BLOOD PRESSURE TRAJECTORIES AND MORTALITY AMONG PEOPLE WITH AND WITHOUT HIV IN A UNITED STATES-BASED COHORT STUDY

Background: With the uptake and efficacy of antiretroviral therapy (ART), people with HIV are living longer and experiencing an increasing burden of chronic diseases and comorbidities, including high blood pressure. High blood pressure is the leading cause of morbidity and mortality worldwide, meaning it may be a promising avenue to reduce morbidity and mortality among people with HIV. The mechanism between HIV and blood pressure is not well understood, though chronic inflammation and immune activation are implicated in both HIV infection and high blood pressure. Thus, it is possible that people with HIV on ART can experience 1) larger changes in blood pressure over time and 2) higher rates of adverse outcomes (e.g., clinical events) associated with high blood pressure than people without HIV. However, blood pressure and its consequences are not well characterized among people with HIV.Methods: We used data from the Multicenter AIDS Cohort Study (MACS) and Women’s Interagency HIV Study (WIHS). Among people with HIV who report use of ART as well as people without HIV, we described blood pressure trajectories between ages 20 and 70 years (Aim 1). We also estimate the association between systolic blood pressure and all-cause mortality among people with HIV reporting use of ART and people without HIV (Aim 2).Results: Estimated blood pressure trajectories were similar between men with and without HIV. Blood pressure was slightly lower for women with HIV compared to those without at most ages. Trajectories for all groups aligned with previously published trajectories in the general population. Having a systolic blood pressure between 110 and 130 mm Hg (i.e., within the systolic target range) was more strongly associated with reduced mortality among people with HIV than people without HIV. The hazard of all-cause mortality declined with increasing time in the systolic target range.Conclusions: People with HIV did not experience notably different blood pressure trajectories than demographically similar people without HIV. Sustained blood pressure control in this population was associated with a lower hazard of all-cause mortality. Both findings highlight the importance of understanding the unique intersection of HIV cardiometabolic diseases such as high blood pressure.Doctor of Philosoph

Quantitative Evidence for the Effects of Multiple Drivers on Continental-Scale Amphibian Declines

Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a “smoking gun” was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased local extinction risk, evidence for effects of these drivers is lacking at large spatial scales. Here, we use observations of 389 time-series of 83 species and complexes from 61 study areas across North America to test the effects of 4 of the major hypothesized drivers of declines. While we find that local amphibian populations are being lost from metapopulations at an average rate of 3.79% per year, these declines are not related to any particular threat at the continental scale; likewise the effect of each stressor is variable at regional scales. This result - that exposure to threats varies spatially, and populations vary in their response - provides little generality in the development of conservation strategies. Greater emphasis on local solutions to this globally shared phenomenon is needed

Quantitative Evidence for the Effects of Multiple Drivers on Continental-Scale Amphibian Declines

Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a “smoking gun” was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased local extinction risk, evidence for effects of these drivers is lacking at large spatial scales. Here, we use observations of 389 time-series of 83 species and complexes from 61 study areas across North America to test the effects of 4 of the major hypothesized drivers of declines. While we find that local amphibian populations are being lost from metapopulations at an average rate of 3.79% per year, these declines are not related to any particular threat at the continental scale; likewise the effect of each stressor is variable at regional scales. This result - that exposure to threats varies spatially, and populations vary in their response - provides little generality in the development of conservation strategies. Greater emphasis on local solutions to this globally shared phenomenon is needed

Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals

Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth’s crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O− in a matrix of O2−. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth’s surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L’Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals

Hypertension and one-year risk of all-cause mortality among women with treated HIV in the United States

Objective: Hypertension is a critical cause of cardiovascular disease, and women with HIV have a higher prevalence of hypertension than women without HIV. The relationship between hypertension and mortality has not been well characterized in women with treated HIV. Here, we estimate the effect of hypertension on 1-year risk of all-cause mortality among women with HIV on antiretroviral therapy (ART) in the United States. Design: An analysis of multicenter, observational cohort data from the Women's Interagency HIV Study (WIHS) collected between 1995 and 2019. Methods: We included women with HIV who reported ever using ART. We used parametric g-computation to estimate the effect of hypertension (SBP ≥140 mmHg, DBP ≥90 mmHg, or use of hypertensive medication) on all-cause mortality within 1 year of a WIHS visit. Results: Among 2929 unique women, we included 57 034 visits with a median age of 45 (interquartile range: 39, 52) years. Women had hypertension at 34.5% of visits, and 641 deaths occurred within 1 year of a study visit. Comparing women at visits with hypertension to women at visits without hypertension, the standardized 1-year risk ratio for mortality was 1.16 [95% confidence interval (95% CI): 1.01-1.33]. The risk ratios were higher in Hispanic (risk ratio: 1.23, 95% CI: 0.86-1.77) and non-Hispanic black women (risk ratio: 1.19, 95% CI: 1.04-1.37) and lower in non-Hispanic white women (risk ratio: 0.93, 95% CI: 0.58-1.48). Conclusion: Among women with treated HIV, those with hypertension, compared with those without, had an increased 1-year risk of all-cause mortality

