LETTERS TO THE EDITOR

 

Cholera outbreak in Thailand during the past 25-year period, a summary on epidemiology

Brotes de colera en Tailandia durante los últimos 25 años: un resumen epidemiológico

 

---

Palabras clave: Cólera. Tailandia.

Key words: Cholera. Thailand.

---

 

Dear Editor:

Cholera is an old well-known bacterial diarrhea. It is a severe diarrhoeal disease transmitted via the feco-oral route and commonly associated with poor sanitation (1). Every year, more than 100,000 cholera cases and 2,000-3,000 deaths are officially reported to World Health Organization (WHO) (2). The real figures for cholera are thought to be much higher, however, due to underreporting and other limitations of surveillance systems (2). Cholera is caused by two of a gram negative bacterium, Vibrio cholera (2). Of interest, between the years of 1995 and 2001, the WHO reported 1,829 cases of cholera in developed countries, the majority of which were imported (1). Presently, many tropical countries are classifies as risk areas for cholera (3). In Thailand, cholera is a disease under surveillance. A recent study indicated that up to 65% of the Thai adults had IgG and IgM antibodies to this disease (4). There have been sporadic reports on the outbreak of this infection for years. The aim of the study concerns the epidemiology of cholera in Thailand.

Here, the author performed a summarization on the previous reports on the outbreak of cholera in a 25-period, from 1982 to 2007. A literature review to find the reports on outbreak of hepatitis A in during that period in Thailand was performed. The author used the electronic search engine PubMed (www.pubmed.com) in searching for the literature. The author also reviewed the published works in all 256 local Thai journals, which are not included in the international citation index by the database Thai Index Medicus. According to this study, there are at least 11 reports of overall 860 cholera cases (435 males and 425 females; 484 children and 374 adults) (5-15) on the outbreak of cholera during 1982 and 2007 (Table I). There had been continuous reports on sporadic cholera outbreak in Thailand between 1983 and 1995. However, there was no report after 1996. The numbers of reported cases in the outbreak range from 11 cases to 264 cases. The settings of outbreaks can be found in many settings, especially in schools (6/11 reports). The period of epidemic ranged from 1 to 15 months, with the common period in the rainy season of Thailand. The common sources of infections can be seen in 7 reports (food 2, water 2 and hospital device 3). There are 786 symptomatic (all presented with diarrhea) and 74 asymptomatic cases. Swab cultures were used for confirmation of diagnosis in all cases. Biotype El Tor, serotype Inaba with multiple antibiotic resistant is the main microbiological result. The common treatment for all cases was intravenous fluid administration. Death can be seen in 13 cases (1.5%).

Cholera is an important problematic tropical diarrhea. According to this study, there is a trend of decrease report of cholera outbreak in the last decade in Thailand. This finding might imply the improvement in health education and control of gastrointestinal infection in Thailand. Concerning the reported outbreak in this study, there are both reports of the outbreak among the children and adults. Of interest, the trend of outbreak changed from community into a closed single setting. Of interest, there is a repeated outbreak in a same setting (8,13), a home for mentally handicapped. The root cause analysis revealed the contamination in water in bathroom. Due to the fact that this setting is a center for mental retard children, the common source due to ingestion of bath water is proposed (13).

Nosocomial infection can also be seen (5,6,10). In identified nosocomial cases, untreated contaminated food and drinking water are common (8,11,13,15). Both hospitalized patients and medical personnel were identified to be the infected cases (8,11,13,15). Indeed, cholera as nosocomial infection is not frequently reported (16,17). This topic should be another focus in hospital infection control. Hospital water point-of-use filtration is believed to be effective preventive tool for cholera nosocomial infection (18).

Due to the improvement in intravenous fluid treatment, the fatality is low. There is no report of fatality in the recent outbreaks. Indeed, treatment requires immediate replacement of the massive fluid loss before diagnostic studies are ordered (19). No antibiotic is indicated and it can be seen that the pathogens are usually multiple antibiotic resistant. It seems that treated running tap water and well cooking are important in prevention of cholera outbreak. The author hereby concludes that provision of clean water and control of possible contamination in food and drinking water as well as eating and drinking sanitation is still the heart of infectious control for cholera.

