Introduction
Typhoid in Tajikistan broke out after the civil war in Dushanbe’s capital city. The report is about the Typhoid Outbreak Investigation in Tajikistan done by the Sanitary Epidemiologic Service (SES). It will discuss the background, and investigation, summarize the key findings and give recommendations to public health for interventions to control the outbreak.
Related Posts
- Exploring the Benefits of Acupuncture in Alleviating Osteoarthritic Pain in Women | Evidence-Based Practice (EBP) proposal
- Enhancing Collaboration Between Healthcare Organizations and Physicians | Analytical Essay Example
- Precautions for Database Security in Healthcare | Expository Essay Example
Background
Typhoid in Tajikistan was first noted in February 1997 when typhoid fevers were reported in the capital city of Tajikistan, Dushanbe, which had a population of about 600,000 citizens by then (Arnold et al. 2007). Despite the fact, the fever was endemic at that time. About 2000 previous cases were reported in two weeks between January 29 and February 11. This was high when compared to the approximately 75 cases which used to be reported every week of the previous month. The hospitals and the polyclinics which served the city by then reported any disease cases noted to the sanitary-epidemiological service (SES). This health unit tracked infectious diseases weekly (Clasen et al. 2007).
The investigators suspected the food and the public water investigation. Given that previous outbreaks of typhoid were associated with beverages and foods sold by street vendors, the government prohibited their sale. Therefore, the investigators narrowed down to the water, where 3822 patients were investigated (Tarr Pe et al. 1999). The investigator conducted epidemiological, microbial, and environmental studies to explain the sudden increase in typhoid fever cases in two weeks.
Investigation of the outbreak
The investigators pursued various lines to get a clue about the typhoid outbreak. The first step was to review known information on the disease, the epidemiological risk factors, and the previous outbreaks.
Case definitions and confirmation of the outbreak
The SES investigators reviewed the cases of typhoid fever reported by the system of notifying disease surveillance and classified the cases by place, person, and time. In identifying characteristics of the typhoid fever outbreak cases, the investigators came up with a definition of typhoid fever as a diagnosis by a physician or blood, stool, or urine Salmonella Typhi isolation of a resident of Dushanbe.
The investigators analyzed the reported cases to the SES with the illness onset since January 1. 3,822 cases were the number of patients that qualified the definition of typhoid fever since January 1. Out of those, the number who had onset illness from 1st to 14th January was 127, and those who had onset illness from January 15 to February 18 was 3,695 (Centre for Disease Control And Prevention 1998).
During the period between January 15 and February 18, among the reported cases, the following symptoms and signs were reported according to Mermin et al. (1999):
- 91% of the cases from sustained fever
- 81% from headache
- 76% of weaknesses
- 73% from chills
- 67% from a loss of appetite
- 51% of abdominal pain
- 39% from vomiting
- 30% from diarrhea
- 6% from rose-colored spots
- 31% from the stool, blood, and urine cultures (1,145 cases).
Methods of data collection
During the data collection, hypothesis-generating detailed interviews were done to find out suspicious and common exposures among the typhoid fever sample patients. The interviews were conducted on 10 culture-confirmed illness patients who resided in the catchment areas of 5 different polyclinics and varied from 5-69 years old. There were 6 female patients, and the patients showed symptoms during the first two February weeks (Hamilton 1997).
Hypothesis generation and the type of outbreak
From the interviews, it was revealed that all the patients had bought groceries from markets that were state-approved. Moreover, four of the patients had bought food from street vendors. However, no social event, street vendor, market, or restaurant was identified as common among all the interviewed patients.
Furthermore, the patient’s households included in the interviews were given public water, but only one reported occasional cloudiness and foul smell. However, only one had gone out of the city 6 weeks before the outbreak, and seven had visitors from outside Dushanbe because of Ramadan. No patient knew the other, and two knew someone with a similar illness. The investigators hypothesized public water supply was the typhoid fever source in the city of Dushanbe. This is because of the widespread city occurrence affecting all age groups and both sexes. The suspicion was heightened due to the interviewee’s complaints about the public water. This prompted the investigators to do environmental and epidemiological health studies to prove their hypothesis.
