Are you having back pain with any of the following?

  • Severe pain, weakness or tingling in your leg(s).
  • Difficulty stopping urination or loss of control of bladder or bowels.
  • Unexplained fever, nausea or vomiting.
  • A history of cancer or unexplained weight loss.

We understand that you are experiencing one or more of the health issues that might be impacting your back pain.

We recommend that you discuss these health issues with your doctor before proceeding with this program.

Once you are cleared by your doctor to do this program, we hope it helps you find relief from your back pain.

Provider photo for Jonathan Volk

Jonathan Volk, MD

Infectious Diseases

Welcome to My Doctor Online, a web site that my colleagues and I developed to make it easier for you to take care of your healthcare needs. On this site you will find answers to many of your questions about my clinical practice. Also included are several online features that will allow you to e-mail me, check your laboratory results and refill prescriptions. I hope you find its content informative and useful.

My Offices

San Francisco Medical Center
Appt/Advice: 415-833-2200

See all office information »

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West Nile virus (WNV) is a health condition you should be aware of if you spend a lot of time outdoors. The most common way to be infected is through a mosquito bite. Anyone can be infected, but people over 50 are at highest risk for developing WNV infection-related health problems or severe West Nile disease. There is no specific treatment for West Nile virus.

Most people infected with WNV have no symptoms, but about 1 in 5 (20 percent) develop a flu-like illness with fevers and body aches known as "West Nile fever." Symptoms are mild in the majority of patients, we recommend using some of the same measures which are useful in treating the general flu: rest, drink plenty of fluids, and take ibuprofen or acetaminophen for fever and body aches. Your symptoms should clear up in a few days.

More serious symptoms of WNV consist of severe headache, stiff neck, high fever, mental confusion or disorientation, and muscle weakness or paralysis. Persons with a more severe form of infection with WNV may have some or all of those symptoms. Typically less than one percent of people who contract WNV get severe disease. Certain individuals who are older than 50 or have a compromised immune system are at higher risk to develop the more severe form of WNV. All those who have the symptoms of the more severe form or are at risk to develop the more severe form should seek prompt medical attention.

You can prevent WNV the same way you avoid mosquito bites: Wear protective clothing, use insect repellent (with DEET), and remove standing water where mosquitoes breed or lay eggs.


Most people with WNV (about 80 percent) do not experience any symptoms.  

Those who do develop symptoms have a condition known as West Nile fever. Symptoms can begin anywhere from 2 to 15 days after infection and are similar to those for the flu:  

  • Headache
  • Fever
  • Body aches
  • Sore throat
  • Back pain
  • Lack of appetite
  • Upset stomach or diarrhea
  • A rash on the chest, arms, and body

On average, these symptoms last 3 to 6 days. Occasionally, they last longer, up to several weeks in some people.

In very rare cases (less than one percent), WNV can spread to involve the brain and cause life-threatening health conditions such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membrane surrounding the brain or spinal cord). The following symptoms indicate that WNV has become more dangerous and you should seek immediate medical help:

  • Severe headache
  • High fever
  • Muscle weakness or paralysis
  • Stiff neck
  • Confusion
  • Blurred vision
  • Tremors or convulsions
  • Loss of consciousness

People aged 50 or older or those who have a weakened immune system are much more likely to develop this more severe WNV disease. In particular, patients undergoing treatment for certain types of cancer or those who are recipients of an organ transplantation are at high risk to develop the more severe form of WNV disease. Also, if you are pregnant or have a young child with symptoms of WNV, it is important to consult with your doctor to determine the need for further evaluation.


WNV infection usually occurs when you are bitten by an infected mosquito. WNV is found throughout the United States and the world in places where mosquitoes live and breed, like lakes and ponds or other standing water. You are also more likely to be infected with WNV if you spend a lot of time outdoors, especially when mosquitoes are more abundant in the summer and fall. 

You are at increased risk of developing West Nile fever or severe West Nile virus disease if you:

  • Are age 50 or older
  • Have a weakened immune system (for example, if you are undergoing treatment for certain types of cancer or if you are the recipient of an organ transplantation)
  • Have a chronic illness

Rare cases of WNV infection have been reported to have resulted from a blood transfusion, donated organ from an infected donor, and from an infected mother to her infant via breast milk. These are examples of some extremely uncommon ways of acquiring WNV infection.

Although pets like cats and dogs can get infected by WNV, such infections are typically mild. There are no known cases of transmission of WNV infection from an infected pet to a human.


Depending on your symptoms, the season, and the activity of WNV in your area, your health care provider will assess your risk for WNV infection. 

To help us confirm a WNV diagnosis, we may need to order tests including:

  • Blood tests. These check for the presence of WNV antibodies that your body has created to fight this infection. 
  • Spinal tap. This test may be necessary, especially when symptoms suggest involvement of the brain in the infection. 

Additional testing, like an MRI of the brain, may be necessary, based on the nature and severity of symptoms.


The best way to avoid a WNV infection is to prevent getting bitten by mosquitoes:

  • Use mosquito repellant that contains DEET.
  • Wear long sleeves and pants when outdoors.
  • Stay indoors at dusk and dawn, when mosquitoes are most active.
  • Place screens on your windows and doors.
  • Drain or remove any pools or puddles of standing water around your house – even small amounts that might collect in trash can lids, bird baths, or plant containers – where mosquitoes can lay eggs.

Do not handle dead birds with your bare hands; contact your local health department for instructions on handling and disposing of dead birds you may come across.

Be sure to take similar precautions when participating in recreational activities like camping, hunting, or fishing.

