YELLOW FEVER

DEFINITION

Yellow fever is a viral infection spread by a particular type of mosquito (Aedes spp). The infection is most common in areas of Africa and South America, affecting travelers to and residents of those areas.

In mild cases, yellow fever causes fever, headache, nausea and vomiting. But yellow fever can become more serious, causing heart, liver and kidney problems along with bleeding (hemorrhaging). Up to 50 percent of people with the more severe form of yellow fever die of the disease.

There's no specific treatment for yellow fever. But getting a yellow fever vaccine before traveling to an area in which the virus is known to exist can protect you from the disease.

SYMPTOMS

During the first three to six days after you've contracted yellow fever — the incubation period — you won't experience any signs or symptoms. After this, the infection enters an acute phase and then, in some cases, a toxic phase that can be life-threatening.

Acute phase

Once the infection enters the acute phase, you may experience signs and symptoms including:

Fever, Headache, Muscle aches, particularly in your back and kneesSensitivity to light, Nausea, vomiting or both Loss of appetite, Dizziness, Red eyes, face or tongue. These signs and symptoms usually improve and are gone within several days.

Toxic phase

Although signs and symptoms may disappear for a day or two following the acute phase, some people with acute yellow fever then enter a toxic phase. During the toxic phase, acute signs and symptoms return and more-severe and life-threatening ones also appear. These can include:

Yellowing of your skin and the whites of your eyes (jaundice), Abdominal pain and vomiting, sometimes of blood, Decreased urination, Bleeding from your nose, mouth and eyes, Slow heart rate (bradycardia), Liver and kidney failure, Brain dysfunction, including delirium, seizures and coma. The toxic phase of yellow fever can be fatal.

When to see a doctor

Before travel

Four weeks or more before your trip, make an appointment to see your doctor if you're traveling to an area in which yellow fever is known to occur so that you discuss whether you need the yellow fever vaccine.If you have less than four weeks to prepare, call your doctor anyway. Ideally, you'll be able to be vaccinated at least three to four weeks before traveling to an area where yellow fever occurs to give the vaccine time to work. Your doctor will help you determine whether you need vaccinations and can provide general guidance on protecting your health while abroad.

After travel

Seek emergency medical care if you've recently traveled to a region where yellow fever is known to occur and you develop signs or symptoms of the toxic phase of the disease.Call your doctor if you develop mild symptoms, after traveling to a region where yellow feveroccurs.

CAUSES

Yellow fever is caused by a virus that is spread by the Aedes aegypti mosquito. These mosquitoes thrive in and near human habitations where they breed in even the cleanest water. Most cases of yellow fever occur in sub-Saharan Africa including Nigeria and tropical South America.

Humans and monkeys are most commonly infected with the yellow fever virus. Mosquitoes transmit the virus back and forth between monkeys, humans or both.

When a mosquito bites a human or a monkey infected with yellow fever, the virus enters the mosquito's bloodstream and circulates before settling in the salivary glands. When the infected mosquito bites another monkey or human, the virus then enters the host's bloodstream, where it may cause illness.

Aedes aegypti

RISK FACTORS

You may be at risk of the disease if you travel to an area where mosquitoes continue to carry the yellow fever virus. These areas include sub-Saharan Africa and tropical South America.

Even if there aren't current reports of infected humans in these areas, it doesn't mean you're risk-free. It's possible that local populations have been vaccinated and are protected from the disease, or that cases of yellow fever just haven't been detected and officially reported.

If you're planning on traveling to these areas, you can protect yourself by getting a yellow fevervaccine at least several weeks before traveling.

Anyone can be infected with the yellow fever virus, but older adults are at greater risk of getting seriously ill.

COMPLICATIONS

Yellow fever results in death for 20 to 50 percent of those who develop severe disease. Complications during the toxic phase of a yellow fever infection include kidney and liver failure, jaundice, delirium, and coma.

People who survive the infection recover gradually over a period of several weeks to months, usually without significant organ damage. During this time a person may experience fatigue and jaundice. Other complications include secondary bacterial infections, such as pneumonia or blood infections.

PREPARING FOR YOUR APPOINTMENT

Call your doctor if you've recently returned from travel abroad and develop mild symptoms similar to those that occur with yellow fever. If your symptoms are severe, go to an emergency room or call 911 or your local emergency number.

Here's some information to help you get ready, and know what to expect from your doctor.

