Sick

Dr. Raphael Stricker explains the connection between tick bites and Lyme disease, the symptoms that follow and treatments.

The measles virus has been around for thousands of years and is one of the most contagious diseases known to man. Dr. Roberto Cattaneo explains how easily it spreads and how outbreaks have been responsible for the deaths of millions of people.

The human immune system is a complex machine that sometimes stops fighting diseases and starts fighting you. Dr. Ali A. Duarte-Garcia shares how genetic and environmental factors may contribute to lupus.

Rabies has been scaring populations for thousands of years, but it's scary for more reasons than just a painful bite. Once the virus is inside us, it damages our mind, and it can happen fast or lay dormant for years before fatally attacking.

Malaria is one of the oldest diseases in human history and has even been attributed to aiding the fall of the Roman Empire. Dr. Karine le Roch explains why we haven't been able to stop the disease after fighting it for so long.

Leprosy bacteria is notorious for moving at a snail's pace, and Cressida Madigan explains what happens when it finally takes over the body.

Narcolepsy is more than falling asleep at seemingly random times. It causes hallucinations, insomnia, sleep paralysis and can be triggered by moments of joy, and the key to understanding it came from studying man's best friend.

For some, a peanut or a bite of shrimp can cause the body's immune system to wildly overreact, and the results may be deadly. Dr. Tina Sindher explains what's happening in the body for it to confuse nuts or shellfish with a true threat.

Human papillomavirus, or HPV, is known to give its host warts, but it can also lead to a deadly form of cancer. Dr. Barbara Moscicki explains why it's important for boys, as well as girls, to get vaccinated.

As if climbing a mountain wasn't hard enough already, forcing the body to acclimate to high altitudes too quickly can not only stop someone from reaching the summit, it can have dire consequences.