Risk factors for typhoid fever in an endemic setting, Karachi, Pakistan (original) (raw)
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The American Journal of Tropical Medicine and Hygiene, 2022
ABSTRACT. Typhoid fever is endemic in Pakistan, with high annual incidence rates. An outbreak of extensively drug-resistant typhoid fever that first started in the Hyderabad district of Sindh province in November 2016 immediately spread to the whole province. We conducted an age-matched case–control study to assess the risk factors of typhoid fever in an outbreak setting of Lyari Town, Karachi. We enrolled 82 patients with blood culture-confirmed Salmonella typhi between August 2019 to December 2019, 82 age-matched hospital and 164 age-matched community control subjects. In a matched conditional logistic regression model, consumption of meals outside the home more than once per month was associated significantly with developing culture-confirmed typhoid fever compared with no consumption of food outside the home (odds ratio, 4.11). Hygiene of the environment in which food is prepared, practices of adult food handlers, access to clean water, and food legislation play significant role...
Risk factors associated with typhoid fever in children aged 2-16 years in Karachi, Pakistan
Epidemiology and Infection, 2012
We analysed the data from the control group in a typhoid vaccine trial in Karachi to assess the differences in individual-, household-and cluster-level characteristics for developing typhoid fever. The annual incidence of typhoid in children aged 2-16 years in the control arm of the vaccine trial was 151/100 000 population. After adjustment, the risk of typhoid was lower with increasing age [risk ratio (RR) 0. 89, 95 % confidence interval (CI) 0. 83-0. 95], was higher with an increase in population density (RR 1. 13, 95% CI 1. 05-1. 21) and was lower in the households using a safe drinking-water source (RR 0. 63, 95% CI 0. 41-0. 99). Typhoid fever affects younger children living in areas of high population density and lack of access to safe water in Pakistan. A combination of environmental and biological interventions is required to prevent the continued epidemiological and economic impact of typhoid fever in high-risk areas of Pakistan.
Risk factors associated with typhoid fever among children 2 – 16 years of age in Karachi, Pakistan
Epidemiology and Infection
We analysed the data from the control group in a typhoid vaccine trial in Karachi to assess the differences in individual-, household-and cluster-level characteristics for developing typhoid fever. The annual incidence of typhoid in children aged 2-16 years in the control arm of the vaccine trial was 151/100 000 population. After adjustment, the risk of typhoid was lower with increasing age [risk ratio (RR) 0 . 89, 95 % confidence interval (CI) 0 . 83-0 . 95], was higher with an increase in population density (RR 1 . 13, 95% CI 1 . 05-1 . 21) and was lower in the households using a safe drinking-water source (RR 0 . 63, 95% CI 0 . 41-0 . 99). Typhoid fever affects younger children living in areas of high population density and lack of access to safe water in Pakistan. A combination of environmental and biological interventions is required to prevent the continued epidemiological and economic impact of typhoid fever in high-risk areas of Pakistan.
Risk factors for typhoid fever among adult patients in Diyarbakir, Turkey
Epidemiology and Infection, 2006
We conducted a case-control study to assess risk factors for typhoid fever in Diyarbakir, Turkey, a region where transmission of Salmonella typhi is endemic. We prospectively identified febrile patients from Diyarbakir and the surrounding area who were admitted to hospital. Cases were defined as patients who had S. typhi isolated from at least one blood culture. Sixty-four cases with blood culture-confirmed S. typhi were identified between May 2001 and May 2003. In total, 128 age-and sex-matched controls selected from neighbourhoods as cases were enrolled. We hypothesized that consumption of raw vegetables contaminated with sewage would be associated with an increased risk of typhoid fever. Conditional logistic regression modelling revealed that living in a crowded household (OR 3 . 31, 95% CI 1 . 58-6 . 92, P=0 . 002), eating cig kofte (a traditional raw food) (OR 5 . 29, 95 % CI 2 . 20-12 . 69, P=0 . 000) and lettuce salad (OR 3 . 55, 95 % CI 1 . 52-8 . 28, P=0 . 003) in the 15 days prior to symptoms onset was independently associated with typhoid fever. We conclude that living in a crowded household and consumption of raw vegetables outside the home increase the risk of typhoid fever in this region.
