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Over the years, Ontario's measles cases have been rare, owing to the high immunization coverage. However, that favorable situation has changed in Canada's most populous province.
This new report from the public health ministry describes the epidemiology of measles in Ontario, focusing on the current multi-jurisdictional measles outbreak.
As of March 26, 2025, 557 measles cases (464 confirmed, 93 probable) had been reported in Ontario since October 28, 2024.
This is a significant change from the past decade.
Between 2013 and 2023, 101 confirmed measles cases were reported in Ontario, while 64 cases were reported in 2024.
Just to the south in the United States, Minnesota, Michigan, Ohio, Pennsylvania, and New York have also reported measles cases, but on a far reduced scale.
In 2025, a total 483 confirmed measles cases were reported by 20 U.S. jurisdictions.
As of March 30, 2025, the U.S. Centers for Disease Control and Prevention maintains a global measles outbreak Watch-Level 1, Notice, which does not include Canada.
The CDC recommends that most people get two doses of the MMR vaccine to protect against this infectious disease. Measles vaccines are generally available at travel clinics and pharmacies in the U.S.
As the seventh cholera pandemic continues in three World Health Organization (WHO) regions in late March 2025, countries in Africa have been severely impacted by these acute diarrheal infections.
Since January 2025, the Republic of Angola has been experiencing a significant cholera outbreak. The disease can cause severe acute watery diarrhea, resulting in considerable morbidity and mortality.
As of March 23, 2025, a total of 8,543 cases and 329 deaths have been reported, resulting in a case fatality rate of 3.9% in this northwestern African country.
The outbreak has spread rapidly to 16 of Angola's 21 provinces, with the highest burden among those under 20.
Angola shares borders with the Democratic Republic of Congo and Zambia, both of which are currently experiencing cholera outbreaks.
As of March 29, 2025, the WHO's Disease Outbreak News wrote, 'Given the rapidly evolving nature of the outbreak, the ongoing rainy season, and cross-border movement with neighboring countries, the WHO assesses the risk of further transmission in Angola and surrounding areas as very high.'
Furthermore, due to the cholera outbreak, the WHO does not recommend travel or trade restrictions to and from Angola.
To reduce this outbreak, Angola's Ministry of Health, with support from others, carried out a five-day reactive vaccination campaign in January 2025. Over 900,000 people were vaccinated, and 700,000 additional doses of oral cholera vaccines arrived in the country in mid-March for a second reactive campaign.
While the U.S. CDC has not issued a Travel Health Advisory regarding Angola's outbreak, the agency writes, 'cholera vaccination may be considered for children and adults traveling to areas of active cholera transmission.'
In the United States, cholera vaccines are offered at travel clinics and pharmacies in 2025.
According to the Global Polio Eradication Initiative (GPEI), several countries reported new circulating vaccine-derived poliovirus type 2 (cVDPV2) cases.
Nigeria reported three cases as of March 26, 2025, with onset dates in January and February, bringing its total for 2025 to ten instances. Last year, 98 cVDPV2 cases were reported.
Angola recorded its first case of 2025.
Additionally, GPEI reported that wastewater surveillance in Israel detected a positive cVDPV2 sample collected in the Central province. Genetic analysis indicates that this virus is not related to recent environmental detections in Europe or Gaza, but is most closely linked to a strain that originated in Nigeria's Zamfara state.
Israel is conducting a thorough field investigation to strengthen disease surveillance (including for acute flaccid paralysis cases in health facilities) and identify any residual subnational immunity gaps in this densely populated area.
And in Pakistan, one of two countries in which polio is still endemic, 24 Wild Polio 1-positive environmental samples were recently collected.
The total number of WPV1 cases in 2025 is six. Last year, Pakistan reported 24 WPV1 cases.
As of March 29, 2025, the U.S. CDC recommends international travelers speak with a travel vaccine expert before visiting any polio-risk area.
Historically, most mainland Australian states have reported cases of locally acquired dengue fever. In January 2025, 261 notifications of dengue cases throughout Australia were received.
So far this year, the disease has significantly impacted Australia's northeast coast.
Queensland Health declared a Dengue outbreak centered in Townsville City LGA on February 19, 2025, and as of March 25, 2025, 11 cases (9 confirmed, two probable) had been reported.
Townsville Public Health Unit director Dr Steven Donohue said in a recent press release that they have started a full-scale dengue outbreak response.
