Publications
362 results found
Okell LC, Drakeley CJ, Bousema T, et al., 2008, Modelling the impact of artemisinin combination therapy and long-acting treatments on malaria transmission intensity, PLoS Med, Vol: 5, Pages: e226-e226, ISSN: 1549-1676
BACKGROUND: Artemisinin derivatives used in recently introduced combination therapies (ACTs) for Plasmodium falciparum malaria significantly lower patient infectiousness and have the potential to reduce population-level transmission of the parasite. With the increased interest in malaria elimination, understanding the impact on transmission of ACT and other antimalarial drugs with different pharmacodynamics becomes a key issue. This study estimates the reduction in transmission that may be achieved by introducing different types of treatment for symptomatic P. falciparum malaria in endemic areas. METHODS AND FINDINGS: We developed a mathematical model to predict the potential impact on transmission outcomes of introducing ACT as first-line treatment for uncomplicated malaria in six areas of varying transmission intensity in Tanzania. We also estimated the impact that could be achieved by antimalarials with different efficacy, prophylactic time, and gametocytocidal effects. Rates of treatment, asymptomatic infection, and symptomatic infection in the six study areas were estimated using the model together with data from a cross-sectional survey of 5,667 individuals conducted prior to policy change from sulfadoxine-pyrimethamine to ACT. The effects of ACT and other drug types on gametocytaemia and infectiousness to mosquitoes were independently estimated from clinical trial data. Predicted percentage reductions in prevalence of infection and incidence of clinical episodes achieved by ACT were highest in the areas with low initial transmission. A 53% reduction in prevalence of infection was seen if 100% of current treatment was switched to ACT in the area where baseline slide-prevalence of parasitaemia was lowest (3.7%), compared to an 11% reduction in the highest-transmission setting (baseline slide prevalence = 57.1%). Estimated percentage reductions in incidence of clinical episodes were similar. The absolute size of the public health impact, however, was greater in
Van Kerkhove MD, Ly S, Holl D, et al., 2008, Frequency and types of contact with poultry and potential risk of H5N1 transmission to humans in rural Cambodia, Influenza and Other Respiratory Viruses, Vol: 2, Pages: 155-163
Okell LC, Drakeley CJ, Ghani AC, et al., 2008, Reduction of transmission from malaria patients by artemisinin combination therapies: a pooled analysis of six randomized trials, Malar J, Vol: 7, ISSN: 1475-2875
BACKGROUND: Artemisinin combination therapies (ACT), which are increasingly being introduced for treatment of Plasmodium falciparum malaria, are more effective against sexual stage parasites (gametocytes) than previous first-line antimalarials and therefore have the potential to reduce parasite transmission. The size of this effect is estimated in symptomatic P. falciparum infections. METHODS: Data on 3,174 patients were pooled from six antimalarial trials conducted in The Gambia and Kenya. Multivariable regression was used to investigate the role of ACT versus non-artemisinin antimalarial treatment, treatment failure, presence of pre-treatment gametocytes and submicroscopic gametocytaemia on transmission to mosquitoes and the area under the curve (AUC) of gametocyte density during the 28 days of follow up. RESULTS: ACT treatment was associated with a significant reduction in the probability of being gametocytaemic on the day of transmission experiments (OR 0.20 95% CI 0.16-0.26), transmission to mosquitoes by slide-positive gametocyte carriers (OR mosquito infection 0.49 95% CI 0.33-0.73) and AUC of gametocyte density (ratio of means 0.35 95% CI 0.31-0.41). Parasitological treatment failure did not account for the difference between ACT and non-artemisinin impact. The presence of slide-positive gametocytaemia prior to treatment significantly reduced ACT impact on gametocytaemia (p < 0.001). Taking account of submicroscopic gametocytaemia reduced estimates of ACT impact in a high transmission setting in Kenya, but not in a lower transmission setting in the Gambia. CONCLUSION: Treatment with ACT significantly reduces infectiousness of individual patients with uncomplicated falciparum malaria compared to previous first line treatments. Rapid treatment of cases before gametocytaemia is well developed may enhance the impact of ACT on transmission.
