Quantitative risk assessment of entry of contagious bovine pleuropneumonia through live cattle imported from northwestern Ethiopia.

Contagious bovine pleuropneumonia (CBPP) is a highly contagious bacterial disease of cattle caused by Mycoplasma mycoides subspecies mycoides small colony (SC) bovine biotype (MmmSC). It has been eradicated from many countries; however, the disease persists in many parts of Africa and Asia. CBPP is one of the major trade-restricting diseases of cattle in Ethiopia. In this quantitative risk assessment the OIE concept of zoning was adopted to assess the entry of CBPP into an importing country when up to 280,000 live cattle are exported every year from the northwestern proposed disease free zone (DFZ) of Ethiopia. To estimate the level of risk, a six-tiered risk pathway (scenario tree) was developed, evidences collected and equations generated. The probability of occurrence of the hazard at each node was modelled as a probability distribution using Monte Carlo simulation (@RISK software) at 10,000 iterations to account for uncertainty and variability. The uncertainty and variability of data points surrounding the risk estimate were further quantified by sensitivity analysis. In this study a single animal destined for export from the northwestern DFZ of Ethiopia has a CBPP infection probability of 4.76×10(-6) (95% CI=7.25×10(-8) 1.92×10(-5)). The probability that at least one infected animal enters an importing country in one year is 0.53 (90% CI=0.042-0.97). The expected number of CBPP infected animals exported any given year is 1.28 (95% CI=0.021-5.42). According to the risk estimate, an average of 2.73×10(6) animals (90% CI=10,674-5.9×10(6)) must be exported to get the first infected case. By this account it would, on average, take 10.15 years (90% CI=0.24-23.18) for the first infected animal to be included in the consignment. Sensitivity analysis revealed that prevalence and vaccination had the highest impact on the uncertainty and variability of the overall risk.

Psychosocial factors as predictors of HIV/AIDS risky behaviors among people living with HIV/AIDS.

Infection with the human immunodeficiency virus (HIV) that causes acquired immunodeficiency syndrome (AIDS) is still rising globally. In order to develop effective HIV/AIDS risky behavior reduction intervention strategies and to further decrease the spread of HIV/AIDS, it is important to assess the prevalence of psychosocial problems and HIV/AIDS risky behaviors in people living with HIV/AIDS (PLWHA). The objective of this study is to assess the relationship between psychosocial variables and HIV/AIDS risky behaviors among PLWHA. A total of 341 questionnaires were distributed and 326 were fully completed and returned, 96% response rate. The relationships between the identified psychosocial and HIV/AIDS risky behaviors among PLWHA were analyzed using The Moment Structures software version 17.0 (SPSS Inc.) The results indicate that psychosocial health problems were significant predictors of HIV/AIDS risky behaviors in PLWA. Further cross-disciplinary research that addresses the manner in which psychosocial problems and HIV/AIDS risky behaviors interact with each other among PLWHA is needed.

A quantitative risk assessment of multiple factors influencing HIV/AIDS transmission through unprotected sex among HIV-seropositive men.

The objective of this study is to conduct a quantitative risk assessment of multiple factors influencing HIV/AIDS transmission through unprotected sexual practices among HIV-seropositive men. A knowledgebase was developed by reviewing different published sources. The data were collected from different sources including Centers for Disease Control and Prevention, selected journals, and reports. The risk pathway scenario tree was developed based on a comprehensive review of published literature. The variables are organized into nine major parameter categories. Monte Carlo simulations for the quantitative risk assessment of HIV/AIDS transmission was executed with the software @Risk 4.0 (Palisade Corporation). Results show that the value for the likelihood of unprotected sex due to having less knowledge about HIV/AIDS and negative attitude toward condom use and safer sex ranged from 1.24 × 10(-5) to 8.47 × 10(-4) with the mean and standard deviation of 1.83 × 10(-4) and 8.63 × 10(-5), respectively. The likelihood of unprotected sex due to having greater anger-hostility, anxiety, less satisfied with aspects of life, and greater depressive symptoms ranged from 2.76 × 10(-9) to 5.34 × 10(-7) with the mean and standard deviation of 5.23 × 10(-8) and 3.58 × 10(-8), respectively. The findings suggest that HIV/AIDS research and intervention programs must be focused on behavior, and the broader setting within which individual risky behaviors occur.

The Association between Interrelationships and Linkages of Knowledge about HIV/AIDS and its Related Risky Behaviors in People Living with HIV/AIDS.

The relationship between knowledge about HIV/AIDS and its associated risky behaviors is complex and has not been sufficiently explored. It is especially important to look at some of the aspects of this relationship among people living with HIV/AIDS (PLWHA) in order to develop effective intervention strategies to reduce HIV/AIDS risky behaviors. The objective of this study was to investigate the association between knowledge about HIV/AIDS and its risky behaviors among PLWHA. METHODS: Risk taking behavior among the participants was measured as the number of all risky behaviors before and after the knowledge of their HIV/AIDS positive status. Knowledge was measured by the extent to which participants answered the HIV/AIDS related questions. The relationships between the identified HIV/AIDS risky behaviors and the knowledge among PLWHA were analyzed using Structural Equation Modelling. RESULTS: 341 questionnaires were administered and 326 (96%) were completed and returned from PLWHA clients of HIV/AIDS outreach facility in Alabama. Analysis revealed that, knowledge of HIV/AIDS, and knowledge of a properly used condom in preventing the infection through sexual activity were positively related with knowledge of where to get tested for HIV/AIDS. Using drugs before sex was significantly related with having sex with prostitutes (total effects' standardized regression coefficient (TESRC)=0.29, p<0.001). Sharing the same syringe or needle with another person or other people to inject oneself was strongly related with number of sexual partners within one year (TESRC=0.25, p<0.001), and sex with injecting drug users (TESRC=0.45, p<0.001). CONCLUSION: A deeper understanding of HIV/AIDS and some of its transmission pathways appears to be very effective in practicing the taking of preventive measures such as using condoms or getting tested for HIV. Increasing access to HIV/AIDS education could therefore be very useful in providing further gains in HIV/AIDS awareness among PLWHA.

The association between religious affiliation and frequency of attendance at religious services on HIV risky behaviors among people living with HIV/AIDS.

The purpose of this study was to examine if religious affiliation and frequency of attendance at religious services were associated with HIV risky behaviors among people living with HIV/AIDS (PLWHA). The participants are HIV positive clients of a community based HIV/AIDS outreach facility (CBHAOF) located in Montgomery, Alabama, USA. The participants completed the questionnaire during their medical visits to the clinic at their own convenience and that of the facility's staff. A total of 341 questionnaires were distributed to PLWHA and 326 (96%) were fully completed and returned. There were more male than female participants (56 versus 42%). The majority of the respondents (67%) were between 30 and 49 years of age. Nearly two thirds of the participants (64%) were African Americans whilst 36% were other races combined (White = 29%, Hispanic = 3% and other races = 4%). A chi-square test was used to examine the association between selected variables. Findings show substantial variations of selected HIV risky behaviors according to religious affiliation and frequency of attendance at religious services (p < 0.05). The study findings suggest the importance of religious affiliation and frequency of attendance at religious services in reducing HIV risky behaviors among PLWHA. The findings have implications for HIV/AIDS prevention and we recommend that it is important to incorporate Faith-based organizations in the global fight against HIV/AIDS.

The Role of Computational Epidemiology and Risk Analysis in the Fight Against HIV/AIDS.

Substantial progress in the understanding of HIV and CD4 cell dynamics using computational models undergirded by sound epidemiologic and mathematical principles has been achieved. The early stages of the applications of these models were based on relatively simple mathematical models that considered the body as a one-compartment system. In spite of these models attractiveness due to the experimental and/or mathematical standpoints, the underlying simplification neglected a lot of important factors affecting the population dynamics both on macro (human) and micro (cellular) population levels. This simplification also affected the kinetics linked to the immunology, infection and chemotherapy dynamics throughout the host. Epidemiologic research involves the study of a complex set of host, environmental and causative agent factors as they interact to impact health and diseases in any given population whether biotic or abiotic. This leads in generating large data sets which require the use of powerful computational methods for studying these large and complex models by means of computational epidemiologic methods. Another dimension of a great challenging problem to public health decision makers is that of emerging diseases, as they have to face and deal with a lot of uncertainty at the early stages of disease outbreaks. However, at this juncture, epidemiologic problem-solving and decision-making often proceeds in the face of uncertainties and limited information. One methodology to address these types of shortcomings is the application of risk analysis. Risk analysis is a process for decision making under uncertainty that consists of three fundamental tasks: risk management, risk assessment, and risk communication. Excitingly, the prospective role that computational models and risk analysis may possibly play in the advancement of the theoretical understanding of disease processes and the identification of specific intervention strategies holds the potential to impact and save human lives.

