Dear Doctor: West Nile virus is active again in southern California. What happens when you are infected? Is there a vaccine?

Dear Reader: There’s been a surge of West Nile virus in people this summer, with southern California, Nevada and central Arizona recording the highest number of cases of the mosquito-borne illness. According to statistics released by the Centers for Disease Control and Prevention at the beginning of September, 326 confirmed cases of West Nile virus disease in humans have been reported in 35 states. Of those, close to two-thirds resulted in neuro-invasive diseases such as meningitis or encephalitis.

West Nile virus has been identified as the leading cause of mosquito-borne disease in the continental United States. It’s caused by the bite of an infected mosquito and is seen in birds, humans, horses and other mammals. Mosquitoes acquire the virus when they feed on an infected bird. Since many species of birds migrate great distances, and since mosquitoes inhabit virtually every corner of the world, West Nile virus has spread rapidly. The virus isn’t transmitted between humans or other mammals. Although it can be acquired via a blood transfusion or an organ transplant from an infected donor, the U.S. blood supply is tested for the virus and is thus considered safe.

West Nile cases typically spike during late spring to late autumn. That’s when warm temperatures and wet weather create ideal conditions for mosquitoes to breed and spread. Scientists say that our rapidly warming world is also playing a role in the global spread of the disease. First identified in Africa in 1937, the disease made its first appearance in the U.S. in New York City in 1999. The virus now is seen across a majority of the continental U.S. As rising temperatures extend the breeding season of mosquitoes, scientists warn that cases of West Nile will continue to rise.

The good news is that about 80% of people who become infected with the virus will have no symptoms at all. About 20% will have symptoms that are mild and not life-threatening. These include flu-like symptoms such as fever accompanied by headache, body aches and nausea. Additional symptoms of mild illness may include rash, joint pain and stiffness, as well as fatigue, which can persist for weeks. A fraction of the population -- about one in every 150 people infected with the virus -- will develop potentially serious illnesses, including neurological conditions such as encephalitis, which is inflammation of the brain, or meningitis, in which the membranes surrounding the brain and spinal cord become inflamed.

Symptoms of severe illness include high fever, headache, muscle weakness, stiffness in the neck, changes to cognition, tremors, numbness and paralysis. If infection with West Nile virus is suspected, seek medical help. Although vaccines are available for horses, there is not yet a vaccine for humans.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I just started my first post-college job, which I love. Nevertheless, I’ve been feeling really stressed and anxious. My boyfriend says stress can affect your health. What can I do?

Dear Reader: First, congratulations on this major milestone in your life. As for finding it stressful, please know that you’re not alone. Starting a new job is often overwhelming, and with good reason. Virtually everything -- the physical environment, the people, the social culture and the work itself -- is unfamiliar.

Your boyfriend is correct that, over time, stress can result in adverse health effects. Acute stress, which we experience in response to a single event or situation, can make your heart race or send your blood pressure soaring. Some people experience headaches, stomach pain, sweating, nausea and bowel problems. Chronic stress, which is long-term exposure to the cascade of hormonal changes that set off the stress response, can lead to depression, sleep disorders, cardiovascular problems, weight gain, systemic inflammation, a weakened immune system and an increased risk of a range of diseases.

You can learn to manage the stress of this transition. First, recognize that sources of stress can be mental, emotional or physical. By taking a detailed mental inventory of your workdays, you can identify the specific situations that result in distress. On the physical side of things, which is your working conditions, take the necessary steps to be safe and comfortable. Depending on your occupation, this applies to lighting, temperature, ventilation, the ergonomics of the workstation or familiarity with safety procedures. When it comes to mental and emotional stressors, which pretty much everyone has on the job, focus on coping techniques. Deep-breathing exercises and mindfulness techniques have been shown to reduce stress significantly. You can learn about these techniques by reading books or taking a class. If that doesn’t help, seeing a therapist can help.

The next step is to pay attention. Identify the specific triggers that set off your stress response. Maybe it’s a tight deadline, a public presentation, someone’s management style or even interacting with a challenging co-worker. Once you know your danger zones, you can prepare with your preferred coping technique. Afterward, use the technique again to get centered. As with everything, the key here is practice and consistency.

In small amounts, stress is no big deal. But chronic stress can take a steep physical and emotional toll. The sooner you learn to identify and manage it, the better off you’ll be.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: We thought our 4-year-old son had caught a cold at daycare because he had a slight fever, but then he got these weird red spots on his feet. Our doctor said it’s foot and mouth disease. Is it dangerous?

Dear Reader: Your son is among the many children who contract hand, foot and mouth disease every year. Often referred to as HFMD, it’s a contagious viral infection that’s common in children under the age of 5, particularly during the warmer summer months.

Symptoms include fever and those red spots (which are a rash) that appeared on the soles of his feet. Additional symptoms of HFMD often include a sore throat; painful blisters or lesions on the tongue, gums and on the insides of the cheeks; loss of appetite; and a general feeling of discomfort or malaise. The red rash may also appear on the palms of the hands, and sometimes on the buttocks. Although the rash doesn’t itch, it can develop into fluid-filled blisters.

The disease is caused by a variety of enteroviruses, most commonly by one known as coxsackievirus A16. It’s spread through contact with certain bodily secretions from an infected person. These include the aerosolized spray from a cough or a sneeze, saliva, nasal secretions, throat discharge or stool. The fluid contained in the blisters is also infectious.

Considering how babies and toddlers explore the world around them with their mouths and their hands, it’s not surprising that HFMD is common among the younger set. It’s often seen in daycare settings, where it’s easily passed among the group. Since several different strains of enteroviruses cause the infection, it’s possible to get HFMD more than once. However, the good news is that, over time, kids can develop an immunity. Although HFMD is most common in children, adolescents and adults can contract the virus as well.

In the majority of cases, HFMD is not dangerous. The fever lasts a few days, and the sore throat may last a day or two longer. Most patients recover within seven to 10 days without any specialized treatment. In addition to feeling crummy as their immune systems mount a defense against the virus, the tongue and mouth sores can make it painful for patients to swallow. That makes hydration a priority. Offer frequent sips of water and other beverages throughout the day, but steer clear of citrus juices, which can irritate the mouth sores.

It’s rare but possible for a certain form of coxsackievirus to cause someone with HFMD to develop viral meningitis, an infection of the brain and spinal cord. Another rare complication is encephalitis, a life-threatening inflammation of the brain. That’s alarming, so let’s re-emphasize that those complications are rare.

Parents of kids with HFMD should alert their daycare provider so they can do a thorough cleaning of the facilities. Meanwhile, be vigilant about family hand hygiene, disinfect all common areas and keep sick children at home until fever and all sores have completely resolved.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)