San Luis Obispo dentist Dr. Michael Colleran died of West Nile virus on Oct. 25, 2026. He is remembered for his humor, kindness, intelligence, generosity and his dedication to his family.
Courtesy of Sean Colleran
San Luis Obispo dentist Dr. Michael Colleran knew how to make people laugh — especially during difficult moments. His humor was part of his strength, according to his son Sean Colleran.
“He was very strong as a person,” Sean said. “He would always try and keep everybody around him calm — somebody we could lean on and depend on.”
After a 2-month-long battle with West Nile virus, Colleran died on Oct. 25 at the age of 63. He is remembered for his sense of humor, kindness, intelligence, generosity and dedication to his family.
“I just always loved how kind and funny he was,” Sean said. “He would always be there to listen and give some solid advice.”
San Luis Obispo dentist Dr. Michael Colleran died of West Nile virus on Oct. 25, 2026. He is remembered for his humor, kindness, intelligence, generosity and his dedication to his family. Courtesy of Sean Colleran West Nile Virus in California
Near the end of summer, Colleran visited Anaheim about a week and a half before he got sick.
The virus started with flu-like symptoms and morphed into a stomach flu. He soon developed neurological symptoms that resembled a stroke. He was later intubated, and within a few weeks, he was diagnosed with West Nile virus.
After Colleran spent a month at Santa Barbara Cottage Hospital, his family moved him to a long-term acute care facility in West Covina, Los Angeles County, where he died.
Colleran was one of 29 people to die of West Nile virus in California in 2026, according to the California Department of Public Health.
Statewide, 502 people had tested positive for the mosquito-borne illness this year. Only one person contracted the virus in San Luis Obispo County.
Death is not necessarily a common outcome of West Nile virus.
This summer, West Nile virus experienced a five-year high of activity in California, according to the state. The spike has not necessarily impacted San Luis Obispo County, according to the county Public Health Department.
“Increased statewide activity does not necessarily mean every county experiences the same level of transmission,” the county said in a statement. “Local activity depends on several factors, including mosquito populations, weather conditions, temperature, water availability and the presence of infected birds and mosquitoes.”
The county encouraged people to take precautions to protect themselves from mosquito bites. They should use insect repellant containing an EPA-registered active ingredient, including DEET, picaridin, IR3535 or oil of lemon eucalyptus, and follow the directions on the product label. Wear protective clothing, especially at dawn and dusk, and eliminate standing water around the home.
Mike and Cyndee Colleran shared a love of boating. They were married for 41 years before he died of West Nile virus on Oct. 25, 2026. Courtesy of Sean Colleran SLO dentist always showed up for his family
Colleran met his wife, Cyndee, in the 1980s while they served as missionaries in Michigan for the Church of Jesus Christ of Latter-day Saints. They got married nine months later and moved to California, she said. They were married for 41 years.
Cyndee taught Colleran how to water ski, and the couple loved to spend time together at Lake Shasta. They eventually bought a boat, and they returned to the lake every year.
“He was just a fun, fun person,” Cyndee said.
The couple eventually adopted their two children, Megan and Sean.
“He was such a good dad,” Sean said. “He’d always be joking around.”
Sean spent lots of time with his dad — visiting the lake or Disneyland, playing card games, and watching old TV shows like “The Twilight Zone,” he said.
Colleran was also a “fix-it guy,” Sean said.
About two years ago, the side-view mirror on Sean’s car wouldn’t stay in place, so he asked his dad for help. Colleran chewed a piece of Bazooka bubble gum and used it to stick the mirror back in place. The mirror still hasn’t budged.
“He would find the most simple, easy way to figure something out, and he’d just do it,” Sean said. “He was amazing for that.”
Mike and Cyndee Colleran on their wedding day in 1985. They were married for 41 years before he died of West Nile Virus on Oct. 25, 2026. Courtesy of Sean Colleran Building a dentistry practice in San Luis Obispo
Colleran chose to become a dentist because he wanted to work in the medical field in a job that allowed him to spend weekends and evenings with his family, Cyndee said.
“Dentistry just seemed to fit all that,” she said.
He ran a private practice in Placerville, but the couple wanted to return to San Luis Obispo County — where they lived when Colleran attended Cal Poly.
“We’d always, always loved it here,” she said. “The community is very accepting.”
He eventually bought his San Luis Obispo dental practice in 2001 at 1250 Peach St. The whole family moved to San Luis Obispo County full-time in 2002 and lived in Templeton.
Colleran was dedicated to learning and expanding his practice, Cyndee said. He took classes in orthodontics, sleep apnea treatment and laser dentistry. He even became an instructor in laser dentistry later in his career, she said.
“He was just always expanding his knowledge and what he could offer his patients,” she said.
He strove to be a “no-pain dentist,” she said.
“He was very proud of making every effort to make everything as painless as possible, so that people would be comfortable coming to him,” Cyndee said.
Colleran was a man of few words, so he hired a “chatty” staff to make his office feel welcoming to patients, she said.
“There was always a lot of laughter going on in that practice,” Cyndee said. “He wasn’t a real serious guy. He liked to keep things light.”
The practice experienced a major upheaval in 2024 when it was destroyed in an arson fire, forcing Colleran to temporarily relocate the business.
They repaired the building and moved back in about a year ago, but the Colleran family is still paying off the loans, Cyndee said.
Now, the dental practice is up for sale, Cyndee said. In the meantime, a few of their dental friends are volunteering to cover appointments so the practice can continue serving patients.
Mike Colleran, left, smiles for the camera with his wife Cyndee and their son Sean. The San Luis Obispo dentist died of West Nile virus on Oct. 25, 2026. Courtesy of Sean Colleran Help the Colleran family with medical bills
The community can support the Colleran family by donating to a GoFundMe to cover medical bills and business loans.
The family faces significant medical bills from a heart attack Colleran also suffered recently and his fight against West Nile virus.
Find the GoFundMe online at gofundme.com/f/support-cyndee-after-mikes-passing?cp_src=d.
“Any support, whether through a donation or by sharing this fundraiser, would mean so much to the Colleran family,” the GoFundMe said. “Your kindness and generosity can help give Cyndee a little more breathing room as she mourns and begins to face the days ahead.”
Sean’s fiancée, Megan Mathews, started the fundraiser on behalf of the family.
Colleran’s family will host a celebration of life at the Church of Jesus Christ of Latter-day Saints in Atascadero at 2600 Ramona Road on Nov. 14 at 10 a.m.
“We have strong faith, and that’s what gets me through,” Cyndee said. “His spirit is in a better place, and we will see him again.”
San Luis Obispo dentist Michael Colleran and his wife, Cyndee Colleran, smile for the camera. They were married for 41 years before he died on Oct. 25, 2026. Courtey of Sean Colleran
This story was originally published October 31, 2026 at 10:00 AM.
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Stephanie Zappelli is the environment and immigration reporter for The Tribune. Born and raised in San Diego, they graduated from Cal Poly with a journalism degree. When not writing, they enjoy playing guitar, reading and exploring the outdoors.