Reporting by Mola Lenghi, Jose Diaz Jr., Russell Midori, Alyssa Estrada

Since the start of the year, at least 10 American tourists have died while vacationing in the Dominican Republic, and questions are also being raised about several more deaths in 2018. Some of the deaths reportedly occurred after the visitors complained of feeling ill after eating a meal or drinking out of the hotel minibar. The U.S. embassy in Santo Domingo said there is no proof at this point the deaths are linked.

CBS News spoke on June 18 with César Duvernay, a spokesperson for the Dominican Republic's foreign ministry, who said the cases are isolated out of more than 6 million tourists, and that this doesn't mean the country is unsafe. He noted that the government has a special body focused on tourism safety, with protocols in place that have not changed.

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Several of the deaths were reported to be a heart attack, which health officials say is the most common cause of death for Americans on vacation. CBS News can confirm that attorneys for the families of Nathaniel Edward Holmes and Cynthia Ann Day, who died on May 30, have ordered independent autopsies "to get to the bottom of what's happening." The Washington Post reported last week that the family of Cynthia Schaup-Werner, who died on May 25, is awaiting an independent investigation in the U.S, as well.

Here is what we know so far about the recent deaths of Americans vacationing in the Dominican Republic.

Jerry Curran

Age 78. From Bedford, Ohio.

Died on Jan. 26, 2019 at the Dreams Resort in Punta Cana.

Curran died three days after arriving in the Dominican Republic with his wife. His daughter told WKYC-TV, "He went to the Dominican Republic healthy and he just never came back." His daughter said Curran fell ill after dinner and drinks the night of his arrival and that his cause of death includes pulmonary edema, or fluid in the lungs, which is listed the cause of death for at least three other Americans in the Dominican Republic this year.

Tracy Jerome Jester Jr.

Age 31. From Forsyth, Georgia.

Died on March 17, 2019 while visiting the Dominican Republic.

Jester's death was reported by Atlanta station WSB-TV on July 12. His mother said her son drank a soda that he told her "didn't taste right." His sister, who was vacationing with Jester, called their mother on the night he died and said he was struggling to breathe. Jester's mother feels her son's death is connected to the other American tourist deaths this year, the station reported. Jester's sister said her brother had lupus, but it is unclear if the illness is connected to his death. Jester's death certificate said he died from "respiratory issues."

Robert Bell Wallace

Age 67. From California.

Died on April 14, 2019, at the Hard Rock Hotel & Casino in Punta Cana.

Wallace died after drinking from the minibar in his hotel room at the Hard Rock Hotel & Casino in Punta Cana, his family said. Wallace's cause of death has yet to be determined, but his niece told Fox News her uncle had been in good health before his arrival and he became unwell shortly after drinking a glass of scotch from the minibar in his room and died in a hospital three days later.

Miranda Schaup-Werner

Age 41. From Pennsylvania.

Died on May 25, 2019, at the Luxury Bahia Principe Bouganville Hotel.

The U.S. State Department confirmed Miranda Schaup's death June 4; she died May 25. She was staying at the Luxury Bahia Principe Bouganville Hotel to celebrate her ninth wedding anniversary with her husband. Her family said she collapsed and died after she had a drink at the hotel. Preliminary autopsy results released by Dominican authorities said she had fluid in her lungs and respiratory failure. The FBI is conducting toxicology tests. Less than a week later, two more Americans died at another hotel on the same Bahia Principe resort.

Nathaniel Edward Holmes and Cynthia Ann Day

Age 63 and 49. From Prince George's County, Maryland.

Died on May 30, 2019, at the Grand Bahia Principe La Romana.

The couple were found dead in their hotel room on May 30. There were no visible signs of violence. However, several bottles of medicine were found, such as Galanpertin, Oxycodone, and Loxofen. Holmes and Day had been staying at the Grand Bahia Principe La Romana since May 25. A statement from the Dominican Republic National Police said that an autopsy concluded that the couple had respiratory failure and pulmonary edema, a condition caused by excess fluid in the lungs.

Autopsy results showed some similarities between their cases and Schaup-Werner's. The resort insists the deaths of the three Americans were unrelated.

Leyla Cox

Age 53. From Staten Island, New York.

Died on June 10, 2019, at Excellence Resorts in Punta Cana.

Cox died the day after celebrating 53rd birthday. U.S. Embassy officials told her son her death has been ruled a heart attack, but her son said, "I do not believe it was natural causes."

Joseph Allen

Age 55. From New Jersey.

Died on June 13, 2019, at Terra Linda Resort in Sousa.

Allen's family said he was on good health and traveled to the Dominican Republic frequently. His cause of death has not been released. Allen was there with friends who said he complained about being hot at the pool before going to shower and lie down; he was found dead the next day.

Vittorio Caruso

Age 56. From Long Island, New York.

Died on June 17, 2019, at Boca Chico Resort in Santo Domingo.

Caruso's cause of death is not yet determined, but his sister-in-law told Fox News, "he was brought by ambulance to the hospital in respiratory distress after drinking something." Caruso's family told the New York Post that he was "very healthy" and that "he went to the doctor before he left, and he had no problems."

Khalid Adkins

Age 46. From Denver, Colorado.

Died on June 25, 2019 while visiting the country with his daughter.

Adkins cause of death has not been disclosed. His sister-in-law, Marla Strick, told the Colorado station KDVR-TV that he vomited in his departure plane's bathroom and was hospitalized in Santo Domingo, where she was told "his kidneys were failing." His daughter Mia Adkins wrote on her Facebook page that her father "got super sick," during a visit to the country together.

Tourist deaths in the Dominican Republic in 2018

Mark Hurlbut Sr.'s son says he was told by a Dominican Republic coroner that his father died from heart and respiratory problems last year in Punta Cana. Mark Hurlbut Jr. said his father and his dad's wife felt sick the night before he died. "She woke up, and he didn't," Mark Jr. told CBS Phoenix affiliate KPHO-TV. "She told me that as she found him that he had something green coming from his mouth."

David Harrison died in July 2018 at the Hard Rock Hotel, the same hotel where Robert Bell Wallace died this year. According to the New York Post, Harrison died of pulmonary edema and respiratory failure, but his wife said he felt sick with an upset stomach days before his death and woke up with a full-body sweat on July 14 and couldn't speak.

Yvette Monique Sport, 51, of Glenside, Pennsylvania, died at Bahia Principe Resort in Punta Cana of a heart attack in June 2018. According to the New York Post, her sister said Sport had a drink at the minibar insider her room, went to bed, and never woke up.

Reports of tourists sickened in the Dominican Republic

A New York woman said she became ill and spewed blood, leaving her without any taste buds, after taking a sip of soda from the minibar at Grand Bahia Principe Resort in La Romana in October 2018. This is the same resort where three Americans died in May 2019.

A Colorado couple claims they were sickened at same hotel where three Americans died in May. They have since filed a lawsuit against the owners of the Grand Bahia Principe Hotel La Romana after a doctor determined they suffered insecticide poisoning while vacationing at the hotel in June 2018.

A group of Oklahoma teens from Deer Creek High School on a senior trip fell "violently ill" on June 8 at the Hard Rock Hotel and Casino in Punta Cana, the same hotel where Harrison and Wallace died.

A Florida man who went to the Caribe Club Princess Beach Resort and Spa at Punta Cana in May claims he became "severely sick with stomach pain while swimming in the pool."

More than 50 Jimmy Buffett fans from Oklahoma became ill during an all-inclusive trip to Hotel Riu Palace Macao in April. Some people in the group tested positive for salmonella, while others did not. Symptoms included vomiting, diarrhea, chills and fever.