Communicable diseases and Nursing Care and Intervention

Communicable disease
•    An illness caused by an infectious agent or toxic product and is transmitted by direct or indirect contact between the reservoir host and susceptible individual.
Chain of infection
The infectious disease process is defined as the interaction between the pathogenic microorganism, the environment, and the host. The process may be thought of as a circular chain with six links. The following story illustrates the chain.

Chain of infection

- The infectious disease process is defined as the interaction between the pathogenic microorganism, the environment, and the host. The process may be thought of as a circular chain with six links. The following story illustrates the chain.
Communicable disease: illness caused by an infectious agent. By transmission of that agent to a susceptible host (person or animal).
Infectivity: is the ability of an organism to spread rapidly from one host to another.
Invasiveness: is the ability of the agent to spread within the host.
Virulence: is the ability to produce severe disease.
Dosage: refers to the fact that multiple organisms invading the host are more apt to overwhelm host defenses, whereas small number of the same organisms is frequently tolerated without diseases actually occurring.
Host: human or animal in which an infectious agent may enter and cause disease.

Agent: an organism (virus, fungus, protozoa, bacteria…..) capable of producing infection in a susceptible host.
Vaccine: immunization agents injected in the body to stimulate the body to produce antibodies against organisms.
Epidemic: the occurrence of diseases in a region clearly in excess of expected incidence.
Endemic spread: disease that is constantly present in the community due to availability of ecological factors that are needed for the existence and maintenance of infection.
Pandemic: a worldwide outbreak of an epidemic disease.
Nosocomial infection: in the episodic setting an infection that is not present or incubating at the time of admission (hospital infection).
Incubation period: time beginning with host exposure to an infectious agent and continuing until the organism multiplies to sufficient numbers to produce a host reaction and clinical symptoms.

Nosocomial infection: (hospital infection)

It is the infection that may be acquired by a patient attending any medical center or unit including hospital.
Mode of transmission:
1. Direct infection:
- Direct patient-patient, visitor-patient infection.
- personnel-patient infection.
2. Indirect infection:
- Through hospital articles when not properly sterilized, e.g. dressing, instruments, syringes and needles.
- Unsanitary hospital and surrounding environment.
1. Natural active immunity: immunity is acquired through exposure to infection in endemic areas stimulates the development of immunity for many diseases. E.g. in case of measles, chicken pox, rubella, mumps and diphtheria.
2. Natural passive immunity: maternal acquired immunity. The pregnant provides the fetus with antibodies in the last weeks of pregnancy. It is temporary and lasts about 6 months. Also infants who are breast feed will have lower incidence of respiratory diseases than formula-feed infants.
3. Acquired active immunity: resistance to diseases from vaccination against common diseases to stimulate the body to produce antibodies against organisms. E.g. diphtheria and polio.
4. Acquired passive immunity (seroprophylaxis): immunity is acquired at a person by immunoglobulin (ready – made antibodies). It persists for a short period 2-3 weeks or some months. E.g. serum globulin for infectious hepatitis.

Live vaccine: made of live virus as small pox.
Live attenuated vaccine: virulent organisms are so treated to become attenuated and a virulent, but antigenic e.g. BCG vaccine, measles, mumps, rubella vaccine, yellow fever vaccine and sabin polio vaccine (oral vaccine).
Killed vaccine: vaccines made of killed organisms which are in activated by heat or chemicals still remain antigenic as cholera vaccine, Pertussis vaccine.
Polysaccharide vaccines: prepared from capsule of the organism as meningococcal vaccine.
They stimulate formation of antitoxic humeral immunity as diphtheria toxoid and tetanus toxoid.

Transmission of communicable diseases:
CHN should understand how the disease is transmitted in order to prevent it.
Agent factors:
4 agent characteristics influence the transmission and severity of disease:
- Infectivity - virulence - invasiveness - dosage
Each agent factor can exist independently of the others.
Host factors:
- Age - heredity - resistance to infection (diet, overall well-being of the host) can affect the immune system's ability to control the organism. E.g. mumps is tolerated well by young children than middle age adults.
Environmental factors:
Social factors: cultural habits or economic constraints can affect the disease transmission. Education plays an important role in improving unhealthy diet, and unhealthy habits.
Physical factors: overcrowding, inadequate sewage can pollute the environment causing diseases.
1.Airborne transmission:
The organism is in the air from sneezing or coughing.
2. Fecal/oral transmission:
Direct: hands or objects are contaminated with the organism from human or animal feces and then placed in the mouth.
Indirect: ingestion of food or water that has been contaminated with fecal particles containing the organism, as when workers in restaurants are not cleaning their hands after using the toilet.