A comparative study of substance use before and after establishing HIV infection status among people living with HIV/AIDS.

OBJECTIVE: To determine if significant differences exist in substance use among people living with HIV/AIDS (PLWHA) before and after establishing their HIV infection status. METHOD: The study participants are HIV positive clients of a community based HIV/AIDS outreach facility located in Montgomery, Alabama. The questionnaire includes demographics, substance use and risky sexual behaviors pertaining to HIV transmission. Each participant completed an anonymous questionnaire. A total of 341 questionnaires were distributed and 326 were fully completed and returned, representing a response rate of 96%. RESULTS: Findings revealed a statistically significant difference in alcohol consumption before sex among PLWHA before and after establishing their HIV infection status (p = .001). No significant differences were observed among participants who reported as having used drugs intravenously (p = .89), and among those sharing the same syringe/needle with another person (p = .87) before and after establishing their HIV infection status. CONCLUSION: There is continued substance use and alcohol consumption before sex among PLWHA after establishing their HIV status despite clear evidence of such risky behaviors that could lead to an increase in exposure to HIV.

Applying the epidemiologic problem oriented approach (EPOA) methodology in developing a knowledge base for the modeling of HIV/AIDS.

INTRODUCTION: In the epidemiologic modeling of diseases, the epidemiologic problem oriented approach (EPOA) methodology facilitates the development of systematic and structured knowledge bases, which are crucial for development of models. A detailed understanding of the epidemiology of a given disease provides the essential framework for model development and enables the laying out of the comprehensive and fundamental structures for the models. OBJECTIVE: To develop such a knowledge base for developing HIV/AIDS models. METHODS: The EPOA methodology was utilized to develop the knowledge base for HIV/AIDS; it is composed of six pillars within two triads: the Problem Identification/Characterization and the Problem Management/Solution/Mitigation Triads, interlinked by the diagnostic procedure. RESULTS: Using information from various sources, the triads are decomposed into their respective pillar variables and parameters. The agent pillar identifies the causative agent (HIV) and its characteristics. The host pillar identifies and characterizes the host (human). The environment pillar characterizes the physical, biological and socioeconomic environments for both the host and agent. The therapeutics/treatment pillar considers the treatment options for HIV/AIDS. The prevention/control pillar considers prevention and control measures. The health maintenance/health promotion pillar considers measures for the health maintenance of the population. CONCLUSION: Models for HIV/AIDS can be conceptual, in vivo or in vitro, systems analysis, mathematical, or computational just to name a few. The knowledge base developed using the EPOA methodology provides a well-organized structured source of information, which is used in the variable and parameter estimations as well as analysis (biological, mathematical, statistical and computer simulations), which are crucial in epidemiologic modeling of HIV/AIDS. EPOA methodology has become an important tool in the development of models that can enlighten decision making in public health.

Assessing HIV/AIDS intervention strategies using an integrative macro-micro level computational epidemiologic modeling approach.

INTRODUCTION: Epidemiologic research involves the study of a complex set of host, environmental and causative agent factors as they interact to impact health and diseases in any population. The most advanced of these efforts have focused on micro (cellular) or macro (human) population level studies but lacked the integrative framework as presented in this article. Modeling the cumulative impact of HIV/AIDS at the cellular, molecular, and individual behaviors at the population-level can be complex. The main objective of our research is to develop a macro-micro level computational epidemiologic model that integrates the dynamic interplay of HIV/AIDS at the cellular and molecular level (micro-epidemiologic modeling), and the dynamic interplay of multifactorial determinants: biomedical, behavioral, and socioeconomic factors at the human population level (macro-epidemiologic modeling). METHODS: The computational epidemiologic model was constructed using systems dynamics modeling methodology. The dynamics of the relationships was described by means of ordinary/partial differential equations. All state equations in the model were approximated using the Runge-Kutta 4th order numerical approximation method. RESULTS: Computational tools and mathematical approaches that integrate models from micro to macro levels in a seamless fashion have been developed to study the population-level effects of various intervention strategies on HIV/AIDS. The critical variables that facilitate transmission of HIV and intracellular interactions and molecular kinetics were examined to assess different interventions strategies. Such multilevel models are essential if we are to develop quantitative, predictive models of complex biological systems such as HIV/AIDS.

