
As you walk on the streets in Vellore, you will most likely see a person such as the man above, with an enlarged, edematous lower extremity, which is a common manifestation of a condition called elephantiasis or lymphatic filariasis. According to the World Health Organization, over 120 million have been infected and a third of those infected live in India.

The cause of this infection is due to the thread-like, parasitic filarial worms (
Wuchereria bancrofti, Brugia malayi and Brugia timori) that multiply and circulate in the lymphatic system causing obstruction of the fluid secondary to the inflammation produced as a defense mechanism against the worms. These worms are transmitted by mosquitoes which ingest the microfilariae circulating in the blood of an infected human. The microfilariae develop into larvae and are then passed to other humans when the infected mosquitoes bite them. This type of infection is common in underdeveloped countries such as India, due to the rapid and unplanned growth of cities, thus creating breeding grounds for the type of mosquitoes that transmit these worms (3). The mosquitoes that act as vectors are usually from the following scientific genera: Anopheles, Aedes, Culex and Mansonia. It is known that
W. bancrofti is mainly transmitted by the Anopheles genus and
B. malayi transmitted by the Mansonia genus. Infection usually occurs due to a large number of microfilariae, and thus many infective bites are required to reach that number. Therefore, those people living in areas endemic to this infection are more likely to become infected versus people traveling to the endemic countries for a short period of time (1).
People usually become infected as children; yet don't start manifesting symptoms until adulthood. Signs and symptoms vary from person to person and are different in the acute and chronic settings. Acutely, a patient may have three main symptoms of fever, lymphangitis and lymphadenitis. The fever is usually called "filarial" or "elephantoid" fever and is known to be immune-mediated in nature. Lymphangitis, or inflammation of channels within the lymphatic system, is typically seen in the extremities or genital regions, accompanied by erythema and edema along the channels. Lymphadenitis, or the development of nodules in the lymph node areas, is due to collection of the worms within the lymph nodes and lymph vessels. Though some patients present with acute symptoms, others infected with the microfilariae have no obvious symptoms and are known to be infected only because of the levels of the microfilariae in their blood. This will then put them at a higher risk of developing the chronic symptoms (1).
Chronic symptoms of filariasis are more of what I saw while in India. As mentioned before, it most likely appears in adulthood and more often in men than women. A hydrocele is a common example of a chronic manifestation and is due to the high numbers of worms found in lymph vessels around the scrotal area. Lymphedema is also a sign of chronic infection and includes the development of edematous extremities secondary to the collection of lymph fluid due to the destruction of the lymphatic vessels by the worms. The most debilitating and shocking of the chronic manifestations is elephantiasis, which is thickening of the skin and underlying tissue most commonly in the extremities, genitals and breasts due to the prolonged obstruction of the lymphatic vessels (1). Living with this manifestation can also be a social stigma in these underdeveloped countries secondary to the disfigurement and shame it can cause the infected individual (3).
Until recently has the diagnosis of this infection been available. In the past it could only be detected microscopically with the visualization of the worms. Yet this was a difficult task in itself because these parasites were found to have what scientists call a "nocturnal periodicity", therefore limiting their appearance in the blood to hours around midnight. Now a very specific and sensitive test to detect the filarial antigen is available and can detect whether a person is infected with only a few drops of their blood (3).

In order to completely treat the infection, the worms must be killed in their adult-stage. Albendazole and diethylcarbamazine citrate (DEC) have both been shown to be effective as single therapies or the combination of both albendazole and DEC or albendazole and ivermectin have been shown to be 99% effective (1). Currently it is though that in order to completely stop transmission of the parasite, the combination of drugs must be taken every year for 5 years (2). The treatment can improve the symptoms of lymphatic filariasis, yet progression of the serious symptoms is augmented with secondary infections from bacteria or fungi to the infected extremities (3). Prevention of these secondary infections is an important factor, and education of proper hygiene and care for infected extremities is also necessary for the population with literature that is easy to comprehend such as the above pictorials.
Individual treatment is important to help a particular patient with their symptoms, yet treatment with a community-wide focus is more important in an endemic country such as India. Since the parasite is transmitted by the mosquito vector, using insecticides can help tackle root of the problem. It is also important to halt transmission of the microfilariae from the blood of one infected individual to many other individuals, so treating the masses with the proper regimens, even if the vectors are not controlled, can also play an important factor in elimination. As an example for mass control in other countries where filarial infections are endemic, DEC has been added in small amounts to help control the spread of infection and has shown to be successful (1). In India, the 2006 mass drug administration campaign was delayed a year and began in 2007 with 74,840,000 people being given the combination of albendazole and DEC. Details about the campaign's success are not currently available (4).
In researching this topic, I came across a website called, The Global Alliance to Eliminate Lymphatic Filariasis. This alliance was formed in 2000 with the purpose to eliminate lymphatic filariasis as a public health problem by 202o and to alleviate the hardships of individuals suffering from disability secondary to lymphatic filariasis (2). The alliance has made some dramatic leaps in eliminating filariasis with its implementation of mass drug administration, yet there is still much to be accomplished in order to reach their goal. I feel grateful to have seen this problem in person and now know more about its etiology, symptoms and treatment. I hope to one day hear that this parasite has been eradicated from the world, maybe even during my medical career.
References
1) Hills-Evans, Kelsey. "Lymphatic Filariasis." [Online website.] March 2008. http://www.stanford.edu/class/humbio103/ParaSites2006/Lymphatic_filariasis/index.htm
2) A Future free of LF, Global Alliance. "The Global Alliance to Eliminate Lymphatic Filariasis." [Online website.] March 2008. http://www.filariasis.org/index.htm
3) World Health Organization. Health Topics. "Filariasis." [Online website.] March 2008. http://www.who.int/topics/filariasis/en/
4) World Health Organization, Geneva. Weekly epidemiological record. "Global programme to eliminate lymphatic filariasis." No. 42 (2007): 361-380. http://www.who.int/wer/2007/wer8242.pdf
Images (in the order in which they appear)
"Elephantiasis.gif." Yahoo search of elephantiasis pictures. Retrieved March 10, 2008.
"Life Cycle of Wuchereria bancrofti." Parasites and Health. Filariasis. May 2004. Retrieved March 10, 2008 from http://www.dpd.cdc.gov/dpdx/HTML/Filariasis.htm.
"How can we manage LF?" The Global Alliance to Eliminate Lymphatic Filariasis. 2000. Retrieved March 9, 2008 from http://www.filariasis.org/resources/managelf.htm.
"Microfilaria of Wuchereria bancrofti, from a patient seen in Haiti." Image Library. Filariasis. August 2002. Retrieved March 11, 2008 from http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/Filariasis_il.htm.