Tuberculosis: Causes, Treatment & Impact

This assignment delves into the multifaceted aspects of tuberculosis (TB). It examines epidemiological trends, highlighting risk factors associated with infection and disease progression. The document discusses various treatment approaches for TB, emphasizing challenges in managing drug-resistant strains. Furthermore, it analyzes the global impact of TB, encompassing its socioeconomic consequences and public health implications.

Running head: EPIDEMIOLOGY
EPIDEMIOLOGY
Name of the Student
Name of the University
Author Note:

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Contents
Answer 1:...................................................................................................................................2
Answer 2:...................................................................................................................................3
2.1 Signs and symptoms of Tuberculosis (TB):.....................................................................3
2.2 Disease Burden of Tuberculosis:.....................................................................................4
Answer 3:...................................................................................................................................5
3.1 Contact Tracing-...............................................................................................................5
3.2 Steps of contact tracing:...................................................................................................5
Answer 4:...................................................................................................................................8
4.1 General Information on TB:.............................................................................................8
4.2 Infectiousness and Risk Factors of Tuberculosis:............................................................9
4.3 High Risk groups:..........................................................................................................10
4.4 Procedures for Household contacts:...............................................................................10
4.5 Rest period and chances of re infection:........................................................................11
Answer 5:.................................................................................................................................11
Guidelines for the control of Tuberculosis in Northern Territory and Victoria:..................11
References:...............................................................................................................................13

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Answer 1:
A Notifiable disease can be any disease that has a legal obligation to be reported to
the government/ public health authorities, when it is diagnosed since the disease can be
potentially harmful to health (Gibnet et al., 2016). It is also known as “reportable disease”.
Collected reports of this disease can allow its monitoring, and provide an early warning if an
outbreak is imminent. Several governments have laws being enacted and enforced that
stipulates reporting of diseases in both Humans and Animals (or livestocks). Some of the
notifiable diseases (caused by bacteria and viruses) in Australia are: Anthrax, Botulism,
Brucellosis, Cholera, Diphtheria, Leprosy, Leptospirosis, Pertussis, Plague, Salmonellosis,
Shigellosis, Syphillis, Tetanus, Tuberculosis, Typhoid fever, AIDS, Arbovirus infections,
Hepatitis, (A-E), HIV, Influenza, Measles, Poliomyelitis, Rubella, Small Pox and Yellow
Fever. Other disease includes: Amoebic Dysentery, Cancer, Dysentr, Malaria, Giardiasis and
Trichinosis, to name a few (Gibney et al., 2017).
List of Australian websites that acts as repositories for information related to Notifiable
disease:
1. Department of Health, Australia (http://www.health.gov.au/casedefinitions)
2. Department of Agriculture, Australia (http://www.agriculture.gov.au/pests-diseases-
weeds/animal/notifiable)
3. Database of notificable diseases, Australia (https://data.gov.au/dataset/national-
notifiable-diseases-surveillance-system)
4. Department of Health, Australia (http://ww2.health.wa.gov.au/Silver-book/STI-or-
HIV-notification/Australian-national-notifiable-disease-case-definitions)
5. Government of South Australia
(

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http://www.sahealth.sa.gov.au/wps/wcm/connect/public+content/sa+health+internet/
clinical+resources/health+notifications/notifiable+disease+reporting)
6. Northern Territory Government (https://health.nt.gov.au/professionals/centre-for-
disease-control/cdc-programs-and-units/notifiable-diseases)
7. Federal Register of Legislation, Australian Government
(https://www.legislation.gov.au/Details/F2008L00800)
8. Department of Agriculture and Fisheries, Australia
(https://www.daf.qld.gov.au/animal-industries/animal-health-and-diseases/notifiable)
9. Livestock Biosecurity Network, Australia
(http://www.lbn.org.au/farm-biosecurity/notifiable-diseases/)
Answer 2:
2.1 Signs and symptoms of Tuberculosis (TB):
Tuberculosis is a bacterial disease which can be fatal if not treated properly (Fogel,
2015). The bacterium (Mycobacterium tuberculosis) spreads via tine droplets released while
coughing or sneezing, and affects the lungs. However tuberculosis infection can exist in a
Latent or Active state. In the Latent stage, the bacteria remain in the body in an inactive and
non-contagious stage, and exhibit no symptoms. However, the latent bacterium can become
active in the body, causing the onset of symptoms (Getahun et al., 2015). In the Active stage,
the bacterium is infective and can spread from person to person. The typical signs and
symptoms at this stage includes: Cough that lasts for more than three weeks, discharge of
blood during cough, pain in the chest and difficulty in breathing, weight loss, fatigue,
fever, nocturnal sweats, chills and appetite loss. Symptoms of primary pulmonary
tuberculosis include fever or dry cough, and are often temporary. People suffering from
pulmonary disease from Tuberculosis can develop Tuberculosis Pleuritis. The pleural

