A simulation model of AIDS in San Francisco: I. Model formulation and parameter estimation.

A model is formulated for the spread of the human immunodeficiency virus (HIV) and the subsequent development of acquired immunodeficiency syndrome (AIDS) in the population of homosexual men in San Francisco. The dynamic simulation model includes sexually very active and active subpopulations, migration, and a staged progression of HIV-infected persons to AIDS and death. Numerous data sources are used to estimate parameter values in the model. In a companion paper, simulations using the model and parameter estimates are found that are consistent with HIV and AIDS incidence data.     

Risk for AIDS in multiethnic neighborhoods in San Francisco,California. The population-based AMEN Study.

To examine the actual and potential spread of human immunodeficiency virus (HIV) from an acquired immunodeficiency syndrome (AIDS) epicenter to surrounding neighborhoods, we studied the prevalence of the viral infection and AIDS risk behaviors from 1988 to 1989 in a representative sample of unmarried whites, African Americans, and Hispanics living in San Francisco. We surveyed 1,770 single men and women aged 20 to 44 years (a 64% response rate) in a random household sample drawn from 3 neighborhoods of varying geographic and cultural proximity to the Castro District where the San Francisco epidemic began. Of 1,369 with blood tests, 69 (5%) had HIV antibodies; all but 5 of these reported either homosexual activity (32% HIV-positive; 95% confidence interval [CI] = 23%, 41%), injection drug use (5% HIV-positive; CI = 1%, 14%), or both (59% HIV-positive; CI 42%, 74%). Homosexual activity was more common among white men than among African-American or Hispanic men, but the proportion of those infected was similar in the 3 races. Both the prevalence of homosexually active men and the proportion infected were much lower in the 2 more outlying neighborhoods. Risk behaviors in the past year for acquiring HIV heterosexually--sex with an HIV-infected person or homosexually active man or injection drug user, unprotected sexual intercourse with more than 4 partners, and (as a proxy) having a sexually transmitted disease--were assessed in 1,573 neighborhood residents who were themselves neither homosexually active men nor injection drug users. The prevalence of reporting at least 1 of these risk behaviors was 12% overall, and race-gender estimates ranged from 5% among Hispanic women to 21% among white women. We conclude that in San Francisco, infection with HIV is rare among people who are neither homosexually active nor injection drug users, but the potential for the use spread of infection is substantial, as 12% of this group reported important risk behaviors for acquiring the virus heterosexually.     

Empirical Evidence for Synchrony in the Evolution of TB Cases and HIV+ Contacts among the San Francisco Homeless

The re-emergence of tuberculosis (TB) in the mid-1980s in many parts of the world, including the United States, is often attributed to the emergence and rapid spread of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). Although it is well established that TB transmission is particularly amplified in populations with high HIV prevalence, the epidemiology of interaction between TB and HIV is not well understood. This is partly due to the scarcity of HIV-related data, a consequence of the voluntary nature of HIV status reporting and testing, and partly due to current practices of screening high risk populations through separate surveillance programs for HIV and TB. The San Francisco Department of Public Health, TB Control Program, has been conducting active surveillance among the San Francisco high-risk populations since the early 1990s. We present extensive TB surveillance data on HIV and TB infection among the San Francisco homeless to investigate the association between the TB cases and their HIV+ contacts. We applied wavelet coherence and phase analyses to the TB surveillance data from January 1993 through December 2005, to establish and quantify statistical association and synchrony in the highly non-stationary and ostensibly non-periodic waves of TB cases and their HIV+ contacts in San Francisco. When stratified by homelessness, we found that the evolution of TB cases and their HIV+ contacts is highly coherent over time and locked in phase at a specific periodic scale among the San Francisco homeless, but no significant association was observed for the non-homeless. This study confirms the hypothesis that the dynamics of HIV and TB are significantly intertwined and that HIV is likely a key factor in the sustenance of TB transmission among the San Francisco homeless. The findings of this study underscore the importance of contact tracing in detection of HIV+ individuals that may otherwise remain undetected, and thus highlights the ever-increasing need for HIV-related data and an integrative approach to monitoring high-risk populations with respect to HIV and TB transmission.     

