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Background Testing for high-risk human papillomavirus (HPV) infection using mailed, self-collected samples is a promising approach to increase screening in women who do not attend clinic screening at recommended intervals. Methods To assess this intervention among high-risk women in the United States, 429 women without a Papanicolaou (Pap) test in 4 or more years (overdue by US guidelines) were recruited from the general population. Participants aged 30 to 65 years were mailed a kit to self-collect a cervicovaginal sample at home, return the sample by mail, and receive HPV results by telephone, with referral to follow-up cytological Pap testing at a local clinic. Cervicovaginal self-samples were collected with a Viba brush, stored in Scope mouthwash, and tested by Hybrid Capture 2. Data were collected in 2010 to 2011 and analyzed in 2017. Results Two-thirds (64%) of participants returned a self-collected sample, of whom 15% tested HPV DNA positive. Human papillomavirus self-test-positive women reported higher rates of follow-up Pap tests (82%) than did those with self-test negative results (51%). No demographic differences were found in self-test return rate or HPV positivity. High acceptability was reported in participant surveys: most women (81%) had "mostly positive" overall thoughts about the self-test, and most reported being comfortable receiving the kit in the mail (99%), returning their self-collected sample by mail (82%), and receiving their test results by telephone (97%). Conclusions Conducting HPV self-testing through population-based recruitment, mailed kit delivery and return by mail, and results delivery by telephone has the potential to reach a broad segment of US underscreened women.

Leprosy (or Hansen’s disease) remains an important public health challenge globally, with an estimated 5.5 million total number of cases and 200,000–300,000 new cases reported annually. The nine-banded armadillo (Dasypus novemcinctus) is the only known natural non-human vertebrate host of Mycobacterium leprae, the causative agent of leprosy, in the Americas, yet gaps in knowledge remain regarding the dynamics of leprosy in wild populations. Here, we used data from a six-year study of a population of armadillos in Mississippi, USA to quantify the influence of leprosy on armadillo population dynamics, and to investigate leprosy dynamics within the host population. Leprosy reduced annual survival of adult armadillos by ∼15%, and growth rate of the population by ∼13%. The annual infection rate for adult armadillos (i.e., probability that a non-leprous adult armadillo seroconverts, conditional on survival) was 0.18, with no possibility of recovery. Assuming frequency-dependent transmission of leprosy, 18% to 25% of the adult armadillos will acquire leprosy infection in the long run. Finally, the basic reproductive ratio (R0) was 1.36, suggesting 36% increase in seroprevalence per leprosy generation. Assuming that leprosy generation time is 3–5 years, M. leprae will spread within the armadillo population at the rate of 7–12% per year. Our results are consistent with recent evidence that leprosy infection in armadillos in the USA is spreading rapidly with a concomitant increase in risk for zoonotic transmissions.

We used 15 years (1992–2006) of capture–mark–recapture (CMR) data obtained from a population of nine-banded armadillos (Dasypus novemcinctus) located at the Tall Timbers Research Station near Tallahassee, Florida and multistate CMR models to estimate and model capture probabilities, annual apparent survival, and transition probabilities between reproductive and nonreproductive states (for adult females only). Using an information theoretic approach, we then examined various influences on these parameters. Across all years, capture probability, p, was higher for adults than for yearlings, and higher for males than for females. There was also substantial yearly variation. Conditional on survival, the annual transition probability, ψ, for reproductive adult females to remain reproductive was 0.853 ± 0.044; the estimate for nonreproductive adult females to become reproductive was 0.388 ± 0.060. Annual apparent survival, S, was lowest for juveniles (S = 0.541 ± 0.118) and highest for reproductive adul...

Interventions to mitigate household air pollution (HAP) from cooking with solid fuels often fail to take into account the role of access to freely available woodfuels in determining fuel choice and willingness to adopt clean cooking technologies, key factors in mitigating the burden of HAP. We use national-scale remote sensing data on land use land cover change, and population representative data from two waves of the Malawi Living Standards Measurement Survey to explore the relationship between land use change and the type of fuel households use, time spent collecting fuel, and expenditures on fuel, hypothesizing that land use dynamics influence household-level choice of primary cooking fuel. We find considerable heterogeneity with respect to regeneration and deforestation/degradation dynamics and evidence of spatial clustering. We find that regeneration of forests and woodlands increases the share of households that collect fuelwood, whereas deforestation and degradation lead households to purchase fuelwood. We also find that relatively large share of land under woody savannah or degraded forest (vs. fully stocked forest) increases fuel collection time. Areas with regeneration happening at broader scale experience increases in fuel expenditures. Our findings have implications for the spatial targeting of interventions designed to mitigate household air pollution.

The Gopher Tortoise (Gopherus polyphemus) is a keystone species whose burrowing activities are of critical importance for upland ecosystems. Perhaps no age class is as enigmatic or vulnerable as hatchlings, and understanding the survival dynamics of hatchlings is critical for the parameterization of population viability models that will help guide adaptive management of this threatened species. Meta-analysis is a particularly useful technique for integrating results of published studies that provide different estimates of a single parameter of interest. A summary value from multiple studies could therefore provide a more representative estimate of a vital rate across heterogeneous study populations. We estimated hatchling survivorship from a natural population in North Florida using hatchling cohorts from a 3-yr telemetry study. To provide continuous estimates of survival through time, we fit weekly telemetry data to Weibull survival curves. We then incorporated the least biased estimate of hatch...

Despite a heightened interest regarding the role of infectious diseases in wildlife conservation, few studies have explicitly addressed the impacts of chronic, persistent diseases on long-term host population dynamics. Using mycoplasmal upper respiratory tract disease (URTD) within natural gopher tortoise Gopherus polyphemus populations as a model system, we investigated the influence of chronic recurring disease epizootics on host population dynamics and persistence using matrix population models and Markov chain models for temporally autocorrelated environments. By treating epizootics as a form of environmental stochasticity, we evaluated host population dynamics across varying levels of outbreak duration (r), outbreak recurrence (f ), and disease-induced mortality (m). Baseline results indicated a declining growth rate (l) for populations under unexposed or enzootic conditions (lEnzootic  0.903, 95% CI: 0.765–1.04), and a median time to quasiextinction of 29 years (range: 28–30 years). Under recurring epizootics, stochastic growth rates overlapped with baseline growth rates, and ranged between 0.838–0.902. Median quasi-extinction times under recurring epizootics also overlapped for most scenarios with those of baseline conditions, and ranged between 18–29 years, with both metrics decreasing as a function of f and m. Overall, baseline (enzootic) conditions had a greater impact on l than epizootic conditions, and demographic vital rates were proportionately more influential on l than disease- or outbreak-associated parameters. Lower-level elasticities revealed that, among disease- and outbreak-associated parameters, increases in m, force of infection (φ), and f negatively influenced l. The impact of disease on host population dynamics depended primarily on how often a population underwent an epizootic state, rather than how long the epizootic persisted within the exposed population. The modeling framework presented in this paper could be widely applied to a range of wildlife disease systems in which hosts suffer from persistent recurring diseases.

Upper respiratory tract disease (URTD) caused by Mycoplasma agassizii has been hypothesized to contribute to the decline of some wild populations of gopher tortoises (Gopherus polyphemus). However, the force of infection (FOI) and the effect of URTD on survival in free-ranging tortoise populations remain unknown. Using four years (2003-2006) of mark-recapture and epidemiological data collected from 10 populations of gopher tortoises in central Florida, USA, we estimated the FOI (probability per year of a susceptible tortoise becoming infected) and the effect of URTD (i.e., seropositivity to M. agassizii) on apparent survival rates. Sites with high (or = 25%) seroprevalence had substantially higher FOI (0.22 +/- 0.03; mean +/- SE) than low (25%) seroprevalence sites (0.04 +/- 0.01). Our results provide the first quantitative evidence that the rate of transmission of M. agassizii is directly related to the seroprevalence of the population. Seropositive tortoises had higher apparent survival (0.99 +/- 0.0001) than seronegatives (0.88 +/- 0.03), possibly because seropositive tortoises represent individuals that survived the initial infection, developed chronic disease, and experienced lower mortality during the four-year span of our study. However, two lines of evidence suggested possible effects of mycoplasmal URTD on tortoise survival. First, one plausible model suggested that susceptible (seronegative) tortoises in high seroprevalence sites had lower apparent survival rates than did susceptible tortoises in low seroprevalence sites, indicating a possible acute effect of infection. Second, the number of dead tortoise remains detected during annual site surveys increased significantly with increasing site seroprevalence, from approximately 1 to approximately 5 shell remains per 100 individuals. If (as our results suggest) URTD in fact reduces adult survival, it could adversely influence the population dynamics and persistence of this late- maturing, long-lived species.

We introduce a method for statistically identifying the optimal locations of deep tubewells (dtws) to be installed in Matlab, Bangladesh. Dtw installations serve to mitigate exposure to naturally occurring arsenic found at groundwater depths less than 200 meters, a serious environmental health threat for the population of Bangladesh. We introduce an objective function, which incorporates both arsenic level and nearest town population size, to identify optimal locations for dtw placement. Assuming complete knowledge of the arsenic surface, we then demonstrate how minimizing the objective function over a domain favors dtws placed in areas with high arsenic values and close to largely populated regions. Given only a partial realization of the arsenic surface over a domain, we use a Bayesian spatial statistical model to predict the full arsenic surface and estimate the optimal dtw locations. The uncertainty associated with these estimated locations is correctly characterized as well. The new method is applied to a dataset from a village in Matlab and the estimated optimal locations are analyzed along with their respective 95% credible regions.

Understanding why certain species can successfully colonize new areas while others do not is a central question in ecology. The nine-banded armadillo (Dasypus novemcinctus) is a conspicuous example of a successful invader, having colonized much of the southern United States in the last 200 years. We used 15 years (1992-2006) of capture-mark-recapture data from a population of armadillos in northern Florida in order to estimate, and examine relationships among, various demographic parameters that may have contributed to this ongoing range expansion. Modeling across a range of values for γ, the probability of juveniles surviving in the population until first capture, we found that population growth rates varied from 0.80 for γ = 0.1, to 1.03 for γ = 1.0. Growth rates approached 1.0 only when γ ≥ 0.80, a situation that might not occur commonly because of the high rate of disappearance of juveniles. Net reproductive rate increased linearly with γ, but life expectancy (estimated at 3 years) was independent of γ. We also found that growth rates were lower during a 3-year period of hardwood removal that removed preferred habitat than in the years preceding or following. Life-table response experiment (LTRE) analysis indicated the decrease in growth rate during logging was primarily due to changes in survival rates of adults. Likewise, elasticity analyses of both deterministic and stochastic population growth rates revealed that survival parameters were more influential on population growth than were those related to reproduction. Collectively, our results are consistent with recent theories regarding biological invasions which posit that populations no longer at the leading edge of range expansion do not exhibit strong positive growth rates, and that high reproductive output is less critical in predicting the likelihood of successful invasion than are life-history strategies that emphasize allocation of resources to future, as opposed to current, reproduction.

The nine-banded armadillo ( Dasypus novemcinctus ) is the only known nonhuman reservoir of Mycobacterium leprae , the causative agent of Hansen's disease or leprosy. We conducted a 6-yr study on a wild population of armadillos in western Mississippi that was exposed to M. leprae to evaluate the importance of demographic and spatial risk factors on individual antibody status. We found that spatially derived covariates were not predictive of antibody status. Furthermore, analyses revealed no evidence of clustering by antibody-positive individuals. Lactating females and adult males had higher odds of being antibody positive than did nonlactating females. No juveniles or yearlings were antibody positive. Results of these analyses support the hypothesis that M. leprae infection patterns are spatially homogeneous within this armadillo population. Further research related to movement patterns, contact among individuals, antibody status, and environmental factors could help address hypotheses related to the role of environmental transmission on M. leprae infection and the mechanisms underlying the differential infection patterns among demographic groups.