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Gomes MC, Padilha EKA, Diniz GRA, Gomes EC, da Silva Santos-Júnior PF, Zhan P, da Siva-Júnior EF. Multi-target Compounds against Trypanosomatid Parasites and Mycobacterium tuberculosis. Curr Drug Targets 2024; 25:602-619. [PMID: 38910467 DOI: 10.2174/0113894501306843240606114854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 05/02/2024] [Accepted: 05/10/2024] [Indexed: 06/25/2024]
Abstract
Multi-target drug treatment has become popular as a substitute for traditional monotherapy. Monotherapy can lead to resistance and side effects. Multi-target drug discovery is gaining importance as data on bioactivity becomes more abundant. The design of multi-target drugs is expected to be an important development in the pharmaceutical industry in the near future. This review presents multi-target compounds against trypanosomatid parasites (Trypanosoma cruzi, T. brucei, and Leishmania sp.) and tuberculosis (Mycobacterium tuberculosis), which mainly affect populations in socioeconomically unfavorable conditions. The article analyzes the studies, including their chemical structures, viral strains, and molecular docking studies, when available. The objective of this review is to establish a foundation for designing new multi-target inhibitors for these diseases.
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Affiliation(s)
- Midiane Correia Gomes
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
| | - Emanuelly Karla Araújo Padilha
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
| | - Gustavo Rafael Angelo Diniz
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
| | - Edilma Correia Gomes
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
| | - Paulo Fernando da Silva Santos-Júnior
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
| | - Peng Zhan
- Department of Medicinal - Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, P.R. China
| | - Edeildo Ferreira da Siva-Júnior
- Research Group in Biological and Molecular Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus AC. Simões, CEP 57072-970, Maceió-AL, Brazil
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Norvihoho LK, Yin J, Zhou ZF, Han J, Chen B, Fan LH, Lichtfouse E. Mechanisms controlling the transport and evaporation of human exhaled respiratory droplets containing the severe acute respiratory syndrome coronavirus: a review. ENVIRONMENTAL CHEMISTRY LETTERS 2023; 21:1701-1727. [PMID: 36846189 PMCID: PMC9944801 DOI: 10.1007/s10311-023-01579-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 02/13/2023] [Indexed: 05/24/2023]
Abstract
Transmission of the coronavirus disease 2019 is still ongoing despite mass vaccination, lockdowns, and other drastic measures to control the pandemic. This is due partly to our lack of understanding on the multiphase flow mechanics that control droplet transport and viral transmission dynamics. Various models of droplet evaporation have been reported, yet there is still limited knowledge about the influence of physicochemical parameters on the transport of respiratory droplets carrying the severe acute respiratory syndrome coronavirus 2. Here we review the effects of initial droplet size, environmental conditions, virus mutation, and non-volatile components on droplet evaporation and dispersion, and on virus stability. We present experimental and computational methods to analyze droplet transport, and factors controlling transport and evaporation. Methods include thermal manikins, flow techniques, aerosol-generating techniques, nucleic acid-based assays, antibody-based assays, polymerase chain reaction, loop-mediated isothermal amplification, field-effect transistor-based assay, and discrete and gas-phase modeling. Controlling factors include environmental conditions, turbulence, ventilation, ambient temperature, relative humidity, droplet size distribution, non-volatile components, evaporation and mutation. Current results show that medium-sized droplets, e.g., 50 µm, are sensitive to relative humidity. Medium-sized droplets experience delayed evaporation at high relative humidity, and increase airborne lifetime and travel distance. By contrast, at low relative humidity, medium-sized droplets quickly shrink to droplet nuclei and follow the cough jet. Virus inactivation within a few hours generally occurs at temperatures above 40 °C, and the presence of viral particles in aerosols impedes droplet evaporation.
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Affiliation(s)
- Leslie Kojo Norvihoho
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Jing Yin
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Zhi-Fu Zhou
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Jie Han
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Bin Chen
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Li-Hong Fan
- The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061 Shaanxi People’s Republic of China
| | - Eric Lichtfouse
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
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3
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Strydom D, le Roux JD, Craig IK. State estimation for nonlinear state-space transmission models of tuberculosis. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2023; 43:339-357. [PMID: 35165919 DOI: 10.1111/risa.13901] [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: 06/14/2023]
Abstract
Given the high prevalence of tuberculosis (TB) and the mortality rate associated with the disease, numerous models, such as the Gammaitoni and Nucci (GN) model, were developed to model the risk of transmission. These models typically rely on a quanta generation rate as a measurement of infectivity. Since the quanta generation rate cannot be measured directly, the unique contribution of this work is to develop state estimators to estimate the quanta generation rate from available measurements. To estimate the quanta generation rate, the GN model is adapted into an augmented single-room GN model and a simplified two-room GN model. Both models are shown to be observable, i.e., it is theoretically possible to estimate the quanta generation rate given available measurements. Kalman filters are used to estimate the quanta generation rate. First, a continuous-time extended Kalman filter is used for both adapted models using a simulation and measurement sampling rate of 60 s. Accurate quanta generate rate estimates are achieved in both cases. A more realistic scenario is also considered with a measurement sampling rate of one day. For these estimates, a hybrid extended Kalman filter (HEKF) is used. Accurate quanta generation rate estimates are achieved for the more realistic scenario. Future work could potentially use the HEKFs, the adapted models, and real-time measurements in a control system feedback loop to reduce the transmission of TB in confined spaces such as hospitals.