 

V. Wiwanitkit

Department of Laboratory Medicine. Faculty of Medicine. Chulalongkorn University. Bangkok, Thailand

 

References

1. Steffen R, Acar J, Walker E, Zuckerman J. Cholera: Assessing the risk to travelers and identifying methods of protection. Travel Med Infect Dis 2003; 1 (2): 80-8.        [ Links ]

2. Fournier JM, Quilici ML. Cholera. Presse Med 2007; 36 (4 Pt 2): 727-39 (Epub 2007 Mar 1).        [ Links ]

3. Cook CG. Gastroenterological emergencies in the tropics. Baillieres Clin Gastroenterol 1991; 5 (4): 861-86.        [ Links ]

4. Suthienkul O, Poomchart A, Kositanont U, Siripanichgon K, Vathanophas K. ELISA for seroepidemiological study of exposure to Vibrio cholerae of population in Krabi Province, Thailand. Asian Pac J Allergy Immunol 1992; 10 (1): 55-60.        [ Links ]

5. Techapaitoon S, Powtongsook V, Duangploy S. Outbreak of cholera epidemiology in Samutprakarn Hospital. Bull Dept Med Serv 1983; 8 (6): 421-5.        [ Links ]

6. Swaddiwuthipong W, Tungcharoensilp S, Kum-au S, Paholthep C, Ruthtavorn A, Inmuang Y. Eltor cholera outbreak in Muang District, Khonkaen Province in 1987. Commun Dis J 1987; 13 (3): 239-51.        [ Links ]

7. Swaddiwuthipong W, Dejdecho P, Ruksapol S, Sukhkeau T. An outbreak of nosocomial cholera in a 755-bed hospital. Bull Dept Med Serv 1987; 12 (10): 527-34.        [ Links ]

8. Swaddiwudhipong W, Kunasol P. An outbreak of nosocomial cholera in a 755-bed hospital. Trans R Soc Trop Med Hyg 1989; 83 (2): 279-81.        [ Links ]

9. Swaddiwudhipong W, Limpakarnjanarat K. An outbreak of El Tor cholera in an institution for the mentally retarded in Nonthaburi, June-July 1987. J Med Assoc Thai 1991; 74 (6): 306-10.         [ Links ]

10. Swaddiwudhipong W, Akarasewi P, Chayaniyayodhin T, Kunasol P, Foy HM. Several sporadic outbreaks of El Tor cholera in Sunpathong, Chiang Mai, September-October, 1987. J Med Assoc Thai 1989; 72 (10): 583-8.        [ Links ]

11. Swaddiwudhipong W, Akarasewi P, Chayaniyayodhin T, Kunasol P, Foy HM. A cholera outbreak associated with eating uncooked pork in Thailand. J Diarrhoeal Dis Res 1990; 8 (3): 94-6.        [ Links ]

12. Kraisriwatana J, Supachutikul A. Precaution against nosocomial spread of cholera in Udornthanee Hospital. J Med Assoc Thai 1992; 75 (Supl. 2): 35-7.        [ Links ]

13. Swaddiwudhipong W, Jirakanvisun R, Rodklai A. A common source foodborne outbreak of E1 Tor cholera following the consumption of uncooked beef. J Med Assoc Thai 1992; 75 (7): 413-7.        [ Links ]

14. Jiraphongsa C, Jinwong T, Sangwonloy O, Ungchusak K, Pariyachad W, Jamjumrus S, et al. A second outbreak of cholera in the home for mentally handicapped, Nonthaburi. J Med Assoc Thai 1994; 77 (5): 249-52.        [ Links ]

15. Prathana Y, Kanjanahareutai S, Rahule S, Ruangvisut K. An outbreak of EI for cholerae in Rajavithi Hospital. Bull Dept Med Serv 1995; 20 (9): 322-8.        [ Links ]

16. Hernández JE, Mejía CR, Cazali IL, Arathoon EG. Nosocomial infection due to Vibrio cholerae in two referral hospitals in Guatemala. Infect Control Hosp Epidemiol 1996; 17 (6): 371-2.        [ Links ]

17. Ryder RW, Rahman AS, Alim AR, Yunis MD, Houda BS. An outbreak of nosocomial cholera in a rural Bangladesh hospital. J Hosp Infect 1986; 8 (3): 275-82.        [ Links ]

18. Ortolano GA, McAlister MB, Angelbeck JA, Schaffer J, Russell RL, Maynard E, et al. Hospital water point-of-use filtration: A complementary strategy to reduce the risk of nosocomial infection. Am J Infect Control 2005; 33 (5 Supl. 1): S1-19.        [ Links ]

19. Keen MF, Bujalski L. The diagnosis and treatment of cholera. Nurse Pract 1992; 17 (12): 53-6.        [ Links ]