Traveling companions Karin Joy Bowerman, 27, and Vietnamese Canadian Cathy Huynh, 26, both died in July at a hospital in the central province of Khanh Hoa’s premier beach town.

An autopsy was carried out on Bowerman while Huynh’s family requested that her body be returned to Canada without examination in Vietnam.

The Tuoi Tre (Youth) newspaper quoted an unnamed Nha Trang police leader as saying that Bowerman died from “breathing failure and circulatory collapse due to brain edema (swelling caused by fluid).

“No toxic traces have been found in her blood and gastric fluids,” the police official said Tuesday.

As no poison was detected in the samples taken, the police would not launch any criminal investigation in the case, he said.

Bowerman and Huynh were working as English teachers in South Korea at the time of their deaths. Their trip to Vietnam was taken during a break from school. Their deaths took place within two days of their arrival in Vietnam.

They were admitted to Khanh Hoa Army and People's Hospital at around 7 p.m. on July 30 with severe vomiting.

Doctors said Bowerman was in more serious condition than Huynh and had vomited around 15 times and her heartbeat was much faster than normal.

Bowerman was transferred to the Khanh Hoa General Hospital with respiratory failure, a fast heartbeat and no blood pressure and pulse. She died at 10:40 p.m. the same day.

Meanwhile, Huynh was discharged from the Khanh Hoa Army and People’s Hospital at 9:30 p.m. and returned to a hotel where she and Bowerman had stayed.

According to the hotel’s owner, Huynh said she was okay and it looked like she was in normal condition until the morning of August 1, when she said she felt tired.

At noon, she took a taxi to the Khanh Hoa General Hospital.

Doctors said Huynh was conscious when she was admitted to the hospital, but it looked like she was dizzy. Her condition got worse and she died early on August 2.

At her family’s request, Bowerman’s body was cremated in Ho Chi Minh City and her ashes have been sent back to the US.

Huynh’s family refused to allow an autopsy or tests on her while in Vietnam, saying there was no need because the results would be the same as Bowerman’s.

On September 14, the Khanh Hoa Justice Department issued a death certificate with the cause of Huynh’s death as “unrecoverable shock due to unknown reason.”

After the autopsy result of Bowerman was announced, Christopher Hodges, the US embassy spokesperson in Vietnam, said the US Consulate in HCMC was in contact with the family and was providing consular assistance.

Bowerman’s autopsy result was announced by Vietnamese police a day after a report by the Post Bulletin of Rochester said US Senator Al Franken was asking the State Department to look into the deaths of Bowerman and Huynh.

In his letter to Secretary of State Hillary Clinton, Franken wrote: "The anguish is heightened by reports that the circumstances surrounding their deaths are similar to others who were traveling in the region and also died suddenly."

The paper said Bowerman’s friends have raised the possibility that the two women were poisoned through exposure to a pesticide or some other toxic substance.

According to an AP report Tuesday, Bowerman’s family and friends have launched a letter-writing campaign to get the US government to seek answers to her death.

Karin Bowerman’s sister, Ashley Bowerman, said their campaign has spread to at least 12 states, the newswire reported.

International media reports have linked the deaths to an incident in Thailand in June in which two Canadian sisters were found dead in their hotel room, covered in vomit, CNN and CDC News reported.

In February 2011, New Zealand resident Sarah Carter, 23, died in Chiang Mai, Thailand, after arriving at a local hospital with low blood pressure, difficulty breathing and dehydration from vomiting, according to the New Zealand television network TV3.

At the Downtown Inn where Carter had stayed, the Bangkok Post said three other visitors – a Thai tour guide and an elderly British couple – had died between January and May 2011.

“In 2011, TV3 traveled to Chiang Mai, Thailand, to search for evidence in the Sarah Carter case. Show producers spoke with Dr. Ron McDowall, a United Nations toxic chemical consultant, who had reviewed Carter's pathology reports and believed she died of pesticide ingestion,” said a CNN report.

Samples collected by TV3 at the Downtown Inn showed moderate levels of chlorpyrifos, CNN quoted McDowall as saying.

The US Environmental Protection Agency says chlorpyrifos can cause nausea, dizziness, confusion and, in high levels, respiratory paralysis and death.

McDowall told CNN the chemical was banned for use in homes and hotels in most countries, but is still legal in Thailand and Vietnam.

The CNN report said the chemical was included in the pesticide sprayed at the Downtown Inn.

"The level of (chlorpyrifos) in this product is quite low and should not normally cause a problem. However, in my work we have found many sprayer companies 'top up' the level of (chlorpyrifos) when they are battling bedbugs in Asia," said McDowall.

The CNN report noted that evidence for the insecticide theory is mounting.

“Thai police recently announced they found traces of the insect repellent DEET in the Belanger sisters' bodies, according CBC. Investigators believe the DEET was added as an ingredient to a popular cocktail served on the island,” it said.

The Downtown Inn was destroyed this year after the Thailand Disease Control Department concluded that three of the deaths were "probably connected to the use of pesticides," according to the Bangkok Post.

Chemical poisoning is very hard to verify, McDowall told CNN.

Investigators with the World Health Organization suspect poisoning is to blame for the spate of deaths, but determining the origin has proven difficult, according to CNN.

Chlorpyrifos' half-life in humans – or the amount of time it takes for half of the original amount disappears – is about one day.

Source: Thanhniennews