By Jeannie A. DeVane
Think before you leap into warm fresh water this summer!
Lakes, rivers, hot springs and even soil can contain an ameba, which is a
single celled organism. This organism is called Naegleria fowleri that infects
humans. Naegleria fowleri is considered to be a thermophilic, meaning that it
is warmth loving and occurs in the environment naturally and is worldwide.
Naegleria fowleri
has three stages: The three stages of Naegleria fowleri consists of cysts,
trophozoites, and flagellated forms in its life cycle.
Infection of
Naegleria fowleri: Infection occurs when Naegleria fowleri enters the
body through the nose and travels to the brain destroying brain tissue. The
trophozoite stage is where the nasal mucosa is penetrated and migration to the
brain occurs. Naegleria fowleri can cause a brain infection, and is almost
always fatal. This usually occurs when someone goes swimming or diving, water
gets sucked up the nose giving the ameba an advantage to make its way to the
brain. Drinking contaminated water cannot lead to this infection and the
infection does not spread through person to person contact. These infections
are rare, but they do happen and as the environment warms up, lakes and rivers
tend to warm causing this to be a problem due to the hot temperature air and
low water levels.
Symptoms of
Naegleria fowleri: Naegleria fowleri infection causes a fatal acute
central nervous system disease known as PAM (primary amebic
meningoencephalitis). PAM results in inflammation of the brain, inflammation of
the lining of the brain, and inflammation of the spinal cord leading to
destruction of brain tissue in the human body. Symptoms of Naegleria fowleri:
Initial symptoms start one to seven days after infection including fever,
headache, stiff neck, and nausea and vomiting. Later symptoms include loss of
appetite, lack of attention to people and surroundings, loss of balance and
bodily control, hallucinations, seizures, and coma. Death can result within 1
to 12 days and depends on the rate of the infection.
Treatment of
Naegleria fowleri: The treatment of Naegleria fowleri is still unclear
for this infection. Laboratory drugs have been used to attempt to treat
Naegleria fowleri, but their effectiveness is unknown due to the fact almost
all infections tend to be fatal against Naegleria fowleri even when the patient
is being treated.
Diagnosis of
Naegleria fowleri: Naegleria fowleri is diagnosed through the use of
identifying the organisms, nucleic acid, and antigens in CSF, biopsy, and
tissue specimens. Cysts are not seen in brain tissue.
Naegleria fowleri
infection prevention: Avoid diving or jumping into freshwater when
water temperatures are hot and the water levels are low. When diving or jumping
into freshwater hold your nose closed. Use a nose plug or clip to prevent water
from being forced up into the nasal passages. While you are swimming try to
hold your head up above the water. Try not to dig or stir up the sediment while
swimming in shallow freshwater.
References
1. Virginia Department of Health (VDH). Naegleria fowleri.
Updated 08/18/2011 http://www.vdh.state.va.us/epidemiology/DEE/factsheets/pdf/Naegleria%20fowleri%20fact%20sheet.pdf
2. Centers for Disease Control and Prevention (CDC). http://www.cdc.gov/parasites/naegleria/biology.html
3. Shakoor S, Beg MA, Mahmood SF, Bandea R, Sriram R, Noman
F, Ali F, Visvesvara GS, Zafar A. Primary amebic meningoencephalitis caused by Naegleria
fowleri, Karachi, Pakistan. Emerg Infect Dis. 2011 Feb;17(2):258-61.
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