Information to gather in advance

Symptoms history; Write down any symptoms you've been experiencing and for how long. Recent exposure to possible sources of infection. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with mosquitoes.

medical histtory; Make a list of your key medical information, including other conditions for which you're being treated and any medications, vitamins or supplements you're taking. Your doctor will also need to know your vaccination history.

Questions to ask your doctor; Write down your questions in advance so that you can make the most of your time with your doctor.

The list below suggests questions to raise with your doctor about yellow fever. Don't hesitate to ask more questions during your appointment.

What's the most likely cause of my symptoms? Are there any other possible causes for my symptoms? What kinds of tests do I need? Are treatments available to help me recover? How long do you expect a full recovery will take? When can I return to work or school? Am I at risk of any long-term complications from yellow fever?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to talk about in-depth. Your doctor may ask:

What are your symptoms? When did you first begin experiencing symptoms? Have your symptoms seemed to be getting better or worse? Did your symptoms briefly get better and then come back? Have you recently traveled abroad? Where? Were you exposed to mosquitoes while traveling? Did you update your vaccinations before traveling? Are you being treated for any other medical conditions? Are you taking any medications?

TESTS AND DIAGNOSIS

Diagnosing yellow fever based on signs and symptoms can be difficult because early in its course, the infection can be easily confused with malaria, typhoid, dengue fever and other viral hemorrhagic fevers.

To diagnose your condition, your doctor will likely:

Ask questions about your medical and travel historyCollect a blood sample for testing

If you have yellow fever, your blood may reveal the virus itself. If not, blood tests also can detect antibodies and other substances specific to the virus.

TREATMENTS AND DRUGS

No antiviral medications have proved helpful in treating yellow fever. As a result, treatment consists primarily of supportive care in a hospital. This includes providing fluids and oxygen, maintaining adequate blood pressure, replacing blood loss, providing dialysis for kidney failure, and treating any other infections that develop. Some people receive transfusions of plasma to replace blood proteins that improve clotting.

If you have yellow fever, your doctor will likely recommend that you stay inside, away from mosquitoes, to avoid transmitting the disease to others. Once you've have yellow fever, you'll be immune to the disease for the rest of your life.

LIFESTYLE AND HOME REMEDIES

A safe and highly effective vaccine prevents yellow fever. Yellow fever is known to be present in sub-Saharan Africa and parts of South America. If you live in one of these areas, talk to your doctor about whether you need the yellow fever vaccine. If you plan to travel in these areas, talk with your doctor at least 10 days, but preferably three to four weeks, before your trip begins. Some countries require travelers to present a valid certificate of immunization upon entry.

A single dose of the yellow fever vaccine provides protection for at least 10 years. Side effects are usually mild, lasting five to 10 days, and may include headaches, low-grade fevers, muscle pain, fatigue and soreness at the site of injection. More-significant reactions — such as developing a syndrome similar to actual yellow fever, inflammation of the brain (encephalitis) or death — can occur, most often in infants and older adults. The vaccine is considered safest for those between the ages of 9 months and 60 years.

Talk to your doctor about whether the yellow fever vaccine is appropriate if your child is younger than 9 months, if you have a weakened immune system (immunocompromised), or if you're older than 60 years.

Mosquito protection

In addition to getting the vaccine, you can help protect yourself against yellow fever by protecting yourself against mosquitoes.

To reduce your exposure to mosquitoes:

Avoid unnecessary outdoor activity when mosquitoes are most active.Wear long-sleeved shirts and long pants when you go into mosquito-infested areas.Stay in air-conditioned or well-screened housing.If your accommodations don't have good window screens or air-conditioning, use bed nets. Nets that have been pre-treated with insecticide offer additional protection.

To ward off mosquitoes with repellent, use both of the following:

Non-skin repellen; Apply permethrin-containing mosquito repellent to your clothing, shoes, camping gears and bed netting. You can buy some articles of clothing and gear pre-treated with permethrin. Permethrin is not intended for use on your skin.

Skin repellent; Products with the active ingredients DEET, IR3535 or picaridin provide long-lasting skin protection. Choose the concentration based on the hours of protection you need. In general, higher concentrations last longer.

Keep in mind that chemical repellents can be toxic, and use only the amount needed for the time you'll be outdoors. Don't use DEET on the hands of young children or on infants under 2 months of age. Instead, cover your infant's stroller or playpen with mosquito netting when outside.

