Both kinds of study are useful, the first yielding understanding of the behavior of disease in time and space and the second using that understanding to regulate disease. This book is constructed with scientific building blocks. But, from the beginning, the uses of concepts to understand and control disease are emphasized, often through examples. As we progress, more attention is paid to practical matters.
Fields of the study
This science can tackle man, plant or animal epidemic phenomenon through a limited course of time.
The discipline of epidemiology also embraces the areas of , and Ecology. Industrial Hygiene helps to identify, evaluate, and control workplace exposures to a variety of chemicals and agents. Toxicology aids in the evaluation of the dose of exposure and the response from each dose, largely relying on animal studies. Exposure and risk assessments are necessary to quantify the exposure, and help in the development of strategies to reduce exposures. , and .
These ecological studies help in the evaluation and understanding of the environmental impact as a result of exposures, whether to water, soils, humans or other animals in the environment.(1)
Trends in infectious syphilis; update on national data to
2003 and current epidemiological data
This study summaries the recent trends in infectious syphilis in England, Wales, and Northern Ireland. Thereport uses data from diagnoses made in genitourinary
medicine (GUM) clinics reported on the KC60 return.
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(1) Karanz,j.1974 .Epidemiology, concepts and scope page26.
Information on the epidemiology of infectious syphilis
in London is derived from the London enhanced
syphilis surveillance programmed co-ordinate by the
Health Protection Agency and collaborators.
The number of syphilis diagnoses made in
genitourinary medicine (GUM) clinics is the highest
seen since 1984, before the time of widespread
awareness of HIV/AIDS in the United Kingdom (UK).
In 2001, there were 1575 new diagnoses of primary and secondary infectious syphilis in GUM clinics; 783 in men who have sex with men (MSM),611 in
heterosexual males, and 181 in females (1).
Between 2002 and 2003, overall diagnoses of
Infectious syphilis rose by 24% in MSM, 32% in
heterosexual males, and 32% in females. England has
the highest rates of syphilis for both males and females.
Regionally, the biggest rises were seen in the
North East (253% in males), Wales (238% in males), and
the East Midlands (167% in males and females) (1).
The majority of cases are still seen in London (46%
and 59% in males and females respectively), followed
by the North West (15% and 7% in males and females
respectively).
Unlike other bacterial sexually transmitted
Infections (STIs), the burden of syphilis does not fall
upon teenagers. Increased rates have been seen in all
age groups with the exception of those aged under 16
years.
Syphilis outbreak
The resurgence in syphilis seen in the past five years has been accompanied by a number of outbreaks.
Syphilis outbreaks give an insight into factors underlying the change in syphilis epidemiology in the United Kingdom.
The characteristics of the UK syphilis outbreaks are very similar to those seen in western Europe and North
America and Australia, infection being associated with
high incidence areas, high rates of partner change
within risk groups, and concurrent HIV infection
The London enhanced syphilis surveillance
programmed is a health advisor led initiative that was
established in the 36 London GUM clinics in August
2001. Information on demographic, behavioral, and
clinical data is collected, giving a detailed insight into
the course of the London outbreak.
The London syphilis outbreak is the largest
outbreak reported to date in the UK. Between April
2001 and June 2004, 1775 diagnoses were reported, 1167
in MSM, and 370 and 222 diagnoses in heterosexual
males and females respectively . MSM tend to
older than heterosexuals with 41% aged between 35 and
44 years, whereas 36% of heterosexuals were aged
Rates of diagnoses of primary and secondary syphilis in GUM clinics by sex and country: 1995 to
The majority of cases were identified because the
patient was symptomatic or attending
routine screening. There was little reported contact
with other UK outbreak sites, 86% of infections in MSM
and 74% of infections in heterosexual males and females
were acquired in London. Of the heterosexual cases
23% were acquired outside the UK, almost half of these
cases were in people born in the Caribbean or Africa,
with only a small proportion being born in the UK.
Almost 90% of MSM diagnosed with syphilis were
of white ethnic origin and were born in the UK.
Heterosexuals were more likely to be of either white or
black ethnic origin, and more likely to be born outside
the UK .
Social venues, such as cruising grounds, saunas,
bars, and the Internet, were identified as important to
the acquisition of syphilis amongst MSM; 35% reported
using one or more venues. In contrast, only 7% of
heterosexual males and females reported using social
venues to meet sexual partners . Commercial
sex workers and their clients are important in
the heterosexual epidemic; 14% heterosexual men
reported contact with a CSW, and 14% of females
reported working as a CSW. Among MSM, only 3%
were CSWs themselves, or had contact with CSWs.
MSM reported a higher number of sexual partners
in the last three months .
Regional distribution of diagnoses and rates (per 100,000) of primary and secondary syphilis
infection by sex, England, Wales, and Northern Ireland*
syphilis by ethnicity and sexual orientation range between 0 and 76).
