Researchers from the U.S. and abroad have developed an inexpensive copper-based filter that may prevent HIV from being passed through breast milk and blood. Worldwide statistics of HIV transmission through breast milk and blood transfusions are at a disastrous high, especially in developing countries. In 2001 breast-feeding was attributed to up to 50% of the 700,000 mother-to-child transmission cases reported. The World Health Organization has estimated that blood transfusions are responsible for 80,000 to 160,000 HIV infections each year, while the Center for Disease Control reports that transfusions are the cause of 5 to 10% of HIV infections in developing countries.