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disease can occur when the diseased area ruptures into the space between the lining of
abdominal cavities, chest and lungs, causing chest pains (Khan et al., 2013). The TB
bacterium can also spread to different parts of body via blood, in immune-compromised
patients, causing military tuberculosis (symptoms: fever, weakness, appetite and weight loss,
cough and difficulty breathing). Infections of the upper respiratory system causes symptoms
like frequent coughs, with a progressively increasing amount of mucous produced, coughing
of blood, fever, loss of appetite and weight, and nocturnal sweats. In rare cases, the bacterium
can also develop in other organs like Lymph Nodes, Bones and Joints, Genitourinary tract,
Meninges and the lining of GI tract.
2.2 Disease Burden of Tuberculosis:
Studies from 2012 and 2013 shows the rate of TB occurrence in Australian born
population at 0.9 to 1.0 per 100,000 individuals. Indigenous Australians have shown to
experience a greater burden (4.5 to 4.6 per 100,000 individuals) of the disease, compared to
Non Indigenous Australians (0.7 to 0.8 per 100,000), showing an incidence that is six times
higher. Compared to to other countries, the disease burden of Tuberculosis in Australia is low
(that is, less than 10 reported cases per 100,000) along with Western Europe, USA, Canada
and New Zealand (http://www.who.int, 2017). Data collected by National Notifiable Disease
Surveillance System showed 1317 reported cases as of 2012 and 1263 as of 2013 (rate of 5.8
to 5.2 per 100,000). The overseas-born Australians however showed a much higher incidence
of TB at 19.5 to 18.4 per 100,000 cases. Multi Drug resistant TB also shows a lower
prevalence in Australia at 20 cases reported as of 2012 and 22 as of 2013, most of which
were reported in the overseas born Australians. Also, the disease burden of TB tends to be
higher among children than healthy adults (Seddon & Shingadia, 2014). Overall, Australia
shows an excellent and sustained control of TB, and proves its commitment to alleviate the
global burden of this disease.

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Answer 3:
3.1 Contact Tracing-
In the context of epidemiology, Contact Tracing refers to the process of identification
follow up and diagnosis of individuals who came in contact with the infected individual(s)
(Begun et al., 2013). This is a useful means of controlling infectious disease (like TB, HIV
and STD’s) and their epidemiologic investigation and surveillance (Sabat et al., 2013). The
purpose of contact tracing is to detect the early symptoms in the contacts, monitor and treat
them for disease. It can help in secondary prevention (preventing disease in the individuals
exposed to it) tertiary prevention (preventing severe outcomes) and prevent or contain
outbreaks. Contact tracing is done when mode of contact is direct contact (casual or sexual).
A pre-test tracing of contact is needed when there is high level of concern for the patient, and
waiting for the laboratory reports can be detrimental. A post test tracing of contact is done
after diagnosis have been confirmed, and can reduce adverse effects to the exposed contacts.
3.2 Steps of contact tracing:
Step 1: Clarifying the reasons to trace contacts- The patients needs to be made
aware of asymptomatic infection, possible complications if not tested, risk of infection. This
can ensure proper participation from the infected, and uphold the basic human rights. While
clarifying the reasons, information must also be justified with currently known knowledge,
keeping the individuals up to date.
Step 2: Help to identify who’s who needs notifications of the disease- The mode of
transmission, and the duration of infective stage needs to be discussed. Tracing back of
contacts since the relevant time period. This will allow understanding the extent of the
spread, and finding ways to control it. Also, depending upon the proximity to those contacts,
a proper method to communicate with them must also be devised. The mode of transmission

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can allow understanding how the infection spreads through the population, so that the risks
can be managed. Once the possible infection cases are identified they can be screened to
check if they are test positive for TB.
Step 3: Explanation of the methods involved and offering choice- Notification of
patients can be done by patient or provider referral. Working with patients to identify
appropriate methods applicable to each of the listed contacts. Patient referral involves
personal notification by the index patient to his/her contacts. Provider referral involves the
healthcare providers advising the patient directly or through an agency. Referring the patients
can allow the screening of these contacts for exposure and infection. It can also check if any
further infection was spread by those individuals.
Step 4: Support to the patient, and providing patient referral for future contact.
Since the patient undergoing screening and treatment requires medical expertise, and
improper treatment can lead to complications or re exposure, it is important to educate the
contacts about the right procedures, and provide support to them when needed
(http://www.health.gov.au, 2017).
Identification of contacts allows identifying the initial case, identifying additional
incidents among individuals in contact with the initial case, identifying individuals who
might be infected due to contact with the initial case, providing counseling and assessment to
those diagnosed with TB. Categorization of the case is needed as per the degree of
infectiousness. Also categorization of contacts depending upon the risk of exposure allows
identifying the high risk cases. Examination of medium risk cases should follow next if there
is any evidence of transmission. Investigation of contacts requires noting down of the
history, performing IGRA and/or TST or radiographic investigation when indicated
(Balmelli, 2014). All the contacts tested positive for TST or IGRA needs to be referred to

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healthcare practitioners involved in diagnosis and treatment of TB, and treatment for LTBI
should be considered. Young children with a history of immuno-supression and TST below 5
should be referred for TB diagnosis and treatment. Children below 5 years in household
contact with individuals tested smear positive should be evaluated for infection. In special
cases like in exposure inside Aircraft, schools, hospitals or healthcare centers, or during
pregnancy, factors like the infectiousness of the initial or index case should be analyzed. Also
the duration of exposure (like the travel time in aircraft, or school hours, or the time admitted
in hospital where the infection occurred must be noted).
Susceptibility of those who might have been infected must also be taken into
consideration. A list of possible consequences that might ensue, must be made and shared
with the concerned individuals. Any delay between the infection and screening should be
taken into account, as with increased delays, the chances of further exposure also increases.
In Australia, contact racing needs to adhere to section 71 of Public Health Act 1991.
The sensitivity and circumstances that dictates contact tracing, as well as its scope must be
clarified. Advice must also be sought from NSW Department of Health. Next the degree of
infectiousness must be noted, based on clinical, bacteriological, radiological and nucleic acid
tests. The degrees of infectiousness can be categorized as High Infectiousness (positive for
sputum smear/ laryngeal involvement/ x ray of chest/ evidence of transmission to others),
Medium Infectiousness (smear negative but positive for sputum culture or nucleic acid test,
pleural disease, positive smear for bronchial wash) and Low Infectiousness (negative for
sputum smear and culture).
Determination of the infective period is important to identify the high risk groups
for tracing. The infective period needs to be considered 3 months prior to the TB diagnosis,
unless a clear set date of the onset exists. Assigning priority can be done based on naming

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risk groups (high risk, medium risk and low risk). High Risk groups would be those who
have had regular and long contacts inside a closed environment during the infective period,
and can include individuals in the same household, close relatives, friends, colleagues who
are working closely in a small work area (Gao et al., 2016). Medium Risk groups would be
those who would have frequent but lesser time spent with the infected and can include
relatives, friends, schoolmates, colleagues, neighbors who are not in high risk group. Low
Risk group would be the other contacts in workplace or school or other places that are not in
High or Medium Risk groups.
Risk groups for Tuberculosis also need to be identified. The chances of TB
progressing from latent to infective stage is considerably higher in children who are below 5
years, who are suffering with HIV; people receiving 15mg or more of prednisone (or
equivalent) for four or more weeks; people on immunosuppressive medication; people
suffering from cancer/ diabetes mellitus/ silicosis/ and kidney failure; and people who
underwent jejunoileal surgery or gastrectomy. The high risk contacts are to be screened the
first.
Answer 4:
4.1 General Information on TB:
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. The bacterium
generally invades the lungs, but is also capable of infecting other organs. In its latent form,
TB shows no symptoms, but has a 10% chance of progressing to active or infective form. The
most common symptoms include chronic cough, sputum with blood, night sweats and
fevers accompanied by loss of weight. The disease spreads via air (by sputum droplets
discharged due to cough, sneeze or while speaking) from individuals who have infective
stage of the bacterium in their lungs.

