Diseases, Viruses and Illnesses

Chickenpox (varicella) is a viral illness most common in young children. When adults get it, they can become very sick.

COVID-19 is a respiratory illness caused by the SARS-CoV-2 virus. It was first identified in late 2019 and declared a pandemic by the World Health Organization on March 11, 2020. Find the latest on COVID-19 Disease and Infection.

Hand, foot and mouth disease is a virus most common in infants and young children. Infections occur more frequently in the summer months.

Hand, foot and mouth disease fact sheet [PDF].

Although listed here, head lice is NOT a disease. Head lice are a common nuisance and can spread whenever there is close to head-to-head contact, particularly among children in childcare programs, schools and recreational groups. Head lice poses no health risk. Learn how to identify and treat head lice.

Head lice fact sheet and FAQ [PDF]

Viral hepatitis is a group of liver diseases that can be caused by contaminated water or food, used needles, or unprotected sex. Three hepatitis viruses – known as A, B and C – cause about 90% of acute hepatitis cases in Canada. We offer hepatitis B vaccinations for students in Grade 7.

HPV is a virus that can cause cancer of the cervix, vagina and vulva as well as genital warts. We offer HPV vaccines for students in Grade 7.

Impetigo is a bacterial skin infection. It usually appears around the mouth or nose, but can appear anywhere.

Influenza, more commonly known as the flu, is a serious, highly contagious viral infection.

Lyme disease is a potentially serious illness that is spread to humans by the bite of an infected blacklegged tick (deer tick).

Measles is a very contagious disease and death can occur in 1 of every 1,000 cases. Protect yourself and your family by following Ontario's routine immunization schedule.

MPOX (formerly known as Monkeypox)is a viral illness that is usually spread from animals to humans. Human-to-human transmission can occur through direct contact with MPOX sores, bodily fluids, or respiratory droplets, or through contact with contaminated clothing, bedding, or common items. 

Mumps is a viral disease that begins as an infection of the nose and throat and may spread through the blood to other parts of the body. Mumps is preventable with vaccination. Get vaccinated according to Ontario's routine immunization schedule.

Norovirus is a common, highly contagious virus that causes diarrhea and vomiting. Good hand hygiene is the best prevention against norovirus.

Pertussis (whooping cough) is a serious bacterial infection that affects breathing. It is preventable with vaccination, so be sure to follow Ontario's routine immunization schedule.

Rubella is a highly contagious disease that affects the nose and throat before spreading to glands in the neck and brain. Rubella is preventable with vaccination. Get vaccinated according to Ontario's routine immunization schedule.

Tuberculosis (TB) typically attacks the lungs, but can also affect other parts of the body.

West Nile virus is transmitted to people through the bite of an infected mosquito. Sometimes the virus can cause serious illness, even death. Public Health Ontario tracks cases of West Nile in Ontario.