These algae may produce protective toxins which can kill fish in the water.
Sometimes the germs produce chemicals or toxins which causes the disease.
Normally, even if babies have these bacteria, they don't produce toxins and remain healthy.
Some plants only produce toxins in small amounts, and rapidly deploy them to the area under attack.
It produces enough toxin to kill the entire city.
Cyanobacteria can also produce chemical toxins that have been a problem in drinking water.
The bacteria multiply in foods and produce toxins especially if food is kept at room temperature.
Even more dangerous: some planktons produce toxins, and those species are spreading.
Under certain conditions, some species of marine algae form blooms with can produce natural toxins.
When the same microbe grows in blood, it can produce toxins that cause shock and death.