University Report: Investigating Communicable Disease Epidemiology

This report examines various aspects of communicable diseases, beginning with an analysis of Staphylococcus food poisoning and the role of carriers in disease transmission. It delves into the spread of HIV through shared syringes, highlighting the virus's mechanism of action and reservoirs within the body. The report then explores the relationship between immunogenicity, transmissibility, and antigenic variation in endemic areas, emphasizing how pathogens evade the immune response. Furthermore, it discusses poliomyelitis, its transmission, and the clinical and subclinical ratios in endemic cases. The report also provides preventive measures for hepatitis A in workplaces and discusses the guidelines provided by the Western Australian Department of Health for sexually transmitted infections (STIs), including Gonorrhea. It covers antibiotic resistance, control methods like condom use and testing, and the application of sensitivity, specificity, and predictive values in disease surveillance. Finally, it analyzes the asymptomatic rates of Gonorrhea in men and women and provides examples of sensitive and specific case definitions for communicable diseases.

Running head: COMMUNICABLE DISEASE
Communicable disease
Name of the student
Name of the University
Author’s note

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Table of Contents
Section1...........................................................................................................................................2
Section2...........................................................................................................................................3
Section3...........................................................................................................................................4
References........................................................................................................................................8

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Section1
1.1 The outbreak of Staphylococcus food poisoning when traced back with the two kitchen
staffs. One was well but has positive pathogen detected in the nasal swab but other has a septic
finger. (Derde, et al, 2014). Between the two one that is well and has positive swab infection is
said to be colonized among the two carriers this is because the colonization of the microbes take
place is that after infection even if it grows in the body, it do not cause any symptoms.
1.2 If the syringe of H.I.V positive user is shared, then H.I.V will spread. The H.I.V virus is the
source. Transmission of the disease occurs when any normal person uses the same syringe of the
infected person. The latent H.I.V viruses have the reservoirs in the immune cells. The reservoirs
can be found throughout the body including brain, lymph nodes, blood and even in the digestive
glands. After entering the body the virus inserts their genetic blueprint, D.NA into the host
immune cells such as the CD4 cells. It remains latent when it manufactures the proteins. After
the proteins are produced, the immune system gets totally disrupted.
1.3 In any endemic area, when other influences are equal, immunogenicity is inversely
proportional to the transmissibility. This is because the speed with which the immunity develops
in the population is inversely related.
1.4 Immunogenicity is the ability of the organism to produce the immune response and
provides shielding affect against reinfection. In endemic conditions the immunogenicity becomes
thus inversely proportion to the transmission because as the immune response increase in a
population, the less will be the expression of the infections and less will be the spread of the
disease in a population.
1.5 The reason behind the influence of the antigenic variation and the immunogenicity is that
when antigenic variation occurs the pathogens can change their surface proteins in order to evade

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the immune response of the host (Coscolla et al, 2015). Antigenic variation not only causes
immune evasion by the pathogens but also allows the re infection for the pathogens. This is
because due to antigenic variation their antigens are no longer recognized by the host immune
response. When any organism is exposed to any antigen then it produces antibodies and the
immune response is generated. Thus with antigenic variation, there is the alteration of the
proteins and carbohydrate molecules. If there is genetic variation, there will be the antigenic
variation that will support the acquired immune response.
Section2
2.1 a. Poliomyelitus is the virus transmitted infectious disease. This mainly affects the children.
The virus is spread between the persons mainly through the faecal oral route as given in the case
study. Since the virus invades the nervous system paralysis occurs. In the endemic case, it mainly
affects a particular age group because at the age below 5 the children are in the process of
acquiring immunity, as a result, the immune response is not that strong to resist the attack of the
foreign pathogens of polio. However the pathogenicity does increase with age, Again infection
is followed by lifelong strain specific immunity.
b. The clinical and subclinical ratio will give the approximate estimation of the symptomatic and
asymptomatic individuals in a population for any endemic infectious disease.
2.2 After knowing the scenario of hepatitis infection, it can be known that hepatitis mainly
infects the adult population than the children. The spread of hepatitis A occurs widespread in the
Australian and American adults in the workplace. So while advising the Community Aid
Abroad, the protection of the overseas working environment, the preventive measures can be
suggested to them (Mohd Hanafiah et al, 2013). The blood awareness alert which by making
them know about the spread of the pathogen through the blood. They must be given advice on

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the use of protective barriers like the gloves, gowns, masks. The protective measures will reduce
the risk of exposure of the health care worker’s skin or mucus membrane.
For individual worker, they can be also given advice the use of protective barriers while working
in the workplace.
Section3
Sexually transmitted infections are blood borne and they are of significant health concerns in
Australia. It is the part of continued response to the Western Australian Department of health.
They update the clinical guidelines for the promotion of best practice for the management of
health issues related to sexually transmitted. They provide specialized advice for the HIV and
other STD (Villarino, et al, 2015). They contain the most updated version of the evidence based
practice and recommendations that the professionals can launch to control the diseases. They
provide the wide range of testing and treatment facilities (Des Jarlais et al, 2015).
The blue book gives the guidelines for control of infectious diseases in Australia that has been
published with the help of Communicable diseases prevention and control units of the Victorian
department of Health that assist the practitioners of the health departments in control and
prevention of the infectious diseases. They provide the guidelines of the requirements and the
notification of cause of infectious disease. They even identify the infectious agents of the
diseases (Sharland et al, 2016). The incubation period, reservoir, latent period, mode of
transmission, the period of communicability, susceptibility, and resistance are given for any
infectious disease. They inform about the control measures for patients and contact and the
outbreak measures to prevent an endemic condition.
The control of communicable disease manual is the book that refers to the identification and
control of any infectious disease. The public health is always concerned with the control of

