West Nile virus (WNV) is an infectious disease. It is most often spread by the bite of an infected mosquito. Most people have no symptoms, while some may develop mild symptoms. But WNV can sometimes cause serious symptoms if the virus enters your brain.

WNV usually spreads to people through the bite of an infected mosquito. However, in rare cases, it can spread from person-to-person. This can happen through an organ transplant or blood transfusion. If you are preganant you can spread WNV to your fetus during pregnancy or delivery. And after delivery, it can spread to the baby during breastfeeding.

Anyone could be bitten by an infected mosquito and get WNV. But certain people are at higher risk for more serious illness they get a WNV infection. They include people who:

• Are over age 60
• Have certain medical conditions, such as cancer, diabetes, high blood pressure, or kidney disease
• Had an organ transplant

Symptoms can be mild to severe. But most people have no symptoms or mild symptoms.

Mild symptoms of WNV can include:

• Fever
• Headache
• Body aches
• Vomiting
• Diarrhea
• Skin rash

These symptoms usually go away on their own within a few days to several weeks. But some people will have weakness or fatigue that lasts for weeks or months.

Although rare, If West Nile virus enters your brain, it can be life-threatening. It may cause inflammation of the brain (encephalitis) or inflammation of the tissue that surrounds the brain and spinal cord (meningitis).

Serious symptoms of WNV can include:

• High fever
• Headache
• Neck stiffness
• Numbness
• Coma
• Muscle weakness
• Vision loss

To find out if you have WNV, your health care provider:

• Will do a physical exam
• Will take your medical history, including asking about your symptoms
• May order blood tests

There are no specific vaccines or treatments for human WNV disease. But rest, fluids, and over-the-counter pain medicines may relieve some symptoms. You may need to be hospitalized if you have serious symptoms.

There are no vaccines or medicines to prevent WNV. The best way to avoid WNV is to help prevent mosquito bites:

• Wear insect repellent with DEET or another U.S. Environmental Protection Agency (EPA)-registered insect repellent. Make sure to follow the instructions for using the repellent.
• Wear long-sleeved shirts and pants if you're outside.
• Get rid of mosquito breeding sites by emptying standing water from flowerpots, buckets, or barrels.
• Stay indoors between dusk and dawn, when mosquitoes are most active.
• Use screens on windows to keep mosquitoes out.

Centers for Disease Control and Prevention (CDC)

Anatomy is the science that studies the structure of the body. On this page, you'll find links to descriptions and pictures of the human body's parts and organ systems from head to toe.

Tumors are abnormal growths in your body. They can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain.

Tumors are made up of extra cells. Normally, cells grow and divide to form new cells as your body needs them. When cells grow old, they die, and new cells take their place. Sometimes, this process goes wrong. New cells form when your body does not need them, and old cells do not die when they should. These extra cells can divide without stopping and may form a tumor.

Treatment often involves surgery. Benign tumors usually don't grow back.

NIH: National Cancer Institute

A biopsy is a procedure that removes cells or tissue from your body. A doctor called a pathologist looks at the cells or tissue under a microscope to check for damage or disease. The pathologist may also do other tests on it.

Biopsies can be done on all parts of the body. In most cases, a biopsy is the only test that can tell for sure if a suspicious area is cancer. But biopsies are performed for many other reasons too.

There are different types of biopsies. A needle biopsy removes tissue with a needle passed through your skin to the site of the problem. Other kinds of biopsies may require surgery.

The bladder is a hollow organ in your lower abdomen that stores urine. Bladder cancer occurs in the lining of the bladder. It is the sixth most common type of cancer in the United States.

Symptoms include:

• Blood in your urine
• A frequent urge to urinate
• Pain when you urinate
• Low back pain

Risk factors for developing bladder cancer include smoking and exposure to certain chemicals in the workplace. People with a family history of bladder cancer or who are older, White, or male have a higher risk.

Treatments for bladder cancer include surgery, radiation therapy, chemotherapy, and biologic therapy. Biologic therapy boosts your body's own ability to fight cancer.

NIH: National Cancer Institute