Common communicable diseases

•    Diphtheria
•    Pertussis
•    Tetanus
•    Poliomyelitis
•    Measles
•    Mumps
•    Rubella
•    Tuberculosis
•    Meningitis
•    Chickenpox

Immunization Schedule


Contraindication to vaccination:

Permanent contraindication:
1.Severe allergy to a vaccine.
2. Encephalopathy.
Temporary contraindication:
3.Severe illness.
4.Recent recipient of blood products
DPT: 1. any acute febrile illness.
2. Exposure to disease
3. Any severe allergic reaction.
4. Residual seizure attacks.
Measles: 1. hypersensitivity to eggs.
Rubella: 1. pregnant women.
MMR: 1. recently acquired passive immunity.
2. Blood transfusion of immune serum globulin within last 6 weeks because the presence of passive immunity prevent formation of antibodies to the vaccine.
3. Pregnancy: potential risk to fetus from Rubella vaccine.
OPV: 1. Gastroenteritis because it may interfere with colonization of he virus in the intestines which is important for the immunity response to occur.

Vaccines recommended for specific life situation:

1.Hospitals and other health care personnel: hepatitis B, influenza, rabies.
2. Animal handlers: rabies.
3. Travelers: measles, rubella, yellow fever, hepatitis B, meningitis, typhoid, cholera and rabies.

Communicable Diseases

1. Chicken pox (varicella):
Agent: varicella zoster virus.
Period of infectivity: one day before, up to 7 days after appearance of the rash.
Incubation period: 2-3 weeks.
Mode of transmission:
1. Droplet infection.
2. Contaminated objects with fluids of vesicles.
Clinical picture:
1) Prodromal period: mild fever, malaise, headache. These symptoms are for 24 hours, sometimes it so mild to pass unnoticed.
2) Skin eruption: maculopapules appear first then change to vesicles in few hours. Vesicles are superficial and in few days dry up to form crust which fall in around one week. Secondary infection and pustulation of vesicles may sometimes occur.
Secondary infection and pustulation of vesicles (staphylococcal), and encephalitis.

Chickenpox Skin Lesions
Simultaneous appearance of different stages of lesions
Appearance of the skin
Lesions in the mouth

2. Diphtheria:
Agent: Corynebacterium diphtheriae (diphtheria bacillus).
Incubation period: 2-7 days.
Mode of transmission:
1. Direct droplet infection.
2. using soiled articles
Clinical picture:
1) Low grade fever, malaise, sore throat.
2) Formation of gray membrane on the mucosa of throat.
3) Toxemia: caused by exotoxin secreted by the local organisms, heart muscle and CNS are involved.
1. Muscles paralysis.
2. Bronchopneumonia
3. Measles:
Agent: measles virus.
Mode of transmission:
1. Direct contact with droplets of infected persons,
2. Airborne infection.
3. Using articles freshly soiled with nose and throat secretions.
Incubation period: 10 - 20 days.
Clinical picture:
1) Catarrhal stage (prodromal stage): 4 days from onset of disease till the rash appears high fever, anorexia, headache, sneezing, sore throat, nasal obstruction and dry irritating cough. Koplik's spots (small, irregular red spots with a minute white center first seen on buccal mucosa 2 days before rash and disappear with the appearance of the rash.
2) Eruption stage: rash usually appears 4 days after the onset of disease first on the face and behind the ears, then the trunk and limbs. It lasts for about 5 days and fades in the order of appearance.
Complications: otitis media, bronchitis, sinusitis, and diarrheal diseases.
Koplik spots

4. Mumps:
Agent: mumps virus.
Period of infectivity: from the last day of incubation period and throughout the disease until swelling of salivary glands disappears.
Incubation period: 18 days on the average.
Mode of transmission:
1.Direct droplet infection.
2.Using saliva-soiled articles.
3.In utero infection is a potential risk.

Clinical picture:
1) Prodromal stage: fever, headache, malaise and anorexia for 24 hours, followed by earache that is aggravated by chewing.
2) Parotitis: by third day, parotid gland enlarges and reaches maximum size in 1 to 3 days accompanied by pain and tenderness.
1. Sterility in male.
2. Unfavorable outcome of pregnancy from inutero infection including congenital anomalies when expectant mother is infected during the first months of pregnancy.