RISK FACTORS OF TYPHOID FEVER AMONGST PATIENTS IN THE ALLAHABAD REGION, INDIA
252 blood samples collected from patients of different localities of Allahabad region were found to be positive for typhoid fever when tested by Widal test. The causative agent Salmonella species were cultured from the blood samples and then were identified by using standard procedures. The isolates were identified as S. typhi, S. paratyphi A, S. typhimurium and S. bongori. Age, socio-economic status and seasonal variations were identified as significant risk factors associated with incidence of Salmonella infection. Blood samples were collected from both males and females belonging to the age groups from ˂1 to 50 years where the infection rate of typhoid fever was found to be higher among children. Socio-economic strata showed difference in incidence of Salmonella species with the low category showed highest number of isolates. Peak period of typhoid fever was found in June while a lower peak was noted in the month of November.
Impact of Safe Water and Improved Sanitation on Incidence/Prevalence of Typhoid Fever Globally
Typhoid fever is a systemic infection caused by the bacterium salmonella typhi. It occurs worldwide and more in developing countries. This study is a review of existing journals on typhoid fever is aimed to determine whether safe water usage or consumption and improved sanitation had an impact on the incidence/prevalence of typhoid fever globally. A literature search is carried out reviewing current and existing journals on typhoid fever. From the view, it was noted in most of the articles by various authors that safe water usage and improved sanitation impacted on incidence and prevalence of typhoid fever. It is however recommended that with implementation of various public health strategies on safe water, improved sanitation and personal hygiene there will be a reduction in the incidence of typhoid fever in our environment. Vacuration program on Typhoid should be stepped to further curb the high mortality rate from this water borne disease.
BMC Public Health, 2009
Background: In April 2007, a slum of South Dumdum municipality, West Bengal reported an increase in fever cases. We investigated to identify the agent, the source and to propose recommendations. Methods: We defined a suspected case of typhoid fever as occurrence of fever for ≥ one week among residents of ward 1 of South Dumdum during February-May 2007. We searched for suspected cases in health care facilities and collected blood specimens. We described the outbreak by time, place and person. We compared probable cases (Widal positive >= 1:80) with neighbourhood-matched controls. We assessed the environment and collected water specimens. Results: We identified 103 suspected cases (Attack rate: 74/10,000, highest among 5-14 years old group, no deaths). Salmonella (enterica) Typhi was isolated from one of four blood specimens and 65 of 103 sera were >= 1:80 Widal positive. The outbreak started on 13 February, peaked twice during the last week of March and second week of April and lasted till 27 April. Suspected cases clustered around three public taps. Among 65 probable cases and 65 controls, eating milk products from a sweet shop (Matched odds ratio [MOR]: 6.2, 95% confidence interval [CI]: 2.4-16, population attributable fraction [PAF]: 53%) and drinking piped water (MOR: 7.3, 95% CI: 2.5-21, PAF-52%) were associated with illness. The sweet shop food handler suffered from typhoid in January. The pipelines of intermittent non-chlorinated water supply ran next to an open drain connected with sewerage system and water specimens showed faecal contamination. Conclusion: The investigation suggested that an initial foodborne outbreak of typhoid led to the contamination of the water supply resulting in a secondary, waterborne wave. We educated the food handler, repaired the pipelines and ensured chlorination of the water.
