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Dive into the research topics where Michael A. Tolle is active.

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Featured researches published by Michael A. Tolle.


Current Problems in Pediatric and Adolescent Health Care | 2009

Mosquito-borne diseases.

Michael A. Tolle

Despite centuries of control efforts, mosquito-borne diseases are flourishing worldwide. With a disproportionate effect on children and adolescents, these conditions are responsible for substantial global morbidity and mortality. Malaria kills more than 1 million children annually, chiefly in sub-Saharan Africa. Dengue virus has expanded its range over the past several decades, following its principal vector, Aedes aegypti, back into regions from which it was eliminated in the mid-20th century and causing widespread epidemics of hemorrhagic fever. West Nile virus has become endemic throughout the Americas in the past 10 years, while chikungunya virus has emerged in the Indian Ocean basin and mainland Asia to affect millions. Japanese encephalitis virus, too, has expanded its range in the Indian subcontinent and Australasia, mainly affecting young children. Filariasis, on the other hand, is on the retreat, the subject of a global eradication campaign. Efforts to limit the effect of mosquito-borne diseases in endemic areas face the twin challenges of controlling mosquito populations and delivering effective public health interventions. Travelers to areas endemic for mosquito-borne diseases require special advice on mosquito avoidance, immunizations, and malaria prophylaxis.


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2013

Evaluation of the effectiveness of an outreach clinical mentoring programme in support of paediatric HIV care scale-up in Botswana

Gelane Workneh; Leah Scherzer; Brianna Kirk; Heather R. Draper; Gabriel Anabwani; R. Sebastian Wanless; Haruna Jibril; Neo Gaetsewe; Boitumelo Thuto; Michael A. Tolle

Abstract Clinical mentoring by providers skilled in HIV management has been identified as a cornerstone of scaling-up antiretroviral treatment in Africa, particularly in settings where expertise is limited. However, little data exist on its effectiveness and impact on improving the quality-of-care and clinical outcomes, especially for HIV-infected children. Since 2008, the Botswana-Baylor Childrens Clinical Centre of Excellence (COE) has operated an outreach mentoring programme at clinical sites around Botswana. This study is a retrospective review of 374 paediatric charts at four outreach mentoring sites (Mochudi, Phutadikobo, Molepolole and Thamaga) evaluating the effectiveness of the programme as reflected in a number of clinically-relevant areas. Charts from one visit prior to initiation of mentoring and from one visit after approximately one year of mentoring were assessed for statistically-significant differences (p<0.05) in the documentation of clinically-relevant indicators. Mochudi showed notable improvements in all indicators analysed, with particular improvements in documentation of pill count, viral load (VL) results, correct laboratory monitoring and correct antiretroviral therapy (ART) dosing (p<0.0001, p<0.0001, p<0.0001 and p<0.0001, respectively). Broad and substantial improvements were also seen in Molepolole, with the most improvement in disclosure documentation of all four sites. At Thamaga, improvements were restricted to CD4 documentation (p<0.001), recent VL and documented pill count (p<0.05 and p<0.05, respectively). Phuthadikobo showed the least amount of improvement across indicators, with only VL documentation and correct ART dosing showing statistically-significant improvements (p<0.05 and p<0.0001, respectively). These findings suggest that clinical mentoring may assist improvements in a number of important areas, including ART dosing and monitoring; adherence assessment and assurance; and disclosure. Clinical mentoring may be a valuable tool in scale-up of quality paediatric HIV care-and-treatment outside specialised centres. Further study will help refine approaches to clinical mentoring, including assuring mentoring translates into improved clinical outcomes for HIV-infected children.


American Journal of Tropical Medicine and Hygiene | 2011

Prevalence of Hepatitis B and Hepatitis C Coinfections in an Adult HIV Centre Population in Gaborone, Botswana

Premal Patel; Stephanie Davis; Michael A. Tolle; Vincent Mabikwa; Gabriel Anabwani

