Diphtheria Outbreak -- Russian Federation, 1990-1993

Morbidity and Mortality Weekly Report (MMWR), vol. 42, no. 43, November 5, 1993.

Despite high levels of vaccination coverage against diphtheria, an ongoing outbreak of diphtheria has affected parts of the Russian Federation since 1990 (1); as of August 31, 1993, 12,865 cases had been reported. This report summarizes epidemiologic information about this outbreak for January 1990-August 1993, and is based on reports from public health officials in the Russian Federation.

 

In the Russian Federation, diphtheria surveillance data are reported by physicians to the local reporting center of the Sanitary Epidemiologic Service (SES). Tabulated cases are reported to regional SESs, then forwarded to the Russian Republican Information and Analytic Center for compilation of national morbidity statistics, which are published monthly in The Health of the Population and the Environment. Diphtheria cases are investigated by local epidemiologists; case investigation forms are forwarded to the Gabrichevsky Research Institute of Epidemiology and Microbiology in Moscow for further analysis.

Reported cases of diphtheria in the Russian Federation increased from 1211 (0.8 cases per 100,000 population) in 1990 to 3897 (2.6) in 1992 (Figure 1). In 1992, reported cases increased twofold over those reported in 1991; in comparison, during January-August 1993, reported cases (5888) increased threefold over those reported during the same period in 1992.

In 1992, 2798 (72%) of the 3897 reported cases were among persons aged greater than 14 years; the case-fatality ratio was less than 5%. Approximately 98% of reported cases were bacteriologically confirmed.

An estimated 80% of children in the Russian Federation had started their primary diphtheria-tetanus-pertussis (DTP) vaccination series* before their first birthday. However, a substantial proportion of these children received fewer than three doses by that age: during 1991, 69% of children in Moscow received one or more doses of diphtheria toxoid-containing vaccine by their first birthday; 43%, two or more doses; and 23%, three doses. However, an estimated 90% of children were fully vaccinated with four or more doses of diphtheria toxoid by the time they entered school.

In 1983, the State Committee on Sanitary Epidemiologic Surveillance (SCSES) initiated a policy requiring vaccination of adults with one dose of diphtheria toxoid; however, coverage with booster doses remains low. Current efforts to control the outbreak have focused on increasing vaccination coverage among all age groups; preliminary assessment suggests that vaccine efficacy is high (Moscow SES; SCSES; CDC, unpublished data, 1993).

Reported by: IN Lyetkina, NN Filatov, Moscow Sanitary Epidemiologic Service; SS Markina, Gabrichevsky Research Institute of Epidemiology and Microbiology; LG Podunova, Russian Republican Information and Analytic Center; EA Kotova, VI Chiburaev, AA Monisov, State Committee on Sanitary Epidemiologic Surveillance. National Immunization Program, CDC.

Editorial Note: The outbreak of diphtheria in the Russian Federation is the largest diphtheria outbreak in the developed world since the 1960s; similar levels have not been reported in the United States since the early 1950s. In addition, an outbreak of diphtheria has been reported from Ukraine, and increased diphtheria activity has been reported from many of the other New Independent States that had been members of the Soviet Union (2).

The outbreak described in this report illustrates that, despite a high vaccination coverage rate among school-aged children, diphtheria can cause epidemic disease in developed countries. Strategies to control outbreaks and prevent further transmission of diphtheria include maintenance of high levels (greater than 80%) of diphtheria vaccination coverage, ongoing surveillance, and intensive follow-up case investigation.

The findings in this and previous reports underscore three important points about the epidemiology of diphtheria. First, seroprevalence studies in the United States, the Russian Federation, and other developed countries indicate that large numbers of adults remain susceptible to diphtheria (3- 8). Although factors related to the occurrence of the outbreaks in the Russian Federation and Ukraine are under investigation, high levels of susceptibility to diphtheria--particularly among adults--have probably played an important role in sustaining transmission of infection. Second, because diphtheria remains endemic in many developing countries, these countries are a potential source for introduction of infection into developed countries. Third, the outbreak in the Russian Federation demonstrates that widespread transmission can occur in developed countries, particularly in urban areas. However, the importance of other factors (e.g., migration and crowding) also requires clarification.

The risk for exposure to diphtheria cannot be readily quantified for persons who may travel to areas with endemic activity or outbreaks. Diphtheria has been reported in a visitor to the Russian Federation (9). To minimize the risk for diphtheria, the Advisory Committee on Immunization Practices recommends the following measures for all U.S. residents, especially those traveling to countries with endemic diphtheria: 1) completion of a primary series with diphtheria toxoid-containing vaccine (persons aged greater than or equal to 7 years: three doses of adult formulation tetanus-diphtheria toxoid; children aged less than 7 years: four doses of DTP vaccine [for children aged less than 7 years with a contraindication to pertussis vaccine: infant formulation diphtheria-tetanus toxoid]) and 2) receipt of the most recent dose of this vaccine (either primary series or booster dose) within the previous 10 years (10).

Signs and symptoms

Signs and symptoms of diphtheria may include:

§ A sore throat and hoarseness

§ Painful swallowing

§ Swollen glands (enlarged lymph nodes) in your neck

§ A thick, gray membrane covering your throat and tonsils

§ Difficulty breathing or rapid breathing

§ Nasal discharge

§ Fever and chills

§ Malaise

Signs and symptoms usually begin two to five days after a person becomes infected, but they may take as many as 10 days to appear. You may mistake diphtheria in its initial stages for a bad viral sore throat. Other early symptoms include a mild fever and swollen glands in the neck — signs and symptoms of other, much more common types of infection such as strep throat or mononucleosis.