Testing of the hypothesis by epidemiologic study
In testing their hypothesis of the public water system as the source of the typhoid outbreak in the city, the SES investigators did a case-control study from March 24. All patients hospitalized in Dushanbe with typhoid fever were enrolled in the case-control study. A case in the study was defined as an illness that included the following:
- a) Clinical criteria
- I) Symptoms and Signs indicative of typhoids, such as stomach pains, weakness, headache, rose-colored rash, and appetite loss
- II) Sustained fever, i.e., oral temperature >38.5c for more than 7 days
III) Culture for blood or stool positive for Salmonella Typhi
- b) Restriction on place, time, and person
- I) Onset of the symptoms after February 1
- II) Dushanbe resident
III) Person having earliest symptoms onset in the household (Asia-Pacific Symposium On Typhoid Fever, Pang, Koh & Puthucheary 1992).
Case/control study including Odds ratio and how the controls were recruited
The interview was done with the case patients within five days of admission to the hospital, using a standardized questionnaire by an SES-trained interviewer. The questions focused on the one-month exposure before the illness onset. The investigators then selected, within five days, neighborhood control subjects in houses where no one had experienced fever for less than three consecutive days during the 90 previous days.
Sarasombath et al. (1995) observed that recruitment of the control subjects was done from door to door systemically, beginning at the house of the case patient; matching of the control subjects was then done with the age group of case patients. 2-3 control subjects identified were assigned one case patient.
According to Murdoch et al. (1998), an interview of the control subjects was conducted using the same questionnaires as case patients. A difference in information exposure was requested 30 days before the interview. Between 24th March and April 7, 127 control subjects and 45 case patients were recruited in the case-control study.0.05 was set as the p-value as the statistically significant cut-off (Taylor et al. 1999). From the analysis case- patients and control subjects were similar concerning sex, age, and nationality. However, exposure to potential risk factors for Salmonella Typhi infection differed between the two groups.
From the matched case-control study, infection was associated with drinking water not boiled 30 days before symptoms onset. With the amount of water consumed daily, the odds ratio rose. Taking one glass of water not boiled had a matching odds ratio of 3; 2 glasses had a matching odds ratio of 12 (Roberts 2013). Furthermore, water from outside home taps and eating street vendor foods were also associated with the illness. The investigators applied multivariate logistic regression analysis.
Other hypotheses confirming information
Environmental studies and investigation of the water supply
This was done concurrently with the case-control study to identify factors that might have introduced pathogens into drinking water. The SES investigators learned that the city uses ground and surface water treated in four water treatment plants. Samotechnaya and Napornaya stations formed the northern treatment using Varzob river surface water. The southern treatment plants (South West and Kafefernigan stations) used groundwater (Robbins 2007).
Water from the two southern treatment plants was directly pumped from wells to holding tanks and then to the distribution system of the public without treatment. The basins for sedimentation at the stations had algae and silt, and the machines for dredging were broken. Furthermore, the sand filters had mud balls and displayed fouling with iron oxide, compromising the filtration process. The water had also not been regularly regulated since December, with half of the pumps stalled. This limited the city with a supply of water (Kiple 2008).
The turbidity and fecal coli forms test of the treated water from the treatment plants showed 150 nephelometric turbidity units and 132 colony-forming units per 100 milliliters at Napornaya station. Samotecnaya station had 70NTU and 118 CFU/100ml. Groundwater plants were free. From the household investigations on water samples, 97% and community taps had contaminated water with fecal coli forms of 175CFU/100ml (Emmeluth 2004).
Recommendations to prevent future outbreaks
Rudenstine & Galea (2012) observed that controlling and preventing future waterborne diseases and typhoid fever in Dushanbe requires many actions, such as:
- Improved protection of river Varzob watershed.
- Replacement or repair the water treatment plant equipment, such as sand filters, dredging machinery, and pumps.
- Training of staff of the water treatment plant thoroughly.
- Change of processes of water treatment.
- Procurement of coagulant and chlorine in adequate amounts.
- Replacement or treatment of old water distribution system
- Public education on water conservation to reduce wastage of water.
Discussion and conclusion
The best approach to achieve a healthy public water supply is to use multiple barriers to prevent contaminants from entering. The typhoid fever outbreak in Dushanbe was due to part of system failure. The contributing factors to Dushanbe water services include:
- Surface waters are chronically contaminated due to untreated waste discharge into rivers and flooding every spring.
