A5013892545- COVID-19 epidemiological studies
- Viral Infections and Outbreaks Research
- HIV/AIDS Research and Interventions
- HIV, Drug Use, Sexual Risk
- HIV Research and Treatment
- Mosquito-borne diseases and control
- Zoonotic diseases and public health
- Vaccine Coverage and Hesitancy
- Viral Infections and Vectors
- Evolution and Genetic Dynamics
- SARS-CoV-2 and COVID-19 Research
- Yersinia bacterium, plague, ectoparasites research
- Wildlife Ecology and Conservation
- Bacillus and Francisella bacterial research
- Virology and Viral Diseases
- Adolescent Sexual and Reproductive Health
- Hepatitis B Virus Studies
- HIV/AIDS drug development and treatment
- HIV-related health complications and treatments
- Animal Disease Management and Epidemiology
- Data-Driven Disease Surveillance
- Ethics and Legal Issues in Pediatric Healthcare
- Microbial Inactivation Methods
- Wildlife-Road Interactions and Conservation
- Control Systems and Identification
University of Georgia
2016-2019
Stellenbosch University
2016-2019
The University of Texas at Austin
2013-2016
University of Padua
2015
University of California, Berkeley
2010-2014
Nearly all mathematical models of vector-borne diseases have assumed that vectors die at constant rates. However, recent empirical research suggests mosquito mortality rates are frequently age dependent. This work develops a simple model to assess how relaxing the classical assumption affects predicted effectiveness anti-vectorial interventions. The control when mosquitoes dependent was also compared across different extrinsic incubation periods. Compared more realistic model, overestimated...
The recent development of genetic markers for Bacillus anthracis has made it possible to monitor the spread and distribution this pathogen during between anthrax outbreaks. In Namibia, outbreaks occur annually in Etosha National Park (ENP) on private game livestock farms. We genotyped 384 B. isolates collected 1983–2010 identify epidemiological correlations within outside ENP analyze relationships from domestic wild animals. came 20 animal species environment were using a 31-marker...
Background The infectivity of the HIV-1 acute phase has been directly measured only once, from a retrospectively identified cohort serodiscordant heterosexual couples in Rakai, Uganda. Analyses this underlie widespread view that is highly infectious, even more so than would be predicted its elevated viral load, and transmission occurring shortly after infection may therefore compromise interventions rely on diagnosis treatment, such as antiretroviral treatment prevention (TasP). Here, we...
Interventions in infectious diseases can have both direct effects on individuals who receive the intervention as well indirect population. In addition, combinations complex interactions at population level, which are often difficult to adequately assess with standard study designs and analytical methods. Herein, we urge adoption of a new paradigm for design interpretation trials diseases, particularly regard emerging one that more accurately reflects dynamics transmission process. an...
Summary Few studies have examined host‐pathogen interactions in wildlife from an immunological perspective, particularly the context of seasonal and longitudinal dynamics. In addition, though most ecological immunology employ serological antibody assays, endpoint titre determination is usually based on subjective criteria needs to be made more objective. Despite fact that anthrax ancient emerging zoonotic infectious disease found world‐wide, its natural ecology not well understood....
Confirmed local transmission of Zika Virus (ZIKV) in Texas and Florida have heightened the need for early accurate indicators self-sustaining high risk areas across southern United States. Given ZIKV's low reporting rates geographic variability suitable conditions, a cluster reported cases may reflect diverse scenarios, ranging from independent introductions to epidemic.We present quantitative framework real-time ZIKV assessment that captures uncertainty case reporting, importations,...
Canine distemper virus (CDV) and rabies (RABV) occur worldwide in wild carnivore domestic dog populations pose threats to wildlife conservation public health. In Etosha National Park (ENP), Namibia, anthrax is endemic generates carcasses frequently fed on by an unusually dense population of black-backed jackals (Canis mesomelas). Using serology, phylogenetic analyses (on samples obtained from February 2009–July 2010), historical mortality records (1975–2011), we assessed jackal exposure...
Scavenging of anthrax carcasses has long been hypothesized to play a critical role in the production infectious spore stage Bacillus anthracis after host death, though empirical studies assessing this are lacking. We compared B. production, distribution, and survival at naturally occurring herbivore that were either experimentally caged exclude vertebrate scavengers or left unmanipulated. found no significant effect on soil density (P > 0.05). Soil stained with terminally hemorrhaged blood...
