By
Dr. Sabry Ahmed Salem
Prof. of community medicine
Environ mental health &
occupational medicine
COMMUNICABLE DISEASES
II- Air- Borne Diseases
1- Bacterial
II- Viral
1. Diphtheria.
1. Mumps.
2. Whooping cough.
2. Chicken pox.
3. Streptococcal infections.
3. Measles.
4. Meningococcal meningitis or 4. German measles.
cerebrospinal fever.
5. Influenza.
5. Pulmonary. T.B.
6. Common cold.
6. Vincent’s angina.
7. Viral meningitis.
8. Viral pneumonia.
III- Rickettsial
1. Q fever.
2. Typhus.
Primary atypical
3. Spotted fever
pneumonia (PAP)
V- Mycotic:
IV- Chlamydial
1. Actinomycosis.
Psittacosis
2. Blastomycosis.
Psittacosis:
3. Coccidioidoinycosis.
4. Histoplasmosis.
WHOOPING COUGH
Causative agent:
Bordetella pertusstis (Pertussis bacillus)
Reservoir:
Cases: bacteria in respiratory. discharge
Communicability
If no antibiotics: begins one week after
exposure to3w after onset of cough.
Mode of transmission:
1. Direct droplet infection (cough spray).
2. Droplet ruclei (Air-borne infection).
3. Contaminated articles and fomites.
Incubation period:
7-10 days
Clinical picture
1. Catarrh:
2. Whoops, cough and vomiting:
3. Convalescence:
4. Complications.
a. to hernia, rectal prolapse,
b. Secondary infection as otitis media,
c. Malnutrition
Diagnosis:
1. Clinically: by typical paroxysms.
2. Laboratory: by culture of nasopharyngeal swab.
Susceptibility:
 begins at birth “no mother-foetus immunity.
 Highest incidence around school age.
 Almost all become immune by the age of 15 y.
exposed adults may be rarely affected.
Prevention:
By specific protection (immunization and
chemo prophylaxis).
1- Immunization:
a) Active
.DPT: for children below 4 ys.
 Pertussis vaccine: can be given before 4
months of life during out breaks.
b- Seroprophylaxis:
Pertussis Ig may be given to exposed young infants.
2- Chemoprophylaxis
Erythromycin or Ampicallin for 10 days to contact
infants and young adults.
Control:
a- Cases:
b- Contacts:
a. Exclusion of the case (No further contact).
b. Surveillance.
c. Prophylaxis.
i. If immunized:
vaccines before 4yrs.
ii. If not immunized:
(chemoprophylaxis) Antibiotics
Pertussis in school.
 Exclusion of cases for period of infectivity.
 Susceptible family contacts are excluded for 2
ws, after last exposure.
 Susceptible school contacts are put under
surveillance for 2 weeks to exclude any case
showing resp. catarrh.
Causative agent:
Streptococcus pyogenes (group A betahaemolytic streptococci
Reservoir:
-Cases.
-Carriers
organisms in throat and nose
(incub. & convalescent) discharge.
Mode of transmission
1. Direct droplet inf. (The most important).
2. Droplet nuclei and dust.
3. Contaminated articles and fomites.
4. Milk-borne infection.
Incubation period:
1-3 days.
Clinical picture:
1. High fever.
2. Sore throat.
3. Cervical lymphadenopathy.
4. Enlarged tonsile follicular spots of exudates or
pseudomembrane in severe cases which can be
removed easily.
5. Pharyngitis.
6. Complications - suppurative
- non suppurative
Prevention:
1- Sanitation of environment :
2- Health education.
3- Chemoprophylaxis
Control:
a- Cases:
b- Contacts:
c- Epidemic measures :
Prevention of sore throat in school : by
1. Good ventilation, spacing, healthy behaviour, food and
milk sanitation.
2. Examination of personnels and early case finding
(isolation treatment and return after cure).
SCARLET FEVER
Causative agent:
Streptococcus (group A, haemolytic)
Reservoir
- Cases.
- Carriers.
Clinical picture:
Sore throat ( pharyngitis).
Toxaemia with skin rash, appears on the 2nd day
of disease as generalized punctuate erythema.
Circumoral pallor.
Straw berry tongue.
Diagnosis:
1- Clinically: Symptoms and signs.
2- Laboratory:
 Throat swab and culture.
 Schultz- Charlton reaction (Skin test).
 Antistrepolysin O: Rising titre.
Susceptibility:
By Dick test (like schick test of diphtheria), and if:
+ ve is susceptible.
-ve is not susceptible (immune)
MENINGITIS
1- Purulent: Caused by
- Meningococcus:
cerebrospinal fever.
- Streptococcus.
- Staphylococcus.
