What is Valley fever? Experimental vaccine could prevent and treat disease in dogs
An experimental vaccine designed to protect dogs against a certain fungus that causes a disease called Valley fever has proved effective after decades of research.
Valley fever mostly affects dogs’ lungs when they inhale particles of the Coccidioides posadasii fungus from the ground. Canines may initially experience coughing, fever and lack of energy, but the infection can spread to their bones and other organs, causing a deluge of other more serious symptoms.
A study showed the vaccine, plus a booster a month later, “prevented or greatly reduced” Valley fever in dogs. Any lingering symptoms were considered “clinically irrelevant,” according to a news release on research published Oct. 23 in the journal Vaccine.
A single dose did not offer protection against the disease, researchers said, suggesting the booster shot is needed. It’s unknown how long protection will last, given this is the first study to test a canine vaccine for this disease.
The potential vaccine’s early success “is a large step forward toward meeting the licensing requirements” for a Valley fever vaccine for dogs — and for people who can also be infected with the disease-causing fungus, according to the team at the University of Arizona with the Valley Fever Center for Excellence.
“The idea of a vaccine to prevent Valley fever has been the holy grail since the 1950s,” Dr. John Galgiani, director of the UArizona Valley Fever Center for Excellence and a professor of medicine, said in the news release. “We created a vaccine that worked. The dogs had all sorts of laboratory evidence of active, very widespread disease, and the vaccine prevented it.”
The vaccine contains a live strain of the fungus that does not cause disease. A total of 30 beagles and beagle mixes were included in the study; all were injected with the fungus in a laboratory setting and some were given the vaccine.
Where is Valley fever mostly found?
The disease dominates the West coast, with two-thirds of all Valley fever infections in the U.S. occurring in Arizona, mostly in Phoenix and Tucson. California also has its fair share of cases; the disease is often nicknamed the “California disease, desert rheumatism or San Joaquin valley fever.”
The soil-dwelling fungus has also adapted to live in Nevada, New Mexico, Texas, Utah and Washington, as well as northwestern Mexico and parts of Central and South America.
Is Valley fever contagious?
The disease cannot be directly spread between people, from animals to people, or from people to animals. So, if your dog has Valley fever, other pets and family members are not at risk of getting infected.
Both people and dogs can develop the disease if they inhale fungal spores that turn into a “yeast-like organism that infects the lungs,” meaning dogs are naturally more likely to get infected because they could sniff contaminated dirt.
The fungus can exist as mold in dry environments, but once humidity looms, the fungus grows and produces infectious spores, according to VCA animal hospitals. These spores become airborne when winds, farming or construction disturbs the soil.
Valley fever can also infect cats, cattle, horses, deer, apes, kangaroos, tigers, bears, fish, elk, otters and monkeys.
What happens to dogs with Valley fever?
Most infected dogs will recover if they have what veterinarians call “primary disease,” which is when the fungus affects only the lungs. Symptoms such as dry cough, fever, depression and lack of appetite usually appear about three weeks after infection.
But a small number of dogs who go on to develop “disseminated disease” will die. This is when the fungus spreads to other parts of the body, including the bones and joints, causing weight loss, painful limbs, eye infections and seizures.
Typical treatment involves antifungal medications taken over six to 12 months.
What is Valley fever like in people?
Most people who inhale the fungus that causes Valley fever do not get sick, but those who do will recover on their own within weeks to months, some with the help of antifungal medication, the Centers for Disease Control and Prevention says.
One infection is usually enough to confer immunity to the disease, though some people’s infection may relapse, “but this is very rare,” the CDC notes.
In 2019, there were more than 18,400 cases of Valley fever in people reported to the agency, most of which were based in Arizona and California. Experts think the number of Valley fever cases are underestimated because many people are misdiagnosed and never tested for the disease.
In some areas with lots of the fungus, Valley fever is estimated to cause 15% to nearly 30% of pneumonia cases, according to the CDC.
Adults over 60 years old are at the highest risk of getting infected, along with pregnant people, those with diabetes, and Black and Filipino people. Those with weakened immune systems, such as people with HIV and those who have had organ transplants, are also at risk of contracting Valley fever.
This story was originally published October 28, 2021 at 12:46 PM with the headline "What is Valley fever? Experimental vaccine could prevent and treat disease in dogs."
