Caitlin Rivers' Outbreak Outlook - National - 4/1

Here's excerpts from the latest newsletter from Dr Caitlin Rivers, who was also mentioned in a Washington Post article today about bird flu (H5N1).

Outbreak Outlook - National - April 1
Flu and Covid-19 down, but I'm watching H5N1 closely

"ILI: Influenza-like illness is on its way out across the country. Nationwide, 3.2% of outpatient visits are for fever and cough or sore throat, down from this season’s peak of 6.3%. The baseline that marks the beginning and end of flu season is 2.9%, so I expect we will reach it in one to two weeks. 

"COVID: Covid-19 activity is also declining. The rate of new weekly hospitalizations is headed toward 2 per 100,000, which is generally the low point for the year. Wastewater concentration for SARS-CoV-2 is also steeply declining, both at the national level and across all four regions of the country.

"OTHER BUGS:  Seasonal coronavirus activity is down, bringing welcome relief as we move into allergy season (the fewer causes of stuffy noses, the better). The seasonal coronaviruses cause cold-like symptoms. It looks like this year’s peak was in February.

"Human metapneumovirus activity is rising; last year saw an early April peak, and this year looks like it might be similar. Metapneumovirus is a respiratory pathogen known to cause symptoms ranging from mild cold-like signs to severe lung infections, especially in children, the elderly, and immunocompromised individuals. The Southern, Midwestern and Western regions are also seeing rising activity.

"Parainfluenza and adenovirus look fine.

"STOMACH BUGS: It continues to be peak norovirus season, with test positivity rising in most regions of the country. The only exception is the Northeast, which is finally seeing slight easing. At the national level, test positivity rose this week from 11.9% to 13.2%. Nationwide peak occurred in mid-April last year, so we likely have several weeks yet to go.

"IN OTHER NEWS: U.S. officials have detected avian influenza A(H5N1) in dairy cows in New Mexico, Texas, Michigan, Idaho and Kansas. H5N1 has been spreading widely in wild birds for several years now, as I’ve reported in previous newsletters. Symptoms in dairy cows include reduced milk production and low appetite. This development follows a recent report of goats contracting bird flu in Minnesota, which marked the first known instance of the virus in domestic ruminants. The U.S. Department of Agriculture and the Food and Drug Administration have determined that the commercial milk supply remains safe, because milk from sick animals is discarded. Moreover, pasteurization is effective at inactivating viruses and bacteria.

    "This situation is worrisome because it affects multiple farms across different states and includes infections in animals not previously affected. While there are clear implications for agriculture, my major concern is the potential for the virus to evolve to spread easily between humans. There is no evidence that this is happening, but any time we see a change in the epidemiology of the virus, I take notice. I’ll be watching this situation closely in the days and weeks ahead."

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From the Washington Post article today: Bird flu detected in person who had contact with infected dairy cattle in Texas

"A person in Texas is being treated for bird flu, the second human case of an illness caused by a highly virulent virus that has rampaged through sickened dairy cows in five states in recent weeks, federal and state officials said Monday.

"The patient, who experienced eye inflammation as their only symptom, was tested for flu late last week with confirmatory testing performed by the Centers for Disease Control and Prevention over the weekend. The patient is being treated with the antiviral drug oseltamivir. The case does not change the risk for the general public, which remains low. The person had direct exposure to dairy cattle presumed to be infected with avian influenza, Texas officials said Monday.

"The case has alarmed disease trackers monitoring for the worst-case scenario: human-to-human transmission of the pathogen, which has happened infrequently worldwide and typically among family members engaged in work with animals. And it raises questions about whether this pathogen is now more easily transmitted among mammals.

"But federal officials said the infection does not change the bird flu human health risk assessment for the U.S. general public, which the CDC considers to be low. However, people with close or prolonged, unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection.

"Still, any time the virus changes — its recent emergence in cattle and the likelihood of cow-to-cow transmission represents a change — “that makes me sit up and take notice,” said Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security.

"There are several ways the virus could evolve, disease experts have said: It could remain primarily a threat to animal health and then recede, as it has in the past. It may continue circulate among animals, but not routinely infect humans. Or, in the worst case, it evolves to spread easily between people and becomes the next pandemic, Rivers said.'"

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Let the minimizing begin! Just read some of the Post article's reader comments to see for yourself.