some of the Respiratory infections with their causative agents, transmission mode treatment, prevention , control

1. RESPIRATORY INFECTIONS
DEVIPRIYA PV
M PHARM

2. CONTENTS
 Communicable diseases: Causative agents,
mode of transmission and prevention of
Respiratory infections:
1. Chicken pox
2. Measles
3. Influenza.
4. Diphtheria
5. Whooping cough
6. Tuberculosis.

3. COMMUNICABLE DISEASES
 The diseases which are transmitted from one person to
another or from a reservoir to a susceptible host.
 Eg:Tuberculosis.
 Communicable period is the time required for the transmission
of infectious agent from the reservoir to a susceptible host .
 It can be controlled by:
 Improvement of personal hygiene.
 Improvement of social hygiene.
 Awareness about health.
 Awareness about diseases

4.  Types of communicable diseases:
(1)Respiratory infections:
 Eg:Tuberculosis
(2)Intestinal infection
 Eg: Hepatitis.
(3)Arthropod borne infections
 Eg: Plague.
(4)Surface infections:
 Eg: Leprosy
(5)Sexually transmitted diseases:
 Eg: AIDS

5. Mode of transmission of communicable diseases:
(1)Direct contact:
 Exposure to infected body fluids such as blood or saliva
(2)Vectors/ Reservoirs:
 Germs are spread by an animal or insect, usually through a
bite
(3)Food andWater:
 Food and water can become contaminated with pathogenic
microorganisms and people get sick when they eat or drink
them
(4)Airborne:
 Pathogens are spread through the air. eg: coughing, sneezing
(5)Indirect contact:
 Pathogens remain on surfaces that were in contact with an
infected person

6. Mode of transmission

8. CHICKEN POX
 The causative agent of chicken pox is a virus called Varicella
Zoster(V-Z virus) or Human (alpha) herpes virus 3.
Mode of transmission:
 Transmitted from person to person by Droplet infection
 The virus enters the respiratory tract.
 Sometimes the virus spreads by contamination from the
discharge from ruptured lesions of the skin
Clinical features:
 Fever, appearance of the rash in the form of crops on the trunk,
face and limbs.

9.  Within 24 hours the lesions become pustular (filled with
pus).
 The pustules dry up in a few days to form scabs.
Incubation period:
 14-16 days.
Prevention:
 Varicella Zoster immunoglobulin (VZ Ig) given within 72
hours in a dose of 1.25 to 5 ml intramuscularly.
 VZ Ig immunoglobulin is particularly useful in new born.
 A live attenuated vaccine has been launched.
 The side effects include mild local reaction or rash.

10.  There is a controversy about the use of chicken pox
vaccine because:
 Vaccination prevents the disease in childhood but later
on it the child is exposed to the virus the disease is more
severe as compared to mild early childhood chicken pox.
 The live attenuated virus may establish itself as latent
infection which may produce Zoster or chicken pox like
disease at a later age.
 The natural disease is mild and passes away if
complications are prevented and reliable immunity is
produced

11. MEASLES (RUBEOLA)
 Most people suffer from measles in childhood.
 One attack confers a high degree of immunity.
 A mother who has had disease the disease confers passive
immunity on her infant for the first six months.
 The onset of measles is acute with nasal catarrh, sneezing,
redness o the eyes, a short cough, hoarseness of voice.
 Koplik’s spots (narrow zones of inflammation) can be seen inside
the cheek around the opening of parotid gland.
 These signs and symptoms persists for 3 to 4 days.
 Then a typical maculopapular rash develops first on the face and
gradually extends all over the body.

12.  The rash subsides within 5 to 7 days leaving a brownish
pigmentation
Causative agent:
 The causative agent is an RNA paramyxovirus commonly
called Rubeola virus.
Mode of transmission:
 Transmission occurs directly from person to person
mainly by droplet infection, and droplet nuclei from four
days before onset of rash until five days thereafter.
 The portal of entry is the respiratory tract or rarely
conjunctiva.
Incubation period:
 Incubation period is commonly 10 days from exposure of
fever and 14 days to appearance of rash.

