Biology‎ > ‎


posted May 29, 2016, 1:19 PM by Upali Salpadoru   [ updated Nov 5, 2017, 11:04 PM ]

Drinking water from the Holy Rivers like  Ganges & Yamuna,

could cure cholera”, Fact or fiction?

Phage -2.jpg

Fig.1. Phages landing on a bacterium.


Ernest Hankin (UK), in 1896 found that cholera bacteria that thrived in tap water had no success in Ganges water.

He found that even the filtered river water could destroy Vibrio cholerae bacteria, unless he boiled it.

The agent that killed bacteria was only discovered in 1916 by Felix d'Herelle (Can) from Pasteur Institute in Paris. These have been named as Bacteriophages as they destroy bacteria. They cannot even be classified as living things. They are described as ,’ Nano particles capable of self replicating”.

Fig.2 Three phages have landed on the surface of a Bacterium.

A baceriophage is very much smaller than a bacteria.  They are really viruses. Cousins of those that cause, flu, pox and ebola.No reason to worry; phages do not attack human cells.

The longest war in recorded history may be 100 yr war, but  there is a war that had been raging for millions of years.  The war between the phages and bacteria. It has been estimated that phages slaughter half the total number of bacteria in 2 days.

Then the question arises, “Why won’t the bacteria become extinct?.

There are two reasons for this.

  1. They propagate very fast.( So are the phages)

  2. They develop various defensive mechanisms against the evolving tactics of the phages.

While the war rages What shall we do ?

Fig.3 A phage attacking a bacteria.

The obvious thing we have to do is to take the side of the Phages. They do no harm to us unlike some bacteria who are infectious.

Phage Therapy

Phage therapy started before the discovery of antibiotics. The difficulty with phages is that they are highly specific.One kind of a phage can generally destroy only one type of bacteria. But now when some bacteria develop resistance even to the strongest antibiotics, the doctors are inclined to go back to phage therapy. Phages can change their mode of attack when the enemy changes unlike the antibiotics.