EPIDEMIOLOGY AND CONTROL OF DIPHTHERIA AND TETANUS Dr. Awatif Alam

Epidemiology: Identification Infectious agent Occurrence Reservoir Mode of transmission I.P. Period of communicability Susceptibility and resistance

Methods of Control: A.Preventive measures: Vaccination Public education Others B.Control of patients, contacts and environment: C.Epidemic Measures: Prompt reporting IG for outbreaks Priorities if short of vaccine

DIPHTHERIA Epidemiology: Identification: an acute bacterial disease of tonsils, pharynx, largnx, nose, occasionally of other mucous membranes or skin and sometimes the conjunctiva or genitalia. The characteristics lesion, caused by liberation of a specific cytotoxin secondary to proliferation of bacteria at a focus of infection. Patches of an adherent grayish membrane with surrounding inflammation. The focus is usually the throat, spreading to the fauces, pharynx and larynx.

Infectious Agent: Coryndbacterium diphtheria of biotype: Gravis, Mitis, Intermedius Reservoir: Man Carriers: Do exist but are less infective than cases. Mode of transmission: Pts. * or carriers (direct droplet). Soiled articles (indirect). Raw milk (served as a vehicle). Occurrence: * Geography: World wide. A disease of colder months ( temperate zones). Prevalence depends on: - the extent of immunization - population density.

Age: - Unimmunized children < 15 yrs., - often found among adults ( where immunization was neglected). - Unusual among infants. Sex: No sex difference. I.P.: Usually 2-5 days. Period of Communicability: - Variable (until virulent bacilli disappear from discharges and lesions (usually 2 wks or less and seldom > 4 wks). ** Rarely chronic carriers may shed organisms for 6/12 or >.

Susceptibility and Resistance: - Infants born to immune mothers are relatively * immune for up to 6/12. - Recovery from clinical attacks are (in the majority) followed by lasting immunity. - Immunity acquired through inapp.infectn. - In tropics, cutaneous dipth. can pass unnoticed and induces significant immunity. - In U.S.A. > 40% of adults lack protective levels of circulating antitoxin.

Clinical Manifestations - The S & S depend upon: Site of infection, Immunization status, escape of toxin to ciculation. - Diphtheria is classified clinically on the basis of the anatomic location of the initial infection, and the dipth. Membrane: 1-Nasal Diphtheria: initially resemble mild common cold with rhinorrhea and paucity of systemic symptoms.

2- Tonsillar and pharyngeal diphtherias: (insidious and more severe) Accompanying symptoms& signs: anorexia, malaise, low grade fever and pharyngitis. Within 1-2 days a memb. appears of various extent (depending on the immune status of the host). Cervical lymphadenitis is variable. “Bull Neck”: edema of soft tissue of neck. 3- Laryngeal diphtheria:- downwards extension of memb. from pharynx, Occasionally, only laryn. Involvement is present (pts. toxicity less prominent).

4- Cutaneous, vulvovaginal, conjunctival and aural dipheria also occur. Complications:- 1. Respiratory Obstruction leading to death (young children with laryng. or tracheal diph. due to occlusion of airway by dipht. memb. + edema of neck). 2. Myocarditis may follow both severe and mild cases of dipht. esp. among pts. with extensive local lesions who experienced delay in administn. of antitoxin (2nd week). 3. Neurologic Complications: - Usually appear after a variable latent period, - predominantly bilateral motor > sensory , - usually resolves completely.

Control and Prevention Preventive Measures: 1- Active immunizatn. with diph. toxoid, including an adequate program to maintain immunity. Triple Antigen DPT. Schedules: a- < 6-7 yrs: 4 doses of DPT Ist 3 doses to be given at 4-8 wks. Intervals beginning when infant is 6-8 wks. Old (2 and 4 and 6 months in S.A.) The 4th dose given 1 yr after the 3rd dose. A 5th dose, usually given at school entry.1

b. For persons > 7 yrs. , : for previously unimm b. For persons > 7 yrs., : for previously unimm. Individual, a primary series of 3 doses of tetanus and dipth. Toxoids (adult type, Td) is given. The Ist 2 doses at 4-8 wks. Intervals, the 3rd dose 6/m – 1 yr. After 2nd dose. c. Active protectn. Should be maintained by administering a dose of “Td every 10 yrs.” thereafter, (esp. for persons who are at higher risk to pt. exposure e.g. health workers). 2 . Educational measures: to inform the public and esp. parents of young children of the hazards of diptheria and the imp. of immunization.

