In my advanced biology class, my teacher annually shows the movie Contagion (2011). Now that I have seen its IMDb profile, I am surprised its rating is 6.8/10–lower than I thought. It is a movie with many plot lines, all centering around a novel virus that is incredibly pathogenic with an estimated 20% lethality rate. Although I concede this movie is imperfect with certain plot lines that haven’t aged well and inaccurate pacing, Contagion is surprisingly insightful (especially given its 2011 release date) about how human society reacts to a global pandemic. Since we have experienced a pandemic ourselves, we can really appreciate the speculative work done by the story writers. There is a character played by Jude Law who immediately begins spreading misinformation online about the disease after news coverage. There are frustrating scenes were epidemiologists and disease experts are discredited and dismissed by political bodies who lack the expertise. This movie is even accurate to how many novel diseases develop: zoonosis, or a virus “jumping” between species, accumulating mutations that allow it to eventually “jump” to humans. I believe it deserves a higher rating because it stirred true fear into me. Even though I had watched it before, the artful cinematography conveys the truly disgusting symptoms of the novel disease and the feeling of inescapability of the virus. I really recommend a watch! It also has small plot-Easter eggs that I had a lot of fun drawing connections between.
My biology teacher, while prefacing the movie, told us that in 2019, he gave his students a current events article about a novel coronavirus outbreak in Wuhan, China right before the movie. Eerily similar to 5 years ago, he showed us a current events article discussing an emergent novel disease: this time being the avian influenza strain H5N1 circulating in Californian cattle. H5N1 has long been noted as a highly-pathogenic strain on avian influenza that has caused outbreaks in the past few decades. However, it simply had not yet acquired mutations necessary for human-human infection, relying on animal-to-human infection to reach us.
Before I begin on the current situation with H5N1, I want to discuss some basic information regarding influenza viruses in general. Influenza is a family of viruses also known as Orthomyxoviridae of segmented RNA viruses. Since RNA is much more unstable than DNA, influenza viruses accumulate genetic changes in a very short time. The “H” and “N” naming system belong to the class of Influenza A viruses, who cause the more dangerous symptoms and have the higher pathogenicity compared to other classes. “H” refers to hemagglutinin and “N” refers to neuraminidase, both proteins on the virus surface. There are currently 18 known hemagglutinin (HA) and 11 known neuraminidase (NA) variants, who are named using the letter of the protein and its identification number, giving the familiar H1N1, H5N1, and H7N9 viruses, for example. Both HA and NA have functional roles in influenza’s replication cycle. HA facilitates viral attachment to mammalian cell-surface glycoproteins containing sialic acid–to which HA binds. NA is the opposite: as newly made viruses bud off of the cell, it desailyates, or cleaves the HA-sialic acid interaction to facilitate viral escape. HA and NA must be in balance for a functioning pathogenic virus: an HA too “sticky” prevents viruses from budding and an NA too “violent” prevents viruses from binding effectively to a cell.
Little changes in HA and NA can also change their affinity for the differing cell-surface receptors on distinct species. Suppose little changes accumulate in bat influenza virus allows it to jump into a new species (for this example, assume bat-to-pig). If the pig is also infected with pig influenza, the multiple RNA segments that makeup the viral genome may get mixed up in the same pig cell: resulting, hypothetically, in a reassortment of HA and NA and other viral proteins. In this example, the driver of viral evolution is not only in an accumulation of single-nucleotide mutations, but also a major change in viral identity through “swapping” genome segments. Influenza’s incredible variability is what makes it so dangerous, and why we need to get a new flu vaccine each year. In the case of H5N1 reassortment with human influenza strains, the virus may gain strong mammalian pathogenicity and human-human transmission. Since we are in the midst of flu season, a reassortment event may be on the horizon, and we may be on the brink of an epidemic.
H5N1 infects the respiratory and gastrointestinal tracts in birds, allowing it to be spread through avian saliva, feces, and mucus. In mammals, it can also infect the respiratory tract and cause systemic infection in other organs. Most human cases present with respiratory symptoms that are common with the flu and conjunctivitis, also known as pink eye. Since 1997, diagnosed cases of H5N1 from 23 countries show that the virus has a case fatality proportion of 50%, meaning more than half of people diagnosed with the disease die (CDC). A small timeline of recent H5N1 reports is as follows: since February 2022, H5N1 has been consistently detected in wild birds and commercial poultry. In February of this year, researchers detected H5N1 in Adélie penguins in Antarctica. At that moment, Australia was the only continent left without H5N1 cases (Science). In March, Texan officials declared a confirmed case of H5N1 in a Texan farmer, who, of course, spent a lot of time around livestock and therefore exposed himself to the virus (Science). In November, Canadian officials confirmed the first case of H5N1 in a teenager, and that H5N1 had been detected in farms since October (NYTimes). On December 18, California declared a state of public health emergency regarding the virus, allowing the government more “muscle” in preventing widespread outbreak of H5N1 (NYTimes). California’s cattle, especially, has been hit hard by the virus, raising concerns regarding the safety of dairy consumption. On the same day, the CDC also confirmed the first severe case of H5N1 in the US in a patient from Louisiana. Currently, the CDC reports 65 confirmed cases of H5N1 in the US, with 35 from California (Live CDC Case Tracker).
You may be asking, why aren’t we all freaking out about H5N1? In my opinion, we really should be freaking out–but only a little. It should be on our radars, but not treated as some apocalyptical doomsday disease that is about to kill us tomorrow. A good prevention measure is to drink pasteurized dairy products instead of their raw counterparts. Specifically hunters and farmers should take precautions and undergo frequent H5N1 screening. I believe that although circulating in our livestock, H5N1 not yet having gained human-human transmissibility likely resulted in its general dismissal by the public. Although vaccines have already been tested to be effective, we must be on guard. The Canadian teenager reported in November may have actually been infected with a virus capable of human-human transmission. It is perhaps only that they did not expose others that a Canadian epidemic has not yet begun, according to this Science article.
Given the US’ current political climate, federal response in the event of an H5N1 epidemic has a worrying outlook. Robert F. Kennedy Jr., the new health secretary appointed by President Trump, has long expressed his anti-vaccine views. Although he states he will not block or ban vaccines, I imagine him pulling back vaccine R&D in favor of other medical research areas. Furthermore, America’s anti-vaccination movement has only grown since the COVID pandemic–which would definitely hinder H5N1 vaccination distribution and herd immunity quotas in the event of an H5N1 pandemic. The worst part of these spending and vaccination debates is that they slow the response to a widespread outbreak that is totally preventable. I think one of America’s top priorities at this moment is to separate healthcare from politics: the lives of citizens should not be determined by who is in power at the moment. My ultimate wish is that political differences are set aside to prioritize pandemic prevention, especially since diseases don’t wait for humans to finish arguing.