Post on 19-Oct-2020
Running head: PERTUSSIS 1..
Understanding the Epidemiology of Pertussis
Jessie McCarty
Concordia University
PERTUSSIS 2.
Define the Problem
Pertussis, also known to the general public as whopping cough, is an infection caused by
bacteria. This bacterial infection is caused by Bordetella pertussis and leads to a harsh cough
with multiple possible complications. Bordetella pertussis can be highly contagious, especially
in children, and in some cases, infection from pertussis can be fatal (Hockenberry, 2003).
Pertussis can be prevented, and the number of cases drastically reduced, by immunizing
communities. Therefore, pertussis is a disease of great significance to public health departments
throughout the United States and globally.
Due to the rising number of cases of pertussis throughout the United States, public health
departments nationally are starting to recognize the seriousness of this epidemic. Since the
1980’s, documented pertussis cases have increased (CDC, 2012b). A high peak occurred in
2004, with 25, 827 cases reported and another peak started in 2010 with 27,550 cases (CDC,
2012b). The peak of 2010 started to gradually decline in 2011 nationally. It is also important to
note many cases of pertussis are not reported and therefore, the amount of national cases is
higher than what the actual data shows. March of Dimes (2012) stated “It is estimated that up to
3.3 million cases of pertussis occur each year in adults and adolescents”. This number suggests
the majority of cases are not even reported and the epidemic is much larger than what the data
shows. The chart below shows the gradual increase of pertussis rates since 1980 and the peak in
2004 (CDC, 2012b).
PERTUSSIS 3.
(CDC, 2012b)
Pertussis can be a serious disease which can lead to serious complications and even
death. Bordetella pertussis is a preventable disease within a community when the public is
properly immunized. However, the number of people infected with pertussis on a yearly basis is
continuing to rise (Carmon & Spratling, 2010). According to March of Dimes (2012) “It's the
only vaccine-preventable disease that has been on the rise”. With the increased rates of pertussis
since the 1980’s, despite immunization availability, it is clear there are other factors contributing
to the increase of pertussis infections. Studying the epidemiology behind pertussis can lead to a
better understanding behind the growth of pertussis cases. In order to control and prevent
pertussis epidemics, public health departments must have an in-depth understanding of pertussis
and the multiple factors contributing to the epidemiology of this disease.
Describe the Agent
Bordetella pertussis is a gram-negative bacteria (CDC, 2012). This gram negative
bacteria produces many biologically and molecular responses. The presence of Bordetella
pertussis “produces multiple antigenic and biologically active products including pertussis toxin,
filamentous hemagglutinin (FHA), agglutinogens, adenylate cyclase, pertactin, and tracheal
cytotoxin” (CDC, 2012a). These responses to the gram negative Bordetella pertussis presence
then cause the signs and symptoms that present in the human infected with Bordetella pertussis.
PERTUSSIS 4.
The typical reservoir for Bordetella pertussis is a young child typically under the age of
five (McCance & Huether, 2006). Bordetella pertussis is a bacterium that typically affects young
children, specifically those who have not been immunized to pertussis (Hockenberry, 2003).
However, it is important to once again note Bordetella pertussis can affect adolescents and
adults.
After affecting one person, the pathogen finds its place of exit to go get transmitted
elsewhere. Pertussis is often transmitted via droplet transmission or contact transmission
(Hockenberry, 2003). Often, the pathogen is transmitted via a cough. The Bordetella pertussis
pathogen exits the infected person’s mouth by a cough and then is spread directly through the air
into another person’s airway. However, the pathogen can exit via a cough onto an object which
then transmits the bacteria via contact.
Once Bordetella pertussis is transmitted, it is able to enter the body of a new host by
droplet or contact transmission. The port of entry is typically the mouth. The droplets of the
pathogen can be inhaled by a new host via a cough. Also, not washing hands after touching
infected objects can also provide a way for contact transmission if people touch their faces with
contaminated hands. A susceptible host is often someone around the infected person. However,
those most susceptible are young children, those who are not vaccinated, and those with direct
exposure to others with Bordetella pertussis, such as family members.
Describe the Condition
The “incubation period for pertussis is most commonly seven to ten days, with a range of
four to twenty-one days” (Carmon & Spratling, 2010, p.239). The Bordetella pertussis
pathogen attaches “to the cilia of the respiratory epithelial cells, produce toxins that paralyze the
cilia, and cause inflammation of the respiratory tract, which interferes with the clearing of
PERTUSSIS 5.
pulmonary secretions” (CDC, 2012). This process of infection causes the signs and symptoms
related to pertussis. These signs and symptoms include “severe coughing, whooping, and post-
tussive vomiting which can last for many weeks” (Carmon & Spratling, 2010, p.239).
Pertussis infections can typically be separated into three stages: catarrhal, paroxysmal,
and convalescent stages (Carmon & Spratling, 2010). The first stage, catarrhal stage, can mimic
the common cold with symptoms such as sneezing, low grade fever, rhinorrhea, and a minor
cough. However, next in the paroxysmal stage, coughing worsens and a whooping noise is often
heard after a cough (Rittle, 2010). Also, it is important to note other symptoms, such as fever,
cyanosis, and post-tussive emesis, may also be present during this stage, especially with young
infants (Carmon & Spratling, 2010). Carmon & Spratling (2010) noted this stage “can last up to
ten weeks, with a typical duration of one to six weeks” (p.239). After the completion of the
second stage, the third and final stage, convalescent stage then starts. This stage is typically two
to three weeks but may last for months. Often, this stage consists of less severe symptoms and
the body recuperating.
