An academic assignment on Control and Prevention of Diseases Prepared by Dr.Md.Muniruzzaman DVM,VPHFH,HSTU,Dinajpur-5200

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Control and Prevention of Diseases
The survival of the fittest'(Charles Darwin). In the world every individual fight against others
and his surrounds to survive. The most common war for living individuals is fight against
diseases. There are sever causes of disease and all can be categorized as Infectious and
noninfectious diseases. Among them infectious diseases are a leading cause of illness and death
throughout the world. The enormous diversity of microbes combined with their ability to
evolve and adapt to changing populations, environments, practices, and technologies creates
ongoing threats to health and continually challenges
our ability to prevent and control disease. In low‐
income countries, the impact of infectious diseases is
often devastating— decreasing survival rates,
particularly among children, and impeding
opportunities for economic growth and
development. In more developed countries,
infectious diseases also continue to present significant
health and economic concerns. However, every
disease has certain weak points susceptible to attack.
The basic approach in controlling and prevention
disease is to identify these weak points and break the
weakest links in the chain of transmission.
Definitions:
Diseases: A disease is any condition which results in the disorder of a structure or function in
a living organism that is not due to any external injury. The study of disease is called pathology,
which includes the study of cause. Disease is often construed as a medical condition associated
with specific symptoms and signs.
Control: Disease incidence is reduced to a minimal level, acceptable at the level of
country/region, at which the disease is no longer considered a public health problem, while
infection may still occur.
Prevention: Activities designed to protect patients and other members of the public from actual
or potential health threats and their harmful Consequences-(Mosby s Medical Dictionary, 8th
edition.2009)
Disease prevention covers measures not only to prevent the occurrence of disease, such as risk
factor reduction, but also to arrest its progress and reduce its consequences once established
(WHO, Geneva, 1984)
Elimination: Reduction to zero of the incidence of a specified disease in a defined community
or country or region as a result public health actions.
Eradication: Termination of all transmission of infections by extermination of infectious
agents.

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Control of Diseases:
Controlling Diseases at Health Worker Levels:
Physician, veterinarian, nurses, public health practitioners and others which are directly
involved in health services should practice the following points to protect them and control of
diseases transmission by aseptic technique which is a key component of all invasive medical
procedures.
Infection control in healthcare facilities: A hospital or healthcare facilities center-associated
infection prevention manual containing instructions and practices for patient care is an important tool.
The manual should be developed and updated by the infection control team and reviewed and
approved by the committee. It must be made readily available for health care workers and updated in
a timely fashion.
Hand hygiene: Hand hygiene is now regarded as one of the most important elements of
infection control activities. In the wake of the growing burden of health care associated
infections (HCAIs), the increasing severity of illness and complexity of treatment,
superimposed by multi-drug resistant (MDR) pathogen infections, health care practitioners
(HCPs) are reversing back to the basics of infection preventions by simple measures like hand
hygiene. This is because enough scientific evidence supports the observation that if properly
implemented, hand hygiene alone can significantly reduce the risk of cross-transmission of
infection in healthcare facilities (HCFs)
Sterilization: Sterilization is the killing or removal of all microorganisms, including bacterial
spores which are highly resistant from all usable equipment.
Cleaning: To removing unwanted substances, such as dirt, infectious agents, and other
impurities, from an object or environment.
Disinfection: Use of a disinfectant to destroy, inactivate or remove microorganisms that are
likely to cause infection, spoilage or other undesirable effects in an inanimate object.
Personal protective equipment: Employers have duties concerning the provision and use of
personal protective equipment (PPE) at work. PPE is equipment that will protect the user
against health or safety risks at work. It can include items such as safety helmets, gloves, eye
protection, high-visibility clothing, safety footwear and safety harnesses. It also includes
respiratory protective equipment (RPE)
Antimicrobial surfaces: An antimicrobial surface contains an antimicrobial agent that inhibits
the ability of microorganisms to grow on the surface of a material. Such surfaces are becoming
more widely investigated for possible use in various settings including clinics, industry, and
even the home.
Vaccination of health care workers: Vaccination for immunization.
Surveillance for infections: Surveillance is an essential component of an effective infection
prevention and control program– Sound epidemiological and statistical principles– Use
surveillance data to improve the quality of healthcare.