- Inadequate processes of treatment.
- Water treatment plants disrepair.
- Frequent intermittent and low water pressure due to water pump failure, line breakages, and water wastage (Osler 1995).
Lessons learned and recommendations.
These problems attributed to the situation in Dushanbe include resource reduction devoted to water treatment plants maintenance, increasing repairs of the backlog, loss of trained maintenance personnel, and aging distribution pipes and treatment equipment. Therefore, steps should be taken to address and understand these problems.
Bibliography
Arnold Bf, & Colford Jm Jr. (2007), Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: a systematic review and meta-analysis, 76, 354-64. Accessed on July 16, 2013
Clasen, T., Schmidt, W.-P., Rabie, T., Roberts, I., & Cairncross, S. (2007), Interventions to improve water quality for preventing diarrhea: systematic review and meta-analysis, BRITISH MEDICAL JOURNAL. 782-785. Accessed on July 16, 2013
Tarr Pe, Kuppens L, Jones Tc, Ivanoff B, Aparin Pg, & Heymann Dl. (1999), Considerations regarding mass vaccination against typhoid fever as an adjunct to sanitation and public health measures: potential use in an epidemic in Tajikistan, The American Journal of Tropical Medicine and Hygiene. 61, 163-70. Accessed on July 16, 2013
Centers for Disease Control And Prevention (CDC). (1998), Epidemic typhoid fever–Dushanbe, Tajikistan, 1997, MMWR, Morbidity, and Mortality Weekly Report. 47, 752-6. Accessed on July 16, 2013
Mermin, J. H., Et Al. (1999), A Massive Epidemic of Multidrug-Resistant Typhoid Fever in Tajikistan Associated with Consumption of Municipal Water, The Journal of Infectious Diseases. 179, 1416-1422. Accessed on July 16, 2013
Hamilton, J., & Ivker, R. (1997), Threat of typhoid-fever epidemic hangs over Tajikistan. The Lancet. 349, 929-929.Accessed on July 16, 2013
Emmeluth, D. (2004), Typhoid fever, Philadelphia, Chelsea House Publishers.
Rudenstine, S., & Galea, S. (2012), The causes and behavioral consequences of disasters models informed by the global experience 1950-2005. New York, Springer. Retrieved on July 23, 2013, from
http://public.eblib.com/EBLPublic/PublicView.do?ptiID=884049.
Murdoch Da, Banatvaia N, Bone A, Shoismatulloev Bi, Ward Lr, & Threlfall Ej. (1998), Epidemic ciprofloxacin-resistant Salmonella typhi in Tajikistan, Lancet. 351.
Taylor Dn, Levine Mm, Kuppens L, & Ivanoff B. (1999), Why are typhoid vaccines not recommended for epidemic typhoid fever? The Journal of Infectious Diseases, 180, 2089-90.
Roberts, Leslie. (N.D.), Water and sanitation needs in complex humanitarian emergencies: 221.629, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins Bloomberg School of Public Health. Retrieved on July 23, 2013, from
http://www.intute.ac.uk/sciences/cgi-bin/fullrecord.pl?handle=20071209-172843.
(1997). Typhoid fever, Tajikistan, WEEKLY EPIDEMIOLOGICAL RECORD- WORLD HEALTH ORGANIZATION. 72, 70.
Robbins, P. (2007), Encyclopedia of environment and society, Thousand Oaks, Sage Publications. Retrieved on July 23, 2013, from
http://www.credoreference.com/book/sageenvsoc.
Asia-Pacific Symposium On Typhoid Fever, Pang, T., Koh, C. L., & Puthucheary, S. D. (1992), Typhoid fever: strategies for the ’90s: selected papers from the First Asia-Pacific Symposium on Typhoid Fever, Kuala Lumpur, Malaysia, October 1-3, 1991. Singapore, World Scientific.
Sarasombath, S., & Senawong, S. (1995), Second Asia-Pacific symposium on typhoid fever and another salmonellosis, SEAMEO Regional Tropical Medicine and Public Health Network, Bangkok.
Kiple, K. F. (2008), The Cambridge world history of human disease, Cambridge, Cambridge University Press. Retrieved on July 23, 2013, from
Osler, W. (1995), Studies in typhoid fever, Johns Hopkins Hospital Reports. 5, 6-9.
