Download Disease/Public Health PPT

Public Health and Disease
Notes
Terms Relating to Disease
• Public health – the patient is the population
• Epidemiology - the study of the incidence, distribution
and determinants of an infection, disease or other
health-related event in a population. Epidemiology
can be thought of in terms of who, where, when, what,
and why.
• That is, who has the infection/disease, where are they
located geographically and in relation to each other,
when is the infection/disease occurring, what is the
cause, and why did it occur.
Terms Relating to Disease
Endemic – prevalent and permanent in
or restricted to a particular locality, ex.
malaria in the tropics
Epidemic – “outbreak” or spread of a
disease among people in a specific
community
Pandemic – global disease outbreak;
determined by how the disease
spreads, not by the number of deaths
Terms Relating to Disease
Chronic - of long duration, denoting a
disease of slow progress, typically noncommunicable
Ex: cancer, kidney disease, diabetes
Acute – lasts for just a short time, but can
begin rapidly and have intense symptoms
Ex: colds, influenza, respiratory infections
Infectious – caused by infection or capable
of causing infection
Terms Relating to Disease
Immunization/Vaccination - the act of inducing antibody formation
leading to immunity.
Vaccines - A preparation made from killed or weakened pathogens
which when introduced in the body induce the production of
antibodies and thus boost the body's immunity against that pathogen.
Pathogen - A microbe, such as virus or bacteria, which may cause
disease.
Vector - An agent, usually an animal or an insect, that transmits a
pathogen from one host to another. Ex. mosquitoes transmit the
plasmodium that causes malaria
Transmission – spreading of a communicable disease from an
infected host to another person; Various ways -- droplet infection,
direct physical contact, indirect physical contact, airborne, fecal-oral
Major Diseases
• Re-emerging
Diseases
- Tuberculosis
- Cholera
- Influenza
- Malaria
*Smallpox eradicated in
1980
•
New diseases
- HIV
- Hepatitis
- Ebola
- Avian Flu
- SARS
Tuberculosis
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TB is second only to HIV/AIDS as the greatest killer worldwide due to a
single infectious agent
According the World Health Organization, in 2013, 9 million people fell ill
with TB and 1.5 million died from the disease. Over 95% of TB deaths occur
in low- and middle-income countries.
TB is a leading killer of people living with HIV causing ¼ of all deaths
About 1/3 of the world's population has latent TB, which means people have
been infected by TB bacteria but are not (yet) ill with disease and cannot
transmit the disease. People infected with TB bacteria have a lifetime risk of
falling ill with TB of 10%. However persons with compromised immune
systems, such as people living with HIV, malnutrition or diabetes, or people
who use tobacco, have a much higher risk of falling ill.
Spreads via ill persons through air and casual contact
Multi-drug resistant TB (MDR-TB) is present in all countries surveyed by the
WHO.
TB is curable and preventable
DOTS (Direct Observation Treatment Short Course).
The TB death rate dropped 45% between 1990 and 2013.
Malaria
• There were about 198 million cases of malaria in 2013 and an
estimated 584 000 deaths
• Most deaths occur among children living in Africa where a child dies
every minute from malaria
• world’s worst tropical and subtropical disease
• vector-borne disease – caused by plasmodium parasites that are
transmitted to people through the bites of infected mosquitoes.
• Increased malaria prevention and control measures are dramatically
reducing the malaria burden in many places
• Malaria is preventable and curable
• Some effective drugs; mosquito nets and repellent offer protection,
search for effective vaccine
• Parasites are developing drug resistance
• Malaria mortality rates have fallen by 47% globally since 2000, and
by 54% in the WHO African Region.
• However, in Africa a child dies every minute from malaria
Cholera/Diarrheal Diseases
• Researchers have estimated that there are 1.4 to 4.3 million cases,
and 28,000 to 142,000 deaths worldwide due to cholera every year,
mostly in lesser developed countries.
• Among people who develop symptoms, 80% have mild or moderate
symptoms, while around 20% develop acute watery diarrhea with
severe dehydration. This can lead to death if left untreated. Again,
particularly dangerous for children
• caused by ingestion of food or water contaminated with the
bacterium Vibrio cholerae.
• Outbreaks are typically caused by a contaminated water supply
• Easily treatable with oral rehydration salts
• Provision of safe water and sanitation are critical to control
outbreaks
Cholera cont.
• Cholera transmission is closely linked to inadequate environmental
management. Typical at-risk areas include urban slums, where
basic infrastructure is not available, as well as camps for internally
displaced people or refugees, where minimum requirements of clean
water and sanitation are not met.
• The consequences of a disaster – such as disruption of water and
sanitation systems, or the displacement of populations to inadequate
and overcrowded camps – can increase the risk of cholera
transmission should the bacteria be present or introduced. Haiti
after earthquake of 2010 – 350,000 cases and 5,400 deaths
• During the 19th century, cholera spread across the world from its
original reservoir in the Ganges delta in India. Six subsequent
pandemics killed millions of people across all continents. The
current (seventh) pandemic started in South Asia in 1961, and
reached Africa in 1971 and the Americas in 1991. Cholera is now
endemic in many countries.
Influenza
• acute viral infection that spreads easily from person to person and
circulates worldwide and can affect anybody in any age group.
• causes annual epidemics that peak during winter in temperate
regions.
• An epidemic can take an economic toll through lost workforce
productivity, and strain health services.
• Seasonal flu - mutations (antigenic drift) occur almost yearly,
vaccinations are needed
• Pandemic flu – mutations (antigenic shift) occur when two different
flu strains combine and it can be disastrous. Ex. -“Spanish flu” of
1918-1919 killed more people than all of WWI, killed 50-100 million
people, most deadly pandemic the world has ever seen. Killed 2.5%
of world population. Evidence now shows that the “Spanish Flu” was
a strain of Avian Flu (bird flu)
• Came and went within 18 months
• Contemporary strains are less dangerous, but when recombined
with bird flu strains they could be.
HIV/AIDS
Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome
• HIV continues to be a major global public health issue, having
claimed more than 34 million lives so far. In 2014, 1.2 [1.0–1.5]
million people died from HIV-related causes globally.
• There were approximately 36.9 [34.3–41.4] million people living with
HIV at the end of 2014 with 2.0 [1.9–2.2] million people becoming
newly infected with HIV in 2014 globally.
• Sub-Saharan Africa is the most affected region, with 25.8 [24.0–
28.7] million people living with HIV in 2014. Also sub-Saharan Africa
accounts for almost 70% of the global total of new HIV infections.
HIV/AIDS
• A cure for HIV infection has not been found but with effective
treatment with antiretroviral (ART) drugs, patients can control the
virus and enjoy healthy and productive lives.
• In 2014, 14.9 million people living with HIV were receiving
antiretroviral therapy (ART) globally, of which 13.5 million were
receiving ART in low- and middle-income countries. The 14.9 million
people on ART represent 40% [37–45%] of people living with HIV
globally
• Sub Saharan Africa – 71% of infection and 76% of deaths; 61% of
infected are women; 14 million orphans
• Refer to articles for causes and effects, treatments, cultural, and
social issues