Transcript Microorganisms affecting human health

Man And Biology
Content
• Biology And Human Welfare
•Biotechnology The Genetic Engineering
•Use Of Bacteria And Fungi
•Role Of The Biology In Economic Development
•Chemical And Biological Control Of Pests
•Biology And Conservation Of Environment
•Pollution
•Types Of Pollutants And Their Sources
•Control And Preventive Measures
•Organisms Affecting Human Health
•Common Diseases Caused By Viruses
•Antibiotics And Their Importance
Biology And Human Welfare
Biology
The study of living organisms, divided into
many specialized fields that cover their
morphology, physiology, anatomy, behavior,
origin, and distribution.
Biotechnology
Any technological application that uses
biological systems, living organisms or
derivatives thereof, to make or modify
products or processes for specific use.
Importance of Biotechnology
• Biotechnology has already begun to change
traditional industries such as food processing and
fermentation.
•It has also given rise to the development of a whole
new technology for industrial production of hormones,
antibiotics and other chemicals, food and energy
sources and processing of waste materials.
•This industry must be staffed by trained
biotechnologists who not only have a sound basis of
biological knowledge, but a thorough grounding in
engineering methods.
Genetics Engineering
Genetic engineering alters the genetic makeup of an organism using techniques that
remove heritable material or that introduce
DNA prepared outside the organism either
directly into the host or into a cell that is
then fused or hybridized with the host.
Role of the Biology in Economic Development
Biology tells us about humans, plants, animals, cells,
and really the entire world around us! Without biology,
we wouldn't have treatments, cures, and vaccines for
many diseases. Because of advancements in this field,
we're living life much more comfortably than people
hundreds of years ago did.
Biology continues to grow and make huge
advancements, so people hundreds of years from now
can look back on us and think, "how horrible it must
have been to live like that!"
Role of the Biology in Economic Development
Biology even studies how we interact with the nonliving world around us. With ecology, we're constantly
learning how animals use various materials around
them and even how they adapt to a changing
environment.
Biology in Agricultural Crops
Advance studies in biology especially genetic
engineering, plant and animal breeding and
biotechnology have n flounced man’s economic,
social and industrial progress. They have enabled
man to develop high yielding crops, better strains
of livestock and many other developments
beneficial to man. They are proving helpful in
meeting the demands of rapidly growing
population. Some of the contributions of biology in
the economic development of various aspects of
human life are given below.
Biology in Agricultural Crops
Forestry, fuel, furniture
Forestry is the business of cultivating trees which
provide us fuel, timber and wood products. Timber
is used for making furniture. Paper industry is also
dependent upon wood. Turpentine and resins are
extracted from many of the trees.
Biology in Agricultural Crops
Advancement in biology has helped forest
cultivators in choosing trees that fit successfully in
local habitat. Modern plant breeding techniques
have developed various varieties of plants that can
tolerate wide range of climatic conditions and are
fast growing, in addition to being of high
productivity, palatability and nutritional content. So
forest cultivators select varieties which satisfy all
their requirements.
AGRICULTURE
Food and clothing are basic necessities of mankind.
With the increase of population man thought of
securing more food by cultivating the most desirable
plants and domesticating animal breeds. Application
of the biological knowledge has enabled scientists to
increases yield of crops and to improve quality of
fruits and vegetables. In agriculture, cereal crops like
wheat, corn, rice have been selectively cultivated and
crossed with other varieties to produce super strains
capable of giving a palatable high yielding crop in a
minimal amount of time. Disease and pest resistant
varieties have been evolved by plant breeders.
Dairy, poultry and fish farming
Biology is playing very important role in the
economic development, in the field of poultry, dairy
and fish farming. By the use of animal breeding
technology, cross breeds of different animals have
been raised which provide better protein source in
the form f meat and high milk production in the case
of cattle, eggs and meat production in the case of
poultry and wool & meat in the case of sheep. The
cross breeds are more resistant to disease.
Acid Rain
Acid rain is a result of air pollution. When any type
of fuel is burnt, lots of different chemicals are
produced. The smoke that comes from a fire or the
fumes that come out of a car exhaust don't just
contain the sooty grey particles that you can see they also contains lots of invisible gases that can be
even more harmful to our environment.
which is why it is known as "acid rain".
Acid Rain
Power stations, factories and cars all burn fuels and
therefore they all produce polluting gases. Some of
these gases (especially nitrogen oxides and sulphur
dioxide) react with the tiny droplets of water in
clouds to form sulphuric and nitric acids. The rain
from these clouds then falls as very weak acid -
How acidic is acid rain?
Acidity is measured using a scale called the pH
scale. This scale goes from 0 to 14. 0 is the most
acidic and 14 is the most alkaline (opposite of
acidic). Something with a pH value of 7, we call
neutral, this means that it is neither acidic nor
alkaline.
Very strong acids will burn if they touch your skin
and can even destroy metals. Acid rain is much,
much weaker than this, never acidic enough to burn
your skin.
How acidic is acid rain?
Rain is always slightly acidic because it mixes with
naturally occurring oxides in the air. Unpolluted rain
would have a pH value of between 5 and 6. When
the air becomes more polluted with nitrogen oxides
and sulphur dioxide the acidity can increase to a pH
value of 4. Some rain has even been recorded as
being pH2. Vinegar has a pH value of 2.2 and lemon
juice has a value of pH2.3.
Restoring the Damage done by Acid Rain?
Lakes and rivers can have powdered limestone
added to them to neutralise the water - this is called
"liming". Liming, however, is expensive and its
effects are only temporary - it needs to be continued
until the acid rain stops. The people of Norway and
Sweden have successfully used liming to help restore
lakes and streams in their countries. A major liming
programme is currently taking place in Wales.
Greenhouse effect
The greenhouse effect is a natural process that
warms the Earth’s surface. When the Sun’s energy
reaches the Earth’s atmosphere, some of it is
reflected back to space and the rest is absorbed and
re-radiated by greenhouse gases.
Greenhouse gases include water vapour, carbon
dioxide, methane, nitrous oxide, ozone and some
artificial chemicals such as chlorofluorocarbons
(CFCs).
Greenhouse effect
The absorbed energy warms the atmosphere and
the surface of the Earth. This process maintains the
Earth’s temperature at around 33 degrees Celsius
warmer than it would otherwise be, allowing life on
Earth to exist.
Enhanced
Greenhouse
greenhouse
effecteffect
The problem we now face is that human activities –
particularly burning fossil fuels (coal, oil and natural
gas), agriculture and land clearing – are increasing
the concentrations of greenhouse gases. This is the
enhanced greenhouse effect, which is contributing
to warming of the Earth.
Enhanced
Greenhouse
greenhouse
effecteffect
Greenhouse effect
Step 1: Solar radiation reaches the Earth's
atmosphere - some of this is reflected back into
space.
Step 2: The rest of the sun's energy is absorbed by
the land and the oceans, heating the Earth.
Step 3: Heat radiates from Earth towards space.
Step 4: Some of this heat is trapped by greenhouse
gases in the atmosphere, keeping the Earth warm
enough to sustain life.
Enhanced
Greenhouse
greenhouse
effecteffect
Step 5: Human activities such as burning fossil fuels,
agriculture and land clearing are increasing the
amount of greenhouse gases released into the
atmosphere.
Step 6: This is trapping extra heat, and causing the
Earth's temperature to rise.
Ozone Depletion
Ozone layer depletion, is simply the wearing out
(reduction) of the amount of ozone in the stratosphere.
Unlike pollution, which has many types and causes, Ozone
depletion has been pinned down to one major human activity.
Industries that manufacture things like insulating foams,
solvents, soaps, cooling things like Air Conditioners,
Refrigerators and ‘Take-Away’ containers use something called
chlorofluorocarbons (CFCs). These substances are heavier
than air, but over time, (2-5years) they are carried high into
the stratosphere by wind action.
Ozone Depletion
Depletion begins when CFC’s get into the
stratosphere. Ultra violet radiation from the sun
breaks up these CFCs. The breaking up action releases
Chlorine atoms. Chlorine atoms react with Ozone,
starting a chemical cycle that destroys the good ozone
in that area. One chlorine atom can break apart more
than 100,000 ozone molecules.
Soil erosion
Soil erosion occurs when soil is removed through
the action of wind and water at a greater rate than
it is formed.
Soil
The soil covering the surface of the earth has taken
millions of years to form and we must learn to respect
it.
Soil is formed at a rate of only 1 cm every 100 to 400
years and it takes 3 000 to 12 000 years to build enough
soil to form productive land. This means that soil is a
nonrenewable resource and once destroyed it is gone
forever.
What is soil erosion?
When a raindrop hits soil that is not protected by a
cover of vegetation and where there are no roots to
bind the soil, it has the impact of a bullet.
• Soil particles are loosened, washed down the slope
of the land and either end up in the valley or are
washed away out to sea by streams and rivers.
• Erosion removes the topsoil first. Once this
nutrient-rich layer is gone, few plants will grow in
the soil again.
• Without soil and plants the land becomes desertlike
and unable to support life.
Causes of soil erosion
Erosion occurs when farming practices are not
compatible with the fact that soil can be washed
away or blown away. These practices are:
• Overstocking and overgrazing
• Inappropriate farming techniques such as deep
ploughing land 2 or 3 times a year to produce
annual crops
• Lack of crop rotation
• Planting crops down the contour instead of along it.
Ways to reduce the soil erosion
1. Minimum tillage. The less you tear up the top
layers of soil, the more resistant that soil is to
water runoff. –Despite my last name, I
encourage no-till whenever possible.
2. Stubble mulching. Putting that harvest waste
back onto the ground provides an additional
layer of insulation against environmental
effects.
3. Contour cultivation. It’s not suited for all
farmland, but it can reduce erosion by 25% to
90% when done properly.
Ways to reduce the soil erosion
4. Rotate foraging animals in fields before the pasture
is depleted.
5. Plant filter strip in low lying gullies and runoff areas
of your fields.
6. Plant grasses and small trees on those steep slopes.
7. Use strip cropping to control erosion in windy
areas.
8. Consider using a cover crop (especially legumes)
during off season times.
9. Plant tree line windbreaks, or keep the ones you’ve
got.
Population pressure on the environment
As the century begins, natural resources are under
increasing pressure, threatening public health and
development. Water shortages, soil exhaustion, loss
of forests, air and water pollution, and degradation of
coastlines afflict many areas. As the world’s
population grows, improving living standards
without destroying the environment is a global
challenge.
Population pressure on the environment
Most developed economies currently consume
resources much faster than they can regenerate.
Most developing countries with rapid population
growth face the urgent need to improve living
standards.
Environment getting worse
In the past decade in every environmental sector,
conditions have either failed to improve, or they
are worsening.
Public health , Food supply, Freshwater:
Conservation Principles, Policies and
Guidance
Conservation of Non-renewable resources:
1. Energy Conservation:
The question of is how much energy necessarily
involves a basic issue concerning man, his life style,
and his environment. Similarly, the question of how
much energy is needed to keep these wheels of
society well lubricated and moving is one of the
difficult questions.
Conservation Principles, Policies and
Guidance
The type of energy conservation includes the
following measures:
(a) Improving the efficiency of energy supply
systems,
(b) Decreasing the energy-intensiveness of a given
standard of living through acceptable lifestyle
changes (e.g., thermostat settings, lighting levels,
or smaller cars and car-pooling), and
(c) Shifting from gas or electricity to solar energy
system.
Specific energy conservation actions are deemed
desirable if one of the two criteria is met:
(a) The value of the energy saved equals or exceeds
the additional operating cost or investment (both
appropriately discounted) required to achieve it;
(b) Compared to the alternate measure to increase
energy supply; and
(c) The particular conservation option is superior in
terms of total cost (including capital investment,
energy price, economic and environment impacts)
of non-exhaustive source of energy.
Conservation of Renewable Resources:
Conservation of land, soil, minerals, water,
vegetation and wildlife which is very essential in
ensuring a continuous yield of plants used as food
and other materials for the growing population.
Conservation of Renewable Resources:
1. Soil Conservation:
• Soil is the top cover of the earth in which plants
can grow. Top soil is essential for the growth of
plants which in turn provides food for human
beings and animals. But rain water, wind and other
natural forces gradually erode the top soil.
Farmers can reduce soil erosion by planting trees,
strip cropping and crop rotation methods etc.
Conservation of Renewable Resources:
2. Water Conservation:
Conjunctive use of surface and ground water should be
encouraged to atomize the water use and to alleviate
the degradation of water and soil resources.
Some of the measures include:
(a) Avoiding wastage of water, and encourage recycling
of water;
(b) Reducing water pollution by treating sewage and
factory wastes before disposing them; and
(c) Adopting various technologies for groundwater
recharge such as use of dug-wells and ponds.
Conservation of Renewable Resources:
3. Forests Conservation:
Forests are homes for a number of wild animals. For
man, these provide fuel, coal, timber, paper, rubber
and lac, etc. They protect water loss from top soil
and thus prevent formation of deserts. They help in
regulating rainfall, avoid erosion, silting of streams
and floods.
Conservation of Renewable Resources:
4. Fish Conservation:
Man is trying to supplement his existing food resources
through an increased yield of fish from ponds, lakes,
rivers and seas. In his own interest, man has reduced
the number of certain species of fish by overfishing.
The number of reduced varieties can be restored by
implementing the following steps:
(a) Regulation of rate of fishing and of fish production.
(b) Prohibition of overfishing.
(c) Taking fish of the optimum size. Very young and
sexually mature fishes should not be caught.
(d) Rate of fish breeding should be increased.
Conservation
Conservation is the wisely regulated use of
natural resources of the environment. The
natural resources are of two types, Renewable
and Non renewable.
The important renewable natural resources are
air, water , soil, wildlife and forest.
The non renewable resources are fossil fuel
and minerals.
The need and principles of conservation
Conservation is the wisely regulated use of
natural resources of the environment. The
natural resources are of two types, Renewable
and Non renewable.
The important renewable natural resources are
air, water , soil, wildlife and forest.
The non renewable resources are fossil fuel
and minerals.
Recycling
It is a process to convert (waste) into
reusable material.
What materials can be recycled?
Glass
Paper
Aluminum
Asphalt
Iron
Textiles
Recycling Techniques
There are many different ways that materials can be
recycled. The technique that is used to create the new
materials from the old depends on what the material is. Here
is a list of different techniques:
Battery Recycling
Concrete Recycling
Recycling Techniques
Electronic Waste Recycling
Printer & Ink Cartridges
Glass
Recycling Techniques
Paper
Ferrous Materials
Plastic
Recycling Techniques
Textile Recycling
Ship breaking
Biological Sewage Treatment
Ship breaking
a method of purifying domestic and industrial sewage, con
sisting of biochemical decomposition(mineralization) by
microorganisms of organic substances (impurities of orga
nic origin) dissolved
and emulsified in sewage. Microorganisms (bacteria) use
these substances as sources of food and
energy for their life processes. In the process of the micro
organisms’ respiration, organic
substances are oxidized and energy necessary for their life
functions is released. Part of this energy
is used for the processes of synthesizing cellular substance
s, that is, for increasing the mass of
bacteria, the quantity of active sludge, and the thickness of
the biologic film in the purifying structures.
Biological Sewage Treatment
Bacteria that participate in the mineralization of org
anic compounds in sewage may bedivided into two
groups, according to their relationship to oxygen: ae
robs (which use oxygendissolved in water for respir
ation) and anaerobes (which develop in the absence
of free oxygen).
Besides dissolved organic substances, sewage contains
suspended substances, tars, and must be removed bef
ore biologic treatment. For this purpose, gratings, sand
traps, and settling tanks are used.
Some of the major process of secondary or biological
treatment are as follows: (i) Activated Sludge Process
(ii) Trickling Filters
(i) Activated Sludge Process:
The essential features of activated sludge process are: an
aeration stage, solids- liquid separation following
aeration, and a sludge recycle system. Wastewater after
primary treatment enters an aeration tank where the
organic matter is brought into intimate contact with the
sludge from the secondary clarifier. This sludge is heavily
laden with micro-organisms which are in an active state of
growth. Air is introduced into the tank either in the form
of bubbles through diffusers or by surface aerators.
• The micro-organisms utilize the oxygen in the air and
convert the organic matter into stabilized, low-energy
compounds such as NO3, SO4, and CO2and synthesize
new bacterial cells. The effluent from the aeration tank
containing the flocculent microbial mass, known as
sludge, is separated in a settling tank, sometimes called
a secondary settler or a clarifier. In the settling tank the
separated sludge exits without contact with the organic
matter and becomes activated.
• A portion of the activated sludge is recycled to the
aeration tank as a seed; the rest is wasted. If all the
activated sludge is recycled, then the bacterial mass
would keep increasing to the stage where the system
gets clogged with solids. It is, therefore, necessary to
‘waste’ some of the micro- organisms, and this wasted
sludge is the one which is processed and disposed of.
(ii) Trickling Filters:
• The secondly commonly used biological waste
treatment process is the trickling filter method.
Trickling filters are also called percolating filters. It
has good adaptability to handle peak shock loads and
the ability to function satisfactorily after a short
period of time.
• Milk processing, paper mill and pharmaceutical
wastes are among those treated by tricking filters.
Conventional trickling filters normally consist of a
rock bed, 1 to 3 metres in depth, with enough openings between rocks to allow air to circulate easily.
(ii) Trickling Filters:
• The influent is sprinkled over the bed packing ,which
is coated with a biological slime. As the liquid trickles
over the packing, oxygen and the dissolved organic
matter diffuse into the film to be metabolized by the
micro-organisms in this slime layer. End products
such as NO3, CO2 etc., diffuse back out of the film
and appear in the filter effluent.
Organisms affecting human health
• Causative agent
Different strains of viruses are responsible for
causing the disease . The disease is spread by
droplet infection (cough, sneezing, and breath).
• Treatment and control
There is no particular treatment of the disease.
The patient develops immunity and recovers.
Rest is the only immediate treatment. Disease
can be controlled by keeping patient away from
other people.
Organisms affecting human health
• Measles
Measles is a very infectious and worldwide
disease of children. The disease starts with fever
with cold, cough and a watery discharge from the
eyes. On the third day rashes appear first on the
face and then spread over the whole body.
• Causative organism
The causative organism is a virus, which is air
born and is inhaled in droplets. The disease
spreads through the discharge from eyes and
nose, which becomes air-born and spreads
rapidly.
Organisms affecting human health
Treatment and control
There is no specific treatment. Child develops
immunity and the signs and symptoms of the
disease disappear after seven days. The child should
be given plenty of drink especially milk.
It is difficult to control the disease because it is
highly infectious as the patient becomes infectious
about 2 days before the symptom of the disease
develop.
Organisms affecting human health
• Poliomyelitis
Poliomyelitis is most common among the
children but young and old people can also
become its victims.
It begins slowly. The sufferer has very high fever,
headache, nausea, fits and stiffness of limbs. In
severe cases, the virus attacks the nerve fibers of
the spinal cord causing paralysis of the limbs and
muscles of the respiratory tract, sometime
proving fatal, apart from permanent disabilities.
Organisms affecting human health
• Treatment and control
There are two polio vaccines; Sabin vaccine and
Salk vaccine. Sabin vaccine is more common and
is given orally in the form of drops. Two or three
drops are given to infants during their first year
which provides life long protection against polio
by developing active immunity against it. Salk
vaccine is injected in to the body but it is not
being practiced in our country.
Organisms affecting human health
• Causative organism
Poliomyelitis is caused by virus, which as
transmitted by infected water. It is also
transmitted b droplet infection during coughing
and sneezing, of the patient.
Microorganisms affecting human health
• Microorganisms or microbes are
microscopic organisms that exist as unicellular,
multicellular, or cell clusters. Microorganims are
widespread in nature and are beneficial to life,
but some can cause serious harm. They can be
divided into six major types: bacteria, archaea,
fungi, protozoa, algae, and viruses .
Microorganisms affecting human health
Bacteria
• Bacteria are unicellular organisms. The cells are
described as prokaryotic because they lack a nucleus.
They exist in four major shapes: bacillus (rod shape),
coccus (spherical shape), spirilla (spiral shape),
and vibrio (curved shape). Most bacteria have
a peptidoglycan cell wall; they divide by binary
fission; and they may possess flagella for motility.
The difference in their cell wall structure is a major
feature used in classifying these organisms.
Microorganisms affecting human health
Fungi
Fungi (mushroom, molds, and yeasts)
are eukaryotic cells (with a true nucleus). Most fungi are
multicellular and their cell wall is composed of chitin. They
obtain nutrients by absorbing organic material from their
environment (decomposers), through symbiotic relationships
with plants (symbionts), or harmful relationships with
a host (parasites). They form characteristic filamentous tubes
called hyphae that help absorb material. The collection of
hyphae is called mycelium. Fungi reproduce by
releasing spores.
Microorganisms affecting human health
Protozoa
• Protozoa are unicellular aerobic eukaryotes. They have a
nucleus, complex organelles, and obtain nourishment by
absorption or ingestion through specialized structures. They
make up the largest group of organisms in the world in
terms of numbers, biomass, and diversity. Their cell walls
are made up of cellulose.Protozoa have been traditionally
divided based on their mode of locomotion: flagellates
produce their own food and use their whip-like structure to
propel forward, ciliates have tiny hair that beat to
produce movement, amoeboids have false feet or
pseudopodia used for feeding and locomotion, and
sporozoans are non-motile. They also have different means
of nutrition, which groups them as autotrophs or
heterotrophs.
Microorganisms affecting human health
Algae
• Algae, also called cyanobacteria or blue-green
algae, are unicellular or multicellular
eukaryotes that obtain nourishment
by photosynthesis. They live in water, damp
soil, and rocks and produce oxygen
and carbohydrates used by other organisms. It
is believed that cyanobacteria are the origins
of green land plants.
Harmful effects of pathogens on food , crop and property
• Food spoilage
Food spoilage is the process of change in the physical and
chemical properties of the food so that it becomes unfit for
consumption. Food spoilage is any undesirable change in food.
Most natural foods have a limited life: for example, fish, meat,
milk and bread are perishable foods, which means they have a
short storage life and they easily spoil. Other foods also
decompose eventually, even though they keep for a
considerably longer time. The main cause of food spoilage is
invasion by microorganisms such as fungi and
bacteria.
Harmful effects of pathogens on food , crop and property
• prevention
For the protection of food from microbial
contamination and spoilage, it can be preserver
by the following methods.
1.Prevention of contamination methods.
2.Killing of microorganisms by boiling,
exposing to steam under pressure ,Pasteuriation
and radiation.
Some common diseases caused by pathogenic worm
Threadworm Infection
Definition
Threadworm infection is an intestinal disease,
which occasionally spreads to the skin, caused by
a type of parasitic roundworm (helminth). In untr
eated patients, the disease has a high rate of rein
fection caused by worms already present in the body.
This type of disease recurrence iscalled autoinfection. Be
cause of autoinfection, threadworms can remain inside
humans for aslong as 45 years after the initial infestation.
Some common diseases caused by pathogenic worm
Treatment
Threadworm infections are treated with medications.
FLATWORMS
• Flatworms are the simplest of the worm groups.
There are about 20,000 species in this group.
They are found many places and can be free
living or parasitic. A parasite lives off of another
living thing called a host and can be harmful.
One of the best known flatworms is the
tapeworm. The tapeworm can get into a person's
digestive tract and grow to enormous lengths.
The tapeworm then eats off the host and is
dangerous to the host as it grows and consumes
more of the host and its food.
• Flatworms are found in marine and fresh water.
Roundworms
Phylum Nematoda
• Roundworms are a member of the
nemathelminths phylum or group of animals. The
hookworm, pinworm and trichinella are part of
this group. They are more advanced than
flatworms but less advanced than earthworms.
They have thin round bodies, with none of the
pieces or segments that earthworms have in their
bodies.
• Roundworms live in salt water, fresh water and the
soil. Many of them are harmful to man as they are
parasites.
CONTROL
• The personal hygiene proper disposal of human
faeces and thoroughly washed and properly
cooked fruit and vegetable are key to control its
infection.
Diseases transmitted by insects and ticks
Insects (mosquitoes, lice, fleas, bed bugs) and ticks
are able to transmit a number of diseases caused by
infectious agents: viruses (chikungunya virus, yellow
fever, dengue fever, etc.), bacteria (Lyme disease,
plague, etc.), parasites (malaria, sleeping sickness,
leishmaniasis, filariasis, etc.).
Diseases transmitted by insects and ticks
Mosquitoes
There are different species of mosquitoes (Anopheles,
Aedes, Culex) and these have completely different
preferred habitats, times when they are active and
types of bite. The lavae that produce the adults
develop in areas of stagnant water (receptacles,
reservoirs, ponds, lakes, etc.). They transmit certain
specific diseases according to the specific species, climate
and habitat: malaria (Anopheles), chikungunya virus,
dengue fever, yellow fever, Japanese encephalitis,
lymphatic filariasis.
Diseases transmitted by insects and ticks
Mosquitoes
Some other diseases transmitted by mosquitoes in humans
are yellow fever, dengue and filariasis etc.
Control:
1. Personal protection to avoid mosquito bite. Use of
mosquito nets.
2. Killing of adults mosquitoes by using insecticides
fumigation
3. Killing of larvae by use of insecticide.
4. Elimination of breeding places. Filling water bodies
with earth or srteening water surface with insecticides.
Diseases transmitted by insects and ticks
Mosquitoes
Some other diseases transmitted by mosquitoes in
humans are yellow fever, dengue and filariasis etc.
Control:
5. Preventive medicine to enhance immunity against
infection.
6. Use of mosquito repelling chemicals.
7. Biological control by introducing organisms eating
upon the eggs and larvae of mosquitoes.
HOUSE FLY
• Flies are the carriers of very deadly diseases, they
infest meat and other food items, some of their
species also spread food poisoning bacteria like
Salmonella enteritidis.
• The habitat of flies make them perfectly suited for
spreading diseases. Fly is a restless insect, it moves
back and forth between food and filth and this helps
it in spreading infections faster. It is attracted to the
food by its sense of smell, however it cannot eat
solid food. When it reaches the food it vomits on the
solid food and creates a solution of it, then sucks it
and thus contaminates the food.
HOUSE FLY
• Below, I have highlighted some diseases that are
caused by flies:
• Flies can cause typhoid and paratyphoid fevers.
• They can also spread some other diseases like diarrhea
and dysentery, cholera, conjunctivitis etc. by
mechanical contamination.
• Other diseases carried by house flies include
salmonella, anthrax and tuberculosis.
• They are also known to transmit the eggs of parasitic
worms.
• Sand flies found in South America, Africa and Europe
are carriers of a micro-organism responsible for a
disease that eats away the human skin. This disease is
known as Leishmaniasis.
HOUSE FLY
1. By protecting contamination of food by flies.
2. Control breeding of flies.
3. Killing adult flies (by spraying)
BACTERIA TYPES
• Bacteria that cause disease are broadly classified according to
their shape. The four main groups include:
• Bacilli – shaped like a rod with a length of around 0.03mm.
Illnesses such as typhoid and cystitis are caused by bacilli strains.
• Cocci – shaped like a sphere with a diameter of around 0.001mm.
Depending on the sort, cocci bacteria group themselves in a
range of ways, such as in pairs, long lines or tight clusters.
Examples include Staphylococci (which cause a host of infections
including boils) andGonococci (which cause the sexually
transmissible infection gonorrhoea).
• Spirochaetes – as the name suggests, these bacteria are shaped
like tiny spirals. Spirochaetes bacteria are responsible for a range
of diseases, including the sexually transmissible infection syphilis.
• Vibrio – shaped like a comma. The tropical disease cholera,
characterised by severe diarrhoea and dehydration, is caused by
the vibrio bacteria.
BACTERIA TYPES
Examples
• Bacillus anthracis — the causative agent of anthrax in
humans and animals.
• Clostridium botulinum — releases the most
powerful neurotoxin leading to death from botulism.
• Mycobacterium tuberculosis — the causative agent of most
cases of tuberculosis
• Mycobacterium leprae — the bacterium that
causes leprosy (Hansen's disease)
• Yersinia pestis — pneumonic, septicemic and the
notorious bubonic plagues (aka "Black Death")
• Rickettsia prowazekii — the etiologic agent of typhus fever
• Bartonella spp.
CHOLERA
Cholera is an infectious disease that causes severe
watery diarrhea, which can lead to dehydration and
even death if untreated. It is caused by eating food
or drinking water contaminated with a bacterium
Called Vibrio cholerae.
CHOLERA
Cholera Causes
• Vibrio cholerae, the bacterium that causes cholera, is
usually found in food or water contaminated by feces
from a person with the infection. Common sources
include:
• Municipal water supplies
• Ice made from municipal water
• Foods and drinks sold by street vendors
• Vegetables grown with water containing human wastes
• Raw or undercooked fish and seafood caught in waters
polluted with sewage
CONTROL
Prevention of cholera is dependent on access to safe
water, adequate sanitation, and basic hygiene needs.
The following materials cover the basics of cholera
and other diarrheal disease prevention.
TYPHOID
Typhoid fever is an infectious disease caused by the
bacteria Salmonella typhi. It is also known as enteric
fever, or commonly just typhoid. Typhoid fever and
paratyphoid fever are clinically indistinguishable
diseases, collectively called enteric fever. It easily
spreads through contaminated food and water
supplies and close contact with others who are
infected.
SOME COMMON DISEASES CAUSED BY VIRUSES
INFLUENZA
The 1918 flu pandemic, commonly referred to as the
Spanish flu was such a pandemic. It was caused by an
unusually severe and deadly influenza A virus. The
victims were often healthy young adults in contrast
from weakened and elderly who are usual victims. It
killed around 100 million people or at least 5% of the
world's population in 1918.
CONTROL
Since the disease spreads in places where human
feces come into to contact with food and drinking
water, prevention relies on careful food preparation
and persistent hand washing. To prevent typhoid, people
in endemic areas should avoid drinking untreated water,
avoid raw fruits and vegetables, choose to consume hot
foods where bacteria cannot survive, adequately clean
household items, and avoid handling food if there is a
risk of spreading the disease.
Common Colds
• Common colds are the most seen diseases caused by
viruses. Characterized by a runny nose, cough and sore
throat, although harmless the common cold virus is
caused by more than 200 viruses. This is an airborne
infection and is transmitted through the nose and
mouth.