Filipe JAN, Riley EM, Drakeley CJ, et al., 2007, Determination of the processes driving the acquisition of immunity to malaria using a mathematical transmission model, PLOS COMPUTATIONAL BIOLOGY, Vol: 3, Pages: 2569-2579
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- Citations: 132
Boily MC, Asghar Z, Garske T, et al., 2007, Influence of selected formation rules for finite population networks with fixed macrostructures: Implications for individual-based model of infectious diseases, MATHEMATICAL POPULATION STUDIES, Vol: 14, Pages: 237-267, ISSN: 0889-8480
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- Citations: 10
Risley CL, Ward H, Choudhury B, et al., 2007, Geographical and demographic clustering of gonorrhoea in London, SEXUALLY TRANSMITTED INFECTIONS, Vol: 83, Pages: 481-487, ISSN: 1368-4973
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- Citations: 42
Truscott J, Garske T, Chis-Ster I, et al., 2007, Control of a highly pathogenic H5N1 avian influenza outbreak in the GB poultry flock, PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 274, Pages: 2287-2295, ISSN: 0962-8452
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- Citations: 55
Clarke P, Will RG, Ghani AC, 2007, Is there the potential for an epidemic of variant Creutzfeld-Jakob disease via blood transfusion in the UK?, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 4, Pages: 675-684, ISSN: 1742-5689
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- Citations: 22
White RG, Cooper BS, Kedhar A, et al., 2007, Quantifying HIV-1 transmission due to contaminated injections, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 104, Pages: 9794-9799, ISSN: 0027-8424
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- Citations: 19
Gras L, Kesselring AM, Griffin JT, et al., 2007, CD4 cell counts of 800 cells/mm<SUP>3</SUP> or greater after 7 years of highly active antiretroviral therapy are feasible in most patients starting with 350 cells/mm<SUP>3</SUP> or greater, JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES, Vol: 45, Pages: 183-192, ISSN: 1525-4135
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- Citations: 132
Jewell NP, Lei X, Ghani AC, et al., 2007, Non-parametric estimation of the case fatality ratio with competing risks data: An application to Severe Acute Respiratory Syndrome (SARS), STATISTICS IN MEDICINE, Vol: 26, Pages: 1982-1998, ISSN: 0277-6715
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- Citations: 32
Garske T, Clarke P, Ghani AC, 2007, The Transmissibility of Highly Pathogenic Avian Influenza in Commercial Poultry in Industrialised Countries, PLOS ONE, Vol: 2, ISSN: 1932-6203
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- Citations: 52
Clarke PS, Ghani AC, 2007, A note on parameter estimation for variant Creutzfeldt-Jakob disease epidemic models, STATISTICS IN MEDICINE, Vol: 26, Pages: 546-552, ISSN: 0277-6715
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- Citations: 1
Garske T, Ward HJT, Clarke P, et al., 2006, Factors determining the potential for onward transmission of variant Creutzfeldt-Jakob disease via surgical instruments, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 3, Pages: 757-766, ISSN: 1742-5689
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- Citations: 11
Sabatelli L, Ghani A, Hotez P, et al., 2006, Human hookworm vaccine trial: Modeling trial efficacy and health impact, AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, Vol: 75, Pages: 319-319, ISSN: 0002-9637
Kwong GPS, Ghani AC, Rode RA, et al., 2006, Comparison of the risks of atherosclerotic events versus death from other causes associated with antiretroviral use, AIDS, Vol: 20, Pages: 1941-1950, ISSN: 0269-9370
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- Citations: 32
Sethi G, Holden BM, Gaffney J, et al., 2006, HIV, sexually transmitted infections, and risk behaviours in male sex workers in London over a 10 year period, SEXUALLY TRANSMITTED INFECTIONS, Vol: 82, Pages: 359-363, ISSN: 1368-4973
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- Citations: 36
Ward HJT, Will RG, Ghani A, et al., 2006, An update on variant CJD (vCJD), secondary transmission and prevalence, EUROPEAN JOURNAL OF NEUROLOGY, Vol: 13, Pages: 306-307, ISSN: 1351-5101
