Risk Factors of Typhoid Infection in the Indonesian Archipelago.
BACKGROUND
Knowledge of risk factors and their relative importance in different settings is essential to develop effective health education material for the prevention of typhoid. In this study, we examine the effect of household level and individual behavioural risk factors on the risk of typhoid in three Indonesian islands (Sulawesi, Kalimantan and Papua) in the Eastern Indonesian archipelago encompassing rural, peri-urban and urban areas.


METHODS
We enrolled 933 patients above 10 years of age in a health facility-based case-control study between June 2010 and June 2011. Individuals suspected of typhoid were tested using the typhoid IgM lateral flow assay for the serodiagnosis of typhoid fever followed by blood culture testing. Cases and controls were defined post-recruitment: cases were individuals with a culture or serology positive result (n = 449); controls were individuals negative to both serology and culture, with or without a diagnosis other than typhoid (n = 484). Logistic regression was used to examine the effect of household level and individual level behavioural risk factors and we calculated the population attributable fraction (PAF) of removing each risk significant independent behavioural risk factor.


RESULTS
Washing hands at critical moments of the day and washing hands with soap were strong independent protective factors for typhoid (OR = 0.38 95% CI 0.25 to 0.58 for each unit increase in hand washing frequency score with values between 0 = Never and 3 = Always; OR = 3.16 95% CI = 2.09 to 4.79 comparing washing hands with soap sometimes/never vs. often). These effects were independent of levels of access to water and sanitation. Up to two thirds of cases could be prevented by compliance to these practices (hand washing PAF = 66.8 95% CI 61.4 to 71.5; use of soap PAF = 61.9 95%CI 56.7 to 66.5). Eating food out in food stalls or restaurant was an important risk factor (OR = 6.9 95%CI 4.41 to 10.8 for every unit increase in frequency score).


CONCLUSIONS
Major gains could potentially be achieved in reducing the incidence of typhoid by ensuring adherence to adequate hand-washing practices alone. This confirms that there is a pivotal role for 'software' related interventions to encourage behavior change and create demand for goods and services, alongside development of water and sanitation infrastructure.
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Sandra
S
Alba
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Mirjam I
MI
Bakker
Department of Medical Microbiology, Molecular Biology and Immunology Laboratory, Faculty of Medicine, Hasanuddin University, Makassar, South-Sulawesi, Indonesia.
Mochammad
M
Hatta
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Pauline F D
PF
Scheelbeek
Department of Medical Microbiology, Molecular Biology and Immunology Laboratory, Faculty of Medicine, Hasanuddin University, Makassar, South-Sulawesi, Indonesia.
Ressy
R
Dwiyanti
Department of Medical Microbiology, Molecular Biology and Immunology Laboratory, Faculty of Medicine, Hasanuddin University, Makassar, South-Sulawesi, Indonesia.
Romi
R
Usman
Department of Medical Microbiology, Molecular Biology and Immunology Laboratory, Faculty of Medicine, Hasanuddin University, Makassar, South-Sulawesi, Indonesia.
Andi R
AR
Sultan
Department of Medical Microbiology, Molecular Biology and Immunology Laboratory, Faculty of Medicine, Hasanuddin University, Makassar, South-Sulawesi, Indonesia.
Muhammad
M
Sabir
Department Microbiology, Faculty of Medicine, Mulawarman University, Samarinda, East-Kalimantan, Indonesia.
Nataniel
N
Tandirogang
Department Microbiology, Faculty of Medicine, Mulawarman University, Samarinda, East-Kalimantan, Indonesia.
Masyhudi
M
Amir
Department Microbiology, Faculty of Medicine, Mulawarman University, Samarinda, East-Kalimantan, Indonesia.
Yadi
Y
Yasir
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Rob
R
Pastoor
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Stella
S
van Beers
KIT Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
Henk L
HL
Smits
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006235:Hand Disinfection; D006801:Humans; D015994:Incidence; D007214:Indonesia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data*; D012307:Risk Factors; D012485:Salmonella typhi / Q000302:isolation & purification*; D012499:Sanitation; D014435:Typhoid Fever / Q000453:epidemiology*; D055815:Young Adult