H. flu meningitis is a serious disease that can result in permanent damage to a child. More than two-thirds of all bacterial meningitis victims are children younger than five years old. Until 1992 most of them were infected with Haemophilus influenzas type b, usually shortened to H. flu or “Hib.” Don’t be confused by the name—this disease has nothing to do with influenza, which is a virus. Now Hib meningitis has virtually disappeared in children younger than five thanks to the effective vaccine.

Haemophilus influenzae, a small rod-shaped bacterium that has several different strains, causes H. flu meningitis. Each strain has a different type of capsule surrounding the bacterium. Type b was the most common cause of meningitis in Read the rest of this entry »

Hepatitis C virus (HCV), identified in 1988, used to be known as non-A, non-B hepatitis. It was the third kind of viral hepatitis named and recognized.

Tests to detect actual infection are not yet available, so the actual number of hepatitis C infections is unknown, but it is believed to be the most common form of viral hepatitis in the United States. The CDC estimates that 150,000 Americans are infected each year. In Canada, doctors reported 1,050 hepatitis C cases in 1992. Long-term liver damage from Read the rest of this entry »

Hepatitis B is the most common preventable infectious disease in the United States. It’s estimated that there are 200,000 to 300,000 cases each year, of which only about 15,000 are reported. About 1 million Americans are chronic carriers—they are infected and infectious for the rest of their lives. Almost 6,000 people in the United States die each Read the rest of this entry »

Hepatitis A is the most common type of hepatitis. In 1994, 22,000 people were reported to have hepatitis A, while hepatitis B, the next most common, had 11,000 reported cases in the United States. Hundreds of thousands more cases go unreported, however. It was the first kind of hepatitis named and recognized, hence the name hepatitis A. The virus Read the rest of this entry »

Hepatitis describes any inflammation of your liver. It’s generally caused by a virus, but certain drugs or alcoholism can damage your liver and give you hepatitis.

So far, scientists have identified five specific viruses that cause hepatitis, called simply A, B, C, D, and E. Delta or D virus is always a co-infection with hepatitis B, and hepatitis E does not occur in North America. The viruses are completely unrelated to each other, but their actions are similar in that they attack and damage only the liver, causing inflammation and cell death.

When your liver isn’t working properly, it cannot do its jobs, one of which is to excrete a waste substance called bilirubin. The bilirubin builds up in the blood, causing a yellow tinge to the skin and eyes, called jaundice, and other symptoms. With hepatitis A, the liver damage is temporary. As you develop antibodies, you get rid of the virus, and your liver returns to normal with no long-term effects. With hepatitis B or C, however, long-term complications can result.

Rarely and for unknown reasons, hepatitis quickly develops into a condition called fulminant hepatitis, in which the liver Read the rest of this entry »

Hantavirus Pulmonary Syndrome

In May 1993, a devastating and mysterious illness suddenly appeared in the Four Corners region where New Mexico meets Arizona, Colorado, and Utah. Healthy young adults developed high fevers, chills, muscle aches, and coughs—and then collapsed. The first victims all lived on or near the Navajo Indian Reservation.

Their lungs filled up with fluid, causing asphyxiation and death. One died while dancing, one while buying groceries, and another while on the way to his girlfriend’s funeral, who had been one of the first victims.

Doctors didn’t know where the disease came from, how it worked, or how it chose its victims. They named it adult Read the rest of this entry »

Head Lice

For some reason the nurses at the Children’s Hospital of Philadelphia were extremely concerned when head lice showed up on a child. I would get desperate phone calls from nursing and housekeeping whenever they found a louse nit on a child.

Before the 1950s, head lice was common and children’s heads were regularly inspected for lice. By the time most of today’s parents were growing up, head lice was rare. Parents, school nurses, and doctors stopped checking regularly for lice. As a result, in the 1970s, head lice reappeared all over North America in school-age children.

The cause is pediculus humanus capitis, the scientific name for the head louse. Unlike bacteria and viruses, which are microbial species, the head louse is a wingless insect visible to the human eye that lives only on the human scalp, where it feeds by sucking blood. It is small, gray or brown, and only three to four mm long—about the size of a sesame Read the rest of this entry »

Mouth Disease

When I first heard of hand, foot, and mouth disease, I thought it had something to do with cows. Actually, this is a long and serious-sounding name for a mild viral illness that usually affects only young children. It’s called hand, foot, and mouth disease because these are the places where the rash appears.

Hand, foot, and mouth disease is caused by a virus known as coxsackie A 16. This virus belongs to the enterovirus family, a common type of virus that infects only humans and lives in the digestive tract. So far, scientists have discovered 30 different kinds of coxsackie virus and placed them into two groups, A and B. Sometimes other coxsackie Read the rest of this entry »