Why was there an investigation into deaths in Chiang Mai?
An investigation by public health and other authorities was launched regarding a number of unexplained illnesses and deaths identified by Chiang Mai health authorities. These include the deaths of five foreign tourists, one Thai tour guide and illnesses of three people between 11 January 2011 and 19 February 2011.
Six of these people were staying at one hotel. Thai hospital authorities signaled initial similarities between these deaths, and therefore Chiang Mai health authorities began an investigation with assistance from the Thai Ministry of Public Health and international experts. Chiang Mai police also carried out an investigation in line with normal procedures.
Which cases were investigated?
The people who died and fell ill were grouped under four events based on suspected causes as follow:
One American woman, age 33, died on 11 January. Her friend, a Canadian woman, age 29, fell ill but recovered. Both stayed at Hotel ‚ÄúA‚Äù
One French woman, age 25, died on 19 January. She stayed at Hotel ‚ÄúB‚Äù.
a) One Thai woman, age 47, a tour guide, died on 3 February.
b) One New Zealand woman, age 23, died on 6 February and her two female traveling companions, both age 23 and also from New Zealand, also fell ill but recovered. All stayed at Hotel ‚ÄúC‚Äù.
An older couple from the United Kingdom ‚Äì one man (78) and woman (74) ‚Äì both died on 19 February. They also stayed in Hotel ‚ÄúC‚Äù but on a different floor to those in Event 3 and their deaths were almost two weeks after Event 3.
What was being investigated?
Public health authorities examined several issues:
1) The cause(s) of death and illness
2) The source of exposure and any risk factors related to the cause of death or illness
3) Linkages, if any, between these deaths and illnesses
4) Depending on the cause, measures required to reduce future risks
The investigation included clinical, epidemiological, and laboratory information gathering and analyses by national and international experts ‚Äì including those from the World Health Organization (WHO), and the United States Centers for Disease Control (US-CDC) ‚Äì and relevant interviews with friends and family of the affected people.
What were the main findings of the investigation?
‚Ä¢ In summary, the investigation found that one person likely died of a virus. Three people likely died of exposure to pesticides. And the investigation could not fully determine the cause of death for two people. (see specific case findings in Update 5).
‚Ä¢ However, the exact agents that caused the illnesses and deaths can not be identified. The investigation could also not determine exactly how those who fell ill and/or died were exposed to the agents.
‚Ä¢ It is not unusual in such epidemiological investigations that the specific agents causing illnesses are never identified. But laboratory data when considered with clinical symptoms can validate a hypothesis of the likely cause of illness.
Doesn‚Äôt this make Thailand an unsafe place to visit?
These incidents were very unfortunate and we are sincerely sorry they occurred. However they were sporadic events. The overwhelming number of people who visit Thailand enjoy pleasant and safe holidays here. But as in home countries, and with all destinations, inevitably unfortunate incidents occur.
With regards to pesticide usage, we are taking urgent measures to improve safeguards for everyone in an attempt to reduce the risk of such future incidents.
If the cause of these deaths was a pesticide, what is being done now to stop hotels from using them?
The Chiang Mai authorities and the Department of Disease Control are taking the measures below to ensure the safety of both tourists and Thai citizens in residential and agricultural settings. We are confident that such events are sporadic and can largely be averted in the future.
1) A panel will be set up to investigate and recommend stricter measures for the use of chemicals including pesticides in hotel and market areas.
2) A channel to receive notification of illness of tourists and expatriates has been set up. Visitors can post their notification at Chiang Mai Provincial Public Health or call 053-216592. Events will be verified and investigated.
3) Surveillance of hospitalised tourists, already in effect, will be continued and a new protocol for investigation of fatal cases is being adopted.
4) Retailers of household and agricultural chemicals (pesticides) must declare a watch list of products whose procurement and sales are to be closely monitored. The provincial health office will carry out periodic checks on them.
5) Hotel operators must use only licenced pest control companies and their contracts must specify which chemicals are to be used and samples collected and sent for testing by the authorities twice a year.
6) Municipal authorities are to give safety advice and monitor public celebrations where the burning of ritual papers and other materials are performed in communities, temples and shrines as part of traditional festivals.
7) Develop the food safety standard at eateries and among street vendors, especially around the Night Bazaar area, frequented by tourists in Chiang Mai.
8) Health Education Cards to advice tourists about food safety and other health concerns will be made available to foreign visitors to the province.
9) The Ministry of Public Health will use these measures to strengthen its work throughout the country.