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Chigwechokha P, Nyirenda RL, Dalitsani D, Namaumbo RL, Kazembe Y, Smith T, Holm RH. Vibrio cholerae and Salmonella Typhi culture-based wastewater or non-sewered sanitation surveillance in a resource-limited region. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:432-439. [PMID: 38177335 DOI: 10.1038/s41370-023-00632-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 12/02/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024]
Abstract
BACKGROUND In resource-limited regions, relying on individual clinical results to monitor community diseases is sometimes not possible. Establishing wastewater and non-sewered sanitation surveillance systems can offer opportunities to improve community health. OBJECTIVE We provide our experience of establishing a wastewater and non-sewered sanitation surveillance laboratory in Malawi, a resource-limited region, for Vibrio cholerae and Salmonella serotype Typhi. METHODS Three locations (inclusive of 8 discrete sample collection sites in total) in the Blantyre District were studied for nine weeks, from September 6 to November 1, 2022. Grab samples were collected weekly. We piloted locally available culture-based medical diagnostic methods for V. cholerae and S. Typhi in wastewater, followed by confirmation analysis of the isolates using reverse transcription polymerase chain reaction (RT-PCR). RESULTS Bacterial counts ranged from up to 106 colony-forming units/mL for V. cholerae and up to 107 colony-forming units/mL for S. Typhi. RT-PCR of the isolates showed that the available culture-based medical diagnostic methods were successful in detecting V. cholerae but were less accurate for S. Typhi in wastewater. IMPACT STATEMENT This experience serves as a catalyst for the development and validation of alternative wastewater surveillance analytical methods that are not dependent solely on RT-PCR. In this field trial conducted in Africa, new data-driven approaches were developed to promote early-level wastewater research and expand analysis options in resource-limited settings. Although culture-based methods are labor-intensive and have some limitations, we suggest initially leveraging the overlap with the locally available medical testing capacity for V. cholerae, whereas S. Typhi with RT-PCR may still be required. Wastewater analysis may be acceptable for V. cholerae and S. Typhi, which have a high degree of clinical case underreporting, fecal shedding, short incubation periods, and clear outbreak trends, predominantly in low- and middle-income countries.
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Affiliation(s)
- Petros Chigwechokha
- Department of Biological Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
| | - Ruth Lusungu Nyirenda
- Department of Biological Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
| | - Davie Dalitsani
- Department of Biological Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
| | - Ranken Lorvin Namaumbo
- Department of Biological Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
| | - Yohanny Kazembe
- Department of Biological Sciences, Malawi University of Science and Technology, P.O. Box 5196, Limbe, Malawi
| | - Ted Smith
- Christina Lee Brown Envirome Institute, School of Medicine, University of Louisville, 302 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA
| | - Rochelle H Holm
- Christina Lee Brown Envirome Institute, School of Medicine, University of Louisville, 302 E. Muhammad Ali Blvd., Louisville, KY, 40202, USA.
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Baig U, Mehdi SM, Iftikhar N. A pattern of antibiotic drug resistance of Salmonella Typhi and Salmonella Paratyphi among children with enteric fever in a tertiary care hospital in Lahore, Pakistan. Croat Med J 2023; 64:256-264. [PMID: 37654037 PMCID: PMC10509684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/10/2023] [Indexed: 09/02/2023] Open
Abstract
AIM To establish the pattern of antibiotic resistance and assess the frequency of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Salmonella Typhi and Salmonella Paratyphi among children with enteric fever. METHODS This cross-sectional study was carried out in the Department of Pediatrics, Sharif Medical City Hospital, Lahore, from July 2020 to January 2021. The study involved patients aged between 0 to 15 years who attended our outpatient department or were admitted to the ward with the suspicion of typhoid fever. A convenience sample of patients with blood cultures positive for S. Typhi and S. Paratyphi was enrolled. RESULTS Of the 105 participants, 70 (66.7%) were male. The mean age was 8.48±4.18 years, and the most affected age group was 6-10 years (n=46, 43.8%). Among the cultured organisms, 95 (90.5%) isolates were S. Typhi and 10 (9.5%) were S. Paratyphi A. Antibiotic resistance was highest against ampicillin (n=91, 86.7%), and all of the isolates were sensitive to imipenem and meropenem. Twenty-three (21.9%) cultured organisms were MDR and 54 (56.8%) were XDR. CONCLUSION An alarming antibiotic drug resistance pattern was observed among children with enteric fever in Lahore. The lowest resistance was noted for azithromycin, meropenem, and imipenem. Our findings warrant the immediate implementation of tailored antibiotic stewardship and infection control strategies.