CEREBRAL PALSY—An Approach to the Problem

A program for the cerebral palsied child has been developed in California which has been made possible through the cooperation of the state and local departments of education, the state and local departments of health, the Children''s Hospital and Orthopedic Hospital at Los Angeles and the University of California School of Medicine in San Francisco. An attempt is being made to deal with not only the medical and educational needs of the cerebral palsied but also the social and emotional aspects.     

The Role of a Community-Based Satellite Clinic in the Perinatal Care of Non-English-Speaking Immigrants

In the provision of health care to non-English-speaking immigrants, cultural and linguistic barriers often deter both access to and use of needed services. This is especially true of the preventive health interventions such as perinatal care and family planning that contribute significantly to reproductive health.Alternative approaches to overcoming barriers to care are being taken in an urban health department clinic serving as a satellite perinatal resource to a group of low-income Chinese-speaking immigrants. The clinic, with service linkages to San Francisco General Hospital Medical Center and the Health Department of San Francisco City and County, is an example of culturally appropriate comprehensive perinatal care. Such an institution has helped recent immigrants adapt to their new environment and learn to use health services effectively.     

Introduction of the soybean to Illinois

Events leading to the planting of the first soybeans in Illinois and the subsequent distribution of the seed throughout the United States are documented. In December 1850 theAuckland left Hong Kong for San Francisco. The ship came across a Japanese junk floundering on the sea. The Japanese crew was removed from the junk and placed on board theAuckland, which continued on to San Francisco. In March 1851 Dr. Benjamin Franklin Edwards obtained soybean seeds from the Japanese and brought the seeds to Alton, Illinois. Mr. John H. Lea of Alton planted the soybeans in his garden in summer 1851. These events took place 3 yr prior to the famous introduction of soybeans from Japan into the United States by the Perry Expedition.     

Big changes to a small bay: introduced species and long-term compositional shifts to the fouling community of Morro Bay (CA)

Invasive species are cited as being a threat to communities and ecosystems worldwide, yet few studies have demonstrated invader impacts at these scales. Lack of historic data makes capturing large-scale community shifts problematic. We assessed long-term changes in invertebrate composition to the fouling community of a small estuary with relatively little boat traffic and no ballast water input (Morro Bay, CA). We also compared relative invasiveness of Morro Bay to international harbors (San Francisco Bay and Los Angeles/San Diego harbors). While the proportion of introduced species has not significantly changed from historic records, introduced species now occupy 86.00 % of the primary substrate. Other community shifts include; (1) a state shift to an invasive bryozoan (Watersipora subtorquata) dominated community, (2) a decrease in Mollusc richness and, (3) substantial shifts in abundance of certain species. Compared to larger more actively used harbors, Morro Bay has proportionally fewer introduced species (12.00 %) than San Francisco Bay (50.79 %) or Los Angeles/San Diego Harbors (26.23 %). Our study documents changes to a small relatively isolated estuary with little boat traffic and no ballast water input. We discuss the potential role of invasive species and other natural and anthropogenic factors as drivers of these community wide shifts. Specifically, we discuss how reintroduction of the Southern Sea Otter (Enhydra lutris nereis), an increase in sea stars (Pisaster spp.), climate change and interaction amongst potential drivers support the patterns of shifts in the Morro Bay community.     

OPERATIONS UPON THE AGED

From the point of view of the surgeon, as repeatedly emphasized in the surgical literature, the mortality rate for operations upon old persons is only slightly higher for elective surgical operations than for the same operations on younger persons when proper preoperative and postoperative precautions are taken. However, the mortality rate for emergency operations is much higher in old persons than in younger ones. Many surgeons believe, therefore, that disease for which operation is otherwise indicated should be treated surgically irrespective of the age of the patient per se.The authors'' experience with operations upon old persons at the San Francisco Hospital accords with these conclusions.     

Do physicians have an ethical obligation to care for patients with AIDS?

