Outbreak of ‘Brain-eating Amoeba’ in Karachi
What is Naegleria?
Naegleria is an amoeba (single-celled living organism) commonly found in warm freshwater (for example, lakes, rivers, and hot springs) and soil. Only one species (type) of Naegleria infects people: Naegleria fowleri.
How does infection with Naegleria fowleri occur?
Naegleria fowleri infects people when water containing the amoeba enters the body through the nose. This typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. The Naegleria fowleri amoeba then travels up the nose to the brain where it destroys the brain tissue. You cannot be infected with Naegleria fowleri by drinking contaminated water.
Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water and contaminated tap water) enters the nose, for example when people submerge their heads or cleanse during religious practices (wuzu), and when people irrigate their sinuses (nose) using contaminated tap water.
In what water temperature does Naegleria fowleri cause infection?
Naegleria fowleri is a heat-loving (thermophilic) microbe. It grows best at higher temperatures up to 115°F (46°C) and can survive for short periods at higher temperatures.
Can I get a Naegleria fowleri infection from a disinfected swimming pool?
No. You cannot get a Naegleria fowleri infection from a properly cleaned, maintained, and disinfected swimming pool.
When do Naegleria fowleri infections most commonly occur?
While infections with Naegleria fowleri are very rare, they occur mainly during the summer months of July, August, and September.
Can infection be spread from one person to another?
No. Naegleria fowleri infection cannot be spread from one person to another.
What are the symptoms of Naegleria fowleri infection?
Naegleria fowleri causes the disease primary amebic meningoencephalitis (PAM), a brain infection that leads to the destruction of brain tissue. In its early stages, symptoms of PAM may be similar to symptoms of bacterial meningitis.
Initial symptoms of PAM start about 5 days (range 1 to 7 days) after infection. The initial symptoms may include headache, fever, nausea, or vomiting. Later symptoms can include stiff neck, confusion, lack of attention to people and surroundings, loss of balance, seizures, and hallucinations. After the start of symptoms, the disease progresses rapidly and usually causes death within about 5 days (range 1 to 12 days).
What is the actual mechanism of death from Naegleria fowleri infection?
The infection destroys brain tissue causing brain swelling and death.
What is the fatality rate for an infected person who begins to show signs and symptoms?
The fatality rate is over 99%.
Is there effective treatment for infection with Naegleria fowleri?
It is not clear. Several drugs are effective against Naegleria fowleri in the laboratory. However, their effectiveness is unclear since almost all infections have been fatal, even when people were treated with similar drug combinations.
What should I do if I have been swimming or playing in freshwater and now think I have symptoms associated with Naegleria fowleri?
People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck, and vomiting, particularly if they have been in warm freshwater recently.
What swimming behaviors have been associated with Naegleria fowleri infection?
Behaviors associated with the infection include diving or jumping into the water, submerging the head under water or engaging in other water-related activities that cause water to go up the nose.
How can I reduce the risk of infection with Naegleria fowleri?
- Use chlorinated and boiled water.
- Hold your nose shut, use nose clips, or keep your head above water when taking part in water-related activities in bodies of warm freshwater.
- Avoid water-related activities in warm freshwater during periods of high water temperature and low water levels.
- Avoid swimming in waters where you suspect poor hygiene and insufficient chlorination.
If you are irrigating, flushing, or rinsing your sinuses (for example, Wuzu), use water that has been:
- previously boiled for 1 minute and left to cool or
- filtered, using a filter with an absolute pore size of 1 micron or smaller or
- purchased with a label specifying that it contains distilled or sterile water.
Dr. Kamran Dawood
Consultant Microbiologist and
Head of Microbiology and Infection Control Department
Further Reference: http://www.cdc.gov/parasites/naegleria/general.html
Medical Disclaimer: This is general information provided for educational and awareness purposes. This information is not intended or implied to be a substitute for professional medical advice, diagnosis, or treatment.
- Brain Eating Amoeba invades Pakistan | Teeth Maestro (Teeth.com.pk)
- Brain-eating amoeba kills at least 10 in Karachi (guardian.co.uk)
- Fatal parasite strikes in Karachi (bbc.co.uk)
- What is the “brain-eating” amoeba found in Pakistan? (cbsnews.com)
- Pakistan: No risk of Naegleria if water boiled or chlorinated, say experts (crofsblogs.typepad.com)
- Naegleria Fowleri: ‘Brain-Eating Amoeba’ Kills 10 In Pakistan (huffingtonpost.com)
- Deadly Amoeba in Tap Water (foxnews.com)