Filariasis

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Filariasis is an infection caused by microscopic, thread-like worms called filarial worms. This parasitic disease is transmitted to people through the bite of an infected mosquito which develops into adult worms in the lymphatic vessels. It causes great damage and overwhelming swelling known as lymphoedema. Elephantiasis is a condition characterized by painful, distorting swelling of the legs and genital organs. This is the typical sign of filariasis in its late-stage.

Filarial parasites affect the lives of millions of people, especially those who live in tropical countries. The World Health Organization (WHO) conducts annual treatment of all individuals at risk particularly people living in endemic areas.

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Signs and symptoms

Some infected people are asymptomatic and do not develop clinical symptoms. Only a small percentage of people develop lymphedema which is a result of improper functioning of the lymph system that lead in fluid collection and swelling. Legs are the most affected but it can also manifest in the arms, breasts, and genitalia. Some people suffering from the disease only find out about it years after being infected.

The lymph experiences swelling while the function of the lymph deteriorates. As a result, the body finds it hard to safeguard itself from germs and infections. Increased bacterial infections in the skin and lymph system causes the skin to harden and thicken. This condition is called elephantiasis. Men can develop hydrocele or swelling of the scrotum once an adult worm dies inside.

Filarial infection can lead to pulmonary tropical eosinophilia syndrome which is characterized by cough, shortness of breath, and wheezing. The eosinophilia also manifests high levels of IgE (Immunoglobulin E) and antifilarial antibodies.

Causes and risk factors

When a mosquito bites a person infected with lymphatic filariasis (LF), microscopic worms that are circulating in that person’s blood will infect the mosquito. Another person can get lymphatic filariasis upon being bitten by an infected mosquito. The microscopic worms will pass from the mosquito penetrating the skin. It will travel to the lymph vessels and stay there until they mature.

Meanwhile, the person bitten by the infected mosquito has no idea that worms are living inside his body. The adult worm may live between 5 to 7 years. The adult worms are capable of mating and releasing microscopic worms into the blood system.

The disease may cause permanent long-term disability. It could drastically affect the lifestyle and productivity of a person due to persistent pain and inability to move normally.

Diagnosis and tests

The most effective way to determine if a person is infected by lymphatic filariasis is through a blood test. Observations from most parts of the world indicate that the parasites have a "nocturnal periodicity". It means that the parasites can be effectively detected in the blood during the hours of 10 p.m. to 2 a.m.. Most laboratory blood examinations are taken during this time period when microfilaria are most common in peripheral blood. Blood specimens taken at night can be tested by filtration or concentration techniques. A simpler and more specific antigen-detection test called immunochromatographic test (ICT) is now available. ICT can detect infection in a matter of minutes and unlike other tests. It is not time sensitive and can be performed any time of day.

Treatment

There is no single drug or treatment that is effective for all filariasis cases. But all patients are advised to consider these three simple issues:

Anti-parasitic Drug Therapy. This treatment prevents possible transmission of LF to other people. Infected individuals are treated with a series of anti-parasitic drugs.

Supportive Clinical Care.

  • Lymphoedema management. The patient is advised to follow these simple procedures. These simple measures can improve elephantiasis condition over time:
    • Wash affected areas of the body twice daily with soap and clean, cool water. Dry the said areas with care.
    • Raise the affected limb during the evening.
    • Conduct regular exercises for the affected limb.
    • Wear comfortable shoes.
    • Keep nails and spaces between the toes clean.
    • Apply medicated creams or antibiotics on small wounds or cuts.
  • Hydrocele surgery. Surgery is a treatment option for most hydrocele patients. Early hydrocele and corrective surgery can be done with local anaesthetic. However, other genital damage may require more complicated surgery. In reality, hydrocele surgery is often seen as an expensive treatment for people with LF.

Patient education and counselling. Psychological counselling is also important in helping patients with LF-induced disability. Physical treatment is vital but emotional support can be very significant in dealing with shame, isolation, sexual dysfunction, intense chronic pain and suffering.

Possible complications

Among the common complications of lymphatic filariasis are:

  • hardening and thickening of the skin
  • bacterial infections affecting the skin and lymph system
  • disfigurement of affected body parts
  • inability to have sex

Prevention and control

A person can avoid developing lymphatic filariasis by:

  • Taking medicine that is capable of killing microscopic worms that cause LF.
  • Controling mosquito population.
  • Using mosquito repellent on the skin.
  • Using a mosquito net at night.

Cases in the Philippines

Filariasis is endemic in 44 provinces in the Philippines. WHO estimated that 200,000 cases of LF in the country with around 22 million Filipinos at risk.

In 2009, the WHO and DOH declared the provinces of Sorsogon and Southern Leyte to be free from LF. More recently, Biliran has also been declared LF free. Awareness programs are being conducted in communities and schools to prevent LF.


Congratulations, Southern Leyteños!

The Department of Health (DOH) officially declared Southern Leyte as the first filaria-free province in the Philippines.

"After seven consecutive years of mass drug administration and support from our partners from the World Health Organization, Glaxo-SmithKline, Department of Education and especially the local government's health workers, we are celebrating this milestone to show the world that filariasis can be beaten," Health Secretary Francisco T. Duque III announced.

The health chief disclosed that the elimination of filariasis in Southern Leyte was in response to the 1997 World Health Assembly which urged member states, including the Philippines, to strengthen activities toward eliminating lymphatic filariasis (LF) as a public health problem and to President Gloria Macapagal-Arroyo's call to establish a National Program for Eliminating Filariasis.

The declaration of Southern Leyte as a filaria-free province is in accordance with the elimination criteria namely: that sentinel surveillance must show less than 1% prevalence of microfilaremia in identified and selected areas, no true positives in the 2-4 years old children tested, and that no positives among the 3,000 new school entrants. According to Duque, all 18 rural health units (RHU's) and two city health units simultaneously implemented the mass drug administration from 2001 until 2007. Local government units committed in providing transportation expenditures and provided drugs for the program and conducted continuous advocacy.

The benchmark set by the DOH National Filariasis Elimination Program was 85% coverage of all eligible population. However, Southern Leyte surpassed the standard and accomplished 88.90% in 2001, 89.0% in 2002, 88.5% in 2003, 87.83% in 2004, 90.0% in 2005, 90.50% in 2006, and 90.90% in 2007.

Lymphatic Filariasis (LF) or Elephantiasis is a parasitic disease transmitted by mosquitoes that affects the world's poorest countries. In the Philippines, filariasis is endemic in 40 provinces, in which 76% of cases can be found in 4'h to 6 1h class municipalities. If left untreated, more than 23 million Filipinos are at risk of getting infected.

After the Southern Leyte's declaration, Duque stressed that the challenge now is to sustain the province's status. The Filariasis Technical Working Group recommends the strengthening of surveillance in all borders of the provinces, conduct orientation of health workers in detecting and managing filariasis, conduct consultative meetings with neighboring endemic provinces to set agreement on LF surveillance, and strengthen routine surveillance within the province in order to refer any suspected case to the nearest RHU as soon as possible.

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