A high proportion of MSM had concurrent HIV
infection; 54% compared with only 7% of heterosexual
males and females. HIV status in MSM is associated
with stage of infection; with those who are HIV positive
being more likely to be diagnosed with secondary
syphilis. HIV positive men also were older,
reported higher numbers of sexual partners, and were
more likely to report using social venues to meet new
sexual partners.
Another country that is compared to UK is Germany. The study of this disease was done by the public health in Germany.
Public health officials said the incidence of syphilis was soaring in Germany, with homosexual men especially affected by the sexually transmitted disease, which is rampant in eastern Europe.
The Robert Koch Institute (RKI) in Berlin, the German federal agency that tracks infectious diseases, said there were 2,275 cases last year, a rise of 720 compared to 2001, with the highest rates in the two big cities of Berlin and Hamburg.
Officials said the increase was mainly because homosexual men were taking more risks. Often syphilis was showing up as an accompanying infection to human immunodeficiency virus, the agent that causes AIDS.
''Condoms do protect against infection, but are often not used in genital-oral contact where syphilis can be transferred,'' said Ulrich Marcus, an epidemiologist at the RKI.
As of 2002, 85 per cent of the reported cases were among men. The figures showed no increase among heterosexual patients.
Marcus said other European nations had reported increases too. ''There has been a very similar development in Britain,'' he said. However the rates were still well behind those in eastern Europe.
Experts believed Germany was often a first port of call in the spread of infection from the Balkan nations and the countries of the Commonwealth of Independent States (CIS).
Conclusion
The data confirm the continued evolution of the
syphilis epidemic in England, Wales, and Northern
Ireland. Key features include extension in MSM
populations within and outside metropolitan areas,
localization among CSWs London outbreak and their
clients with increasing heterosexual transmission. One
consequence of the latter includes the resurgence of
congenital syphilis, for which antenatal screening
programmes will require increased vigilance.
Another concern is the potential impact of syphilis
outbreaks on HIV transmission. This is of particular
concern among MSM populations that have a high HIV
prevalence and consequently there is a risk of
epidemiological synergy between syphilis and HIV.
The prevalence of HIV co-infection among MSM
diagnosed with syphilis has remained fairly constant
throughout the London epidemic, suggesting continued
transmission in these populations.
Altogether, these data point to worrying trends in
sexual health of MSM, migrants from high syphilis
prevalence countries, and CSWs and their clients.(1)
A necessary component of the development and implementation of effective public health strategies in the prevention and control of disease is adequate and accurate information on when, where, how and who is affected. Epidemiology is the study of patterns of disease occurrence in human populations in terms of time, place and persons, and the factors that influence these patterns.1 Observing and monitoring health and behaviour trends requires a surveillance system that captures useful data on those persons correctly identified with the characteristic under study and from which a descriptive epidemiologic profile can be formed. With this information, priorities can be identified and groups targeted for specific interventions based on their profile. It also allows for evaluation of interventions and the best use of resources in the management of the condition. This process relies on accurate identification of the condition (and its various stages) and a valid, reliable surveillance system with complete and accurate monitoring in a timely fashion.
(1) CDR Weekly Volume 14 No 31, 29 July 2004
A concern with any surveillance system is the quality of the data collected, including the degree of ascertainment of affected individuals.
Although some diseases and/or their risk factors may have a high prevalence in a population, the number of reported cases may greatly underestimate the number of persons with the condition. This may be due to a variety of reasons, e.g. poorly defined criteria for diagnosis, missed diagnosis, poorly designed surveillance systems, lack of awareness of the need to report or lack of health-seeking behaviour by those with the disease and/or risk factor.
Therefore, to determine the usefulness of any surveillance system, there must be some way of assessing the quality of the data and completeness of ascertainment. One approach that attempts to accomplish this is the capture-recapture (CR) method.(1)
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(1)Lillienfield A, Lillienfield DE. Foundations of epidemiology. 2nd ed. New York (NY): Oxford University Press, 1980.
References
- epidemiology &plant disease management,by Jan C.Zadoks &Richard D. Schein from Oxford university press 1979 p. 4 .
-
2-.
-
.
- Karanz,j.1974 .Epidemiology, concepts and scope page26
- CDR Weekly Volume 14 No 31, 29 July 2004
- 6-Lillienfield A, Lillienfield DE. Foundations of epidemiology. 2nd ed. New York (NY): Oxford University Press, 1980.
Index
Subject page
1 Introduction
1 What is epidemiology
Study designs 1
Definition of Epidemiology 2 2 Epidemiology and demographic Data
Importance of the study 2
Fields of the study 3
Syphilis outbreak 4
Conclusion 7
References 10