NAEGLERIA: PREVENTABLE BY WATER CHLORINATION

Abstract

Naegleria fowleri is a free-living, thermophilic protist belonging to phylum Percolozoa, typically found in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. It is also found in soil, near warm-water discharges of industrial plants, and in poorly chlorinated, or unchlorinated swimming pools. The trophozoite or ameboid form encysts under unfavorable circumstances and converts to a temporary biflagellate form if exposed to high temperatures. The flagellate form can exist in the cerebrospinal fluid where it can be detected microscopically and cultured on non-nutrient agar over a lawn of Escherichia coli. In their free living state, trophozoites feed on bacteria, while in the tissues, they phagocytize red and white blood cells and damage the tissues. N. fowleri also known as the brain eating amoeba can invade and attack the human brain, causing primary amoebic meningoencephalitis (PAM). Although this occurs rarely, such an infection nearly always results in the death of the victim. The case fatality rate is greater than 95%.
In Pakistan the first case surfaced in Karachi in 2008 and since then death toll due to PAM is on the rise. From July to October 2012, 44 people died within a week in the Sindh province from Naegleria infection. At least 13 cases have been reported in Karachi, Pakistan, in patients who had no history of aquatic activities.10 In 2014, 12 victims succumbed to this infection in Pakistan. Infection likely occurred through ablution performed with poorly chlorinated water containing Naegleria.
Sindh provincial health authorities along with many civic agencies collected and tested 549 samples of water from various parts of the city and found no chlorine in 228 samples which make 41.5% of the total. A significant number of the remaining samples had less than the desired levels of chlorine. This is an alarming situation. In a megacity like Karachi with a population of more than 20 million where most people live in congested places, the non-availability of chlorinated water increases the risk of Naegleria infection.
The incidence of infection itself is likely to increase as temperature range is rising through climate change. Also, the number of reported cases are expected to show an increase, simply because of better informed diagnoses being made both in living patients and also in autopsy findings.
The first case of the current year occurred in April in an 18 year girl who died of PAM within a day after being admitted to a private hospital in critical condition. So far, up to 31 May 2015, seven deaths have occurred due to Naegleria infection which is likely to increase if appropriate measures are not taken. We strongly recommend that provincial governments should adopt a strategy for proper chlorination of water not only in Karachi but the whole country. The government should also invite NGOs and other civic agencies to accomplish this pushed-behind-the-back mountainous task. At personal level at least boiled water should be used for nasal irrigation during ablution.