Tetanus

Instructional Objectives: At the end of the lecture the student would be able to: 1-Define the main clinical characteristics of Tetanus and Anthrax. 2-Point out the occurrence of the diseases. 3-List the causative agent, mode of transmission, incubation period, and period of communicability of Tetanus and Anthrax. 4-List the main preventive measures of Tetanus and Anthrax. 5-Describe the control measures of Tetanus and Anthrax.

Tetanus is an acute disease induced by an exotoxin of the tetanus bacillus, which grows anaerobically at the site of an injury. *Characterized by : 1.Painful muscular contractions Masseter and neck Trunk muscles muscles *It can cause abdominal rigidity

2.Generlized spasms frequently induced by sensory stimuli. 3.Typical features are position of opisthotonus and risus sardonicus expression.

*Case fatality rate is 10–90% according to: Age (high among infants and elderly), Incubation period, and Availability of experienced intensive care. *Infections agent: Clostridium Tetani.

Occurrence : *World wide sporadic disease. *More common in agriculture regions and underdeveloped areas. *Addiction on parental drugs can result in individual cases. Reservoir: 1-Intestine of horses and other animals. 2-humans(the MO is normal harmless inhabitant). 3-Soil contaminated with animal and human feces.

Mode of transmission: 1.Tetanus spores usually introduced through contaminated wound, puncture or through lacerations ,burns, and trivial or unnoticed wounds. 2.Through injectable contaminated drugs. 3.Occasionaly follows surgical procedures including circumcisions. (Necrotic tissues favors the growth of the pathogen) Incubation periods: Usually (3-21) days. However its range is (1day – several months) . The shorter period means the worst prognosis.

Period of communicability : No person to person transmission . Susceptibility and resistance : Susceptibility is general. Active immunity is by tetanus toxoid which persist for (10 years) after full immunization. Transient passive immunity by tetanus immunoglobulin (TIG) or tetanus antitoxin (equine origin ). Infants of actively immunized mothers acquire passive immunity against neonatal tetanus. Recovery from tetanus not result immunity, thus a second attack can occur so Primary immunization after recovery is indicated.

Preventive Measures: 1.Educate public about necessity of complete immunization and risk of puncture wounds contamination that need active or passive prophylaxis. 2.Universal active immunization with adsorbed tetanus toxoid protection for at least (10 years). (TT, DTP, DT)

3.Prophylaxis in wound management through:- Careful assessment of wound state of contamination. Immunization status of patient. Proper use of tetanus toxiod and /or tetanus immunoglobulin . Wound cleaning. Surgical debridement and antibiotics use.

Summary guide to tetanus prophylaxis Other wounds Toxoid IG Minor wound Toxoid IG History of tetanus immunization Yes Yes (250IU of TIG IM) Yes No Uncertain or <3 No* No *(yes if>5y since last dose) No* No )*yes if>10y since last dose) 3 or more

If both Tetanus toxoid and immunoglobulin are indicated, they must be given: concurrently, at different sites, and separate syringes must be used.

Control Measures: 1.Report to local health authority. 2.Investigation of contacts and source of infection (case investigation to determine circumstances of injury). 3.Specific treatment:- TIG (3000-6000IU) intramuscularly.( if not available give tetanus antitoxin equine origin in single large dose I.V. I.V. metronidazole large doses for (7-14) days. Wound debridment if possible

d. Maintain adequate airway and give sedation. e. Muscle relaxant drugs with tracheotomy or nasotracheal intubation and mechanical respiration may be life saving . f. Active immunization should be initiated.

Anthrax It is an acute bacterial disease that usually affects skin but may very rarely involve oropharynx, mediastinum, or intestinal tract.

A/Cutaneous Anthrax Presented with itching of an exposed skin followed by papular then vesicular lesion which within (2-6)days proceed into a depressed black Escher with extensive edema. usually it is painless.

Cutaneous Anthrax

B/Inhalation Anthrax Presented initially with mild nonspecific symptoms (flulike) followed by acute symptoms of respiratory distress with x-ray evidence of mediastinal widening, fever and shock within (3-5)days with death shortly thereafter. C/Intestinal Anthrax It is rare and difficult to recognize. Abdominal distress followed by fever, signs of septicemia and death.

*Infectious agent: Bacillus Anthracis (gram positive, encapsulate, spore forming non motile rods).

Occurrence : Human is an incidental host. Sporadic infrequent human infections in most industrialized countries. Endemic in agricultural regions. *It is an occupational hazards primarily of :- 1.Workers with animal hair, bone, and wool processing. 2.Veterinarians and agriculture and wild life workers.

Reservoir: Animals shed bacilli in terminal hemorrhages or blood at death. On exposure to air, vegetative cells sporulate, the spores are resistant to adverse environmental conditions and disinfections. It may remain viable in soil for many years.

Mode of transmission : *Cutaneous infection is by : 1.Contact with tissues of animals dying of the disease .Possibly by fly bite. 2.Contact with hair, and wool or products. 3.Contact with contaminated soil . *Inhalational type through inhalation of spores in risky industrial processes (wool). *Intestinal and or pharyngeal is through ingestion of undercooked contaminated meat.

Incubation period : (1-7) days ( may be up to 60 days). Period of communicability : Person to person transmission is very rare. Articles and soil contaminated with spores may remain infective for decades. Susceptibility and resistance: Uncertain ,there is some evidence of inapparant infection among people in frequent contact with infectious agent. Second attack can occur but rare.

Preventive Measures : 1.Immunize high risk persons with a cell –free vaccine containing protective antigen. 2.Eduacte employees about mode of transmission, care of skin abrasions and personal cleanliness. 3.Control dust and properly ventilate work areas. 4.Thoroughly wash, disinfect or sterilize hair, wool, and bone meal.

5.If anthrax is suspected in animals aseptically collect blood sample for culture then autoclave, incinerate, or chemical disinfection of all instruments or materials used. 6.Prompthly immunize and annually re immunize all animals at risk.

Control Measures : 1.Report to locate health authority .Obligatory case report. 2.Isolation .Standard precautious for the duration of illness. 3.Concurrent disinfection of discharges from lesions and articles. 4.Investigation of contacts and source of infection. 5.Specific treatment. Penicillin is drug of choice for (5-7) days . Alternatives are tetracycline, erythromycin, chloramphenicol, and ciprofloxacin.