Initially, 136 people in the southern Rostov region were reported to have fallen ill with suspected Congo-Crimean Haemorrhagic Fever.

Then, within days, a smaller number of cases were reported in the neighbouring Volgograd and Stavropol regions, with three deaths.

But Gennady Vyakhirev, head of the civil defence unit handling the outbreak say that most are now out of danger.

Ticks responsible for infection

The disease is thought to be spread by tick-bites, or possibly through close contact with infected people.

Its symptoms are similar to those suffered by those infected by the deadly Ebola and Marburg viruses, and up to half of those infected have died in previous outbreaks in Russian, the Middle East and Africa.

The onset of illness is rapid, beginning with cold and flu-like symptoms, and continuing with internal bleeding from internal organs, including the brain.

In some cases, the patient can bleed to death through the nose, eyes, mouth or even womb.

Reports of a "mystery illness" in the Russian media caused widespread panic in the region, with many villagers leaving their homes.

Some reports suggested one village was being "punished by God", or that Chechens had poisoned the water supply.

Other rumours suggested that garlic and vodka prevented infection, causing shortages in the region.

'Peak has been reached'

The federal health ministry set up a special emergency commission, sending specialists from Moscow, 600 miles to the north, but experts deny the infection has become an epidemic.

Mr Vyakhirev said: "We can say the peak seems to have already been reached. It is under control."

The quick spread of the disease is being blamed on the unseasonably hot weather in Russia.

The period between infection and the arrival of symptoms is around 12 days, allowing doctors to work out accurately whether an outbreak is subsiding or increasing.

There is no cure for the virus, and the only treatment is one to boost the patient's immune system.

However, this particular fever is not as deadly as Ebola, which, depending on its strain, kills between 50 and 90% of those infected.

In England and Wales, there were 32 reported cases of viral haemorrhagic fever between 1991 and 1998, including 10 in 1996.

While Marburg and Ebola are among the most deadly viruses, their ability to immobilise the victim within a few days is considered an advantage in preventing collossal epidemics.

Although the viruses can be spread easily, the swift onset of devastating symptoms limits the likelihood of the victim travelling, coming into contact with, and infecting many more people.

The Crimea haemorrhagic virus, while slower to develop, seems less contagious.