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Affiliation(s)
- Duayne Strydom
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa
| | - Johan Derik le Roux
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa
| | - Ian Keith Craig
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa
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Liang W, Hu A, Hu P, Zhu J, Wang Y. Estimating the tuberculosis incidence using a SARIMAX-NNARX hybrid model by integrating meteorological factors in Qinghai Province, China. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023; 67:55-65. [PMID: 36271168 DOI: 10.1007/s00484-022-02385-0] [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: 11/26/2021] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Tuberculosis (TB) is recognized as being a major public health concern owing to its increase in Qinghai, China. In this study, we aimed to estimate the long-term effects of meteorological variables on TB incidence and construct an advanced hybrid model with seasonal autoregressive integrated moving average (SARIMA) and a neural network nonlinear autoregression (SARIMAX-NNARX) by integrating meteorological factors and evaluating the model fitting and prediction effect. During 2005-2017, TB experienced an upward trend with obvious periodic and seasonal characteristics, peaking in spring and winter. The results showed that TB incidence was positively correlated with average relative humidity (ARH) with a 2-month lag (β = 1.889, p = 0.003), but negatively correlated with average atmospheric pressure (AAP) with a 1-month lag (β = - 1.633, p = 0.012), average temperature (AT) with a 2-month lag (β = - 0.093, p = 0.027), and average wind speed (AWS) with a 0-month lag (β = - 13.221, p = 0.033), respectively. The SARIMA (3,1,0)(1,1,1)12, SARIMAX(3,1,0)(1,1,1)12, and SARIMAX(3,1,0)(1,1,1)12-NNARX(15,3) were considered preferred models based on the evaluation criteria. Of them, the SARIMAX-NNARX technique had smaller error values than the SARIMA and SARIMAX models in both fitting and forecasting aspects. The sensitivity analysis also revealed the robustness of the mixture forecasting model. Therefore, the SARIMAX-NNARX model by integrating meteorological variables can be used as an accurate method for forecasting the epidemic trends which would be great importance for TB prevention and control in the coming periods in Qinghai.
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Affiliation(s)
- Wenjuan Liang
- Department of Epidemiology, International School of Public Health and One Health, Hainan Medical University, Haikou, Hainan Province, 571199, People's Republic of China
- Department of Epidemiology and Health Statistics, School of Public Health, The Third Affiliated Hospital, Xinxiang Medical University, No. 601 Jinsui Road, Hongqi District, Xinxiang, Henan Province, 453003, People's Republic of China
| | - Ailing Hu
- Department of Epidemiology and Health Statistics, School of Public Health, The Third Affiliated Hospital, Xinxiang Medical University, No. 601 Jinsui Road, Hongqi District, Xinxiang, Henan Province, 453003, People's Republic of China
| | - Pan Hu
- Department of Epidemiology and Health Statistics, School of Public Health, The Third Affiliated Hospital, Xinxiang Medical University, No. 601 Jinsui Road, Hongqi District, Xinxiang, Henan Province, 453003, People's Republic of China
| | - Jinqin Zhu
- Department of Epidemiology and Health Statistics, School of Public Health, The Third Affiliated Hospital, Xinxiang Medical University, No. 601 Jinsui Road, Hongqi District, Xinxiang, Henan Province, 453003, People's Republic of China
| | - Yongbin Wang
- Department of Epidemiology and Health Statistics, School of Public Health, The Third Affiliated Hospital, Xinxiang Medical University, No. 601 Jinsui Road, Hongqi District, Xinxiang, Henan Province, 453003, People's Republic of China.
