Leptospirosis in Rats

Karen Purcell, DVM
By Karen Purcell, DVM on Jun. 19, 2023
Rat looking out from under plants

In This Article


What is Leptospirosis in Rats?

Leptospirosis is caused by spirochete bacteria of the genus Leptospira. Wild rats are the most common carrier of this disease to pet rats and mice. It is spread from rat to rat directly or by exposure to the blood or urine of infected animals or in contaminated water.

Leptospirosis is a serious risk to humans and other animals. The condition is also referred to as Weil's disease.

Symptoms of Leptospirosis in Rats

Rats usually show no outward signs of infection; however, symptoms may include:

  • Increased drinking

  • Increased urination

Rats can be infected with leptospirosis without becoming ill, but can still spread the disease. Most cases of leptospirosis are only discovered during examination after death.

How Veterinarians Diagnose Leptospirosis in Rats

Leptospirosis is diagnosed by blood testing at a lab or using silver stains to examine urine samples under a microscope. In pet rats, diagnosis is most often confirmed through testing after the rat has passed away.

Treatment of Leptospirosis in Rats

Unfortunately, treatment is not recommended for rats diagnosed with leptospirosis due to the risk of human infection. If a rat has a confirmed diagnosis, a veterinarian will recommend humane euthanization.

Any rat suspected of having leptospirosis is a serious risk to other animals and humans in the home. Your veterinarian will recommend best cleaning practices and how to keep the disease from spreading to your other pets. In addition, pet parents should consult with their own physician to discuss possible exposure to the disease.

Management of Leptospirosis in Rats

Prevention of wild rodents from entering the household is the best way to keep your pets safe from this disease. Keep pet cages up off the floor and away from doors and windows where wild pests may enter. Ensure you are providing the best care to your rats at all times, especially keeping their enclosures clean and providing fresh food and water.

If your rat is suspected of having leptospirosis, gloves, safety goggles, and masks should be worn while cleaning pet rat enclosures to prevent spread of infection. All contaminated bedding should be bagged and discarded carefully. Do not let any other pets near the enclosure or discarded contents of the cage.

While some animals can be vaccinated against leptospirosis, such as dogs and horses, vaccines are not available for small animals at this time.

Leptospirosis in Rats FAQs

Can you get leptospirosis from rats?

Yes, leptospirosis can be carried by otherwise healthy-looking pet rats.

How do you treat leptospirosis in rats?

Treatment is not recommended due to serious risk to humans. Rats suspected of having leptospirosis are often euthanized. If leptospirosis is suspected, pet parents should discuss infection with their physicians as well as the safety of other pets in the household with their veterinarians.

Does rat poop have leptospirosis?

Feces are one source of this disease, along with urine and blood.

Can dogs get leptospirosis from rats?

Yes, wild rodents are a common source for dogs, usually by drinking contaminated water.

Featured Image: iStock.com/Nigel Harris


1. Boey K, Shiokawa K, Rajeev S. Leptospira infection in rats: A literature review of global prevalence and distribution. PLoS Negl Trop Dis. 2019 Aug 9;13(8):e0007499. doi: 10.1371/journal.pntd.0007499. PMID: 31398190; PMCID: PMC6688788.

2. Centers for Disease Control and Prevention. Leptospirosis - Prevention in Pets. 2015.

3. Weese, Scott. Worms & Germs Blog. Weil’s disease from a pet rat. 2009.


Karen Purcell, DVM


Karen Purcell, DVM


Dr. Karen Purcell was born and educated in Troy, NY. She attained her Bachelors in Biology Magna cum laude from Pace University. She...

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