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Control of Route of Transmission:
Isolation and quarantine:
Isolation has a distinctive value in the control of some infectious diseases, e. g., diphtheria,
cholera, streptococcal respiratory disease, pneumonic plague, etc. In some diseases where there
is a large component of subclinical infection and carrier state (polio, hepatitis A, and typhoid
fever), even the most rigid isolation will not prevent the spread of the disease. It is also futile
to impose isolation if the disease is highly infectious before it is diagnosed as in the case of
mumps. Isolation has tailed in the control of diseases such as leprosy, tuberculosis. In the
control of these diseases, the concept of physical isolation has been replaced by chemical
isolation, i.e., rapid treatment of cases in their own homes and rendering them non-infectious
as quickly as possible. Lastly, cases are usually reported after the disease has spread widely
Taking all these limitations into consideration, it may be stated that isolation which is a "barrier
approach" to the prevention and control of infectious disease is not as successful as one would
imagine and may well give rise to a false sense of security. In modern-day disease control,
isolation is more judiciously applied and, in most cases, replaced by surveillance because of
improvements in epidemiological and disease control technologies. Today isolation is
recommended only when the risk of transmission of the infection is exceptionally serious
Quarantine has been defined as "the limitation of freedom of movement of such well persons
or domestic animals exposed to communicable disease for a period of time not longer than the
longest usual incubation period of the disease, in such manner as to prevent effective contact
with those not so exposed “. Quarantine measures are also "applied by a health authority to a
Route Example Control Measures
Direct contact Kissing, sexual contact, skin-to-skin
contact
Use of barrier (condom,
clothing, dressing)
Droplet Organism on large respiratory
droplets that people sneeze, cough,
drip, or exhale.
Respiratory etiquette
Indirect contact Contact with contaminated surfaces,
clothing, etc.
Hand-hygiene, sanitizing
infected surfaces
Vector Bite from disease-carrying ticks,
fleas, mosquitoes
Vector control
Vehicle Eat/drink contaminated food/drink,
transfuse infected blood, fomites
(bedding, infected tattoo needle)
Proper hygiene and sanitation,
cook food/boil water, etc.
Airborne Organism on dust particles or
small respiratory droplets
Respiratory etiquette,
isolation (if necessary)

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ship, an aircraft, a train, road vehicle, other means of transport or container, to prevent the
spread of disease, reservoirs of disease or vectors of disease"
Epidemiological Investigations:
An epidemiological investigation is called for whenever there is a disease outbreak the
methodology for which is given elsewhere. Broadly, the investigation covers the identification
of the source of infection and of the factors influencing its spread in the community. These may
include geographical situation, climatic condition, social, cultural and behavioral patterns, and
more importantly the character of the agent, reservoir the vectors and vehicles, and the
susceptible host populations.
Training in infection control and health care epidemiology: Health administrators should be
oriented towards the importance of the infection control programme. Health care workers should be
equipped with requisite knowledge, skills and attitudes for good infection control practices.
Controlling Diseases at Their Animal Source
National Veterinary Services are at the very core of the system for the prevention and control
of animal diseases. Among other aspects, they are responsible for early detection and rapid
response to outbreaks of emerging or re-emerging animal diseases. Enhancing the governance
of Veterinary Services must be the focus worldwide, aimed at optimizing the quality and
effectiveness of disease prevention and control systems, based on suitably adapted legislation.
The Veterinary Services in developing and in-transition countries require suitably adapted
legislation and the human and financial resources to enforce it, as well as capacity-building, in
order to protect animal health and thus public health, including food security and food safety.
Effective Surveillance: Upstream of animal disease prevention and control activities, there
must be effective active (planned) or passive (event-based) surveillance. The OIE defines
surveillance as ‘The systematic ongoing collection, collation, and analysis of data, and the
timely dissemination of information to those who need to know so that action can be taken.’
(OIE Terrestrial animal Health Code). To be effective, this strategy requires optimal
communication and collaboration between all stakeholders at all levels of the animal
production chain, from the animal producer, her/his veterinarian and the local laboratory, to
the highest national veterinary authorities
Early Detection of Diseases: An early detection system enables the timely detection and
identification of an incursion or emergence/re-emergence of a disease/infection in a given
country, zone or compartment. It must be under the official control of the Veterinary Services
complying with relevant OIE standards and includes the following characteristics: –
representative coverage of target animal populations, by fled services throughout the territory
in good cooperation with farmers and stakeholders;– ability to undertake effective
epidemiological investigations and reporting; – access to laboratories capable of diagnosing
and differentiating relevant diseases; – a training programme for veterinarians, veterinary para-
professionals and other stakeholders for detecting and reporting animal health incidents; – the
legal obligation for private veterinarians to report to the national Veterinary Authority; – a
well-established national chain of command.

