Myxomatosis in the Bay Area

On December 7th, 2023, an outbreak of myxomatosis was confirmed to have been the cause of several deaths of rabbits at an outdoor petting zoo in Berkeley, California, in early November. Read the article from Berkeleyside here.

House Rabbit Society is located here in the San Francisco Bay Area, and many of our members and supporters are local to us.

The Berkeley deaths are the 5th ones attributed to myxomatosis in the Bay Area in 2023. In August, there was a confirmed case in San Jose. In September, there was one in Santa Cruz. In October, there was a confirmed case in Santa Cruz and another in Freedom.

What is myxomatosis?

Myxomatosis is a deadly, viral infection in rabbits caused by a member of the Poxvirus family. It’s endemic to many coastal areas on the west coast of the United States, in the territory of the brush rabbit (Sylvilagus bachmani), which is a reservoir of this disease.

The virus is fatal to domestic rabbits. Currently, there is no treatment or vaccine available in the U.S. Myxomatosis only causes illness in rabbits, not other animals or in people.

How is myxomatosis spread?

Myxomatosis is spread by vectors (mosquitoes, fleas, and ticks) that have bitten an infected rabbit. Direct contact with an infected rabbit can also spread the disease or contact with surfaces contaminated by an infected rabbit. Wild rabbits can carry and spread myxomatosis but may not become sick.

What are the symptoms of myxomatosis?

Symptoms include swollen eyelids, ears, nose, lips, and genitals, a high fever, lethargy, loss of appetite, and progresses to difficulty breathing, and death, within 2 weeks or less. The onset of illness is rapid and sudden death may occur.

If you think your rabbit may have myxomatosis, call your veterinarian immediately and quarantine them away from all other rabbits.

Protecting your rabbit from myxomatosis

House Rabbit Society recommends rabbit guardians in areas where there have been confirmed cases of myxomatosis to house their rabbits indoors (which is also a recommendation due to Rabbit Hemorrhagic Disease Virus Type-2 [RHDV2]), with secure window screens.

Administer a monthly flea treatment to rabbits, to prevent fleas and fur mites. Safe treatments to prevent and kill fleas on rabbits include Advantage (imidocloprid), Program (lufenuron), and Revolution (selamectin). Never use Frontline (fipronil), which is fatal to rabbits.

Prevent mosquitoes from breeding on your property. Regularly check for stagnant water (such as flowerpots, gutters, etc.) and remove any that you find.

Wash your hands before and after handling rabbits, especially ones from outside your home.