Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Alison C. Roxby is active.

Publication


Featured researches published by Alison C. Roxby.


Clinical Infectious Diseases | 2009

Strongyloidiasis in Transplant Patients

Alison C. Roxby; Geoffrey S. Gottlieb; Ajit P. Limaye

Strongyloides stercoralis is an intestinal nematode that can persist in the human host for decades after the initial infection and can progress to fulminant hyperinfection syndrome in immunocompromised hosts. We describe a patient who died of Strongyloides hyperinfection syndrome 2 months after orthotopic heart transplantation and discuss approaches to prevention, diagnosis, and treatment. Current practice guidelines recommend screening for and treatment of Strongyloides infection before transplantation, but physicians in the United States often miss opportunities to identify patients with chronic strongyloidiasis. Screening tests have limitations, and clinical suspicion remains an important component of the evaluation before transplantation. After immunocompromised patients develop hyperinfection syndrome, diagnosis is often delayed and mortality is high, so emphasis must be placed on screening and treatment before transplantation. We review current strategies for prevention, diagnosis, and treatment of chronic intestinal strongyloidiasis in patients who will undergo transplantation and discuss the clinical features and management of Strongyloides hyperinfection syndrome in transplant recipients.


Clinical Infectious Diseases | 2014

Compartmentalized Cytomegalovirus Replication and Transmission in the Setting of Maternal HIV-1 Infection

Jennifer A. Slyker; Carey Farquhar; Claire Atkinson; Kristjana Ásbjörnsdóttir; Alison C. Roxby; Alison L. Drake; James Kiarie; Anna Wald; Michael Boeckh; Barbra A. Richardson; Katherine Odem-Davis; Grace John-Stewart; Vincent C. Emery

BACKGROUND Cytomegalovirus (CMV) infection is associated with adverse outcomes in human immunodeficiency virus (HIV)-exposed infants. Determinants of vertical CMV transmission in the setting of maternal HIV-1 infection are not well-defined. METHODS CMV and HIV-1 levels were measured in plasma, cervical secretions, and breast milk of 147 HIV-1-infected women to define correlates of maternal CMV replication and infant CMV acquisition. RESULTS Although few women had detectable CMV in plasma (4.8%), the majority had detectable CMV DNA in cervical secretions (66%) and breast milk (99%). There was a strong association between cervical CMV detection during pregnancy and later breast milk levels (β = 0.47; P = .005). Plasma HIV-1 level and CD4 counts were associated with CMV in the cervix and breast milk. However HIV-1 levels within the cervix and breast milk were not associated with CMV within these compartments. Maternal breast milk CMV levels (hazard ratio [HR], 1.4; P = .003) and maternal CD4 < 450 cells/mm(3) (HR, 1.8; P = .008) were independently associated with infant CMV acquisition; each log10 increase in breast milk CMV was associated with a 40% increase in infant infection. The breast milk CMV level required to attain a 50% probability of CMV transmission increased with higher maternal CD4 counts, increasing from 3.55 log10 CMV DNA copies/mL at a CD4 count of 350 cells/mm(3) to 5.50 log10 CMV DNA copies/mL at a CD4 count of 1000 cells/mm(3). CONCLUSIONS Breast milk CMV levels and maternal CD4 count are major determinants of CMV transmission in the setting of maternal HIV-1. Maternal immune reconstitution or lowering breast milk CMV levels may reduce vertical CMV transmission.


Aids Patient Care and Stds | 2013

Pregnant Women and Disclosure to Sexual Partners After Testing HIV-1–Seropositive During Antenatal Care

Alison C. Roxby; Daniel Matemo; Alison L. Drake; John Kinuthia; Grace John-Stewart; Francisca Ongecha-Owuor; James Kiarie; Carey Farquhar

