PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY,SRI PARAMAKALYANI COLLEGE, ALWARKURICHI-627 412

3. Synopsis
• Definition
• Types
1.Baterial infection
2.Viral infection
3.Fungal infection
4.Parasitic infection

4. Definition
• The invitation and multiplication of microorganisms such as bacteria,
viruses and parasites they are not normally present within the body.
• An infection may cause symptoms and be subclinical, or it may cause
symptoms and be clinically apparent.
• An infection occurs when a microorganism enter a person’s body
cause harm.
• The microorganism uses that person’s body to sustain itself,
reproduce and colonize.
• These infectious microscopic organisms are known as PATHOGENS
and they multiply quickly.

7. Types
• Infection is caused by the influence of various microorganisms.
• The types of microorganisms that cause infections are given below,
• They are,
1. Viral Infections ,
2. Bacterial Infections,
3. Parasitic Infections ,
4. Fungal Infections and etc.,.

9. 1.Viral infection
• A viral infection is the proliferation of a harmful virus within the body.
• Symptoms of the viral illness are due to tissue damage and the
associated immune response of the host.
• Viral infections occur when a virus enters the body and successfully
takes over a host cell to begin the process of replicating.
• This can occur at the site of entry, also known as a localized infection,
or the virus can spread throughout the body, causing a systemic
infection.

10. • The virus life cycle could be divided into six steps: attachment,
penetration, uncoating, gene expression and replication, assembly,
and release.
• During attachment and penetration, the virus attaches itself to a host
cell and injects its genetic material into it.
• During uncoating, replication, and assembly, the viral DNA or RNA
incorporates itself into the host cell’s genetic material and induces it
to replicate the viral genome.
• During release, the newly-created viruses are released from the host
cell, either by causing the cell to break apart, waiting for the cell to
die, or by budding off through the cell membrane.

12. How does Viral Infection affect human body
• Viruses can be termed hijackers, as they invade healthy, living and
normal cells to produce and multiply other viruses like them. These
small infectious organisms need a living cell for reproduction.
• Hence they enter the host cell and release their DNA or RNA inside
the host cell. This DNA or RNA contains the information which is
required to replicate the virus.
• The interesting thing about viruses is that they are extremely unique
microorganisms since they cannot reproduce without a host cell. So,
after entering the host cell, the genetic material of the virus takes
charge of the host cell and compels it to replicate the virus

13. What are the different types of Viral
Infections
• The most common type of virus led infection is the Respiratory
Infection.
• Respiratory infection affects the throat, upper airways and lungs.
Most common respiratory infection includes a sore throat, common
cold, sinus, pneumonia and influenza.
• Respiratory infection causes a lot of troubles in infants, older people
and people suffering from lung or heart disorder.
• Apart from respiratory infection, these can affect other specific
parts/organs of the human body.

14. • Liver: The presence of virus in liver can result in Hepatitis.
• Gastrointestinal tract: The existence of virus in the gastrointestinal
tract, like gastroenteritis, is usually caused by rotavirus and norovirus.
• Nervous System: Certain viruses like rabies virus and west nile virus
infect human brain and cause encephalitis. There are some other
viruses as well that infect the tissue layer covering the brain and
spinal cord. These can cause meningitis.
• Skin: There are some kind of viruses that cause skin infection which
result in blemishes or warts. Many viruses that affect other body
organs/parts, like chickenpox can cause rashes on the skin.

16. What diseases are caused by viruses
• Many human diseases are caused by virus led infections.
These include:
.Smallpox .Cold
.Chickenpox .Measles
.Hepatitis .Human Papiloma Virus

17. .Influenza. .Shingles .Herpes .Polio
.Rabies .HIV (Human Immunodeficiency Virus)
.Cold Sores .Ebola .SARS (Severe Acute Respiratory Syndrome)
.Epstein-Barr Virus .Dengue .Some types of Cancer and etc.,.

20. What are the common symptoms of Viral
Infection
• High, Fever, Tiredness or Fatigue, Headache, Diarrhea,
Sore throat, Abdominal Pain, Coughing, Runny nose, Skin rash,
Nausea and vomiting, Muscle ache.
• It is important to note here that not all the people who show these
signs or symptoms need medical treatment.
• If the symptoms are mild, it is advised to wait for a few days as most
of them disappear on their own.
• This is basically due to the activation of body’s own defense
mechanism that destroys the virus and make the symptoms to fade
away.