- Other pyogenic bacteria.
2- Aseptic: caused by
-Viruses.
- Leptospirae.
3- Granulomatous: Caused by
-T.B.
- Fungi.
-Syphilis ($).
MENINGOCOCCAL MENINGNITIS
“cerebrospinal fever”
Causative agent:
Meningococcus,
Reservoir:
Cases.
Carriers (all types): organism in nasopharyngeal
discharge.
Mode of transmission:
1.Direct droplet infection: more common through contact
with cases & carriers.
2.Droplet nuclei and articles are rare because the
organism dies rapidly outside the body.
Incubation period:
2-7 days.
Clinical picture: sudden onset of
- Fever.
- Headache.
- Cattarh.
- Neck rigidity.
- Head retraction.
•+ve kernig’s sign.
•+ve brodzinski’s sign.
•Complications:
hydrocephalus, optic neuritis, ocular nerve
palsy, nerve deafness, arthritis, and other severe
complications.
Diagnosis :
1. Clinical picture.
2. Laboratory.
 Blood culture shows meningococi.
 CSF exam shows Pus cells.
3. Nasopharyngeal swab.
Prevention:
1- General
2- Specific protection
a. Chemoprophylaxis: by rifampicin 600 mg daily for 3 days.
b. Vaccination: by polysaccharide vaccine.
 Prepared from polysaccharide of meningococcus
capsule (type A and C).
 Highly effective in immunity process and carrier state.
 Given as a single dose of 0.5 ml sc.
 Duration of immunity up to 3 years.
 Given to high – risk groups in areas exposed to
epidemics (e.g. military groups and old diabetics).
Control:
a- Cases:
b- Contacts
c- Epidemic measures: (during outbreaks)
For closed communities and high-risk groups:
- Ventilation and spacing.
- Surveillance, to detect and treat cases.
- Chemoprophyaxis: by Rifampicin 600 mg once
daily/5 days.
- Vaccination of high-risk groups.
Tuberculosis T.B
T.B. is classified into
- Pulmonary T.B. (90% of total T.B)
- Extrapulmonary T.B (10%)
Causative agent: by the tubercle
(mycobacterium tuberculosis) of 5 types:
1- Human type:
2- Bovine type
3- Avian type:
4- Murine type:
5- Reptilian type:
bacilli
Pulmonary T.B
Causative agent
* T.B bacilli (Myocbacterium tuberculosis).
I) Human type: nearly , all cases of P.T.B.
II) Bovine type: 2-4% of pulmonary. T. B
Reservoir:
a. Man: Open cases T.B in resp. discharges.
b. Cattle: Tuberculous cattle (cough spray).
Transmission of T.B:
I- Human type
1- Direct droplet infection: the most common
2- Airborne infection by
a. Droplet nuclei.
b. Dust with dried sputum.
3- Contaminated articles and fomites.
II- Bovine type:
Inhalation of the tubercle bacilli in the cough spray of
diseased cattles. Infection is usually occupational in farmers
and agricultural workers.
Incubation period
A bout 4 weeks.
Clinical picture:
1- Constitutional:
-Night fever.
- Loss of weight.
- Night sweat.
- Anorexia.
-Fatigability.
2- Local (Plumonary)
-Cough with sputum.
- Dyspnea.
-Haemopytsis.
- Pleuritic pain.
Diagnosis:
1. Clinical: Night fever, night sweats, anorexia, loss
of weight, prolonged cough and haemoptysis are
suggestive.
2. Tuberculin test
if +ve
If – ve
previous infection or immunity.
No. T.B.
1. Chest x-ray: for screening of suspected cases.
2. Sputum exam.: bacteriological detection of T.B.
bacilli in the sputum.
Bacterial sputum examination
is the only
conclusive diagnosis of pulmonary T.B.
Sputum examination:
a. Stained smear: -ve result does not exclude T.B
due to number of bacilli may not be so big in the
sputum to show in smear.
b.Culture: is more diagnostic.
c. Animal inoculation: rare
III- Factors predisposing to reinfection
Re-activation of disease is due to :
1. Malnutrition.
2. Debilitating diseases e.g. diabetes, peptic ulcer and
thyroid disease.
3. Stress and fatigue.
4. Prolonged corticosteroid therapy.
5. Industrial exposure to silica dust (silicosis).
Immunity in T.B:
a. Due to primary infection: immunity persisting so
long the T.B focus exists in the body.
b. Infection or premuntion immunity developed
later.
c. Protection against exogenous infection:
immunization.
Tuberculin test: Skin test based on delayed
hypersensitivity of any person previously infected with
T.B. bacilli develop cell-mediated hypersensitivity.
Procedure: by manttoux test.