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Affiliation(s)
- Usman Baig
- Baig, Department of Pediatrics, Sharif Medical City Hospital, Sharif Medical City Rd, off Raiwind Road, Jati Umra Lahore 55150, Punjab, Pakistan,
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Liu H, Wang S, Yang S, Luo SX, Jie J, Hua S, Peng L, Luo J, Song L, Li D. Characteristics of the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron BA.2 Subvariant in Jilin, China from March to May 2022. J Transl Int Med 2022; 10:349-358. [PMID: 36860638 PMCID: PMC9969560 DOI: 10.2478/jtim-2022-0054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background and Objectives In the midst of the pandemic, new coronavirus mutants continue to emerge; the most relevant variant worldwide is omicron. Here, patients who recovered from the disease living in Jilin Province were analyzed to identify factors affecting the severity of omicron infection and to provide insights into its spread and early indication. Methods In this study, 311 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were divided into two groups. Data on the patients' demographic characteristics and laboratory tests, including platelet count (PLT), neutrophil count (NE), C-reactive protein (CRP), serum creatinine (SCR), and neutrophil-to-lymphocyte ratio (NLR), were collected. The biomarkers for moderate and severe coronavirus disease 2019 (COVID-19) and factors affecting the incubation period and time to subsequent negative nucleic acid amplification test (NAAT) were also investigated. Results Age, gender, vaccination, hypertension, stroke, chronic obstructive pulmonary disease (COPD)/chronic bronchitis/asthma, and some laboratory tests were statistically different between the two groups. In the receiver operating characteristic (ROC) analysis, PLT and CRP had higher area under the ROC curve values. In the multivariate analysis, age, hypertension, COPD/chronic bronchitis/asthma, and CRP were correlated with moderate and severe COVID-19. Moreover, age was correlated with longer incubation. In the Kaplan-Meier curve analysis, gender (male), CRP, and NLR were associated with longer time to subsequent negative NAAT. Conclusions Older patients with hypertension and lung diseases were likely to have moderate or severe COVID-19, and younger patients might have a shorter incubation. A male patient with high CRP and NLR levels might take more time to turn back negative in the NAAT.
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Affiliation(s)
- Han Liu
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Shuai Wang
- Department of Vascular Surgery, General Surgery Center, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Siqi Yang
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Sean X. Luo
- Department of Vascular Surgery, General Surgery Center, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Jing Jie
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Shucheng Hua
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Liping Peng
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Jingjing Luo
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Lei Song
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
| | - Dan Li
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun130000, Jilin Province, China
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Nabarro LE, McCann N, Herdman MT, Dugan C, Ladhani S, Patel D, Morris-Jones S, Balasegaram S, Heyderman RS, Brown M, Parry CM, Godbole G. British Infection Association Guidelines for the Diagnosis and Management of Enteric Fever in England. J Infect 2022; 84:469-489. [PMID: 35038438 DOI: 10.1016/j.jinf.2022.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/10/2021] [Accepted: 01/05/2022] [Indexed: 11/25/2022]
Abstract
Enteric fever (EF) is an infection caused by the bacteria called Salmonella Typhi or Paratyphi. Infection is acquired through swallowing contaminated food or water. Most EF in England occurs in people returning from South Asia and other places where EF is common; catching EF in England is rare. The main symptom is fever, but stomach pain, diarrhoea, muscle aches, rash and other symptoms may occur. EF is diagnosed by culturing the bacteria from blood and/or stool in a microbiology laboratory. EF usually responds well to antibiotic treatment. Depending on how unwell the individual is, antibiotics may be administered by mouth or by injection. Over the past several years, there has been an overall increase in resistance to antibiotics used to treat enteric fever, in all endemic areas. Additionally, since 2016, there has been an ongoing outbreak of drug-resistant EF in Pakistan. This infection is called extensively drug-resistant, or XDR, EF and only responds to a limited number of antibiotics. Occasionally individuals develop complications of EF including confusion, bleeding, a hole in the gut or an infection of the bones or elsewhere. Some people may continue to carry the bacteria in their stool for a longtime following treatment for the initial illness. These people may need treatment with a longer course of antibiotics to eradicate infection. Travellers can reduce their risk of acquiring EF by following safe food and water practices and by receiving the vaccine at least a few weeks before travel. These guidelines aim to help doctors do the correct tests and treat patients for enteric fever in England but may also be useful to doctors and public health professionals in other similar countries.