The objective of this study was to assess the prevalence of hepatitis B and hepatitis C coinfections in human immunodeficiency virus (HIV) -infected adults at an HIV center in Gaborone, Botswana. A retrospective review was performed of charts of currently active HIV-infected adult patients in the Family Model Clinic (FMC) of the Botswana-Baylor Childrens Clinical Center of Excellence (BCOE) in Gaborone, Botswana, for the results of serum hepatitis B surface antigen (HBsAg) and antihepatitis C IgG tests performed between January 1, 2005 and December 15, 2009. Of 308 active FMC patients, 266 underwent HBsAg serology testing within the period of study. The HBsAg coinfection prevalence was 5.3% (14/266); 2 of 252 patients had at least one positive antihepatitis C IgG serology, a 0.8% prevalence. Hepatitis B coinfection is relatively common in HIV-infected adults at our center in Botswana, whereas hepatitis C coinfection is rare. In this setting, where the diagnosis of hepatitis B coinfection with HIV has implications for choice of first-line antiretroviral therapy and prevention of perinatal hepatitis B transmission, broader sampling to establish the true population prevalence of hepatitis B coinfection and the desirability of adding screening to HIV management should be considered. These findings provide little justification for adding hepatitis C coinfection screening to the management of HIV infection in Botswana.


Tropical Medicine & International Health | 2009

A package of primary health care services for comprehensive family-centred HIV/AIDS care and treatment programs in low-income settings

Michael A. Tolle

Particularly in resource‐limited settings, HIV/AIDS is a family concern. Separate services for children and adults may make accessing care more difficult for families than services where family members can be cared for together. Implicit in comprehensive, family‐centred approaches to care are the broader notions of longitudinal primary care and linkages to other services, including those based in communities. As highly‐active antiretroviral therapy becomes more available, and the direct burden of HIV‐associated morbidity diminishes, HIV‐infected individuals require primary care that goes beyond exclusive management of HIV and related conditions, including preventive services and the management of common medical issues. The prevention of tuberculosis, diarrhoea, and, in endemic regions, malaria; the addressing of debilitating depression; cervical screening; and the management of chronic cardiovascular disease and its risk factors are all of benefit to patients accessing HIV/AIDS care. Packaging such services is an effective means both of standardizing care within a program and of ensuring patients receives a full roster of available interventions. As family‐centred care models develop in resource‐limited settings, the availability of evidence‐based service packages such as presented here will help program designers prioritize available human and materiel resources toward those interventions that improve patients’ global health and well being.


South African Medical Journal | 2012

HIV management by nurse prescribers compared with doctors at a paediatric centre in Gaborone, Botswana

Gadzikanani Monyatsi; Paul C Mullan; Benjamin R. Phelps; Michael A. Tolle; Edwin M Machine; Floriza F Gennari; Jenny Makosky; Gabriel M Anabwani

OBJECTIVES To compare compliance with national paediatric HIV treatment guidelines between nurse prescribers and doctors at a paediatric referral centre in Gaborone, Botswana. METHODS A cross-sectional study was conducted in 2009 at the Botswana-Baylor Childrens Clinical Centre of Excellence (COE), Gaborone, Botswana, comparing the performance of nurse prescribers and physicians caring for HIV-infected paediatric patients. Selected by stratified random sampling, 100 physician and 97 nurse prescriber encounters were retrospectively reviewed for successful documentation of eight separate clinically relevant variables: pill count charted; chief complaint listed; social history updated; disclosure reviewed; physical exam; laboratory testing; World Health Organization (WHO) staging documented; paediatric dosing. RESULTS Nurse prescribers and physicians correctly documented 96.0% and 94.9% of the time, respectively. There was a trend towards a higher proportion of social history documentation by the nurses, but no significant difference in any other documentation items. CONCLUSIONS Our findings support the continued investment in programmes employing properly trained nurses in southern Africa to provide quality care and ART services to HIV-infected children who are stable on therapy. Task shifting remains a promising strategy to scale up and sustain adult and paediatric ART more effectively, particularly where provider shortages threaten ART rollout. Policies guiding ART services in southern Africa should avoid restricting the delivery of crucial services to doctors, especially where their numbers are limited.


PLOS ONE | 2015

Vitamin D₃ Supplementation in Batswana Children and Adults with HIV: A Pilot Double Blind Randomized Controlled Trial

Andrew P. Steenhoff; Joan I. Schall; Julia L. Samuel; Boitshepo Seme; Marape Marape; Bakgaki Ratshaa; Irene Goercke; Michael A. Tolle; Maria Nnyepi; Loeto Mazhani; Babette S. Zemel; Richard M. Rutstein; Virginia A. Stallings

