INTRODUCTION TO INFECTIONS

INFECTION

Invasion and multiplication of microorganisms

in body tissues, especially that causing local

cellular injury due to competitive

metabolism, toxins, intracellular replication,

or antigen-antibody response

Overview of Plasmodium's life cycle

DIFFERENT TYPES OF INFECTIONS

Airborne infection:  one that is contracted

by inhalation of microorganisms or spores

suspended in air on water droplets or dust

particles.

Droplet infection:  infection due to

inhalation of respiratory pathogens suspended

on liquid particles exhaled by someone already

infected.

DIFFERENT TYPES OF INFECTIONS

Endogenous infection:  that due to

reactivation of organisms present in a dormant

focus, as occurs in tuberculosis.

Opportunistic infection:  infection by an

organism that does not ordinarily cause

disease but becomes pathogenic under certain

circumstances (e.g., impaired immune

responses).

AIRBORNE INFECTION

RESPIRATORY TRACT INFECTION

Infection involving the respiratory tracts

Classified as an upper respiratory tract or

a lower respiratory tract infection 

Lower respiratory infections, such as pneumonia,

tend to be far more serious conditions than

upper respiratory infections, such as the

common cold.

URTI

Infections in the nose, sinuses, pharynx, and larynx

Typical infections of the upper respiratory tract include:

Tonsillitis

Pharyngitis

Sinusitis

Otitis media

Influenza

Common cold

SYMPTOMS OF URTIS

Cough

Sore throat

Runny nose

Nasal congestion

Headache

Low grade fever

Sneezing

LRTI

Lower respiratory tract infections are generally

more serious than upper respiratory infections

LRIs are the leading cause of death among

all infectious diseases

The two most common LRIs:

Bronchitis and pneumonia

PNEUMONIA

Pneumonia is an inflammatory condition of

the lung

Especially affecting the microscopic air sacs

(alveoli)

Associated with fever, chest symptoms, and a

lack of air space (consolidation) on a chest X-ray

CAUSES

Microbial infections:

Bacteria, 

Viruses

Fungi

Parasites

Other causes

TYPICAL SYMPTOMS

Cough

Chest pain

Fever

Difficulty breathing

DIAGNOSIS

X-rays

Sputum examination

CLASSIFICATION

Community-acquired

Aspiration

Hospital-acquired

Ventilator-associated pneumonia

CAUSATIVE AGENTS

Viruses and bacteria (most common)

Fungi and parasites (less common)

Mixed infections with both viruses and bacteria:

Up to 45% of infections in children

15% of infections in adults

Causative agent is not isolated in approximately

half of cases

INFLUENZA

Influenza affects both the upper and lower

respiratory tracts

More dangerous strains such as  H5N1 tend

to bind to receptors deep in the lungs

MANAGEMENT

Antibiotics

Antiviral