The Study

The city of Karachi, Pakistan has seen large numbers of Naegleria fowleri deaths in recent years, particularly in people with no history of aquatic recreational activities like swimming, etc.

Image/Robert Herriman
Image/Robert Herriman

A new study published in International Journal of Infectious Diseases (IJID) points to the source of the amoebic parasite as the Karachi water supply.

Twenty four confirmed cases were reported from Karachi in last 3 years (2015-2017).

Researchers collected water samples from different locations of Karachi city which include two reservoirs and catchment areas supplied by these distribution systems. Water samples were tested for presence of N.fowleri using culture and real time PCR amplification method. Data was collected for all cases reported positive for N.fowleri infection using real time PCR.

They reported the presence of N. fowleri in domestic water supply in Karachi city.

The fact that the victims had no history of swimming and other fresh water recreational activities and the presence of the parasite in the water system, researchers conclude exposure was during bathing or ritual nasal cleansing from domestic water supply.

They say– Detection of N. fowleri in domestic water systems in Karachi is alarming and poses a significant risk of deadly future outbreaks. The health authorities should respond to the situation on an urgent basis.

What is Naegleria fowleri?

Naegleria fowleri Life Cycle/CDC
Naegleria fowleri Life Cycle/CDC

Naegleria fowleri (commonly referred to as the “brain-eating amoeba”), is a microscopic amoeba which is a single-celled living organism. It can cause a rare and devastating infection of the brain called primary amebic meningoencephalitis (PAM). The amoeba is commonly found in warm freshwater such as lakes, rivers, ponds and canals.

Infections can happen when contaminated water enters the body through the nose. Once the amoeba enters the nose, it travels to the brain where it causes PAM (which destroys brain tissue) and is usually fatal. Infections usually occur when it is hot for prolonged periods of time, which results in higher water temperatures and lower water levels.

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Naegleria fowleri infections are rare. Most  infections occur from exposure to contaminated recreational water. Cases due to the use of neti pots and the practice of ablution have been documented.

The practice of ablution is included in Yogic, Ayurvedic, and Islamic traditions. Within the Islamic faith, ritual nasal rinsing is included in a cleansing process called “wudu” or “ablution.” It is usually performed several times a day in preparation for prayer, according to the Centers for Disease Control and Prevention.

You cannot be infected with Naegleria fowleri by drinking contaminated water and the amoeba is not found in salt water.

Initial symptoms of PAM usually start within 1 to 7 days after infection. The initial symptoms may include headache, fever, nausea, or vomiting. Other symptoms can include stiff neck, confusion, loss of balance, seizures, and hallucinations. After the start of symptoms, the disease progresses rapidly.