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- Citations: 1
Choudhury B, Risley CL, Ghani AC, et al., 2006, Identification of individuals with gonorrhoea within sexual networks: a population-based study, LANCET, Vol: 368, Pages: 139-146, ISSN: 0140-6736
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- Citations: 64
Griffin JT, Fraser C, Gras L, et al., 2006, The effect on treatment comparisons of different measurement frequencies in human immunodeficiency virus observational databases, AMERICAN JOURNAL OF EPIDEMIOLOGY, Vol: 163, Pages: 676-683, ISSN: 0002-9262
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- Citations: 11
Leung GM, Lim WW, Ho L-M, et al., 2006, Seroprevalence of IgG antibodies to SARS-coronavirus in asymptomatic or subclinical population groups, Epidemiol Infect, Vol: 134, Pages: 211-221
Chen M, Ghani A, Edmunds JW, 2006, Mind the gap: the effect of time between sex with two consecutive partners on the persistence of gonorrhoea and HIV, INTERNATIONAL JOURNAL OF STD & AIDS, Vol: 17, Pages: 34-35, ISSN: 0956-4624
Donnelly CA, Riley S, Fraser C, et al., 2006, Epidemiological analysis of SARS: a novel infectious disease, Challenges of Severe Acute Respiratory Syndrome, Editors: Chan, Wong, Publisher: Elsevier, Pages: 9-30
Turner KME, Adams EJ, Gay N, et al., 2006, Developing a realistic sexual network model of chlamydia transmission in Britain, THEORETICAL BIOLOGY AND MEDICAL MODELLING, Vol: 3
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- Citations: 56
van Sighem A, Danner S, Ghani AC, et al., 2005, Mortality in patients with successful initial response to highly active antiretroviral therapy is still higher than in non-HIV-Infected individuals, JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES, Vol: 40, Pages: 212-218, ISSN: 1525-4135
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- Citations: 47
Ferguson NM, Donnelly CA, Hooper J, et al., 2005, Adherence to antiretroviral therapy and its impact on clinical outcome in HIV-infected patients, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 2, Pages: 349-363, ISSN: 1742-5689
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- Citations: 23
Ghani AC, Donnelly CA, Cox DR, et al., 2005, Methods for estimating the case fatality ratio for a novel, emerging infectious disease, American Journal of Epidemiology, Vol: 162, Pages: 479-486, ISSN: 0002-9262
During the course of an epidemic of a potentially fatal disease, it is important that the case fatality ratio be well estimated. The authors propose a novel method for doing so based on the Kaplan-Meier survival procedure, jointly considering two outcomes (death and recovery), and evaluate its performance by using data from the 2003 epidemic of severe acute respiratory syndrome in Hong Kong, People's Republic of China. They compare this estimate obtained at various points in the epidemic with the case fatality ratio eventually observed; with two commonly quoted, naïve estimates derived from cumulative incidence and mortality statistics at single time points; and with estimates in which a parametric mixture model is used. They demonstrate the importance of patient characteristics regarding outcome by analyzing subgroups defined by age at admission to the hospital.
Donnelly CA, Bartley LM, Ghani AC, et al., 2005, Gender difference in HIV-1 RNA viral loads, HIV MEDICINE, Vol: 6, Pages: 170-178, ISSN: 1464-2662
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- Citations: 44
Clarke P, Ghani AC, 2005, Projections of the future course of the primary vCJD epidemic in the UK: inclusion of subclinical infection and the possibility of wider genetic susceptibility, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 2, Pages: 19-31, ISSN: 1742-5689
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- Citations: 54
Ghani AC, Aral SO, 2005, Patterns of sex worker-client contacts and their implications for the persistence of sexually transmitted infections, JOURNAL OF INFECTIOUS DISEASES, Vol: 191, Pages: S34-S41, ISSN: 0022-1899
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- Citations: 28
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