By Caty Weaver

This is Bill White with the VOA Special English DEVELOPMENT REPORT.

April seventh was World Health Day. The World Health Organization and the International Federation of Red Cross and Red Crescent Societies made blood supply safety the message of the day.

Hospitals and doctors need safe blood to use in operations and other treatments. Safe blood saves lives. Every day, thousands of people would die if other people did not give blood. Most blood is given to four kinds of patients: Pregnant women who suffer bleeding inside their bodies. Children whose blood lacks iron. Accident victims. And people with cancer.

The World Health Organization says a large majority of the world's population does not have a safe blood supply. A WHO study finds that people in poor countries face the most risk from unsafe blood supplies. Many of these countries are also places where diseases are spreading most quickly.

The WHO and the Red Cross and Red Crescent have begun a year-long campaign to improve blood supplies around the world. The groups want to make clear who should give blood and who should not.

The experts say you should only give blood if you are healthy and do not have an infection that can be passed through blood. Most people can give blood as often as every four months. This is important because no blood products can be used after thirty-five days in storage.

Experts say people who do not feel well should not give blood. They say pregnant women or women who have been pregnant within the past year should not give blood either. They also say people with medical conditions like heart disease or diabetes should not give blood. And, people taking some kinds of medicine should not give blood.

The WHO says blood that is given should always be tested for three diseases -- hepatitis B, syphilis and the virus that causes AIDS. The WHO says blood also should be tested for infections like hepatitis C, chagas disease and malaria.

The WHO and Red Cross are urging officials not to pay people to give blood. Studies have shown that blood is more likely to be unsafe when it comes from a person who is paid for the service.

The health organizations say new and safe equipment must always be used to collect blood. This prevents passing an infection to people who give blood.

This VOA Special English DEVELOPMENT REPORT was written by Caty Weaver. This is Bill White.

Voice of America Special English