thank you.

According to wikipedia: "The true fatality rate may be lower because some cases with mild symptoms may not have been identified as H5N1".

Effectively, only the most extreme cases result in a visit to a medical professional where they figure out what it is and treat it. Otherwise for everyone else, they just get sick with what's seemingly a flu and recover without severe issues, and it isn't recorded as a H5N1 case.

Stop the spread now:

>> California has recently seen a significant rise in detections of H5N1 in dairy herds. Experts believe that animals at as many as half the dairy farms in California are infected. That is why it is important to pasteurize milk, which kills the virus. (All milk sold across state lines is pasteurized; 30 states allow the in-state sale of nonpasteurized milk, which is labeled “raw.”)

>> Two states, Colorado and Pennsylvania, have agreed to test pooled milk from all farms before pasteurization to monitor spread. Bulk milk testing should be mandatory in all states with dairy farms to determine the full extent of the infection on these farms and also allow us to contain the virus. As if to underline the importance of such a mandate, bird flu was detected in raw milk bought retail last Thursday from a dairy producer based in Fresno, Calif.

In such a way that they rarely spread infectious diseases to humans, fwiw.