The Stigma of Swelling
Measuring the ups and downs of fluid retention could help millions cope with filarial lymphedema.
Mike Weiler, Lymphatech
Lymphatic filiariasis, often called elephantiasis, is a mosquito-borne parasitic disease endemic in many parts of the world. The parasite, a nematode worm, sets up shop in the lymph system and releases millions of its larvae into the blood. Most cases are asymptomatic, but the infection can still cause long-term damage to the immune system, so that even a passing bacterial or viral infection can trigger the fluid retention and swelling known as lymphedema.
Since 2000, the World Health Organization has treated millions of people with drugs that reduce the larval load and drastically lower disease transmission. But those already infected may suffer lifelong debilitation from swollen limbs, usually the legs. Not only is this uncomfortable, but it also causes public stigma, loss of income, and severe emotional distress. Reducing these adverse consequences requires ongoing monitoring of changes in the volume and circumference of swollen limbs.
To make this monitoring easier, an Atlanta-based biotech company called LymphaTech has developed a portable 3-D infrared scanner. The scanner connects with a tablet computer that processes the measurements and produces a 3-D image.
Researchers from the University of Ruhune in Sri Lanka teamed up with LymphaTech scientists and scientists from the Washington University School of Medicine and Georgia Institute of Technology to test the infrared scanner against existing monitoring technologies. These include water displacement, tape measurements taken by hand, and ultrasound imaging, all of which have limitations ranging from test subject discomfort to inaccuracy and cumbersome equipment unsuited to fieldwork.
The LymphaTech scanner compared very favorably with existing methods, taking only about two minutes to complete an accurate scan, the researchers reported this month in the American Journal of Tropical Medicine and Hygiene. Because it is easily portable, it can be used in remote or poorly equipped locations. The team believes it could be useful both in clinical trials and in routine care. Patients may even feel more motivated to keep up with treatment exercises if they can track subtle changes in their swollen limbs, according to the researchers.