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According to WHO report on Tuberculosis in 2016, a total of 1376 cases (new and
relapse) were reported in Australia. The rate of mortality from TB+ HIV were reported at
0.02 (per 100,000), and incidence of TB+HIV at 0.12 (per 100,000). Overall the disease
burden of TB is Australia is very low, with the highest reported cases found among Overseas
born or Non residential Australians.
4.2 Infectiousness and Risk Factors of Tuberculosis:
Tiny aerosol droplets (0.5 to 5.0 microns) up to 40,000 in number can be discharged
while coughing or sneezing. With a small dose of infection (less than 10 bacterium to fully
develop the disease), each of the infective droplet can potentially cause or spread the disease.
People in constant contact with the infected are at a high risk of developing TB symptoms
(Fox et al., 2013). An infected person can potentially spread the disease to an average of 10-
15 people or more in a year. Transmission occurs only from only those people who have
active TB, and the latent form is not contagious. The chances of the spread of infection
depends upon several factors, like the number of infective droplets released, the
ventilation condition inside the place where the droplets were released in the air, the length
of exposure, the level of virulence of the bacterium (drug resistant/ multi drug resistant) and
the immune condition of the individuals exposed.
Risk Factors: People suffering with HIV are at the highest risk globally (Sester et al.,
2014). Also, the disease is related closely in overcrowded places, especially when people are
suffering from malnutrition, thereby making it a “disease of poverty”. Other risk factors
includes people involved in drug abuse, those in contact with or working the infected
individuals, economically poor or underprivileged societies, children who are exposed to
the pathogen, ethnic minorities, healthcare professionals involved in TB treatment and
management (Narasimhan et al., 2013). Chronic lung disease can also increase the chances
on TB infection along with Silicosis and tobacco smoking. Certain diseases like diabetes

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mellitus can also be a risk factor for TB. In addition genetic susceptibility, medications like
corticosteroids and alcoholism can increase the prevalence of the disease.
4.3 High Risk groups:
The high risk groups of contact tracing includes those who have had regular and
long contacts inside a closed environment during the infective period, like individuals in the
same household, close relatives, friends, colleagues who are working closely in a small work
area. Foreign nationals who have emigrated from a country with high disease burden of TB
in the last 5 years. Residents living in high risk settings (prisons, homeless shelters, nursing
home, rehabilitation centers, healthcare centers). Healthcare professionals who are treating
infected individuals. Low income groups or other groups who might be under serviced
medically and high risk ethnic minorities. Children or infants or adolescents exposed to the
disease. Also the risk of the disease progressing from the infective to non infective stage is
higher in people with HIV infection, people already infected with TB in the last 2 years
(specially infants or young children), people with existing medical conditions, people who
were improperly treated for TB previously, and drug users (van Hest & de Vries, 2016).
4.4 Procedures for Household contacts:
The Household contacts are at a high risk of developing the disease. Those exposed to
highly infectious case needs to be screened in the span of 7 days from diagnosis. Those
exposed to low or medium infective cases be screened by 2 weeks from diagnosis. Tracing of
TB cases which are extra pulmonary can be done to identify the source or initial case.
Contact screening should also be done when the infection is thought to be transmitted in the
past. On the first visit, a clinical history needs to be recorded to clarify the risk of exposure,
record the vaccination status for BCG, identifying symptoms related to TB, identifying any
pre existing medical condition that can increase the risk of the disease, and identifying
situations that can interfere with the result of TST.

