Since Meningococcal Meningitis can strike rapidly, and
unexpectedly in healthy individuals, disease surveillance systems have been put
into place to monitor its variance. The
bacterium does not only cause meningitis.
In fact, the cases of people who contract the bacterium, meningitis only
occurs in about 47% (CDC, 2012). This
data has been displayed in the graph below.
To better understand this epidemiological data, I will be showing you
the epidemiology of Meningococcal disease itself, rather than the symptom of
meningitis. Disease surveillance is much
higher for the disease, rather than it’s characteristics. The rate of this disease has been declining
in the United States over the last 20 years.
This is mainly in response to a new vaccination. From 2005-2001, there were an estimated
800-1,200 cases of meningococcal disease that occurred annually in the United
States (Baker, 2013). This means that
there were only about 0.3 cases per 100,000 individuals. Since the vaccine was recommended in 2005,
incidence had declined by 64%, which is reflected in those rates (Baker, 2013).
Who:
Age groups that are at the highest risk are those under the
age of 1, and then a peak begins again around the age of 16-21 (CDC, 2014). Infants have a more difficult time fighting
off infections like this one. This is
the same case for elderly adults. The
adolescent and young adult ages are at risk due to how this disease is
transmitted. Transmission occurs from person
to person through close respiratory secretions or saliva. It is around this age that individuals are
likely to kiss others, share eating utensils, and share drinks. 5-10% of adults are carriers of the bacterium
(Cohn, MacNeil, 2014). This means they
have the bacteria yet do not display any symptoms. This is critical to understand because
transmission can occur without knowing it.
Where:
Almost all cases of Meningococcal disease and the corresponding meningitis are
sporadic, meaning they occur on their own without warning. However sometimes, outbreaks can occur in
small communities, schools, colleges, prisons, military corridors, and other
small populations. An outbreak is
defined as multiple cases in a community of institution over a short duration
of time. These outbreaks occur due to
the simple transmission of disease from living, or working, in tight quarters
(Baker, 2013). This bacterium is not
only limited to the US, but is found worldwide.
Specific areas of Africa have a high incidence of Meningococcal disease.
The area is know as the Belt of Africa and can be seen in the picture
below. In epidemic regions, incidence
rates can be up to 1,000 cases per 100,000 persons (Cohn, MacNeil, 2013). Knowing where disease rates are high is
important information to travelers that can receive vaccines for preventable
disease.
When:
The rise in cases seems to correspond in time with that of
typical flu season, around December or January of each year (CDC, 2014). The immune system
is inherently low at this time, so it is easy for bacteria to swoop in and
cause disease.
Morbidity and Mortality:
Although our rates of Meningococcal disease are at a
historical low, the case fatality ratio remains at 10-15%. This means that out of all the individuals in
the United States that are contracted with the disease, 10-15% of them will
die. Out of those that survive, 11-19%
have long term disabilities. These
disabilities often include neurological disability, limb or finger loss, and
hearing loss (Baker, 2013).
BIBLIOGRAPHY
Baker, C., Briere, E., Clark, T., Cohn, A., MacNiel, J.,
Meissner, H., Messonnier, N., Ortega,
I. (2013, Mar 22). Prevention and
Control of Meningococcal Disease: Recommendations
of the Advisory Committee on Immunization Practices. Retrieved
from http://www.cdc.gov/mmwr/preview/mmwrhtml/rr6202a1.htm
Cohn, A., MacNeil, J., (2014, April 1) Meningococcal
Disease: Manual for the Surveillance of
Vaccine Preventable Diseases. Retrieved from http://www.cdc.gov/vaccines/pubs/surv-manual/chpt08-mening.html
Cohn, A., MacNeil, J., (2013, August 1) Infectious Disease
Related to Travel. Retrieved from http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-3-infectious-diseases-related-to-travel/meningococcal-disease
Centers for Disease Control and Prevention. (2012, May 7).
Meningococcal Disease. Retrieved
from http://www.cdc.gov/vaccines/pubs/pinkbook/mening.html
Centers for Disease Control and Prevention. (2014, April 1)
Surveillance. Retrieved from http://www.cdc.gov/meningococcal/surveillance/index.html
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