According to the Centers for Disease Control and Prevention, oil of lemon eucalyptus, a more natural product, offers the same protection as DEET when used in similar concentrations. But these products should not be used on children younger than age 3.

Oral Thrush Or Oral Candidiasis

DEFINITION

 Oral thrush — also called oral candidiasis (kan-dih-DIE-uh-sis) — is a condition in which the fungus Candida albicans accumulates on the lining of your mouth. Candida is a normal organism in your mouth, but sometimes it can overgrow and cause symptoms. Oral thrush causes creamy white lesions, usually on your tongue or inner cheeks. Sometimes oral thrush may spread to the roof of your mouth, your gums or tonsils, or the back of your throat. Although oral thrush can affect anyone, it's more likely to occur in babies, the elderly, and in people with suppressed immune systems or certain health conditions, or those who take certain medications. Oral thrush is a minor problem if you're healthy, but if you have a weakened immune system, symptoms of oral thrush may be more severe and difficult to control.

SYMPTOMS

 Initially, you may not even notice symptoms of oral thrush. Depending on the underlying cause, signs and symptoms may develop slowly or suddenly, and they may persist for days, weeks or months. Signs and symptoms may include: Creamy white lesions on your tongue, inner cheeks, and sometimes on the roof of your mouth, gums and tonsils Slightly raised lesions with a cottage cheese-like appearance Redness or soreness that may be severe enough to cause difficulty eating or swallowing Slight bleeding if the lesions are rubbed or scraped Cracking and redness at the corners of your mouth (especially in denture wearers) A cottony feeling in your mouth Loss of taste In severe cases, the lesions may spread downward into your esophagus — the long, muscular tube stretching from the back of your mouth to your stomach (Candida esophagitis). If this occurs, you may experience difficulty swallowing or feel as if food is getting stuck in your throat. Infants and breast-feeding mothers In addition to the distinctive white mouth lesions, infants may have trouble feeding or be fussy and irritable. They can pass the infection to their mothers during breast-feeding. The infection may then pass back and forth between the mother's breasts and the baby's mouth. Women whose breasts are infected with candida may experience these signs and symptoms: Unusually red, sensitive, cracked or itchy nipples Shiny or flaky skin on the darker, circular area around the nipple (areola) Unusual pain during nursing or painful nipples between feedings Stabbing pains deep within the breast When to see a doctor If you or your child develops painful white lesions inside the mouth, see your doctor or dentist. If thrush develops in older children or teenagers, seek medical care. An underlying medical condition or certain treatments may be the cause.

 CAUSES

 Normally, your immune system works to repel harmful invading organisms, such as viruses, bacteria and fungi, while maintaining a balance between "good" and "bad" microbes that normally inhabit your body. But sometimes these protective mechanisms fail, increasing the number of candida fungi and allowing an oral thrush infection to take hold. Oral thrush and other candida infections can occur when your immune system is weakened by disease or by drugs such as prednisone, or when antibiotics disturb the natural balance of microorganisms in your body. These diseases and conditions may make you more susceptible to oral thrush infection: HIV/AIDS. Human immunodeficiency virus (HIV) — the virus that causes AIDS — damages or destroys cells of your immune system, making you more susceptible to opportunistic infections that your body would normally resist. Repeated bouts of oral thrush, along with other symptoms, may be early indications of an immune deficiency, such as HIV infection. Cancer. If you have cancer, your immune system is likely to be weakened from the disease and from treatments such as chemotherapy and radiation. Both the disease and treatments can increase your risk of candida infections such as oral thrush. Diabetes mellitus. If you have untreated diabetes or the disease isn't well-controlled, your saliva may contain large amounts of sugar, which encourages the growth of candida. Vaginal yeast infections. Vaginal yeast infections are caused by the same fungus that causes oral thrush. Although a yeast infection isn't dangerous, if you're pregnant you can pass the fungus to your baby during delivery. As a result, your newborn may develop oral thrush.

