WHO certifies Kenya free of Dracunculiasis (2 March 2018)

The World Health Organization (WHO) has recently certified Kenya free of Dracunculiasis (Guinea-worm disease).

Background Information:

Dracunculiasis (commonly known as guinea-worm disease) is a crippling parasitic disease caused by Dracunculus medinensis – a long, thread-like worm. It is transmitted exclusively when people drink stagnant water contaminated with parasite-infected water fleas.

It is rarely fatal, but infected people become non-functional for weeks. It affects people in rural, deprived and isolated communities who depend mainly on open surface water sources such as ponds for drinking water.

Scope of the problem

During the mid-1980s an estimated 3.5 million cases of dracunculiasis occurred in 20 countries worldwide, 17 countries of which were in Africa. The number of reported cases fell to fewer than 10 000 cases in 2007. In 2016, only 25 cases were reported globally – one of the lowest in history.

Transmission, life-cycle and incubation period

About a year after infection, a painful blister forms – 90% of the time on the lower leg – and one or more worms emerge accompanied by a burning sensation. To soothe the burning pain, patients often immerse the infected part of the body in water. The worm(s) then releases thousands of larvae (baby worms) into the water. These larvae reach the infective stage after being ingested by tiny crustaceans or copepods, also called water fleas (cyclops).

People swallow the infected water fleas when drinking contaminated water. The water fleas are killed in the stomach but the infective larvae are liberated. They then penetrate the wall of the intestine and migrate through the body. The fertilized female worm (which measures from 60–100 cm long) migrates under the skin tissues until it reaches its exit point, usually at the lower limbs, forming a blister or swelling from which it eventually emerges. The worm takes 10–14 months to emerge after infection.

Ciclo-de-vida-del-gusano-de-Guinea-Cortesia-de-The-Carter-Center-A-Granberg

Image source: https://www.researchgate.net/figure/Ciclo-de-vida-del-gusano-de-Guinea-Cortesia-de-The-Carter-Center-A-Granberg_fig1_312813779

Prevention

There is no vaccine to prevent, nor is there any medication to treat the disease. Prevention is possible however and it is through preventive strategies that the disease is on the verge of eradication. Prevention strategies include:

  • heightening surveillance to detect every case within 24 hours of worm emergence;
  • preventing transmission from each worm by treatment, cleaning and bandaging regularly the affected skin-area until the worm is completely expelled from the body;
  • preventing drinking water contamination by advising the patient to avoid wading into water;
  • ensuring wider access to improved drinking-water supplies to prevent infection;
  • filtering water from open water bodies before drinking;
  • implementing vector control by using the larvicide temephos;
  • promoting health education and behaviour change.

2018-03-09 05_52_29-Dracunculiasis interventions

 

Country certification

To be declared free of dracunculiasis, a country needs to have reported 0 instances of transmission and maintained active surveillance for at least 3 years afterwards.

After this period, an international certification team visits the country to assess the adequacy of the surveillance system and to review records of investigations regarding rumoured cases and subsequent actions taken.

Key Messages:

Dracunculiasis is a crippling parasitic disease on the verge of eradication, only 25 human cases were reported in 2016.

The disease is usually transmitted when people who have little or no access to improved drinking water sources swallow stagnant water contaminated with parasite-infected water-fleas (Cyclops) that carry infective guinea-worm larvae.

From the time infection occurs, it takes between 10–14 months for the transmission cycle to complete until a mature worm emerges from the body.

Of the 20 countries that were endemic for the disease in the mid-1980s, only 3 countries reported cases in 2016 (Chad (16), South Sudan (6) and Ethiopia (3)).

2018-03-09 05_50_13 Dracunculiasis

In 2017, only two countries reported human cases- Chad and Ethiopia, each with 15 cases. South Sudan and Sudan are currently in the pre-certification stage.

Kenya is the 187th WHO member State to be certified free of Dracunculiasis.

Useful Links:

Link to WHO news release:

http://www.who.int/neglected_diseases/news/Kenya_certified_free_of_guineaworm/en/

Link to WHO’s fact sheet on Dracunculiasis (updated 2017):

http://www.who.int/neglected_diseases/news/Kenya_certified_free_of_guineaworm/en/

Link to WHO page on Dracunculiasis:

http://www.who.int/dracunculiasis/en/

 

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