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Affiliation(s)
- L E Nabarro
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK; United Kingdom Health Security Agency, UK; St George's University Hospitals NHS Foundation Trust, London, UK; British Infection Association, UK
| | - N McCann
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK
| | | | - C Dugan
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK
| | - S Ladhani
- United Kingdom Health Security Agency, UK; Paediatric Infectious Diseases Research Group, St George's University, London, UK
| | - D Patel
- National Travel Health Network and Centre (NaTHNaC), UK
| | - S Morris-Jones
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK
| | | | - R S Heyderman
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK; Research Department of Infection, Division of Infection and Immunity, University College London, London, UK
| | - M Brown
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK; Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - C M Parry
- Liverpool School of Tropical Medicine, Liverpool, UK; Alder Hey Hospital and Liverpool University Hospitals, Liverpool, UK; Centre for Tropical Medicine and Global Health, University of Oxford, UK
| | - G Godbole
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK; United Kingdom Health Security Agency, UK; British Infection Association, UK.
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Nili S, Khanjani N, Bakhtiari B, Jahani Y, Dalaei H. The effect of meteorological variables on salmonellosis incidence in Kermanshah, West of Iran: a generalized linear model with negative binomial approach. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2021; 19:1171-1177. [PMID: 34150303 PMCID: PMC8172766 DOI: 10.1007/s40201-021-00684-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
PURPOSE Salmonella is one of the main causes of gastroenteritis, and its incidence may be affected by meteorological variables. This is the first study about the effect of climatic factors on salmonella incidence in Kermanshah, Iran. METHODS Data about salmonellosis cases in Kermanshah were inquired from Center for Communicable Disease Control, at the Ministry of Health and Medical Education of Iran, for the 2008 to 2018 time-frame. Meteorological variables including maximum, minimum and mean of temperature and humidity, sunshine hours and rainfall were inquired for the same time frame. Negative binomial generalized linear models (GLM) were used to assess the effect of meteorological variables on the weekly incidence of salmonellosis. RESULTS During the years under study, 569 confirmed cases were registered in Kermanshah province. Study results showed a 3 % increase in salmonellosis incidence, after 1 % increase in minimum humidity in the week before (incidence rate ratio (IRR): 1.03; 95 % confidence interval (CI):1.02-1.05) and also a 4 % increase in incidence for 1 °C increase in mean temperature in the same week (IRR: 1.04; 95 % CI:1.02-1.06). CONCLUSIONS Increase in minimum humidity and mean temperature may have a role in increasing the incidence of salmonellosis in Iran.
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Affiliation(s)
- Sairan Nili
- Department of Public Health, Faculty of Health, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Narges Khanjani
- Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
- Department of Epidemiology and Biostatistics, School of Public Health, Kerman University of Medical Sciences, 76169-13555 Kerman, Iran
| | - Bahram Bakhtiari
- Water Engineering Department, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Yunes Jahani
- Modeling in Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran
| | - Hamideh Dalaei
- Research Deputy of Iranian Meteorological Organization (IRIMO), Tehran, Iran
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Quesada JA, López-Pineda A, Gil-Guillén VF, Arriero-Marín JM, Gutiérrez F, Carratala-Munuera C. [Incubation period of COVID-19: A systematic review and meta-analysis]. Rev Clin Esp 2021; 221:109-117. [PMID: 33024342 PMCID: PMC7528969 DOI: 10.1016/j.rce.2020.08.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND OBJECTIVE The incubation period of COVID-19 helps to determine the optimal duration of the quarantine and inform predictive models of incidence curves. Several emerging studies have produced varying results; this systematic review aims to provide a more accurate estimate of the incubation period of COVID-19. METHODS For this systematic review, a literature search was conducted using Pubmed, Scopus/EMBASE, and the Cochrane Library databases, covering all observational and experimental studies reporting the incubation period and published from 1 January 2020 to 21 March 2020.We estimated the mean and 95th percentile of the incubation period using meta-analysis, taking into account between-study heterogeneity, and the analysis with moderator variables. RESULTS We included seven studies (n = 792) in the meta-analysis. The heterogeneity (I2 83.0%, p < 0.001) was significantly decreased when we included the study quality and the statistical model used as moderator variables (I2 15%). The mean incubation period ranged from 5.6 (95% CI: 5.2 to 6.0) to 6.7 days (95% CI: 6.0 to 7.4) according to the statistical model. The 95th percentile was 12.5 days when the mean age of patients was 60 years, increasing 1 day for every 10 years. CONCLUSION Based on the published data reporting the incubation period of COVID-19, the mean time between exposure and onset of clinical symptoms depended on the statistical model used, and the 95th percentile depended on the mean age of the patients. It is advisable to record sex and age when collecting data in order to analyze possible differential patterns.
