1. Dorsch MM, Cameron AS, Robinson B: (1983) The epidemiology and control of primary amoebic Meningoencephalitis with particular reference to South Australia . Trans Soc Trop Med Hyg, 77,.3, 372-377 :
2. Robinson, B S (1977), Effectiveness of chlorine in the control of Naegleria: laboratory and field studies in South Australia . Proc. 7th. Federal Convention Australian Water and Wastewater Association, Canberra 1977 pp 465-478.
The map insert outlines the additional confirmed cases of Naegleria Meningo-encephalitis in Australia between 1955 and 1981. There were no further cases in the Spencer Gulf area after 1972 presumably due to attention to chlorination of the water pipe line but also and mainly due to chlorine in the local supply..
Ten years later (1980 –1982) several additional cases were reported. Whyalla in 1981. Other reports arrived from towns in NSW, Queensland and WA.: (Richmond NSW.1981,Merredin WA. 1982, Beverley and York WA. 1980,.and Charters Towers QLD 1982)..The sporadic nature was suggestive of local rather than general factors. These are summarised in the table below from Ref:1. There was one additional case in 1995 when an American couple camped at Branch Creek and swam in the billabong. The husband died in Darwin . (personal reference Bret Robinson)
The conclusions reached by the authors of the above publications seem to indicate that while there are some doubts about the effectiveness of chlorination by some researchers, it appears that chlorine concentrations of 0.5mgms per litre of local water supply make the risk of PAME infection negligible.(Ref. 1)
The length of the pipeline and the difficulty of maintaining effective concentrations over long distances was noted during the Spencer Gulf outbreak and additional chlorination stations were added to the pipe line. A more stable form of chlorine in the form mono-chloramine NH2Cl also improved the degree of disinfection. Attention to local chlorination was vital.
The authors also suggested that air transmission by air-borne dust is unlikely as cysts of Nagleria fowleri will be desiccated within five minutes
The authors briefly refer to the relative ineffectiveness of antibiotics such as Amphotrricin B, Miconazole, Rifampicin and others. There has been little change but combinations such as Floconozole, Amphotericin B, Rifampicin and Azithrumacin have been recently reported to be of some use. (source: pubmed)
The scattered and diffuse incidence of the disease in Australia during 1980-1982 is difficult to explain. The disease occurs almost invariably in the summer months, but while Merredin and Beverley (WA) lie on the Kalgoorlie pipeline the NSW. and Qld. cases were associated mainly with local swimming pools. It may be possible that as in the Czech Republic the source could have been in an isolated side pool which escaped general chlorination. .Dr. Robinson suggested another possibility. The diffuse incidence may be related to the generally low densities of the amoebae in water with insufficient dose of inoculum required for infection. However in some areas, due to lack of chlorination or other factors such as temperature, soil contamination and stagnation. the inoculum will be large enough to be infective.
A French group studied the incidence and numbers of amoebae associated with nuclear reactor cooling systems. It has developed a risk analysis model which predicts the likely incidence of PAME as a function of the degree of contamination. Based on their animal work the French Health Authorities have set a maximum level of 100 N. fowleri per litre not to be exceeded in watercourses where human exposure is possible.
Applied and Experimental Microbiology, July 2001, p.2927-2031.