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DISPERSION OF AEROSOLIZED BACTERIA FROM ASIAN ELEPHANTS ( ELEPHAS MAXIMUS). J Zoo Wildl Med 2021; 52:749-754. [PMID: 34130422 DOI: 10.1638/2020-0173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2021] [Indexed: 11/21/2022] Open
Abstract
Transmission of tuberculosis typically requires close and prolonged contact with an infected individual. However, several cases of transmission between elephants and from elephants to humans or other animals without direct contact or over long distances have been reported. Elephants have been shown to be capable of producing aerosolized bacterial droplets, suggesting a possible route of transmission that is magnified by the size and force of the elephant respiratory tract. To investigate the dispersion and viability of aerosolized bacteria generated from the elephant respiratory tract, a pre-existing model with a proxy organism was used. A six-stage Andersen sampler was used to detect the proxy organism, a commensal elephant respiratory bacterium, at different locations around an elephant barn at a zoo. The amount of proxy organism detected at various time points and distances from the elephants indicates they are capable of dispersing viable bacterial aerosols further than humans can. The concentration of these aerosols is dependent on proximity to the elephants and does not remain at a high level for prolonged periods of time. These findings support the model of aerosol-mediated transmission of bacteria from elephants and can be used to improve disease management practices and prevent the spread of pathogens from elephants in zoos and other facilities.
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Influential factors and spatial-temporal distribution of tuberculosis in mainland China. Sci Rep 2021; 11:6274. [PMID: 33737676 PMCID: PMC7973528 DOI: 10.1038/s41598-021-85781-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 03/04/2021] [Indexed: 11/17/2022] Open
Abstract
Tuberculosis (TB) is an infectious disease that threatens human safety. Mainland China is an area with a high incidence of tuberculosis, and the task of tuberculosis prevention and treatment is arduous. This paper aims to study the impact of seven influencing factors and spatial–temporal distribution of the relative risk (RR) of tuberculosis in mainland China using the spatial–temporal distribution model and INLA algorithm. The relative risks and confidence intervals (CI) corresponding to average relative humidity, monthly average precipitation, monthly average sunshine duration and monthly per capita GDP were 1.018 (95% CI 1.001–1.034), 1.014 (95% CI 1.006–1.023), 1.026 (95% CI 1.014–1.039) and 1.025 (95% CI 1.011–1.040). The relative risk for average temperature and pressure were 0.956 (95% CI 0.942–0.969) and 0.767 (95% CI 0.664–0.875). Spatially, the two provinces with the highest relative risks are Xinjiang and Guizhou, and the remaining provinces with higher relative risks were mostly concentrated in the Northwest and South China regions. Temporally, the relative risk decreased year by year from 2013 to 2015. It was higher from February to May each year and was most significant in March. It decreased from June to December. Average relative humidity, monthly average precipitation, monthly average sunshine duration and monthly per capita GDP had positive effects on the relative risk of tuberculosis. The average temperature and pressure had negative effects. The average wind speed had no significant effect. Mainland China should adapt measures to local conditions and develop tuberculosis prevention and control strategies based on the characteristics of different regions and time.
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Manou M, Milgram J, Kelly P, Hoey S, Kenny K, Warde S, Kirby B. Mycobacterium bovis BCG Danish Strain 1331 isolated from a periarticular lesion in a domestic cat. J Small Anim Pract 2021; 62:924-928. [PMID: 33496016 DOI: 10.1111/jsap.13287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 11/12/2020] [Accepted: 11/26/2020] [Indexed: 11/30/2022]
Abstract
A 7-year-old male neutered domestic shorthair outdoor cat was referred for chronic left forelimb lameness, which had been treated with intra-articular injections of triamcinolone acetonide. A soft tissue swelling around the elbow joint, extending from the distal humerus to the proximal ulna, was surgically explored and biopsy samples obtained. Mycobacterium bovis was cultured from samples from the soft tissue and bone. The mycobacteria from the media were killed and the DNA extracted and tested on a multiplex real-time PCR for the absence of specific genes and the presence of mycobacterial genus markers. The PCR revealed bacillus Calmette-Guérin Danish Strain 1331; this was also isolated from the prescapular lymph node, muscle and bone, obtained at post mortem examination. Badgers had been vaccinated with the bacillus Calmette-Guérin vaccine SSI (Statens Serum Institute) in the area where the cat lived, in the spring and autumn of the previous year. To the authors' knowledge, this is the first report of infection with M. bovis bacillus Calmette-Guérin Danish Strain 1331 in a domestic cat, potentially associated with annual vaccination of badgers in the proximity of the cat's home.