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Affiliation(s)
- J A Quesada
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, España
| | - A López-Pineda
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, España
| | - V F Gil-Guillén
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, España
| | - J M Arriero-Marín
- Departamento de Neumología, Universidad Hospital de San Juan de Alicante, San Juan de Alicante, España
| | - F Gutiérrez
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, España
- Departamento de Enfermedades Infecciosas, Universidad Hospital de Elche, Elche, España
| | - C Carratala-Munuera
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, España
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Quesada JA, López-Pineda A, Gil-Guillén VF, Arriero-Marín JM, Gutiérrez F, Carratala-Munuera C. Incubation period of COVID-19: A systematic review and meta-analysis. Rev Clin Esp 2021; 221:109-117. [PMID: 33998486 PMCID: PMC7698828 DOI: 10.1016/j.rceng.2020.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/17/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND OBJECTIVE The incubation period of COVID-19 helps to determine the optimal duration of the quarantine and inform predictive models of incidence curves. Several emerging studies have produced varying results; this systematic review aims to provide a more accurate estimate of the incubation period of COVID-19. METHODS For this systematic review, a literature search was conducted using Pubmed, Scopus/EMBASE, and the Cochrane Library databases, covering all observational and experimental studies reporting the incubation period and published from 1 January 2020 to 21 March 2020.We estimated the mean and 95th percentile of the incubation period using meta-analysis, taking into account between-study heterogeneity, and the analysis with moderator variables. RESULTS We included seven studies (n=792) in the meta-analysis. The heterogeneity (I2 83.0%, p<0.001) was significantly decreased when we included the study quality and the statistical model used as moderator variables (I2 15%). The mean incubation period ranged from 5.6 (95% CI: 5.2-6.0) to 6.7 days (95% CI: 6.0-7.4) according to the statistical model. The 95th percentile was 12.5 days when the mean age of patients was 60 years, increasing 1 day for every 10 years. CONCLUSION Based on the published data reporting the incubation period of COVID-19, the mean time between exposure and onset of clinical symptoms depended on the statistical model used, and the 95th percentile depended on the mean age of the patients. It is advisable to record sex and age when collecting data in order to analyze possible differential patterns.
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Affiliation(s)
- J A Quesada
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain
| | - A López-Pineda
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain.
| | - V F Gil-Guillén
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain
| | - J M Arriero-Marín
- Departamento de Neumología, Universidad Hospital de San Juan de Alicante, San Juan de Alicante, Spain
| | - F Gutiérrez
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain; Departamento de Enfermedades Infecciosas, Universidad Hospital de Elche, Elche, Spain
| | - C Carratala-Munuera
- Departamento de Medicina Clínica, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain
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Dhingra D, Marathe SA, Sharma N, Marathe A, Chakravortty D. Modeling the immune response to Salmonella during typhoid. Int Immunol 2021; 33:281-298. [PMID: 33406267 DOI: 10.1093/intimm/dxab003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/05/2021] [Indexed: 11/13/2022] Open
Abstract
Several facets of the host immune response to Salmonella infection have been studied independently at great depths to understand the progress and pathogenesis of Salmonella infection. The circumstances under which a Salmonella-infected individual succumbs to an active disease, evolves as a persister or clears the infection are not understood in detail. We have adopted a system-level approach to develop a continuous-time mechanistic model. We considered key interactions of the immune system state variables with Salmonella in the mesenteric lymph node to determine the final disease outcome deterministically and exclusively temporally. The model accurately predicts the disease outcomes and immune response trajectories operational during typhoid. The results of the simulation confirm the role of anti-inflammatory (M2) macrophages as a site for persistence and relapsing infection. Global sensitivity analysis highlights the importance of both bacterial and host attributes in influencing the disease outcome. It also illustrates the importance of robust phagocytic and anti-microbial potential of M1 macrophages and dendritic cells (DCs) in controlling the disease. Finally, we propose therapeutic strategies for both antibiotic-sensitive and antibiotic-resistant strains (such as IFN-γ therapy, DC transfer and phagocytic potential stimulation). We also suggest prevention strategies such as improving the humoral response and macrophage carrying capacity, which could complement current vaccination schemes for enhanced efficiency.