Do Frogs Get Their Kicks on Route 66? Continental U.S. Transect Reveals Spatial and Temporal Patterns of Batrachochytrium dendrobatidis Infection

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been devastating amphibians globally. Two general scenarios have been proposed for the nature and spread of this pathogen: Bd is an epidemic, spreading as a wave and wiping out individuals, populations, and species in its path; and Bd is endemic, widespread throughout many geographic regions on every continent except Antarctica. To explore these hypotheses, we conducted a transcontinental transect of United States Department of Defense (DoD) installations along U.S. Highway 66 from California to central Illinois, and continuing eastward to the Atlantic Seaboard along U.S. Interstate 64 (in sum from Marine Corps Base Camp Pendleton in California to Naval Air Station Oceana in Virginia). We addressed the following questions: 1) Does Bd occur in amphibian populations on protected DoD environments? 2) Is there a temporal pattern to the presence of Bd? 3) Is there a spatial pattern to the presence of Bd? and 4) In these limited human-traffic areas, is Bd acting as an epidemic (i.e., with evidence of recent introduction and/or die-offs due to chytridiomycosis), or as an endemic (present without clinical signs of disease)? Bd was detected on 13 of the 15 bases sampled. Samples from 30 amphibian species were collected (10% of known United States' species); half (15) tested Bd positive. There was a strong temporal (seasonal) component; in total, 78.5% of all positive samples came in the first (spring/early-summer) sampling period. There was also a strong spatial component—the eleven temperate DoD installations had higher prevalences of Bd infection (20.8%) than the four arid (<60 mm annual precipitation) bases (8.5%). These data support the conclusion that Bd is now widespread, and promote the idea that Bd can today be considered endemic across much of North America, extending from coast-to-coast, with the exception of remote pockets of naïve populations

Seasonal Pattern of Batrachochytrium dendrobatidis Infection and Mortality in Lithobates areolatus: Affirmation of Vredenburg's “10,000 Zoospore Rule”

To fully comprehend chytridiomycosis, the amphibian disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), it is essential to understand how Bd affects amphibians throughout their remarkable range of life histories. Crawfish Frogs (Lithobates areolatus) are a typical North American pond-breeding species that forms explosive spring breeding aggregations in seasonal and semipermanent wetlands. But unlike most species, when not breeding Crawfish Frogs usually live singly—in nearly total isolation from conspecifics—and obligately in burrows dug by crayfish. Crayfish burrows penetrate the water table, and therefore offer Crawfish Frogs a second, permanent aquatic habitat when not breeding. Over the course of two years we sampled for the presence of Bd in Crawfish Frog adults. Sampling was conducted seasonally, as animals moved from post-winter emergence through breeding migrations, then back into upland burrow habitats. During our study, 53% of Crawfish Frog breeding adults tested positive for Bd in at least one sample; 27% entered breeding wetlands Bd positive; 46% exited wetlands Bd positive. Five emigrating Crawfish Frogs (12%) developed chytridiomycosis and died. In contrast, all 25 adult frogs sampled while occupying upland crayfish burrows during the summer tested Bd negative. One percent of postmetamorphic juveniles sampled were Bd positive. Zoospore equivalents/swab ranged from 0.8 to 24,436; five out of eight frogs with zoospore equivalents near or >10,000 are known to have died. In summary, Bd infection rates in Crawfish Frog populations ratchet up from near zero during the summer to over 25% following overwintering; rates then nearly double again during and just after breeding—when mortality occurs—before the infection wanes during the summer. Bd-negative postmetamorphic juveniles may not be exposed again to this pathogen until they take up residence in crayfish burrows, or until their first breeding, some years later