In African countries highly affected by human immunodeficiency virus-1 (HIV-1) women are more likely to be tested for HIV-1 than men due to scale-up of antenatal testing programs to prevent mother-to-child transmission (PMTCT) of HIV-1. As part of standard post-test counseling HIV-1 seropositive women are advices to disclose their status to their partners and refer them for testing. Disclosure to male partners antenatally has been associated with improved adherence to prevention of PMTCT regimens better infant feeding practices safer sex practices and increase male partner testing. Despite these findings promotion of male partner disclosure is not a central component of most PMTCT programs. While barriers to female-to-male disclosure are well-described and include socio-economic vulnerability fear of violence of abandonment and family stigma little has been published describing how to promote disclosure to male partners after antenatal testing. This study followed Kenyan HIV-1 – seropositive women enrolled in a randomized clinical trial of herpes suppression during pregnancy until 1 year postpartum to determine disclosure rates and to assess timing and correlates of disclosure. Our hypothesis was that women who were counseled and supported to disclose their HIV-1 status as part of a longitudinal research study would over time be more likely to disclose to partners. There is clear evidence that promoting disclosure to partners in the antenatal setting can lead to both individual and public health benefits but little is known about how to achieve this goal. The research indicates that rather than focusing on strategies that focus on strategies that promote disclosure by women such as counseling there should be an emphasis on strategies that make HIV-1 testing more appealing to men in this setting such as shifts in infrastructure promoting ease and availability of testing and reduction of stigma and barriers to male partner HIV-1 testing and treatment. In conclusion the research shows that mothers diagnosed with HIV-1 antenatally face challenges in disclosing to their male partners.


The Journal of Infectious Diseases | 2012

Valacyclovir Suppressive Therapy Reduces Plasma and Breast Milk HIV-1 RNA Levels During Pregnancy and Postpartum: A Randomized Trial

Alison L. Drake; Alison C. Roxby; Francisca Ongecha-Owuor; James Kiarie; Grace John-Stewart; Anna Wald; Barbra A. Richardson; Jane Hitti; Julie Overbaugh; Sandra Emery; Carey Farquhar

BACKGROUND The effect of herpes simplex virus type 2 (HSV-2) suppression on human immunodeficiency virus type 1 (HIV-1) RNA in the context of prevention of mother-to-child transmission (PMTCT) interventions is unknown. METHODS Between April 2008 and August 2010, we conducted a randomized, double-blind trial of twice daily 500 mg valacyclovir or placebo beginning at 34 weeks gestation in 148 HIV-1/HSV-2 coinfected pregnant Kenyan women ineligible for highly active antiretroviral therapy (CD4 > 250 cells/mm(3)). Women received zidovudine and single dose nevirapine for PMTCT and were followed until 12 months postpartum. RESULTS Mean baseline plasma HIV-1 RNA was 3.88 log(10) copies/mL. Mean plasma HIV-1 was lower during pregnancy (-.56 log(10) copies/mL; 95% confidence interval [CI], -.77 to -.34) and after 6 weeks postpartum (-.51 log(10) copies/mL; 95% CI, -.73 to -.30) in the valacyclovir arm than the placebo arm. Valacyclovir reduced breast milk HIV-1 RNA detection at 6 and 14 weeks postpartum compared with placebo (30% lower, P = .04; 46% lower, P = .01, respectively), but not after 14 weeks. Cervical HIV-1 RNA detection was similar between arms (P = .91). CONCLUSIONS Valacyclovir significantly decreased early breast milk and plasma HIV-1 RNA among women receiving PMTCT. CLINICAL TRIALS REGISTRATION NCT00530777.


PLOS ONE | 2014

Maternal Valacyclovir and Infant Cytomegalovirus Acquisition A Randomized Controlled Trial among HIV-Infected Women

Alison C. Roxby; Claire Atkinson; Kristjana Ásbjörnsdóttir; Carey Farquhar; James Kiarie; Alison L. Drake; Anna Wald; Michael Boeckh; Barbra A. Richardson; Vincent C. Emery; Grace John-Stewart; Jennifer A. Slyker