RISK FACTORS

 Anyone can develop oral thrush, but the infection is more common in certain people. Risk factors include: Being an infant or elderly Having a weakened immune system Wearing dentures Having other health conditions, such as diabetes Taking certain medications, such as antibiotics or oral or inhaled corticosteroids Undergoing chemotherapy or radiation treatment for cancer Having conditions that cause dry mouth

COMPLICATIONS

 Oral thrush is seldom a problem for healthy children and adults, although the infection may return even after it's been treated. For people with lowered immunity, such as from HIV or cancer, however, thrush can be more serious. Untreated oral thrush can lead to more-serious systemic candida infections. If you have a suppressed immune system: Thrush is more likely to spread to other parts of your body, such as your digestive tract, lungs, liver and heart valves You may have especially severe symptoms in your mouth or esophagus, which can make eating painful and difficult The infection can spread to the intestines, making it difficult to receive adequate nutrition

PREPARING FOR YOUR APPOINTMENT

 You're likely to start by seeing your family doctor or pediatrician. However, if you have an underlying condition that's contributing to the problem, you may then be referred to a specialist for treatment. Here's some information to help you get ready for your appointment. What you can do Make a list of any symptoms, including any that may seem unrelated to the reason for the appointment. Make a list of all medications, vitamins or other supplements you're taking, including the dosages. Also, let your doctor know if you've recently used antibiotics or if you take oral or inhaled corticosteroids such as those used to treat asthma. Make a list of questions to ask your doctor to help you make the most of your appointment. For oral thrush, some basic questions to ask your doctor include: What caused this condition? Do I need any additional tests? Do these tests require any preparation? What treatments are available, and which do you recommend? Do these treatments have any side effects? I have other medical problems, so how can I manage them together? Are there any dietary restrictions that I need to follow? Is there a generic alternative to the medicine you're prescribing? How can I prevent this from happening again? Do I need to be tested for other diseases associated with thrush? Don't hesitate to ask any other questions that occur to you. What to expect from your doctor Your doctor is likely to ask you a number of questions, such as: When did you begin experiencing symptoms? Have you recently taken antibiotics for an infection? Do you have asthma? If so, do you use a steroid inhaler? Do you have any chronic health conditions? Do you have any other new symptoms of illness?

TESTS AND DIAGNOSIS

 Oral thrush can usually be diagnosed simply by looking at the lesions, but sometimes a small sample is examined under a microscope to confirm the diagnosis. In older children or teens who have no identified risk factors, an underlying medical condition may be the cause of oral thrush. If your doctor suspects that's the case, he or she will likely perform a physical exam and recommend certain blood tests to help find the source of the problem. If thrush is in your esophagus Thrush that extends into the esophagus can be serious. To help diagnose this condition, your doctor may ask you to have one or both of these tests: Throat culture. In this procedure, the back of your throat is swabbed with sterile cotton. Then the tissue sample is cultured on a special medium to help determine which bacteria or fungi, if any, are causing your symptoms. Endoscopic exam. In this procedure, your doctor examines your esophagus, stomach and upper part of your small intestine (duodenum) using a lighted, flexible tube with a camera on the tip (endoscope).

TREATMENTS AND DRUGS

 The goal of any oral thrush treatment is to stop the rapid spread of the fungus, but the best approach may depend on your age, your overall health and the cause of the infection. Healthy adults and children. Your doctor may recommend antifungal medication. This comes in several forms, including lozenges, tablets, or a liquid that you swish in your mouth and then swallow. Infants and nursing mothers. If you're breast-feeding and your infant has oral thrush, you and your baby could pass the infection back and forth. Your doctor may prescribe a mild antifungal medication for your baby and an antifungal cream for your breasts. Ask your doctor about the best way to clean your breast nipples, bottle nipples, pacifiers and any detachable parts of a breast pump if you use one. Adults with weakened immune systems. Most often your doctor will recommend antifungal medication. But Candida albicans can become resistant to many antifungal medications, especially in people with late-stage HIV infection. So a drug called amphotericin B may be used, but only when other drugs aren't effective, as it can cause serious side effects.

LIFESTYLE AND HOME REMEDIES

 These measures may help reduce your risk of developing candida infections: Rinse your mouth. If you have to use a corticosteroid inhaler, be sure to rinse your mouth with water or brush your teeth after taking your medication. Brush your teeth at least twice a day and floss daily or as often as your dentist recommends. Clean your dentures. Clean your dentures daily. Ask your dentist for the best way to clean your type of dentures. See your dentist regularly, especially if you have diabetes or wear dentures. Ask your dentist how often you need to be seen. Watch what you eat. Try limiting the amount of sugar- and yeast-containing foods you eat. These may encourage the growth of candida. Maintain good blood sugar control if you have diabetes. Well-controlled blood sugar can reduce the amount of sugar in your saliva, discouraging the growth of candida. Treat any vaginal yeast infections that develop during pregnancy as soon as possible.