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Affiliation(s)
- M Manou
- University College Dublin, University Veterinary Hospital, Belfield, Dublin 4, Ireland
| | - J Milgram
- The Hebrew University of Jerusalem, Koret School of Veterinary Medicine, P.O. Box 12, Rehovot, Israel
| | - P Kelly
- University College Dublin, University Veterinary Hospital, Belfield, Dublin 4, Ireland
| | - S Hoey
- University College Dublin, University Veterinary Hospital, Belfield, Dublin 4, Ireland
| | - K Kenny
- Department of Agriculture, Food and Marine, Co, Kildare, Ireland
| | - S Warde
- Department of Agriculture, Food and Marine, Co, Kildare, Ireland
| | - B Kirby
- University College Dublin, University Veterinary Hospital, Belfield, Dublin 4, Ireland
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Asare-Baah M, Séraphin MN, Salmon LAT, Lauzardo M. Effect of mixed strain infections on clinical and epidemiological features of tuberculosis in Florida. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 87:104659. [PMID: 33276149 PMCID: PMC7855629 DOI: 10.1016/j.meegid.2020.104659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 11/18/2020] [Accepted: 11/29/2020] [Indexed: 10/22/2022]
Abstract
Mixed infections with genetically distinct Mycobacterium tuberculosis (MTB) strains within a single host have been documented in different settings; however, this phenomenon is rarely considered in the management and care of new and relapse tuberculosis (T.B.) cases. This study aims to establish the epidemiological and clinical features of mixed infections among culture-confirmed T.B. patients enrolled in tuberculosis care at the Florida Department of Health (FDOH) and measure its association with T.B. mortality. We analyzed de-identified surveillance data of T.B. cases enrolled in T.B. care from April 2008 to January 2018. Mixed MTB infection was determined by the presence of more than one Copy Number Variant (CNV) in at least one locus, based on the genotype profile pattern of at least one isolate using 24-locus Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR). The prevalence of mixed MTB infections among the 4944 culture-confirmed TB cases included in this analysis was 2.6% (129). Increased odds of mixed infections were observed among middle-aged patients, 45-64 years (AOR = 2.38; 95% CI: 0.99, 5.69; p = 0.0513), older adults 65 years and above (AOR = 3.95; 95% CI: 1.63, 9.58; p = 0.0023) and patients with diabetes (OR = 1.77; 95% CI: 1.12, 2.80; p = 0.0150). There was no significant association between mixed infections and death. Our study provides insight into the epidemiological and clinical characteristics of patients with mixed MTB infections, which is essential in the management of T.B. patients.
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Affiliation(s)
- Michael Asare-Baah
- Department of Epidemiology, University of Florida, College of Public Health and Health Professions, College of Medicine, 2004 Mowry Road, P.O. Box 100231, Gainesville, FL 32610, United States; Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, P.O. Box 100009, Gainesville, FL 32610, United States.
| | - Marie Nancy Séraphin
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, P.O. Box 100009, Gainesville, FL 32610, United States; Division of Infectious Diseases and Global Medicine, University of Florida, College of Medicine, 2055 Mowry Road, P.O. Box 103600, Gainesville, FL 32610, United States
| | - LaTweika A T Salmon
- Florida Department of Health, Bureau of Tuberculosis Control, 4052 Bald Cypress Way, Bin A-20, Tallahassee, FL 32399, United States
| | - Michael Lauzardo
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, P.O. Box 100009, Gainesville, FL 32610, United States; Division of Infectious Diseases and Global Medicine, University of Florida, College of Medicine, 2055 Mowry Road, P.O. Box 103600, Gainesville, FL 32610, United States
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9
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Host and Mycobacterium tuberculosis interaction; expression of iNOS and Tbet genes from the host and virulence factors of the bacteria. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2019.100503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Küsel RR, Craig IK, Stoltz AC. Modeling the Airborne Infection Risk of Tuberculosis for a Research Facility in eMalahleni, South Africa. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:630-646. [PMID: 30229975 DOI: 10.1111/risa.13180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/30/2017] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
A detailed mathematical modeling framework for the risk of airborne infectious disease transmission in indoor spaces was developed to enable mathematical analysis of experiments conducted at the Airborne Infections Research (AIR) facility, eMalahleni, South Africa. A model was built using this framework to explore possible causes of why an experiment at the AIR facility did not produce expected results. The experiment was conducted at the AIR facility from August 31, 2015 to December 4, 2015, in which the efficacy of upper room germicidal ultraviolet (GUV) irradiation as an environmental control was tested. However, the experiment did not produce the expected outcome of having fewer infections in the test animal room than the control room. The simulation results indicate that dynamic effects, caused by switching the GUV lights, power outages, or introduction of new patients, did not result in the unexpected outcomes. However, a sensitivity analysis highlights that significant uncertainty exists with risk of transmission predictions based on current measurement practices, due to the reliance on large viable literature ranges for parameters.
