Plant Disease Transmission To Humans: Can Virus And Plant Bacteria Infect A Human

Stethoscope Around A Plant
(Image credit: Inna Polekhina)

No matter how closely you listen to your plants, you'll never hear a single “Achoo!” from the garden, even if they're infected with viruses or bacteria. Although plants express these infections differently from humans, some gardeners worry about plant disease transmission to humans -- after all, we can get viruses and bacteria, too, right?

Can Plant Bacteria Infect a Human?

Although it would seem like a no brainer to assume that plant and human diseases are distinct and cannot crossover from plant to gardener, this isn't the case at all. Human infection from plants is very rare, but it does happen. The primary pathogen of concern is a bacteria known as Pseudomonas aeruginosa, which causes a type of soft rot in plants.

P. aeruginosa infections in humans can invade nearly any tissue in the human body, provided they are already weakened. Symptoms vary widely, from urinary tract infections to dermatitis, gastrointestinal infections and even systemic illness. To make matters worse, this bacterium is becoming increasingly antibiotic resistant in institutional settings.

But wait! Before you run to the garden with a can of Lysol, be aware that even in severely ill, hospitalized patients, the infection rate of P. aeruginosa is only 0.4 percent, making it highly unlikely that you will ever develop an infection even if you have open wounds that come in contact with infected plant tissues. Normally-functioning human immune systems make human infection from plants highly improbable.

Do Plant Viruses Make People Sick?

Unlike bacteria that can function in a more opportunistic fashion, viruses need very exacting conditions to spread. Even if you eat fruits from your squash mosaic infected melons, you won't contract the virus responsible for this disease (Note: eating fruits from virus-infected plants isn't recommended -- they're not usually very tasty but won't hurt you.).

You should always cull virus-infected plants as soon as you realize they're present in your garden, since they are often vectored from sick plants to healthy ones by sap-sucking insects. Now you can dive in, pruners blazin', confident that there's not a significant connection between plant diseases and humans.

Kristi Waterworth

Kristi Waterworth was a regular contributor to Gardening Know How for many years, answering countless queries on plant pests and diseases.