Avian Flu on a Cruise Ship: Can We Do Better on the Mainland?
While on a cruise to the French Riviera in fall 2023, a middle-age woman and her husband took a bike excursion along with 20 other passengers. She felt something land on her right shoulder. She wiped it off with her left hand. It was bird poop. Everyone had finished their supply of drinking water, and no one had hand sanitizer in their backpack.
Two days later she had a cough, high fever, chills, and muscle aches. She checked into the ship’s infirmary. The physician asked: did anything unusual happen in the past few days? Her husband immediately said, yes, she was splattered by bird poop. The physician made a preliminary clinical diagnosis of presumptive avian flu (H5N1) infection.
We don’t know what testing was done, but presumably they had access to rapid antigen testing for COVID, RSV, and influenza A and B. No test for avian flu was available. We also presume that influenza A was positive because H5N1 is a subtype of influenza A. However, since no regular flu was going around, and RSV and COVID had been ruled out, the positive test provided circumstantial evidence for highly pathogenic avian influenza, which was circulating in migratory waterfowl.
She was treated with double-dose oseltamivir (Tamiflu) for 5 days and ordered to isolate. Her husband was given standard oseltamivir prophylaxis and was quarantined with his wife in their cabin. Only the physician and nurse entered the room, and they wore full protective covering, including goggles. Although the woman was acutely sick, she was not transferred off the ship at the next port because she had no comorbidities.
I (Teres) heard this story from the cruise ship patient who gave me permission to share it, but when I contacted the cruise ship to get the medical records, the lawyer for the company that provided the medical care would not release any confirmatory details.
Responding to H5N1 on the Mainland
Avian flu is high on the American public health watch list. It is increasingly found in wild birds, poultry, cows, and many other animals. Some dairy workers are contracting mild cases, and evidence of avian flu is being detected in wastewater surveillance. In August, a more severe case appeared in Missouri with no known source. And in January, a patient in Louisiana with exposure to sick and dead birds in backyard flocks became the first confirmed death in the U.S. Just this week, a new type of bird flu was found in dairy cattle in Nevada. Thus far, there has been no evidence of human-to-human transmission.
Can the effective diagnosis and follow-up treatment provided by the cruise ship, a veritable Petri dish of potential infection, be replicated on dry land? Diagnostic testing is, of course, an important element; yet, we are far from widespread access to rapid and reliable H5N1 tests. And we well remember the impact of the CDC’s inability to facilitate production of a COVID test in the early days of the pandemic. So far, point-of-care clinical diagnostic testing, as opposed to surveillance with genetic sequencing, has not been high on the agenda for H5N1.
Testing for Avian Flu
Our health system currently has a two-step approach to identifying avian flu. Many emergency departments, urgent care centers, and primary care offices are using point-of-care testing that includes three or four of the viral pathogens of concern: COVID, influenza A, influenza B, and perhaps RSV. Some of the influenza A samples — especially those from patients hospitalized or in intensive care and those that test negative for seasonal influenza A virus subtypes — are then sent to one of more than 100 state virology labs with further study for genetic sequencing. This surveillance and testing system takes days. If human-to-human transmission of a deadly strain should occur, a much quicker mode of testing would become imperative.
Shouldn’t our level of awareness and protocols be focused on early detection of “patient zero” (i.e., a case of human-to-human transmission) to contain a local outbreak? Even if subsequent strains become transmissible with mostly “mild” disease, this will ensure we are ready for early detection, early treatment, and the promotion of self-isolation to keep sick people away from the emergency department or urgent care. Elderly and immunocompromised patients benefit from early warning even for “mild” disease.
Time for Rapid Testing
Consequently, we need to have avian flu testing in the front lines. Only two FDA-approved tests are available, according to the most recent list. One is part of the portfolio of the CDC PCR tests — this test has been primarily used in the 100 state virology labs to support the longstanding network that comprises influenza surveillance of hospital cases. The other, called AVantage, is proteomic-based and was developed in 2009 by Arbor Vita as part of pandemic planning for the swine flu outbreak (H1N1). We were told by the company that the test is being ramped up for clinical applicability. A positive result comes up in 15 minutes or less. For a negative, you need to wait 45 minutes to make sure no line shows up.
Because of the steady increase in demand, government funding has been provided for the development of more testing options. Without a doubt, more tests will become available.
Call to Action
We ask state governors and their public health and medical leadership to encourage and sponsor their large healthcare systems, in coordination with state virology labs, to test avian flu within their existing protocols for influenza A, influenza B, COVID, and RSV with a focus on patients with early symptoms (day 1 or 2). In addition, testing for avian flu at the point-of-care might, since the strain is novel, detect cases not identified by the current practice of sending positive influenza A samples to state labs for further testing. This hypothesis needs further evaluation when rapid test production ramps up. Meanwhile, when looking for the breakout case, it is prudent to assume that standard influenza A testing may miss patient zero.
The objective is to gain real-world experience to determine the best methods of early and rapid diagnosis. To this end, additional testing may be required since it is widely recognized that some antigen tests, as opposed to PCR tests, may have an unacceptably high false negative rate in the early phase of infection when viral loads have not peaked. The advantage of antigen testing is its short turnaround time, and the possibility of using it for at-home testing, as became widespread during COVID.
Of course, not all state governments will be receptive. Nevertheless, we simply cannot wait for the federal government to act. Even in states that don’t provide funding, medical centers can take the lead and obtain the available antigen and PCR tests, upgrade their protocols for use in their EDs and associated urgent care and primary care facilities, and share their data with state leadership.
In the event of human-to-human transmission, we must prepare for the worst-case scenario. Healthcare systems will need to minimize patients with suspected avian flu from mixing with other patients in busy waiting rooms — a generator of potential infection, not unlike a cruise ship. As with COVID, healthcare systems will need to establish drive-in or walk-in testing centers.
Our goals are early detection, self-isolation, and early treatment. We hope that vaccines against avian flu will become available in a timely fashion. COVID began as an external threat but, if avian flu progresses, it will start as a local outbreak. We strongly suggest that state leadership takes the responsibility to promote early diagnosis and reduced community transmission.
Daniel Teres, MD, is a retired faculty member of Tufts University School of Medicine in Boston, and critical care physician. Paul C. Sorum, MD, PhD, is professor emeritus of internal medicine and pediatrics at Albany Medical College in New York. Martin A. Strosberg, PhD, is professor emeritus of healthcare policy and bioethics at Union College in Schenectady, New York.
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