More than 5,000 different types of viruses - tiny bits of genetic material coated by protein that can infect any cell - have been identified since the tobacco mosaic virus was discovered 109 years ago. But when Volker ter Meulen was a newly minted graduate of the University of Gottingen's medical school and wanted to find out how viruses cause disease, he found no suitable place to study them in Europe. Ter Meulen, now the 69-year-old president of the German Academy of Sciences and one of the world's leading experts on measles, decided to go to the US and work at the Children's Hospital in Philadelphia. Since 1969, a highly effective and safe measles vaccine has been available, but there are outbreaks from time to time in the Western world - including one in Israel that infected nearly 1,000 children, sent 150 of them to hospital and nearly killed a nine-year-old. Despite the vaccine, measles is endemic in the developing countries, and deadly where children suffer from malnutrition and live under crowded conditions. Annual deaths from measles have decreased from nearly 900,000 a decade ago to 345,000 in 2005. In Africa, deaths declined by 75%. But there is still a lot to learn about measles, ter Meulen told The Jerusalem Post in an interview last week at the Israel Academy of Sciences and the Arts in Jerusalem, where he attended the academy's four-day conference on "Neurobiology of Neuro-Psychiatric Diseases" attended by 120 experts from the US, Japan, Switzerland, Hungary, Austria, Germany and Israel and co-sponsored by the two national academies. The meeting was held to mark Israel's 60th anniversary and the 48th since the first historic encounters between then-prime minister David Ben-Gurion and German chancellor Konrad Adenauer. THE GERMAN academy, originally named Academia Naturae Curiosorum in 1652, was founded by four physicians and 18 years later began to publish the world's first medical and scientific journal. In 1677, the emperor of the Holy Roman Empire - Leopold I - recognized the society, which was later called "The Leopoldina." The seat of the president was always in different cities, said ter Meulen, who is its 25th president. In the old days, the president was lifted up to nobility and even had the right to turn an "illegitimate" child into a "legitimate" one, he noted. "The academy head also had the privilege of publishing or saying anything he wanted without censorship. But in the Middle Ages, he had to shut up, as the ruler determined what you were allowed to say until Napoleon brought an end to the Holy Roman Empire. Then, in 1806, all the academy members' privileges were lost." Its senate is comprised of 1,300 unpaid members (6% of them women, compared to 7% in the Israel academy), but only those up to 75 are counted. "Older members have all their rights except that they give their seat away." Today, the German academy continues to advise policymakers and educate society in general on scientific issues. "The government asks, but we can also initiate." ONE OF its most esteemed members was Albert Einstein, who became a member in the 1920s and remained one until he left Germany for the US; ter Meulen needs no persuasion to pose next to the lovely sitting statue of the Jewish genius in the back garden of the Israel academy. The German academy has 28 sections divided among the natural sciences, life sciences, medicine, humanities and social sciences. "We meet annually in different locations, and every two years we hold a large convention. In between," said ter Meulen, "we organize conferences in different universities and symposia on various subjects inside and outside Germany. This is the first one initiated in Israel," added the virologist, who was here 30 years ago and has collaborated with Israeli researchers. "The conference was perfect, with great science and hospitality," he declared. As a young doctor and researcher, ter Meulen might have remained in the US if it hadn't been for the Vietnam War. He and his wife have two children, born in Philadelphia. "I learned to speak English in the US, as I had a very conservative education in Germany and studied Greek instead. As a doctor, I could have been called up to the US army and sent to Vietnam, so I decided to go home to Germany." It isn't clear how viruses originated. Some may have evolved from bacteria while others came from bits of DNA that can move among cells. Only some of them cause diseases, with infection in plants caused by insects that move from plant to plant and in animals by direct or blood contact, the fecal-oral route, coughing and sneezing, blood contact or sex. Fortunately, immune responses that develop in infected animals can also be produced by vaccines. But there are as yet no effective vaccines against all viral diseases including AIDS. Antibiotics are ineffective in killing viruses, but various antiviral drugs are available to fight life-threatening infections. Ter Meulen was unaware of - but very interested in - the fact that Israel had one of the biggest outbreaks of measles in the Western world from the summer of 2007 and ending only a couple of months ago. It began with a Satmar hassid in London who came to Jerusalem to attend a hassidic wedding attended by 2,000, including many children. A family physician at the TEREM urgent care clinic found inconclusive symptoms, but when he checked