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Affiliation(s)
- Ralf R Küsel
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria, South Africa
| | - Ian K Craig
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria, South Africa
| | - Anton C Stoltz
- Department of Internal Medicine, University of Pretoria, Pretoria, South Africa
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Patterson B, Morrow C, Singh V, Moosa A, Gqada M, Woodward J, Mizrahi V, Bryden W, Call C, Patel S, Warner D, Wood R. Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients. Gates Open Res 2018; 1:11. [PMID: 29355225 PMCID: PMC5757796 DOI: 10.12688/gatesopenres.12758.2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2018] [Indexed: 12/02/2022] Open
Abstract
Background: Tuberculosis (TB) is predominantly an airborne disease. However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, Mycobacterium tuberculosis (Mtb), has proven very challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of Mtb bacilli. Methods: We monitored each of 35 newly diagnosed, GeneXpert sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO 2 monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect Mtb in each of the bio-aerosol collection devices. Results: Mtb was detected in 27/35 (77.1%) of aerosol samples; 15/35 (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity. A correlation was found between cough rate and culturable bioaerosol. Mtb was detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5μm. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol. Conclusions: Mtb was identified in bio-aerosols exhaled by the majority of untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.
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Affiliation(s)
- Benjamin Patterson
- Division of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Carl Morrow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Vinayak Singh
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Atica Moosa
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Melitta Gqada
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Jeremy Woodward
- Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | | | - Shwetak Patel
- Computer Science and Engineering, Electrical Engineering DUB group, University of Washington, Seattle, USA
| | - Digby Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robin Wood
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
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Auld SC, Kasmar AG, Dowdy DW, Mathema B, Gandhi NR, Churchyard GJ, Rustomjee R, Shah NS. Research Roadmap for Tuberculosis Transmission Science: Where Do We Go From Here and How Will We Know When We're There? J Infect Dis 2017; 216:S662-S668. [PMID: 29112744 PMCID: PMC5793854 DOI: 10.1093/infdis/jix353] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
High rates of tuberculosis transmission are driving the ongoing global tuberculosis epidemic, and there is a pressing need for research focused on understanding and, ultimately, halting transmission. The ongoing tuberculosis–human immunodeficiency virus (HIV) coepidemic and rising rates of drug-resistant tuberculosis in parts of the world add further urgency to this work. Success in this research will require a concerted, multidisciplinary effort on the part of tuberculosis scientists, clinicians, programs, and funders and must span the research spectrum from biomedical sciences to the social sciences, public health, epidemiology, cost-effectiveness analyses, and operations research. Heterogeneity of tuberculosis disease, both among individual patients and among communities, poses a substantial challenge to efforts to interrupt transmission. As such, it is likely that effective interventions to stop transmission will require a combination of approaches that will vary across different epidemiologic settings. This research roadmap summarizes key gaps in our current understanding of transmission, as laid out in the preceding articles in this series. We also hope that it will be a call to action for the global tuberculosis community to make a sustained commitment to tuberculosis transmission science. Halting transmission today is an essential step on the path to end tuberculosis tomorrow.
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Affiliation(s)
- Sara C Auld
- School of Medicine and Rollins School of Public Health, Emory University
| | - Anne G Kasmar
- Bill and Melinda Gates Foundation, Seattle, Washington
| | - David W Dowdy
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore
| | - Barun Mathema
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York
| | - Neel R Gandhi
- School of Medicine and Rollins School of Public Health, Emory University
| | - Gavin J Churchyard
- Aurum Institute and the School of Public Health, University of Witwatersrand.,Advancing Care for tuberculosis and HIV, South African Medical Research Council, Johannesburg, South Africa
| | - Roxana Rustomjee
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - N Sarita Shah
- Division of Global HIV and Tuberculosis, Centers for Disease Control and Prevention, Atlanta, Georgia
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13
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Patterson B, Morrow C, Singh V, Moosa A, Gqada M, Woodward J, Mizrahi V, Bryden W, Call C, Patel S, Warner D, Wood R. Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients. Gates Open Res 2017; 1:11. [PMID: 29355225 PMCID: PMC5757796 DOI: 10.12688/gatesopenres.12758.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2017] [Indexed: 11/20/2022] Open
Abstract
Background: Tuberculosis (TB) is predominantly an airborne disease. However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, Mycobacterium tuberculosis (Mtb), has proven very challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of Mtb bacilli. Methods: We monitored each of 35 newly diagnosed, GeneXpert sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO 2 monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect Mtb in each of the bio-aerosol collection devices. Results: Mtb was detected in 27/35 (77.1%) of aerosol samples; 15/35 (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity, or cough rate. Mtb was detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5μm. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol. Conclusions: Mtb was identified in bio-aerosols exhaled by the majority of untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.