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Affiliation(s)
- Divy Dhingra
- Department of Mechanical Engineering, Birla Institute of Technology & Science, Pilani, Rajasthan, India
| | - Sandhya Amol Marathe
- Department of Biological Sciences, Birla Institute of Technology & Science, Pilani, Rajasthan, India
| | - Nandita Sharma
- Department of Biological Sciences, Birla Institute of Technology & Science, Pilani, Rajasthan, India
| | - Amol Marathe
- Department of Mechanical Engineering, Birla Institute of Technology & Science, Pilani, Rajasthan, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, India
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Quantitative Assessment of an Artificial Neural Network for the Variation in Immunity to Salmonella Infection Among Sudanese and Chinese Populations and the Relationship Between HLA-DQB1 and Antibody: A Preliminary Study. Jundishapur J Microbiol 2020. [DOI: 10.5812/jjm.99379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Awofisayo-Okuyelu A, Pratt A, McCarthy N, Hall I. Within-host mathematical modelling of the incubation period of Salmonella Typhi. ROYAL SOCIETY OPEN SCIENCE 2019; 6:182143. [PMID: 31598273 PMCID: PMC6774937 DOI: 10.1098/rsos.182143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 08/06/2019] [Indexed: 06/10/2023]
Abstract
Mechanistic mathematical models are often employed to understand the dynamics of infectious diseases within a population or within a host. They provide estimates that may not be otherwise available. We have developed a within-host mathematical model in order to understand how the pathophysiology of Salmonella Typhi contributes to its incubation period. The model describes the process of infection from ingestion to the onset of clinical illness using a set of ordinary differential equations. The model was parametrized using estimated values from human and mouse experimental studies and the incubation period was estimated as 9.6 days. A sensitivity analysis was also conducted to identify the parameters that most affect the derived incubation period. The migration of bacteria to the caecal lymph node was observed as a major bottle neck for infection. The sensitivity analysis indicated the growth rate of bacteria in late phase systemic infection and the net population of bacteria in the colon as parameters that most influence the incubation period. We have shown in this study how mathematical models aid in the understanding of biological processes and can be used in estimating parameters of infectious diseases.
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Affiliation(s)
- Adedoyin Awofisayo-Okuyelu
- National Institute of Health Research Health Protection Research Unit in Gastrointestinal Infections, University of Oxford, Oxford, UK
- Department of Zoology, University of Oxford, Oxford, UK
| | - Adrian Pratt
- Emergency Response Department Science and Technology (ERD S&T), Health Protection Directorate, Public Health England, Porton Down, UK
| | - Noel McCarthy
- National Institute of Health Research Health Protection Research Unit in Gastrointestinal Infections, University of Oxford, Oxford, UK
- Department of Zoology, University of Oxford, Oxford, UK
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Ian Hall
- School of Mathematics, University of Manchester, Manchester, UK
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Differences in Antibodies Against Blood Group, HBV, and Salmonella Regarding Protein Content, Activity, and Affinity in Black and Yellow Healthy Individuals. Jundishapur J Microbiol 2019. [DOI: 10.5812/jjm.94687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Moser-van der Geest N, Schibli A, Huber LC. [CME: Typhoid Fever - Clinical Manifestation, Diagnosis, Therapy and Prevention]. PRAXIS 2019; 108:937-943. [PMID: 31662103 DOI: 10.1024/1661-8157/a003319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
CME: Typhoid Fever - Clinical Manifestation, Diagnosis, Therapy and Prevention Abstract. Thypoid fever is rare in Western countries. It is, however, among the most common etiologies for febrile illness in the traveller returning from tropical areas (especially South(east) Asia and Sub-Saharan Africa). There are several signs that have been described as classical findings in typhoid fever: i) febrile temperatures with relative bradycardia, ii) eosinopenia, iii) slow defervescence, and iv) systemic manifestations (e.g. hepatitis). Diagnosis is confirmed by positive blood cultures. Pretravel vaccination and safe food and water practices can prevent typhoid fever.
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Affiliation(s)
| | - Adrian Schibli
- Abteilung für Infektiologie, Departement für Innere Medizin, Stadtspital Triemli
| | - Lars C Huber
- Klinik für Innere Medizin, Departement für Innere Medizin, Stadtspital Triemli
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