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Anthropogenically forced-warming and La Niña forced-precipitation deficits caused at least a sixfold risk increase for compound extreme low precipitation and high temperature in California–Nevada from October 2020 to September 2021. [ABSTRACT FROM AUTHOR]

Methamphetamine use is associated with morbidity and mortality, yet remains under-researched among older men who have sex with men (MSM). We used the 2017 National HIV Behavioral Surveillance Survey to identify the correlates of methamphetamine use among MSM ages 50 and older in San Francisco. Those who were HIV-positive (aOR = 30.18; 95%CI = 1.41-645.26), diagnosed with syphilis (aOR = 34.36; 95%CI = 3.26-361.76), used ecstasy (aOR = 18.84; 95%CI = 2.26-157.20), or poppers (aOR = 44.51; 95%CI = 5.28-374.99) had significantly greater odds of methamphetamine use. Interventions for older methamphetamine using MSM should address polysubstance use and sexual health. [ABSTRACT FROM AUTHOR]

Year-to-year extreme alterations in California (CA) precipitation, denoted here as flips, present significant challenges to resource managers, emergency management officials, and the state's economy and ecosystems generally. We evaluate regional (north, central, and south) and statewide flip behavior since 1571 CE utilizing instrumental data and paleoclimate reconstructions. Flips, defined as dry-to-wet and wet-to-dry consecutive alterations between the tailward 30th percentiles of the precipitation distribution, have occurred throughout this period without indication of systematic change through the recent time of modern anthropogenic forcing. Statewide ''grand flips'' are notably absent between 1892 and 1957; bootstrap Monte Carlo analysis indicates that this feature is consistent with random behavior. Composites for northeastern Pacific Ocean winter sea level pressure and jet-stream winds associated with flip events indicate anomalous high or low pressure during the core precipitation delivery season for dry or wet flip years, respectively, and jet-stream conditions that are also like those associated with individual dry or wet years. Equatorial Pacific sea surface temperatures play a partial role in both dry-to-wet and wet-to-dry events in central and southern CA in the longer-period reconstruction data, with response restricted primarily to southern CA in the smaller sample-size instrumental data. Knowledge of a prior year extreme, potentially representing initiation of a flip, provides no enhancement of prediction quality for the second year beyond that achievable from skillful seasonal prediction of equatorial Pacific sea surface temperatures. Overall, results indicate that the first-order nature of flip behavior from the later 1500s reflects the quasi-white noise nature of precipitation variability in CA, influenced secondarily by equatorial Pacific sea surface conditions, particularly in southern CA. [ABSTRACT FROM AUTHOR]

In the United States, hepatitis C virus (HCV) transmission is rising among people who inject drugs (PWID). Many regions have insufficient prevention intervention coverage. Using modeling, we investigated the impact of scaling up prevention and treatment interventions on HCV transmission among PWID in Perry County, Kentucky, and San Francisco, California, where HCV seroprevalence among PWID is >50%. A greater proportion of PWID access medication-assisted treatment (MAT) or syringe service programs (SSP) in urban San Francisco (established community) than in rural Perry County (young, expanding community). We modeled the proportion of HCV-infected PWID needing HCV treatment annually to reduce HCV incidence by 90% by 2030, with and without MAT scale-up (50% coverage, both settings) and SSP scale-up (Perry County only) from 2017. With current MAT and SSP coverage during 2017–2030, HCV incidence would increase in Perry County (from 21.3 to 22.6 per 100 person-years) and decrease in San Francisco (from 12.9 to 11.9 per 100 person-years). With concurrent MAT and SSP scale-up, 5% per year of HCV-infected PWID would need HCV treatment in Perry County to achieve incidence targets—13% per year without MAT and SSP scale-up. In San Francisco, a similar proportion would need HCV treatment (10% per year) irrespective of MAT scale-up. Reaching the same impact by 2025 would require increases in treatment rates of 45%–82%. Achievable provision of HCV treatment, alongside MAT and SSP scale-up (Perry County) and MAT scale-up (San Francisco), could reduce HCV incidence. [ABSTRACT FROM AUTHOR]

Using data from the National HIV Behavioral Surveillance of men who have sex with men (MSM), we estimated the prevalence of sexual behaviors among HIV-negative San Francisco MSM between 2004 and 2017. We estimate a recent increase in the 1-year prevalence of pre-exposure prophylaxis (PrEP) use, from 9.8% in 2014 to 44.9% in 2017. Over that same period, we estimate a decrease in the prevalence of consistent condom use, from 18.5 to 9.4%, and an increase in the percent of individuals with multiple condomless anal intercourse partners. We conclude that while risks for HIV infection may be decreasing among San Francisco MSM due, in part, to increases in PrEP use, the population faces increased risks for other sexually transmitted infections (STIs). Because PrEP alone does not protect against other STIs, we strongly recommend that PrEP users use condoms when possible, routinely screen for STIs, and disclose infections with sexual partners. [ABSTRACT FROM AUTHOR]

Current population size estimates of communities at risk for HIV are needed to adequately plan interventions and care. We update the estimated number of men who have sex with men (MSM) living in San Francisco. Multiple data sources and approaches, including population growth, registered HIV cases, wisdom of the crowd, and a published estimate on the proportion of adults who are MSM were used for estimation. The several estimates were synthesized into a final figure with acceptable bounds using a Bayesian method. We project 69,974 (acceptable bounds 65,523–74,323) MSM are living in San Francisco as of the beginning of 2017. The population of MSM in San Francisco has increased by 19.4% since 2014. [ABSTRACT FROM AUTHOR]

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Cities worldwide are striving to get to zero HIV stigma as a condition to get to zero new infections. We tracked an indicator of perceived HIV stigma across surveys of men who have sex with men (MSM) in San Francisco from 2011 to 2017. Little improvement in perceived HIV stigma was observed, from 22.3% (95% CI 18.7–26.3) of MSM agreeing with the statement "Most people would discriminate against someone with HIV" in 2011 to 21.0% (95% CI 17.5–24.9) in 2017 (χ2 test for trend 0.252, p = 0.616). Success in ending the epidemic may flag without addressing the causes of HIV stigma. [ABSTRACT FROM AUTHOR]

The recent dryness in California was unprecedented in the instrumental record. This article employs spatially explicit precipitation reconstructions for California in combination with instrumental data to provide perspective on this event since 1571. The period 2012-15 stands out as particularly extreme in the southern Central Valley and south coast regions. which likely experienced unprecedented precipitation deficits over this time, apart from considerations of increasing temperatures and drought metrics that combine temperature and moisture information. Some areas lost more than two years' average moisture delivery during these four years, and full recovery to long-term average moisture delivery could typically take up to several decades in the hardest-hit areas. These results highlight the value of the additional centuries of information provided by the paleo record, which indicates the shorter instrumental record may underestimate the statewide recovery time by over 30%. The extreme El Niño that occurred in 2015/16 ameliorated recovery in much of the northern half of the state, and since 1571 very-strong-to-extreme El Niños during the first year after a 2012-15-type event reduce statewide recovery times by approximately half. The southern part of California did not experience the high precipitation anticipated, and the multicentury analysis suggests the north-wet-south-dry pattern for such an El Niño was a low-likelihood anomaly. Recent wetness in California motivated evaluation of recovery times when the first two years are relatively wet, suggesting the state is benefiting from a one-in-five (or lower) likelihood situation: the likelihood of full recovery within two years is ~1% in the instrumental data and even lower in the reconstruction data. [ABSTRACT FROM AUTHOR]

An analysis of the October 2013-September 2014 precipitation in the western United States and in particular over the California-Nevada region suggests this anomalously dry season, while extreme, is not unprecedented in comparison with the approximately 120-yr-long instrumental record of water year (WY; October-September) totals and in comparison with a 407-yr WY precipitation reconstruction dating back to 1571. Over this longer period, nine other years are known or estimated to have been nearly as dry or drier than WY 2014. The 3-yr deficit for WYs 2012-14, which in California exceeded the annual mean precipitation, is more extreme but also not unprecedented, occurring three other times over the past approximate 440 years in the reconstruction. WY precipitation has also been deficient on average for the past 14 years, and such a run of predominantly dry WYs is also a rare occurrence in the authors' merged reconstructed plus instrumental period record. [ABSTRACT FROM AUTHOR]

White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in “central California” at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a limited number of sites and that account for all life history stages across the species' range of habitats. [ABSTRACT FROM AUTHOR]

The USA300 clone of methicillin-resistant Staphylococcus aureus causes concurrent epidemics of skin and soft tissue infections (SSTIs) and bloodstream infections (BSIs). Because USA300 SSTIs serve as a source for BSIs, strategies to control the USA300 SSTI epidemic may lessen the severity of the USA300 BSI epidemic.Background. Since its emergence in 2000, epidemic spread of the methicillin-resistant Staphylococcus aureus (MRSA) clone USA300 has led to a high burden of skin and soft tissue infections (SSTIs) in the United States, yet its impact on MRSA bloodstream infections (BSIs) is poorly characterized.Methods. To assess clonality of the MRSA isolates causing SSTI and BSI during the epidemic period, a stratified, random sample of 1350 unique infection isolates (from a total of 7252) recovered at the Community Health Network of San Francisco from 2000 to 2008 were selected for genotyping. Risk factors and outcomes for 549 BSI cases caused by the USA300 epidemic clone and non-USA300 MRSA clones were assessed by retrospective review of patient medical records.Results. From 2000 to 2008, secular trends of USA300 SSTI and USA300 BSI were strongly correlated (Pearson r = 0.953). USA300 accounted for 55% (304/549) of BSIs as it was the predominant MRSA clone that caused community-associated (115/160), healthcare-associated community-onset (125/207), and hospital-onset (64/182) BSIs. Length of hospitalization after BSI diagnosis and mortality rates for USA300 and non-USA300 were similar. Two independent risk factors for USA300 BSI were identified: concurrent SSTI (adjusted relative risk, 1.4 [95% confidence interval {CI}, 1.2–1.6]) and anti-MRSA antimicrobial use in the preceding 30 days (0.7 [95% CI, .6–.8]). Isolates from concurrent SSTI were indistinguishable genotypically from the USA300 isolates that caused BSI.Conclusions. USA300 SSTIs serve as a source for BSI. Strategies to control the USA300 SSTI epidemic may lessen the severity of the concurrent USA300 BSI epidemic. [ABSTRACT FROM AUTHOR]

Background. Methicillin-resistant Staphylococcus aureus (MRSA) infections have become a major public health problem in both the community and hospitals. Few studies have characterized the incidence and clonal composition of disease-causing strains in an entire population. Our objective was to perform a population-based survey of the clinical and molecular epidemiology of MRSA disease in San Francisco, California. Methods. We prospectively collected 3985 MRSA isolates and associated clinical and demographic information over a 12-month period (2004-2005) at 9 San Francisco-area medical centers. A random sample of 801 isolates was selected for molecular analysis. Results. The annual incidence of community-onset MRSA disease among San Francisco residents was 316 cases per 100,000 population, compared with 31 cases per 100,000 population for hospital-onset disease. Persons who were aged 35-44 years, were men, and were black had the highest incidence of community-onset disease. The USA300 MRSA clone accounted for 234 cases of community-onset disease and 15 cases of hospital-onset disease per 100,000 population, constituting an estimated 78.5% and 43.4% of all cases of MRSA disease, respectively. Patients with community-onset USA300 MRSA versus non-USA300 MRSA disease were more likely to be male, be of younger age, and have skin and soft-tissue infections. USA300 strains were generally more susceptible to multiple antibiotics, although decreased susceptibility to tetracycline was observed in both community-onset (Pp.008) and hospital-onset (Pp.03) USA300 compared to non-USA300 strains. Conclusions. The annual incidence of community-onset MRSA disease in San Francisco is substantial, surpassing that of hospital-onset disease. USA300 is the predominant clone in both the community and hospitals. The dissemination of USA300 from the community into the hospital setting has blurred its distinction as a community-associated pathogen. [ABSTRACT FROM AUTHOR]

Extreme events shape population and community trajectories. We report episodic mortality across common species of thousands of long-lived perennials individually tagged and monitored for 20 years in the Colorado Desert of California following severe regional drought. Demographic records from 1984 to 2004 show 15 years of virtual stasis in populations of adult shrubs and cacti, punctuated by a 55–100% die-off of six of the seven most common perennial species. In this episode, adults that experienced reduced growth in a lesser drought during 1984–1989 failed to survive the drought of 2002. The significance of this event is potentially profound because population dynamics of long-lived plants can be far more strongly affected by deaths of adults, which in deserts potentially live for centuries, than by seedling births or deaths. Differential mortality and rates of recovery during and after extreme climatic events quite likely determine the species composition of plant and associated animal communities for at least decades. The die-off recorded in this closely monitored community provides a unique window into the mechanics of this process of species decline and replacement. [ABSTRACT FROM AUTHOR]

To characterize methicillin-resistant Staphylococcus aureus (MRSA) strains circulating in the community, we identified predictors of isolating community MRSA and genotyped a sample of MRSA collected from a community-based, high-risk population. Computerized databases of the Community Health Network of San Francisco and the Clinical Microbiology Laboratory were searched electronically for the years 1992-1 999 to identify community-onset infections caused by MRSA. Sequential analyses were performed to identify predictors of MRSA strains. The majority (58%) of infections were caused by strains traceable to the hospital or to long- term care facilities. Injection drug use was associated with infections that were not associated with health care settings. Genotypes for 20 of 35 MRSA isolates recovered from injection drug users did not match any of >600 genotypes of clinical isolates. In a nonoutbreak setting, the hospital was the main source of community MRSA; however, the presence of genetically distinct and diverse MRSA strains indicates MRSA strains now also originate from the community. [ABSTRACT FROM AUTHOR]

The study objective was to determine the prevalence and risk factors for nasal colonization with Staphylococcus aureus and methicillin resistance among the urban poor and to compare antibiotic resistance and genetic similarity to concurrently collected clinical isolates of methicillin-resistant S. aureus (MRSA). A population-based community sample of 833 homeless and marginally housed adults were cultured and compared with 363 clinical isolates of MRSA; 22.8% of the urban poor were colonized with S. aureus. Of S. aureus isolates, 12.0% were methicillin resistant. Overall prevalence of MRSA was 2.8%. Significant multivariate risk factors for MRSA were injection drug use (odds ratio [OR], 9.7), prior endocarditis (OR, 4.1), and prior hospitalization within 1 year (OR, 2.4). Resistance to antimicrobials other than β -lactams was uncommon. Only 2 individuals (0.24%) with MRSA had no known risk factors. A total of 22 of 23 community MRSA genotypically matched clinical MRSA isolates, with 15 of 23 isolates identical to MRSA clones endemic among hospitalized patients. [ABSTRACT FROM AUTHOR]

Background: Clinicians need to decide whether to begin empiric therapy for patients who are suspected of having tuberculosis (TB) but have negative sputum smear results. Culture results may take weeks, and delaying treatment may allow further transmission of disease. Study objective: To identify the clinical, demographic, and radiographic characteristics that identify smear-negative patients who have TB, and to create a TB prediction rule. Design: Retrospective chart review. Setting: University-affiliated public hospital in San Francisco, CA, between 1993 and 1998. Patients: Forty-seven patients with TB and 141 control patients who were hospitalized with a suspicion of puhnonary TB; all had negative sputum smear results. Measurements and results: Demographic, clinical, and radiographic variables were determined by chart review. In multivariate analysis, a positive tuberculin skin test result (odds ratio [OR], 4.8; 95% confidence interval [CI], 2.0 to 11.9) was independently associated with an increased risk of a positive TB culture finding. A radiographic pattern not typical of pulmonary tuberculosis (OR, 0.3; 95% CI, 0.1 to 0.7) and expectoration with cough (OR, 0.3; 95% CI, 0.1 to 0.6) were predictive of a decreased risk. An interaction between HIV seropositivity and mediastinal lymphadenopathy on the chest radiograph was also associated with a positive TB culture result (OR, 7.2; 95% CI, 1.4 to 36.0). The TB prediction score (TPS) was created with widely ranging likelihood ratios that could affect the posterior probability of TB by 30-fold. Conclusion: The TPS put into context with the overall prevalence of TB in a given area may help clinicians decide if a patient with negative sputum smear results should start empiric antituberculous therapy or wait for culture results. These results need prospective validation. [ABSTRACT FROM AUTHOR]

Satellite estimation of oceanic chlorophyll-a content has enabled characterization of global phytoplankton stocks, but the quality of retrieval for many ocean color products (including chlorophyll-a) degrades with increasing phytoplankton biomass in eutrophic waters. Quality control of ocean color products is achieved primarily through the application of masks based on standard thresholds designed to identify suspect or low-quality retrievals. This study compares the masked and unmasked fractions of ocean color datasets from two Eastern Boundary Current upwelling ecosystems (the California and Benguela Current Systems) using satellite proxies for phytoplankton biomass that are applicable to satellite imagery without correction for atmospheric aerosols. Evaluation of the differences between the masked and unmasked fractions indicates that high biomass observations are preferentially masked in National Aeronautics and Space Administration (NASA) ocean color datasets as a result of decreased retrieval quality for waters with high concentrations of phytoplankton. This study tests whether dataset modification persists into the default composite data tier commonly disseminated to science end users. Further, this study suggests that statistics describing a dataset's masked fraction can be helpful in assessing the quality of a composite dataset and in determining the extent to which retrieval quality is linked to biological processes in a given study region. [ABSTRACT FROM AUTHOR]

Background: As resources are deployed to address the opioid overdose epidemic in the USA, it is essential that we understand the correlates of more frequent opioid injections-which has been associated not only with HIV and HCV transmission, but also with overdose risk-to inform the development and targeting of effective intervention strategies like overdose prevention and naloxone distribution programs. However, no studies have explored how characteristics of opioid use partnerships may be associated within injection frequency with opioid partnerships.Methods: Using baseline data from a trial of a behavioural intervention to reduce overdose among opioid users in San Francisco, CA, we calculated assortativity among opioid use partnerships by race, gender, participant-reported HIV- and HCV-status, and opioids used using Newman's assortativity coefficient (NC). Multivariable generalized estimating equations linear regression was used to examine associations between individual- and partnership-level characteristics and injection frequency within opioid use partnerships.Results: Opioid use partnerships (n=134) reported by study participants (n=55) were assortative by race (NC=0.42, 95%CI=0.33-0.50) and participant-reported HCV-status (NC=0.42, 95%CI=0.31-0.52). In multivariable analyses, there were more monthly injections among sexual/romantic partnerships (β=114.4, 95%CI=60.2-168.7, p<0.001), racially concordant partnerships reported by white study participants (β=71.4, 95%CI=0.3-142.5, p=0.049), racially discordant partnerships reported by African American study participants (β=105.7, 95%CI=1.0-210.5, p=0.048), and partnerships in which either member had witnessed the other experience an overdose (β=81.8, 95%CI=38.9-124.6, p<0.001).Conclusion: Social segregation by race and HCV-status should potentially be considered in efforts to reach networks of opioid users. Due to higher injection frequency and greater likelihood of witnessing their partners experience an overdose, individuals in sexual/romantic opioid use partnerships, white individuals in racially homogenous partnerships, and African American individuals in heterogeneous partnerships may warrant focused attention as part of peer- and network-based overdose prevention efforts, as well as broader HIV/HCV prevention strategies. Developing and targeting overdose prevention education programs that provide information on risk factors and ways to identify overdose, as well as effective responses, including naloxone use and rescue breathing, for more frequently injecting networks may help reduce opioid morbidity and mortality in these most at risk groups. [ABSTRACT FROM AUTHOR]

Extending from central California to Alaska, bull kelp (Nereocystis luetkeana) forms seasonal kelp forests that are iconic coastal ecosystems in much of the eastern Pacific. Historical and ongoing field surveys and aerial imagery are used to provide biological data on kelp canopy cover and health, but satellite remote sensing provides the opportunity to generate consistent, long-term datasets over a large spatial scale. Robust satellite-based timeseries measurements of giant kelp (Macrocystis pyrifera) are available for much of the California coastline (e.g., Santa Barbara to Santa Cruz), but there have been no equivalent publications for bull kelp. Recent loss of bull kelp in northern California emphasized the need for more expansive long-term monitoring of canopy trends. We tested various kelp classification approaches using Multiple Endmember Spectral Mixture Analysis (MESMA) applied to Landsat imagery, which allowed sufficient temporal and spatial data collection during bull kelp's narrow seasonal maximum, and compare with the California Department of Fish and Wildlife (CDFW) aerial survey canopy area product. We addressed five main topics that have relevance to enabling Landsat in long-term monitoring of bull kelp canopy coverage in northern California: (1) the effect of MESMA configurations applied to Landsat imagery, including software dependencies and endmember configurations, (2) comparison of Landsat to traditional surveys, (3) differences across Landsat sensors, (4) tidal influence on canopy area, and (5) trends in the decadal timeseries. We found that there was no statistical difference (p = 0.53) between MESMA platforms (IDL-based and a Python-scripted method; RMSE 1.5 km2 or 17.6% when normalized by the range in CDFW), and that a 7-endmember MESMA model provided the lowest RMSE (1.4 km2 or 16.9%). Furthermore, while tidal phases can submerge or emerge kelp canopy and thus potentially affect kelp detection, we found a weak and statistically insignificant correlation between tides and performance of our remote estimate of kelp canopy area. Canopy estimations from Landsat-8 images yielded a higher NRMSE than Landsat-4 and -5 images, but the lack of matchup limits comparison. Imagery from early fall yielded the largest coverage estimates. Overall, our results show that Landsat enables broad remote measurement of bull kelp canopy coverage to supplement existing survey methods and increase continuity of timeseries for monitoring long-term trends. • Landsat methods produce bull kelp coverage comparable to aerial surveys. • Low kelp coverage increases uncertainty in both satellite and aerial survey methods. • Landsat resample rate allows measurements during peak coverage in early fall. • Satellite methods are robust to tidal cycle. • Methods support time series analysis of recent kelp declines. [ABSTRACT FROM AUTHOR]

Background: Globally, people who inject drugs (PWID) are disproportionately at risk for HIV and HCV due to risky injection drug use behaviors, such as sharing used needles and injection kits. In response, San Francisco, one of several cities with a sizable PWID population that had quickly committed to stopping the spread of HIV/HCV, have expanded needle access, including in pharmacies and hospitals, in order to ensure that PWID inject with clean needles. However, there was no current research on whether each source of needles is equally associated with always using new sterile needles in San Francisco. Furthermore, no research in San Francisco had examined behavioral trends in needle-sharing practices, the relationship between PWID and their injection partners, and knowledge of their injection partners' HIV or HCV status.Methods: Therefore, we analyzed data from three cycles of the National HIV Behavioral Surveillance studies from 2005 to 2012 in San Francisco among PWID.Results: The results from our analysis suggest that overall risky drug injection practices, such as injecting with used needles, sharing used cookers or water, and dividing drugs with a used syringe, among PWID in San Francisco has decreased from 2005 to 2012. An increasing proportion of PWID are injecting with their friend/acquaintance than with their sex partner. Also, a declining portion of PWID report knowing their last injection partner's HIV-positive or HCV-positive status. In terms of sources of needles, less PWID are getting their needles from friends and drug dealers while a greater proportion are using pharmacies and needle exchanges. However, pharmacies as a source of needles are negatively associated with always using new sterile needles.Conclusion: From 2005 to 2012, overall high-risk injection behavior among PWID in SF has decreased including PWID that are injecting with others. However, our results suggest caution over the expansion of pharmacies as a source of needles in San Francisco and in similar cities due to their negative association with always using a new sterile needle. Since more PWID are injecting with their friend/acquaintance, interventions at needle access programs at pharmacies, hospitals, and needle exchanges should stress the potential to transmit HIV and HCV even in one-on-one sharing situations. Furthermore, since a decreasing percentage of PWID know about their injection partner's HIV/HCV status, such interventions should also highlight the importance of having a conversation about HIV and HCV status with one's injecting partner. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To test the hypothesis that the profile of sudden infant death syndrome (SIDS) changed after the Back-to-Sleep (BTS) campaign initiation, document prevalence and patterns of multiple risks, and determine the age profile of risk factors. METHODS: The San Diego SIDS/Sudden Unexplained Death in Childhood Research Project recorded risk factors for 568 SIDS deaths from 1991 to 2008 based upon standardized death scene investigations and autopsies. Risks were divided into intrinsic (eg, male gender) and extrinsic (eg, prone sleep). RESULTS: Between 1991-1993 and 1996-2008, the percentage of SIDS infants found prone decreased from 84.0% to 48.5% (P < .001), bed- sharing increased from 19.2% to 37.9% (P < .001), especially among infants <2 months (29.0% vs 63.8%), prematurity rate increased from 20.0% to 29.0% (P = .05), whereas symptoms of upper respiratory tract infection decreased from 46.6% to 24.8% (P < .001). Ninety-nine percent of SIDS infants had at least 1 risk factor, 57% had at least 2 extrinsic and 1 intrinsic risk factor, and only 5% had no extrinsic risk. The average number of risks per SIDS infant did not change after initiation of the BTS campaign. CONCLUSIONS: SIDS infants in the BTS era show more variation in risk factors. There was a consistently high prevalence of both intrinsic and especially extrinsic risks both before and during the Back-to-Sleep era. Risk reduction campaigns emphasizing the importance of avoiding multiple and simultaneous SIDS risks are essential to prevent SIDS, including among infants who may already be vulnerable. [ABSTRACT FROM AUTHOR]

White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central California" at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a limited number of sites and that account for all life history stages across the species' range of habitats.

Objective: To examine whether infants reported for maltreatment face a heightened risk of sudden infant death syndrome (SIDS) and other leading causes of sudden unexpected infant death (SUID)., Study Design: Linked birth and infant death records for all children born in California between 1999 and 2006 were matched to administrative child protection data. Infants were prospectively followed from birth through death or 1 year of age. A report of maltreatment was modeled as a time-varying covariate; risk factors at birth were included as baseline covariates. Multivariable competing risk survival models were used to estimate the adjusted relative hazard of postneonatal SIDS and other SUID., Results: A previous maltreatment report emerged as a significant predictor of SIDS and other SUID. After adjusting for baseline risk factors, the rate of SIDS was more than 3 times as great among infants reported for possible maltreatment (hazard ratio: 3.22; 95% CI: 2.66, 3.89)., Conclusion: Infants reported to child protective services have a heightened risk of SIDS and other SUID. Targeted services and improved communication between child protective services and the pediatric health care community may enhance infant well-being and reduce risk of death., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Current classification schemes for sudden unexpected infant death (SUID) may not be optimal for capturing scene events that potentially predispose to asphyxia. (1) To compare causes of death in a group of SUID cases assigned by multiple reviewers using our recently published classification scheme for SUID that is based on asphyxial risk at the death scene, and (2) To compare these newly assigned causes of death to that originally assigned by the medical examiners of record who performed the autopsies. Five reviewers independently assigned causes of death for 117 cases of SUID, including 83 originally diagnosed as sudden infant death syndrome (SIDS), accessioned into the San Diego SIDS/SUDC Research Project from the San Diego County Medical Examiner's Office. The diagnostic categories are: A: SIDS; B: Unexplained-Potentially Asphyxia; C: Unexplained-Other Potential Causes of Death; D: Unclassified-Other; E: Unclassified; and F: Known Cause of Death. The reviewers collectively opined that conditions at the death scene contributed to or caused death in 32-50% of all of the 117 cases as well as in 40-59% of the 83 originally diagnosed SIDS cases. Another cause of death was considered plausible in 2-12% of the SIDS cases. Application of this new classification system resulted in 55-69% decrease in SIDS diagnoses. Asphyxia as a potential contributor to, or as the specific cause of death, appears to exist in a large percentage of cases designated as SIDS using other classification schemes. When certifiers use a classification system that focuses upon potential asphyxia in determining the cause of death the incidence of SIDS dramatically declines.