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Affiliation(s)
- Benjamin Patterson
- Division of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Carl Morrow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Vinayak Singh
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Atica Moosa
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Melitta Gqada
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Jeremy Woodward
- Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | | | - Shwetak Patel
- Computer Science and Engineering, Electrical Engineering DUB group, University of Washington, Seattle, USA
| | - Digby Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robin Wood
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
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14
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GUO C, DU Y, SHEN SQ, LAO XQ, QIAN J, OU CQ. Spatiotemporal analysis of tuberculosis incidence and its associated factors in mainland China. Epidemiol Infect 2017; 145:2510-2519. [PMID: 28595668 PMCID: PMC9148796 DOI: 10.1017/s0950268817001133] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 11/06/2022] Open
Abstract
Spatiotemporal analysis is an important tool to monitor changes of tuberculosis (TB) epidemiology, identify high-risk regions and guide resource allocation. However, there are limited data on the contributing factors of TB incidence. This study aimed to investigate the spatiotemporal pattern of TB incidence and its associated factors in mainland China during 2005-2013. Global Moran's I test, Getis-Ord Gi index and heat maps were used to examine the spatial clustering and seasonal patterns. Generalized Linear Mixed Model was applied to identify factors associated with TB incidence. TB incidence presented high geographical variations with two main hot spots, while a generally consistent seasonal pattern was observed with a peak in late winter. Furthermore, we found province-level TB incidence increased with the proportion of the elderly but decreased with Gross Demographic Product per capita and the male:female ratio. Meteorological factors also influenced TB incidence. TB showed obvious spatial clustering in mainland China and both the demographic and socio-economic factors and meteorological measures were associated with TB incidence. These results provide the related information to identify the high-risk districts and the evidence for the government to develop corresponding control measures.
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Affiliation(s)
- C. GUO
- State Key Laboratory of Organ Failure Research, Department of Biostatistics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
- The Jockey Club School of Public Health and Primary Care, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Y. DU
- State Key Laboratory of Organ Failure Research, Department of Biostatistics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - S. Q. SHEN
- State Key Laboratory of Organ Failure Research, Department of Biostatistics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - X. Q. LAO
- The Jockey Club School of Public Health and Primary Care, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - J. QIAN
- Department of Mathematics and Physics, School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - C. Q. OU
- State Key Laboratory of Organ Failure Research, Department of Biostatistics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
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15
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Fennelly KP, Jones-López EC. Quantity and Quality of Inhaled Dose Predicts Immunopathology in Tuberculosis. Front Immunol 2015; 6:313. [PMID: 26175730 PMCID: PMC4484340 DOI: 10.3389/fimmu.2015.00313] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 06/02/2015] [Indexed: 12/28/2022] Open
Abstract
Experimental animal models of tuberculosis (TB) have convincingly demonstrated that inhaled dose predicts immunopathology and survival. In contrast, the importance of inhaled dose has generally not been appreciated in TB epidemiology, clinical science, or the practice of TB control. Infectiousness of TB patients has traditionally been assessed using microscopy for acid-fast bacilli in the sputum, which should be considered only a risk factor. We have recently demonstrated that cough aerosol cultures from index cases with pulmonary TB are the best predictors of new infection among household contacts. We suggest that cough aerosols of M. tuberculosis are the best surrogates of inhaled dose, and we hypothesize that the quantity of cough aerosols is associated with TB infection versus disease. Although several factors affect the quality of infectious aerosols, we propose that the particle size distribution of cough aerosols is an important predictor of primary upper airway disease and cervical lymphadenitis and of immune responses in exposed hosts. We hypothesize that large droplet aerosols (>5 μ) containing M. tuberculosis deposit in the upper airway and can induce immune responses without establishing infection. We suggest that this may partially explain the large proportion of humans who never develop TB disease in spite of having immunological evidence of M. tuberculosis infection (e.g., positive tuberculin skin test or interferon gamma release assay). If these hypotheses are proven true, they would alter the current paradigm of latent TB infection and reactivation, further demonstrating the need for better biomarkers or methods of assessing TB infection and the risk of developing disease.
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Affiliation(s)
- Kevin P Fennelly
- Department of Medicine, Emerging Pathogens Institute, University of Florida , Gainesville, FL , USA
| | - Edward C Jones-López
- Section of Infectious Diseases, Boston Medical Center, Boston University School of Medicine , Boston, MA , USA
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16
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Mathematical Modelling and Tuberculosis: Advances in Diagnostics and Novel Therapies. Adv Med 2015; 2015:907267. [PMID: 26556559 PMCID: PMC4590968 DOI: 10.1155/2015/907267] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 02/18/2015] [Accepted: 02/26/2015] [Indexed: 11/18/2022] Open
Abstract
As novel diagnostics, therapies, and algorithms are developed to improve case finding, diagnosis, and clinical management of patients with TB, policymakers must make difficult decisions and choose among multiple new technologies while operating under heavy resource constrained settings. Mathematical modelling can provide helpful insight by describing the types of interventions likely to maximize impact on the population level and highlighting those gaps in our current knowledge that are most important for making such assessments. This review discusses the major contributions of TB transmission models in general, namely, the ability to improve our understanding of the epidemiology of TB. We focus particularly on those elements that are important to appropriately understand the role of TB diagnosis and treatment (i.e., what elements of better diagnosis or treatment are likely to have greatest population-level impact) and yet remain poorly understood at present. It is essential for modellers, decision-makers, and epidemiologists alike to recognize these outstanding gaps in knowledge and understand their potential influence on model projections that may guide critical policy choices (e.g., investment and scale-up decisions).