The American Journal of Tropical Medicine and Hygiene, 2020
Typhoid fever transmission occurs through ingestion of food or water contaminated with Salmonella Typhi, and case-control studies are often conducted to identify outbreak sources and transmission vehicles. However, there is no current summary of the associations among water, sanitation, and hygiene (WASH); and food exposures and typhoid from case-control studies. We conducted a systematic review and meta-analysis of case-control studies to evaluate the associations among typhoid fever and predicted WASH or food exposure risk factors (13), and protective factors (7). Overall, 19 manuscripts describing 22 case-control studies were included. Two studies were characterized as having low risk of bias, one as medium risk, and 19 as high risk. In total, nine of 13 predicted risk factors were associated with increased odds of typhoid (odds ratio [OR] = 1.4-2.4, I 2 = 30.5-74.8%.), whereas five of seven predicted protective factors were associated with lower odds of typhoid (OR = 0.52-0.73, I 2 = 38.7-84.3%). In five types of sensitivity analyses, two (8%) of 26 summary associations changed significance from the original analysis. Results highlight the following: the importance of household hygiene transmission pathways, the need for further research around appropriate food interventions and the risk of consuming specific foods and beverages outside the home, and the absence of any observed association between sanitation exposures and typhoid fever. We recommend that typhoid interventions focus on interrupting household transmission routes and that future studies provide more detailed information about WASH and food exposures to inform better targeted interventions.
Journal of Infection and Public Health, 2008
Typhoid fever remains a major public health problem in developing countries such as Pakistan. A great majority of cases occur in children living in poor sanitary conditions in squatter settlements in large cities. We conducted a case-control study to identify risk factor for typhoid fever in children under the age of 16 years residing in squatter settlements of Karachi. We enrolled 88 typhoid fever patients, diagnosed by positive blood culture or Typhidot ® test, between June 1999 and December 2001. Simultaneously, we enrolled 165 age-matched neighborhood controls. Multivariate analysis done through conditional binary logistic regression analysis technique showed that increasing number of persons in the household (odds ratio [OR] = 1.9; 95% confidence interval [CI] 1.2-3.1), non-availability of soap near hand washing facility (OR = 2.6; 95% CI 1.1-6.3), non-use of medicated soap (OR = 11.2; 95% CI 1.3-97.6) and lack of awareness about contact with a known case of typhoid fever (OR = 3.7; 95% CI 1.6-8.4) were independent risk factors of the disease. Health education with emphasis on hand washing may help decrease the burden of typhoid fever in developing countries.
Journal of Health, Population and Nutrition, 2015
Background: Typhoid fever is the persistent cause of morbidity worldwide. Salmonella enterica serovar's carriers among food handlers have the potential to disseminate this infection on large scale in the community. The purpose of this study was to determine the prevalence of typhoidal S. enterica serovars among food handlers of Karachi. Methods: This cross-sectional study was conducted in Karachi metropolis. A total of 220 food handlers were recruited on the basis of inclusion criteria from famous food streets of randomly selected five towns of Karachi. Three consecutive stool samples were collected from each food handler in Carry Blair transport media. Culture, biochemical identification, serotyping, and antimicrobial susceptibility tests for S. enterica serovars were done. Results: Out of 220 food handlers, 209 consented to participate, and among them, 19 (9.1 %) were positive for S. enterica serovars. Serotyping of these isolates showed that 9 (4.3 %) were typhoidal S. serovars while 10 (4.7 %) were non-typhoidal S. serovars. Of the typhoidal S. serovars, 7 were S. enterica serovar Typhi and 1 each of S. enterica serovar Paratyphi A and B. The resistance pattern of these isolates showed that 77.7 % were resistant to ampicillin and 11.1 % to cotrimoxazole. All typhoidal S. enterica serovar isolates were sensitive to chloramphenicol, ceftriaxone, cefixime, nalidixic acid, and ofloxacin. Conclusions: Carrier rate of typhoidal S. enterica serovars in food handlers working in different food streets of Karachi is very high. These food handlers might be contributing to the high endemicity of typhoid fever in Karachi, Pakistan.