21. When is a Viral Infection serious
• Almost every person has had a flu or a bad cold at least once in their
lifetime. So usually, a viral infection is not that serious. However, at
times, such infections can become extremely troublesome.
• Below mentioned are some of the scenarios when a virus led
infection can be considered serious:
• Complaints and symptoms lasting for more than seven days,
• High fever lasting for more than five days,
• BreathlessnessNew reddish rash or spots on the body.

22. Antiviral Medication and Other Treatment
• Many viral infections resolve on their own without treatment.
• Other times, treatment of viral infections focuses on symptom relief,
not fighting the virus.
• For example, cold medicine helps alleviate the pain and congestion
associated with the cold, but it doesn't act directly on the cold virus.
• There are some medications that work directly on viruses. These are
called antiviral medications.
• They work by inhibiting the production of virus particles.

23. • Others prevent viruses from entering host cells. There are other ways
in which these medications work.
• In general, antiviral medications are most effective when they're
taken early on in the course of an initial viral infection or a recurrent
outbreak.
• Different kinds of antiviral medications may be used to treat
chickenpox, shingles, herpes simplex virus-1 (HSV-1), herpes simplex
virus-2 (HSV-2), HIV, hepatitis B, hepatitis C, and influenza.

24. Viral Illness Prevention
• Vaccines can reduce the risk of acquiring some viral illnesses.
• Vaccines are available to help protect against the flu, hepatitis A,
hepatitis B, chickenpox, herpes zoster (shingles), cancer-causing
strains of human papillomavirus (HPV), measles/mumps/rubella
(MMR), polio, rabies, rotavirus, and other viruses.
• Vaccines vary in effectiveness and in the number of doses required to
confer protection. Some vaccines require booster shots to maintain
immunity.

26. 2.bacterial infection
• A bacterial infection occurs when bacteria enter the body, increase in
number, and cause a reaction in the body.
• Bacteria can enter the body through an opening in your skin, such as
a cut or a surgical wound, or through your airway and cause infections
like bacterial pneumonia.
• But infectious bacteria can make you ill. They reproduce quickly in
your body. Many give off chemicals called toxins, which can damage
tissue and make you sick. Examples of bacteria that cause infections
include Streptococcus, Staphylococcus, and Escherichia coli .
• Bacterial infections have a large impact on public health.

27. • Bacteria are transmitted to humans through air, water, food, or living
vectors.
• As a general rule, bacterial infections are easier to treat than viral
infections.
• Bacteria can infect any area of the body. Pneumonia, meningitis, and
food poisoning are just a few illnesses that may be caused by harmful
bacteria. Bacteria come in three basic shapes: rod-shaped (bacilli),
spherical (cocci), or helical (spirilla).

28. Symptoms
• A bacterial infection can also spread throughout the blood, triggering
a potentially life-threatening blood infection called septicemia.
• That, in turn, can lead to sepsis, a condition that happens when your
body has a severe response to an infection.
• Children and adults of any age can develop a bacterial infection.
Bacteria can infect every area of the body, including
your:Bladder ,Brain,Intestines,Lungs,Skin.

29. • Bacterial Skin Infections,
• Foodborne Bacterial Infections,
• Fever,
• swollen lymph nodes in the neck, armpits, groin or elsewhere,
• Headache,
• nausea or vomiting.

30. Bacterial Skin Infections
• Bacterial skin infections are usually caused by gram-positive strains
of Staphylococcus and Streptococcus or other organisms. Common
bacterial skin infections include:
• Cellulitis causes a painful, red infection that is usually warm to the
touch. Cellulitis occurs most often on the legs, but it can appear
anywhere on the body.
• Folliculitis is an infection of the hair follicles that causes red, swollen
bumps that look like pimples. Improperly treated pools or hot tubs
can harbor bacteria that cause folliculitis.
• Impetigo causes oozing sores, usually in preschool-aged children.
The bullous form of impetigo causes large blisters while the non-
bullous form has a yellow, crusted appearance.

