Infectious Disease

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus. It can affect your liver's ability to function.

You're most likely to get hepatitis A from contaminated food or water or from close contact with a person or object that's infected.

Symptoms of Hepatitis A

Hepatitis A signs and symptoms can include:

• Fatigue
• Sudden nausea and vomiting
• Abdominal pain or discomfort, especially on the upper right side beneath your lower ribs (by your liver)
• Clay-colored bowel movements
• Loss of appetite
• Low-grade fever
• Dark urine
• Joint pain
• Yellowing of the skin and the whites of your eyes (jaundice)
• Intense itching

When to See a Doctor

Ask your doctor about receiving the hepatitis A vaccine if:

• You've traveled out of the country recently, particularly to Mexico or South or Central America, or to areas with poor sanitation
• A restaurant where you recently ate reports a hepatitis A outbreak
• Someone close to you, such as a roommate or caregiver, is diagnosed with hepatitis A
• You recently had sexual contact with someone who has hepatitis A

Hepatitis B is a liver infection caused by the hepatitis B virus. Some people with hepatitis B are sick for only a few weeks, but for others the disease progresses to a serious, lifelong illness known as chronic hepatitis B.

Symptoms of Hepatitis B

Symptoms of acute hepatitis B can include:

• Fever
• Fatigue
• Loss of appetite
• Nausea
• Vomiting
• Abdominal pain
• Dark urine
• Clay-colored bowel movements
• Joint pain
• Jaundice (yellow color in the skin or the eyes)

You can spread hepatitis B without having symptoms.

When to See a Doctor

If you are concerned that you might have been exposed to the hepatitis B virus, call your provider immediately.

Infection with the hepatitis B virus can be prevented if you get the hepatitis B vaccine and/or a shot called “HBIG” (hepatitis B immune globulin) as soon as possible after exposure to the virus, ideally within 24 hours.

Hepatitis C is an infection caused by a virus that attacks and inflames the liver. It can cause liver swelling (inflammation) and can sometimes lead to severe liver damage including cirrhosis and liver failure.

The virus is spread through contact with the blood of an infected person, most commonly through the sharing of needles/syringes or sexual contact.

Learn about hepatitis C treatment available here

Symptoms of hepatitis C

Many people newly infected with the hepatitis C virus don't have symptom and don't know they are infected. For people who develop symptoms, they usually happen 2–12 weeks after exposure to the hepatitis C virus and can include:

• Yellow skin or eyes
• Lack of appetite
• Upset stomach
• Vomiting
• Stomach pain
• Fever
• Dark urine
• Light-colored stool
• Joint pain
• Feeling tired

Most people with chronic hepatitis C don't have any specific symptoms other than fatigue and depression. Many will eventually develop chronic liver disease, which can range from mild to severe and include cirrhosis and liver cancer.

Staphylococcus aureus is a type of germ that about 30% of people carry in their noses. Most of the time, staph does not cause any harm; however, sometimes staph causes infections. In healthcare settings, these staph infections can be serious or fatal, including:

• Bacteremia or sepsis when bacteria spread to the bloodstream.
• Pneumonia, which most often affects people with underlying lung disease including those on mechanical ventilators.
• Endocarditis (infection of the heart valves), which can lead to heart failure or stroke.
• Osteomyelitis (bone infection), which can be caused by staph bacteria traveling in the bloodstream or put there by direct contact such as following trauma (puncture wound of foot or intravenous (IV) drug abuse).

Who's at risk for staphylococcus aureus?

Anyone can develop a staph infection, although certain groups of people are at greater risk, including people with chronic conditions such as diabetes, cancer, vascular disease, eczema, lung disease, and people who inject drugs.

In healthcare facilities, the risk of more serious staph infection is higher because many patients have weakened immune systems or have undergone procedures. It is higher for patients in intensive care units (ICUs), patients who have undergone certain types of surgeries and patients with medical devices inserted in their bodies.

Tuberculosis (TB) is a potentially serious infectious disease that mainly affects your lungs. The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air via coughs and sneezes.

Symptoms of TB

The symptoms depend on where in your body the TB bacteria are growing. TB bacteria usually grow in the lungs, but can also affect the kidney, spine and brain.

Signs and symptoms of TB can include:

• A bad cough that lasts three weeks or longer
• Pain in the chest
• Coughing up blood or sputum
• Weakness or fatigue
• Weight loss
• No appetite
• Chills
• Fever
• Sweating at night

When to See a Doctor

See your doctor if you have a fever, a persistent cough, unexplained weight loss or drenching night sweats. Since these symptoms can also occur with other diseases, it's important to see a doctor and to let them find out if you have TB.

If you think you have been exposed to TB, get a TB test.

AIDS (acquired immunodeficiency syndrome) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). HIV damages your immune system and interferes with your body's ability to fight infection and disease.

HIV is a sexually transmitted infection (STI). It can also be spread by contact with infected blood or from mother to child during pregnancy, childbirth or breastfeeding.

Without medication, it typically takes 8 to 10 years before HIV turns into AIDS.

