Koorabye (Western Australia) – Naegleria fowleri detection

Naegleria Species:

9 tests above ADWG Guideline 2012-2014

2 tests above ADWG Guideline 2018-2020

Eighty per cent of communities sometimes failed drinking water tests for Naegleria or E. coli
Over the two years to June 2014, at least one community failed a water quality test every month for either E. coli or Naegleria (Figure 4). In January 2014, twelve communities failed one or both tests. Sixty-eight communities had at least one test failure over the two years.
Data is not available to show how many people fell ill as a result of these failures because the small number of individuals affected does not show up in health statistics, but the risks are significant at a community level and well understood by stakeholders. By comparison, Health has reported no failures for E. coli or Naegleria at any test site in WA managed by Water Corporation since at least 2008.

Over the two years to June 2014, thirty-nine communities had two or more failures, while 29 had three or more. In that period, Koorabye has failed 11 times, making tap water unsafe for much of that time. However, we note that the Program installed a chlorination unit at Koorabye in July 2014, making the water much safer to drink since then. We also note that no Pilbara communities failed E.coli tests in the 12 months to April 2015.
The four communities with the worst microbiological performance were among 33 that still had UV water treatment systems at June 2014. These systems are ineffective if the power fails or the water is not clear. Housing is replacing UV systems with more effective chlorination systems as funds become available.

Western Australian Auditor General’s Report Delivering Essential Services to Remote Aboriginal Communities  May 2015

“GUIDELINE No guideline value is set for Naegleria fowleri in drinking water, but an ‘action level’ is recommended for water supplies likely to be contaminated. If the organism is detected, advice should be sought from the relevant health authority.

Naegleria fowleri is a free-living, thermophilic amoeboflagellate which causes the waterborne disease primary amoebic meningoencephalitis (PAM). This rare but fatal condition has followed use of water for swimming, or domestic bathing. The organism occurs naturally in freshwater of suitable temperature, feeding on bacteria. Its occurrence is only indirectly related to human activity, inasmuch as such activity may modify temperatures or promote bacterial production. PAM has been reported from many countries, usually associated with thermally polluted environments, geothermal water or heated swimming pools. N. fowleri is almost exclusively aquatic, and water is the only known source of infection. Numerous nonvirulent Naegleria species are known in Australia.

PAM cases have been recorded from South Australia, Western Australia, Queensland and New South Wales; Naegleria fowleri has been detected in water in each of these states and in the Northern Territory. Australia is the only country where N. fowleri has been detected in public water supplies (Dorsch et al. 1983). Most of the available data on the density of N. fowleri in water relates to water supplies in South Australia (including the highest reported densities). In temperate Australia, significant seasonal cycles of density occur, from below one organism per litre to hundreds or thousands per litre in poorly disinfected water (Robinson and Christy 1984). N. fowleri detected at water temperatures below 18°C is likely to be present as cysts, which are not infectious, but which may seed a suitable environment.” Australian Drinking Water Guidelines 2011.

E.coli:

10 tests above ADWG Guideline 2012-2014

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG