Summer means the arrival of certain illnesses and infections caused by bacteria, viruses and bugs that thrive in the warm, moist environment. Although the risk of catching these diseases is low, there are some precautions to take to stay healthy.
For more information on all the diseases, visit the U.S. Centers for Disease Control and Prevention at www.cdc.gov.
West Nile virus
What it is: A viral infection that first showed up in the United States 10 years ago and infected thousands each summer but has dropped off dramatically in recent years.
How it spreads: When a mosquito feeds on a bird infected with West Nile, the mosquito can carry the virus and infect a person through a bite. It is not transmitted from person to person.
Symptoms: Most people who are infected never develop symptoms. About 20 percent will develop headache, fever, body aches or rash. In very rare cases, the virus can lead to encephalitis (inflammation in the brain). Last year, 32 people in the United States died of West Nile virus.
Treatment: Doctors can treat the symptoms, but there is no cure. Most patients recover on their own.
Prevention: Spray insect repellent with DEET on exposed skin. Avoid being outdoors at dusk, when mosquitoes are most active. Remove all standing water from flower pots and bird baths.
Incidence: 720 confirmed cases in the United States last year.
What it is: A viral infection.
How it spreads: Dengue is transmitted by infected mosquitoes, not person to person. Dengue is the most common cause of fever in U.S. travelers to the Caribbean, central and South America and Asia. Upon their return, sickened U.S. travelers can infect domestic mosquitoes, who then spread it to other people.
Symptoms: Dengue typically causes mild illness or none at all. Symptoms can include fever, headache, severe joint pain, eye pain, rash and vomiting. Rarely, severe cases can lead to dengue hemorrhagic fever, which can be fatal.
Treatment: There is no specific drug to treat dengue illness, but the symptoms usually can be treated.
Prevention: As with West Nile, the best prevention is avoiding mosquito bites. Researchers at St. Louis University are conducting a human clinical trial of an experimental dengue vaccine. E-mail email@example.com or call 314-977-6333.
Incidence: The most common mosquito-borne virus, dengue infects more than 100 million people worldwide each year, mainly in tropical regions. There were no reports of cases acquired in the United States before 1980. Since then, a few cases have been reported along the Texas-Mexico border. Last month, the CDC confirmed 28 cases of dengue in Key West. Other recent outbreaks have been linked to American relief workers returning from Haiti.
What it is: A bacterial infection.
How it spreads: The disease is transmitted to humans by infected blacklegged ticks who in turn were infected by small rodents. It is not spread from human to human.
Symptoms: Fever, headache, fatigue, chills, swollen lymph nodes and a bulls-eye shaped rash in about 75 percent of cases. If untreated, the infection can produce symptoms ranging from facial paralysis, neck stiffness, dizziness and arthritis. Up to 5 percent of people who are untreated will develop neurological symptoms including pain, numbness and tingling in the extremities, and problems with memory and concentration.
Treatment : If the infection is caught early, a three-week course of antibiotics can usually stop its spread to joints and the nervous system.
Prevention: Tuck shirts into pants and pants into socks. Use insect repellent with DEET on exposed skin and permethrin on clothes (available at stores that sell outdoor equipment). Perform tick checks of the whole body, and remove any ticks with sharp tweezers. It is rare to contract Lyme disease if the tick has been on your body for fewer than 24 hours.
Incidence:—Most reported Lyme disease cases come from New England and upper Midwestern states. All states reported 28,921 confirmed and 6,277 probable cases of Lyme disease to the CDC in 2008, a 5 percent increase over 2007.
BATS, RACCOONS and SKUNKS
What it is: A viral disease that infects mammals.
How it spreads: Rabies is transmitted through the bites of wild, rabid animals.
Incidence: The majority of rabies cases reported to the CDC occur in wildlife, although most wild animals are not rabid. Last year in St. Louis County, Mo., 590 bats were tested; 23 had rabies. Domestic pets account for 7 percent of animal rabies cases. Human cases are extremely rare, with one or two a year nationwide. The death of a Texas County man in 2008 was the first in Missouri since 1959.
Symptoms: -- The virus infects the central nervous system and is fatal if not treated early. Early symptoms include fever, headache and weakness. Anxiety, confusion, paralysis and hallucinations can develop.
Treatment: If you are bitten by a wild animal, wash the area with soap and water and seek treatment immediately. Prophylactic shots can prevent rabies infection.
Prevention: Make sure your pets' rabies vaccinations are up to date. If you find a live or dead bat in your home, do not attempt to capture it. Call your county's health department, which will come collect the bat so it can be tested for disease.
What it is: An infection of the blood around the spinal cord and brain. Viral meningitis is generally less severe and tends to resolve on its own.
How it spreads: Bacterial meningitis is contagious in close contact among people through the exchange of saliva or respiratory secretions, although it is not as easily transmitted as the cold or flu and is not spread through the air.
Who it affects: Teenagers at sleep-away camp and college students living in dorms are at increased risk for meningococcal disease.
Symptoms: Common symptoms include fever, headache and stiff neck that may be accompanied by nausea, vomiting, sensitivity to light or an altered mental state. Rare but serious cases can result in the loss of limbs, deafness, seizures or brain damage.
Treatment: Early diagnosis is important to prevent severe illness and the spread of the disease. Meningococcal infections can be treated with antibiotics such as penicillin.
Prevention: A vaccine for bacterial meningitis protects about 90 percent of people who get it. The CDC recommends the vaccine for everyone ages 11 to 18.
Incidence: 1,000 to 2,600 Americans get meningococcal disease every year. About one in 10 cases is fatal.
What it is: A group of bacterial strains found in the intestines that are mostly harmless. Some strains can cause diarrhea and intestinal illnesses.
How it spreads: E. coli is spread through contact with water or food contaminated with animal feces. Raw milk, undercooked meat, swimming pools and bodies of water can all contain the bacteria.
Symptoms: Stomach cramps, diarrhea and vomiting.
Treatment: The symptoms can be treated with hydration. Antibiotics are generally not recommended. Most infections resolve within a week. Rarely, severe infections can lead to kidney damage and death.
Prevention: Wash hands with soap and water after using the bathroom or changing diapers. Avoid swallowing pool or lake water. Cook meat and wash fruits and vegetables thoroughly.
Incidence: There are an estimated 70,000 E. coli infections each year in the United States. Many people who are infected don't seek medical care or aren't tested for E. coli.