Browsing by Author "Kenyon, Chris"

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    50 years of Emmonsia disease in humans: the dramatic emergence of a cluster of novel fungal pathogens
    (Public Library of Science, 2015) Schwartz, Ilan S; Kenyon, Chris; Feng, Peiying; Govender, Nelesh P; Dukik, Karolina; Sigler, Lynne; Jiang, Yanping; Stielow, J Benjamin; Muñoz, José F; Cuomo, Christina A; Botha, Alfred; Stchigel, Alberto M; De Hoog, G Sybren
    New species of Emmonsia-like fungi, with phylogenetic and clinical similarities to Blastomyces and Histoplasma, have emerged as causes of systemic human mycoses worldwide. They differ from classical Emmonsia species by producing a thermally-dependent, yeast-like phase rather than adiaspores, and by causing disseminated infections, predominantly in immunocompromised patients and often with high case-fatality rates. Such differences will be important for clinicians to consider in diagnosis and patient management, and for microbiologists who may encounter these fungi with increasing frequency.
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    Cognitive dissonance as an explanation of the genesis, evolution and persistence of Thabo Mbeki's HIV denialism
    (2008) Kenyon, Chris
    The ongoing damage that the newer forms of HIV denialism are visiting upon our country is evidenced by the recent firing of Nozizwe Madlala-Routledge, the South African Deputy Minister of Health. It is widely believed that the underlying reason for her dismissal was her support of orthodox HIV treatment and prevention strategies and her disdain for HIV denialism. This paper seeks to understand the origins, spread and metamorphosis of President Thabo Mbeki's HIV denialism in South Africa. Using the theory of cognitive dissonance, I argue that, given the structural beliefs of the African National Congress (ANC) and the pattern of emergence of HIV in the 1980s, a degree of scepticism around the putative science of HIV was probable in ANC circles. On assuming the Presidency in 1999, Mbeki tapped into this scepticism to formulate his initial biological version of HIV denialism, which claimed that 'a virus can't cause a syndrome.' The steady erosion of support for this flagrant HIV denialism, together with the rise of neoliberal thinking in the ANC, would lead to the evolution of this biological denialism into a form of treatment denialism. This ideology argued against the widespread provision and use of antiretroviral treatment. Empirical evidence is presented to demonstrate the extent to which ongoing HIV denial in the general population is continuing to fuel the spread of HIV.
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    Gonococcal resistance can be viewed productively as part of a syndemic of antimicrobial resistance: an ecological analysis of 30 European countries
    (2020-06-30) Kenyon, Chris; Manoharan-Basil, Sheeba S; Van Dijck, Christophe
    Background It is unclear how important bystander selection is in the genesis of antimicrobial resistance (AMR) in Neisseria gonorrhoeae. Methods We assessed bystander selection in a novel way. Mixed-effects linear regression was used to assess if country-level prevalence of gonococcal AMR in 30 European countries predicts homologous AMR in other bacteria. The data used was from the European Antimicrobial Resistance Surveillance Network. Results The prevalence of gonococcal ciprofloxacin resistance was found to be positively associated with AMR prevalence in E. coli (coef. 0.52; P = 0.007), Acinetobacter spp. (coef. 0.13; P = 0.044) and Pseudomonas aeruginosa (coef. 0.36; P = 0.020) but not Klebsiella pneumoniae. Azithromycin resistance in N. gonorrhoeae was positively associated with macrolide resistance in Streptococcus pneumoniae (coef. 0.01; P = 0.018). No association was found for cephalosporins. Conclusions Gonococcal AMR is linked to that in other bacteria. This finding is likely explained by high antimicrobial consumption in affected populations and provides additional motivation for strengthening antimicrobial stewardship programs.
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    HIV prevalence by race co-varies closely with concurrency and number of sex partners in South Africa
    (Public Library of Science, 2013) Kenyon, Chris; Buyze, Jozefien; Colebunders, Robert
    BACKGROUND: HIV prevalence differs by more than an order of magnitude between South Africa's racial groups. Comparing the sexual behaviors and other risk factors for HIV transmission between the different races may shed light on the determinants of South Africa's generalized HIV epidemic. METHODS: Five nationally representative and one city-representative population-based surveys of sexual behavior were used to assess the extent to which various risk factors co-varied with HIV prevalence by race in South Africa. RESULTS: In 2004, the prevalence of HIV was 0.5%, 1%, 3.2% and 19.9% in 15-49 year old whites, Indians, coloureds and blacks respectively. The risk factors which co-varied with HIV prevalence by race in the six surveys were age of sexual debut (in five out of five surveys for men and three out of six surveys for women), age gap (zero surveys in men and three in women), mean number of sex partners in the previous year (five surveys in men and three in women) and concurrent partnerships (five surveys in men and one in women). Condom usage and circumcision were both more prevalent in the high HIV prevalence groups. The reported prevalence of concurrency was 6 to 17 times higher in the black as opposed to the white men in the five surveys. CONCLUSIONS: The differences in sexual behavior in general, and the prevalence of concurrency and the number of sexual partners in particular, offer a plausible and parsimonious cause to explain a part of the differing prevalences of HIV between South Africa's racial groups.