Poor adherence to either antiretroviral treatment (ART) or pre-exposure prophylaxis (PrEP) can promote drug resistance, though this risk is thought be considerably higher for ART. In the population of men who have sex with (MSM) in San Francisco, PrEP coverage reached 9.6% 2014 and has continued rise. Given resistance high cost second-line drugs, costs benefits initiating ART earlier while expanding remain unclear. We develop an infection–age-structured mathematical model fit annual...
Abstract Scat analysis is one of the most frequently used methods to assess carnivoran diets, and global positioning system ( GPS ) cluster are increasingly being locate feeding sites for large carnivorans. However, both have inherent biases that limit their use. kill biased towards carcasses, while scat overestimates biomass consumed from smaller prey. We combined carcass observations scats collected along known movement routes, assessed using data four A frican lion P anthera leo prides in...
Distance sampling is widely used to estimate the abundance or density of wildlife populations. Methods mortality rates have developed largely independently from distance sampling, despite conceptual similarities between estimation cumulative and population living animals. Conventional analyses rely on assumption that animals are distributed uniformly with respect transects thus require randomized placement during survey design. Because events rare, however, it often not possible obtain...
Vaccine efficacy against susceptibility to infection (VES), regardless of symptoms, is an important endpoint vaccine trials for pathogens with a high proportion asymptomatic infection, because such infections may contribute onward transmission and long-term sequelae, as congenital Zika syndrome. However, estimating VES resource-intensive. We aimed identify approaches accurately when limited information available resources are constrained. modeled individually randomized trial by generating...
Power considerations for trials evaluating vaccines against infectious diseases are complicated by indirect protective effects of vaccination. While cluster-randomized controlled (cRCTs) less statistically efficient than individually randomized (iRCTs), a cRCT's ability to measure direct and vaccine may mitigate the loss efficiency due clustering. Within cRCTs, number size clusters affects 3 determinants power: effect being measured, disease incidence, intracluster correlation. We simulated...
Animals share a variety of common resources, which can be major driver conspecific encounter rates. In this work, we implement spatially explicit mathematical model for resource visitation behaviour in order to examine how changes availability influence the rate encounters among consumers. Using simulations and asymptotic analysis, demonstrate that, under reasonable set assumptions, relationship between consumer is not monotonic. We characterize maximum associated critical density depend on...
Objective New guidelines recommend that all HIV-infected individuals initiate antiretroviral treatment (ART) immediately following diagnosis. This study describes how immune reconstitution varies by gender and age to help identify poorly reconstituting subgroups inform targeted testing initiatives. Design Longitudinal data from the outpatient monitoring system of National AIDS Control Program in Tanzania. Methods An asymptotic nonlinear mixed effects model was fit post-treatment CD4+ cell...
Recent studies have evaluated cumulative human immunodeficiency virus type 1 (HIV-1) viral load (cVL) for predicting disease outcomes, with discrepant results. We reviewed the disparate methodological approaches taken and prognostic utility of cVL in a resource-limited setting. Using data on Infectious Diseases Institute (Makerere University, Kampala, Uganda) cohort, who initiated antiretroviral therapy 2004–2005 were followed up 9 years, we calculated patients' time-updated by summing area...
Modern infectious disease epidemiology builds on two independently developed fields: classical and dynamical epidemiology. Over the past decade, integration of fields has increased in research practice, but training options within remain distinct with few opportunities for classroom. The annual Clinic Meaningful Modeling Epidemiological Data (MMED) at African Institute Mathematical Sciences begun to address this gap. MMED offers participants exposure a broad range concepts techniques from...
Early initiation of antiretroviral therapy (ART) reduces the risk drug-sensitive HIV transmission but may increase drug-resistant HIV. We used a mathematical model to estimate long-term population-level benefits ART and determine scenarios under which earlier (treatment at 1 year post-infection, on average) could decrease simultaneously both total incidence (new infections). constructed an infection-age-structured that tracked rates over course infection modelled patients' life expectancy as...
Licensed vaccines are urgently needed for emerging infectious diseases, but the nature of these epidemics causes challenges design phase III trials to evaluate vaccine efficacy. Designing and executing rigorous, fast, ethical, efficacy is difficult, decisions limitations in encompass epidemiological, logistical, regulatory, statistical, ethical dimensions.
As emerging and re-emerging infectious arboviruses like dengue, chikungunya, Zika threaten new populations worldwide, officials scramble to assess local severity transmissibility, with little no epidemiological history draw upon. Indirect estimates of risk from vector habitat suitability maps are prone great uncertainty, while direct data only possible after cases accumulate and, given environmental constraints on arbovirus transmission, cannot be widely generalized beyond the focal region....