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17
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Simulation of risk of tuberculosis infection in healthcare workers in hospitals of an intermediate incidence country. Epidemiol Infect 2014; 143:2639-47. [PMID: 25544572 DOI: 10.1017/s0950268814003537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3-47·7] and 44% (95% CI 36·4-51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3-49·0) and 36% (95% CI 27·9-44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans.
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18
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Ní Bhuachalla D, Corner LA, More SJ, Gormley E. The role of badgers in the epidemiology of Mycobacterium bovis infection (tuberculosis) in cattle in the United Kingdom and the Republic of Ireland: current perspectives on control strategies. VETERINARY MEDICINE-RESEARCH AND REPORTS 2014; 6:27-38. [PMID: 30101094 PMCID: PMC6067767 DOI: 10.2147/vmrr.s53643] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Bovine tuberculosis (TB), caused by infection with Mycobacterium bovis, is a persistent problem in cattle herds in Ireland and the United Kingdom, resulting in hardship for affected farmers and substantial ongoing national exchequer expenditure. There is irrefutable scientific evidence that badgers are a reservoir of M. bovis infection and are implicated in the transmission of infection to cattle. A range of options for the control of TB in badgers is currently available or under development including culling of badgers, vaccination of badgers and cattle, and improved biosecurity to limit contact between the two species. It is unlikely that the eradication of TB from cattle will be achieved without the reservoir of M. bovis infection in badgers being controlled. The chances of success will, however, improve with greater knowledge of the disease in both species and an understanding of the epidemiological drivers of the transmission of infection between badgers and cattle.
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Affiliation(s)
| | - Leigh Al Corner
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland,
| | - Simon J More
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland, .,Centre for Veterinary Epidemiology and Risk Analysis, University College Dublin, Dublin, Ireland
| | - Eamonn Gormley
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland,
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19
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Turner RD, Bothamley GH. Cough and the transmission of tuberculosis. J Infect Dis 2014; 211:1367-72. [PMID: 25387581 DOI: 10.1093/infdis/jiu625] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 10/30/2014] [Indexed: 01/27/2023] Open
Abstract
Cough is a predominant feature of respiratory infection and, in tuberculosis, is of prime importance for transmitting infection. Tuberculosis is transmitted by the air, yet the process by which bacilli are aerosolized has received little attention. Features of cough may account for differences in transmission rates from source cases of pulmonary disease. We review the literature on the mechanisms and characteristics of cough in tuberculosis in the context of the dissemination of infection. Coughing is probably more important than other respiratory maneuvers, and characteristics of mucus may have an important role but data are scarce. Direct mechanisms of cough in tuberculosis are unknown, as are temporal and other patterns that correlate with the release of viable airborne bacilli. Other than antituberculous chemotherapy and masks, there are few methods of modulating cough in tuberculosis. This is an increasingly important area for research.
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Affiliation(s)
- Richard D Turner
- Department of Respiratory Medicine, Homerton University Hospital NHS Trust, London, United Kingdom
| | - Graham H Bothamley
- Department of Respiratory Medicine, Homerton University Hospital NHS Trust, London, United Kingdom
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20
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Natural infection of guinea pigs exposed to patients with highly drug-resistant tuberculosis. Tuberculosis (Edinb) 2011; 91:329-38. [PMID: 21478054 DOI: 10.1016/j.tube.2011.03.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/21/2011] [Accepted: 03/07/2011] [Indexed: 12/22/2022]
Abstract
A natural TB infection model using guinea pigs may provide useful information for investigating differences in transmission efficiency and establishment of active disease by clinical TB strains in a highly susceptible host under controlled environmental conditions. We sought to examine the capacity of naturally transmitted multidrug-resistant Mycobacterium tuberculosis to establish infection and produce active disease in guinea pigs. Guinea pigs were continuously exposed for 4 months to the exhaust air of a 6-bed multidrug-resistant tuberculosis inpatient hospital ward in South Africa. Serial tuberculin skin test reactions were measured to determine infection. All animals were subsequently evaluated for histologic disease progression at necropsy. Although 75% of the 362 exposed guinea pigs had positive skin test reactions [≥6 mm], only 12% had histopathologic evidence of active disease. Reversions (≥6 mm change) in skin test reactivity were seen in 22% of animals, exclusively among those with reactions of 6-13 mm. Only two of 86 guinea pigs with reversion had histological evidence of disease compared to 47% (31/66) of guinea pigs with large, non-reverting reactions. Immunosuppression of half the guinea pigs across all skin test categories did not significantly accelerate disease progression. In guinea pigs that reverted a skin test, a second positive reaction in 27 (33%) of them strongly suggested re-infection due to ongoing exposure. These results show that a large majority of guinea pigs naturally exposed to human-source strains of multidrug-resistant tuberculosis became infected, but that many resolved their infection and a large majority failed to progress to detectable disease.