13. Prevention:
 Achieve an immunization rate of over 95%
 Ongoing immunization against the disease through successive
generations of children
Measles vaccination:
 The prevention is done by active immunization.
 For this live attenuated, tissue culture freeze dried vaccine is
used.
 A single dose of 0.5 ml of the reconstituted vaccine is
administered subcutaneously in children of 9-12 months.
 The vaccine and its diluting fluid are stored at 4-8°C.
 Unvaccinated children can be passively immunised by giving
human immunoglobulins within 3-4 days of exposure.
 The dose of immunoglobulin recommended by WHO is 0.25 ml
per kg of the body weight.
 After 8-12 weeks, give active immunization by measles vaccine

14. INFLUENZA
 Influenza is an acute respiratory tract infection.
 The disease starts with sudden malaise, headache, backache,
pain in the limbs, anorexia, nausea and sometimes vomiting.
 Fever to 39°C remits for 2-3 days, with chills and rigours.
 There may be harsh unproductive cough.
Incubation period:
 Incubation period is one to two days.
Causative agent:
 Influenza viruses A, B & C belonging to the family
orthomyxoviridae.

15.  Type A is responsible for the pandemics.
Mode of transmission:
 Spread from person to person by droplet infection or
droplet nuclei.
 The portal of entry of the virus is the respiratory tract.
Prevention:
 Prophylactic immunization is the presently best
approach.
Vaccine:
 Killed chick embryo vaccine conventionally formulated in
aqueous or saline suspension, is given subcutaneously in
a single dose of 0.5 ml to above 3 years of age and 0.25
ml to children between 6 months to 3 years of age.

16.  In persons with no immunoglobulin experience, two
doses of the vaccine separated by an interval of 3 to 4
weeks are administered.
 Antibodies starts appearing within one week and reach
to the maximum by two weeks.
 The vaccine is 70-90% effective for 3-6 months period.
 Common reactions are inflammation, fever and egg
allergy since the virus is grown on eggs.
Treatment:
 Antiviral drugs like Amantadine or Rimantidine in a dose
of 100mg is given twice a day for 3-5 days.
 These compounds are useful for the treatment and
prophylaxis of influenza.

17. HUMAN SWINE FLU
 The disease is caused by Influenza A virus of strain H1 and N1.
 It is an acute highly communicable viral febrile respiratory
infection.
 The source of infection is an infected person.
 The patients have flu like sign and symptoms and can be put
under three categories:
(1)Suspected case: is a person having history of contact with a
patient within seven days
(2)Probable case: is a person having history of contact or visit to an
infected area with flu like symptoms.

18. (3)Confirmed case: is a person having history of contact,
symptoms of influenza and one test positive out of the
following three:
(1)Real time PCR
(2)Viral culture
(3)Fourfold rise in influenza A (H1N1) virus
specific neutralizing antibodies.
 Transmission of the disease takes place by droplet
infection.
 The incubation period is 18-72 hours.
 Drug treatment is given for confirmed cases.
 Oseltamivir tablets 75 mg twice a day for 5 days.
 For prophylaxis 75 mg once

19. DIPHTHERIA
 Diphtheria is an acute infectious disease affecting most
commonly the upper respiratory tract.
 Anterior, nasal, facial and laryngeal are the three major
clinical types.
 Skin, conjunctiva, vulva and other parts of the body may also
be involved.
Causative agent:
 Caused by strains of Corynebacterium diptheriae.
 The organism is non- motile gram positive bacillus which
produces powerful exotoxin.

20. Mode of transmission:
 Mainly spread by droplet infection.
 Sometimes, transmitted directly from infected cutaneous
lesions.
 Transmission of the disease by objects(such as toys, cups,
thermometers etc) infected by nasopharyngeal secretions
is also possible
Portal of entry:
 Respiratory tract in most of the cases.
 Other routes are breech in the skin, eye, genitalia and
middle ear
Incubation period: 2 to 4 days.
Prevention:
 Prevention can be done by early detection of cases and
carriers, and their treatment.

21.  Active immunization with combined vaccine called DPT
vaccine, containing toxoid of diphtheria and tetanus and
killed organisms of pertussis is an effective control.
 DPT is given intramuscularly in three doses , each consists
of 0.5 ml of vaccine at the age of ½ months, 2 ½ months
and 3 ½ months.
 After this, a first booster dose of 0.5 ml of DPT is given
intramuscularly at the age of 18 months to two years.
 The second booster dose of DT vaccine (containing
diphtheria and tetanus toxoids) 0.5 ml intramuscularly at
the age of 3 ½ years.
Treatment:
 For specific treatment, Diphtheria antitoxin prepared in
horse serum is given in a dose of 10,000 to 30,000 units
intramuscularly or 40,000 to 10,000 units intravenously in 2
divided doses at an interval of 2 hours

22. WHOOPING COUGH (PERTUSSIS)
 Whooping cough occurs at all ages but approximately 90%
of the cases are children under 5 years of age.
 It is an acute infection of respiratory tract.
Causative agent:
 Bordetella pertussis
 In small number of cases the agent responsible for the
disease is Bordetella parapertussis
Mode of transmission:
 Spread mainly by droplet infection and direct contact.
 The bacilli spread into the air while sneezing, coughing or
taking to the patient.
 The portal of entry is respiratory tract

23. Incubation period:
 7 to 14 days
Clinical features:
 The organism multiplies on the surface epithelium of
respiratory tract and produces inflammation and necrosis
of mucosa.
 The inflamed mucosa is further infected by other types of
bacteria.
 Paroxysmal attacks of cough are more severe in night.
 During this paroxysms the face become cyanosed and the
tongue may be injured.
 The complications of the disease are bronchitis and
bronchopneumonia

24. Prevention:
 Early diagnosis isolation, treatment and disinfection of
nasal or throat discharges.
 Infants and young children should be kept away from
cases.
 The drug treatment consist of Erythromycin 50 mg/kg
body weight in 4 divided doss for 10 days.
 Other useful drugs are Ampicillin and Cotrimoxazole.
 These drugs are useful in controlling the secondary
infections
Active immunization:
 DPT vaccine

25. TUBERCULOSIS
 Tuberculosis is a specific infectious disease primarily
affecting the lungs(pulmonary tuberculosis ).
 It can also affect intestine, meninges of the brain, bones,
joints, lymph glands, skin and other tissues of the body.
Causative agent:
 Mycobacterium tuberculosis.
 It is an acid fast bacillus which can be ingested by
phagocytes and is resistant to intracellular killing.
 3 types- human type, bovine type, atypical or anonymous
mycobacteria.

26. Mode of transmission:
 Transmitted by droplet infection and droplet nuclei,
produced by the sputum of the sputum positive patients
with pulmonaryTB.
 Coughing generates large number of droplets with viable
organism.
 TB is not spread by the fomites(dishes or other articles)
used by the patients.
Prevention ofTuberculosis:
 Control programmes, ie, National Tuberculosis Programme
(NTP) and the DistrictTuberculosis Programme (DTP).
(1) Raising the resistance of the population to the disease by:
(a) Good social conditions including satisfactory housing and
an adequate diet

27. (b) BCG (Bacillus calmette guerin) vaccination:
 Intra dermal injection of 0.05 ml of the vaccine, just after birth
or 0.1 ml with the first dose of DPT vaccine.
 The preferred site of injection is the upper part of the left arm
near the insertion of deltoid muscle.
 BCG vaccine consists of freeze dried live attenuated bovine
strain of tubercle bacilli.
 The vaccine is stored at 4 to 8°C.
 The vaccine should be used within 4 hours after reconstitution.
(2) Reduction of the human infection by:
(a)Detection and isolation of maximum number of cases.
 It is required in cases with persistent cough, continuous fever,
chest pain and haemoptysis.

