This is an extremely low infectious dose (only 1-10 organisms required), making C. burnetii one of the most infectious organism known to man.

This vastly exceeds the infectious dose of 1000-10,000 bacteria for humans.

Each has slightly different biological properties, including shape, incubation time, infectious dose, target tissue and clinical signs of disease.

Plaque-based assays are the standard method used to determine virus concentration in terms of infectious dose.

No one knows what an infectious dose of listeria is, Dr. Wachsmuth said.

We will never be able to define a single infectious dose for everyone.

The infectious dose is 1000-10,000 bacteria (although ten to five hundred bacteria can be enough to infect humans).

The researchers do not know what the infectious dose is, or enough about hypervirulent strains.

A high infectious dose is required; the carrier state persists for several days.

Typically animals are exposed to 10-100 times the infectious dose at which 50% of the animals become infected (ID50).