Objectives Since vitamin D insufficiency is common worldwide in people with HIV, we explored safety and efficacy of high dose cholecalciferol (D₃) in Botswana, and evaluated potential modifiers of serum 25 hydroxy vitamin D change (Δ25D). Design Prospective randomized double-blind 12-week pilot trial of subjects ages 5.0–50.9 years. Methods Sixty subjects randomized within five age groups to either 4000 or 7000IU per day of D₃ and evaluated for vitamin D, parathyroid hormone, HIV, safety and growth status. Efficacy was defined as serum 25 hydroxy vitamin D (25D) ≥32ng/mL, and safety as no simultaneous elevation of serum calcium and 25D. Also assessed were HIV plasma viral RNA viral load (VL), CD4%, anti-retroviral therapy (ART) regime, and height-adjusted (HAZ), weight-adjusted (WAZ) and Body Mass Index (BMIZ) Z scores. Results Subjects were 50% male, age (mean±SD) 19.5±11.8 years, CD4% 31.8±10.4, with baseline VL log₁₀ range of <1.4 to 3.8 and VL detectable (>1.4) in 22%. From baseline to 12 weeks, 25D increased from 36±9ng/ml to 56±18ng/ml (p<0.0001) and 68% and 90% had 25D ≥32ng/ml, respectively (p = 0.02). Δ25D was similar by dose. No subjects had simultaneously increased serum calcium and 25D. WAZ and BMIZ improved by 12 weeks (p<0.04). HAZ and CD4% increased and VL decreased in the 7000IU/d group (p<0.04). Younger (5–13y) and older (30–50y) subjects had greater Δ25D than those 14–29y (26±17 and 28±12 vs. 11±11ng/ml, respectively, p≤0.001). Δ25D was higher with efavirenz or nevirapine compared to protease inhibitor based treatment (22±12, 27±17, vs. 13±10, respectively, p≤0.03). Conclusions In a pilot study in Botswana, 12-week high dose D₃ supplementation was safe and improved vitamin D, growth and HIV status; age and ART regimen were significant effect modifiers. Trial Registration ClinicalTrials.gov NCT02189902


Journal of The International Association of Physicians in Aids Care (jiapac) | 2012

Reverse Transcriptase Genotypes in Pediatric Patients Failing Initial Antiretroviral Therapy in Gaborone, Botswana

Michael A. Tolle; Leigh Howard; Brianna Kirk; Andres Gomila; Heidi Schwarzwald; Gabriel Anabwani

Background Limited data are available on patterns of resistance mutations in pediatric patients in southern Africa, where HIV-1 subtype C (HIV-1C) predominates. Methods Retrospective chart review of pediatric patients. Nucleoside reverse transcriptase inhibitor (NRTI)- and nonnucleoside reverse transcriptase inhibitor (NNRTI)-associated resistance mutations quantified from population-based sequencing genotypic resistance assay results taken at time of first-line antiretroviral therapy (ART) failure (first-line ART = stavudine [d4T] or zidovudine [ZDV] + lamivudine [3TC] + nevirapine [NVP] or efavirenz [EFV]). Results Total number of patients with resistance assays analyzed is 45. Nucleoside reverse transcriptase inhibitor-associated mutation frequencies noted were M184V (n = 41; 91.1%); thymidine analogue mutations (TAMs; n = 20; 44.4%); >1 TAM (n = 9; 20%); TAM-2 pathway (n = 10; 22.2%); TAM-1 pathway (n = 7; 15.6%); TAM-1 and TAM-2 pathways (n = 3; 6.7%); K65R (n = 2; 4.4%); Q151M (n = 1; 2.2%); and L74V (n = 0; 0%). Nonnucleoside reverse transcriptase inhibitor-associated mutation frequencies noted were associated with notable resistance to either/both NVP and EFV (n = 40; 88.9%); K103N (n = 15; 33.3%); ≥1 mutations associated with etravirine (ETR) failure (K101E, Y181C, and G190A; n =20; 44.4%); and ≥2 notable NNRTI mutations (n = 12; 26.7%). Conclusions In this cohort, low-genetic barrier mutations were common, as were TAMs, including more than 1 TAM. Mutations compromising nonthymidine analogue backbones were rare, suggesting that it is likely that children who fail first-line NRTI backbones containing d4T or ZDV/3TC would still respond to abacavir (ABC), didanosine (ddI), and, for adolescents, tenofovir (TDF). Our data support the empiric continuation of 3TC in second-line regimens.


