“Previously … CDC developed tests for emerging pathogens and then shared those tests with others, and then after that, commercial labs would develop their own tests,” Shah told CNN. “That process took time. Now with these new arrangements, commercial labs will be developing new tests for public health responses alongside CDC, not after CDC.”
In a news release announcing the contract, ARUP Laboratories also characterized the move as a shift for the agency.
“The new contract formalizes ARUP’s relationship with the CDC,” said Benjamin Bradley, MD, PhD, medical director of the ARUP Institute for Research and Innovation in Infectious Disease Genomic Technologies, High Consequence Pathogen Response, Virology, and Molecular Infectious Diseases. “We continue to expand our capabilities to address public health crises and are prepared to scale up testing for H5N1, or develop other tests quickly, should the need arise.”
“To be clear, we have no evidence so far that this [bird flu] virus can easily infect human beings or that it can spread between human beings easily in a sustained fashion,” Jennifer Nuzzo, DrPH (above), Director of the Pandemic Center and Professor of Epidemiology at Brown University School of Public Health, told CNN. “If it did have those abilities, we would be in a pandemic.” Clinical laboratory leaders will recall the challenges at the CDC as it developed its SARS-CoV-2 test early in the COVID-19 pandemic. (Photo copyright: Brown University.)
Missouri Case Raises Concerns
The first human infection of HPAI was reported in late March following a farmer’s “exposure to dairy cows presumably infected with bird flu,” the CDC stated in its June 3, 2024, bird flu Situation Summary. That followed confirmation by the USDA’s Animal and Plant Health Inspection Service (APHIS) of an HPAI outbreak in commercial poultry flocks in February 2022, and the CDC’s confirmation of the first known infections in dairy herds reported on March 25, 2024.
Concerns about the outbreak were heightened in September following news that a person in Missouri had been infected with the virus despite having no known contact with infected animals. CNN reported that it was the 14th human case in the US this year, but all previous cases were in farm workers known to be exposed to infected dairy cattle or poultry.
In a news release, the Missouri Department of Health and Senior Services (DHSS) revealed that the patient, who was not identified, was hospitalized on Aug. 22. This person had “underlying medical conditions,” DHSS reported, and has since recovered and was sent home. Both DHSS and the CDC conducted tests to determine that the virus was the H5 subtype, the news release states.
At present, the CDC states that the public health risk from the virus is low. However, public health experts are concerned that risks could rise as the weather gets cooler, creating opportunities for the virus to mutate “since both cows and other flu viruses will be on the move,” CNN reported.
Concerns over CDC Testing and FDA Oversight
In the months immediately following the first human case of the bird flu virus, Nuzzo was among several public health experts sounding an alarm about the country’s ability to ramp up testing in the face of new pathogens.
“We’re flying blind,” she told KFF Health News in June, due to an inability to track infections in farmworkers. At that time, tests had been distributed to approximately 100 public health labs, but Nuzzo and other experts noted that doctors typically order tests from commercial laboratories and universities.
KFF reported that one diagnostics company, Neelyx Labs, ran into obstacles as it tried to license the CDC’s bird flu test. Founder, CEO, and lead scientist Shyam Saladi, PhD, told KFF that the federal agency had promised to cooperate by facilitating a license and a “right to reference” CDC data when applying for FDA authorization but was slow to come through.
While acknowledging the need for testing accuracy, Greninger contended that the CDC was prioritizing caution over speed, as it did in the early days of the COVID-19 pandemic. “The CDC should be trying to open this up to labs with national reach and a good reputation,” he told KFF.
Another problem, KFF reported, related to the FDA’s new oversight of laboratory developed tests (LDTs), which is causing labs to move cautiously in developing their own tests.
Jennifer Nuzzo, DrPH (above), Director of the Pandemic Center and Professor of Epidemiology at the Brown University School of Public Health co-authored a June 2024 analysis in Health Affairs that called on the CDC to develop “a better testing playbook for biological emergencies.” The authors’ analysis cited earlier problems with the responses to the COVID-19 and mpox (formerly known as monkeypox) outbreaks.
If global surveillance networks have detected a novel pathogen, the authors advise, the US should gather information and “begin examining the existing testing landscape” within the first 48 hours.
