When passengers return in the United States since the cruise which saw a rare hantavirus outbreakmuch of the country lacks a basic public health tool: a test to diagnose the disease in the early stages of infection. Nebraska could be the first state to be able to do so.
In just a few days, a laboratory at the University of Nebraska Medical Center in Omaha developed its own diagnostic test for the Andes virus in anticipation of receiving 16 American passengers from the ship.
“I think we may be the only lab in the country that has this test right now,” Peter Iwen, director of the Nebraska Public Health Laboratory, told WIRED, referring to polymerase chain reaction (PCR) tests, which were important during the Covid-19 pandemic. Its ability to detect tiny amounts of virus before patients show real symptoms makes it crucial for quickly identifying cases and obtaining patients rapid medical treatmentand prevent the spread of disease.
The university medical center houses a highly specialized biocontainment unit designed to care for patients with serious infectious diseases who lack vaccines or treatments. Staff members previously treated patients during the 2014 Ebola outbreak and treated some of the first Americans diagnosed with Covid in 2020.
When Nebraska was informed it would welcome some passengers, Iwen contacted the U.S. Centers for Disease Control and Prevention to see if they had testing. He learned that the CDC has the ability to perform a serology test, which looks for the presence of antibodies to hantavirus. But people don’t develop antibodies until they are actively ill and their body has had time to mount an immune response.
Andrew Nixon, a spokesperson for the U.S. Department of Health and Human Services, told WIRED that the CDC has a PCR test for Andes virus, but it is a research test that cannot be used for patient care. Research tests are used in scientific experiments, while diagnostic tests intended to confirm or rule out disease in patients must be rigorously tested or validated to ensure they are capable of producing consistent results. Nixon said the agency is working on validating its PCR test.
Iwen’s lab quickly mobilized to track down the materials needed to build and validate a PCR test from scratch. They called a lab in California – a state that has previously recorded cases of hantavirus – but their test was for a specific strain found in the United States. Andes virus has previously only been detected in South America and is not present in rodents native to the United States.
“The tests we have in the United States will not detect the virus present in South America,” he says, pointing out that the Andes virus is very different genetically from the main strain of hantavirus found in the United States, known as the Sin Numéro virus.
The Nebraska team contacted Steven Bradfute, a hantavirus scientist at the University of New Mexico. Frannie Twohig, a graduate student in Bradfute’s lab, had developed a PCR test for Andes virus for research purposes as part of her doctoral work. Bradfute’s lab also has genetic material from the Andes virus that is not capable of causing disease that the Nebraska lab would need to validate its test.
On Friday, Bradfute shipped genetic material and a box of chemical reagents needed to detect the virus in blood samples to Nebraska overnight. By Saturday morning, Iwen’s team had what they needed to begin assembling and validating their test.
It was enough to carry out around 300 tests, which lasted all day on Saturday and Sunday, explains Iwen. His team added Andean genetic material at various concentrations to healthy human blood samples to see if their test could detect it. Then, they compared the results to control samples. The team has used about a third of its tests for the validation process and now has the capacity to run a few hundred tests on patient samples.
The lab has not yet tested all 16 people in Nebraska’s biocontainment unit, but Iwen hopes to do so soon. He says the goal is to identify cases as early as possible and begin treatment to prevent people from developing serious illness. The Andes virus has a mortality rate of around 35 percent.
“These people will have a very low concentration of blood in their system once they are in the early stages of their disease. That’s the purpose of a test. We want to be able to give an early indication that they are positive,” says Iwen.
Although there is no hantavirus medications Early, immediately available supportive care, such as fluid management and respiratory support, can significantly improve survival rates. Andes virus infects the small blood vessels in the lungs and causes fluid to build up. This causes difficulty breathing and can lead to respiratory failure.
Kelly Wroblewski, senior director of infectious diseases at the Association of Public Health Laboratories, says the state’s capacity for hantavirus antibody testing is limited. A handful of states, primarily those in the southwest of the country, have the capacity to conduct this type of testing. She says several state labs are working to bring PCR testing online, but she doesn’t expect to need the kind of testing infrastructure that was needed at the height of the Covid-19 pandemic, when millions of tests were being performed every day in the United States alone.
“We are currently talking, globally, about a very different virus and a limited number of people exposed,” she says.
In early 2020, the CDC was the only laboratory capable of initially performing Covid testing. The agency developed testing kits to distribute to public health labs across the country, but the rollout was hampered by faulty kits, which hampered early efforts to track the spread of the virus.
“What Nebraska did to withstand a test is one of those lessons learned: Prepare before you even need to take the test,” Wroblewski says.
