By Emily Joshu 

A worrying development in the H5N1 bird flu outbreak occurred last week in Missouri.

For the first time, a patient was diagnosed with the virus who had not come into contact with sick birds, cows or other animals.

The worst-case scenario is that the patient caught it from another person and that the virus has begun silently spreading between Americans.

While this is unlikely, Kruitka Kuppali, MD a spokesperson for the Infectious Disease Society of America and former World Health Organization officer, warned this week: 'This is how pandemics start.'

Experts said situation is 'somewhat similar' to how previous pandemics have started, though insisted 'there's no need to panic' yet.

For example, the 2009 swine flu pandemic was first detected in a similar way - when two children in California were diagnosed with no contact with pigs or each other.

The early Covid outbreak in China also began with cases of a mystery flu-like illness and seemingly no connection began cropping up in Wuhan.

Health officials in Missouri have refused to say how the state's 'patient zero' became infected, only that the risk to the public remains 'low.'

Still, experts are concerned by the case and the lack of transparency.

Raj Dasgupta, MD said 'When health authorities aren't transparent, it can cause problems.

'If people don't get clear information, they might not know what symptoms to look for, what actions to avoid, or how to protect themselves.

'This can cause confusion, spread false information, and create unnecessary fear, making it harder to deal with a potential health threat.

'Health officials need to share clear and accurate information quickly to prevent outbreaks and keep people’s trust.'

The Missouri case was detected through the state’s seasonal flu surveillance system, which keeps track of influenza activity based on testing from symptomatic patients.

Because bird flu does not always cause symptoms, there could be more sick people who never got tested.

Another theory is the patient drank raw milk that was contaminated with the virus.

Raw milk is becoming increasingly popular and studies have shown H5N1 particles can linger in it for up to five weeks if it refrigerated, according to the National Institutes of Health (NIH).

About four percent of Americans - nearly 11 million - consume raw milk and raw cheese, which do not go through pasteurization, a process that uses heat to kill about 99.9 percent of pathogens.

In April, WHO warned that bird flu was detected in 'very high concentrations' in samples of raw milk, but pasteurized milk, which is standard in major retailers, was safe to consume.

In recent years, fitness buffs and wellness influencers have dubbed raw milk a superfood over claims that it contains more vitamins and minerals than pasteurized milk and that it is better tolerated for people with asthma and lactose intolerance.

However, the CDC classifies raw milk as 'one of the riskiest foods' and states that the germs it is could carry 'can pose serious health risks to you and your family.'

Thomas Peacock, MD an influenza virologist at the Pirbright Institute in the UK said: 'The obvious question I would ask is: Have you ruled out that they’re not someone who’s got a big tub of raw milk in their fridge? Because that just seems like such an obvious route for a cryptic infection.'

Lisa Cox, a spokesperson for the Missouri Health Department, said that the patient had not reported consuming raw milk.

However, it's unclear if officials actually investigated this or just asked the patient directly.

Peacock also warned that the patient could have had an outdoor cat, as several barnyard cats have been killed by the virus this year. He noted that if the patient had a cat, it could have drank raw milk from a

Raw milk is not banned in Missouri, though it can only legally be purchased directly from a farm or from farmers market vendors with a permit.

Raw milk isn't the only food carrying a risk.

Darin Detwiler, LPD a food safety expert at Northeastern University in Boston and a former FDA and USDA advisor, previously said that foods with undercooked meat or eggs could also harbor small fragments of bird flu and other deadly illnesses.

He noted that while the risk if 'very low,' fully cooking these foods is essential for killing all pathogens. For example, searing a steak on the outside 'should be good enough to kill a pathogen, even if the inside is not properly cooked,' bird flu could travel to the inner part of the beef.

Detwiler also recommends customers be cautious about eggs that have runny yolks, which includes sunny side up, poached, soft boiled, and over easy.

'In the case of avian flu concerns, eggs should be cooked until both the white and yolk are firm, which ensures that the egg reaches a temperature that is likely to kill any viruses present,' he said.

According to the USDA, eggs should be cooked to at least 160 degrees Fahrenheit (71 degrees Celsius).

Eve Elizabeth Pennie, MD, a general practitioner and medical contributor at Drugwatch, said that 'while bird flu transmission through food isn't standard, following safe food practices is always the best way to protect yourself and your family.'

Dasgupta also noted that while person-to-person transmission is highly unlikely, bird flu spreading this way could pose serious risks of an outbreak.

'If the virus is spreading between people, it might mean it has changed or adapted to spread more easily, which could lead to bigger outbreaks or even a pandemic,' he said.