PAM after playing all day on a slip-n-slide,
and N. fowleri were detected in the residential plumbing system, hot water heater,
and hoses supplying the slip-n-slide. At
this time, the presence of N. fowleri was
also confirmed in the public drinking
During the 1970s and 1980s, a number
of cases of PAM were reported in Australia
and N. fowleri was detected in public water
supplies (Dorsch et al. 1983). Since that
time, several water systems in the states
of Western Australia and South Australia
continue to monitor regularly for N. fowleri
colonization in drinking water distribution systems. Australian Drinking Water
Guidelines indicate that adequate residual levels of chlorine and monochloramine concentrations (0.5 mg/L or higher)
throughout the water supply system at
all times can control N. fowleri (Australian
Drinking Water Guidelines, 2011).
Maintenance of cooler temperatures in
the distribution system can also be one of
several effective management strategies
for N. fowleri. According to the “Amoeba
Response Protocol” in Western Australia,
the water should be monitored for amoebae if the water temperature within the
distribution system exceeds 20°C (68°F).
In November 2013, the Louisiana
Department of Health and Hospitals
(LDHH) put in place an Emergency Rule
addressing N. fowleri. This rule requires
all water systems in Louisiana to increase
monitoring of distribution systems by 25%
Rule, the Surface Water Treatment Rule,
and the Disinfectants/Disinfection
By-Product Rule, and to increase disinfec-
tant levels to 0.5 mg/l free or total chlorine.
The requirements of this rule became effec-
tive on February 1, 2014 (Louisiana 2013b).
A monitoring program of Louisiana public
water supplies that began in August 2014
has found N. fowleri in the distribution sys-
tems of two water supplies where disin-
fectant residuals were very low (Louisiana
Center for Environmental Health n.d.).
There are several sampling methods.
Simple grab sampling (~ 1 L) or large
volume sampling methods (where hundreds of liters of sample are concentrated
using ultrafiltration) have been used to
detect N. fowleri. Swab sampling has also
been used to detect amoebae in premise
plumbing systems. Appropriate handling
Source: CDC 2014.
Figure 2. Reported PAM cases (n=132) caused by N. fowleri from 1962 to 2013