Unit 19

1. Выучите следующие слова и словосочетания:

1. disease — болезнь, заболевание

2. communicable - contagious — инфекционный, зараз­ный

3. outbreak — вспышка, внезапное появление

4. investigation — исследование, изучение

5. reveal — открывать, обнаруживать

6. unbiased — беспристрастный, объективный

7. exposure — воздействие

8. mortality — смертность, летальность

9. morbidity — заболеваемость; болезненность

10. causal relationship — причинная связь

11. outcome — результат, итог

12. transmission — передача, перенос

13. blood — кровь

14. saliva — слюна

2. Прочитайте и переведите следующие интернациональные слова:

epidemiology, epidemiologist, epidemics, collection, analysis, fac­tor, model, process, discipline, philosophy, informatics, sociology, so­cial, biology, biological, chemicals, risk, alcohol, stress, agent, medi­cal, viral, virus, horizontal, vertical, mechanism, infect, infected, in­fection, symptom, period, incubation, individual, region, proportion.

3. Прочитайте текст и ответьте на следующие вопросы.

1. What is epidemiology?

2. What does work of epidemiologists consist of?

3. What is the purpose of epidemiological studies?

4. What is the difference between vertical and horizontal vi­rus transmission?

5. What goes first: period of communicability or incubation period?

6. What is more serious: epidemics or pandemics?

Epidemiology

Epidemiology is the study of factors affecting the health and illness of populations. In the work of communicable and non- communicable diseases, the work of epidemiologists range from outbreak investigation to data collection and analysis including the development of statistical models. Epidemiologists may draw on a number of other scientific disciplines such as biology in un­derstanding disease processes and social science disciplines in­cluding sociology and philosophy in order to better understand risk factors.

Epidemiological studies are aimed, where possible, at revealing unbiased relationships between exposures such as alcohol or smok­ing, biological agents, stress, or chemicals to mortality or morbidity. Identifying causal relationships between these exposures and out­comes are important aspects of epidemiology. Modern epidemiolo­gists use informatics as a tool.

Viral epidemiology is the branch of medical science that deals with the transmission and control of virus infections in humans. Transmission of viruses can be vertical, that is from mother to child, or horizontal, which means from person to person. Examples of ver­tical transmission include hepatitis В virus and HIV (human im­munodeficiency virus) where the baby is born already infected with the virus. Horizontal transmission is the most common mechanism of spread of viruses in populations. Transmission can be exchange of blood by sexual activity, e. g. HIV, hepatitis В and hepatitis C; by mouth by exchange of saliva, e. g. Epstein Barr virus, or from con­taminated food or water, e. g. norovirus; by breathing in viruses in the form of aerosols, e. g. influenza virus; and bv insect vectors such as mosquitoes, e. g. dengue.

Epidemiology is used to break the chain of infection in populations during outbreaks of viral diseases. Most viral infections of humans and other animals have incubation periods during which the infec­tion causes no signs or symptoms. Incubation periods for viral diseases range from a few days to weeks but are known for most infections. Following the incubation period there is a period of communicability; a time when an infected individual or animal is contagious and can infect another person or animal. This too is known for many viral in­fections and knowledge the length of both periods is important in the control of outbreaks. When outbreaks cause an unusually high pro­portion of cases in a population, community or region, they are called epidemics. If outbreaks spread worldwide, they are called pandemics.