Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Global program to eliminate elephantiasis has early success in Egypt

24.03.2006


Organizers of a 20-year global effort to eliminate a parasitic infection that is a leading cause of disability have an early victory to savor: a five-year Egyptian elimination campaign has mostly succeeded, according to a new report in the March 25 issue of The Lancet. Infection with the parasites, threadlike filarial worms, can lead to the dramatic, disfiguring swelling known as elephantiasis.



Researchers from Washington University School of Medicine in St. Louis and Ain Shams University in Egypt found that after five years of annual mass treatments with two drugs, rates of filarial infection sharply declined in Egypt.

"The parasite’s transmission efficiency is low, so the thinking is that once we get human infection rates below a critical level, remaining infections will die out without further intervention," says senior author Gary Weil, M.D., professor of medicine and of molecular microbiology at Washington University. "Our assessments suggest that the Egyptian campaign to eliminate these infections, which was implemented by the Egyptian Ministry of Population and Health, has achieved its goals in most areas of the country."


Filarial worms are nematodes closely related to the heartworm parasites that infect dogs and cats. Infections with the worms, which are spread by mosquitoes, can lead to lymphatic filariasis, a condition where the worms lodge in lymphatic vessels. This triggers inflammation that blocks the drainage normally provided by the lymphatic system and leads to massive swelling of the legs, known as elephantiasis, and genital deformities, which are called hydroceles.

"In addition to causing disability, the disfigurement created by elephantiasis is often a source of great social stigmatization," Weil notes.

Epidemiologists estimate 120 million people are infected with filarial worms in 83 tropical countries. Of those infected, approximately 40 million have clinical symptoms. As many as 1.2 billion people are at risk of infection with the parasites, which can live and reproduce for several years inside the human body. According to the World Health Organization (WHO), lymphatic filariasis is a leading cause of chronic disability in the world.

Policymakers at World Health Assembly meetings in 1997 endorsed filariasis as a candidate disease for global elimination for several reasons: the worms that cause the disease are inefficiently transmitted, they are not known to infect any species other than humans and mosquitoes, and they are vulnerable to three drugs, albendazole, ivermectin and DEC (diethylcarbamazine).

"The manufacturers of the first two drugs later generously decided to donate the medicines to the global program," Weil says. "The third medicine is not free but is very inexpensive."

The assembly passed a resolution calling for the elimination of filariasis by 2020. The strategy the WHO chose for eliminating the parasite is called mass drug administration (MDA).

"In regions where the parasite is known to be present, you annually give two medications that kill the worms," Weil explains. "With the exception of pregnant women and children under two years of age, these drugs are given to everyone in the region without testing each person for the infection."

Planners estimated that five annual repetitions of the MDA program would be needed to drive parasite infection rates down to levels where the few remaining infections would die off on their own. Egypt became one of the first countries to start a five-year MDA program in 2000, working to reach 2.5 million people in 181 Egyptian localities affected by lymphatic filariasis.

"The drugs are free or inexpensive, but distribution on this scale in rural villages and poor areas is a big, expensive job," Weil says. "Donations from foundations and wealthy countries helped fund the distribution in Egypt, and more of that same support is needed for campaigns in other countries."

Working in collaboration with colleagues at Washington University including William D. Shannon, Ph.D., associate professor of biostatistics and researchers at Ain Shams in Egypt, Weil developed a plan for assessing the degree to which the Egyptian MDA program was successful. Using several different tests, some of which were developed in Weil’s lab, Egyptian scientists annually assessed infection rates during the MDA program in two villages north of Cairo and two villages south of Cairo. Each village has a population of 3,000 to 5,000.

The tests revealed sharply declining infection rates over the course of the MDA program. For example, tests of first graders for an antibody that reveals prior exposure to the parasite declined from 18.2 percent positive prior to MDA to 0.2 percent positive after the fifth round of MDA. A test for infection in mosquitoes also showed infection rates plummeted after MDA.

Two of the four villages studied did not quite achieve elimination targets after 5 years of MDA; they will receive a sixth round of treatments in 2006 to ensure that the parasite is eliminated.

Assessment of the Egyptian campaign’s results was funded as a part of the International Collaborations in Infectious Diseases Research (ICIDR) program at the National Institutes of Health. Weil recently received a new ICIDR grant for an added $5 million over five years for a larger program to assess and follow-up filariasis elimination in Egypt.

"With new collaborators from Erasmus University in Holland and Smith College in Massachusetts, we will work with the Ain Shams University group to monitor 44 Egyptian villages, checking to see if remaining infections die out as expected or if the parasite shows any signs of resurgence," he says. "We’ll also be looking at the goals WHO has set for these programs in terms of how far we need to drive infection rates down: are the current targets too stringent? Would it be helpful to have phased goals?"

Weil notes that the filariasis elimination program, which is now coordinating MDA treatments in 35 nations, has to confront a diverse array of economic, cultural and logistical obstacles.

He praises the Egyptian health ministry’s efforts to increase acceptance of the need to participate in the MDA program, noting that it used approaches such as educational comic books and television advertisements featuring Egyptian celebrities to promote public awareness.

"The world faces many challenges in bringing this kind of MDA campaign to the 83 nations where the parasite is present, but this first assessment of a completed five-year MDA program is very encouraging," Weil says.

Michael Purdy | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht TSRI researchers develop new method to 'fingerprint' HIV
29.03.2017 | Scripps Research Institute

nachricht Periodic ventilation keeps more pollen out than tilted-open windows
29.03.2017 | Technische Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>