If you have WNV and develop a high fever, stiff neck, and/or severe headache, seek help immediately. These are signs that the infection may be severe WNV disease, which we should treat right away to decrease related health complications.


Because WNV is a viral infection, antibiotic medications are not effective for treatment. You may not even know you had WNV because the virus has come and gone without producing any symptoms.

If you are one of the 20 percent of people with WNV who develop West Nile fever, we recommend home care:

  • Get plenty of rest.
  • Drink lots of fluids.
  • Take ibuprofen or acetaminophen to reduce fever and body aches. 
  • Take a lukewarm bath to reduce fever.

Continue treatment until you feel better, usually about 3 to 6 days. If at any time during treatment you feel a severe headache, high fever, stiff neck, and/or any type of confusion, you should contact us immediately for further care.

If you have a weak immune system (for example, if you are undergoing treatment for certain types of cancer or if you are a recipient of an organ transplantation), you should contact us immediately even if your symptoms are mild.

In rare instances when symptoms indicate you could develop severe complications, we may recommend hospitalization. We will monitor your symptoms and address any changes in your condition as needed.

Whatever level of care you require, we will work with you to address your symptoms and try to decrease any complications you may have.

Your Care with Me

If you are having symptoms that concern you, your first contact will typically be with your personal physician, who will evaluate your health and symptoms.

If specialty care is needed, your personal physician will facilitate the process of scheduling an appointment in my department. If appropriate, she or he might call me or one of my colleagues while you are in the office so we can all discuss your care together. If we decide you need an appointment with me after that discussion, we can often schedule it the same day or soon thereafter.

During your office visit, we will discuss your medical and family history and I will perform a physical exam. I will explain the findings of your exam and answer any questions or concerns you may have. We will discuss treatment options and develop a treatment plan that is right for you.

If you need to talk with me after your visit or procedure, please call my office. You can also e-mail me with nonurgent issues from this website whenever it is convenient for you.

For general medical advice, our Appointment and Advice line is available 24 hours per day, 7 days per week.

If you have urgent concerns or issues while my office is closed, or need general medical advice, you can call the Appointment and Advice line. You will be connected with a nurse who can give you immediate advice.

If you are experiencing a serious problem or an emergency, call 911 or go to the nearest Emergency Room when the clinic is not open.

Coordinating Your Care

Having all of our Kaiser Permanente departments located together or nearby, including pharmacy, laboratory, radiology, and health education, makes getting your care easier for you.

Another major benefit is our comprehensive electronic medical record system, which allows all of the doctors and clinicians involved in your care to stay connected on your health status and collaborate with each other as appropriate.

When every member of the health care team is aware of all aspects of your condition, care is safer and more effective.

If you come to an office visit
  • At the beginning of your visit, you will receive information about when you are due for your next test, screening, or immunization. We can discuss and schedule any preventive tests that you need. 
  • At the end of your visit, you may receive a document called the “After Visit Summary” that will summarize the issues we discussed during your visit. You can refer to it if you forget what we discussed, or if you just want to recheck your vital signs and weight. You can also view it online under Past Visits.
  • To help you prepare for your visit, please see additional details under Office Visit. 
If I prescribe medications

We will work together to monitor and assess how your medications are working and make adjustments over time. Prescriptions can be filled at any Kaiser Permanente pharmacy. Just let me know which pharmacy works best for you, and I will send the prescription electronically in advance of your arrival at the pharmacy.

If refills are needed in the future, you can:

  • Order them online or by phone. Order future refills from my home page or by phone using the pharmacy refill number on your prescription label.
  • Have them delivered to you by mail at no extra cost. Or you can pick up your medications at the pharmacy. If no refills remain when you place your order, the pharmacy will contact me regarding your prescription.
If lab testing or imaging is needed

For lab tests, I will use our electronic medical record system to send the requisition to the Kaiser Permanente laboratory of your choice. For imaging procedures, we will schedule an appointment with the Radiology department. When the results are ready, I will contact you with your results by letter, secure e-mail message, or phone. In addition, you can view most of your laboratory results online, along with any comments that I have attached to explain them.

If I refer you to another specialty colleague

If we decide together that your condition would also benefit from the care of other types of specialists, our staff will help arrange the appointment(s) with one or more of my specialty colleagues.

If surgery or a procedure is a treatment option

I will recommend that you review educational information and tools to help you prepare for your procedure or surgery. The information will often help you decide whether surgery is right for you. If you decide to have a surgery or procedure, the information will provide details about how to prepare and what to expect.

If we proceed with surgery, I will have my Surgery Scheduler contact you to determine a surgery date and provide you with additional instructions regarding your procedure. Once your surgery is scheduled, a medical colleague of mine will contact you to conduct a preoperative medical evaluation that will assure that you are properly prepared for your surgery.

Convenient Resources for You

As your specialist, I have a goal to provide high-quality care and to offer you choices that make your health care convenient. I recommend that you become familiar with the many resources we offer so that you can choose the services that work best for you.

My Doctor Online is available at any time that is most convenient for you. From my home page you can:

Manage your care securely
  • View and compose secure e-mail messages.
  • Manage your prescriptions.
  • View your past visits and test results.
  • View your preventive services to see whether you are due for a routine screening or updated immunization.
Learn more about your condition
  • Read about causes, symptoms, treatments, and procedures.
  • Find interactive health tools, videos, and podcasts to help you manage your condition.
  • View programs to help you decide on or prepare for a surgery or procedure.
Stay healthy
  • Locate health education classes and support groups offered at every medical center.
  • Explore interactive programs, videos, and podcasts that focus on helping you stay healthy.
  • View your Preventive Services to see whether you are due for a routine screening or updated immunization.

If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following: (1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.

This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.

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