While there's no cure for HIV/AIDS, medications can dramatically slow the progression of the disease and reduce deaths.

Symptoms of HIV

The symptoms of HIV and AIDS vary, depending on the phase of infection. Symptoms typically begin with a flu-like illness within two to four weeks after the virus enters your body. The illness may last for a few weeks.

Other possible signs and symptoms include:

• Fever
• Headache
• Swollen lymph glands, mainly on the neck
• Muscle aches and joint pain
• Rash
• Sore throat
• Painful mouth sores
• Diarrhea
• Weight loss
• Cough
• Night sweats

When to See a Doctor

If you think you may have been infected with HIV or are at risk of contracting the virus, see a doctor as soon as possible.

Bone infections (known as osteomyelitis) can reach a bone by traveling through your bloodstream or spreading from nearby tissue. Infections can also begin in the bone itself if an injury exposes the bone to germs.

Smokers and people with chronic health conditions, such as diabetes or kidney failure, are more at risk of developing osteomyelitis.

Bone infections can be successfully treated. The dead areas of the bone are removed surgically, followed by strong intravenous antibiotics.

Symptoms of Bone Infections

Signs and symptoms of osteomyelitis include:

• Fever
• Swelling, warmth and redness over the area of the infection
• Pain in the area of the infection
• Fatigue

Sometimes there are no signs and symptoms, or they are hard to distinguish from other issues. This may be especially true for infants, older adults and people whose immune systems are compromised.

When to See a Doctor

See your doctor if you experience worsening bone pain along with fever.

If you're at risk of infection because of a medical condition or recent surgery or injury, see your doctor right away if you notice signs and symptoms of an infection.

Even with safety precautions, any surgery that causes a break in the skin can lead to a surgical site infection (SSI) on the part of the body where the surgery took place. If you have surgery, the chances of developing an SSI are about 1% to 3%.

Types of Surgical Site Infections

An SSI typically occurs within 30 days after surgery. The CDC describes three types of surgical site infections:

Superficial incisional SSI. This infection occurs just in the area of the skin where the incision was made.

Deep incisional SSI. This infection occurs beneath the incision area in muscle and the tissues surrounding the muscles.

Organ or space SSI. This type of infection can be in any area of the body other than skin, muscle, and surrounding tissue that was involved in the surgery. This includes a body organ or a space between organs.

Symptoms of Surgical Site Infections

• Soreness, pain, and irritation at the site
• A fever that spikes at about 100.3°F (38°C) or higher for more than 24 hours
• Drainage from the site that's cloudy, yellow, tinged with blood, or foul or sweet smelling

When to See a Doctor

If you think you have an SSI, you should contact your doctor right away.

Meningitis is an inflammation of the fluid and membranes (meninges) surrounding your brain and spinal cord.

Most cases of meningitis in the United States are caused by a viral infection, but other causes include bacterial, parasitic and fungal infections. Some cases of meningitis improve without treatment in a few weeks. Others can be life-threatening and require emergency antibiotic treatment.

Symptoms of Meningitis

Possible signs and symptoms in anyone older than the age of two include:

• Sudden high fever
• Stiff neck
• Severe headache
• Headache with nausea or vomiting
• Confusion or difficulty concentrating
• Seizures
• Sleepiness or difficulty waking
• Sensitivity to light
• Lack of appetite or thirst

Newborns and infants up to age two may show these signs:

• High fever
• Constant crying
• Excessive sleepiness or irritability
• Difficulty waking from sleep
• Inactivity or sluggishness
• Not waking to eat
• Poor feeding
• Vomiting
• A bulge in the soft spot on top of a baby's head (fontanel)
• Stiffness in the body and neck
• May be difficult to comfort, and may even cry harder when held

When to See a Doctor

Seek immediate medical care if you or someone in your family has meningitis signs or symptoms. Bacterial meningitis is serious and can be fatal within days without prompt antibiotic treatment.

It's also important to talk to your doctor if a family member or someone you live or work with has meningitis. You may need to take medications to prevent getting the infection.

Encephalitis is inflammation of the brain, most commonly caused by a viral infection. It's difficult to predict how encephalitis will affect each individual, so it's important to be diagnosed and start treatment quickly.

Symptoms

Most people with viral encephalitis have no symptoms, or mild flu-like symptoms, such as:

• Headache
• Fever
• Fatigue or weakness
• Aches in muscles or joints

Sometimes the signs and symptoms are more severe, and might include:

• Seizures
• Confusion, agitation or hallucinations
• Loss of consciousness (including coma)
• Loss of sensation or paralysis in certain areas of the face or body
• Muscle weakness
• Problems with speech or hearing

In infants and young children, signs and symptoms might also include:

• Nausea and vomiting
• Lack of appetite or not waking for a feeding
• Bulging in the soft spots of an infant's skull
• Irritability
• Body stiffness

When to See a Doctor

Get immediate care if you are experiencing any of the more-severe symptoms associated with encephalitis. If you have a severe headache, fever and altered consciousness, you should seek urgent care.