This paper responds to the question: Do physicians have an ethical obligation to care for patients with acquired immunodeficiency syndrome (AIDS)? First, the social and political milieu in which this question arises is sampled. Here physicians as well as other members of the community are found declaring an unwillingness to be exposed to people with AIDS. Next, laws, regulations, ethical codes and principles, and the history of the practice of medicine are examined, and the literature as it pertains to these areas is reviewed. The obligation to care for patients with AIDS, however, cannot be located in an orientation to morality defined in rules and codes and an appeal to legalistic fairness. By turning to the orientation to morality that emerges naturally from connection and is defined in caring, the physicians'' ethical obligation to care for patients with AIDS is found. Through an exploration of the writings of modern medical ethicists, it is clear that the purpose of the practice of medicine is healing, which can only be accomplished in relationship to the patient. It is in relationship to patients that the physician has the opportunity for self-realization. In fact, the physician is physician in relationship to patients and only to the extent that he or she acts virtuously by being morally responsible for and to those patients. Not to do so diminishes the physician''s ethical ideal, a vision of the physician as good physician, which has consequences for the physician''s capacity to care and for the practice of medicine.     

AZT toxicity and AIDS prophylaxis: Is AZT beneficial for HIV+ asymptomatic persons with 500 or more T4 cells per cubic millimeter?

Analyses of the effects of prophylactic use of zidovudine (AZT) on progression to acquired immune deficiency syndrome (AIDS) in human immunodeficiency virus seropositive (HIV+) asymptomatic persons with T4 lymphocyte (CD4+) cell counts 500 mm³ is reported for data obtained from two studies, the Australian European Group Collaborative Study, a multi-centered double-blind placebo-controlled clinical trial of the effects of AZT on progression to AIDS and other clinical endpoints, and the San Francisco Men's Health Study, an observational cohort. The analyses of the data of both studies demonstrate no benefit from AZT treatment in terms of progression to AIDS for those who are asymptomatic with CD4+ cell counts 500 mm³. The analysis of the San Francisco study, performed with Kaplan-Meier survivorship estimates, indicates a heterogeneity in the efficacy of AZT between baseline CD4+ cell count strata, 200–499 mm³ and 500–800 mm³. Within the 200–499 stratum, 47% of those receiving AZT therapy and 62% of those not receiving AZT therapy progressed to AIDS during the study period. By contrast, within the 500–800 stratum 41% of those receiving AZT therapy and 27% of those not receiving AZT therapy progressed to AIDS during the same period. Application of the Cox proportional hazards survivorship regression model for the relative risk of progression to AIDS to these same data accounts for this heterogeneity. The model includes an interaction between AZT treatment and baseline CD4+ cell counts. The hematological toxicity of AZT, demonstrated in clinical studies and laboratory investigations, indicates a biological correlate for this interaction: the toxic effects of AZT on the more intact immune system of those with CD4+ cell counts in the 500–800 mm³ range.Abbreviations ACTG AIDS Clinical Trials Group - AIDS Acquired immune deficiency syndrome - AMT 3-amino-3-deoxythymidine - ARC AIDS-related-complex - AZT 3-azido-3-deoxythymidine, zidovudine - BFU-E Erythrocyte burst-forming units - CD4+ T4 lymphocyte - CFU-GM Granulocyte macrophage colony-forming units - EAGCS European-Australian Group Collaborative Study - HIV Human immunodeficiency virus - SFMHS San Francisco Men's Health Study     

General practitioners and management of infection with HIV

General practitioners will have an increasingly important role in the management of patients with the acquired immune deficiency syndrome (AIDS) and infections with human immunodeficiency virus (HIV) as the numbers of cases increase. Altogether 280 general practitioners working in Oxfordshire were sent a postal questionnaire inquiring about their education, knowledge, current practice, and attitudes in relation to managing infections with HIV. Of the 235 (84%) general practitioners who replied, nine out of 10 were giving advice about infection with HIV to their patients. One in two were testing patients for such infection, and one in four were caring for infected patients. Nevertheless, uncertainty remained about the risks of transmission of infection with HIV and general practitioners'' knowledge of educational activities for their patients could be improved.The introduction of a facilitator to work with general practitioners in managing patients with AIDS or infection with HIV is planned, especially to help general practitioners develop the skills needed for prevention.     