Control of pt., contacts and immediate environ.:- - Report to local health authority. - Isolation : Strict for pharyn. diph. Contact isolatn. for cutan. diph. {Until 2, cultures from both throat and nose (or skin lesions) taken at least 24 hrs. apart, and not less than 24 hrs. after cessatn. Of antimicrob. therapy, fail to show dipht. bacilli.} Or when culture is impractical, isolatn. may be ended after 14 days of appropriate antibiotic Rx. Concurrent disinfectn.: of all articles in contact with pts.

Management of case:- 1 . DAT and antibiotics to be started immediately without waiting for lab. results. 2. Rest and observation, to cover the period of potential cardiac damage and paralysis , 3. Avoid limbs deformity + ensure joint mobility. 4. Tracheostomy and artificial respiration . Management of Contacts: 1. For those who are previously immunised , adminst . a booster dose (Td). 2. For those not imm. they should be cultured and given DAT followed by immun. later on.

Tetanus Infectious Agent: Clostridium tetani Identification: An acute disease induced by an exotoxin of the tetanus bacillus, which grows anaerobically at the site of an injury. The disease is characterised by painful ms. contractions, primarily of the masseter and neck ms., secondarily of trunk ms.

Clinical Picture: ( common early S & S ) - lock jaw and muscular pain, - Abdominal rigidity, - Generalised spasms , ( frequently induced by sensory stimuli) typical features of the tetanic spasm are the facial expression known as “risus sardonicus”. Note : Dysphagia is an uncommon but important early symptom.

Period of onset: The time bet. the Ist symptom and the appearance of reflex ms. spasm. ( A typical tetanus pt. is apprehensive and alert. All voluntary ms. are hypertonic esp. on face, neck, spine and abd. wall). Complications: “ Tetanus is not simply a disorder of motor function. The autonomic N.S. is also rendered unstable by the action of the toxin.” - Death occurs mainly due to either asphyxia or autonomic instability (e.g. sudden changes in pulse rate, bl.P., and cardiac output). - Serious cardiac arrythmias, excessive sweating and fever may occur.

I.P.: Usually 5-10 days (36 hrs and several months have been reported). Reservoir:- Intestine of animals, in which the organism is a harmless normal inhabitant. Soil contaminated with animal and rarely human feces. Mode of Transmission: - Tetanus spores introduced into the body, usually through a puncture wound contaminated with soil … etc. - The *umbilical wound when (unhyg.) dressed is the main portal of entry in “T. neonatorum.” - The presence of necrotic tissues, foreign bodies, poor local bl. supply, favours growth of the anaerobic pathogen.

Period of Comm.:- - Not directly transmitted from person to person. Susceptibility and Resistance:- - Suscept. is general. - Active immunity is induced by tetanus toxoid and persists for at least 10 yrs. after full immunizatn. Recovery from tetanus may not result in immunity. Second attack can occur.

Methods of Control: Preventive Measures: 1. Active Immunization with tetanus toxoid every 10 yrs. - Protections after the initial basic series has been completed - single booster doses induce high levels of immunity. eg. DPT Usually used for series imm. program. DT For children < 7 yrs. Td For adults. Tetanus toxoid is recommended for universal use regardless of age, esp. for people at greater than usual risk of traumatic injury (workers, policeman and people in contact with domestic animals).

2. Education on: - the necessity of complete immunization with T. Toxoid, - the kind of injury particularly liable to be complicated by tetanus, the potential need after injury for passive and *active phrophylaxis.

Control of pt., contacts and immediate environment: Report to local health authority. No isolatn. Immunizatn. Of contacts: None Investigatn. of contacts and source of infectn.: Specific Rx: human tetanus immunoglobulin* (TIG) i.m. follow a wound. If TIG not available, give tetanus antitoxin* in a single large i.v. dose + parentral penicillin in large doses for 10-14 days.

Specific Treatment b. Wound should be debrided widely. c. Maintain an adequate airway. d.Employ sedatn. (as indicated) or ms. relaxant. e.Active imm. should be initiated concurrently with therapy. 6.Destruction of environmental spores: - esp. in operating theaters. - Special air-flow equipment and filtered ventilation. - Reduce airborne particles. Surgical instruments and dressing sterilizatn (use of autoclaves). Disinfectn. e.g. formaldehyde.