Medical Technology, Science, Technology and Society

2. INFECTIOUS DISEASES
The emergence and re-emergence
of infectious diseases in the 21st
century pose new threat challenges
to humans regardless of age, sex,
lifestyle, ethnic background, and
socio-economic status.

3. PERIODS/PHASES IN THE COURSE OF INFECTIONS
1. Incubation period
2. Prodromal period
3. Period of illness
4. Period of decline
5. Convalescent period

4. INCUBATION PERIOD
• First appearance of signs and symptoms
PRODROMAL PERIOD
• Starts to feel sick but does not have severe infection
PERIOD OF ILLNESS
• Experiences the typical symptoms of the disease
PERIOD OF DECLINE
• The immune system is able to control the replication of
the pathogen.
CONVALESCENT PERIOD
• The body is already starting to recover and regain its
strength

5. EPIDEMIOLOGY
is the study of the distribution, patterns,
causes, effects, and control of disease in a
population.
POINT PREVALENCE
refers to the number of cases of a particular
infectious diseases in a particular population at
a given time.
INCIDENCE
pertains to the number of new cases of
infectious disease in a given period of time.

6. The distribution of infectious diseases in a
population at a given time and location can be
described by:
• SPORADIC
• ENDEMIC
• EPIDEMIC
• PANDEMIC

7. SPORADIC DISEASE
a disease that is normally absent in a
population and occurs as single, isolated
cases.
ENDEMIC DISEASE
a disease that occurs frequently in a
specific geographical location or
population group.

8. EPIDEMIC DISEASE
widespread occurrence of a disease that
affects many individuals in a particular
location at a given time.
PANDEMIC DISEASE
several countries are affected by an
epidemic disease is considered as a
pandemic.

9. INFECTIONS OF
HUMAN BODY
TISSUES AND
ORGANS

10. INFECTIOUS DISEASES OF THE SKIN
IMPETIGO
• caused by Staphylococcus aureus, Streptococcus
pyogenes.
• red sores and yellow brown crusts.
ERYSIPELAS
• “Holy Fire”
• Acute bacterial infection caused by S. pyogenes.
• High fevers, chills, fatigue, headaches, vomiting.

11. CELLULITIS
• Caused by normal skin flora, group A Streptococcus &
Staphylococcus.
• Red, hot, and tender skin.
FOLLICULITIS
• Infection of the hair follicle.
• Deep folliculitis is known as Furuncle or boil.
• Multiple infected hair follicles is called Carbuncle.
• Caused by S. aureus and S. pyogenes.

12. FUNGAL INFECTIONS:
ATHLETE’S FOOT (tinea pedis)
• peeling, redness, itching, burning, blisters, and
sores in the feet.
JOCK ITCH (tinea cruris)
• itching, redness, flaking, peeling, cracking of
skin in the genitals, inner thighs, groin, and
buttocks.
RINGWORM (tinea corporis)
• appears as red, circular, and scaly skin.

13. INFECTIOUS
DISEASES OF THE
EYES

14. CONJUNCTIVITIS
• inflammation of the conjunctiva.
• “pink eye”
• Caused by adenovirus or cold virus, and
bacteria (Chlamydia, staphylococci, and
streptococci).
• Redness, inflammation of the eyelids,
discharge, and sensitivity to light.

15. KERATITIS
• Caused by S. aureus and Pseudomonas
aeruginosa.
• Common in contact lens users.
• Pain in the eyes, light sensitivity,
production of tears and discharge, and
blurred vision.

16. CHORIORETINITIS
• caused by toxoplasmosis and
cytomegalovirus
• characterized by floating black spots,
blurry vision, pain, redness in the eye,
sensitivity to light, and excessive
tearing.

17. INFECTIOUS DISEASE OF THE RESPIRATORY SYSTEM
UPPER RESPIRATORY ORGANS
• NOSE
• PHARYNX
• SINUSES
• LARYNX

18. UPPER RESPIRATORY INFECTIONS
• TONSILITIS
• PHARYNGITIS
• LARYNGITIS
• SINUSITIS

19. LOWER RESPIRATORY ORGANS
• TRACHEA
• BRONCHI
• LUNGS

20. Lower respiratory tract infections
• Bronchitis
• Pneumonia

21. INFECTIOUS DISEASES OF THE ORAL CAVITY
• Gingivitis
• Blisters and sores caused by the herpes
simplex virus
• Oral cancer caused by human
papillomavirus
• Odontogenic infections include dental
caries, periodontitis (common chronic
bacterial infection) , pericoronitis and
oral thrush caused by Candida species

22. INFECTIOUS DISEASES OF THE
GASTROINTESTINAL TRACT
GASTROENTERITIS
• infection of the stomach and intestines
• Caused by bacteria, viruses, parasites
• Clostridia species causes excessive
salivation, vomiting, diarrhea, strainig,
abdominal pain

23. VIRAL GASTROENTERITIS
• “Stomach Flu”
• caused by rotavirus,
adenovirus,calicivirus, astrovirus
• Vomiting and diarrhea (with or without
blood)
• Roundworms
common cause of parasitic gastroenteritis

24. INFECTIOUS DISEASES OF THE GENITAL TRACT
• SALPINGITIS
inflammation of the fallopian tubes caused by
chlamydia and gonorrhea.
• ENDOMETRIOSIS
infection in the tissue lining of the uterus.
• OVARIAN INFECTION caused by chlamydia,
gonorrhea, ureaplasma and mycoplama
bacteria.