Background: Despite an effective vaccine, 60,000 new HBV infections were reported in the US in 2004; 95% in adults. We evaluate HBV sero-prevalence, risk behaviors and self-reported vaccination among Latino immigrant, Asian immigrant and US born low income men in five northern California counties., Methods: Population based, cross sectional survey of HBV sero-prevalence and risk behaviors in men aged 18 to 35 years., Results: Among 1,512 men screened, Asian immigrants were most likely to have had prior HBV infection (15.1%) and chronic infection (3.8%) compared to US born (prior 5.1%, chronic 0.6%) and Latino immigrant men (prior 2.0%, chronic 0.3%.) Reported HBV vaccination was lowest for Latino immigrants (12%) compared to Asian immigrants and US born men (35% in both.) Latino immigrants reported less educational attainment, medical insurance coverage and access to a physician in the last six months., Discussion: Healthcare providers should routinely screen Asian immigrants for HBV regardless of their self reported vaccination status. Latino immigrants may comprise an important group of under-vaccinated, at risk persons in California. HBV testing and vaccination of immigrants soon after US arrival should be encouraged.

Literature addressing the anatomic development of the dura and calvarium during childhood is limited. Nevertheless, histological features of a subdural neomembrane (NM), including its thickness and vascularity, developing in response to an acute subdural hematoma (SDH) have been compared to the dura of adults to estimate when an injury occurred. Therefore, we measured the morphometric growth of the calvarium and dura and the vascular density within the dura during infancy. The mean thicknesses of the calvarium and dura as a function of occipitofrontal circumference (OFC), as well as the mean number of vessels per 25 × field, were determined from the right parasagittal midparietal bone lateral to the sagittal suture of 128 infants without a history of head trauma. Our results showed that as OFC increased, the mean thicknesses of the calvarium and dura increased while the vascular density within the dura decreased. Our morphometric data may assist in the interpretation of subdural NM occurring during infancy. We recommend future investigations to confirm and extend our present data, especially by evaluating cases during later infancy and beyond as well as by sampling other anatomic sites from the calvarium. We also recommend morphometric evaluation of subdural NM associated with SDH in infancy and childhood.

Dysfunction of medullary serotonin (5-HT)-mediated respiratory and autonomic function is postulated to underlie the pathogenesis of the majority of sudden infant death syndrome (SIDS) cases. Several studies have reported an increased frequency of the LL genotype and L allele of the 5-HT transporter (5-HTT) gene promoter polymorphism (5-HTTLPR), which is associated with increased transcriptional activity and 5-HT transport in vitro, in SIDS cases compared with controls. These findings raise the possibility that this polymorphism contributes to or exacerbates existing medullary 5-HT dysfunction in SIDS. In this study, we tested the hypothesis that the frequency of LL genotype and L allele are higher in 179 SIDS cases compared with 139 controls of multiple ethnicities in the San Diego SIDS Dataset. We observed no significant association of genotype or allele with SIDS cases either in the total cohort or on stratification for ethnicity. These observations do not support previous findings that the L allele and/or LL genotype of the 5-HTTLPR are associated with SIDS.

A fraction of SIDS cases have death delayed by successful CPR, yet they have not been compared to SIDS cases which were found dead or not successfully resuscitated. Our aims were to: (1) determine the percent of SIDS cases in the San Diego SIDS Research Project database for whom death was delayed by CPR and subsequent life support; (2) compare demographics, circumstances of death and autopsy findings of delayed death SIDS cases (delayed SIDS) with those whose deaths were not delayed (non-delayed SIDS); (3) examine the evolution of pathologic changes in delayed SIDS as a function of survival interval. A retrospective 15-year population-based study of 454 infant deaths attributed to SIDS revealed 29 delayed SIDS cases (Group I) and 425 non-delayed SIDS cases (Group II). Group I cases were significantly older than Group II cases (mean age 132 days vs. 102 days and p<0.0001). Eighty-nine percent of the Group I cases were discovered between 08.00 and 19.59 h; none were found between 00.00 and 07.59 h, compared to 38% of the Group II cases. Group I infants were found significantly more often away from home (at daycare, or at the home of a relative, friend, or baby sitter) than Group II infants (45% vs. 25%, p<0.05). There were no differences between groups with regard to gender, gestational age, type of delivery, bed sharing, URI within 48 h of death, ALTEs, a history of referral to child protective services, body position when placed or found, or face position when found. Pathologic changes were semiquantitatively evaluated; findings were characteristic of anoxic-ischemic injury that generally became more severe with increasing survival intervals. Anoxic-ischemic brain injury was the immediate cause of death in all delayed SIDS cases. Aspiration of gastric contents was identified in Group I cases surviving less than 48 h and was the likely etiology of acute bronchopneumonia occurring in 83% of the Group I cases. We did not identify factors that would reliably predict which SIDS cases might be discovered soon enough to allow earlier and more effective CPR and survival without permanent brain injury.

