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Chapter 2 of 16

Six diseases cause 90% of infectious disease deaths

• A handful of diseases have plagued mankind though the ages.
• Today, they have been joined by AIDS/HIV and cause half of all premature deaths

Graphs:

• Leading infectious killers,
• The death of a child

Initiative : Combating childhood deaths

No more than six deadly infectious diseases - pneumonia, tuberculosis, diarrhoeal diseases, malaria, measles and more recently HIV/AIDS - account for half of all premature deaths, killing mostly children and young adults.

Every three seconds a young child dies - in most cases from an infectious disease. In some countries, one in five children die before their fifth birthday. Every day 3 000 people die from malaria - three out of four of them children. Every year 1.5 million people die from tuberculosis and another eight million are newly infected.

Behind each of these deaths lies a human tragedy. Because these diseases affect mainly young children and adult breadwinners, their impact on families can be catastrophic. Children may lose one or both parents to an infectious disease. The AIDS epidemic alone has left over eight million children orphaned. To make matters worse, families risk being driven into debt through lost earnings and high health care costs - trapping them in a vicious circle of poverty and ill-health.

Pneumonia
Acute respiratory infections (ARIs) are responsible for many deaths. Pneumonia, the deadliest ARI, kills more children than any other infectious disease. Most of these deaths (99%) occur in developing countries. Yet in industrialized countries childhood deaths from pneumonia are rare.
Pneumonia often affects children with low birth weight or those whose immune systems are weakened by malnutrition or other diseases. Without treatment, pneumonia kills quickly.
The influenza virus is another cause of pneumonia. There is very little information available on the number of influenza deaths in developing countries. However, in the United States alone, the disease kills 10 000-40 000 people in an average influenza season.

HIV/AIDS
Over 33 million people are living with HIV/AIDS worldwide. There is still no cure on the horizon. Worst affected is sub-Saharan Africa. In some countries, up to one in four of the adult population are now living with HIV/AIDS. In Zimbabwe, 20%-50% of pregnant women in some areas are infected with HIV and risk infecting their children. An increasing number of maternal deaths are now due to infections contracted by HIV-positive women during delivery. In many countries, life expectancy and child survival rates have plummeted. In Botswana life expectancy at birth has fallen from 70 to around 50 years.

Diarrhoea
Diarrhoeal diseases claim nearly two million lives a year among children under five. They are so widespread in developing countries that parents often fail to recognize the danger signs. Children die simply because their bodies are weakened often through rapid loss of fluids and undernourished through lack of food.

Diarrhoeal diseases impose a heavy burden on developing countries - accounting for 1.5 billion bouts of illness a year in children under five. The burden is highest in deprived areas where there is poor sanitation, inadequate hygiene and unsafe drinking water.
In certain developing countries, epidemics of diarrhoeal diseases such as cholera and dysentery strike down adults and children alike. Other major diarrhoeal diseases include typhoid fever and rotavirus which is the main cause of severe dehydrating diarrhoea among children.

Tuberculosis (TB)
Tuberculosis, a disease once thought to be under control, has bounced back with a vengeance to kill 1.5 million people a year - even more when in combination with HIV/AIDS. Nearly two billion people - one-third of the world's population - have latent TB infection. Together they constitute a huge potential reservoir for the disease. TB kills more adolescents and adults than any other single infection. It is also a leading cause of death among women.

To make matters worse, infection with HIV weakens the immune system and can activate latent TB infection. It is also believed to multiply the risk of initial infection with TB. About one-third of all AIDS deaths today are caused by TB.

Malaria
Malaria kills over one million people a year - most of them young children. Most malaria deaths occur in sub-Saharan Africa, where malaria accounts for one in five of all childhood deaths. Women are especially vulnerable during pregnancy. They are more likely to die from the disease, suffer miscarriages or give birth to premature, low-weight babies.

Malaria can rapidly overwhelm a young child causing high fever, convulsions and breathing difficulties. With the onset of cerebral malaria - an acute form of the disease - the child lapses into a coma and may die within 24 hours.

The high incidence of malaria cases - over 275 million a year globally - can impose a huge economic burden on both families and governments through lost productivity, missed education and high health care costs.

Measles
Measles is the most contagious disease known to man. It is a major childhood killer in developing countries - accounting for about 900 000 deaths a year. The measles virus may ultimately be responsible for more child deaths than any other single microbe - due to complications from pneumonia, diarrhoea and malnutrition.