“Elephantiasis… drew the attention of the physicians and laymen from early times on account of the often grotesque and horrible disfigurement of the patient” (Hoeppli, 33).
Lymphatic filariasis, or elephantiasis, is one of those diseases that manages to convey both its best known symptom and its special horror in a single word: its common name. Elephantiasis. Limbs as thick and gnarled as three trunks, a scrotum so enlarged that it has to be carried around in a wheelbarrow, dreadfully swollen heavy breasts.
That’s what elephantiasis is, but when it’s caused by parasites – worms living in the lymph vessels – the underlying infection is lymphatic filariasis. This is a disease of the tropics: Africa, much of Asia, Australia and islands in the Pacific, even parts of South America and the Caribbean. It is transmitted by mosquitoes.
|This map shows areas of the world where lymphatic filariasis had a|
severe impact in 2004. The darker the colour, the greater the impact.
Map by Lokal_Profil CC BY-SA 2.0
Asymptomatic Lymphatic Filariasis
Many people who harbour filarial worms never have any symptoms. Fetal exposure to the worm antigens in infected women appears to result in some level of tolerance in children.
It’s thought that elephantiasis only develops after many years and repeated infection; thus, though children are infected at an early age in areas where the disease is found, symptomatic lymphatic filariasis is a disease of adults.
Acute Lymphatic Filariasis
Researchers are not sure what causes an asymptomatic infection to progress to inflammation of the lymph vessels and lymph nodes, fever and chills, and swelling of tender affected limbs. It may be the death of the adult worms, which live for perhaps a decade. At this stage, bacteria are present in inflamed tissues, and these may originate from the victims skin or from the worms themselves: filarial worms are known to carry symbiotic bacteria that the human immune system reacts to.
The acute phase often also brings enlargement and inflammation of the testes, however symptoms typically subside in about a week.
The slide toward elephantiasis begins when the lymph vessels become enlarged and blocked as a result of the presence of adult worms. Lymph accumulates in the tissues instead of flowing through the vessels back to the bloodstream, and permanent swelling occurs with thickening and folding of the skin. Scar tissue forms, the urine becomes milky with lymph fluid, and bacterial infection is common.
Interestingly, when visitors to an affected region acquire the infection the immune response is different because they have not been exposed since infancy. For these people, symptoms may include inflammation of the lymphatic system that waxes and wanes over many years.
Roberts and Janovy point out that the name elephantiasis is nonsense, since it literally means “a disease caused by elephants!” I suppose, however, that if it seemed like you were turning into an elephant, the name would seem about right.
Hoeppli, R. Parasites and Parasitic Infections in Early Medicine and Science. University of Maylaya Press, 1959.
Hotez, Peter J. Forgotten People, Forgotten Diseases. Washington: ASM Press, 2008, 39 – 47.
Roberts, Larry S., and John Janovy Jr. Gerald D. Schmidt & Larry S. Roberts’ Foundations of Parasitology 8th ed. Boston: McGraw Hill, 2009, 463 - 468.