Thirty previously unknown diseases, such as HIV/AIDS, Ebola, hepatitis C, Lyme disease, hantavirus pulmonary syndrome and Severe Acute Respiratory Syndrome (SARS) have emerged in the past 20 years. They remain incurable. These emerging diseases represent a significant cause of suffering and death, and impose an enormous financial burden on society. Studies show that pandemics of new strains of influenza and other emerging diseases are travelling faster and wider than ever before owing to global travel and trade. Some “older” diseases have been effectively controlled with the help of modern technologies, such as antibiotics and vaccines; others, such as malaria, TB and bacterial pneumonia, are now re-emerging in forms resistant to drug treatments (see anti-microbial resistance).