Infants and young children with any signs or symptoms of encephalitis should receive urgent care.

Abscesses can show up any place on your body. Most of them are caused by infections, and are full of pus, bacteria and debris.

If you have a weakened immune system, you can get certain abscesses more often because your body has a decreased ability to ward off infections.

Other risk factors for abscess include exposure to dirty environments, exposure to persons with certain types of skin infections, poor hygiene and poor circulation.

Antibiotics alone will not usually cure an abscess. An abscess typically must be opened and drained in order for it to improve. Sometimes draining occurs on its own, but generally it must be opened with the help of a warm compress or by a doctor in a procedure called incision and drainage (I&D).

When to See a Doctor

Call your doctor if any of the following occur with an abscess:

• You have a sore larger than a half-inch across.
• The sore continues to enlarge or becomes more painful.
• The sore is on or near your rectal or groin area.
• You develop a fever.
• You notice red streaks, which can mean the infection is spreading.

Go to the Emergency Department if any of these conditions occur with an abscess:

• Fever of 102°F or higher, especially if you have a chronic disease or are on steroids, chemotherapy, or dialysis
• A red streak that leads away from the sore or with tender lymph nodes (lumps) in an area anywhere between the abscess and your chest area
• Any facial abscess larger than a half-inch across

Malaria

You get malaria from a parasite, which is transmitted to you via bites from infected mosquitos.
If you contract malaria, you will feel very sick, with a high fever and shaking chills. It can be deadly.

If you will be traveling to tropical and subtropical locations where malaria is common, take steps to prevent mosquito bites by wearing protective clothing, using insect repellants and sleeping under treated mosquito nets.

Depending on the area you are visiting and your individual risk factors for infection, you may also want to take preventive medicine before, during and after your trip.
Visit our Travel Medicine clinic

Symptoms of Malaria

Malaria signs and symptoms typically begin within a few weeks after being bitten by an infected mosquito. However, some types of malaria parasites can lie dormant in your body for up to a year.

These are the signs and symptoms of a malaria infection:

• Fever
• Chills
• Headache
• Nausea and vomiting
• Muscle pain and fatigue
• Sweating
• Chest or abdominal pain
• Cough

When to See a Doctor

Talk to your doctor if you experience a fever while living in or after traveling to a high-risk malaria region. 

If you have severe symptoms, seek emergency medical attention.

Typhoid Fever

Typhoid fever is caused by Salmonella typhi bacteria, which you can get from contaminated food and water or close contact with an infected person.

Typhoid fever is rare in developed countries, but it is a risk when you travel in the developing world.

Vaccines are only partially effective against typhoid fever. Vaccines usually are reserved for those who may be exposed to the disease or who are traveling to areas where typhoid fever is common.

Symptoms of Typhoid Fever

Signs and symptoms are likely to develop gradually — often appearing one to three weeks after exposure to the disease.

Early illness symptoms include:

• Fever that starts low and increases daily, possibly reaching as high as 104.9 F
• Headache
• Weakness and fatigue
• Muscle aches
• Stomach pain
• Diarrhea or constipation
• Sweating
• Dry cough
• Loss of appetite and weight loss
• Rash
• Extremely swollen stomach

Without treatment, you may:

• Become delirious
• Lie motionless and exhausted with your eyes half-closed in what's known as the typhoid state
• Life-threatening complications can develop at this time

When to See a Doctor

If you have signs and symptoms of typhoid fever after you return home from a foreign country, consider seeing a doctor who focuses on international travel medicine or infectious diseases. A doctor who is familiar with these areas may be able to recognize and treat your illness more quickly.

Parasites

A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.

Skin and soft tissue infections can be caused by a variety of bacteria and other microorganisms that enter the skin through wounds, burns and irritated skin. People with neuropathy (numbness), peripheral vascular disease (circulation disorder) and diseases of the lymph system are more susceptible to skin and soft tissue infections.

The best known of these is MRSA, a bacteria commonly found on the skin that has become resistant to antibiotics. You're most likely to contract MRSA in healthcare settings or if you live in a communal setting (prisons, military barracks) or share common spaces, such as locker rooms.

A UTI can effect any part of your urinary system—your kidneys, ureters, bladder and urethra. It's caused when bacteria enters the urinary tract through the urethra and begins to multiply in the bladder.

The most common UTIs occur mainly in women and affect the bladder and urethra.

Bladder infections can be painful and annoying. Serious consequences can occur if a UTI spreads to your kidneys.

Symptoms

Urinary tract infections don't always cause signs and symptoms, but when they do they may include:

• A strong, persistent urge to urinate
• A burning sensation when urinating
• Passing frequent, small amounts of urine
• Urine that appears cloudy
• Urine that appears red, bright pink or cola-colored — a sign of blood in the urine
• Strong-smelling urine
• Pelvic pain, in women — especially in the center of the pelvis and around the area of the pubic bone

When to See a Doctor

Contact your doctor if you have signs and symptoms of a UTI.