I occasionally dabble in genealogy, the only hobby I have that has nothing to do with natural history or science. I’ve been most interested in my mother’s side of the family, which was a big mystery even when my grandmother was alive. My mom was an only child, but her mother came from a large family — of which only one sister was known. All her other siblings, cousins, ancestors…my grandmother was unclear on all their names or what became of them. All I knew was that she was raised on a farm in Amherstburg, Ontario (she remained a Canadian citizen her whole life) but her immediate family had come to live in Detroit sometime after 1900.
I began with her parents Henry Dubey and Annie Deneau. My grandmother said she thought they died of the flu — presumably the influenza pandemic of 1918. I finally found out they actually both died in early 1924: Henry on February 23, Annie on March 6, not of the flu, but of smallpox. A little research revealed that there was an outbreak of smallpox in Detroit from December 1923 to around June 1924, with well over 1,000 cases. The most fatal period was in early 1924.
It wasn’t until recently that I came across an article that noted that the most virulent portion of this epidemic was started by a single undiagnosed case in Windsor, Ontario; this person died on February 11. Smallpox moves fast, and the short time frame between this death and that of my great-grandfather made me curious. I was intrigued when I found an old medical journal article on the epidemic  that identified the first victim as “GD.”
I had already done substantial work on Henry Dubey’s side of the family, as he was directly descended from one of Canada’s original pioneers, Mathurin Dubé. I had no records of close relatives of Henry with the initials GD, so before I started working on cousins, I thought I’d take a look at the Deneau’s, my great-grandmother’s family. This was something I’d not tackled in depth, because this was an extremely prolific family — Essex County, Ontario is still chock-full of Deneaus. I caught a lucky break when I found another medical journal paper . Among a number of gruesome photos of Windsor victims was one of a survivor noted as a “roomer in the Gordon Deneau household.”
Gordon Deneau was my great-grandmother Annie’s brother.
Unfortunately, Gordon had an unusual case of smallpox. He became ill on February 2, 1924, and after he died on February 11, the local paper invited people to his funeral. It wasn’t until attendees began coming down with the disease about a week later that health officials realized Gordon’s illness had been smallpox and many people had been exposed. Through death records and newspaper archives, I was able to find many relatives and their in-laws and relatives who died in Windsor, Amherstburg, and other nearby communities. One article noted that 21 close relatives of Gordon Deneau died. Another mentioned that 8 of Antoine Deneau’s 14 children died in the epidemic; Antoine was my great-great-grandfather, and Annie and Gordon’s father.
It’s hard to imagine today the horror that must have penetrated my family. A recollection from a Windsor resident gives some hint at the dread they must have felt. Below I’ve listed the close relatives that died in a five-week period. I have come up with only 13 siblings in Annie’s family and 7 deaths, but the newspaper article (commemorating Antoine Deneau’s 92nd birthday in 1931) could be inaccurate. Note also that Annie and Henry were not the only Dubey/Deneau intermarriage.
Gordon Deneau, my great-grandmother Annie Deneau’s brother, dies undiagnosed on February 11.
Henry Dubey, my great-grandfather (Annie’s husband), dies February February 23. So does John Shaw, Gordon Deneau’s brother-in-law, and John’s sister Clara Shaw.
Virginie Dubey Deneau, Henry Dubey’s sister and the wife of Annie’s brother John dies February 24.
Albert Deneau, Annie’s brother and twin of Gordon, dies March 1. Reaford Deneau, Albert’s son, dies the same day.
Ida Deneau Cox, Annie’s sister, dies March 2. So does Claire Shaw, wife of John Shaw (Gordon Deneau’s brother-in-law).
Annie Deneau Dubey dies March 6. So does Adolphus Shaw, brother of Claire Shaw.
Rosalie Gibb Shaw, wife of Ernest Shaw (John and Clara Shaw’s brother) dies March 11.
Frances Cox, Ida Deneau Cox’s young daughter, dies March 15.
Augustus Deneau and Joseph Deneau , two more of Annie’s brothers, die March 24.
Another of Annie’s sisters, Rosanah Deneau, disappeared and it was implied she died in this epidemic as well. She was likely married at the time, and I have not found her married name yet.
There were 67 cases of smallpox in Windsor (it’s not clear if this also includes Amherstburg), of which 32 people died. In Detroit, there were 105 deaths from 795 cases that occurred between March 16 and June 1, 1924; how many other than my great-grandparents were derived from the Deneau outbreak isn’t known. Neither Canada nor Michigan had compulsory vaccination at the time, although the border between Detroit and Canada was closed for a time to those not able to prove they had been vaccinated. In Detroit, over a quarter of the population was unvaccinated and another 41% needed boosters. All deaths were people who had not been vaccinated, or had not been recently re-vaccinated. As a result of this outbreak, 50,000 people in Windsor and about 750,000 in Detroit were vaccinated. For at least 20 years after than, smallpox cases never exceeded 100 in Detroit.
Maybe my grandmother wasn’t much of a family person, given her vagueness on other members. In 1924, she was 33 and married, and my mother was 4 years old. Had she been closer to the family, perhaps she would have attended her uncle’s funeral, and this story would have had to been told by someone else.
 Adams, F. 1924. The epidemic of virulent smallpox in Windsor and the vicinity. Canadian Medical Association Journal 692-696. (PDF)
 Pierce, C. C. 1925. Some reasons for compulsory vaccination. Boston Medical and Surgical Journal 192:659-695. (PDF)