The Centers for Disease Control and Prevention (CDC) said on September 20 that Missouri’s ongoing investigation into a recent H5N1 avian flu infection involving no known animal contact has turned up a second health worker who had symptoms, but wasn’t tested.

The CDC said the second health worker wasn’t tested, because his or her illness had resolved before the investigation began. The initial case involved a patient with underlying health conditions and was hospitalized for chest pain, gastrointestinal issues, and other symptoms. A respiratory panel done during hospitalization was positive for influenza A and was later subtyped as H5. Follow-up analysis determined that the virus was H5N1 and similar to the strain infecting dairy cattle, though the patient had no known exposure to cows or other sick patients.

Last week, the CDC said Missouri officials had identified two symptomatic contacts, the patient’s household contact and the first health worker.

In its update, the CDC added that blood samples from the Missouri patient and the household contact have been collected by Missouri health officials and will be sent to the CDC for serologic testing. The first health worker tested negative for influenza in an earlier test, and serological testing will be offered to the second health worker.

CDC and Ohio partners launch serosurvey in veterinary workers

In a related development, the CDC said it and staff from the Ohio Department of Health last week launched a serosurvey of bovine veterinary workers who attended the American Association of Bovine Practitioners (AABP) annual conference in Columbus, Ohio. 

The groups enrolled 150 attendees across 45 states who have worked with cattle in the last 3 months. Participants completed a survey that included questions on exposure, personal protective equipment use, and whether they had experienced flulike symptoms since January. 

The World Health Organization (WHO) said last week that Ghana has notified it of a human H9N2 avian flu case, marking the first zoonotic avian flu case reported from the country.

The patient is a 5-year-old girl who lives near the border with Burkina Faso and who became ill on May 5. Two days later, she was seen at a local hospital and treated for flulike illness. PCR testing on her respiratory sample was positive for H3N2 seasonal flu.

However, genomic testing identified the virus as H9 avian influenza, and additional testing at WHO collaborating centers in the United Kingdom and the United States confirmed the presence of H9N2 on August 6. 

After the subtype was confirmed, regional health officials visited the patient, who was experiencing a new onset of respiratory symptoms. Serum and respiratory samples were negative for flu and the girl has recovered.

No known exposure to poultry

Investigators found that the patient had no known exposure to poultry or people sick with similar symptoms. Samples from close contacts were negative, and no related cases have been detected in the community.

Poultry illnesses have been reported from the region where the girl lives, but the cause hasn’t been confirmed. Ghana has reported low pathogenic H9N2 in poultry since 2017, the WHO said.

H9N2 is known to circulate in poultry, especially in Asia where sporadic infections are reported, mainly in children and mostly mild after exposure to poultry. The WHO said no sustained human-to-human H9N2 activity has been reported.

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today confirmed 18 more H5N1 avian flu outbreaks in dairy cattle, nearly doubling the state’s outbreak total.

California, the country’s biggest dairy producing state, now has the second highest number of outbreaks (34), with Colorado still the state reporting the most outbreaks. The outbreaks have been centered in the Central Valley, and state agriculture officials have been identifying other affected farms due to enhanced surveillance that has focused on those with connections to earlier-affected facilities.

The latest outbreaks push the country’s total number of dairy cow outbreaks to 232 from 14 states since March. 

Virus turns up at Florida poultry market

In poultry outbreaks developments, USDA APHIS confirmed one more outbreak, which involves a live bird market in Florida’s Orange County that has 2,500 birds. Over the past few months, similar outbreaks at live bird markets were reported from two other Florida counties—Hillsborough and Miami-Dade.