Bacillary dysentery See shigellosis

backpacks The popularity of carrying books in a backpack is almost universal in American schools, but overloading the packs can be harmful. Some studies have shown that as many as half of all teenagers suffer from back pain, which may be caused by the improper use of backpacks. While many factors may cause back pain, such as increased level of competition in sports, poor posture while sitting, and long periods of inactivity, far too many children are also carrying backpacks that exceed 15 percent of the child's body weight. Therefore, a 60-pound child should carry no more than nine pounds of books on the back.

Backpacks can be a helpful tool if they are used properly, since they can help children stay organized while toting their books and papers from home to school and back again. Compared to shoulder bags or purses, backpacks are better because the strongest muscles in the body, the back and the abdominal muscles, support the weight of the pack. Because the weight is evenly distributed across the child's body, shoulder and neck injuries are less common than if the child carried a briefcase.

When a backpack is too heavy, the child arches the back or leans the head and body forward to compensate for the weight of the bag. This stresses the muscles in the neck and back, increasing the risk of injury. Using only one strap, as many youngsters do, affects the spine's natural shock absorption abilities.

Most doctors and physical therapists recommend that children carry no more than 10 percent to 15 percent of their body weight in their packs.

Girls and younger children may be especially at risk for backpack-related injuries because they are smaller and may carry loads that are heavier in proportion to their body weight.

A backpack is too heavy if the child has to struggle to get a backpack on or off, has back pain, has to lean forward to carry a pack, or has numbness or weakness in arms or legs.

The safest backpack has two wide, padded straps that go over the shoulders, a padded waist or chest belt to distribute weight more evenly across the body, multiple compartments to distribute the weight of the load, and is not wider than the child's body. Backpacks with a metal frame are a good choice, but many lockers will not accommodate a pack that large. No matter how well designed the backpack, children need to keep the backpack loads reasonable.

Newest backpacks have wheels and allow students to roll, rather than carry, books and other materials.

A child should be encouraged to visit a locker or desk often throughout the day instead of carrying the entire day's worth of books in a backpack. Children should not carry unnecessary items such as laptops, CD players, and video games. if a child does have to carry something heavy in the pack, it should be placed closer to the back of the pack, next to the body.

As with any heavy weight, a child should bend at the knees and grab the pack with both hands when lifting it to his shoulders. Another way to prevent back injury is to strengthen the stabilizing muscles in the lower back and abdomen. Weight training and yoga can help strengthen the core muscles.


in children under the age of 24 months, bac-teremia accounts for about 10 percent of all cases of fever over 101.3°F. If a child this age runs a fever without localized signs, a blood test is usually taken.

bacteria Neither plants nor animals, bacteria are microbes whose nuclei are not enclosed in thin tissue like plants or animals. some bacteria feed on other organisms, some make their own food (as plants do), and some bacteria do both. some need air to survive and others exist without air (anaerobic). Some move by themselves, and others cannot move at all. Bacteria also come in a variety of shapes, colors, sizes, and ways of living. some of the more serious types of bacterial infections include gonorrhea, meningitis, whooping cough, pneumonia, and tuberculosis. Bacteria are of incredible importance because of their extreme flexibility, capacity for rapid growth and reproduction, and their ancient age—the oldest known fossils are those of bacteria-like organisms that lived nearly three-and-a-half billion years ago.

it is important to remember that not all bacteria are harmful; most are helpful, such as those that break down dead plant and animal matter in the soil. some (like the actinomycetes) produce antibiotics such as streptomycin and nocardicin. plants cannot grow without nitrogen, and bacteria help nitrogen to form in the soil. Bacteria are also used to make cheese out of milk, and leather out of animal hide. Grazing animals use bacteria in their stomachs to digest grass.

Bacteria can be found in the air, the water, food, and everyday objects. since few of these are harmful, humans are seldom bothered by them.


Unfortunately, bacteria are beginning to become resistant to many of the antibiotics doctors use to treat the infections. A 1996 World Health Organization report found that drug-resistant strains of microbes causing malaria, tuberculosis, pneumonia, cholera, and diarrhea are on the rise. Strong new types of microbes in the United States cause up to 60 percent of hospital-acquired infections, the report adds.

The problem occurs when antibiotics are prescribed when they are not needed, or when patients do not take the full course of medication, allowing a few microbes to survive.

bacterial endocarditis An infection of the lining of the heart that may occur in any infant or child, whether or not there is any heart disease present. Bacterial endocarditis does not occur very often, but when it does, it can cause serious heart damage, so it is important to prevent this infection if possible.


Bacterial endocarditis is caused by bacteria that enter the blood, lodging inside the heart where they multiply and cause infection. A normal heart has a smooth lining that is hard for bacteria to attach to, but children with congenital heart disease may have a roughened area on the heart lining caused by pressure from an abnormal opening or a leaky valve. Even after surgery, roughened areas may remain as a result of scar tissue formation or patches used to redirect blood flow. These rough areas make perfect places for bacteria to build up and multiply.

Bacteria that cause this problem may get into the blood during dental procedures, tonsillectomy, or adenoidectomy, examination of the respiratory passageways with a rigid bronchoscope, or during certain types of surgery on the respiratory passageways, the gastrointestinal tract, or the urinary tract.

Any infant or child who has congenital heart disease that has not yet been repaired can develop bacterial endocarditis. Some children who have already had a heart defect repaired may also need to take precautions against bacterial endocarditis for the rest of their lives, while others may no longer need to observe these precautions. Heart problems that put children at risk for developing bacterial endocarditis include mitral valve prolapse, having artificial heart valves, a previous history of endocarditis, complex cyanotic congenital heart disease due to insufficient oxygen in the blood, and surgically constructed systemic pulmonary shunts. Other heart problems linked to endocarditis may include acquired valve dysfunction, such as is due to rheumatic heart disease or collagen vascular disease, or an enlarged heart muscle that causes impeded blood flow.

Your Heart and Nutrition

Your Heart and Nutrition


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