Featured Research

from universities, journals, and other organizations

Antibiotics Help Combat Dangerous Tropical Disease

June 27, 2005
University of Bonn
An antibiotic which has long been used to fight infections of the respiratory tract and intestine also seems to be able to defeat the dangerous pathogens causing elephantiasis. This is proved by a study carried out by parasitologists from the University of Bonn together with colleagues from Hamburg, Liverpool and Tanzania. Their findings have been published in the prestigious medical journal The Lancet (vol. 365, May 2005). The disease has previously been usually incurable.

Wuchereria worms under the microscope. (Copyright (c) Sabine Wand)

The disease is triggered off by the bite of an infected mosquito: together with its anticoagulant the mosquito pumps threadworm larvae into its host's body. These gravitate towards the lymph nodes, where they grow into threadworms which may be up to ten centimetres long. The body reacts by producing inflammation which halts the flow of lymphatic fluid. The consequence of this is that arms, legs and genitals swell to monstrous proportions – hence the name elephantiasis. More than 120 million people worldwide are infected with the pathogen wuchereria bancrofti.

Related Articles

Adult wuchereria worms have a lifespan of up to five years. During this time they produce millions of offspring, what are known as micro-filariae, each of them smaller than the full stop at the end of this sentence. If the host is bitten again by a mosquito, the micro-filariae are ingested together with the blood. Inside the insect they mature into infectious worm larvae, thereby completing the circle.

'Although the drugs currently in use kill the micro-filariae, they largely leave the adult worms unscathed,' Bonn parasitologist Professor Achim Hörauf explains. 'Due to the long lifespan of the wuchereria worms, therapy lasts several years, during which time the symptoms continue to persist.' What is more, the drugs may cause severe side-effects.

De-worming the roundabout way

Yet the threadworm, too, has a sub-tenant, and this may be its Achilles heel, since in each wuchereria worm there are specific bacteria which are absolutely indispensable to the parasite's survival. If these bacteria die, the parasite will also die sooner or later. 'This is why wuchereria is susceptible to antibiotics which are normally used against bacterial infections,' Professor Hörauf emphasises. One example is doxycyclin, which has been used for decades for infections of the respiratory tract and the gastro-intestinal tract.

In their study the medical experts in Tanzania treated 72 male patients for eight weeks with doxycyclin or a placebo. Initially the patients' blood was swarming with micro-filariae: the researchers counted up to 1,300 of them per millilitre of blood. Eight months later they had almost completely disappeared; only in one patient were sporadic micro-filariae still detected. However, the proportion of micro-filariae also dropped in the placebo group – an effect which was probably due to the improved care given the test persons.

Unlike the drugs in use up to now the antibiotic also killed off the adult worms. Fourteen months after being treated with doxycyclin the doctors were only able to detect the typical movements of the worms ('the dance of the filariae') on ultrasound in one in five patients. In the placebo group the rate was 89%. In the doxycyclin group the concentration of specific worm proteins in the blood fell by over half.

Effective, cheap, few side-effects

'The importance of these findings for therapy should not be underestimated,' Professor Hörauf emphasises. 'The mature worms are after all responsible for such symptoms of the disease as the extreme swelling of the limbs. In the past there was no effective and reliable method of combating them.' The effectiveness of the antibiotic might be even greater than what was measured: 'We cannot exclude the possibility that several patients became re-infected in the months following treatment with doxycyclin. It is therefore quite possible that all the worms were killed and the remaining 20% are the result of re-infection which would no longer occur if infection was effectively prevented.

Doxycyclin has been used for many years and has only minor side-effects. However, in young children it may cause irreparable damage to the teeth and slow down growth of the bones. For this reason the antibiotic should not be used during pregnancy, either. For adolescents and adults, however, the drug is harmless. Moreover, it is comparatively cheap. 'Its biggest advantage is that it is already licensed for medical use,' Professor Hörauf points out. 'Elephantiasis hits the poor most of all. It is therefore not likely that the pharmaceuticals industry will develop completely new drugs.'

Story Source:

The above story is based on materials provided by University of Bonn. Note: Materials may be edited for content and length.

Cite This Page:

University of Bonn. "Antibiotics Help Combat Dangerous Tropical Disease." ScienceDaily. ScienceDaily, 27 June 2005. <www.sciencedaily.com/releases/2005/06/050624101256.htm>.
University of Bonn. (2005, June 27). Antibiotics Help Combat Dangerous Tropical Disease. ScienceDaily. Retrieved March 28, 2015 from www.sciencedaily.com/releases/2005/06/050624101256.htm
University of Bonn. "Antibiotics Help Combat Dangerous Tropical Disease." ScienceDaily. www.sciencedaily.com/releases/2005/06/050624101256.htm (accessed March 28, 2015).

Share This

More From ScienceDaily

More Health & Medicine News

Saturday, March 28, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

These Popular Antibiotics Can Cause Permanent Nerve Damage

These Popular Antibiotics Can Cause Permanent Nerve Damage

Newsy (Mar. 27, 2015) — A popular class of antibiotic can leave patients in severe pain and even result in permanent nerve damage. Video provided by Newsy
Powered by NewsLook.com
House Ready to Pass Medicare Doc Bill

House Ready to Pass Medicare Doc Bill

AP (Mar. 26, 2015) — In rare bipartisan harmony, congressional leaders pushed a $214 billion bill permanently blocking physician Medicare cuts toward House passage Thursday, moving lawmakers closer to resolving a problem that has plagued them for years. (March 26) Video provided by AP
Powered by NewsLook.com
What's Different About This Latest Ebola Vaccine

What's Different About This Latest Ebola Vaccine

Newsy (Mar. 26, 2015) — A whole virus Ebola vaccine has been shown to protect monkeys exposed to the virus. Here&apos;s what&apos;s different about this vaccine. Video provided by Newsy
Powered by NewsLook.com
HIV Outbreak Prompts Public Health Emergency In Indiana

HIV Outbreak Prompts Public Health Emergency In Indiana

Newsy (Mar. 26, 2015) — Indiana Gov. Mike Pence says he will bring additional state resources to help stop the epidemic. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins