By the BBC's Jill McGivering

Officials from the World Health Organization say they are concerned about a possible rise in tuberculosis cases in Afghanistan.

And they also warn of the possible emergence of drug-resistant strains as a result of the present unrest.

In some areas, the snow and ice already building up on the ground will not thaw until next March

The news comes as officials from the World Food Programme are preparing emergency teams to cope with heavy snows which will block vital aid routes in many parts of the country.

Tuberculosis was already a major concern for Afghanistan.

The World Health Organization (WHO) says there are 60-70,000 new cases every year, and about 70% of those patients are women.

Incomplete courses

The current security and transport problems now mean drugs may be failing to reach people who need them.

Patients who have already started medication may be unable to complete the course.

Afghans will be dependent on aid for some time

WHO officials say this is also sparking concerns about the possible emergence of drug-resistant strains.

They also warn the extra psychological stress and physical hardship caused by the conflict could mean that dormant cases of the disease recur.

The warnings come as World Food Programme officials are trying to put in place food stocks to support one million people in Afghanistan's central highlands.

They are in the most acute danger of being cut off from aid supplies as snowfall intensifies.

Officials say a team of 24 Swedish rescue workers are heading for the worst affected areas to set up base camps and work on keeping roads clear.

An avalanche control unit is also being set up, which plans to pre-empt avalanches by triggering them where necessary.

In some areas, the snow and ice already building up on the ground will not thaw until next March, compounding the problems faced by aid agencies as they try to get vital supplies to those who need them.