Teams from Townsville HHS and Townsville City Council are talking to residents in nearby homes in North Ward to warn them of the dengue outbreak, inspect their properties, and carry out any mosquito-mitigation activities," Dr Donohue said.
"It is important for residents to take dengue precautions."
"Therefore, it's imperative to tip out anything holding water around your house. They'll breed in junk, tyres, and pot plant bases. Tip those out. Have a dry yard as much as possible.
"Make sure to spray dark, damp hiding places inside your house. Use surface spray or long-acting insecticide – under the sink, in the bathroom, or the laundry, all of those hiding places. That's a great way to get rid of these mosquitoes."
Dr. Donohue added that it is vital for anyone feeling unwell to see a doctor.
As of March 29, 2025, dengue vaccines are authorized in Australia and most Asia / Pacific countries.
According to recent data from Japan's public health institute, the number of infectious gastroenteritis cases caused by norovirus and other pathogens in Japan has reached the highest level in ten years.
As of mid-March 2025, there were 34,609 norovirus cases reported by the National Institute of Infectious Diseases.
According to Japan's Ministry of Health, Labor and Welfare, most reported cases of infectious gastroenteritis are viral, primarily affecting infants and school-age children.
Like "infectious diarrhea" in Western terminology, norovirus is classified as a causative pathogen and a foodborne infection.
Historically, norovirus cases in Japan are detected in early winter, peak in December due to viruses like RSV, have a smaller peak in spring associated with rotavirus, and continue into early summer.
Bacterial infections, such as Vibrio parahaemolyticus, are more common in summer.
In summary, the Ministry says these infections can be categorized as sporadic or epidemic diseases in the region or as part of foodborne infectious diseases.
The U.S. CDC says norovirus is the leading cause of vomiting and diarrhea from acute gastroenteritis and stomach inflammation among people of all ages in the U.S.
Norovirus causes 58% of foodborne illnesses acquired, resulting in about 900 deaths, mostly among adults aged 65 and older, each year.
Furthermore, the CDC has reported 12 norovirus outbreaks on cruise ships. In 2024, 18 norovirus outbreaks were confirmed on U.S.-based cruises.
As of March 28, 2025, the U.S. government has not approved a norovirus vaccine for commercial use.
Even with a vaccination requirement to visit most Yellow fever endemic countries, the Pan American Health Organization (PAHO) has issued a new Epidemiologic Alert regarding increased human cases in 2025.
As of March 26, 2025, the PAHO wrote that health officials have confirmed 131 Yellow fever (YF) cases in four countries, 53 of them fatal, indicating a 40.4% case-fatality rate.
Brazil has 81 confirmed cases, 31 of which have been fatal.
The other YF cases have been reported in the Plurinational State of Bolivia, Colombia, and Peru.
In 2025, YF cases have also been detected in the state of São Paulo in Brazil and the department of Tolima in Colombia, regions outside the Amazon region.
The PAHO/WHO wrote 'It is essential that countries achieve vaccination coverage of at least 95% in populations in at-risk areas, in a homogeneous manner, and that health authorities ensure that they have a strategic reserve inventory that allows them to maintain routine vaccination and, at the same time, respond effectively to possible outbreaks.'
When departing to South America from the United States in March 2025, YF vaccination services are offered at most travel clinics and pharmacies. Once immunized, a certificate that is essential to enter certain countries will be generated.
Tuberculosis (TB) is the leading cause of death from a single infectious agent worldwide, including in England.
The UK Health Security Agency (UKHSA) report announced on March 24, 2025, reveals that TB remains a significant public health concern in England.
Data indicates that reported TB notifications increased by 13% in 2024, from 4,850 to 5,480 people, compared with 2023.
The most significant geographic increases were in London and the West Midlands
The UKHSA writes, ' If this rate of increase persists, the UK risks losing its WHO low incidence status of 10 cases per 100,000 population.'
According to the UKHSA, there is a strong association between the increase in TB incidence and the rise in migration, with about 81% of all notifications in 2023 coming from people born outside the UK. Work is underway to identify the optimal and most cost-effective control and prevention strategies to tackle this increase.
One tactic to reduce TB cases in children listed by the UKHSA is to optimize the use of Bacillus Calmette–Guérin (BCG) vaccines provision through commissioning and specification to include vaccinating infants at four weeks of age. While about 50% effective, BCG vaccination is an inexpensive defence against treating TB cases.
The global average cost for BCG vaccination is about $5.00. According to USAID, treating a tuberculosis case in the U.S. costs about $20,000, and a drug-resistant tuberculosis case can cost over $150,000.
