L & R: Trophozoites of N. fowleri in brain tissue, stained with H&E. Center: Ameboflagellate trophozoite of N. fowleri. Credit: DPDx
Naegleria fowleri, commonly called the `brain eating amoeba’, has been blamed for 10 deaths in Karachi, Pakistan over the summer according to a Pakistani official with the World Health Organization.
The AP is reporting this morning that Musa Khan, the head of Pakistan’s DEWS (Disease Early Warning System), announced that the deaths occurred between March and September.
While it is exceedingly rare, we hear of a few fatal cases of PAM (Primary Amoebic Meningoencephalitis) each year caused by this water-borne organism.
It is usually acquired while swimming in warm lakes and streams, but last year we saw a couple of cases in Louisiana related to the use of Neti Pots for nasal irrigation (see FDA Advice On Safe Use Of Neti Pots).
Photo Credit FDA
Nasal irrigation is practiced daily by many in the Muslim community, and is suspected to be the route by which these Pakistani infections were acquired.
Several years ago nasal irrigation with N. fowleri contaminated tap water in Karachi, Pakistan was suspected to have caused 13 cases over 18 months. The CDC’s EID journal carried a dispatch on this outbreak in 2011:
Sadia Shakoor, Mohammad Asim Beg, Syed Faisal Mahmood , Rebecca Bandea, Rama Sriram, Fatima Noman, Farheen Ali, Govinda S. Visvesvara, and Afia Zafar
We report 13 cases of Naegleria fowleri primary amebic meningoencephalitis in persons in Karachi, Pakistan, who had no history of aquatic activities. Infection likely occurred through ablution with tap water. An increase in primary amebic meningoencephalitis cases may be attributed to rising temperatures, reduced levels of chlorine in potable water, or deteriorating water distribution systems.
This latest outbreak has inspired heated debate over the water quality in Pakistan’s largest city (pop 13 million). This report from today’s Express Tribune:
By Saad Hasan / Samia Malik
Published: October 9, 2012
As more cases of the deadly illness caused by the amoeba Naegleria fowleri continue to surface, officials have started wrangling with one another over the quality of water that runs through the city’s pipelines.
The managing director of KWSB, Misbahuddin Fareed, said on Monday that the results showed that the level of chlorine was indeed low – it was 0.15 (parts per million) ppm when it should have been at least 0.5 ppm.
Despite this, the manager refused to believe that the water was contaminated and asked Aga Khan University to conduct research to determine whether the water did indeed carry the organism. “Our water is running water anyway. It does not stagnate and allow germs to multiply.” He said that the organisation checks the quantity of water every three hours.
Since millions of people swim in waters where this amoeba naturally occur (or are otherwise exposed) and only a small handful of infections result, the odds of acquiring this infection are extraordinarily low.
Still, as this infection is almost always fatal, that makes the advice of using distilled, sterile or previously boiled water in your neti pot a reasonable enough precaution.
Photo Credit – Florida DOH