The correlation between alcohol consumption and risky sexual behaviors among people living with HIV/AIDS.

The objectives of this study were to determine if significant correlation exists between drinking any alcoholic beverage and risky sex among 326 AIDS patients. Participants completed anonymous surveys. The result of the regression and Pearson Correlation analyses revealed a significant positive correlation between drinking alcohol before sex and frequency of condom use (p < .0001). The number of sex partners respondents reported was also correlated with the frequency of alcohol use (p = .003). The result shows that the quantity of alcohol consumption was correlated with two indicators of risky sex: having multiple sexual partners (p < .0001) and having sexual intercourse without a condom (p < .001). Interventions are that integrate HIV risk reduction with alcohol risk reduction is very useful to minimize the risk of new HIV infections and/or manage existing infections.

Conspiracy beliefs about HIV/AIDS among HIV-positive African-American patients in rural Alabama.

This is apparently the first survey examining endorsement of HIV/ AIDS conspiracy beliefs and their relations to educational attainment among 205 HIV-positive African-American patients receiving care at an AIDS Outreach Organization in Alabama. 31% somewhat or strongly believed that, "AIDS is a form o genocide against African Americans," 29% strongly agreed that "AIDS was created by the government to control the black population," 56.1% agreed that the government is withholding a cure for AIDS, and 69.8% agreed that the government is withholding information about the disease from the public. 52% agreed that "HIV is a manmade virus," and 43.1% that "AIDS was produced in the governments laboratory." Respondents with high school or college education were less likely to endorse conspiracy liefs. Being open and sensitive to questions about conspiracy beliefs plus understanding the historical roots and social context from which such questions arise in African-American communities is needed to counter such beliefs.

Computational Modelling of Intracellular Viral Kinetics and CD4+ Cellular Population Dynamics of HIV/AIDS.

Computational microepidemiologic modelling can facilitate the understanding of complex biomedical systems. It provides novel methods for quantitatively studying population health dynamics from the micro level of genomes and molecules to the higher macro levels such as HIV/AIDS in humans. Untangling the dynamics between the human immunodeficiency virus-1 (HIV-1) and CD4(+) lymphocyte populations and intracellular molecular kinetics of interactions in an integrative systems dynamics approach can help to understand the effective points of interventions in the HIV life cycle. With that in mind, we have developed a stochastic systems dynamics model that includes intracellular molecular level interactions. A sequence of events, molecular interactions and cytochemical kinetics are triggered when the HIV infects a CD4(+) lymphocyte. The full sequence of molecular level dynamics includes: attachment and fusion; reverse transcription; integration; transcription; translation; and budding or release of new virus. The newly released virus circulates back and infects a new CD4(+) lymphocyte and the cycle continues repeatedly. Mathematical models that account for these processes were developed. The model developed provides insights into how an intracellular/molecular level model can be incorporated within a macro-epidemiologic integrative systems dynamics model for examining a variety of computational experimentations. Such experimentations can help in evaluating scientific questions related to effective strategies in HIV drug therapy interventions.

PERCEPTIONS OF HIV AND PREVENTION EDUCATION AMONG INMATES OF ALABAMA PRISONS.

A 3-year interactive and passive training for HIV prevention education was conducted for 2,600 prisoners; 1,404 (54%) black, 1,092 (42%) white and 204 (4%) Hispanic. Less than 520 (20%) of inmates knew all the routes of HIV transmission. A post-presentation test showed that 96% became aware of HIV/AIDS transmission and can better protect themselves. Skin infections caused by Staphylococcus aereus were reported and manifested clinically as pustules, cellulites, boils, carbuncles or impetigo. Though no systemic infection was involved, staphylococcal infections suggest lowered immunity, an indicator to undiagnosed HIV. This study purposefully provides HIV prevention education model for prison health educators.