Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by a strain of staph bacteria that's become resistant to the antibiotics commonly used to treat ordinary staph infections.
Most MRSA infections occur in people who've been in hospitals or other health care settings, such as nursing homes and dialysis centers. When it occurs in these settings, it's known as health care-associated MRSA (HA-MRSA). HA-MRSA infections typically are associated with invasive procedures or devices, such as surgeries, intravenous tubing or artificial joints.
Another type of MRSA infection has occurred in the wider community — among healthy people. This form, community-associated MRSA (CA-MRSA), often begins as a painful skin boil. It's spread by skin-to-skin contact. At-risk populations include groups such as high school wrestlers, child care workers and people who live in crowded conditions.
Staph skin infections, including MRSA, generally start as small red bumps that resemble pimples, boils or spider bites. These can quickly turn into deep, painful abscesses that require surgical draining. Sometimes the bacteria remain confined to the skin. But they can also burrow deep into the body, causing potentially life-threatening infections in bones, joints, surgical wounds, the bloodstream, heart valves and lungs.
Different varieties of Staphylococcus aureus bacteria, commonly called "staph," exist. Staph bacteria are normally found on the skin or in the nose of about one-third of the population. The bacteria are generally harmless unless they enter the body through a cut or other wound, and even then they usually cause only minor skin problems in healthy people.
According to the Centers for Disease Control and Prevention, less than 2 percent of the population carries the type of staph bacteria known as MRSA.
Throughout history, millions of people have died of diseases such as bubonic plague or the Black Death, which is caused by Yersinia pestis bacteria, and smallpox, which is caused by the variola virus. In recent times, viral infections have been responsible for two major pandemics: the 1918-1919 “Spanish flu” epidemic that killed 20-40 million people, and the ongoing HIV/AIDS epidemic that killed an estimated 1.5 million people worldwide in 2013 alone.Bacterial and viral infections have many things in common. Both types of infections are caused by microbes -- bacteria and viruses, respectively -- and spread by things such as:
Microbes can also cause:
Most importantly, bacterial and viral infections, can cause:
A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.Viruses spread in many ways; viruses in plants are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; viruses in animals can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal–oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. The range of host cells that a virus can infect is called its "host range". This can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many
Bacterial and viral infections have many things in common. Both types of infections are caused by microbes -- bacteria and viruses, respectively -- and spread by things such as:
Sweating and body odor are facts of life for most people. Heavy perspiration and body odor can happen when you exercise, when you're too warm, or when you're nervous, anxious or under stress.
Your body has two main types of sweat glands, and they produce two very different types of sweat. Both types are odorless, but the type of sweat produced in your armpits and groin smells bad when it combines with bacteria found normally on your skin.
Unusual changes in sweating — either excessive perspiration (hyperhidrosis) or little or no perspiration (anhidrosis) — can be cause for concern. Likewise, changes in body odor may be a sign of a medical problem.
For normal sweating and body odor, however, lifestyle and home treatments can effectively manage your symptoms.
Some people naturally sweat more or less than other people. Body odor also can vary from person to person. But you should see a doctor if:
Your skin has two main types of sweat glands: eccrine glands and apocrine glands. Eccrine glands occur over most of your body and open directly onto the surface of the skin. Apocrine glands develop in areas abundant in hair follicles, such as your armpits and groin, and they empty into the hair follicle just before it opens onto the skin surface.
When your body temperature rises, your eccrine glands secrete fluid onto the surface of your skin, where it cools your body as it evaporates. This fluid is composed mainly of water and salt.
Apocrine glands, on the other hand, produce a milky fluid that most commonly is secreted when you're under emotional stress. This fluid is odorless until it combines with bacteria found normally on your skin.
Like any allergy, mold allergy symptoms are triggered by an overly sensitive immune system response. When you inhale tiny, airborne mold spores, your body recognizes them as foreign invaders and develops allergy-causing antibodies to fight them.
After the exposure has passed, you still produce antibodies that "remember" this invader, so that any later contact with the mold causes your immune system to react. This reaction triggers the release of substances such as histamine, which cause itchy, watery eyes, runny nose, sneezing and other mold allergy symptoms.
Molds are very common both inside and outside. There are many types, but only certain kinds of mold cause allergies. Being allergic to one type of mold doesn't necessarily mean you'll be allergic to another. Some of the most common molds that cause allergies include alternaria, aspergillus, cladosporium and penicillium.
A number of factors can make you more likely to develop a mold allergy, or worsen your existing mold allergy symptoms, including:
Although a mold allergy is the most common problem caused by exposure to mold, mold can cause illness without an allergic reaction. Mold can also cause infections or irritant and toxic reactions. Infections caused by mold can lead to a variety of problems from flu-like symptoms to skin infections and even pneumonia.
An irritant reaction is caused when substances from molds called volatile organic compounds irritate the mucous membranes in the body. Symptoms of an irritant reaction are similar to an allergy and include eye irritation, runny nose, cough, hoarseness, headache and skin irritation.
Herpes is a very common infection. It is caused by two different but closely related viruses. The viruses are herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Both are easy to catch. They remain in the body for life and can produce symptoms that come and go.
Both forms of herpes can infect the oral area, the genital area, or both. When the infection is on or near the mouth, it is called oral herpes. Oral herpes is caused most often by HSV-1. When a herpes infection is on or near the sex organs, it is called genital herpes. Genital herpes is caused most often by HSV-2. More than half of American adults have oral herpes. And about 1 out of 6 American adults have genital herpes. Millions of people do not know they have herpes because they never had, or noticed, the herpes symptoms.
STDs are very common. But we can protect ourselves and each other from STDs like herpes. Learning more about herpes is an important first step.
Influenza is a viral infection that attacks your respiratory system — your nose, throat and lungs. Influenza, commonly called the flu, is not the same as the stomach "flu" viruses that cause diarrhea and vomiting.
Influenza and its complications can be deadly. People at higher risk of developing flu complications include:
Initially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly. And although a cold can be a nuisance, you usually feel much worse with the flu.
Common signs and symptoms of the flu include:
Flu viruses travel through the air in droplets when someone with the infection coughs, sneezes or talks. You can inhale the droplets directly, or you can pick up the germs from an object — such as a telephone or computer keyboard — and then transfer them to your eyes, nose or mouth.
People with the virus are likely contagious from the day before symptoms first appear until five to 10 days after symptoms begin. Children and people with weakened immune systems may be contagious for a slightly longer time.
Ringworm of the body is a fungal infection that develops on the top layer of your skin. It's characterized by a red circular rash with clearer skin in the middle. It may or may not itch. Ringworm gets its name because of its appearance. There is no actual worm involved.
Also called tinea corporis, ringworm of the body is closely related to athlete's foot (tinea pedis), jock itch (tinea cruris) and ringworm of the scalp (tinea capitis). Ringworm often spreads by direct skin-to-skin contact with an infected person or animal.
Antifungal medications are used to treat ringworm. Mild ringworm often responds to antifungal products that you apply to your skin. For more-severe infections, you may need to take antifungal pills for several weeks.
Ringworm typically begins as a flat scaly area on the skin, which may be red and itchy. This patch develops a slightly raised border that expands outward — forming a roughly circular ring. The contours of the ring may be quite irregular, resembling the wavy outline of a snake or a worm.he interior of the ring may be clear, scaly or marked with a scattering of red bumps. In some people, several rings develop at the same time and may overlap.
Ringworm is a contagious fungal infection caused by mold-like parasites that live on the cells in the outer layer of your skin. It can be spread in the following ways: