ppt slides

1. DISEASE
PREVENTION
AND CONTROL

2. PATHOGENS
• A pathogen is defined as an organism causing
disease to its host, with the severity of the
disease symptoms referred to as virulence.
•Pathogens are taxonomically widely diverse
and comprise viruses and bacteria as well as
unicellular and multicellular eukaryotes

3. • pathogen is any organism
that causes disease.
•Viruses, bacteria, fungi, and
parasites are all examples of
pathogens

4. Types of
pathogens
1.BACTERIA-are small single-celled
organisms.
-found almost everywhere on Earth and are
vital to the planet's ecosystems.
- Some species can live under extreme
conditions of temperature and pressure.
-The human body is full of bacteria, and in
fact is estimated to contain more bacterial
cells than human cells.

5. Types of
pathogens
-Most bacteria in the body
are harmless, and some are
even helpful.
-A relatively small number
of species cause disease.

6. Saprophytes are the living organisms that live and feed on
dead and decaying organisms.
• They are considered extremely important in soil biology.
• They break down the complex organic matter into simpler
substances that are taken up by the plants for various
metabolic activities.
• Thus, saprophytes play a significant role in the ecosystem.
Fungi and a few bacteria are saprophytes.

7. • A parasite is an organism that lives on
or in a host organism and gets its food
from or at the expense of its host.
• There are three main classes of
parasites that can cause disease in
humans: protozoa, helminths, and
ectoparasites.

8. RICKETTSIAE
• The rickettsiae are a diverse collection of
obligately intracellular Gram-negative
bacteria found in ticks, lice, fleas, mites,
chiggers, and mammals. They include the
genera Rickettsiae, Ehrlichia, Orientia,
and Coxiella. These zoonotic pathogens
cause infections that disseminate in the
blood to many organs.

9. • Rickettsia species cause Rocky Mountain
spotted fever, rickettsialpox, other spotted
fevers, epidemic typhus, and murine typhus.
• Orientia (formerly Rickettsia) tsutsugamushi c
auses scrub typhus. Patients present with
febrile exanthems and visceral involvement;
symptoms may include nausea, vomiting,
abdominal pain, encephalitis, hypotension,
acute renal failure, and respiratory distress.

10. • Rickettsia and Orientia species are
transmitted by the bite of infected
ticks or mites or by the feces of
infected lice or fleas.
• From the portal of entry in the skin,
rickettsiae spread via the
bloodstream to infect the
endothelium and sometimes the
vascular smooth muscle cells.
• Rickettsia species enter their target
cells, multiply by binary fission in
the cytosol, and damage heavily
parasitized cells directly.

11. VIRUSES
• virus is an infectious agent that can only
replicate within a host organism.
• can infect a variety of living organisms,
including bacteria, plants, and animals.
• are so small that a microscope is
necessary to visualize them, and they
have a very simple structure.

12. • When a virus particle is independent from its host, it
consists of a viral genome, or genetic material, contained
within a protein shell called a capsid.
• In some viruses, the protein shell is enclosed in a membrane
called an envelope. Viral genomes are very diverse, since
they can be DNA or RNA, single- or double-stranded, linear
or circular, and vary in length and in the number of DNA or
RNA molecules.

13. • Viruses have different shapes and sizes. Scientists
categorize viruses according to various factors, including:
• their shape and size, which may be rod-shaped, almost
spherical, or other shapes the type of their nucleic acid,
which contains their genetic information whether or not
they have a protective lipid envelope derived from the host
cell
• Examples of viruses with an envelope include
the influenza virus and HIV.

14. Viruses can spread through:
• Touch: If, for example, a person has the SARS-CoV-2 virus on their hands,
and they touch their nose, mouth, or eyes, the virus can enter the body, and
they can develop COVID-19.
• Respiratory droplets: Some viruses can be present in respiratory droplets. A
person produces these when they talk, cough, or sneeze. Influenza and
SARS-CoV-2 are two examples of viruses that can spread in this way.
• Direct contact: Some viruses may spread through direct contact with a
person that has the virus. For example, the human papillomavirus (HPV) can
spread via direct contact with the skin. The Epstein-Barr virus, which
causes mononucleosis (mono), can spread through saliva, such as while kissing.

15. • Bodily fluids: HIV, for instance, can pass from one person to
another through the exchange of semen or blood.
• Contaminated food or water: Noroviruses are one type of virus that
can enter the body when a person consumes contaminated food or
water.
• Insects: Mosquitoes carry the virus that causes Zika from one
person to another.
• Around childbirth: A mother with the cytomegalovirus, which is a
herpes virus, can pass the virus on to an unborn child.

16. Viruses cause many human diseases. For example, the Epstein-Barr virus can lead
to mono.
Other viral diseases include:
• COVID-19 smallpox the common cold different types of flu
measles mumps Rubella chickenpox
Hepatitis herpes simplex virus Polio rabies
• Ebola hantavirus HIV SARS
dengue fever Zika

17. fungi
• A fungus is any member of the group of eukaryotic
organisms that includes microorganisms such as
yeasts and molds, as well as the more familiar
mushrooms.
• These organisms are classified as one of the
traditional eukaryotic kingdoms, along with
Animalia, Plantae and either Protista or Protozoa
and Chromista

18. • Fungi are living things that are classified separately from
plants or animals. They move around by spreading out or
sending spores (reproductive parts) into the air or
environment. Many fungi live naturally in our body (mouth, GI
tract, skin) but can overgrow under certain circumstances.
• Scientists estimate that there are millions of fungi in the
world, but only a small number of them are known to cause
disease in people. This includes certain yeasts and molds.

19. • Fungal infections are any disease or condition
you get from a fungus.
• They usually affect your skin, hair, nails or
mucous membranes but they can also infect
your lungs or other parts of your body. You're
at higher risk for fungal infections if you have
a weakened immune system.

20. • What does a fungal infection look like?
• Fungal infections on or in your skin can look red, swollen or
bumpy.
• They can look like a rash or you might be able to see a lump
under your skin. Fungal infections in your nails can make
them discolored (yellow, brown or white), thick or cracked.
Fungal infections in your mouth or throat can cause a white
coating or patches.

22. Who is most at risk for fungal infections?
• Anyone can get a fungal infection, especially ones that affect your
skin or nails. Fungal infections are more common in places on your
body that trap moisture or have a lot of friction. You’re at higher risk
for infection, especially severe ones, if you have poor circulation or
diabetes, or if you have a weakened immune system from:
• HIV/AIDS.
• Cancer or cancer treatments.
• Immunosuppressant medications (for autoimmune conditions or
organ, stem cell or bone marrow transplants).

23. PROTOZOA
• Protozoa are one-celled animals found worldwide in most habitats.
Most species are free living, but all higher animals are infected with
one or more species of protozoa.
• Infections range from asymptomatic to life threatening, depending on
the species and strain of the parasite and the resistance of the host.

24. • Protozoan parasites that are infectious to humans represent
a significant threat to health and cause more than a million
deaths annually (Lozano et al., 2012).
• They also threaten the lives of billions world-wide and are
associated with significant morbidity and large economic
impacts (World Health Organization, 2010b; Murray et al.,
2012b).

25. Diseases caused by a
protozoa
1.Malaria is the most significant of the protozoan
parasites that infect man.
• Found in tropical and sub-tropical regions of the
world, malaria parasites threaten the lives of 3.3
billion and cause ∼0.6–1.1 million deaths annually
• Similar to other protozoan infections of man, the
treatment of malaria is dependent on chemotherapy.
While substantial funds have been invested in
producing a malarial vaccine, to date poor efficacy
has been achieved for those that have been trialled
clinically

26. • Malaria is a life-threatening disease spread to humans by
some types of mosquitoes. It is mostly found in tropical
countries. It is preventable and curable.
• The infection is caused by a parasite and does not spread
from person to person.
• Symptoms can be mild or life-threatening. Mild symptoms
are fever, chills and headache. Severe symptoms include
fatigue, confusion, seizures, and difficulty breathing.

27. •Infants, children under 5 years, pregnant
women, travellers and people with HIV or
AIDS are at higher risk of severe infection.
•Malaria can be prevented by avoiding
mosquito bites and with medicines.
Treatments can stop mild cases from getting
worse.

28. African
trypanosomiasis
• also known as African sleeping sickness, is caused by
parasitic protozoan of the genus Trypanosoma. The two
forms, West African and East African trypanosomiasis, are
caused by Trypanosoma brucei gambiense and Trypanosoma
brucei rhodesiense, respectively
• is caused by microscopic parasites of the species
Trypanosoma brucei. It is transmitted by the tsetse fly
(Glossina species), which is found only in sub-Saharan Africa.

29. C
WORMS
• Parasites are organisms that live in and feed off
a living host. There are a variety of parasitic
worms that can take up residence in humans.
• Among them are flatworms, roundworms, and
thorny-headed worms (spiny-headed worms).
• The risk of parasitic worm infection is higher in
rural or developing regions. The risk is also
greater in places where food and drinking water
may be contaminated and sanitation is poor.

30. • Intestinal worms, also known as parasitic worms,
are one of the main types of intestinal parasites in
humans. They’re most commonly found in
subtropical and tropical regions, but some types are
found in the United States.
• Most intestinal worm infections only cause mild
illness and can be treated with medication. Read on
to learn more about intestinal worms including
signs, symptoms, and treatment.
INTESTINAL WOR

31. LICE
• Lice are tiny, wingless insects that feed on human
blood.
• Lice spread from person to person through close
contact and by sharing belongings.

32. • Head lice found on the scalp. They're easiest to see at the nape of
the neck and over the ears.
• Body lice that live in clothing and bedding and move onto the skin to
feed. Body lice most often affect people who aren't able to bathe or
wash clothing often, such as homeless people.
• Pubic lice, also called crabs, that occur on the skin and hair of the
pubic area. Less often, they may be found on coarse body hair, such
as chest hair, eyebrows or eyelashes.
***Unless treated properly, lice can become a recurring problem.
Three types of lice:

33. • Common signs and symptoms of lice include:
• Intense itching on the scalp, body or in the genital area.
• A tickling feeling from movement of hair.
• The presence of lice on your scalp, body, clothing, or pubic
or other body hair. Adult lice may be about the size of a
sesame seed or slightly larger.

34. • Lice eggs (nits) on hair shafts. Nits may be difficult to see
because they're very tiny. They're easiest to spot around the
ears and the nape of the neck. Nits can be mistaken for
dandruff, but unlike dandruff, they can't be easily brushed out of
hair.
• Sores on the scalp, neck and shoulders. Scratching can lead
to small red bumps that can sometimes get infected with
bacteria.
• Bite marks, especially around the waist, groin, upper thighs
and pubic area.

35. When to see a doctor
• See your health care provider if you suspect you or your child
has lice. Things often mistaken for nits include:
• Dandruff
• Residue from hair products
• Bead of dead hair tissue on a hair shaft
• Scabs, dirt or other debris
• Other small bugs found in the hair

36. ROUND
WORMS
• Roundworms are parasites.
• They use the human body to stay
alive, feed and reproduce. If a lot of
eggs have been swallowed, or if the
worms move from the small intestine
to other parts of the body, they can
cause serious complications, such as
a bowel obstruction.

37. PINWORMS
• The pinworm, also known as threadworm or
seatworm, is a parasitic worm.
• It is a nematode and a common intestinal
parasite or helminth, especially in humans.
• The medical condition associated with pinworm
infestation is known as pinworm infection or
less precisely as oxyuriasis in reference to the
family Oxyuridae.

38. TAPEWORM
•A tapeworm is a parasite that can
live and feed in human intestines.
This is called a tapeworm infection.
•A young and inactive form of the
tapeworm is called a larval cyst. It
can stay alive in other parts of the
body. This is called a larval cyst
infection.

39. TAPEWORM
• A tapeworm in the intestines often causes mild symptoms.
Moderate to severe symptoms may include stomach pain
and diarrhea. Larval cysts can cause serious disease if they
are in a person's brain, liver, lungs, heart or eyes.
• Tapeworm infections are treated with anti-parasitic drugs.
Treatments for larval cyst infections may include anti-
parasitic drugs and surgery to remove the cyst. Other drugs
may be used to treat symptoms.

40. FLUKES
•Fluke, any member of
the invertebrate class Trematoda
(phylum Platyhelminthes), a group of
parasitic flatworms that probably
evolved from free-living forms millions
of years ago.

41. • Flukes parasitize members of all vertebrate classes but most
commonly parasitize fish, frogs, and turtles; they also parasitize
humans, domestic animals, and invertebrates such as mollusks
and crustaceans.
• Some are external parasites (ectoparasites); some attach
themselves to internal organs (endoparasites); others are semi-
external, attaching themselves to the lining of the mouth, to the
gills, or to the cloaca (the end of the digestive tract). Some
attack a single host, while others require two or more hosts.