25. • VAGINAL YEAST INFECTIONS
are caused by fungi called Candida, which are
normal flora. Other causes for vaginitis include
bacterial vaginosis, Trichomonas vaginalis,
chlamydia, genital herpes and the human
papillomavirus.
• Female lower reproductive tract infections like
VAGINITIS (infection of the vagina),
VULVOVAGINITIS (infection of the vagina and
vulva) and CERVICITIS (infection of the cervix)

26. • ORCHITIS (inflammation of the testicles)
caused by bacteria, E. coli,
stapyhlococcus, etc
• URETHRITIS (infection of the urethra)
caused by chlamydia or mycoplasma
bacteria
• inflammation of the vas deferens

27. INFECTIOUS DISEASES OF THE CIRCULATORY
SYSTEM
• Infections of the blood (SEPSIS), blood vessels
(VASCULITIS) and heart
• ENDOCARDITIS-infection of the lining of the
heart chambers and heart valves caused by
bacteria
• MYOCARDITIS-infection of the myocardium
caused by virus

28. PERICARDITIS
is the infection of the pericardium caused by
viruses (coxsackeivirus), bacteria
(pneumococcus), fungi (histoplasmosis).
• Microbial infection of blood and blood vessels
is called SEPTICEMIA (blood poisoning) caused
by Streptococcus pyogenes.

29. INFECTIOUS DISEASES OF THE NERVOUS
SYSTEM
MENINGITIS
caused by pneumococci, meningococci,
enterovirus
ENCEPHALITIS caused by herpes simplex
virus, mycoplasma, candidiasis

30. MENINGOCEPHALITIS
caused by protozoa (Toxoplasma
gondii), herpes simplex virus, etc
MYELITIS
is the inflmmation of the spinal cord
caused by virus, bacteria, fungi.

31. Severe Acute Respiratory Syndrome
(SARS)
• Is a viral infection in humans that is caused by
the SARS coronavirus (SARS-coV)
• This virus is contagious and can be spread by
respiratory droplets
• Symptoms is fever. Early symptoms are flu-like,
fever, chills and body aches
• Treatment such as ribavirin and corticosteroids

32. ACQUIRED IMMUNODEFICIENCY
SYNDROME
• A condition characterized by a weakened
immune system caused by the human
immunodeficiency virus (HIV).
• It slowly invades immune system and uses the
genetic material of CD4+ T cells to reproduce
itself and then eventually kills the CD4+ T cells.
• HIV can be seen in various body fluids that
include blood, semen, vaginal fluid, breast milk,
etc. that contains blood.

33. • Symptoms are decrease in the number of
CD4+ T cells, immune system’s respond
is weak, common symptoms include
diarrhea, Pneumonia, fatigue, weight
loss etc.
• People with AIDS are prone to
opportunistic infections because of
weakened immune system.

34. HIV found in blood, semen, vaginal
fluid of a HIV-positive person can be
transmitted through unprotected
sexual intercourse, mother-to-child,
blood transfusion and accidental
needle stick injuries.

35. DEVELOPMENTAL STAGES OF AIDS
• PRIMARY STAGE-short, flu-like illness.
Occurs 1 to 6 weeks after infection with
no symptoms. An infected person can
infect other people.
• SECONDARY STAGE-can last for an
average of ten years. Generally free from
symptoms.

36. • THIRD STAGE-symptoms are mild
although the immune system is
deteriorating. There is the emergence of
opportunistic infections and cancers.
• FOURTH STAGE-immune system
weakens and the illness become more
severe, leading to an AIDS diagnosis

37. PREVENTION
the most important way to change risky
behavior is via health education. Studies
shown the positive impact of education
and health literacy on safe sex behavior.

38. ZOONOTIC INFLUENZA
• caused by influenza virus that has three
broad categories: influenza A, B, C.
• Avian flu and swine flu, which are new
to human infection are caused by a
subtype of influenza A
• This type of infection is known as
ZOONOSIS, which means that the
disease is transmitted from animals to
humans.

39. AVIAN FLU
• Known as bird flu
infectious disease of birds caused
by type A strains of the influenza virus.
• Symptoms include fever, pneumonia,
diarrhea, and encephalopathy.
• Highly pathogenic to humans are types
H5N1, H7N3, H7N7, H7N9, and H9N2.

