Leptospirosis is a rare bacterial infection we get from animals. It’s spread through their urine, especially from dogs, rodents, and farm animals. They may not have any symptoms, but they can be carriers.

In most cases, leptospirosis is unpleasant but not life-threatening, like a case of the flu. It rarely lasts more than a week. But about 10% of the time, when you have a severe form of leptospirosis, you’ll get better, but then get sick again. This is called Weil’s disease and it can cause much more serious issues, like chest pain and swollen arms and legs. It often requires hospitalization.

What Causes It?

Leptospirosis is caused by a bacterium called Leptospira interrogans. The organism is carried by many animals and lives in their kidneys. It ends up in soil and water through their urine.

If you’re around soil or water where an infected animal has peed, the germ can invade your body through breaks in your skin, like scratches, open wounds, or dry areas. It can also enter through your nose, mouth, or genitals. It’s hard to get it from another human, though it can be passed through sex or breastfeeding. 

You’re at risk if you spend a lot of time around animals or in the outdoors. You’re more likely to be exposed to it if you have one of these jobs:

  • Farmer
  • Veterinarian
  • Underground worker (you work in a sewer or a mine)
  • Slaughterhouse worker
  • Military personnel

Also, if you raft, swim, or camp near affected lakes and rivers, you could get the disease.

Leptospirosis is more often found in warm climates. And although the bacteria lives all over the world, it’s especially common in Australia, Africa, Southeast Asia, Central and South America, and the Caribbean.

What Are the Symptoms?

You usually start showing signs of leptospirosis within 2 weeks, though in some cases, symptoms may not show up for a month or not at all.

When the disease does hit, it hits fast. You’ll get a fever. It may spike to 104 F. Other typical symptoms include:

  • Headache
  • Muscle ache
  • Jaundice (yellowing of the skin and eyes)
  • Vomiting
  • Diarrhea
  • Skin rash

Many of these symptoms are similar to other diseases, including the flu and meningitis, so it’s important to get tested.

To check for leptospirosis, your doctor does a simple blood test and examines the blood for antibodies. These are organisms your body produces to fight the bacteria. If you have had the disease in your system before, the blood test may give a false positive (or show antibodies from the previous infection). So your doctor will likely do a second test about a week later to make sure the results are correct.

Your doctor could order a DNA test. It’s more precise, but is more expensive and takes longer, and in many areas of the world, it’s not available yet. The bacteria can also be detected if it grows in a blood, spinal fluid, or urine culture

How Do you Treat It?

Leptospirosis can be treated with antibiotics, including penicillin and doxycycline. Your doctor may also recommend ibuprofen for fever and muscle pain.

The disease should run its course in about a week.

But, you may have to go to the hospital if your infection is more severe. Symptoms may include kidney failure, meningitis, and lung problems. You may need to have antibiotics injected into your body, and in very serious cases, the infection could damage your organs.

Treatment in cases of complications can vary. For example, the disease can spread through your body (systemic inflammatory syndrome) and cause internal bleeding and inflame your pancreas or gallbladder. You or those around you might notice changes in your speech or behavior after the spread of this infection.

It also could inflame the heart muscle (myocarditis), leading to symptoms of heart failure including blockages and an irregular heartbeat (dysrhythmia). Your doctor will assess your other symptoms, overall health, health history, age, and other factors before deciding how to treat these complications.

How Can You Prevent It?

Avoid contaminated water. If you’re in a developing country, don’t drink the water unless you’re sure it’s clean. But because leptospirosis can enter through other body openings, it’s also a good idea to avoid swimming, waterskiing, sailing, or fishing in freshwater areas. Saltwater is generally safe.

Keep away from infected animals, especially wild rats. Rats and other rodents are the main carriers of the bacteria. Even in the Western world, 20% of wild rats may have it. Be careful if you have to handle wild rats or come in contact with their habitats.

In the developed world, farm animals are usually vaccinated, so there’s much less risk. If an animal is ill, avoid bites and body fluids. The disease can’t be passed through the air like a cold or the flu.

Be aware of your surroundings, especially when you travel. In countries with poor sanitation, leptospirosis is more common and may be hard to avoid. So, recognize the symptoms and seek help if you become ill.

Use disinfectant. Bleach, Lysol, acid solutions, and iodine are deadly to the bacteria. Keep them on hand to clean up.

Can Pets Get It?

All animals can get leptospirosis. Though it used to be rare in pets, it has shown up more often in the past few years, especially in dogs. (Leptospirosis is rare in cats.) Leptospirosis in dogs happens the same way it does in humans: through contact with the urine of infected animals, which can get into the water or soil and survive for weeks or months.

Your pet might not show any symptoms. Many of the symptoms of leptospirosis are very similar to other diseases, such as:

  • Fever
  • Belly pain, vomiting, diarrhea
  • Weakness
  • Pain 
  • Stiffness

The only way to know for sure if they have it is to ask your vet to do a test. And of course, if your pet is infected, they can pass it on to you. There is a leptospirosis vaccine available for dogs. Veterinarians recommend that any dog that goes outside at all -- even just to go to the bathroom -- be vaccinated against leptospirosis.