W. David Colby IV MSc MD FRCPC


Severe Acute Respiratory Syndrome (SARS)

Severe acute respiratory syndrome (SARS) is a respiratory illness caused by a type of virus called a coronavirus. SARS produces symptoms similar to pneumonia and can be spread when someone with SARS coughs, sneezes, laughs, or speaks. The main symptoms are a fever, a dry cough, shortness of breath, or difficulty…

Symptoms of Lyme Disease

The first symptom of Lyme disease in most people is an expanding red skin rash (called erythema migrans or an EM rash). In about a third of people, the rash looks like a bull’s-eye, with a pale center area surrounded by a bright red rim. The rash is often accompanied by flu-like symptoms, including: Fatigue (the most…

Antigen Tests for Giardiasis

For a giardia antigen test, a stool sample or fluid from the upper part of the intestines (duodenal fluid) is tested in the lab for the presence of antigens from Giardia lamblia. This test is often done at the same time as a stool analysis.

Lyme Disease: Role of Blood Tests

If you were exposed to ticks and you get an expanding, circular rash (erythema migrans), your doctor may treat you for Lyme disease without doing a blood test. Blood tests done in the first few weeks may not show Lyme disease even when you have the illness. This is because the body’s immune system responds slowly to the…

Colorado Tick Fever

Colorado tick fever is an infectious viral disease that can be passed to humans by ticks. Colorado tick fever occurs in the mountain region of the western United States. Symptoms usually start within 14 days (average of 3 to 6 days) of the tick bite. Symptoms of Colorado tick fever include: Fever and chills. Headache…