28.  This can be done by sputum smear examination, mass
miniature radiography (MMR)and tuberculin test
 Sputum smear examination by direct microscopy is the best
method of choice.
 MMR is costly and not reliable.
 Tuberculin test is performed by giving 0.1 ml of Tuberculin
antigen intradermally.The readings are taken after 72 hours.
(b) Chemoprophylaxis:
 Done by giving INH alone for one year or INH plus
ethambutol for 9 months
(3) Elimination of tuberculosis infection in milk:
 Pasteurisation kills the tubercle bacilli by heat while
preserving the nutritive components of the milk.

29. Chemotherapy of tuberculosis:
 Done in case of activeTB for cure.
 The first line drugs have high efficiency and low toxicity and
it includes Isoniazid (H), Rifampicin(R), Pyrazinamide(Z),
Ethambutol(E) and Streptomycin(S)
 The second line drugs have low efficiency, high toxicity and
are useful only in selected patients .
 It includes Thiacetazone (Tzn), Paraaminosalicylic acid (PAS),
Ethionamide(Etm), Cycloserine (Cyr), Kanamycin (Kmc),
Amikacin (AM), Capreomycin (Cpr), Ciprofloxacin, Ofloxacin,
Clarithromycin, Azithromycin and Rifabutin.
 The longer duration treatment is replaced by more effective,
less toxic and short duration treatment called “short course
chemotherpy”(SCC)

30. First line drugs and their doses
Name of drug Daily dose in mg/kg Three times per week dose
Isoniazid (H) 5 10
Rifampicin (R) 10 10
Pyrazinamide (Z) 25 35
Ethambutol (E) 15 30
Streptomycin (S) 15 15

31.  For different categories ofTB different regimens are used.
Category I :
 This category includes
:new untreated sputum smear positive cases,
:seriously ill sputum smear negative pulmonary cases
:seriously ill extra pulmonaryTB cases
Intensive phase:
 Four drugs HRZ+E or S are given daily or thrice weekly for 2
months.
 The phase can be extended for one month in case the smear
has not become negative
Continuation phase:
 Two drugs HR daily/ thrice weekly for 4 months or HE daily
for 6 months are given

32. Category II :
 The cases include smear positive, treatment failure, relapse
and interrupted treatment.
 These patients have resistant bacilli and are at increased risk
of developing multidrug resistantTB (MDR-TB)
Intensive phase:
 All 5 first line drugs are given daily for 2 months followed by
4 drugs (HRZE) for next month.
 If at the end of third month, sputum is still positive the 4
drugs are continued for another month
Continuation phase:
 3 drugs (HRE) are given for 5 months either daily or thrice
weekly

33.  Category III:
 In this category new smear negative pulmonary TB or less
severe extrapulmonaryTB cases are included
Intensive phase:
 Three drugs (HRE) are given for 2 months
Continuation phase:
 Two drugs (HR) are given daily or thrice weekly for 4 months or
HE daily for 6 months.
Category IV :
 It include multi drug resistant cases.
 The patients remained or have become smear positive after
completing full treatment.
 For H resistance cases RZE are given for one year and for H+R
resistance cases ZE+ S/ Etm+ Cipro are used.
 The regimen is selected according to the features of individual
patients

34.  AntiTB drugs HRZE are safe to the foetus.
 E is avoided in early pregnancy
 All antiTB drugs are compatible with breast feeding.
Direct ObservedTreatment Short course(DOTS) chemotherapy
 TB patients tend to discontinue treatment after some time &
this lead to resistance to bacilli for antiTB drugs.
 To combat this , a new strategy has formulated in which the
patient swallows the drug in front of health worker during
intensive and continuation phase.
 The patient is asked to bring the empty multi blister pack to
ensure intake (since the most important part in TB treatment is
adequate and complete drug intake)

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