Shamonda Virus Transmits from Livestock to Humans for the First Time

Arabia.net – France recorded its first known human infection with the “Chumonda” virus, which affects livestock, after a man in his sixties with leukemia died on October 9, 16 days after the onset of neurological symptoms including blindness and confusion.

The case followed an initial outbreak of the virus among livestock in Europe, first detected last July. Researchers emphasize that the risk of human-to-human transmission remains low.

The man lived in a rural area of the Rhône-Alpes region, where the virus had been detected in livestock herds. He is believed to have been infected through a bite from a horsefly.

Shortly after symptoms appeared, the patient began experiencing seizures and convulsions, then fell into a coma requiring mechanical ventilation. His condition did not improve despite treatment with antibiotics, an antiviral drug, and high doses of corticosteroids, leading to the discontinuation of life support.

Researchers believe the man’s severely weakened immune system may have exacerbated the disease. They suggest that immune suppression allowed the virus to persist in the body longer, increasing the likelihood of it crossing the blood-brain barrier and causing fatal brain inflammation. Post-mortem samples taken from the brain, liver, and spleen showed high levels of the virus.

Routine blood tests do not detect the “Chumonda” virus, so doctors had to sequence all RNA and DNA in the samples. The virus was found in the cerebrospinal fluid, and its genome closely matched that of the virus isolated from animals. However, the strain found in the man carried five genetic mutations not observed in any animal sequences. Researchers say it is not yet clear whether these mutations make the virus more capable of infecting humans.

The virus belongs to the “pathogenic bunyavirus” family, which infects animals such as cattle and deer and is transmitted via mosquitoes and horseflies, according to Chris Huggins, a researcher in infectious diseases at the University of Queensland in Australia. He noted the absence of vaccines and antiviral treatments for this family of viruses.

Daniel Roll, a virologist at the Kimer Berghefer Institute for Medical Research, said that detection of these viruses in humans is increasing. Climate change, increased contact between wildlife, livestock, and humans, and a growing number of immunocompromised individuals are factors that have raised infection risks. No cases of human-to-human transmission of these viruses have been recorded previously, but transmission from pregnant women to their fetuses was reported during the 2024 outbreak of the “Oropouche” virus in Brazil.

Roll expects French health authorities to intensify monitoring of horseflies following this case, suggesting that the actual number of people infected with bunyaviruses is likely higher than reported, as diagnosis is costly and time-consuming.