31. Foodborne Bacterial Infections
• Bacterial infections are one cause of foodborne illness. Nausea,
vomiting, diarrhea, fever, chills, and abdominal pain are common
symptoms of food poisoning.
• Raw meat, fish, eggs, poultry, and unpasteurized dairy products may
harbor harmful bacteria that can cause illness.
• Unsanitary food preparation and handling can also encourage
bacterial growth.
• Bacteria that cause food poisoning include:
1. Campylobacter jejuni (C. jejuni) is a diarrheal illness often
accompanied by cramps and fever.

32. 2.Clostridium botulinum (C. botulinum) is a potentially life-threatening
oibacterium that produces powerful neurotoxins.
3.Escherichia coli (E. coli) is a diarrheal (often bloody) illness that may
baccompanied by nausea, vomiting, fever, and abdominal cramps.
4.Listeria monocytogenes (L. monocytogenes) causes fever, muscle ii
iiiand diarrhea, Pregnant women, elderly individuals, infants, and those
ii weakened immune systems are most at risk for acquiring this
iiiinfection . Iii
nfeSalmonella causes fever, diarrhea, and abdominal cramps.
Symptoms typically last between 4 and 7 days.ction

33. Fever
A person has a fever if their body temperature rises above the normal
range of 98–100°F (36–37°C). It is a common sign of an infection.
• When someone has a fever, they may also:
1. shiver and feel cold when nobody else does
2. sweat
3. have a low appetite
4. show signs of dehydration
5. have increased sensitivity to pain
6. lack energy and feel sleepy
7. have difficulty concentrating

34. swollen lymph nodes
• The lymph nodes collect and filter fluids, waste materials, and
harmful germs. The human body has hundreds of lymph nodes. The
main lymph nodes that people may see or feel are found:
1. under the jaw,
2. on each side of the neck,
3. under the armpits,
4. on either side of the groin.
• Lymph nodes also contain immune cells that help fight infection by
attacking the germs that the body’s lymph fluid has collected.

35. • The lymph nodes may swell when a person has a temporary infection.
The swelling occurs as a result of immune cell activity in the lymph
nodes.The location of the swelling often relates to the affected area.
• For example, an ear infection may cause swollen lymph nodes near
the ear, while someone with an upper respiratory tract infection may
notice swollen lymph nodes in their neck.
• Swollen lymph nodes will feel like soft, round bumps, and they may
be the size of a pea or a grape. They might be tender to the touch,
which indicates inflammation.

36. Headaches
• Headache is pain in any region of the head. Headaches may occur on
one or both sides of the head, be isolated to a certain location,
radiate across the head from one point, or have a viselike quality. A
headache may appear as a sharp pain, a throbbing sensation or a dull
ache.
• Headache caused by and occurring in association with other
symptoms and/or clinical signs of a systemic bacterial infection, in the
absence of meningitis or meningoencephalitis.

37. Antibiotics
• Antibiotics are medications that fight bacterial infections. They work
by disrupting the processes necessary for bacterial cell growth and
proliferation.
• It's important to take antibiotics exactly as prescribed. Failure to do
so could make a bacterial infection worse.
• Antibiotics don't treat viruses, but they're sometimes prescribed in
viral illnesses to help prevent a "secondary bacterial infection.“
• Secondary infections occur when someone is in a weakened or
compromised state due to an existing illness.

39. 3.Fungal infection- mycosis
• A fungus that invades the tissue can cause a disease that's confined to the
skin, spreads into tissue, bones and organs or affects the whole body.
• In humans, fungal infections occur when an invading fungus takes over an
area of the body and is too much for the immune system to handle.
• Fungi can live in the air, soil, water, and plants. There are also some fungi
that live naturally in the human body. Like many microbes, there are
helpful fungi and harmful fungi.
• When harmful fungi invade the body, they can be difficult to kill, as they
can survive in the environment and re-infect the person trying to get
better.

41. Types of Fungal Infection
• Athlete‘s Foot: Athlete's foot fungal infection.
• Ringworm: Ringworm fungal infection.
• Jock Itch: Jock itch fungal infection.
• Yeast Infection: Yeast fungal infection.
• Onychomycosis: fungal infection of the nail.

