BK Virus Infection

Medically reviewed by Drugs.com. Last updated on Apr 6, 2025.

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What is a BK virus infection?

A BK virus (BKV) infection is a common viral infection that usually does not cause problems. The BK virus may be spread if you have contact with infected blood or body fluids, such as saliva. It can spread from one person to another during an organ transplant or from a mother to her baby during delivery.

What increases my risk for problems from a BKV infection?

• Older age
• Kidney surgery or injury
• Organ transplant
• Health conditions that weaken your immune system, such as AIDS or diabetes

What are the signs and symptoms of a BKV infection?

Most people do not have any signs or symptoms of a BKV infection. The virus normally remains inactive in your body when your immune system is strong. If your immune system becomes weak, the virus may become active and you may have any of the following:

• Blurred vision or vision changes
• Brown or red urine
• Pain when you urinate
• Difficulty urinating, or needing to urinate more than is normal for you
• Cough, colds, or trouble breathing
• Fever, muscle pain, or weakness
• Seizures

How is a BKV infection diagnosed?

• Blood and urine tests will show if you are infected with the BK virus. They can also check your kidney function and get information about your overall health.
• A kidney biopsy is a procedure to remove a small amount of tissue from your kidney to see if you are infected with the BK virus.

How is a BKV infection treated?

A BKV infection may go away on its own without treatment. If you take antirejection medicine, your healthcare provider may change or decrease your dose. You may also need any of the following:

• Medicines may be used to decrease pain, help your immune system, or kill the BK virus.
• Bladder irrigation is done to rinse your bladder and help you pass urine.
• Hyperhydration helps flush your bladder. You may be given liquids to drink or through an IV.

What can I do to prevent the spread of germs?

• Wash your hands often. Wash your hands several times each day. Wash after you use the bathroom, change a child's diaper, and before you prepare or eat food. Use soap and water every time. Rub your soapy hands together, lacing your fingers. Wash the front and back of your hands, and in between your fingers. Use the fingers of one hand to scrub under the fingernails of the other hand. Wash for at least 20 seconds. Rinse with warm, running water for several seconds. Then dry your hands with a clean towel or paper towel. Use hand sanitizer that contains alcohol if soap and water are not available. Do not touch your eyes, nose, or mouth without washing your hands first.
• Cover a sneeze or cough. Use a tissue that covers your mouth and nose. Throw the tissue away in a trash can right away. Use the bend of your arm if a tissue is not available. Wash your hands well with soap and water or use a hand sanitizer.
• Clean surfaces often. Clean doorknobs, countertops, cell phones, and other surfaces that are touched often. Use a disinfecting wipe, a single-use sponge, or a cloth you can wash and reuse. Use disinfecting cleaners if you do not have wipes. You can create a disinfecting cleaner by mixing 1 part bleach with 10 parts water.
• Ask about vaccines you may need. No vaccine is available for BKV, but vaccines can help prevent some diseases caused by viruses and bacteria. Vaccines can help protect your immune system. Get the influenza (flu) vaccine as soon as recommended each year. The flu vaccine is usually available starting in September or October. Flu viruses change, so it is important to get a flu vaccine every year. Get the pneumonia vaccine if recommended. This vaccine is usually recommended every 5 years. Your provider will tell you when to get this vaccine, if needed. Your healthcare provider can tell you other vaccines you should get and when to get them.

When should I seek immediate care?

• Your symptoms get worse and do not go away even after you take pain medicine.
• You have severe pain when you urinate.
• Your urine has blood in it.

When should I call my doctor?

• You have a fever, or feel weak and achy.
• You have trouble urinating.
• You have questions about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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