First Reported Case of Cryptococcus gattii in the Southeastern USA: Implications for Travel-Associated Acquisition of an Emerging Pathogen

In 2007, the first confirmed case of Cryptococcus gattii was reported in the state of North Carolina, USA. An otherwise healthy HIV negative male patient presented with a large upper thigh cryptococcoma in February, which was surgically removed and the patient was started on long-term high-dose fluconazole treatment. In May of 2007, the patient presented to the Duke University hospital emergency room with seizures. Magnetic resonance imaging revealed two large CNS lesions found to be cryptococcomas based on brain biopsy. Prior chest CT imaging had revealed small lung nodules indicating that C. gattii spores or desiccated yeast were likely inhaled into the lungs and dissemination occurred to both the leg and CNS. The patient''s travel history included a visit throughout the San Francisco, CA region in September through October of 2006, consistent with acquisition during this time period. Cultures from both the leg and brain biopsies were subjected to analysis. Based on phenotypic and molecular methods, both isolates were C. gattii, VGI molecular type, and distinct from the Vancouver Island outbreak isolates. Based on multilocus sequence typing of coding and noncoding regions and virulence in a heterologous host model, the leg and brain isolates are identical, but the two differed in mating fertility. Two clinical isolates, one from a transplant recipient in San Francisco and the other from Australia, were identical to the North Carolina clinical isolate at all markers tested. Closely related isolates that differ at only one or a few noncoding markers are present in the Australian environment. Taken together, these findings support a model in which C. gattii VGI was transferred from Australia to California, possibly though an association with its common host plant E. camaldulensis, and the patient was exposed in San Francisco and returned to present with disease in North Carolina.     

Suicide in San Francisco: Reported and Unreported

Reported suicide in San Francisco was investigated for the period between July 1956, through June 1964. During that time 1664 persons killed themselves, according to the Coroner''s records. The method most frequently used was oral ingestion of toxic substances, which significantly deviates from national statistics, shooting being the method most frequently reported. The explanation for this deviation is probably the more valid mortality statistics of San Francisco, and from this it may be inferred that unreported suicide may be largely suicide by ingestion, unrecognized because of lack of postmortem studies.Unreported suicide is further classified into intentioned (masked, suppressed and undiscovered) and subintentioned (oral-dependent and aggressive).Despite the fact that suicide has been a leading cause of death, the public and the medical profession are largely apathetic. An attempt is being made by Suicide Prevention of San Francisco, Inc. to develop a clinical and research facility for the study and treatment of suicidal persons.     

Estimation of HIV infection and incubation via state space models

By using the state space model (Kalman filter model) of the HIV epidemic, in this paper we have developed a general Bayesian procedure to estimate simultaneously the HIV infection distribution, the HIV incubation distribution, the numbers of susceptible people, infective people and AIDS cases. The basic approach is to use the Gibbs sampling method combined with the weighted bootstrap method. We have applied this method to the San Francisco AIDS incidence data from January 1981 to December 1992. The results show clearly that both the probability density function of the HIV infection and the probability density function of the HIV incubation are curves with two peaks. The results of the HIV infection distribution are clearly consistent with the finding by Tan et al. [W.Y. Tan, S.C. Tang, S.R. Lee, Estimation of HIV seroconversion and effects of age in San Francisco homosexual populations, J. Appl. Stat. 25 (1998) 85]. The results of HIV incubation distribution seem to confirm the staged model used by Satten and Longini [G. Satten, I. Longini, Markov chain with measurement error: estimating the 'true' course of marker of the progression of human immunodeficiency virus disease, Appl. Stat. 45 (1996) 275].     