Chickenpox
• This virus can be spread to another person in 48
hours. It affects millions of children across the world
annually. Its symptoms include red rashes with blisters
accompanied by fever, headaches, cough and loss of
appetite. The virus affects the chest, face, scalp and
back areas.
Influenza
• The influenza virus affects large populations annually.
Characterized by fever, headaches, muscle aches and
sore throat, it is spread through the air when infected
people cough or sneeze. It also leads to vomiting,
nausea and diarrhea.
Hemorrhagic Fever
• This is a deadly virus that can cause internal and
external bleeding. It affects the vital internal organs of
a human body especially the liver, kidneys and lungs.
Although it starts with muscle aches and fever, it later
affects the vascular system of the body. Once it gets in,
it can make the blood vessels porous causing the
patients to bleed from under the skin, in the eyes and
mouth, both internally and externally.
• Viral Hepatitis
• This inflammation of the liver is caused by 5 viruses namely,
hepatitis A, B, C, D and E. It also results from other types of
viral infections like the herpes simplex, yellow fever, EpsteinBarr and cytomegalovirus. Each of these has its own
symptoms ranging from jaundice, low immunity and
cirrhosis. It can be contracted through sexual contact and
through blood. There are a variety of treatments available
including antiviral vaccines.
• Herpes Simplex
• Caused by the sexually transmitted herpes simplex virus
(HSV), it affects the genitals, mouth and face. The affected
areas include the buttocks and anal areas. Newborn babies
and people with lower immunity are more vulnerable to this
virus. It comes in two types; the genital and oral virus. In
some cases, it does not show any symptoms, but in other
cases it is represented by itchy painful blisters. It is spread
via direct contact and can be treated through medical
treatment.
Viral Pneumonia
• The pneumonia virus affects the lungs causing them to swell and become
irritated. Its symptoms feature coughs, shortness of breath, fever, and
shaking chills. It also leads to loss of appetite, fatigue, low energy and a
sharp stabbing chest pain. This inflammation is common in infants, HIV
patients, cancer patients on chemotherapy treatment, organ transplant
recipients and the aged who are vulnerable to infections. It is diagnosed by
an X-ray, CT-scan and lung biopsy among other tests. It can be treated by
antivirus medication, anti-inflammatory drugs and intake of fluids.
Yellow Fever
• Common in sub-Saharan Africa and southern America, this tropical disease
is caused by a mosquito transmitted virus. Its symptoms occur in stages
including headache, muscle and joint aches, loss of appetite, vomiting,
jaundice and fever. It leads to heart, kidney and liver failure, bleeding
disorders, seizures and comas. It is diagnosed through a blood test and
treatment is for the symptoms but no certain solution to yellow fever. It
can be prevented by using a mosquito net and vaccination.
Rabies
• This is one of the fatal diseases caused by viruses, which is evolved from
infected animal bites. Its symptoms include fever, headache, agitation,
excessive saliva, hallucinations, partial paralysis, and hydrophobia.
Immediate medical attention is necessary.
Meningitis
• This enterovirus affects the protective cover around the spinal
cord, brain and cerebrospinal fluid, i.e. the meninges. It affects
the fluid surrounding the brain exposing it to the deadly
meningitis caused by virus. It is a contagious disease, whose
symptoms include high fever, neck stiffness, nausea, vomiting,
and drowsiness.
AIDS
• The fatal illness caused is by HIV (human immunodeficiency
virus). HIV has adverse symptoms that include fever, rash,
headache, sore throat, fever, mouth and genital ulcers, swollen
lymph glands, joint pain, fatigue, weight loss, and diarrhea. After
about 10 years later, untreated HIV becomes AIDS and its
symptoms include chronic diarrhea, cough and shortness of
breath, headache, skin rashes, blurred vision, unexplained
fatigue, shaking chills and soaking night sweats. This condition
should be treated in its earliest HIV stages to hinder its
progressive development to AIDS.
Measles
• Characterized by cough, running nose, fever, inflamed eyes,
and reddish skin rash, measles is caused a virus. Also
referred to as rubeola, this disease is quite fatal in small
children below 5 years. It is a children's infection that can be
prevented by a vaccine.
Viral Gastroenteritis
• Also known as the stomach flu, its signs include watery
diarrhea, nausea, vomiting, abdominal crumbs, and fever.
This is an intestinal infection spread through bodily contact
and infected food or water. Like all other viral infections, it
has no sure treatment hence preventive measures should be
observed. Children, the aged, and lower immune persons
are more susceptible to infection. Proper hand washing
routine and food preparation hygiene are effective ways to
prevent this disease.