The population suffered from periodic epidemics, including several serious outbreaks of black death.

Whilst treating patients during one of the periodic epidemics of cholera there, he himself contracted the disease and died on 24 November 1850.

With its introduction in populated areas in India, China and Europe, smallpox affected mainly children, with periodic epidemics that killed up to 30% of those infected.

What it looked like, and was, was periodic, worldwide epidemics of insanity.

It also will continue to cause periodic epidemics in areas such as South America with higher, but still inadequate, vaccination rates.

The high birthrate was offset by a very high rate of infant mortality, plus periodic epidemics and harvest failures.

Surveillance data show a clear pattern of strong seasonal epidemics in temperate regions and less periodic epidemics in the tropics.

The population suffered from periodic epidemics, including several serious outbreaks of bubonic plague.

The situation was further exacerbated by the increased death rate during periodic epidemics such as cholera, occurring unchecked within these overcrowded urban environments.

Historically, damp northern countries that have depended on rye as a staple crop were subject to periodic epidemics of this condition.