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a) Collecting Samples: In order to have a rapid and effective diagnosis of any new disease
occurrence, the veterinary authorities must have a response mechanism for sample
collection and laboratory analysis. Particularly in developing countries, the shortage of
Feld veterinarians often means that disease detection and sample collection operations
have to be entrusted to suitably trained farmers or para professionals under close
supervision of accredited veterinarians.
b) Diagnosis: Once aware of a disease outbreak, the veterinary authorities must ensure
that the national and international community is well alerted, and that a final
confirmation and characterization of the pathogen be determined, if necessary in an
OIE Reference Laboratory for the specified disease. OIE has a global network of 296
Reference Laboratories and Collaborating Centers covering all relevant animal
diseases. (See Cartography).
Notification of Animal Diseases to the OIE: The OIE ensures the transparency of the world
animal health situation. On becoming an OIE Member, each country undertakes to report the
terrestrial and aquatic animal health situation in its territory in a timely and transparent manner.
The 180 OIE Member Countries can connect to the OIE server at any time to fulfil their
obligation to provide information, in a timely manner, on any relevant domestic or wild animal
disease detected within their territory.
Rapid Response Mechanisms:
Biosecurity: Biosecurity policies and measures taken to protect human and animal health from
biological risks are essential. In the case of a disease outbreak in a non-endemic area,
depopulation (by humane killing of infected and in-contact animals, in accordance with OIE
standards), followed by disinfection of establishments, equipment and vehicles, in conjunction
with a temporary ban or control of movements animals, will often be sufficient to prevent the
spread of the pathogen. Appropriate biosecurity measures must be implemented throughout the
world. Member Countries must comply with OIE standards and guidelines, by ensuring that all
those involved are properly trained and by providing them with the necessary material and
human resources.
Vaccination: Vaccination is very useful in the prevention and control of many diseases, if it
conforms to an existing disease control programme. However, vaccination on its own will not
usually achieve the desired results unless the vaccination programme is part of an integrated
control strategy utilizing a combination of control measures.
Implementing a vaccination strategy If it is determined that vaccination is an option, before
launching a specific vaccination policy Member Countries need to make sure that the
preconditions for a successful outcome have been met, i.e. ensuring vaccine quality and
defining the conditions under which any vaccination policy must eventually be stopped (exit
strategy).
Vaccine quality Vaccines should be produced in accordance with international guidelines
prescribed in the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. For
most vaccines, ensuring a permanent cold chain (constant temperature control) is critical to the
successful implementation of a vaccination campaign. In some developing regions the OIE has

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created regional vaccine banks for rabies, foot and mouth disease and paste des petits ruminants
to provide support for its Member Countries in case of an emergency situation.
Animal identification and traceability Animal identification and traceability are very useful
tools in the effective control of animal diseases. In case of outbreaks, such measures will make
it easier to identify animals and animal products potentially exposed to the pathogen and allow
them to be traced, so that the appropriate control measures can be implemented. The application
of animal identification and traceability should comply with OIE standards
Preventive Measures of Diseases:
Most diseases are preventable to a greater or lesser degree, the chief exceptions being the
idiopathic diseases, such as the inherited metabolic defects. In the case of those diseases
resulting from environmental exposures, prevention is a matter of eliminating, or sharply
reducing, the factors responsible in the environment. Because chemicals and other substances
and materials originate largely from human activities, prevention ought to be a simple matter
of the application of well-established principles of industrial hygiene. In practice, however, this
is often difficult to achieve.
The infectious diseases may be prevented in one of two general ways:
(1) by preventing contact, and therefore transmission of infection, between the susceptible host
and the source of infection and
(2) by rendering the host unsusceptible, either by selective breeding or by induction of an
effective artificial immunity. The nature of the specific preventive measures, and their efficacy,
varies from one disease to another.
The concept of prevention is best defined in terms of levels of prevention. Traditionally,
Primordial prevention:
➢ Prevention of emergence or development of risk factors in countries or population
groups in which they have not yet appeared.
➢ It consists of actions and measures that inhibit the emergence and establishment of
environmental, economic, social and behavioral conditions, cultural patterns of living
known to increase the risk of disease.
➢ Mainly associated with chronic diseases.
➢ Intervention – Individual and mass education.
➢ Has to start in childhood when health risk behavior begins.
➢ Examples of primordial prevention
➢ National programmers and policies on:
• Food and nutrition
• Against smoking and drugs
• To promote regular physical activity

