“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.
Elephantiasis
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.
Further reading:
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.
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