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Biomedical subjects

T Habtemariam

Publications and source records attributed to T Habtemariam.

7 recordsLinked to original sources
PubMed2001

Modelling viral and CD4 cellular population dynamics in HIV: approaches to evaluate intervention strategies.

Computational models, such as in epidemiology, provide a powerful tool that can be used to systematically examine an array of dynamic interactions among populations as well as to evaluate altemate disease intervention strategies. The specific objectives in this study were to: a/ examine the interaction of cellular (CD4) and HIV population dynamics and evaluate the impact of the use of combination chemotherapies on viral and CD4 populations (Experiment #1), b/ demonstrate how modelling can be used to evaluate the impact of an intervention (condom use) on reducing the rate of HIV/AIDS (Experiment #2). In this study, we used state transition models and conducted simulation experiments to evaluate various alternatives for the control and/or prevention of HIV/AIDS. The result indicated that combination therapy (double or triple drug therapies) was very effective. The HIV viral population decreased rapidly and remained suppressed for years. On the other hand, the CD4 cell population increased above 400 cells per ml and was maintained above that level for many years. Mono-therapy was not as effective; although the viral load decreased rapidly, it increased to its original levels within a few months. Since condom use is one of the key interventions of HIV/AIDS, we evaluated its use in 25%, 50% and 75% of an adult, sexually active population. Increasing condom use by 50% and 75% above an estimated baseline of 25% reduced the incidence of AIDS by 53% in Blacks, 49% in Hispanics and 43% in Whites. The study shows how a cellular/molecular level model can be incorporated within a macro-epidemiologic systems dynamics model to evaluate a variety of scientific questions such as to see if cellular/molecular level interventions reduce morbidity and mortality rates in HIV.

Anti-HIV Agents↗
PubMed1997

A risk-assessment model for foot and mouth disease (FMD) virus introduction through deboned beef importation.

We present a risk-assessment model to assess the risk of introduction of foot and mouth disease (FMD) virus associated with deboned beef importation. The model was developed in accordance with the risk-reduction procedures proposed by the European Community for meat importation. The risk reduction procedures include farm-level inspection, ante-mortem inspection, post-mortem inspection, chilling and deboning. The risk assessment was based on the prevalence of FMD-infected cattle in herds as well as the prevalence of infected herds in the exporting country. Computer simulations were carried out to evaluate the probability of FMD virus introduction by importing 100 tons of deboned beef in relation to FMD prevalence, number of cattle selected from each herd, and sample sizes in ante-mortem and post-mortem inspections. The effects of the risk-reduction procedures on the probability of FMD virus introduction were examined.

Animals↗
PubMed1989

Utility of epidemiologic simulation models in the planning of trypanosomiasis control programs.

To understand the behavior of complex epidemiologic systems, it is useful to devise computer based simulation models by approximating the interactions via biomathematical expressions. Without doubt, these models could be over simplifications of complex interactions but they could be useful in comparison to classical laboratory and/or field experimental approaches which may not be practical or feasible. In the past obtaining solutions to biomathematical equations with any degree of complexity has been impossible. However, the availability of powerful computers has now made the quantitative analysis of such systems feasible and indeed practical. With this in mind, research to develop computer simulation models involving Trypanosoma has been underway at Tuskegee University. Based on static and dynamic computer models, several alternatives for the control of trypanosomiasis have been examined. The integration of multivariate, systems analysis and optimization models in epidemiologic problem solving and decision making pertaining to the trypanosome-tsetse complex has been valuable. Its potential application to other epidemiologic problems is an asset that should be exploited in future analytical studies.

Algorithms↗
PubMed1983

A computer based decision-making model for poultry inspection.

In an attempt to develop a predictive model for poultry inspection at processing plants, a systems research design was developed to examine poultry population health dynamics from hatching to processing. Five cooperating Alabama poultry firms with 5 to 7 growers from each firm were identified to form the study unit. The farms were stratified to represent good, average, and poor producers. Via epidemiologic causal diagrams, variables with potential influence on poultry condemnation due to diseases were identified for hatchery, broiler, and processing subsystems. Field and/or laboratory data were generated for each study unit and for each variable. Using stepwise multiple regression and discriminant analysis, a predictor model with a multiple correlation coefficient (R) of 0.91 and multiple coefficient of determination (R2) of 0.82 was developed. A discriminant analysis model for classifying a flock into high or low condemnation group, using 0.1% to 2.0% as the demarcation line, was also developed. This latter model had overall correct classification probabilities ranging from 0.88 to 1.0. The 2 decision-making models were then computerized, using Beginner's All-purpose Symbolic Instruction Code (BASIC). On the day of processing, the grower provides the inspector with selected information, which is entered on a computer. Alternatives for scaled-down inspection or others are then systematically evaluated by the computer, and decision-making information is provided to the user.

Alabama↗
PubMed1983

Automobile accidents in Illinois veterinarians.

Interviews to solicit information on total automobile or truck travel, occupation related travel and automobile accidents were completed on 1082 non-military veterinarians in Illinois in 1969. Most had driven between 10,000 and 19,999 miles the previous year. Of the 1082 veterinarians interviewed, 313 had been in a total of 416 automobile accidents; of which 228 had been in only 1 accident, 69 in 2 accidents, 14 in 3 accidents and 2 veterinarians had 4 accidents each. the frequency of automobile accidents correlated directly with the number of work-related miles driven. Large animal, general practice and government employed were the three practice types with most miles traveled and greatest percent of miles traveled which were occupationally related. Veterinarians who had been in one or more automobile accidents differed from the total veterinary population in that fewer were married, veterans, smokers, had consulted a physician concerning their health the last six months or had been sick following insecticide use. Searches of death certificates indicated that 14 Illinois veterinarians had died as a result of vehicular accidents between 1950 and 1973, a figure similar to the rate in Illinois white males.

Accidents, Traffic↗
PubMed1981

The health characteristics of veterinarians in Illinois.

A descriptive study was conducted in 1967, 1968, and 1969 on some of the basic health characteristics of the approximately 1,100 veterinarians in Illinois. A total of 87% had consulted a physician concerning their health within the past 30 months. Within the past 18 months 47% had been vaccinated against tetanus. Over one-third of the veterinarians had received their last tetanus inoculation because of an injury. Thirty-one percent had been tested serologically for zoonotic infections other than at a meeting of the state veterinary association, 69% wore glasses, 12% were allergic to an antimicrobial, and 24% had a history of an appendectomy. Nearly one-half smoked and another 22% were former smokers. Thirteen percent had hernias with 67% of these repaired surgically. The males of the subpopulation of veterinarians had a mean height of 5 feet 6 1/2 inches and a mean weight of 179 pounds. Gastrointestinal ulcers had been diagnosed in 10%, arthritis in 11%, heart disease in 8%, hypertension in 7%, diabetes in 2% and cancer in 1%. Sixty-eight percent had not lost a single workday in the past year. The total group had a mean loss of 0.85 days due to accident and 4.09 due to illness.

Accidents↗