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    Increases in condomless chemsex associated with HIV acquisition in MSM but not heterosexuals attending a HIV testing center in Antwerp, Belgium
    (BioMed Central, 2018-10-19) Kenyon, Chris; Wouters, Kristien; Platteau, Tom; Buyze, Jozefien; Florence, Eric
    Background It has been speculated that the prevalence of chemsex is increasing in men who have sex with men and that this may be playing a role in the spread of HIV. Methods We assessed if the prevalence of reported chemsex was increasing and if chemsex was associated with HIV infection in clients attending the ‘Helpcenter’, Antwerp, between 2011 and 2017. This is a HIV/STI testing center that offers HIV/STI testing to HIV-uninfected individuals from key populations including MSM. Results We found an increase in the reporting of condomless sex associated with the use of a number of drugs, including ecstasy, amphetamines, GHB and cocaine in MSM (from 8 to 17%) but not in heterosexuals. Reporting condomless chemsex was associated with HIV infection (adjusted odds ratio 5.7 [95% confidence interval 3.2–10.4]). Conclusions Our findings provide further evidence of the importance of asking MSM clients about the use of psychoactive substances during consultations and tailoring interventions such as pre exposure prophylaxis, more frequent STI screening and substance abuse counseling accordingly.
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    Migration intensity has no effect on peak HIV prevalence: an ecological study
    (BioMed Central Ltd, 2014) Kenyon, Chris; Colebunders, Robert; Voeten, Helene; Lurie, Mark
    BACKGROUND:Correctly identifying the determinants of generalized HIV epidemics is crucial to bringing down ongoing high HIV incidence in these countries. High rates of migration are believed to be an important determinant of HIV prevalence. This study has two aims. Firstly, it evaluates the ecological association between levels of internal and international migration and national peak HIV prevalence using thirteen variables from a variety of sources to capture various aspects of internal and international migration intensity. Secondly, it examines the relationship between circular migration and HIV at an individual and population-level in South Africa. METHODS: Linear regression was used to analyze the association between the various measures of migration intensity and peak national HIV prevalence for 141 countries and HIV prevalence by province and ethnic group in South Africa. RESULTS: No evidence of a positive ecological association between national migration intensity and HIV prevalence was found. This remained the case when the analyses were limited to the countries of sub-Saharan Africa. On the whole, countries with generalized HIV epidemics had lower rates of internal and external migration. Likewise, no association was found between migration and HIV positivity at an individual or group-level in South Africa. CONCLUSION: These results do not support the thesis that migration measured at the country level plays a significant role in determining peak HIV prevalence.
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    What is the optimal first line antiretroviral therapy in resource-limited settings?
    (Public Library of Science, 2012) Kenyon, Chris; Colebunders, Robert
    A perspective by Chris Kenyon and Robert Colebunders discusses policy implications for use of first line antiretroviral therapies in resource-limited settings, emerging from a new research study conducted by Campbell and colleagues.
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    Where have all the susceptible gonococci gone? A historical review of changes in MIC distribution over the past 75 years
    (2019-12-27) Kenyon, Chris; Laumen, Jolein; Van Den Bossche, Dorien; Van Dijck, Christophe
    Abstract Background Does the emergence of antimicrobial resistance in Neisseria gonorrhoeae include the erasure of highly susceptible strains or does it merely involve a stretching of the MIC distribution? If it was the former this would be important to know as it would increase the probability that the loss of susceptibility is irreversible. Methods We conducted a historical analysis based on a literature review of changes of N. gonorrhoeae MIC distribution over the past 75 years for 3 antimicrobials (benzylpenicillin, ceftriaxone and azithromycin) in five countries (Denmark, Japan, South Africa, the United Kingdom and the United States). Results Changes in MIC distribution were most marked for benzylpenicillin and showed evidence of a right shifting of MIC distribution that was associated with a reduction/elimination of susceptible strains in all countries. In the case of ceftriaxone and azithromycin, where only more recent data was available, right shifting was also found in all countries but the extent of right shifting varied and the evidence for the elimination of susceptible strains was more mixed. Conclusions The finding of right shifting of MIC distribution combined with reduction/elimination of susceptible strains is of concern since it suggests that this shifting may not be reversible. Since excess antimicrobial consumption is likely to be responsible for this right shifting, this insight provides additional impetus to promote antimicrobial stewardship.