5. Pertussis: (Whooping cough)
Agent: Bordetella Pertussis (the Pertussis bacillus).
Incubation period: 7 – 10 days.
Mode of transmission:
1. Direct droplet infection.
2. Airborne infection and freshly soiled articles.
Clinical picture:
1) Catarrhal stage (1-2 weeks): begins with symptoms of upper respiratory tract infection as sneezing, low grade fever and dry irritating cough.
2) Paroxysmal stage: cough most often occurs at night and consists of short, rapid coughs followed by expectoration of clear mucous and vomiting.
1. Pneumonia.
2. Otitis media.
3. Umbilical hernia.
4. Convulsions in infants.
5. Hemorrhage: nose and conjunctiva.

6. Poliomyelitis:
Agent: poliovirus. Three types of this virus
Type I: most frequent cause of paralysis.
Type II: least frequently associated with paralysis.
Type III: second most frequently associated with paralysis.
Incubation period: usually 7-14 days.
Mode of transmission:
1. Direct contact with persons with apparent or inapparant active infection (droplet infection).
2. Hand – to – mouth infection
3. Food born infection: food is contaminated with poliovirus (handling, flies, water and dust).

Clinical picture:
1) Abortive poliomyelitis: the majority of cases are abortive. Infection is benign with mild systematic manifestations for one or two days only, then clears without being suspected for polio and may sometimes be so mild to pass unnoticed and gives immunity.

2) Involvement of CNS: the CNS is involved in a small proportion of cases, few days after subsidence of abortive stage, and takes two forms:
Non paralytic poliomyelitis: fever, headache, nausea, vomiting, abdominal pain and signs of meningeal irritation (pain and stiffness of neck, back and limbs).
Outcomes: a) Clearance of symptoms and the case acquires immunity.
b) The case passes into paralytic stage.
Paralytic poliomyelitis: paralysis usually appears around 7-10 days from onset of disease. Symptoms include fever, headache, irritability and different paralytic manifestations according to part of CNS involved.
1. Respiratory: pneumonia, pulmonary edema.
2. Cardiovascular: myocarditis.
3. Urinary: infection.
7. Rubella (German measles)
Agent: rubella virus.
Incubation period: about 18 days.
Mode of transmission:
1. Direct droplet infection.
2. Airborne infection.
3. Using freshly soiled articles.
4. Inutero infection causing congenital rubella.
Clinical picture:
1) Prodromal period: short period of less than one day, with moderate fever, mild respiratory catarrh and malaise.
2) Rash: appears within 24 hours and lasts for 3days. It is maculopapular (like that of measles)
Are rare (bronchitis, arthritis).
Inutero infection:
- During the 1st trimester, causes abortion or congenital malformations (deaf, mental retardation, heart disease, cleft palate and others).
- Inutero infection later in pregnancy: still birth or congenital rubella.

8. Tetanus:
Is a form of wound infection characterized by acute intoxication that involves the nervous system.
Agent: tetanospasmin (tetanus bacillus).
Incubation period: 4 - 21 days.
Mode of transmission:
1.Injury in any polluted place: the wound gets contaminated with tetanus spores in the soil.
High risks are:
- Injuries in the street, farm, or park.
- Minor injuries by broken glass.
- Occupational injuries in the field or workplace.
- War injuries.
2. Neonatal infection: when the umbilical stump is contaminated with tetanus spores on cutting the cord with contaminated instruments, or dressing the stump with contaminated material, causing ''tetanus neonaturum".
3. Surgical tetanus: it is postoperative tetanus, a form of hospital infection which may occur through:
- Using improper sterilized catgut (prepared from sheep gut).
- Using contaminated, unsterilized instruments and dressing.
- Contamination of surgical wound with tetanus spores-containing dust from unclean hospital environment.
Clinical picture:
1) Due to toxemia which involves the nervous system: the exotoxin affects the motor nerve endings, and anterior horn cells of spinal cord and brain stem.
2) Cases show severe tonic spasm of muscles:
- First appears around the wound.
- Neck muscles are affected, giving stiffness of neck and other parts of the body.

Prevention of communicable diseases can be attained at three levels: primary, secondary, and tertiary.
1.Primary prevention seeks to reduce the incidence of disease through:
-Health promotion and public education regarding immunization, method of spread of communicable diseases, proper preparation and handling of food and water supplies.
-Also advice parents in case of out break to confine child to the home to avoid exposure.
2. Secondary prevention targets the reduction of disease prevalence and disease morbidity through early diagnosis and treatment.
- Report disease to local health department.
- Skin test for T.B.
- Identify close contacts that may require prophylactic treatment.
3. Tertiary Prevention works to reduce complications & disabilities related to disease through treatment and mental and physical rehabilitation. E.g. chemoprophylaxis.

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