0.1 ml PPD (purified protein Derivative)
containing 5TU (tuberculin units)., injected ID; skin of
fore-arm just below the elbow joint.
Reading: The diameter of indurated area is measured
in mm after 48-72 hrs.
-ve : no reaction or induration less than 5 mm.
+ve: induration 10 mm or more.
Value
If –ve : the person is free .
If +ve: it means presence of T.B infection or BCG vaccination
Application of tuberculin test:
1. Survey studies: to show prevalence of infection.
2. Evaluation of preventive programs.
3. Case-finding: the test is not diagnostic but help in
case finding (screening).
4. Exclusion of pulmonary T.B. when test, is- ve.
5. Before immunization of adults above 16 ys. BCG is
given to non-reactors (-ve).
Epidemiological indices
Used to measure the magnitude of pulmonary T.B
problem and classified into: mortality, morbidity and infection
indices.
A- Mortality indices:
1. Mortality Rate: Number of deaths from pulmonary T.B
per 100.000 population in a certain locality and year.
2. Age and sex-specific M.R.
3. Case-fatality rate: Number of deaths per 100 Number of
cases.
B- Morbidity indicies:
1. Incidence rate: Number of reported new cases of pulmonary
.T.B per 100 population in a certain locality and year.
2. Prevatence rate: Number of all cases (sputum +ve) of
pulmonary T.B in a survey study per 100 individials
examined.
Prevention of T.B.:
1. Community development.
2. Sanitation of environment.
3. Health education of public.
4. Health promotion: adequate nourishment, avoid fatigue and
stress.
5. Specific prevention: by vaccination and chemoprophylaxis.
A- Vaccination: by BCG (Bacillus calmette &
Guerin) live – attenuated bacilli.
Action: vaccine  local focus of infection
at site of injection stimulation of immune system.
-ve tuberculin after 3 months of
vaccination becomes +ve
No risk of infection from the liveattenuated Bacilli
Dose & administration: 0.1 ml ID on the
outer surface of upper arm near the shoulder.
B- Chemoprophylaxis
INH
(isonicotinic acid hydrazide) is given in
proper dose for one year to tuberculin + ve cases,
young children < 5 ys, recent tuberculin convertors
and those with prolonged corticosteroid therapy and
diabetics when necessary.
Control of pulmonary tuberculosis
1- Case finding:
a- Suggestive x-ray examination:
b- Confirmatory sputum examination:
2- Measures for cases:
-Notification.
-Isolation
-Disinfection
-Periodic X-ray and sputum
examination
-Release:
-Follow up:
-Rehabilitation:.
-Social services
3- Measures for contacts :
1-Tuberculin testing.
If – ve give BCG
If + ve: * x-ray for case finding.
* Chemoprophylaxis for high-risk.
2- Follow up especially when cases are treated at home.
3- Health education.
MEASLES
Causative agent: Measles virus, delicate and
perishes within hours outside the body.
Reservoir: Cases (no carriers), nose and throat
secretions contain the virus
Communicability period: Throughout the disease
(about 9 days): 4 days catarrh and 5 days
skin less infective rash.
Mode of transmission:
1. Direct droplet infection.
2. Contaminated articles and fomites.
3. Droplet-nuclei (air-borne). Branny scales of rash
are not infective and not have viruses.
Incubation period
About 10 days (14 days until rash appears).
Clinical picture
1. Coryza, cough and conjunctivitis.
2. Fever:
3. Koplik’s spots:
4. Skin rash: 4 days after onset of disease where fever
drops and rash ends by branny desquamation.
5. Complications:
a. bronchitis, pneumonia & bronchopneumonia.
b. Gastroenteritis may lead to malnutrition.
c. Otitis media, purulent conjunctivitis.
d. Encephalitis, rare.
Diagnosis:
Clinically by – Coryza, cough and conjunctivitis.
- Fever 38.5oC.
- Koplik’s spots.
- Skin rash ends by branny desquamation.
Prevention:
a- Active immunization
by measles vaccine (live-attenuated vaccine).
95 % effective single dose, life-long immunity and it is given to.
1. Children: compulsory in Egypt to all infants 9-12 months of
age.
2. Susceptible children of any age.
3. Adults: if not vaccinated or infected by measles before but
not during pregnancy.
4. During measles epidemics: Seroprophylaxis then
vaccination.
Seroprophylaxis:
Immunoglobulins given to susceptible contacts of any
age IM.
Control:
Cases:
b- Contacts:
c- Measles in school: No need for school closure.
Exposed susceptibles are given seroprophylaxis and
excluded from school for 14 days from last exposure
and then examined, if there is catarrh exclusion for 4
days more to confirm measles or not.