Intrathoracic petechiae (IP), the most common gross finding in sudden infant death syndrome (SIDS) cases at autopsy, suggest upper airway obstruction (UAO) occurs during the terminal event. If true, IP would be expected more frequently among SIDS cases found face down compared to other face positions. We compare the rates of IP in SIDS cases found face down versus other face positions. A retrospective 15-year review of IP among all cases of SIDS occurring from 1991 through 2005 accessioned by the San Diego County Medical Examiner's Office was conducted. The presence or absence of IP was based on both gross and microscopic observations of the thoracic organs. The severity of thymic petechiae was scored semiquantitatively from microscopic observations. There were 489 SIDS cases during the study period. Sixteen of these were excluded because their deaths had been delayed by initially successful cardiopulmonary resuscitation. Among the remaining 473 SIDS cases, face position when found was specifically described for 332 (70%). Of 122 cases found face down, 112 (92%) had IP, compared to 85% (179) of 210 infants found with the face up or to the side (P = 0.06). The groups were not different with respect to age or gender, but the racial distribution was significantly different (P = 0.004). African-American infants comprised 28% of the found face down group compared to only 12% of the face up or side group. Our data do not support a role for external UAO caused by face positioning directly into the sleep surface in SIDS, but are consistent with internal UAO associated with apnea or gasping before dying of SIDS.

Whether levels of fetal hemoglobin (HbF), a possible marker of antecedent hypoxemia, are increased in sudden infant death syndrome (SIDS) compared to controls is unresolved. Our aims are to: (1) Compare percent fetal hemoglobin (%HbF) levels in SIDS and control cases, and (2) compare our findings with those reported in previous studies. Using Triton-acid-urea gel electrophoresis and quantitative densitometry, %HbF was determined in whole blood specimens obtained at autopsy from SIDS and control cases accessioned into the San Diego SIDS/SUDC Research Project database. The SIDS and control cases were not different with respect to mean age, gender, gestational age, method of delivery, birth weight, or mean autopsy interval; %HbF levels in SIDS and control cases were not significantly different. Given that our results were obtained using optimal methods in well-defined SIDS and control cases, we concur with others that %HbF is not elevated in SIDS.

The potential diagnostic significance of prior family referral to Child Protective Services (CPS) in cases of sudden infant death is unknown. Therefore, the authors retrospectively searched for CPS data for the 5-year referral history on all 533 families whose infants died suddenly from Sudden Infant Death Syndrome (SIDS), other natural diseases, accidents, or inflicted injuries and underwent postmortem examination by the medical examiner during a 10-year period. No family had more than one infant death. At least 27% of the families in each group had at least one CPS referral. The data suggest that a family's referral to CPS prior to their sudden death of their infant does not increase the likelihood that it was caused by inflicted injuries, and prior referral should not preclude a diagnosis of SIDS. The authors recommend future prospective studies that include refined exposure histories and that are large enough to have sufficient statistical power to compare family CPS referrals and outcomes in groups of infants who died suddenly with a matched group of living infants.

Tumors are rare causes of sudden death in infancy and early childhood. The goals of this study were to determine the types and frequency of the tumors associated with sudden death occurring in cases between birth and age 3 years. The San Diego Sudden Infant Death Syndrome/sudden unexplained death in childhood (SUDC) Research Project database and the literature were reviewed retrospectively. Sixty-eight cases, with the most (84%) affecting the heart and brain, were identified. Tumors are a rare but significant cause of sudden death in infancy and early childhood, and their diagnosis may have significant genetic implications for planning future pregnancies. The diagnosis of these lesions can be established only after thorough postmortem examination.

The decline in the incidence of sudden infant death syndrome (SIDS) and recent recommendations regarding the differentiation of SIDS and child abuse has generated speculation that some cases of infanticide were misdiagnosed as SIDS. The aims of this study were to determine the change in incidences and proportions of postneonatal deaths from all causes, SIDS, and infanticide in California over an 18-year interval encompassing years before and after the Back to Sleep campaign. Selected postneonatal mortality data from 1981 through 1998 obtained from the California Department of Health Services were analyzed and graphically displayed. The total postneonatal mortality and incidence of SIDS deaths per 100,000 live births decreased 45% and 66%, respectively, during the study interval; the incidence of infanticide remained low. The ratio of infanticide to SIDS increased from 4.3 per 100 in 1981 to 10.2 per 100 in 1998. Infanticide deaths, as a percentage of the total number of postneonatal deaths, increased slightly from the first to the second half of the study interval but never rose above 3.2%. It is concluded that this increased percentage is due to a decrease in SIDS deaths and not to an actual increase in infanticide deaths.