Background Studies in HIV-1-infected infants and HIV-1-exposed, uninfected infants link early cytomegalovirus (CMV) acquisition with growth delay and cognitive impairment. We investigated maternal valacyclovir to delay infant acquisition of CMV. Methods Pregnant women with HIV-1, HSV-2 and CD4 count >250 cells/µl were randomized at 34 weeks gestation to 500 mg twice-daily valacyclovir or placebo for 12 months. Maternal CMV DNA was measured in plasma at 34 weeks gestation, in cervical secretions at 34 and 38 weeks gestation, and in breast milk at 7 postpartum timepoints; infant CMV DNA was measured in dried blood spots at 8 timepoints including birth. Results Among 148 women, 141 infants were compared in intent-to-treat analyses. Maternal and infant characteristics were similar between study arms. Infant CMV acquisition did not differ between study arms, with 46/70 infants (66%) in placebo arm and 47/71 infants (66%) in the valacyclovir arm acquiring CMV; median time to CMV detection did not differ. CMV DNA was detected in 92% of 542 breast milk specimens with no difference in CMV level between study arms. Change in cervical shedding of CMV DNA between baseline and 38 weeks was 0.40-log greater in the placebo arm than the valacyclovir arm (p = 0.05). Conclusions In this cohort of HIV-1-seropositive mothers, two-thirds of infants acquired CMV by one year. Maternal valacyclovir had no effect on timing of infant CMV acquisition or breast milk CMV viral loads, although it modestly reduced cervical CMV shedding. Maternal prophylaxis to reduce infant CMV acquisition warrants further evaluation in trials with antiviral agents. Trials Registration ClinicalTrials.gov NCT00530777


Journal of Acquired Immune Deficiency Syndromes | 2015

Depot medroxyprogesterone acetate use is associated with elevated innate immune effector molecules in cervicovaginal secretions of HIV-1-uninfected women

Brandon L. Guthrie; Andrea Introini; Alison C. Roxby; Robert Y. Choi; Rose Bosire; Barbara Lohman-Payne; Taha Hirbod; Carey Farquhar; Kristina Broliden

Objective:The effects of sex hormones on the immune defenses of the female genital mucosa and its susceptibility to infections are poorly understood. The injectable hormonal contraceptive depot medroxyprogesterone acetate (DMPA) may increase the risk for HIV-1 acquisition. We assessed the local concentration in the female genital mucosa of cationic polypeptides with reported antiviral activity in relation to DMPA use. Methods:HIV-1–uninfected women were recruited from among couples testing for HIV in Nairobi, Kenya. Cervicovaginal secretion samples were collected, and the concentrations of HNP1–3, LL-37, lactoferrin, HBD-2, and SLPI were measured by enzyme-linked immunosorbent assays. Levels of cationic polypeptides in cervicovaginal secretions were compared between women who were not using hormonal contraception and those using DMPA, oral, or implantable contraception. Results:Among 228 women, 165 (72%) reported not using hormonal contraception at enrollment, 41 (18%) used DMPA, 16 (7%) used an oral contraceptive, and 6 (3%) used a contraceptive implant. Compared with nonusers of hormonal contraception, DMPA users had significantly higher mean levels of HNP1–3 (2.38 vs. 2.04 log10 ng/mL; P = 0.024), LL-37 (0.81 vs. 0.40 log10 ng/mL; P = 0.027), and lactoferrin (3.03 vs. 2.60 log10 ng/mL; P = 0.002), whereas SLPI and HBD-2 were similar. Conclusions:Although all analyzed cationic polypeptides have intrinsic antiviral capacity, their interaction and cumulative effect on female genital mucosa susceptibility to infections in vivo has yet to be unraveled. This study suggests a potential mechanism underlying the effect of DMPA on the innate immune defenses, providing a rationale to investigate its effect on HIV-1 acquisition risk.