Once the pathogen is detected in the US, they continued, FDA-authorized tests should be distributed to public health laboratories and the CDC’s Laboratory Response Network (LRN) laboratories within 48 hours.
Advocates of this approach suggest that within the first week diagnostics manufacturers should begin developing their own tests and the federal government should begin working with commercial labs. Then, within the first month, commercial laboratories should be using FDA-authorized tests to provide “high throughput capacity.”
This may be good advice. Experts in the clinical laboratory and healthcare professions believe there needs to be improvement in how novel tests are developed and made available as novel infectious agents are identified.
Though PCR clinical laboratory testing is widely used, some scientists are concerned its specificity may limit the ability to identify all variants of bird flu in wastewater
Wastewater testing of infectious agents appears to be here to stay. At the same time, there are differences of opinion about which methodologies and clinical laboratory tests are best suited to screen for specific contagions in wastewater. One such contagion is avian influenza, the virus that causes bird flu.
Wastewater testing by public health officials became a valuable tool during the COVID-19 pandemic and has now become a common method for detecting other diseases as well. For example, earlier this year, scientists used wastewater testing to learn how the H5N1 variant of the bird flu virus was advancing among dairy herds across the country.
In late March, the bird flu was first detected in dairy cattle in Texas, prompting scientists to begin examining wastewater samples to track the virus. Some researchers, however, expressed concerns about the ability of sewage test assays to detect all variants of certain diseases.
“Right now we are using these sort of broad tests to test for influenza A viruses,” Denis Nash, PhD, Distinguished Professor of Epidemiology at City University of New York (CUNY) and Executive Director of CUNY’s Institute for Implementation Science in Population Health (SPH), told the Los Angeles Times. “It’s possible there are some locations around the country where the primers being used in these tests might not work for H5N1.” Clinical laboratory PCR genetic testing is most commonly used to screen for viruses in wastewater. (Photo copyright: CUNY SPH.)
Effectiveness of PCR Wastewater Testing
Polymerase chain reaction (PCR) tests are most commonly used to distinguish genetic material related to a specific illness such as the flu virus. For PCR tests to correctly identify a virus, the tests must be designed to look for a specific subtype. The two most prevalent human influenza A viruses are known as H1N1 (swine flu) and H3N2, which was responsible for the 1968 pandemic that killed a million people worldwide. The “H” stands for hemagglutinin and the “N” for neuraminidase.
Hemagglutinin is a glycoprotein that assists the virus to attach to and infect host cells. Neuraminidase is an enzyme found in many pathogenic or symbiotic microorganisms that separates the links between neuraminic acids in various molecules.
Avian flu is also an influenza A virus, but it has the subtype H5N1. Although human and bird flu viruses both contain the N1 signal, they do not share an H. Some scientists fear that—in cases where a PCR test only looks for H1 and H3 in wastewater—that test could miss the bird flu altogether.
“We don’t have any evidence of that. It does seem like we’re at a broad enough level that we don’t have any evidence that we would not pick up H5,” Jonathan Yoder, Deputy Director, Infectious Disease Readiness and Innovation at the US Centers for Disease Control and Prevention (CDC) told the Los Angeles Times.
The CDC asserts current genetic testing methods are standardized and will detect the bird flu. Yoder also affirmed the tests being used at all the testing sites are the same assay, based on information the CDC has published regarding testing for influenza A viruses.
Genetic Sequencing Finds H5N1 in Texas Wastewater
In an article published on the preprint server medRxiv titled, “Virome Sequencing Identifies H5N1 Avian Influenza in Wastewater from Nine Cities,” the authors wrote, “using an agnostic, hybrid-capture sequencing approach, we report the detection of H5N1 in wastewater in nine Texas cities, with a total catchment area population in the millions, over a two-month period from March 4th to April 25th, 2024.”
The authors added, “Although human to human transmission is rare, infection has been fatal in nearly half of patients who have contracted the virus in past outbreaks. The increasing presence of the virus in domesticated animals raises substantial concerns that viral adaptation to immunologically naïve humans may result in the next flu pandemic.”
