GUELPH – Wellington-Dufferin-Guelph Public Health (WDGPH) is keeping an eye on five reportable diseases that showed a marked increase in 2024.
The board of health received a report on Feb. 5 from manager of infectious diseases Lilliana Marinko that listed the diseases as:
- salmonella;
- giardia;
- pertussis;
- lyme disease; and
- shigella.
“Why should we pay attention? These are all preventable,” Marinko said.
“They impact the vulnerable population – the elderly, infants and people who are immunocompromised – and there’s potential for outbreaks.”
Salmonella
Salmonella is predominately spread by eating contaminated foods, such as under-cooked poultry and meat, raw and under-cooked eggs, raw milk or milk products, or ingesting water contaminated with infected animal feces.
Anyone can get it – and it causes diarrhea – but the vulnerable population is more at risk of complications.
WDGPH numbers were pretty flat in 2019 and 2020, hovering around 15 cases per 100,000 people.
There was a dip to 10 cases per 100,000 in 2021, then it went back to 15 in 2022 and 2023, and jumped to 20 cases per 100,000 in 2024.
Giardia
Giardia also causes diarrhea and poses the same threat to vulnerable populations.
It may be found in water, food, soil or on surfaces and hands contaminated with feces. It is primarily spread by ingesting contaminated water, such as lake or river water. It can also be spread by touching contaminated objects.
WDGPH’s infection rates have been higher than the provincial average since 2019, but held steady at 10 cases per 100,000 people from 2019 to 2021. The rate rose to 13 in 2022, went down to eight in 2023, but jumped to 17 cases per 100,000 people in 2024.
Pertussis
The province and WDGPH both saw an increase in cases of pertussis, or whooping cough, in 2023, with WDGPH reporting 23 cases.
That more than doubled to 51 cases in 2024 with the largest group affected being those aged 10 to 14.
While pertussis has declined over the years due to vaccines, “in Ontario, pertussis illness circulates at a low level of activity within communities, however, increases occur cyclically every two to five years,” Marinko’s report states.
Lyme disease
Lyme disease is spread by the blacklegged tick and cases in the province and in the WDGPH region have been increasing from two cases per 100,000 people in 2019 to eight per 100,000 in 2024.
Symptoms include fever, headache, fatigue and rash, and if left untreated, can spread to the heart, joints, and nervous system.
Most cases occur in warmer months, but climate change has allowed ticks to spread geographically.
Shigella
Shigella causes prolonged or bloody diarrhea and is commonly transmitted by ingesting contaminated food or water.
“Young children, travelers, men having sex with men, the underhoused, and individuals with weakened immune systems are most at risk of infection,” states the report.
There were 0.5 cases per 100,000 people in the WDGPH region in 2022.
The rate jumped to almost two cases per 100,000 in 2023 and that’s where it remained in 2024.
“Health inequities create conditions for infectious disease transmission that can contribute to the unequal burden of illness in communities,” and lead to poorer health outcomes for vulnerable populations, states the report
Marinko said the best protection against these diseases is hand washing, vaccination, safe drinking water, being tick smart and practicing food safety.
