|Lymphatic Filariasis (Elephantiasis)|
|Recently we have been receiving many inquiries related to a national eradication programme of Lymphatic Filariasis ( LF), a chronic condition that can result in Elephantiasis. This is an advanced stage of the illness whereby body parts such as the limbs and the genitals can become irreversibly swollen due to disturbed drainage of the lymph vessels in the skin.
In this health topic we wish to give you some background information on Lymphatic Filariasis and the reasons for the campaign going on in Tanzania at the moment.
However it should be borne in mind that LF is very rare in expatriates. In almost 20 years of treating patient in both rural and urban Tanzania we have seen many Tanzanian patients with LF and Elephantiasis, but have never diagnosed the condition with absolute certainly in expatriates. As the infection can be asymptomatic during a long period of time awareness of the illness is certainly important.
At the IST Clinic we have been participating in a field trial to test a filariasis rapid test. Within our designated test population; expatriates who have been living in Dar es Salaam for more than one year, we have yet to find a positive test result.
We also often test for filariasis when we encounter unexplained allergic reactions or find a high level of eosinophile white cells in a white blood count test. Eosinophiles are a certain type of white cell that can increase when the body is harboring certain parasites like worms and filariasis.
So although we are aware of LF and often test for it when we encounter unexplained allergic type symptoms, we can offer a level of reassurance that the average expatriate or Tanzanian of a higher socio-economic standard does not run a high degree of risk to become infected with LF.
In recent years it has become clear that visitors, such as refuges and longer term soldiers/peace keepers, to highly endemic LF areas can develop a so-called “Expatriate Syndrome”.
Instead of developing the commonly described chronic clinical manifestations of their filarial infections, individuals who have grown up outside of the endemic regions and then moved to these regions and acquired a filarial infection manifest prominent signs and symptoms of inflammatory (including allergic) reactions to the mature or maturing parasites. In LF they have usually been inflammations to lymph glands and lymph vessels, genital pain (from inflammation of the associated lymphatics), along with hives, rashes and other ‘allergic-like’ manifestations, including blood eosinophilia. The reason for these different clinical presentations lies almost certainly in the different immune response of a person who has had no prior exposure to LF.
Given the fact that LF can fail to show symptoms during the first years after infection, and the fact that infections can originate in childhood, we do take the LF risk seriously and if you have any queries or concerns regarding LF, please come to see one of the IST doctors for advice and if necessary testing.
Here follows a general description of the disease and the campaign to eradicate LF.
Lymphatic Filariasis, known as Elephantiasis, puts at risk more than a billion people in more than 80 countries. Over 120 million have already been affected by it, over 40 million of them are seriously incapacitated and disfigured by the disease. One-third of the people infected with the disease live in India, one third are in Africa and most of the remainder are in South Asia, the Pacific and the Americas. In tropical and subtropical areas where lymphatic filariasis is well-established, the prevalence of infection is continuing to increase. A primary cause of this increase is the rapid and unplanned growth of cities, which creates numerous breeding sites for the mosquitoes that transmit the disease.
In its most obvious manifestations, lymphatic filariasis causes enlargement of the entire leg or arm, the genitals, vulva and breasts. In endemic communities, 10-50% of men and up to 10% of women can be affected. The psychological and social stigma associated with these aspects of the disease are immense. In addition, even more common than the overt abnormalities is hidden, internal damage to the kidneys and lymphatic system caused by the filariae.
Signs and symptoms
The worst symptoms of the chronic disease generally appear in adults, and in men more often than in women. In endemic communities, some 10-50% of men suffer from genital damage, especially hydrocoele (fluid-filled balloon-like enlargement of the sacs around the testes) and elephantiasis of the penis and scrotum. Elephantiasis of the entire leg, the entire arm, the vulva, or the breast – swelling up to several times normal size – can affect up to 10% of men and women in these communities.
Acute episodes of local inflammation involving skin, lymph nodes and lymphatic vessels often accompany the chronic lymphoedema or elephantiasis. Some of these are caused by the body’s immune response to the parasite, but most are the result of bacterial infection of skin where normal defenses have been partially lost due to underlying lymphatic damage. Careful cleansing can be extremely helpful in healing the infected surface areas and in both slowing and, even more remarkably, reversing much of the overt damage that has occurred already.
In endemic areas, chronic and acute manifestations of filariasis tend to develop more often and sooner in refugees or newcomers than in local populations continually exposed to infection. Lymphoedema may develop within six months and elephantiasis as quickly as a year after arrival.
Treating the individual.
Who’s strategy to eliminate lymphatic filariasis & personal prevention
To interrupt transmission, districts in which lymphatic filariasis is endemic must be identified, and then community-wide (“mass treatment”) programmes implemented to treat the entire at-risk population. In most countries, the programme will be based on once-yearly administration of single doses of two drugs given together: albendazole plus either diethylcarbamazine (DEC) or ivermectin, the latter in areas where either onchocerciasis or loiasis may also be endemic; this yearly, single-dose treatment must be carried out for 4-6 years.
Avoiding mosquito bites is another form of prevention. The mosquitoes that carry the microscopic worms usually bite between the hours of dusk and dawn. If you live in an area with lymphatic filariasis:
Economic and social impact
Ype Smit , January 2008