42. Symptoms of Fungal Infections
• Symptoms of fungal infections can range from mild to very serious.
• The exact symptoms depend on the type of fungus that has caused
the infection.
• Some common symptoms include:
Asthma-like symptoms , Fatigue , Headache ,
Muscle aches or joint pain, Night sweats, Weight loss ,
Chest pain , Itchy or scaly skin

43. Causes of fungal infection

44. Fungi that cause infections

45. • Athlete’s foot is caused by,
- Trichophyton rubrum.
- T interdigitale.
- Epidermophyton floccosum.
• Ringworm infection is caused by,
- Tinea corporis.
- Majocchi's granuloma.
- Tinea imbricata.

46. • Jock itch fungal infection is caused by,
-Tinea cruris
- Tinea pedis
• Yeast fungal infection is caused by,
-Candida albicans

47. Prevention and control
• How can fungal infections be prevented
1. keep your skin clean and dry, particularly the folds of your skin.
2. wash your hands often, especially after touching animals or other
people.
3. avoid using other people's towels and other personal care products.
4. wear shoes in locker rooms, community showers, and swimming
pools.

48. Control
1. You are more likely to get a fungal infection if you have a weakened
immune system or take antibiotics.
2. Fungi can be difficult to kill. For skin and nail infections, you can
apply medicine directly to the infected area.
3. Oral antifungal medicines are also available for serious infections.
4. Like hydrogen peroxide, rubbing alcohol can help kill off the fungus
that's on the surface level of the skin. You can apply it directly to
the affected area.

49. antifungal medicines
1. clotrimazole (Canesten)
2. econazole
3. Miconazole
4. terbinafine (Lamisil)
5. fluconazole (Diflucan)
6. ketoconazole (Daktarin)
7. nystatin (Nystan)
8. amphotericin.
9. Itraconazole.etc.,.

50. 4.Parasitic infection
• Parasites are organisms that live off other organisms, or hosts, to
survive. Some parasites don't noticeably affect their hosts. Others
grow, reproduce, or invade organ systems that make their hosts sick,
resulting in a parasitic infection.
• Parasitic infections can be spread in a number of ways. For example,
protozoa and helminths can be spread through contaminated water,
food, waste, soil, and blood. Some can be passed through sexual
contact. Some parasites are spread by insects that act as a vector, or
carrier, of the disease.

51. Parasites

52. Examples of parasitic infections
• E. vermicularis, or pinworm.
• Trypanosoma cruzi, the cause of Chagas disease.
• Echinococcosis, another tapeworm, passed through dogs and sheep.
• Cysticercosis, or tapeworm.
• Toxocariasis, or roundworm.
• Trichomoniasis, a sexually transmitted infection.
• Amebiasis.

53. Symptoms
• The signs and symptoms of infections caused by a parasite vary
depending on the organism that’s residing in your body.
• Some of the most common signs of a parasitic infection include:
• Stomach cramps and pain
• Nausea or vomiting
• Dehydration

54. • Digestive problems including unexplained
constipation,
• diarrhoea or persistent gas
• Skin issues such as rashes,
• Weight loss
• Swollen lymph nodes

56. Prevention
•Practice safe sex, using a condom.
•Wash your hands regularly, especially after
handling uncooked food or feces.
•Cook food to its recommended internal
temperature.
•Drink clean water, including bottled water
when you're traveling.

57. Treatment
•doctor will prescribe medications
that destroy parasites, such as
albendazole (Albenza) and
mebendazole (Emverm). These
medications are generally taken
once to treat the infection.

58. •Treatment for parasites include creams and
ointments used to eliminate them and treat
the symptoms.
• Common drug classes used to treat
parasitic infection are antiparasitics,
nitroimidazole antibiotics, and pyrethroids.

59. •Metronidazole, or alternatively
tinidazole, is the basis of therapy for
giardiasis, trichomoniasis, and
amebiasis.

60. Reference
• https://www.healthdirect.gov.au/bacterial-infections
• https://www.medicalnewstoday.com/articles/bacterial-infection-symptoms
• https://www.onhealth.com/content/1/bacterial_infections
• https://www.narayanahealth.org/blog/viral-infections-types-treatment-
and-prevention/
• https://www.onhealth.com/content/1/viral_infections
• https://www.medicalnewstoday.com/articles/317970
• https://www.healthline.com/health/parasitic-
infections#:~:text=What%20is%20a%20parasitic%20infection,resulting%20i
n%20a%20parasitic%20infection.