Could H5N1 Be Closer Than You Think? A Disturbing Case in Missouri!

Could H5N1 Be Closer Than You Think? A Disturbing Case in Missouri!
Could H5N1 Be Closer Than You Think? A Disturbing Case in Missouri!

United States: The United States has encountered over a dozen instances of H5N1 infection among its populace this year alone. Prevailing data suggest that this avian influenza primarily transfers from infected fauna, such as dairy livestock and poultry, to humans rather than through human-to-human transmission.

However, the most recent incident — announced on September 6 by the Centers for Disease Control and Prevention (CDC) — concerned an individual in Missouri who lacked any verifiable contact with infected animals, according to Live Science.

The CDC has reported no evidence of the virus being passed to the individual’s close acquaintances. The agency asserts that “the risk to the general public from H5N1 remains low.” This sentiment held true even after two healthcare professionals who attended to the patient fell ill; one tested negative for influenza, while the other has yet to undergo testing for H5N1 or its antibodies.

“I concur with the CDC’s assessment that the threat remains minimal,” stated Dr. Nahid Bhadelia, the founding director of the Center on Emerging Infectious Diseases at Boston University. “A positive sign is the lack of a surge in flu cases,” she added, as any such increase would be evident through routine monitoring for seasonal influenza. This observation should temporarily allay public anxiety over the possibility of an outbreak.

Nevertheless, Bhadelia, along with another expert, voiced concern to Live Science that the Missouri case may signal that the US is insufficiently monitoring H5N1’s proliferation, raising the specter of a potential epidemic.

Dissecting the Missouri Case

The patient in Missouri was hospitalized in August, representing the 14th confirmed case of H5N1 in the country and the first where there was no traceable link to infected animals in the individual’s professional environment. The patient, who had pre-existing health conditions, experienced a variety of symptoms, including chest discomfort, diarrhea, vomiting, and fatigue. Fortunately, they were not gravely ill during their hospitalization and have since recuperated.

Initial diagnostic tests identified influenza A, a broad category of viruses that encompasses H5N1, as well as seasonal flu strains such as H1N1. However, subsequent tests ruled out the usual subtypes, and further investigation confirmed H5N1 as per Live Science.

In a report released on September 13, the CDC indicated that a partial genomic analysis of the virus had been completed; however, the available genetic material was insufficient for a full sequence. Results revealed a high degree of similarity to viruses currently circulating in cattle, with no significant mutations to facilitate human respiratory infection. Such mutations could lead to human-to-human transmission, but thus far, they remain absent.

Despite these relatively encouraging findings, Bhadelia cautions that those involved in pandemic preparedness should not dismiss the Missouri case as a mere anomaly.

H5N1 has been circulating among avian populations in the US since 2022, and it has crossed over into various mammals, including cattle, since its arrival. Bhadelia pointed out that the Missouri infection likely originated from infected cattle, even though the state had not recorded any cases in its bovine population. Historically, Missouri has documented approximately 600,000 cases of infection among poultry, suggesting that infected herds may have escaped detection.

Seema Lakdawala, an associate professor of microbiology at Emory University and an expert in H5N1, expressed concerns that current testing protocols for cattle are inadequate for mapping the virus’s geographic dispersion.

“The USDA [US Department of Agriculture] isn’t conducting nearly enough testing — period,” Lakdawala told Live Science. “We don’t have a clear picture of how many cows are infected because there’s no widespread testing of dairy farms.” As of mid-July, only 17 of Missouri’s estimated 60,000 dairy cows had been tested, according to reports from The Missouri Independent.

Lingering Uncertainties

The exact source of infection in the Missouri case remains elusive. One possibility, according to the CDC, is the consumption of raw (unpasteurized) cow’s milk, a practice that the agency advises against.

“An infected cow could produce tens to hundreds of millions of infectious viral particles per milliliter of milk,” Lakdawala said. With these animals producing gallons of milk daily, it’s plausible that raw milk might harbor enough virus to infect humans, although it’s currently unclear whether bird flu can be transmitted in this manner. Raw milk, when left on milking apparatuses, could also expose dairy workers to the virus.

While humans could hypothetically serve as another vector for H5N1 transmission, no evidence to date suggests that the virus spreads between people. “One way to clarify the situation would be to conduct serology tests on everyone who came into contact with the patient,” Bhadelia noted.

One household member of the Missouri patient exhibited similar symptoms on the same day but was not tested for influenza. Blood samples from that individual are now undergoing antibody testing. According to Lakdawala, the timing of the illnesses suggests that both the patient and their household contact were likely exposed to the same source rather than transmitting the virus to one another. The CDC shares this perspective.

Public health labs currently focus on testing for H5N1 in individuals exposed to animals suspected of harboring the virus. If detected, samples are forwarded to the CDC for confirmation. The agency has partnered with biotech firms to promote earlier and broader testing capabilities.

Additionally, the CDC has ramped up its monitoring efforts among individuals in regular contact with livestock. Last week, in collaboration with Ohio’s health department, the CDC tested veterinarians for antibodies during a conference. Positive tests would indicate prior H5N1 infection.

Lakdawala believes that the USDA must step up its efforts to better understand how the virus spreads among cattle. “What the USDA needs to do, in my view, is work closely with state veterinarians and agricultural departments,” she said. She suggested that authorities conduct bulk testing of milk tankers at every farm.

Currently, only 50 herds across 14 states participate in the USDA’s voluntary Dairy Herd Status Program, which tests milk tanks weekly. Missouri has yet to enroll.