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Question from Gino to Jane:

I recall, (but would be grateful if you could confirm or correct me on this) that confirming the positive presence of Cholera (as opposed to some other type of faecal coliform) is quite a complicated test and requires some fairly sophisticated laboratory equipment.

Jane: can you tell me more about what tests need to be done to confirm the presence of Cholera? Assuming that this is what Paul wants. Are there any kits that can be used in the field to test for Cholera? Are you familiar with “Coli alert” and “Colitest” mentioned in Paul’s e-mail below?

I am not sure how familiar you are with the Del Agua kit but I understand that, at least the older (basic) single incubator model “checks for” the presence of thermotolerant (faecal) coliforms by “growing” these coliforms (at 44 deg C). The particular coliforms grown during the use of this equipment were selected (because of their hardy nature) really as an indicator of the possible presence of other possibly more harmful faecal organisms.

Although I believe that the Del Agua kit is not capable of giving a positive confirmation of Cholera (as opposed to some other gastroenteritis disease), the kit is a valuable tool in checking water samples for the presence of other faecal coliforms which can indicate the possible presence of the Cholera causing bacteria.

I have no personal knowledge or experience of Haiti, but I would suggest that in any situation where sanitation is poor or non-existent and where people are living densely packed together, appropriate precautions to reduce the chances of a Cholera outbreak occurring should be taken as soon as possible. Measures could include chlorinating the water supply to disinfect it. At the risk of stating the obvious, don’t wait for the presence of Cholera to be confirmed, chlorinate the water supplies as soon as possible.

Answer from Jane: Good to hear from you, and I agree totally that the most important issue is to look for coliforms as a marker of faecal contamination rather than spending time and resources on searching out cholera in the environment. The ecology of cholera is complex and I believe detection in the environment is difficult. Easier would be detecting it in fresh stool of symptomatic people (i.e. those with profuse diarrhoea) - you can see the little buggers whizzing around under the microscope. The other issue is that there is a range of pathogens that can cause severe cholera-like watery diarrhoea and it seems to me that detecting cholera or not detecting it is of little value in relief conditions... although I have a vague recollection that funding/resources might be more forthcoming in a cholera outbreak??? (You'd know more about this than me, Gino).

Regards

Gino Henry and Jane Wilson-Howarth