National elimination of measles:
Broad lines of the program:
1. Achieving high immunization coverage
2. Strong surveillance system.
3. Aggressive outbreak control.
INFLUENZA
Causative agent:
Influenza viruses: of 3 antigenic types
- Type A epidemics and pandemics
- Type B local outbreaks.
- Type C sporadic cases
Reservoir:
Human cases: (Clinical and inapparent).
Animals:
e.g. pigs and horses.
Mode of transmission:
1. Direct droplet.
2. Articles & fomites.
3. Droplet nuclei (air –borne).
Incubation period: 1-3 days
Clinical pictures:
1. Sudden onset of fever (40oC), chills, headache,
prostration and myalgia.
2. Nasal catarrh, sore throat and cough.
3. Cure within 2-7 days (if not complicated).
4. Complications:
a. Acute sinusitis, otitis media, bronchitis and
pneumonia due to 2ry bacterial Infection.
b. Viral pneumonia (very rare).
c. Pericarditis, myocarditis and thrombophlebits.
Susceptibility:
The individual may get more than one attack
due to many types and subtypes of the virus
and the ability of virus to change its genotype
at any time.
Infection causes type specific immunity.
Infection may occur at any time of the year but
outbreaks usually occur in winter and early
spring.
School age shows higher incidence.
Prevention: by vaccination
1. Killed vaccine:
Control:
a. Cases: notification, isolation, dis-infection and
treatment.
b.Contacts: surveillance to spot new cases.
ARI MANAGEMENT
ARI may be
1. Upper respiratory tract infection: Mainly viral
2. Lower Respiratory tract infection: Mainly bacterial
a. Strep pneunoniae
b. H. Influenzae
c. Staph. Aureus.
Standard case management of ARI (SCM)
Diagnosis depends mainly on:
1. Respiratory rate (RR).
2. Chest indrawing (retraction).
3. Cough.
So if infant < 2 months with RR > 60 /m
Or
2-11 m with RR > 50/m
Or
1-5 y with RR > 40 /m
The infant is considered ill ( ++RR)
SCM: depends on the following bases (i.e based on):
1.  RR + lower chest indrawing indicates severe pneumonia
to be hospitalized.
2.  RR without chest indrawing indicates severe pneumonia
to be hospitalized.
Indrawing chest: Pneumonia oral antibiotics and
Home care
3- Normal RR without chest indrawing+ cough + cold – No
antibiotic.
4- Infant < 2m with cough, difficult breathing refer to the
hospital but, if referral is not easy give antibiotic
Lab. Diagnosis: by lung puncture and culture of the lung
aspirate.
Strategy of ARI management program
(WHO):
1.Preparation of ARI clinics in PHC centers and
units.
2.Personnel training of PHC staff.
3.Management of screened cases.
a. Nursing
b. Feeding
c. Chemotherapy
d. Inhalation of oxygen
4- Health education of mothers by personal approach
and mass media, the message comprising:
a. Breast feeding encouragement.
b. Seeking medical care, early.
c. Management of cases:
Avian Influenza
“Bird Flu”
Causative Agent: There are 3 types of influenza
virus.
Type A: Infect man and birds.
Types B & C ; Infect man only Virus A of birds has
more than 16 antigenic types of antigen H & 9 forms of
Ag. N, but H5N1 have been isolated in outbreaks of
birds and some cases of man in different countries.
Mode of transmission between birds and man
Excreta of infected birds leads to pollution of air and
soil causing inhalation of the virus.
1. Contaminated objects by inhalation
2. Falls (excreta) of flying birds.
3. Markets and shops of birds.
4. May be rodents “ Mechanical spread”.
Clinical picture in birds:
Minor; e.g Coarse feather, low egg production.
Major: Severe infectious out breaks causes 100%
death of birds within 48 hrs.
Transmission to man
Inhalation of the virus by direct contact or handling the
infected birds.
Up till now there is no transmission from man to man,
unless gene mutation of the virus takes place.
Clinical picture in man:
Either:
1.Influenza- like picture (fever, cough, sore
throat, myalgia, bone ache….). OR.
2. Severe pneumonia which may lead to death.
International spread of disease between
countries:
1. Trade of living birds.
2. Migrating birds.
Prevention & control:
1. No vaccine is available for man.
2. Antiviral drugs e.g. tamiflu is used to control the
disease in man.
3. Preventive measures include.
a. Measures for person in direct contact with
birds:
* Hand washing. * Protective clothes.
* Head cover
* Glasses
* Stocks and gloves.
* Nose covering
* Vaccination with annual vaccine against influenza.
a.Measures for the public:
* Proper cooking.
* Avoiding contact with dead birds.
* Sanitary land fill of dead birds.
* Birds places cleaning.
* Protective measures during dealing with birds.