Journal of Acquired Immune Deficiency Syndromes | 2016

Changes in vaginal microbiota and immune mediators in HIV-1-seronegative Kenyan women initiating depot medroxyprogesterone acetate

Alison C. Roxby; David N. Fredricks; Katherine Odem-Davis; Kristjana Ásbjörnsdóttir; Linnet Masese; Tina L. Fiedler; Stephen C. De Rosa; Walter Jaoko; James Kiarie; Julie Overbaugh; R. Scott McClelland

Background:Depot medroxyprogesterone acetate (DMPA) is associated with HIV acquisition. We studied changes in vaginal microbiota and inflammatory milieu after DMPA initiation. Methods:In a cohort of HIV-negative Kenyan women, we collected monthly vaginal swabs over 1 year before and after DMPA. Using quantitative polymerase chain reaction, we compared quantities of Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus iners, Gardnerella vaginalis, and total bacterial load (16S ribosomal RNA gene levels). Six vaginal immune mediators were measured with enzyme-linked immunosorbent assay. Trends in the detection and quantity of bacteria were estimated by logistic and linear mixed-effects regression. Results:From 2010 to 2012, 15 HIV-seronegative women initiated DMPA, contributing 85 visits (median, 6 visits/woman; range, 3–8 visits/woman). The median time of DMPA-exposed follow-up was 8.4 months (range, 1.5–11.6 months). Seven women (46%) had bacterial vaginosis within 70 days before DMPA start. L. iners was detected in 13 women (87%) before DMPA start, but other lactobacilli were rarely detected. Gardnerella vaginalis decreased by 0.21 log10 copies per swab per month after DMPA exposure (P = 0.01). Total bacterial load decreased by 0.08 log10 copies per swab per month of DMPA (P = 0.02). Sustained decreases in interleukin (IL)-6 (P = 0.03), IL-8 (P = 0.04), and IL-1 receptor antagonist (P < 0.001) were also noted. Nine women (60%) had L. crispatus detected post-DMPA, which significantly correlated with reduced IL-6 (P < 0.01) and IL-8 (P = 0.02). Conclusions:Initiation of DMPA led to sustained shifts in vaginal bacterial concentrations and levels of inflammatory mediators. Further studies are warranted to outline components of the vaginal microbiota influenced by DMPA use and impact on HIV susceptibility.


PLOS ONE | 2012

Infant safety during and after maternal valacyclovir therapy in conjunction with antiretroviral HIV-1 prophylaxis in a randomized clinical trial.

Alison L. Drake; Alison C. Roxby; James Kiarie; Barbra A. Richardson; Anna Wald; Grace John-Stewart; Carey Farquhar

Background Maternal administration of the acyclovir prodrug valacyclovir is compatible with pregnancy and breastfeeding. However, the safety profile of prolonged infant and maternal exposure to acyclovir in the context of antiretrovirals (ARVs) for prevention of mother-to-child HIV-1 transmission (PMTCT) has not been described. Methods Pregnant Kenyan women co-infected with HIV-1/HSV-2 with CD4 counts > 250 cells/mm3 were enrolled at 34 weeks gestation and randomized to twice daily 500 mg valacyclovir or placebo until 12 months postpartum. Women received zidovudine from 28 weeks gestation and single dose nevirapine was given to women and infants at the time of delivery for PMTCT. Infant blood was collected at 6 weeks for creatinine and ALT. Breast milk specimens were collected at 2 weeks postpartum from 71 women in the valacyclovir arm; acyclovir levels were determined for a random sample of 44 (62%) specimens. Fisher’s Exact and Wilcoxon rank-sum tests were used for analysis. Results One hundred forty-eight women were randomized and 146 mother-infant pairs were followed postpartum. PMTCT ARVs were administered to 98% of infants and all mothers. Valacyclovir was not associated with infant or maternal toxicities or adverse events, and no congenital malformations were observed. Infant creatinine levels were all normal (< 0.83 mg/dl) and median creatinine (median 0.50 mg/dl) and infant growth did not differ between study arms. Acyclovir was detected in 35 (80%) of 44 breast milk samples collected at 2 weeks postpartum. Median and maximum acyclovir levels were 2.62 and 10.15 mg/ml, respectively (interquartile range 0.6–4.19). Conclusions Exposure to PMTCT ARVs and acyclovir after maternal administration of valacyclovir during pregnancy and postpartum to women co-infected with HIV-1/HSV-2 was not associated with an increase in infant or maternal toxicities or adverse events. Trial Registration ClinicalTrials.gov NCT00530777