“So, it’s not just targeting one virus—or one of several viruses—as one does with PCR testing,” Eric Boerwinkle, PhD, Dean of the UTHealth Houston School of Public Health told the LA Times. “We’re actually in a very complex mixture, which is wastewater, pulling down viruses and sequencing them. What’s critical here is it’s very specific to H5N1.”
Epidemiologist Blake Hanson, PhD, Assistant Professor, Department of Epidemiology, Human Genetics, and Environmental Sciences at the UT Health Houston Graduate School of Biomedical Science, agreed with Boerwinkle that though the PCR-based methodology is highly effective at detecting avian flu in wastewater samples, the testing can do more.
“We have the ability to look at the representation of the entire genome, not just a marker component of it. And so that has allowed us to look at H5N1, differentiate it from some of our seasonal fluids like H1N1 and H3N2,” Hanson told the LA Times. “It’s what gave us high confidence that it is entirely H5N1, whereas the other papers are using a part of the H5 gene as a marker for H5.”
Human or Animal Sources
Both Boerwinkle and Hanson are epidemiologists in the team studying wastewater samples for H5N1 in Texas. They are not sure where the virus originated but are fairly certain it did not come from humans.
“Texas is really a confluence of a couple of different flyways for migratory birds, and Texas is also an agricultural state, despite having quite large cities,” Boerwinkle noted. “It’s probably correct that if you had to put your dime and gamble what was happening, it’s probably coming from not just one source but from multiple sources. We have no reason to think that one source is more likely any one of those things.”
“Because we are looking at the entirety of the genome, when we look at the single human H5N1 case, the genomic sequence has a hallmark amino acid change, compared to all of the cattle from that same time point,” Hanson said. “We do not see that hallmark amino acid present in any of our sequencing data. And we’ve looked very carefully for that, which gives us some confidence that we’re not seeing human-human transmission.”
CDC Updates on Bird Flu
In its weekly updates on the bird flu situation, the CDC reported that 48 states have outbreaks in poultry and 14 states have avian flu outbreaks in dairy cows. More than 238 dairy herds have been affected and, as of September 20, over 100 million poultry have been affected by the disease.
In addition, the CDC monitored more than 4,900 people who came into contact with an infected animal. Though about 230 of those individuals have been tested for the disease, there have only been a total of 14 reported human cases in the US.
The CDC posts information specifically for laboratory workers, healthcare providers, and veterinarians on its website.
The CDC also states that the threat from avian flu to the general public is low. Individuals at an increased risk for infection include people who work around infected animals and those who consume products containing raw, unpasteurized cow’s milk.
Symptoms of H5N1 in humans may include fever or chills, cough, headaches, muscle or body aches, runny or stuffy nose, tiredness and shortness of breath. Symptoms typically surface two to eight days after exposure.
Scientists and researchers have been seeking a reliable clinical laboratory test for disease organisms in a fast, accurate, and cost-effective manner. Wastewater testing of infectious agents could fulfill those goals and appears to be a technology that will continue to be used for tracking disease.
Researchers used CRISPR-based assays to develop new clinical laboratory point-of-care blood test which boasts accuracy, affordability, and accessibility
According to UPI, the test can “distinguish between influenza A and influenza B—the two main types of seasonal flu—as well as identifying more virulent strains like H1N1 and H3N2.”
Many research teams are working to develop paper-based diagnostic screening tests because of their lower cost to produce and usefulness in remote locations. Should this near-patient point-of-care test become clinically viable, it could mean shorter times to answer, enabling speedier diagnoses and earlier start of treatment.
It also means patient specimens do not have to be transported to a clinical laboratory for testing. And reduced cost per test makes it possible to test more people. This serves the public health aspect of monitoring outbreaks of influenza and other diseases and gives hope for improved treatment outcomes.
“Being able to tease apart what strain or subtype of influenza is infecting a patient has repercussions both for treating them and public health interventions, said Jon Arizti Sanz, PhD, co-lead study author and postdoctoral researcher at the Broad Institute of Harvard and MIT, in a Broad Institute news release.
