The need for effective disinfection of anthrax spores was highlighted in the ASM Biodefense Research Meeting, held recently. It has now been found that anthrax spores may develop resistance against the currently adopted disinfection methods due to their improved ability to attach and adapt to the interior of water pipes.
The researchers have therefore pointed out to the need for alternate disinfection methods related to water treatment, in the unlikely event of the release of anthrax in the water supply.
The researchers analyzed the survival ability of the anthrax spores in chlorinated water (a chlorine concentration of 1mg/l). This is the chlorine content available in tap water that is supplied to households. No significant reduction in the spore form could be observed after 60 minutes.
It has been further stated that non-sporocytic forms of waterborne pathogens (99.99%) would be killed in just one minute if exposed to the same chlorine concentration. The effect would be more prominent at higher chlorine concentrations.
In addition, it was found that after 6 hours, 20-40% of anthrax spores had successfully attached themselves to the interior of pipes, when the contaminated water was made to flow through a continuous loop (copper, CPVC or galvanized iron) with serial sections. A 95% attachment was found when iron was used as the pipe construction material. An enhanced attachment was used when biofilms were present inside copper pipes.
'The data seem to suggest that anthrax spores can tolerate water treatment, can attach to pipes or biofilms within the pipes, and could pass through pipe systems to reach the consumer tap. In the unlikely event of the release of anthrax spores into the water supply, alternate decontamination protocols (such as exposure to higher concentrations of chlorine or an alternate disinfectant for an extended period of time) may be needed as regular treatment methods may not be effective,' concluded the researchers.