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21
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Corner LAL, Murphy D, Gormley E. Mycobacterium bovis infection in the Eurasian badger (Meles meles): the disease, pathogenesis, epidemiology and control. J Comp Pathol 2010; 144:1-24. [PMID: 21131004 DOI: 10.1016/j.jcpa.2010.10.003] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 09/22/2010] [Accepted: 10/19/2010] [Indexed: 10/18/2022]
Abstract
Eurasian badgers (Meles meles) are an important wildlife reservoir of tuberculosis (Mycobacterium bovis) infection in Ireland and the United Kingdom. As part of national programmes to control tuberculosis in livestock, considerable effort has been devoted to studying the disease in badgers and this has lead to a rapid increase in our knowledge of tuberculosis in this host. Tuberculosis in badgers is a chronic infection and in a naturally-infected population the severity of disease can vary widely, from latent infection (infection without clinical signs and no visible lesions) to severe disease with generalized pathology. The high prevalence of pulmonary infection strongly supports the lungs as the principal site of primary infection and that inhalation of infectious aerosol particles is the principal mode of transmission. However, other routes, including transmission via infected bite wounds, are known to occur. The ante-mortem diagnosis of infection is difficult to achieve, as clinical examination and immunological and bacteriological examination of clinical samples are insensitive diagnostic procedures. Because infection in the majority of badgers is latent, the gross post-mortem diagnosis is also insensitive. A definitive diagnosis can only be made by the isolation of M. bovis. However, to gain a high level of sensitivity in the bacteriological examination, a large number of tissues from each badger must be cultured and sensitive culture methods employed. The transmission and maintenance of M. bovis in badger populations are complex processes where many factors influence within-population prevalence and rates of transmission. Badger social structures and the longevity of infected animals make them an ideal maintenance host for M. bovis infection. Badgers are directly implicated in the transmission of infection to cattle and the inability to eradicate the disease from cattle is, in part, a consequence of the interactions between the two species. A detailed understanding and knowledge of the epidemiology and pathogenesis of the disease are recognized as fundamental for devising new strategies to control infection with a view to limiting interspecies transmission. Vaccination, in spite of formidable challenges, is seen as the best long-term strategy option and studies with captive badgers have shown that vaccination with M. bovis bacillus Calmette-Guérin (BCG) induces protection when delivered by a variety of routes. Continued research is required to develop effective technologies to control the disease both in badgers and cattle. A combination of strategies, which employ the optimal use and targeting of resources, is likely to make a significant contribution towards eradication of the disease.
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Affiliation(s)
- L A L Corner
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin, Ireland.
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22
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Davies A, Thomson G, Walker J, Bennett A. A review of the risks and disease transmission associated with aerosol generating medical procedures. J Infect Prev 2009. [DOI: 10.1177/1757177409106456] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Several medical procedures, including bronchoscopy, intubation, and non-invasive ventilation, frequently used in the treatment or diagnosis of respiratory diseases, have been identified as potentially `aerosol generating'. It is thought that the nature of the `aerosol generating' procedure (`AGP') results in an infectious aerosol beyond that which would normally be released by a patient coughing, breathing, or talking, presenting an increased risk to any healthcare worker in proximity to the patient. Smoke models on dummies have provided a visual image of possible aerosol behaviour and indicate a possible zone of transmission. However, they are not necessarily representative of the behaviour of a respiratory aerosol and any infectious particles contained therein. No quantitative study has yet been carried out on AGPs. Bronchoscopy and sputum induction have been associated with nosocomial transmission of tuberculosis, and guidelines have been produced describing the appropriate ventilation, isolation and respiratory protection that should be applied when carrying out such procedures. The uncertainty surrounding AGPs makes it difficult to construct effective infection control policy. The protection of healthcare workers is paramount. However, during a pandemic, resources may be stretched. Therefore it is important to clarify whether these procedures do generate aerosols.
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Affiliation(s)
- Anna Davies
- Novel and Dangerous Pathogens, Health Protection Agency, Porton Down, Salisbury SP4 0JG
| | - Gail Thomson
- Novel and Dangerous Pathogens, Health Protection Agency
| | - Jimmy Walker
- Novel and Dangerous Pathogens, Health Protection Agency,
| | - Allan Bennett
- Novel and Dangerous Pathogens, Health Protection Agency
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23
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DAVIES PDO. The mycobacterioses. IMAGING 2008. [DOI: 10.1259/imaging/25758678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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