HUMAN GEOGRAPHY -
DISEASE DILEMMAS
, TOPIC ONE - WHAT ARE THE GLOBAL PATTERNS OF DISEASE AND CAN FACTORS BE IDENTIFIED THAT DETERMINE THESE?
TOPIC ONE A - DISEASES CAN BE CLASSIFIED AND THEIR PATTERNS MAPPED. THE SPREAD OF DISEASES IS COMPLEX AND
INFLUENCED BY A NUMBER OF FACTORS
THE CLASSIFICATION OF DISEASES
INFECTIOUS AND NON INFECTIOUS
Infectious diseases:
A disease caused by pathogens such as bacteria, viruses, parasites, and fungi
Examples include HIV, chicken pox, influenza, tuberculosis, cholera, typhoid
Historically, infectious diseases have been the main cause of death. They remain important in the developing world.
Malaria, for example, killed 583,000 people worldwide in 2013 and most of these deaths were in the poorest countries.
This is because in developing countries, medical technologies including antibiotics and vaccination are not widely available
due to a lack of wealth. People may also be less educated on measures that should be taken to prevent transmission of
infectious diseases.
Non Infectious diseases:
A non communicable disease, not caused by pathogens. Age, gender, inherited genes, environment, lifestyle, and diet can
affect the risk
Example include cancer, diabetes, dementia
CONTAGIOUS AND NON CONTAGIOUS
Contagious diseases:
An infectious disease spread by direct or indirect contact between people
Examples include covid 19, tuberculosis, HIV, Measles, Ebola
Non contagious diseases:
A disease that is not spread by direct or indirect contact between people
Examples include cardiovascular disease, cancer, dementia, diabetes
COMMUNICABLE AND NON COMMUNICABLE
Communicable diseases:
An infectious disease that is transmissible between people through a variety of ways, including contact with blood and
bodily fluids, airborne inhalation, contact with specific animals, and contact with a contaminated surface
Examples include malaria, lyme disease, rabies, ebola, hepatitis
Non communicable diseases:
A disease that is not transmissible between people because it is non contagious and non infectious. Age, gender, inherited
genes, environment, lifestyle, and diet can affect risk
Examples include cancer, cardiovascular disease, chronic respiratory disease
Zoonotic diseases are infectious diseases such as rabies, plague, and psittacosis, which are transmitted from animals to
humans. Transmission is common: one estimate suggests that around 60% of infectious diseases are spread from animals
DEGENERATIVE AND LIFESTYLE
These are non communicable diseases
Degenerative diseases are one you get as you age (for example dementia)
Currently 60% of deaths worldwide are due to degenerative diseases, reflecting the ageing of global population
The rates of some lifestyle diseases are also increasing in some countries. As a country develops, lifestyle may become
more unhealthy (more meat consumption, more consumption of fast food, less manual labour jobs and more sedentary
ones, activities using technology are more sedentary), leading to lifestyle diseases
,DEATH RATE AND MORBIDITY
Health - a state of complete physical, mental, and social well being and not merely the absence of disease or infirmity
Endemic - In epidemiology, an infection is said to be endemic in a specific population or populated place when that
infection is constantly present
Epidemic - An epidemic is the rapid spread of disease to a large number of hosts in a given population within a short period
of time. For example, in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two
consecutive weeks is considered an epidemic.
Pandemic - A pandemic is an epidemic of an infectious disease that has spread across a large region, for instance multiple
continents or worldwide, affecting a substantial number of individuals.
Morbidity
Illness and the reporting of disease
In the UK 2001 census respondents were asked how well they felt and whether they had a limiting long term illness
Some diseases are so infectious that by law they must be reported (such as cholera)
- Prevalence rate = indicates how many people in a population have a particular condition any one time
- Incidence rate = shows how many people in a population develop a particular condition during a given period of
time
Incidence conveys information about the risk of contracting the disease, whereas prevalence indicates how widespread it is
Attack rate - the number of cases of a disease diagnosed in an area, divided by the total population, over the period of an
epidemic
Death rate
Crude death rate - the number of deaths per 1000 people per year
The criticism of the crude death rate is that it fails to take into account the average age of the population (a country with an
elderly population is bound to have a high death rate)
Standardised age death rates may be used instead as the population’s age is taken into account. One example of a
standardised death rate is infant mortality
Infant mortality - the number of deaths of children under the age of one expressed per 1000 live births per year
Case mortality - the number of people dying from a disease divided by the number of those diagnosed as having the
disease
Mortality - the death of people. It is measured by a number of indices including death rate, infant mortality, case mortality,
and attack rate
Crude death rate is also not a good indicator of development. This is because a highly developed country will have the
wealth and resources to provide services and a good quality of life that lead to a prolonged life. This includes good
healthcare, access to sanitation, access to proper housing, a varied diet, lower levels of pollution, and good care for the
elderly. Initially, crude rates will appear low since people continue to age and less people are dying at the younger age as
they once did. However, as much of the population reaches old age, they start to die, leading to a rise in the death rate. For
example, Japan has one of the highest death rates globally, owing to their rapidly ageing population, even though they are
one of the most developed and technologically advanced countries in the world.
, GLOBAL DISTRIBUTION AND PATTERNS OF DISEASES
MALARIA
What is malaria
Malaria is an infectious, communicable disease
Malaria mostly spreads to people through the bites of some infected female Anopheles mosquitoes. Blood transfusion and
contaminated needles may also transmit malaria.
In 2021, nearly half of the world’s population was at risk of malaria. That year, there was an estimated 247 million cases of
malaria worldwide
The estimated number of deaths from malaria in 2021 was 619,000
Patterns of distribution
The world health organisation African region carries a disproportionately high share of the malaria burden. In 2021, the
region was home to 95% of malaria cases and 96% of malaria deaths. Children under 5 accounted for 80% of all the deaths
in the region
Malaria occurs mostly in poor tropical and subtropical areas of the world.
In many of the countries affected by malaria, it is a leading cause of illness and death.
In areas with high transmission, the most vulnerable groups are young children, who have not developed immunity to
malaria yet, and pregnant women, whose immunity has been decreased by pregnancy.
Four African countries accounted for just over half of all malaria deaths worldwide: Nigeria (31.3%), the Democratic
Republic of the Congo (12.6%), United Republic of Tanzania (4.1%) and Niger (3.9%).
Malaria transmission occurs in countries close to the equator, between the tropic of cancer and capricorn. This includes
central Africa, India, northern brazil, colombia, and south east Asia (eg Thailand and Indonesia)
In 2021, 35 countries reported fewer than 1000 indigenous cases of the disease, up from 33 countries in 2020 and just 13
countries in 2000.
Countries that have achieved at least 3 consecutive years of zero indigenous cases of malaria are eligible to apply for the
WHO certification of malaria elimination. Since 2015, 9 countries have been certified by the WHO Director-General as
malaria-free, including Maldives (2015), Sri Lanka (2016), Kyrgyzstan (2016), Paraguay (2018), Uzbekistan (2018), Argentina
(2019), Algeria (2019), China (2021) and El Salvador (2021).
Reasons for this pattern
The 2 core interventions for malaria control and elimination are insecticide-treated nets (ITNs) and indoor residual spraying
(IRS).
