In a recent news article, it was announced that scientists had found an experimental drug that was effective in mouse models against the Junin virus, a New World Arena virus. Junin causes Argentine hemorrhagic fever, which currently has to drug to treat it. Between 10 and 50 people are infected with the virus every year in Argentina, and the virus is carried by certain rodents. Humans can become sick if they come in contact with contaminated droppings, urine, or saliva. The current treatment is a plasma transfusion from someone who has survived the disease and built up antibodies against the virus. Mapp Bio, the company that developed ZMapp for Ebola, developed an experimental monoclonal antibody to Junin. It was isolated from mice exposed to a key Junin protein, then genetically altered to make it like a human antibody.
It was tested in guinea pigs, it prevented death in all of the animals when started within 6 days. When given on day 7, 92% survived.
However, it seems unlikely that this will come to humans any time soon, as drug development is very expensive, and the disease is underfunded and affects very few people. This illustrates the orphan drug problem, as it is not a lucrative move for the company to go forward with billion dollar human trials in order to develop the vaccine. Hopefully, however, if there is a significant outbreak of Junin, we have a tool to combat it!