The bacterium that causes diphtheria attacks mucous membranes that line the nose and throat and cover the tonsils. The throat becomes inflamed. The inflammation may spread to the voice box (larynx) and may make your throat swell, narrowing your airway.

A hallmark sign
The bacteria may produce a toxin that can lead to a thick, gray covering in your nose, throat or airway — a marker of diphtheria that separates it from other respiratory illnesses. This covering is usually fuzzy gray or black and causes breathing difficulties and painful swallowing.

In more advanced stages, a person with diphtheria may have severe difficulty breathing and may show signs of respiratory distress such as rapid breathing, a rapid heartbeat and cold, clammy skin.

Some people become infected with diphtheria-causing bacteria, but they develop only a mild case of the illness and show no signs or symptoms of the disease. They're said to be carriers of the disease, because they may be contagious without showing signs or symptoms of illness.

Skin (cutaneous) diphtheria
Diphtheria occurs in two types. One type involves the mucous membranes of your nose and throat, and the other involves the skin. A wound infected with bacteria is typically red, painful and swollen. A wound infected with diphtheria-causing bacteria also may have patches of a sticky, gray material.

Although it's more common in tropical climates, cutaneous diphtheria also occurs in the United States, particularly among people with poor hygiene who live in crowded conditions.

In rare instances, diphtheria affects the eye

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Diphtheria causes a characteristic swollen neck, sometimes referred to as “bull neck”.

The respiratory form has an incubation period of 2-5 days. The onset of disease is usually gradual. Symptoms include fatigue, fever, a mild sore throat and problems swallowing. Children infected have symptoms that include nausea, vomiting, chills, and a high fever, although some do not show symptoms until the infection has progressed further. In 10% of cases, patients experience neck swelling. These cases are associated with a higher risk of death.

In addition to symptoms at the site of infection (sore throat), the patient may experience more generalized symptoms, such as listlessness, pallor, and fast heart rate. These symptoms are caused by the toxin released by the bacterium. Low blood pressure may develop in these patients. Longer-term effects of the diphtheria toxin include cardiomyopathy and peripheral neuropathy (sensory type)[2].

 

 

A diphtheria skin lesion on the leg.

 

The cutaneous form of diphtheria is often a secondary infection of a preexisting skin disease. Signs of cutaneous diphtheria infection develop an average of 7 days after the appearance of the primary skin disease.

 

Diagnosis

The current definition of diphtheria used by the Centers for Disease Control and Prevention (CDC) is based on both laboratory and clinical criteria.

Laboratory criteria

  • Isolation of Corynebacterium diphtheriae from a clinical specimen, or
  • Histopathologic diagnosis of diphtheria.

Clinical criteria

  • Upper respiratory tract illness with sore throat
  • Low-grade fever, and
  • An adherent membrane of the tonsil(s), pharynx, and/or nose.

Case classification

  • Probable: a clinically compatible case that is not laboratory confirmed and is not epidemiologically linked to a laboratory-confirmed case
  • Confirmed: a clinically compatible case that is either laboratory confirmed or epidemiologically linked to a laboratory-confirmed case

Empirical treatment should generally be started in a patient in whom suspicion of diphtheria is high.

 

Risk f actors

Children younger than 5 years old and adults older than 60 are particularly at risk of contracting diphtheria, as are:

§ People living in crowded or unsanitary conditions

§ Undernourished people

§ Children and adults who don't have up-to-date immunizations

§ People who have a compromised immune system

Diphtheria is rare in the United States and Europe, where health officials have been immunizing children against it for decades. In the United States, fewer than five cases have occurred each year since 1980, according to the Centers for Disease Control and Prevention.

However, diphtheria is still common in developing countries where immunization rates are low. For example, large outbreaks of diphtheria occurred in the 1990s throughout Russia and the independent countries of the former Soviet Union, resulting in some 5,000 deaths. Control measures have since been implemented, but a risk of diphtheria remains in those areas.

Most cases of diphtheria occur in unvaccinated or inadequately vaccinated people. Diphtheria poses a threat to U.S. citizens who may not be fully immunized and who travel to other countries or have contact with immigrants or international travelers coming to the United States.

 

 

HERE THERE ARE FEW QUESTION AND ANSWERS ON DIPHTHERIA

Diphtheria

Describe the clinical picture of Diphtheria

The answer

  • Is an acute contagious illness
  • Diphtheria is the result of local and systemic effects of diphtheria toxin.
  • It is characterized by membrane formation in throat.
  • Diphtheria is primarily an illness of children

 

Describe Corynebacterium diphtheriae, its morphologic, cultural characteristics and their normal habitat and life cycle..

The answer

  • Source
    • Humans are the only reservoir of infection
    • Infection may produce disease or a carrier state
  • Morphology
    • Aerobic, club shaped, gram-positive, nonmotile, unencapsulated, pleomorphic bacillus with terminal swellings
    • When stained it is often found in clusters that form sharp angles with each other and resemble Chinese letters.
  • Culture
    • Missed on routine cultures

 

Who are the susceptible hosts forCorynebacterium diphtheriae

The answer

  • Children not vaccinated for C. diphtheria.
  • Poorly immunized adults
  • Immunocompromised

 

How does Corynebacterium diphtheriae get exposed to humans?

The answer

  • Respiratory droplets
  • Direct contactwith cutaneous infection
  • Fomites
    • Nasopharyngeal secretions
    • The organisms can survive in dusts and clothing for up to 6 months.

 

How does Corynebacterium diphtheriae invade and spread in humans? Describe the pathogenic mechanisms. How do these organisms able to overcome human defenses?