“Ultimately, we hope these tests will be as simple as rapid antigen tests, and they’ll still have the specificity and performance of a nucleic acid test that would normally be done in a laboratory setting,” Cameron A. Myhrvold, PhD (above), Assistant Professor of Molecular Biology at Princeton University in New Jersey, told CIDRAP. Influenza tests that can be performed at the point of care and in remote locations may reduce the number of screening tests performed by clinical laboratories. (Photo copyright: Michael James Butts/Hertz Foundation.)
Her team developed their tests using Streamlined Highlighting of Infections to Navigate Epidemics (SHINE), “a clustered regularly interspaced short palindromic repeats (CRISPR)-based RNA detection platform,” the researchers wrote in their Journal of Molecular Diagnostics paper.
“SHINE has a runtime of 90 minutes, can be used at room temperature and only requires an inexpensive heat block to heat the reaction. The SHINE technology has previously been used to identify SARS-CoV-2 and later to distinguish between the Delta and Omicron variants,” Bioanalysis Zone reported.
“The test uses genetically engineered enzymes to identify specific sequences of viral RNA in samples,” the researchers told UPI. Originally designed to detect COVID-19, the team adapted the technology to detect influenza in 2022 “with the aim of creating a screening tool that could be used in the field or in clinics rather than hospitals or high-tech diagnostic labs,” they said.
Influenza A and B as well as H1N1 and H3N2 subtypes were the targets of the four SHINE assays. “When tested on clinical samples, these optimized assays achieved 100% concordance with quantitative RT-PCR. Duplex Cas12a/Cas13a SHINE assays were also developed to detect two targets simultaneously,” the researchers wrote in their paper.
The team used “20 nasal swabs from people with flu-like symptoms during the 2020-2021 flu season, nasal fluid from healthy people as the control, and 2016-2021 influenza sequences downloaded from the National Center for Biotechnology Information Influenza (NICB) database. They compared the results with those from quantitative reverse transcription-polymerase chain reaction (RT-PCR) tests,” CIDRAP reported.
The original 2020 test (shown above) takes 90 minutes to develop at room temperature. The test developers aim to drop this down to 15 minutes. In comparison, typical polymerase chain reaction (PCR) testing requires medical laboratories to have specialized equipment, trained staff, and prolonged processing times, the Broad Institute news release notes. (Photo copyright: Broad Institute.)
Implications of the New Tests
The ease of the new tests is an important development since approximately only 1% of individuals who come down with the flu see doctors for testing, according to the news release. And researchers had this in mind, looking at speed, accuracy, and affordability as a means to “improve outbreak response and infection care around the world,” UPI reported.
There are great benefits to strain differentiation that be achieved with the new test. Doctors are hopeful the test will help dial in the best treatment plans for patients since some strains are resistant to the antiviral medication oseltamivir (Tamiflu), UPI noted. This is significant since Tamiflu “is a common antiviral,” said Sanz in the Broad Institute news release.
“These assays have the potential to expand influenza detection outside of clinical laboratories for enhanced influenza diagnosis and surveillance,” the Journal of Molecular Diagnostics paper noted. This allows for more strategic treatment planning.
“Using a paper strip readout instead of expensive fluorescence machinery is a big advancement, not only in terms of clinical care but also for epidemiological surveillance purposes,” said Ben Zhang, an MD candidate in the Health Sciences and Technology at Harvard and co-first author of the study, in the Broad Institute news release.
Future Plans for Tests
“With further development, the test strip could be reprogrammed to distinguish between SARS-CoV-2 and flu and recognize swine flu and avian flu, including the H5N1 subtype currently causing an outbreak in US dairy cattle,” the study authors told CIDRAP.
The team is also looking at ways to help prevent H5N1 from crossing into human contamination, Sanz told UPI.
The new Princeton/MIT/Harvard tests echo the trend to bring in affordability and ease-of-use with accurate results as an end goal. Faster results mean the best treatments for each person can start sooner and may render the transport of specimens to a clinical laboratory as a second step unnecessary.
As research teams work to develop paper-based viral tests for their plethora of benefits, clinical laboratories will want to pay close attention to this development as it can have a big implication on assisting with future outbreaks.
Additional research is needed before these tests are going to be commonplace in homes worldwide, but this first step brings inspiration and hope of what’s to come.
