W. David Colby IV MSc MD FRCPC


Deer Tick

Source: Public Health Image Library (PHIL). Michael L. Levin, PhD. Available online: http://phil.cdc.gov. Deer ticks are one of two types of ticks in the United States that carry Lyme disease bacteria.

Misdiagnosis of Lyme Disease

Misdiagnosis of Lyme disease is common. The bacteria that cause the illness are hard to detect with current lab tests. People often test positive for Lyme disease when in fact they have a different bacterial illness. People may test positive because they were infected with the Lyme disease bacteria at some point during…

Relapsing Fever

Relapsing fever is an infectious disease that can be passed to humans by ticks. Relapsing fever is most common in the western United States. Symptoms usually start 3 to 11 days (average 6 days) after the tick bite. They may last for several days, go away, and then return (relapse) several days later. Symptoms of…

Severe Acute Respiratory Syndrome (SARS)

What is SARS? Severe acute respiratory syndrome (SARS) is a respiratory illness that first infected people in parts of Asia, North America, and Europe in late 2002 and early 2003. SARS is caused by a type of coronavirus, which can cause mild to moderate upper respiratory illness, such as the common cold. This virus is…

Neisseria Meningitidis

Meningitis caused by Neisseria meningitidis is sometimes referred to as meningococcal disease. Some people have Neisseria meningitidis in their throats without getting sick. But they can pass it to another person, who may get sick. Neisseria meningitidis causes meningitis in about 25 out of 100 people who get the…