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. 2020 Dec 1;71(Suppl 3):S205-S213.
doi: 10.1093/cid/ciaa1319.

Spatial Heterogeneity of Enteric Fever in 2 Diverse Communities in Nepal

Dipesh Tamrakar  1 , Krista Vaidya  1 , Alexander T Yu  2 , Kristen Aiemjoy  2 , Shiva Ram Naga  1 , Yanjia Cao  2 , Caryn Bern  3 , Rajeev Shrestha  1 , Biraj M Karmacharya  1 , Sailesh Pradhan  4 , Farah Naz Qamar  5 , Samir Saha  6 , Kashmira Date  7 , Ashley T Longley  7   8 , Caitlin Hemlock  9 , Stephen Luby  2 , Denise O Garrett  9 , Isaac I Bogoch  10 , Jason R Andrews  2
Affiliations

Spatial Heterogeneity of Enteric Fever in 2 Diverse Communities in Nepal

Dipesh Tamrakar et al. Clin Infect Dis. .

Abstract

Background: Typhoid fever is endemic in the urban Kathmandu Valley of Nepal; however, there have been no population-based studies of typhoid outside of this community in the past 3 decades. Whether typhoid immunization should be prioritized in periurban and rural communities has been unclear.

Methods: We performed population-based surveillance for enteric fever in 1 urban catchment (Kathmandu) and 1 periurban and rural catchment (Kavrepalanchok) as part of the Surveillance for Enteric Fever in Asia Project (SEAP). We recruited individuals presenting to outpatient and emergency departments at 2 study hospitals with suspected enteric fever and performed blood cultures. Additionally, we conducted a household survey in each catchment area to characterize care seeking for febrile illness. We evaluated spatial heterogeneity in febrile illness, care seeking, and enteric fever incidence.

Results: Between September 2016 and September 2019, we enrolled 5736 participants with suspected enteric fever at 2 study hospitals. Among these, 304 (5.3%) were culture positive for Salmonella Typhi (249 [81.9%]) or Paratyphi A (55 [18.1%]). Adjusted typhoid incidence in Kathmandu was 484 per 100 000 person-years and in Kavrepalanchok was 615 per 100 000 person-years. While all geographic areas for which estimates could be made had incidence >200 per 100 000 person-years, we observed spatial heterogeneity with up to 10-fold variation in incidence between communities.

Conclusions: In urban, periurban, and rural communities in and around Kathmandu, we measured a high but heterogenous incidence of typhoid. These findings provide some support for the introduction of conjugate vaccines in Nepal, including outside urban areas, alongside other measures to prevent enteric fever.

Keywords: Salmonella; Nepal; enteric fever; geospatial; typhoid.

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Figures

Figure 1.
Figure 1.
Population density in the Kathmandu wards and Kavrepalanchok municipalities comprising the study catchment area. Yellow crosses denote the location of study surveillance hospitals. Abbreviation: SEAP, Surveillance for Enteric Fever in Asia Project.
Figure 2.
Figure 2.
Proportion of individuals with fever in the past 8 weeks (top) and hospitalized for fever in the past year (bottom) for Kathmandu and Kavrepalanchok. Yellow crosses denote the location of study surveillance hospitals.
Figure 3.
Figure 3.
Proportion of individuals with fever in past 8 weeks (top) or hospitalized in past month (bottom) who sought care at the study hospitals in Kathmandu and Kavrepalanchok. Yellow crosses denote the location of study surveillance hospitals.
Figure 4.
Figure 4.
Probability of seeking care at study site as a function of road distance between household and the study site for Kathmandu (top) and Kavrepalanchok (bottom).
Figure 5.
Figure 5.
Incidence (cases per 100 000 person-years) of typhoid (A) and paratyphoid (B) by ward in Kathmandu and by municipality in Kavrepalanchok. Yellow crosses denote the location of study surveillance hospitals. Abbreviation: SEAP, Surveillance for Enteric Fever in Asia Project.
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References

    1. Andrews JR, Harris JB, Ryan ET. Typhoid fever, paratyphoid fever, and typhoidal fevers. In: Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA: Elsevier, 2020:1365– 79.e3.
    1. GBD 2017 Typhoid and Paratyphoid Collaborators. The global burden of typhoid and paratyphoid fevers: a systematic analysis for the Global Burden of Disease Study 2017. Lancet Infect Dis 2019; 19:369–81. - PMC - PubMed
    1. World Health Organization. Typhoid vaccines: WHO position paper—March 2018. Wkly Epidemiol Rec 2018; 93:153–72.
    1. Karkey A, Arjyal A, Anders KL, et al. The burden and characteristics of enteric fever at a healthcare facility in a densely populated area of Kathmandu. PLoS One 2010; 5:e13988. - PMC - PubMed
    1. Zellweger RM, Basnyat B, Shrestha P, et al. A 23-year retrospective investigation of Salmonella Typhi and Salmonella Paratyphi isolated in a tertiary Kathmandu hospital. PLoS Negl Trop Dis 2017; 11:e0006051. - PMC - PubMed

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