Content Information
Disease Information
Tetanus is caused by a potent toxin produced by Clostridium tetani, a spore-forming, anaerobic, gram-positive bacillus.
Overview
Also known as: Lockjaw disease
Responsibilities
- Hospital: Report by IDSS, facsimile, mail or phone
- Lab: Report by facsimile, mail or phone
- Physician: Report by IDSS, facsimile, mail or phone
- Local Public Health Agency (LPHA): Report by IDSS, mail, facsimile, or phone. Follow-up required
Iowa Department of Public Health
Disease Reporting Hotline: (800) 362-2736
Secure Fax: (515) 281-5698
A. Agent
Tetanus is caused by a potent toxin produced by Clostridium tetani, a spore-forming, anaerobic, gram-positive bacillus.
B. Clinical Description
Generalized tetanus is an acute, often fatal neurologic disease characterized by painful skeletal muscular contractions. The toxin blocks nerve signals telling muscles not to contract in response to voluntary contractions of opposing muscles. Onset is gradual, occurring over 1 - 7 days. The muscle stiffness usually first involves the jaw (lockjaw) and neck and progresses to severe generalized muscle spasms, which frequently are aggravated by any external stimulus, such as a loud noise. Severe spasms persist for one week or more and subside over a period of weeks in those who recover. C. tetani usually enters the body through a penetrating or puncture wound. In the presence of anaerobic (low oxygen) conditions, the spores germinate. Toxins are produced, and disseminated via blood and lymphatics. Toxins act at several sites within the central nervous system, including peripheral motor end plates, spinal cord, brain, and sympathetic nervous system. The typical clinical manifestations of tetanus are caused when tetanus toxin interferes with release of neurotransmitters, which block inhibitor impulses, resulting in sustained spasms. This leads to unopposed muscle contraction and spasm. Seizures may occur, and the autonomic nervous system may also be affected.
Neonatal tetanus, which arises from infection of the umbilical stump, is a form of generalized tetanus. However, inability to nurse is the most common presenting sign. Localized tetanus is manifested by local muscle spasms in areas contiguous to a wound, although history of an injury or an apparent portal of entry may be lacking. Cephalic tetanus is a rare form of the disease and involves the cranial nerves, especially the facial area. It is associated with infected wounds of the head and neck, including ear infections. Both localized and cephalic tetanus may precede generalized tetanus.
Complications of the disease include laryngospasm (spasm of the vocal cords) and/or spasm of the muscles of respiration, leading to interference with breathing; fractures of the spine or long bones, resulting from sustained contractions and convulsions; and hyperactivity of the autonomic nervous system, which may lead to hypertension and/or an abnormal heart rhythm. Other complications may include increased susceptibility to nosocomial infections, pulmonary embolism (particularly in drug addicts and elderly patients), and aspiration pneumonia. The case-fatality rate ranges from 10% - 90%; it is highest in infants and the elderly and varies inversely with the length of the incubation period and the availability of experienced intensive care unit personnel and resources.
Tetanus disease does not confer immunity. Patients who survive the disease should be given a complete series of vaccine.
Laboratory confirmation is of little help. The organism is rarely recovered from the site of infection, and usually there is no detectable serological response.
C. Reservoirs
Clostridium tetani is a normal inhabitant of soil and animal and human intestines. It is ubiquitous in the environment, especially where contamination by excreta is frequent.
D. Modes of Transmission
There is no person-to-person transmission of tetanus. Wounds, recognized or unrecognized, are the sites at which the organism enters the body, multiplies, and produces toxin. Cases of tetanus have followed injuries considered too trivial for medical consultation.
E. Incubation Period
The incubation period ranges from 2 days to months, with most cases occurring within 14 days. In neonates the incubation period is usually 5 - 14 days. In general, shorter incubation periods are associated with more heavily contaminated wounds, more severe disease, and a worse prognosis.
F. Period of Communicability or Infectious Period
There is no infectious period because tetanus in not transmitted person-to-person.
G. Epidemiology
Tetanus occurs worldwide and is more frequent in warmer climates and months, partly because of the frequency of contaminated wounds. Despite the availability of tetanus toxoid (TT), tetanus continues to have a substantial health impact in the world. In 2011, neonatal tetanus alone accounted for an estimated 61,000 deaths worldwide. Tetanus is sporadic and relatively uncommon in the United States and most industrial countries, mostly because of widespread use of tetanus toxoid as part of routine immunizations and improved wound management. During 2001 through 2008, the last years for which data have been compiled, a total of 233 tetanus cases was reported, an average of 29 cases per year. Among the 197 cases with known outcomes the case-fatality rate was 13%. Almost all reported cases have occurred in people who had never been vaccinated or who completed a primary series but had not had a booster dose in the preceding 10 years. In the U.S., 49% tetanus cases occurred in persons 50 years of age or older. Neonatal tetanus is rare in the U.S., with only two cases reported since 1989. Neither of the infants’ mothers had ever received tetanus toxoid.
Heroin users, particularly those who inject themselves subcutaneously with quinine-cut heroin, appear to be at high risk for tetanus. Quinine is used to dilute heroin and may actually favor growth of C. tetani.
Today, tetanus in the U.S. affects primarily older adults. The last reported case of neonatal tetanus in the U.S. occurred in 1998 in Montana in a newborn whose umbilical stump had been treated with nonsterile clay. The last case in Iowa was in 2013. From 1994 through 2008, Iowa had 6 cases of tetanus reported, 2 of which were known to be fatal. Both fatalities were elderly women who had never received Td vaccine. Elderly women may be at greater risk of illness and death because they may never have received vaccine. Males often were vaccinated in the military, thus may at least have some protection.
H. Bioterrorism Potential
None.
I. Additional Information
The Council of State and Territorial Epidemiologists (CSTE) surveillance case definitions for Tetanus can be found at: www.cdc.gov/osels/ph_surveillance/nndss/phs/infdis.htm#top
CSTE case definitions should not affect the investigation or reporting of a case that fulfills the criteria in this chapter. (CSTE case definitions are used by the state health department and the CDC to maintain uniform standards for national reporting.)
Fact Sheets and Forms
References
American Academy of Pediatrics. Red Book 2009: Report of the Committee on Infectious Diseases, 28th Edition. Illinois, Academy of Pediatrics, 2009.
CDC. Epidemiology & Prevention of Vaccine-Preventable Diseases: The Pink Book, 11th Edition. CDC, January 2009.
Manual for the Surveillance of Vaccine-Preventable Diseases. 4th Edition CDC, 2008-2009. www.cdc.gov/vaccines/pubs/surv-manual/
CDC. Surveillance Summaries. Tetanus Surveillance-United States, 1995-1997. MMWR. July 3, 1998; 47:SS-2.
Heymann, David L., ed. Control of Communicable Diseases Manual, 20th Edition. Washington, DC, American Public Health Association, 2015.