Rickets is a disorder primarily caused by lack of vitamin D, calcium, or phosphate, which leads to softening and weakening of the bones. It is a bone problem that usually occurs in children. Rickets can make your child's bones hurt. The bones soften and can break easily.

Unintentional weight loss is a decrease in body weight that is not voluntary. In other words, you did not try to loss the weight by dieting or exercising. Any condition in which you lose your appetite for an extended period of time?a chronic illness like cancer, for example?can strip you of pounds.

Bronchitis is an acute inflammation of the air passages within the lungs. It occurs when the trachea (windpipe) and the large and small bronchi (airways) within the lungs become inflamed because of infection or other causes.

Constipation refers to a decrease in the frequency of bowel movements. For some people, it may mean difficulty in passing stools. A constipated stool is hard because it contains less water than normal.

Diphtheria is a bacterial infection that affects the tonsils, pharynx, larynx, nose, and skin . It produces a thick membrane which covers the area of inflammation. Children under 5 and adults over 60 years old are particularly at risk for contracting the infection.

Giardia is an infection of the small intestine caused by a protozoa. It is usually asymptomatic in humans but may produce abdominal cramps, diarrhea, and nausea. The species that infects humans and causes diarrhea is Giardia lamblia.

Gonorrhea is a sexually transmitted disease (STD). Gonorrhea is caused by Neisseria gonorrhoeae, a bacterium that can grow and multiply easily in the warm, moist areas of the reproductive tract, including the cervix (opening to the womb), uterus (womb), and fallopian tubes (egg canals) in women, and in the urethra (urine canal) in women and men.

HIV is a type of virus called a retrovirus. Like all viruses, it must invade the cells of other organisms to survive and reproduce. HIV multiplies in the human immune system's CD4+ T cells and kills vast numbers of the cells it infects. The result is disease symptoms.

Beriberi is a vitamin deficiency disease in which the body does not have enough thiamine (vitamin B1). Beriberi literally means "I can't, I can't" in Singhalese, which reflects the crippling effect it has on its victims.

Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.

Diabetes is a set of related diseases in which the body cannot regulate the amount of sugar (glucose) in the blood. Glucose in the blood gives you energy?the kind you need when you walk briskly, run for a bus, ride your bike, take an aerobics class, and perform your day-to-day chores.

Eating disorders involve extreme disturbances in eating behaviors?following rigid diets, gorging on food in secret, throwing up after meals, obsessively counting calories. But eating disorders are more complicated than just unhealthy dietary habits.

Kwashiorkor is the medical name for malnutrition. When the child is weaned, if the diet that replaces the milk is high in starches and carbohydrates, and deficient in protein (as is common in parts of the world where the bulk of the diet consists of starchy vegetables, or where famine has struck), the child may develop kwashiorkor.

Leprosy is a chronic infectious disease which attacks the skin, peripheral nerves and mucous membranes. Leprosy is an infectious disease that has been known since biblical times. It may be characterized by disfiguring skin sores, peripheral nerve damage

Obesity is considered a long-term complex disease. Many factors are involved in determining why some people are heavier than others and how much risk they have for developing other medical problems. Science continues to search for answers.

Infertility is defined as the failure to become pregnant after one year of unprotected intercourse. There are two types of infertility; Primary infertility, which is infertility without any previous pregnancy; and secondary infertility, when there has been a previous pregnancy.

Insomnia is the inability to get high-quality sleep. It can last a day or two, a month, or even months on end. Because different individuals need different amounts of sleep, insomnia is not defined by the number of hours you sleep or by how quickly you fall asleep.

Smallpox is a very serious infection which is caused by a virus named variola, which is a member of the poxvirus family. Smallpox has been a greatly feared disease because it was responsible for huge epidemics.

Syphilis is a sexually transmitted disease (STD) or sexually transmitted infection (STI) that, when left untreated, can progress to a late stage that causes serious health problems.

Typhoid fever is an acute illness associated with fever caused by the Salmonella typhi bacteria. It can also be caused by Salmonella paratyphi, a related bacterium that usually causes a less severe illness. The bacteria are deposited in water or food by a human carrier and are then spread to other people in the area.