Symptoms of Elephantiasis (Lymphatic Filariasis)

“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 8^th ed. Boston: McGraw Hill, 2009, 463 - 468.

Elephantiasis and Wolbachia: The Bacteria Behind the Worms

Horrific parasites sometimes turn out to be mere vessels.

Filarial worms, nematodes that are transmitted by insects and live in the tissues, cause horrible disfigurement, disability, blindness. The common names for the diseases they cause are descriptive and apt: elephantiasis, and river blindness.

Wucheria bancrofti, and Brugia malayi nematode worms live in human lymph vessels. Prolonged presence of the worms there often results in the affected part – often a limb or the scrotum - becoming grossly enlarged and deformed. Microfilaria, the worm’s young, circulate in the blood.

Elephantiasis results in almost
unbelievable disfigurement of
various parts of the body.
Imagine living with this.
Tropenmuseum of the Royal
Tropical Institute (KIT)
CC BY-SA 3.0

Onchocerca volvulus adults live together in nodules in the skin. Their young migrate through the skin and, over the long term, can cause discoloration, aging, and sagging of the skin. Worse, microfilariae in the eyes cause blindness.

For a long time, we thought that the worms themselves, and the microfilariae, caused these terrible responses to infection – that the battle between the human body and the worms caused blindness and disfigurement. But now it’s becoming clear that the real culprit is not the worms, but a type of bacteria living inside the worms. The problem is Wolbachia pipientis.

Wolbachia and Filarial Worms

Wolbachia is best known for living in insects, where it is typically parasitic and sometimes causes fatal disease. In nematodes, the relationship is different. In nematodes, Wolbachia is a symbiont: the bacterium actually provides nutrients to the parasitic worm that the worm can’t otherwise get, and without the Wolbachia, the worm can’t survive.

Researchers now have compelling evidence that what the human immune system responds to is actually the Wolbachia, not the filariae or the microfilariae. It’s the Wolbachia that causes elephantiasis and river blindness.

Wolbachia, Filarial Nematodes’ Achilles Heel

Treatment of the diseases caused by filarial nematodes has proven difficult for many reasons, not the least of which is that few drugs kill the adult worms. The discovery of their reliance on Wolbachia reveals a weakness that may be the worm’s undoing: instead of finding a drug to kill the worms, we can use a drug to kill the Wolbachia.

Ironically, if it’s the Wolbachia that’s actually the culprit, the worms end up as collateral damage.

Pinworms and Human Immunity

Thoughts on pinworm infections...

I had a strongly worded email from someone who had apparently read, and taken exception to, one of my articles about pinworm (Enterobius vermicularis). I was a little surprised by the tone of the email - who knows why someone would become attached to this particular soapbox - but the vehement claim that the human immune system will eradicate a case of pinworm (enterobiasis) got me thinking.

One female pinworm can produce 10,000 sticky eggs.

Mentnafunangann; CC BY-SA 3.0

Will Pinworm Infection Resolve Without Treatment?

I’m of the understanding that a pinworm infection will resolve on its own eventually if left untreated – and I never said otherwise – but what role does the immune system play? Can the immune system kill the adult worms? We know that the immune system responds to parasites, but many parasites are good at evading immune attacks, and prompting moderation of the immune response. Enterobius vermicularis should be particularly good at this because it is one of our heirloom parasites: it’s been with us hundreds of thousands of years.

Add to this the frequently reported problem of reinfestation through swallowing eggs in the home/school environment and one begins to suspect that waiting for the immune system to do the job could be a long process. It’s clear that, for many people, the immune system is ineffective at eliminating the adults (they likely die of old age after a month or so), and unable to effectively kill larvae over the long term after initial exposure.

Having said all that, it probably doesn’t matter all that much, except for those unfortunate individuals that experience bad symptoms.

A Realistic Approach For Pinworm Infection

Further thoughts:

• Texts tell us that the majority of pinworm infections are asymptomatic, so lots of people have pinworms, don’t suffer any unpleasant symptoms, and eventually eliminate the worms on their own. (And if they have no symptoms, they’re less likely to spread it around.)


• The ability to fight off enterobiasis likely varies from one person to the next, as it appears to with other parasitic worm infestations.


• An overzealous approach to eradicating pinworms is probably unrealistic.  They’re so good at spreading themselves around, and we’re so poor at fighting them off, that actually getting rid of them is next to impossible.


• When symptoms are severe and persistent, however, only the most stoic of patients would refuse treatment. I’ve never had the pleasure myself, but I’ve heard first hand accounts that were not pretty.

I suspect most people would choose to treat a pinworm infection but it's up to the individual.