Journal of the International Association of Providers of AIDS Care | 2013

Early Outcomes of Darunavir- and/or Raltegravir-Based Antiretroviral Therapy in Children with Multidrug-Resistant HIV at a Pediatric Center in Botswana

Brianna Kirk; Andres Gomila; Marape Marape; Dipesalema Joel; Gabriel Anabwani; Michael A. Tolle

Background: Data on the use of ritonavir-boosted darunavir (DRV/r) and/or raltegravir (RAL) in resource-limited settings are rare and there is currently no published data regarding their use among African children. Botswana has recently made DRV/r and RAL available for patients failing second-line antiretroviral therapy (ART). Methods: Retrospective chart review of 4 multidrug-resistant pediatric patients on DRV/r- and/or RAL-based regimens. Viral load, CD4 count, adherence by pill count, and World Health Organization (WHO) clinical stage prior to and after switch to DRV/r- and/or RAL-based regimen were assessed. Antiretroviral therapy history, duration of virologic failure, and time to viral suppression were also noted. Genotypic resistance assays reviewed for mutations present prior to switch. Results: All patients achieved viral suppression, showed improved/stable CD4 counts, and obtained or maintained WHO clinical treatment stage I, even after long-standing virologic/immunologic failure. Conclusions: Well tolerated by and effective in our patients, DRV/r and RAL provide potentially lifesaving ART options for children and adolescents in resource-limited settings failing ART due to ritonavir-boosted lopinavir (LPV/r) resistance.


AIDS | 2013

Delivering pediatric HIV care in resource-limited settings: cost considerations in an expanded response

Michael A. Tolle; B. Ryan Phelps; Chris Desmond; Nandita Sugandhi; Chinyere Omeogu; David Jamieson

If children are to be protected from HIV, the expansion of PMTCT programs must be complemented by increased provision of paediatric treatment. This is expensive, yet there are humanitarian, equity and childrens rights arguments to justify the prioritization of treating HIV-infected children. In the context of limited budgets, inefficiencies cost lives, either through lower coverage or less effective services. With the goal of informing the design and expansion of efficient paediatric treatment programs able to utilize to greatest effect the available resources allocated to the treatment of HIV-infected children, this article reviews what is known about cost drivers in paediatric HIV interventions, and makes suggestions for improving efficiency in paediatric HIV programming. High-impact interventions known to deliver disproportional returns on investment are highlighted and targeted for immediate scale-up. Progress will carry a cost - increased funding, as well as additional data on intervention costs and outcomes, will be required if universal access of HIV-infected children to treatment is to be achieved and sustained.


International Journal of Tuberculosis and Lung Disease | 2014

Diagnosis of paediatric tuberculosis using sputum induction in Botswana: programme description and findings.

D R Joel; Andrew P. Steenhoff; Paul C. Mullan; Benjamin R. Phelps; Michael A. Tolle; Ari Ho-Foster; Mabikwa; B G Kgathi; R Ncube; Gabriel M. Anabwani

SETTING Four public hospitals in Botswana, a high tuberculosis (TB) burden setting. OBJECTIVES To assess the feasibility and utility of sputum induction in the diagnosis of paediatric TB. DESIGN From 2008 to 2010, children aged ≤18 years referred for suspected pulmonary TB underwent sputum induction. Confirmed TB was defined as the presence of at least one of the signs and symptoms suggestive of TB and positive Mycobacterium tuberculosis culture. Information on TB-associated symptoms (cough, fatigue, night sweats, low appetite, chest pain, weight loss, haemoptysis and contact with a TB case) was collected for three risk groups: human immunodeficiency virus (HIV) positive children, HIV-negative children aged <3 years and HIV-negative children aged ≥3 years. RESULTS The median age of the 1394 subjects who underwent sputum induction was 3.8 years (IQR 1.3-8.4); 373 (27%) were HIV-positive, 419 (30%) were HIV-negative and 602 (43%) had unknown HIV status. TB was confirmed in 84 (6.0%); cases were more likely to have weight loss, chest pain or TB household contacts. There were no serious complications attributable to sputum induction during and after the procedure; only 0.8% (9/1174) of patients reported minor complications. CONCLUSIONS In Botswana, paediatric sputum induction was feasible, safe and assisted bacteriological confirmation in a subgroup of children treated for TB.

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Brianna Kirk

Baylor College of Medicine

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Premal Patel

University of Texas Medical Branch

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Andres Gomila

Baylor College of Medicine

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Andrew P. Steenhoff

Children's Hospital of Philadelphia

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Ari Ho-Foster

University of Pennsylvania

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