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Primary prevention:
➢ Action taken prior to the onset of disease, which removes the possibility that a disease
will ever occur.
➢ Intervention – pre-pathogenesis stage of disease.
➢ Concept of positive health: an acceptable level of health that will enable every
individual to lead a socially and economically productive life.
➢ Approaches for primary prevention for chronic diseases (WHO)
A. Population (mass) strategy:
• Directed at whole population irrespective of individual risk levels
• Directed towards socio-economic, behavioral and lifestyle changes
B. High risk strategy: To individuals at special risk.
➢ Efforts directed toward protection against specific diseases.
➢ Interventions:
✓ Immunization
✓ Use of specific nutrients
✓ Chemoprophylaxis
✓ Protection against occupational hazards
✓ Protection against accidents
✓ Protection from carcinogens
✓ Avoidance of allergens etc.

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Secondary prevention:
➢ Action which halts the progress of the disease at its incipient stage and prevents
complications.
➢ Intervention – early pathogenesis stage.
➢ It is the domain of clinical medicine.
➢ Earlier diagnosed – better prognosis.
➢ Reduces morbidity and mortality.
➢ Effective in acute conditions.
Tertiary prevention:
➢ All measures available to reduce or
limit impairments and disabilities,
minimize suffering caused by existing
departures from good health and to
promote the patient’s adjustment to
irremediable conditions.
➢ Intervention – late pathogenesis stage.
➢ The combined and coordinated use of
medical, educational, social and
vocational measures for training and
retraining the individual to the highest
possible level of functional ability.
➢ Requires cooperation from different
sections of society.
Quaternary prevention:
➢ The action taken to identify patient at risk of over-medicalization, to protect him from
new medical invasion, and to suggest to him interventions, which are ethically
acceptable.
➢ Quaternary prevention is the set of health activities to mitigate or avoid the
consequences of unnecessary or excessive intervention of the health system.
➢ Quaternary prevention should take precedence over any alternative preventive,
diagnostic and therapeutic, as is the practice version primum non nocere.
➢ Intervention types: Healthcare professionals must be aware of the consequences of their
decisions and include quaternary prevention interventions in their daily clinical practice
with each patient.
➢ Do not mistake risk factor with disease.
➢ To avoid checkups or unnecessary exams.
➢ To avoid technical interventionism in healthcare.

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Fig: Levels of Prevention of Diseases
To develop effective intervention programs, we will need to get people to change high-risk
behavior. We will need for people to stop doing things they have done for years and they will
need to begin doing things they perhaps have never done before. And we in the field of health
promotion will need to develop much more effective ways of communicating with people in
the community. To do that, we will have to re-think the way we classify diseases, we will need
to understand better what people care about, and we will need to do more relevant research.
This will require a new way of funding such research and of training a new generation of people
working in the field of health promotion and disease prevention. To accomplish this
transformation, we will require governmental policies very different from those now in place.
That may be the biggest, and most difficult, challenge of all. These are very challenging issues.
But so is the problem we face. We will need to do our best. And we will need to begin soon.

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Understanding disease pathology is the first step towards formulating preventive measures.
Prevention can be achieved in any stage of disease. Primordial or primary prevention is most
effective and economical. Disease control is also a part of prevention which is achieved by
means of continuous monitoring and surveillance of disease.
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