ON SUNDAY scientists and physicians from around the world will be descending on New Orleans for the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH), the world's leading convention on tropical diseases. The auspiciously timed gathering will include a number of high-profile sessions about Ebola, which promise to aid efforts to contain the disease. So it seems rather odd that an e-mail sent to participants only days before the event warned that anyone who has travelled to Ebola-affected countries within the past 21 days should best stay away. "We see no utility in you travelling to New Orleans to simply be confined to your room," said an e-mail from representatives of the state of Louisiana. It is one of several American states to have imposed a 21-day quarantine on anyone who has recently visited an Ebola-affected country. This restriction will affect scientists from the Centres for Disease Control and Prevention (CDC) and the World Health Organisation (WHO). They include Piero Olliaro, a tropical-disease expert from the WHO, who had been scouting in Guinea for sites to run clinical trials of Ebola drugs. He was supposed to be co-chairing a session, giving two talks and presenting six posters. He is now racing to find someone to replace him.

This is only the latest—and perhaps most egregious—example of “Ebolanoia”, an approach to the disease that prioritises paranoia and politics over medicine and science. In this case the very experts who may have the most wisdom to impart about Ebola are now the ones who are least likely to attend the convention. This is even worse than what happened to Kaci Hickox, a nurse who was placed in quarantine for three days upon returning from treating Ebola in Sierra Leone, despite testing negative for the disease. Her refusal to let herself be stigmatised and locked away has created a tricky problem for politicians who are keen to pander to the panicked.

In part because lawmakers have been all too willing to heed irrational fears (particularly with an election looming), anxieties are mounting. Parents in Oklahoma have demanded a 21-day quarantine for a teacher going to Rwanda, which is nowhere near west Africa. A child in Connecticut has been banned from school because she went to Nigeria. Roselyn Grey, a Liberian-born woman who turned up in a community hospital in Philadelphia with swollen hands and a temperature was sent to the University of Pennsylvania for extensive testing. Often the hysteria has a racial element. Some blacks in America now complain they are being racially profiled.

America was consumed by similar fears in 1987, when anxiety over AIDS led officials to add the virus to the list of diseases that could prevent a traveller from gaining a visa. HIV screening became mandatory for all visa applicants over 14 years old. Motivated by little more than fear, this move inspired so much ill-will that the scientific community gathered for its big international AIDS meeting on foreign turf for more than two decades.

As Ebola rages in three countries, it threatens its neighbours and countries with vast urban populations such as Nigeria, China and India. As long as this is true, America will never be safe. The only way to make America safe is to focus every possible effort on stamping out the plague at source. Creating new fences and barriers—and punishing the very doctors who are doing the most necessary work—is not only foolish, but also counterproductive. America has some of the best-trained doctors and smartest scientists in the world. Without their help, the outbreak is far more likely to spread.

As the CDC makes clear, as long as people have no symptoms, they should be able to travel freely. They are not contagious regardless of where they were or what they saw, and they should not be barred from gatherings. The e-mail from Louisiana acknowledges as much: “From a medical perspective, asymptomatic individuals are not at risk of exposing others”. Given what is at stake, it is wrong to prioritise any other perspective over the medical one. But with an election around the corner—and with Mary Landrieu, the state’s Democratic Senator, struggling to hold on to her seat, and Bobby Jindal, the state’s governor, looking to 2016—long-term solutions are being sacrificed in favour of short-term pandering.