Plague still exists in many parts of the world, with most human cases reported in Africa nowadays.
The disease provokes flu syndrome in most human cases, but also severe encephalitic or haemorrhagic forms and death.
Although most human cases are sporadic, familial cases (<10%) with autosomal dominant genetic components are not uncommon in clinical practice.
European Union health officials emphasize that most human cases of the flu have been mild and that patients have recovered without special treatment.
"Plague epidemics have occurred in Africa, Asia and South America, but most human cases since the 1990s have occurred in Africa," it said.
So far, most human cases have occurred in rural or semirural areas where many households keep small free-roaming poultry flocks that sometimes enter homes.
William Gerrish, a spokesman for the department, said that in the past most human cases were reported in the first week of September.
In the neighborhoods of northern Queens that had the most human cases last year, many people shopping and strolling this week said they were already worried about the West Nile virus.
Today most human cases are sporadic, occurring in rural areas by infection from wild rodents such as ground squirrels, but in the past huge numbers of persons were infected by fleas from rodents.
In Latin America, most human cases are caused by vampire bats.
In these countries, backyard poultry owners and their families, from where most human cases have been reported, use no protection whatsoever.
