Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 22, Number 10—October 2016

Naegleria fowleri Meningoencephalitis Associated with Public Water Supply, Pakistan, 2014

Najia K. Ghanchi, Erum Khan, Azam Khan, Wali Muhammad, Faisal Riaz Malik, and Afia ZafarComments to Author 
Author affiliations: Aga Khan University, Karachi, Pakistan (N.K. Ghanchi, E. Khan, F.R. Malik, A. Zafar); Karachi Water and Sewerage Board, Karachi (A. Khan); World Health Organization, Karachi (W. Muhammad)

Main Article


Characteristics of 13 water samples collected from water treatment plant A and its distribution system, including water supplied to the apartment and neighborhood mosque of a patient with primary amebic meningitis, Karachi, Pakistan, 2014*

Water supply Sample location Sample type Total chlorine, mg/L Temperature, °C† Culture positivity for FLAs PCR results for Naegleria fowleri amebae‡ Distance relationships of water samples
Reservoir§ Water from Kinjhar Untreated ND 30 ++ From reservoir to plant A, ≈100 km
Water treatment plant A
Filtration unit¶ Treatment underway <0.5 29.5 ++
Plant A exit point
Filtered and chlorinated

Pumping station#
Pumping station, site 1 Filtered and chlorinated ND 30 ++ From plant A to pumping station, ≈11 km
Pumping station, site 2
Filtered and chlorinated

Catchment areas:
patient’s apartment and neighborhood Mainline Filtered and chlorinated ND 30 From pumping station to patient’s house, 1km
Underground boring well water** Untreated ND 28.5 + Within patient’s house, ≈10 m
Underground tank Mixed†† ND 28 + Within patient’s house, ≈10 m
Overhead tank Mixed ND 31 ++ + Within patient’s house, ≈10 m
In-house storage tank‡‡ Mixed ND 30 ++ Within patient’s house, ≈5 m
Bathroom Mixed ND 29 + Within patient’s house, ≈5 m
Neighborhood mosque Filtered and chlorinated ND 31 ++ + From patient’s house to mosque, ≈100 m

*FLAs, free-living amebae; ND, not detected; ++, >3 amebae seen with 40x magnification; +, 1–3 amebae seen with 40 x magnification; –, no amebae detected.
†Water temperatures of 25°C–40°C are conductive for flourishing of Naegleria fowleri amebae.
‡PCR was negative for other pathogenic FLAs such as Balamuthia or Acanthamoeba spp.
§Kinjhar Lake, located in Sindh province, Pakistan, is the main reservoir that supplies water to Karachi.
¶The filtration unit was the only site for which 2 samples were taken; only 1 sample was taken from all other specific sample locations.
#Samples were taken from a single pumping station at 2 separate sites.
**Underground wells provide additional water supplies locally known as boring wells.
††Water from these wells is not treated and is mixed with treated water from the main water supply in storage tanks.
‡‡Underground and overhead tanks are shared by >100 households, so for continuous water supply, residents keep small tanks in their homes.

Main Article

Page created: September 19, 2016
Page updated: September 19, 2016
Page reviewed: September 19, 2016
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.