A lethal bird flu strain, known as D1.1, has infected at least four cattle herds in Nevada, according to the US Department of Agriculture (USDA). The strain, which was also linked to a fatal human case in Louisiana last year, is characterized by respiratory symptoms such as coughing and sneezing.
This discovery upends previous theories that suggested new variants of the virus were not repeatedly spreading into cows from birds. The detection of D1.1 has also led to concerns about worker safety, although it is unclear how many workers may have been exposed to the strain.
Symptoms in humans infected with D1.1 are more severe than those caused by a previous bird flu strain, known as B3.13, which has resulted in only mild symptoms such as pink eye and fever. The risk of disease transmission from animals to humans is different for other animals, such as pet cats, which have frequently died after exposure to contaminated food and milk.
The USDA’s Animal and Plant Health Inspection Service (APHIS) says that the detection does not change its plan to eradicate highly pathogenic avian influenza (HPAI), a surge of which has been caused by spillovers from wild birds into chickens. The virus is also linked to an unprecedented toll on egg production, with nearly 1,000 cow herds confirmed infected across 16 states.
The four new cattle herds infected by D1.1 were reported in Churchill County, Nevada, and two additional herds have been placed under quarantine pending laboratory results. Symptoms of the virus include fever, reduced feed consumption, and mild respiratory signs.
Source: https://www.cbsnews.com/news/cows-bird-flu-d11-symptoms