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communicable diseases. This will provide the most updated version of the control measures that
can be taken to resist the outcome. This book very well explains the infection and transmission
of the leading Zika virus that has developed recently. They will give the views in the strategic
development of the guidance based latest science and help in managing the public health
professionals.
3.1 Gonorrhea is a sexually transmitted infection that is caused by the pathogen Neisseria
gonorrhoea, the agent of the disease. This coffee bean shaped diplococci bacteria cause the
pathogenesis in the environment through the sexually transmitted infection. The bacteria cause
pelvic inflammation of women and causes infertility.
3.2 The NT and STI Control of the guidelines recommend the antibiotic treatment which is
immediate for the high risk and symptomatic people affected with Chlamydia and gonorrhoea,
without the wait for the confirmatory tests to be done. This has helped to prevent the disease
because the antibiotic kills the bacteria before it changes into its virulent nature after integrating
its DNA prints into the host. The symptoms naturally develop not before 30 days. The latent
period of the bacteria is due to the insertion of its genetic material into the host genome. But the
prevention procedure has helped a lot to prevent the outcome of the disease as the pathogens will
be killed beforehand and the symptoms will not emerge (Templeton et al, 2014).
The two other control methods for STI, they are the use of latex condoms, avoid sharing of the
towels, get tested for H.I.V. These can lot prevent the transmission of the sexually transmitted
bacteria s most of the bacteria is transmitted by the fluid and blood contact with the infectious
person.
3.3 The increase of gonorrhea in the population may have been due to the sexual contact with the
infected person and the antibiotic resistance of the bacteria (Ventola, 2015). The antibiotic

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resistance has failed to kill the disease in time as a result of the increase in infection, greater has
been its transmissibility. Even the higher dose of ceftriaxone by injection and other antibiotics
have not shown the preventive effects, as a result, the infectious disease ruled with pathogenesis
and also became communicable.
3.4
Disease number Non disease number Total
Positive number 750 150 900
Negative number 50 9050 9100
total 800 9200 10,000
Sensitivity- 750/ (750+50) * 100 = 93.75%
Specificity- 150/ (150+9050) * 100 = 1.63%
Positive predictive value- 750/ (750+150) * 100 = 83.33%
Negative predictive value- 9200/ (9200+800) * 100 = 92%
3.5 a)The percentage of asymptomatics of women and men for gonorrhoea will give the ability
to define the case in a population that is notified to get affected. It will give the warning system
to detect the outbreak. It is a very practical approach to identify the communicable disease by
increasing the number of false positive. Thus the percentages of the asymptomatic for the men
and women will give the sensitivity in the surveillance of a disease.

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b) In the epidemiological characteristics, the apparent asymptomatic rates of men and women
refer that women in the population are less affected than male. The male has the more chance in
that population to be affected with gonorrhea.
c) For sensitive case definition, the example for a communicable disease can be chicken pox and
hepatitis. This disease surveillance is based on the proportion of actual cases in a population.
D) For specific case definition, the communicable disease that can be used is H.I.V because it
depends on the specific agent. It will give the more accurate description for the cases but at the
expense of missing true cases.

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References
Coscolla, M., Copin, R., Sutherland, J., Gehre, F., de Jong, B., Owolabi, O., ... & Gagneux, S.
(2015). M. tuberculosis T cell epitope analysis reveals paucity of antigenic variation and
identifies rare variable TB antigens. Cell host & microbe, 18(5), 538-548.
Derde, L. P., Cooper, B. S., Goossens, H., Malhotra-Kumar, S., Willems, R. J., Gniadkowski,
M., ... & Aragão, I. (2014). Interventions to reduce colonisation and transmission of
antimicrobial-resistant bacteria in intensive care units: an interrupted time series study
and cluster randomised trial. The Lancet infectious diseases, 14(1), 31-39.
Des Jarlais, D. C., Nugent, A., Solberg, A., Feelemyer, J., Mermin, J., & Holtzman, D. (2015).
Syringe service programs for persons who inject drugs in urban, suburban, and rural areas
—United States, 2013. MMWR Morb Mortal Wkly Rep, 64(48), 1337-41.
Mohd Hanafiah, K., Groeger, J., Flaxman, A. D., & Wiersma, S. T. (2013). Global epidemiology
of hepatitis C virus infection: New estimates of age‐specific antibody to HCV
seroprevalence. Hepatology, 57(4), 1333-1342.
Sharland, M., Butler, K., Cant, A., Dagan, R., Davies, G., de Groot, R., ... & Giaquinto, C.
(Eds.). (2016). Manual of childhood infections: the blue book. Oxford University Press.
Templeton, D. J., Read, P., Varma, R., & Bourne, C. (2014). Australian sexually transmissible
infection and HIV testing guidelines for asymptomatic men who have sex with men
2014: a review of the evidence. Sexual Health, 11(3), 217-229.

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Ventola, C. L. (2015). The antibiotic resistance crisis: part 1: causes and threats. Pharmacy and
Therapeutics, 40(4), 277.
Villarino, M. E., Scott, N. A., Weis, S. E., Weiner, M., Conde, M. B., & Jones, B. (2015). for the
International Maternal Pediatric and Adolescents AIDS Clinical Trials Group
(IMPAACT) and the Tuberculosis Trials Consortium (TBTC). Treatment for preventing
tuberculosis in children and adolescents: a randomized clinical trial of a 3-Month, 12-
dose regimen of a combination of rifapentine and isoniazid. JAMA Pediatr, 169(3), 247-
255.