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.