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In the current scenario, the following measures are needed to screen contacts of the
source case: The family members by screened for TB. Their BCG vaccination status and
reported symptoms be noted. Any pre existing medical condition is noted.
4.5 Rest period and chances of re infection:
The patient would need a resting period of 6 months, during which he will have
minimal contacts with the outside world, preferably in a private room, with sufficient
ventilation. The isolation needs to be continued as long as 3 consecutively negative results
occur in sputum smear test. During the resting period, contacts of the index case will still be
at high risk, and therefore would have to undergo regular screening for the infection. Once
the disease is successfully cured from the index case, there will be no chances of re infection.
Therefore teachers and parents need not worry about being reinfected, once the recommended
treatment procedure has been complied with (Horsburgh, Barry & Lange, 2015).
Answer 5:
Guidelines for the control of Tuberculosis in Northern Territory and Victoria:
The jurisdiction of Northern Territory comprises of Disease Control units in Darwin,
Tennant Creek, Alice Springs and Nhulunby. The jurisdiction of Victoria is in the state of
Victoria. In the Northern Territory jurisdiction, the cases are first categorized based on
infectiousness. After this a list of contacts are obtained from the infected patients and
arranged according to their risks. The high risk contacts are next identified, followed by
medium and low risk individuals. If the case diagnosis is from an indigenous community, the
treating staff needs to travel to such areas and help to educate the community, and assist
contacts whenever necessary (http://digitallibrary.health.nt.gov.au, 2017).

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In the Victoria Jurisdiction, public nurses from The Victorian Tuberculosis Program
are responsible for both contact tracing and investigation. The practices follow the protocols
set by the Communicable Diseases Network of Australia (CDNA) via a series of National
Guidelines, and are endorsed by AHPPC (Australian Health Protection Principal Committee
(2013). The index case is identified by clinical presentations, symptom duration, disease site,
bacteriological report and radiological report. Once the index case is identified, the high risk
contacts are then identified, followed by medium and low risk contacts. The contacts have to
then undergo clinical evaluation, tuberculin skin test (TST) or Interferon Gamma Release
Assay (IGRA). The TST also needs to be repeated after 8-12 weeks. A chest X ray is done
next, followed by contact follow-ups and any special categories also need to be identified
(www.thermh.org.au, 2017).
So, it can be seen that the northern territory employs an additional role of educating
indigenous communities who are at high risk of TB, and providing support to them in their
treatment.

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References:
Balmelli, C., Zysset, F., Pagnamenta, A., Francioli, P., Lazor-Blanchet, C., Zanetti, G., &
Zellweger, J. P. (2014). Contact tracing investigation after professional exposure to
tuberculosis in a Swiss hospital using both tuberculin skin test and IGRA. Swiss
medical weekly, 144, w13988-w13988.
Begun, M., Newall, A. T., Marks, G. B., & Wood, J. G. (2013). Contact tracing of
tuberculosis: a systematic review of transmission modelling studies. PloS one, 8(9),
e72470.
Dean, A., Zignol, M., & Mecatti, F. (2015). Guidelines for surveillance of drug resistance in
tuberculosis. World Health Organization WHO Press.
Fogel, N. (2015). Tuberculosis: a disease without boundaries. Tuberculosis, 95(5), 527-531.
Fox, G. J., Barry, S. E., Britton, W. J., & Marks, G. B. (2013). Contact investigation for
tuberculosis: a systematic review and meta-analysis. European Respiratory
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Gao, L., Bai, L., Liu, J., Lu, W., Wang, X., Li, X., ... & Jin, Q. (2016). Identification of
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tuberculosis infection. New England Journal of Medicine, 372(22), 2127-2135.
Gibney, K. B., Cheng, A. C., Hall, R., & Leder, K. (2016). An overview of the epidemiology
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Infection, 144(15), 3263-3277.

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Gibney, K. B., Cheng, A. C., Hall, R., & Leder, K. (2017). Sociodemographic and
geographical inequalities in notifiable infectious diseases in Australia: a retrospective
analysis of 21 years of national disease surveillance data. The Lancet Infectious
Diseases, 17(1), 86-97.
Horsburgh Jr, C. R., Barry III, C. E., & Lange, C. (2015). Treatment of tuberculosis. New
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