whether there was a measles outbreak in the Jewish neighborhood in London and found there had been, he reported the case to the Health Ministry. As only about 85% of haredi children are immunized, while families are large and apartments crowded, this sector was a fertile field for the spreading of measles. "It's a universal phenomenon," said the German scientist. "If there is no compulsory vaccination, some parents don't take their kids for shots. In East Germany before unification, immunization was compulsory, but now parents can refuse so their childen can go through natural infection to, they claim, get the immune mechanism to work. Some people don't believe in science-based medicine, but immunization is the greatest achievement of modern medicine." IN THE US, however, while it is not compulsory, there are summer camps, schools and kindergartens that refuse to accept unvaccinated children. So most pediatricians know measles only from textbooks. "When I went to medical school in Germany in 1955, there was an outbreak of polio with 65,000 cases of paralysis, even though there was a vaccine already. Clinical signs show up in only 1% of those infected. It spread at tremendous speed. Polio victims were put into iron lungs and people died. I probably survived polio infection but was lucky not to suffer paralysis." Measles too has lots of complications, he continued. It affects the heart and lungs - encephalitis of the brain is the worst. A third to a half of children with encephalitis die. "I remember when measles went from Switzerland to Germany; children were infected when they were in their pediatrician's waiting room. It's foolish not to vaccinate your children. You need immunization - at age one and then a booster when they finish kindergarten - to protect against an outbreak." The world could eliminate measles, ter Meulen said, as the only host is human beings; monkeys can get measles from man, but man cannot get it from other animals. But to rid the world of it - as with smallpox - you have to vaccinate. It's unfair that parents decide for their child that he will not be vaccinated, but in most cases it is the child who pays. "The better off a society is, the more rejection there is of the principles of medicine - but governments resist making immunization compulsory due to their fear of lawsuits," said ter Meulen. "The claims that measles vaccine can cause autism - which has now been officially disproved - are nonsense." WHEN ter Meulen returned to Germany from the US, he became a hospital pediatrician and treated an eight-year-old who had an "unknown disease" in 1966. The symptoms were chronic encephalitis with paralysis. After eight months of deterioration, the child died. "I was convinced that it was a viral disease, but colleagues were skeptical. I got permission to remove the brain for testing - and sure enough, it turned about to be a virus - measles, which my patient had contracted at the age of one and a half. I wanted to know how the virus got to the brain." Although a virologist, he preferred to devote his life to in-depth measles research rather than looking into a variety of dangerous viruses from malaria and polio to HIV or bacteria, which are 100 times bigger. "A virus is small but one can spend a lifetime studying it. A virus is the best vehicle for transferring genetic information from one cell to another. Viruses can change genes and some, such as human papilloma virus or the hepatitis B and C viruses, can cause cancer. A fifth of human cancers may be caused by viruses, which are very smart." Ter Meulen bemoans the fact that it is rare for pharmaceutical companies to invest in new vaccines. "What they would earn doesn't cover the cost of research. Developing new antibiotics is also very costly and not profitable. Vaccines and antibiotics can never be a blockbuster like drugs that treat chronic conditions. Funny that people never complain about the side effects of a drug like Viagra, but they do complain about vaccines' alleged side effects." Ter Meulen is chairman of the European Academy of Science's advisory council. It has published a recommendation to the EU Council to guarantee a certain level of income to pharmaceutical companies if they develop new vaccines, such as one against malaria. The lack of new vaccines is a big problem, as they are especially needed in developing countries. He noted that the existing measles vaccine could be improved by making it stable in heat. "Then it could be brought to hot countries and not need refrigeration; more children would then be saved. And lots of other viruses need vaccines to defeat them, like cytomegalovirus, ebola virus and HIV. Tax benefits for the companies are not enough; they need a guaranteed income from the sales of effective new vaccines." Ter Meulen concluded the interview by saying that he feels "very good to be in Israel. I admire how you have managed to live here despite all the wars and problems, and to accomplish so much. "Germans admire you. They well know what happened in the Holocaust, and there is no anti-Israeli phenomenon in our media." He recalled that as a young German doctor working in the US a decade after the Holocaust, "there were Jews who refused to speak to me because they had really suffered at the hands of the Nazis. It was understandable then, but fortunately this doesn't happen anymore."