Environmental Surveillance for Salmonella Typhi and its Association With Typhoid Fever Incidence in India and Malawi.
J Infect Dis
; 229(4): 979-987, 2024 Apr 12.
Article
en En
| MEDLINE
| ID: mdl-37775091
ABSTRACT
BACKGROUND:
Environmental surveillance (ES) for Salmonella Typhi potentially offers a low-cost tool to identify communities with a high burden of typhoid fever.METHODS:
We developed standardized protocols for typhoid ES, including sampling site selection, validation, characterization; grab or trap sample collection, concentration; and quantitative PCR targeting Salmonella genes (ttr, staG, and tviB) and a marker of human fecal contamination (HF183). ES was implemented over 12 months in a historically high typhoid fever incidence setting (Vellore, India) and a lower incidence setting (Blantyre, Malawi) during 2021-2022.RESULTS:
S. Typhi prevalence in ES samples was higher in Vellore compared with Blantyre; 39/520 (7.5%; 95% confidence interval [CI], 4.4%-12.4%) vs 11/533 (2.1%; 95% CI, 1.1%-4.0%) in grab and 79/517 (15.3%; 95% CI, 9.8%-23.0%) vs 23/594 (3.9%; 95% CI, 1.9%-7.9%) in trap samples. Detection was clustered by ES site and correlated with site catchment population in Vellore but not Blantyre. Incidence of culture-confirmed typhoid in local hospitals was low during the study and zero some months in Vellore despite S. Typhi detection in ES.CONCLUSIONS:
ES describes the prevalence and distribution of S. Typhi even in the absence of typhoid cases and could inform vaccine introduction. Expanded implementation and comparison with clinical and serological surveillance will further establish its public health utility.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fiebre Tifoidea
/
Vacunas Tifoides-Paratifoides
Tipo de estudio:
Guideline
/
Incidence_studies
/
Prognostic_studies
/
Risk_factors_studies
/
Screening_studies
Aspecto:
Patient_preference
Límite:
Humans
País/Región como asunto:
Africa
/
Asia
Idioma:
En
Revista:
J Infect Dis
Año:
2024
Tipo del documento:
Article
País de afiliación:
Reino Unido