PLOS ONE | 2011

Herpes Simplex Virus Type 2, Genital Ulcers and HIV-1 Disease Progression in Postpartum Women

Alison C. Roxby; Alison L. Drake; Grace John-Stewart; Elizabeth R. Brown; Daniel Matemo; Phelgona Otieno; Carey Farquhar

Background Co-infection with herpes simplex virus type 2 (HSV-2) has been associated with increased HIV-1 RNA levels and immune activation, two predictors of HIV-1 progression. The impact of HSV-2 on clinical outcomes among HIV-1 infected pregnant women is unclear. Methods HIV-1 infected pregnant women in Nairobi were enrolled antenatally and HSV-2 serology was obtained. HIV-1 RNA and CD4 count were serially measured for 12–24 months postpartum. Survival analysis using endpoints of death, opportunistic infection (OI), and CD4<200 cells µL, and linear mixed models estimating rate of change of HIV-1 RNA and CD4, were used to determine associations between HSV-2 serostatus and HIV-1 progression. Results Among 296 women, 254 (86%) were HSV-2-seropositive. Only 30 (10%) women had prior or current genital ulcer disease (GUD); median baseline CD4 count was 422 cells µL. Adjusting for baseline CD4, women with GUD were significantly more likely to have incident OIs (adjusted hazard ratio (aHR) 2.79, 95% CI: 1.33–5.85), and there was a trend for association between HSV-2-seropositivity and incident OIs (aHR 3.83, 95% CI: 0.93–15.83). Rate of change in CD4 count and HIV-1 RNA did not differ by HSV-2 status or GUD, despite a trend toward higher baseline HIV-1 RNA in HSV-2-seropositive women (4.73 log10 copies/ml vs. 4.47 log10 copies/ml, P = 0.07). Conclusions HSV-2 was highly prevalent and pregnant HIV-1 infected women with GUD were significantly more likely to have incident OIs than women without GUD, suggesting that clinically evident HSV-2 is a more important predictor of HIV-1 disease progression than asymptomatic HSV-2.


Current Hiv\/aids Reports | 2014

A Lifecycle Approach to HIV Prevention in African Women and Children

Alison C. Roxby; Jennifer A. Unger; Jennifer A. Slyker; John Kinuthia; Andrew Lewis; Grace John-Stewart; Judd L. Walson

Effective biomedical and structural HIV prevention approaches are being implemented throughout sub-Saharan Africa. A “lifecycle approach” to HIV prevention recognizes the interconnectedness of the health of women, children and adolescents, and prioritizes interventions that have benefits across these populations. We review new biomedical prevention strategies for women, adolescents and children, structural prevention approaches, and new modalities for eliminating infant HIV infection, and discuss the implications of a lifecycle approach for the success of these methods. Some examples of the lifecycle approach include evaluating education and HIV prevention strategies among adolescent girls not only for their role in reducing risk of HIV infection and early pregnancy, but also to promote healthy adolescents who will have healthier future children. Similarly, early childhood interventions such as exclusive breastfeeding not only prevent HIV, but also contribute to better child and adolescent health outcomes. The most ambitious biomedical infant HIV prevention effort, Option B+, also represents a lifecycle approach by leveraging the prevention benefits of optimal HIV treatment for mothers; maternal survival benefits from Option B+ may have ultimately more health impact on children than the prevention of infant HIV in isolation. The potential for synergistic and additive benefits of lifecycle interventions should be considered when scaling up HIV prevention efforts in sub-Saharan Africa.

Collaboration


Dive into the Alison C. Roxby's collaboration.

Top Co-Authors

Avatar

Carey Farquhar

University of Washington

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

James Kiarie

World Health Organization

View shared research outputs
Top Co-Authors

Avatar

Anna Wald

University of Washington

View shared research outputs
Top Co-Authors

Avatar

John Kinuthia

Kenyatta National Hospital

View shared research outputs
Top Co-Authors

Avatar

Julie Overbaugh

Fred Hutchinson Cancer Research Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Sandra Emery

Fred Hutchinson Cancer Research Center

View shared research outputs
Researchain Logo
Decentralizing Knowledge