40. • H5N1 causes epizootics (animal
outbreaks) in Asia, Europe, Middle East,
and Africa.
• This type of virus also has ANTIGENIC
SHIFT, which is a swapping of genetic
material with human influenza viruses.
• This mutation can lead to the formation
of a highly pathogenic virus that can be
transmitted from person to person.

41. SWINE INFLUENZA
• Also known as pig, influenza, swine
flu, or pig flu.
• symptoms: chills, fever, sore throat,
muscle pains, severe headache,
coughing and weakness.
• Swine flu is caused by influenza A
subtypes H1N1, H1N2, H2N3, H3N1 and
H3N2.

42. DIAGNOSIS
Avian flu
• can be diagnosed by viral culture,
PCR assay for avian influenza A
(H5N1) RNA, immunofluorescence for
antigen with the use of H5
monoclonal antibody, and four-old
rise in H5-specific antibody.

43. Swine flu
• can be diagnosed by the viral
culture of respiratory secretions
such as sputum or nasal/throat
secretions. PCR is a specific test
for the genetic material of the virus.

44. TREATMENT
• Patients are given antiviral
medicines: oseltamivir (Tami-flu),
which are in capsules; and
zanamivir (Relenza), which is an
inhalant.

45. PREVENTION
• Avoid prolonged exposure or direct
contact to the avian and swine flu
viruses. Swine-to-human
transmission can be minimized
thru the vaccination of swine.
Humans can also receive the swine
flu vaccine.

46. HEPA B
• It is can infectious illness caused by the
Hepatitis B (HBV) that infects the liver of
humans.
• HBV replicates in the liver but later
spreads to the bloodstream, which is
why it can be transmitted through blood
transfusion.

47. SIGNS AND SYMPTOMS
• Initial infection with the hepa B is
called “acute infection” and may be
asymptomatic.
• Symptoms include liver inflammation,
vomiting, and jaundice.
• Hepa B infection may last less than six
months because the immune system is
able to destroy the virus.

48. CHRONIC HEPA B infection
• lasts for six months or longer because
the immune system cannot destroy the
virus, which can lead to serious illness
such as CIRRHOSIS and LIVER
CANCER. It may be undetected for years
until the person develops liver disease.

49. TRANSMISSION
• It can be transmitted thru exposure to
infectious blood or body fluids that
contain blood, unprotected sexual
intercourse, blood transfusion, vertical
transmission during childbirth; and
reuse of contaminated needles and
syringes.

50. PREVENTION
• The best method to prevent hepa B is
thru vaccination. The hepa B vaccine is
prepared from the inactivated (dead)
hepa B virus, which is attacked by the
immune system. Inside the body, the
vaccine that contains the HBV is
considered as a foreign body by the
immune system so the body starts
producing antibodies to kill the virus.

51. INFECTIOUS MONONUCLEOSIS
• Infectious mononucleosis is a viral
disease caused by the Epstein-barr
Virus (EBV).
• Also known as Pfeiffer’s disease,
Filatov’s disease, glandular fever, and
“kissing disease”.
• It is common among adolescents and
young adults.

52. MODES OF TRANSMISSION
• This infection is spread via saliva and
has an incubation period of 4-7
weeks.
• Healthy people may have the EBV in
their saliva, and may spread it to
others over a period of weeks. They
are carriers, or primary reservoirs, for
person-to-person transmission

53. PATHOPHYSIOLOGY
• Early primary infection occurs in oral
epithelial cells before it spreads to B
lymphocytes. Then the infected
lymphocytes circulate to the liver,
spleen, and peripheral lymph nodes. The
immune system of the infected person
will produce antibodies against EBV.
• Latent infection of EBV is characterized
by replication in oral epithelial cells and
release of the virus into saliva.

54. SIGNS AND SYMPTOMS
• The first three days of exposure to
EBV are characterized by initial
symptoms that include loss of
appetite, malaise, chills, and
fatigue.
• This is followed by intense
symptoms that include fever and
severe sore throat.

55. DIAGNOSTIC CITERIA
• According to Hoagland (1960):
“Classical clinical triad”: fever,
pharyngitis, and adenopathy. This
is confirmed by a positive serologic
test, and the presence of at least
50% lymphocytes and 10% atypical
lumphocytes.

56. DIAGNOSTIC TESTS
• Blood tests for the diagnosis of
infectious mononucleosis include CBC
and mononucleosis test.
• Monospot and heterophil tests are
screening methods.
• The liver is conducted to determine if the
EBV has affected the liver.

57. TREATMENT
• Treatment includes self-care and
rest.
• To soothe the sore throat, gargling
with salt water or taking throat
lozenges can be done.
• For other symptoms like fever,
acetaminophen or ibuprofen may
be taken.