for 4 to 6 weeks) as it has demonstrated macro filaricidal activity and reduces pathology in mild and moderate diseases [9].

DEC is contraindicated in patients as it can worsen onchocercal eye disease. In patients with loiasis, DEC can cause serious adverse reactions such as encephalopathy and death. In such patients doxycycline should be used [10].

Treatment of symptoms (while being treated medically, with DEC or doxycycline) include: lymphedema and acute inflammatory episodes can be relieved using hygiene care, skin care, exercise and most importantly, elevation of the limb affected. Surgery can provide relief from hydrocele.

Early cases have a good prognosis if properly treated. Cases identified in the late stages have a poor prognosis. Prevention Avoidance of mosquito bites by use of mosquito nets or repellents. [webhealthcentre.com]

Treatment and prognosis Treatment options include diethylcarbamazine (DEC) 6mg/kg body weight in combination with albendazole. Complications Grossly dilated lymphatics and edema progressing to elephantiasis . [radiopaedia.org]

In such cases, the prognosis is good. [dovemed.com]

Prognosis The outlook is good in early or mild cases, especially if the patient can avoid being infected again. The disease is rarely fatal, and with continued WHO medical intervention, even gross elephantiasis is now becoming rare. [medical-dictionary.thefreedictionary.com]

The life cycle of the filariasis starts with introduction of larvae injected into human skin by a mosquito bite. The larvae migrate through the mosquito bite wound and enter local lymphatic vessels.

Over nine months, the larvae develop into mature adult worms. The adults male and female worms mate and produce sheathed microfilariae. The microfilariae migrate into lymph and enter the blood stream. When a mosquito bites an infected individual, it ingests the microfilariae and transmits to another human when it bites him/her.

There are three different filarial species that can cause lymphatic filariasis in humans:

• Wuchereria bancrofti (W. bancrofti) – only affects humans
• Brugia malayi (B. malayi) – affects both humans and animals
• Brugia tmori (B. tmori) – affects both humans and animals

Geographic distribution: Most of the infections in the world are caused by the species: Wuchereria bancrofti. Brugia malayi and Brugia tmori are seen primarily in Asia. It is estimated that more than 120 million people worldwide, in 73 countries are infected.

More than 90% of the infections are caused by W. bancrofti species. In the United States (US), Charleston South Carolina was the last known place with lymphatic filariasis episode. The infection has been eradicated in the US [1].

Age: Lymphatic filariasis is most likely first acquired in childhood, but a third of children remain asymptomatic until 5 years of age. The prevalence of this disease in endemic communities increases with age. In endemic areas, most people have been exposed by 40 years of age.

The pathogenesis of the disease is impacted by several factors such as the extent and duration of exposure to infective insect bites, the quantity of accumulating adult worm antigen in the lymphatic system and the host immune response.

Clinical presentation in exposed persons also depends on a number of host and parasite factors, such as: timing of the first exposure to the parasite, the species of filarial pathogen involved, the intensity of exposure to infected mosquitoes, prenatal sensitization [2]. Genetics may also influence clinical presentation (lymphedema tends to occur in families).

Later in infection, immune responses to parasite antigens are down regulated with suppression of T-lymphocyte proliferation (which results in impaired production of Th1 and Th2, and thus cytokines), therefore contributing to this infection becoming a chronic infection.

The best way to prevent filariasis is to avoid mosquito bites.

Filariasis is a parasitic disease that is caused by nematodes (round worms) that inhibit the lymphatic system and subcutaneous tissues of humans and animals. These are thread-like worms that live in the human lymph system. The infection is transmitted human to human by mosquitos. Lymphatic filariasis is a major cause of disfigurement and disability in endemic areas. For example, people with the disease can have lymphedema and elephantiasis and in men scrotum swelling.

Filariasis is a parasitic disease that is caused by nematodes (round worms). These are thread-like worms that live in the human lymphatic system. Some types of filariasis can be transmitted to both animals and humans by mosquitoes. However the most common type (Wuchereria bancrofti) is transmitted only to humans by mosquitos.

Lymphatic filariasis is a major cause of disfigurement and disability. For example, people with the disease can have lymphedema and elephantiasis and in men scrotum swelling.

Who is at risk?

People who live in tropical and subtropical areas in the world (e.g. Asia, Africa, the Western Pacific, and parts of the Caribbean and South America) are at risk. Most of the infections are caused by the species Wuchereria bancrofti. It is estimated that more than 120 million people worldwide, in 73 countries are infected [11]. W. bancrofti species can only infect humans (unlike the other 2 species which can affect both humans and animals).

There are currently no cases of this disease in the United States.
Both men and women are affected equally. The rate of infection increases with age (in particular during childhood and teenage years).

How is the disease transmitted?

A mosquito bites an infected person and then transmits the disease when it bites another person. When the mosquito bites an infected person, the mosquito becomes infected with microfilariae (larvae, or baby worms).

Then when the mosquito bites another person, the microfilariae are deposited on the skin and enter the human’s body. The microfilariae travel to the lymphatic vessels, where they develop into adult worms. Adult worms mate and produce more microfilariae. The cycle repeats until a person is treated.

What are the symptoms of Filariasis?

Some infected people have no symptoms. They are called “carriers”. The infection can be detected using blood smears (drop of blood is placed on a slide, stained with a special dye and looked at using a microscope).
For those who have symptoms:

• Acute adeno-lymphangitis (ADL) – symptoms include: painful lymphadenopathy in the groin or axilla (armpits). The areas are painful, tender, red and swollen and can also become infected with bacteria (secondary infection).

• Acute filarial lymphangitis (AFL) – This is caused by dying adult worms in a human body, either spontaneously or due to treatment. Small tender nodules appear at the site of the worms death. There is NO fever.

• Chronic infections – When lymphatic filariasis develops into a chronic condition (untreated for a long time), it leads to lymphedema (tissue swelling), elephantiasis (severe swelling with skin/tissue thickening), and hydrocele (scrotum swelling)

• Tropical pulmonary eosinophilia – This is caused by an immune hyper-responsiveness to the microfilariae trapped in the lungs. The “classic” presentation is: cough and fever (particularly at night), fever, shortness of breath, weight loss, fatigue.

What tests can be done to check for the disease?

Blood tests can be performed to check for infection: blood smears, immunological tests that are designed to check for chemicals in your body that are specific to filariasis.

Urinalysis can be performed to check for chyluria and for the microfilariae (under a microscope).
Ultrasound test can also be used to look at certain lympatic areas to detect adult worms.

How can filariasis be treated?

Your doctor can prescribe medications to treat this disease. Common medications used are diethylcarbamazine (DEC) and doxycycline. Symptoms can be alleviated by maintaining good hygiene and keeping the affected body part elevated. A hydrocele can be alleviated by surgery.

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