Vulnerability Analysis and Passenger Source Prediction in Urban Rail Transit Networks

Based on large-scale human mobility data collected in San Francisco and Boston, the morning peak urban rail transit (URT) ODs (origin-destination matrix) were estimated and the most vulnerable URT segments, those capable of causing the largest service interruptions, were identified. In both URT networks, a few highly vulnerable segments were observed. For this small group of vital segments, the impact of failure must be carefully evaluated. A bipartite URT usage network was developed and used to determine the inherent connections between urban rail transits and their passengers'' travel demands. Although passengers'' origins and destinations were easy to locate for a large number of URT segments, a few show very complicated spatial distributions. Based on the bipartite URT usage network, a new layer of the understanding of a URT segment''s vulnerability can be achieved by taking the difficulty of addressing the failure of a given segment into account. Two proof-of-concept cases are described here: Possible transfer of passenger flow to the road network is here predicted in the cases of failures of two representative URT segments in San Francisco.     

WORKMEN'S COMPENSATION ACT—Some Aspects of Interest to California Physicians

This article was prepared by Mr. William M. Whelan, Director of Special Services, California Medical Association, under the supervision of Dr. Francis J. Cox, Chairman of the Medical Services Commission of the Association, and Mr. Howard Hassard, the Association''s Legal Counsel. It is intended as a brief synopsis of the California Workmen''s Compensation Law as it applies to the physician in private practice. It is not an exhaustive treatment of the subject. A physician who desires to acquaint himself in detail with California industrial practice should consult the article entitled “The Physician''s Role in Workmen''s Compensation,” California Medicine, 82:352-362, April, 1955. Inquiries regarding industrial medicine should be addressed to Mr. William M. Whelan, California Medical Association, 450 Sutter St., San Francisco 8.     

Reemergence of the bedbug Cimex lectularius in Seoul, Korea

A healthy 30-yr-old woman carrying an insect that had been caught in her living room visited the International Clinic at Severance Hospital, Seoul, in December 2007. The insect she brought was identified to be a nymph of a bedbug, Cimex lectularius, and her skin rashes looked typical bedbug''s bites. Her apartment was investigated, and a dead body of a bedbug, cast skins, and hatched eggs were found in her rooms and neighbors'' rooms in the same building. She was living in that apartment in Seoul for 9 months since she had moved from New Jersey, USA. We assume that the bedbugs were introduced from abroad, since there had been no report on bedbugs in Seoul for more than 2 decades at least. This is a report of a reemergence of the common bedbug, C. lectularius in Seoul, Korea.     

A CMA position. Acquired immunodeficiency syndrome.

The following general principles serve as guidelines for various bodies, health care professionals and the general public. Specific aspects of infection with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) that relate to physicians'' ethical responsibilities as well as society''s moral obligations are discussed. Such matters include the need for education, research and treatment resources; the patient''s right to investigation and treatment and to refusal of either; the need to obtain the patient''s informed consent; the right to privacy and confidentiality; the importance of infection control; and the right to financial compensation in the case of occupational exposure to HIV.     

Are general practitioners ready to prevent the spread of HIV?

General practitioners are excellently placed to assess a person''s risk of being infected with the human immunodeficiency virus (HIV) and to give advice on reducing that risk. Their attitudes to the acquired immune deficiency syndrome (AIDS) and infection with HIV are, however, unknown. A questionnaire survey of 196 general practitioners in East Berkshire Health District was used to assess general practitioners'' readiness to undertake opportunistic health education to prevent the spread of infection with HIV. Altogether 132 replied. Sixty four of them expressed little interest in health education about HIV, and one in six would not dissent from the notion that AIDS could be controlled only by criminalising homosexuality. Only 75 of them had initiated discussions about HIV with patients. Moreover, many underestimated the risks from heterosexual sex while exaggerating the risks from non-sexual contact.Advice from general practitioners if given extensively might reduce the spread of infection with HIV. How best this may be achieved needs to be considered urgently.     

Distinguished Lecture in General Anthropology: The Anthropology of Trouble

This essay was presented as the Distinguished Lecture in General Anthropology at the 91st Annual Meeting of the American Anthropological Association, December 4, 1992, in San Francisco, California.