Bird flu makes return to Israel, two months after last recorded case

A seagull was found to be infected with the H5N1 strain of avian influenza at Habonim, north of Zichron Ya'akov, last week, over two months after the last recorded case, according to the Agriculture Ministry.

According to a case report filed to the World Organization for Animal Health (WOAH), an Armenian gull was found dead at the Habonim Beach Nature Reserve on April 9.

The last bird flu case reported in Israel was reported on January 19, when a northern shoveler was found to be infected with the H5N1 strain in Modi'in.

Additional cases of the H5N1 strain were reported in January, December and November in various locations throughout Israel. The first outbreak of the season was reported at a turkey slaughterhouse in Kibbutz Shluhot in northern Israel in November.

In late 2021, a large outbreak of H5N1 avian influenza swept through Israel, with the Agriculture Ministry calling it one of the largest outbreaks in the world.

Additionally, for the first time, the virus caused a mass fatality event among wild birds last year, killing one million birds and 8,000 cranes in 20 hotspots across the country, including Hula Lake.

Ongoing outbreak affecting North, South America and Europe

The new infection in Israel comes amid an ongoing outbreak in North and South America and Europe which began in 2021 and has been described as "the largest-ever" outbreak on both continents.

The outbreak has been widely affecting both birds and mammals. In the US alone, over 58 million poultry have been affected and 6,542 infected wild birds have been found in almost every state. In Europe, hundreds of wild and domestic birds were found to be infected in over 24 countries, with many sea birds affected.

Mass mortality events of sea lions and seals due to avian influenza have been reported in the Americas and Russia due to the bird flu. A large number of foxes, cats, otters, dolphins and other mammals have been killed by the virus as well in recent months.

On March 29, the Chilean Health Ministry notified the World Health Organization (WHO) that a man in the coastal city of Tocopilla had tested positive for the virus and was hospitalized after exhibiting respiratory symptoms. A large number of infected birds and marine mammals were found in the Tocopilla area from December to mid-February.

Three close contacts of the case were asymptomatic and tested negative for the virus. Nine contacts among healthcare workers were identified. While all nine concluded the required monitoring period on April 4, one of them developed respiratory symptoms on April 5 so further testing was conducted and the monitoring period was extended for seven more days.

The source of infection is still being investigated as well.

On Friday, officials from the US Centers for Disease Control and Prevention (CDC) said that two genetic mutations that are signs of adaptations to mammals were found in a sample of the virus from the infected man in Chile, according to the New York Times.

In experimental studies, the mutations, known as the PB2 gene, have been shown to help the virus replicate better in mammalian cells.

The officials stressed that the risk to public health remains low as other genetic changes that are believed to be necessary for H5N1 to spread among humans are still missing.

"To date, HPAI A(H5N1) viruses currently circulating in birds and poultry, with spillover to mammals, and those that have caused human infections do not have the ability to easily bind to receptors that predominate in the human upper respiratory tract," said the CDC in a recent report. "Therefore, the current risk to the public from HPAI A(H5N1) viruses remains low. However, continued comprehensive surveillance of these viruses in wild birds, poultry, mammals, and people worldwide, and frequent reassessments are critical to determining the public health risk, along with ongoing preparedness efforts.”