Morbidity and Mortality Data
The World Health Organization (WHO) reported 139, 382 cases of pertussis globally for
2011 with 195,000 deaths worldwide (WHO, 2012). As aforementioned, there was a
documented peak in cases of pertussis in 2010 with the CDC reporting 27,550 cases and a
gradual decline in 2011 showing 18,719 (CDC, 2012a). The CDC (2012a) stated “Provisional
counts from our surveillance system indicate that more than 41,000 cases of pertussis were
reported to CDC during 2012”. If these numbers prove true, this would mean the United States
saw another peak of pertussis, higher than the peaks in 2004 and 20012. The chart below shows
rates of pertussis cases annually from 2000-2011 (CDC, 2012a).
PERTUSSIS 6.
Year Reported Cases*2000 7,8672001 7,5802002 9,7712003 11,6472004 25,8272005 25,6162006 15,6322007 10,4542008 13,2782009 16,8582010 27,5502011* 18,719
*Total reported cases include those with unknown age.(CDC, 2012a)
Data in the United States shows, after the peak of cases in 2004, 111 deaths related to
pertussis were documented between 2004 and 2008 (CDC, 2012b). In 2010, there were 27
deaths from pertussis (CDC, 2012a). CDC (2012a) stated “18 pertussis-related deaths during
2012 have been reported to CDC as of January 5, 2013. The majority of deaths continue to occur
among infants younger than 3 months of age”. Looking at data on morbidity and mortality for
pertussis, it is clear to see infants and young children are not only most likely to get this disease,
but also most likely to die from pertussis. March of Dimes (2012) even stated “92% of deaths
from pertussis occur in babies under 4 months of age”. In 2010, within the United States, there
were more than 18 documented deaths of infants from pertussis (March of Dimes, 2012). The
below chart further emphasizes the dangers of pertussis for infants.
PERTUSSIS 7.
Age at onset <3 mos >3 mos Total2004 23 4 272005 32 7 392006 12 5 162007 9 2 112008 16 2 18Total 92
(83%)20(17%)
111
Pertussis Deaths in the United States, 2004-2008(CDC, 2012b)
Host Characteristics
Age
Pertussis is a preventable disease with a known vaccine. However, pertussis still
continues to affect multiple children, adolescents, and adults every year. Cases of pertussis are
usually found in children, typically at the age of four and under (Hockenberry, 2003). CDC
(2012b) stated “The incidence rate of pertussis among infants exceeds that of all other age
groups. The second highest rates of disease are observed among children 7 through 10 years
old”. Many cases of pertussis reported in children and infants are reported in those who have not
received the immunization for Bordetella pertussis or have decreased immune function. Carmon
& Spratling (2010) even stated “the number of reported cases of pertussis has steadily increased,
particularly among the infant and adolescent age groups” (p.239). CDC (2012b) also
emphasized the importance of immunizing infants and children by stating “During 2001–2003,
the highest average annual pertussis incidence was among infants younger than 1 year of age
(55.2 cases per 100,000 population), and particularly among children younger than 6 months of
age (98.2 per 100,000 population). In 2002, 24% of all reported cases were in this age group”.
These statistics further stress the importance of immunizing infants as soon as possible.
PERTUSSIS 8.
Although cases of pertussis are usually talked about in reference to young children,
pertussis can affect adolescents and adults also. The increased infection rates in adolescents and
adults are believed to be correlated to eventually no longer having immunity from vaccinations
given in childhood (SuMi, HyunSoo, OkKyung, Moon-Hyun,& WhaSook, 2010). Also,
adolescents and adults with pertussis typically have more mild symptoms and the bacterial
infection is not as severe (Crose, Cruz, & Tornabene, 2012). CDC (2012b) stated “adolescents
(11–18 years of age) and adults (19 years and older) have accounted for an increasing proportion
of cases. During 2001–2003, the annual incidence of pertussis among persons aged 10–19 years
increased from 5.5 per 100,000 in 2001, to 6.7 in 2002, and 10.9 in 2003. In 2004 and 2005,
approximately 60% of reported cases were among persons 11 years of age and older”. Hence,
there is an obvious growing trend of adolescents and adults getting pertussis. The graph below
further shows this trend (CDC, 2012b).
(CDC, 2012b)
Sex
Unlike many diseases, research has not found a clear gender discrepancy with pertussis.
There are small studies which suggest females have higher rates of pertussis but many of these
studies have been discredited by larger studies. The majority of peer-reviewed research does not
show a definitive link between gender and pertussis. Fishman et al. (2011) stated “There was no
PERTUSSIS 9.
clinically significant change in proportions tested…gender” (p. 4). Also, Cagney, Macintyre,
Mcintyre, Puech, & Giammanco (2006) stated “Despite the female predominance of pertussis
notifications in the period covered by the study, we found no significant gender-specific
differences” (p. 1215). Based on the lack of correlation between sex and pertussis through
research, public health workers must assume both sexes are at equal risk for pertussis.
Race and Ethnicity
Pertussis can affect anyone of any race. However, in the United States, Caucasians are
most at risk for getting pertussis. CDC (2005) stated “Data on race was available for 24,024
(83%) persons with pertussis. Of these, 21,597 (90%) were white, 1,621 (7%) were black, 288
(1%) were American Indian/Alaska Native, 337 (1%) were Asian/Pacific Islander, and 181 (1%)
were identified as "other race”. This data proves a correlation between Caucasians and pertussis
infections. CDC (2005) further emphasized this racial correlation by stating “Among all age
groups, the incidence of reported cases was twice as high among whites as among blacks”.
A correlation between Hispanic ethnicity and pertussis should also be noted. CDC
(2005) explained “Data on Hispanic ethnicity was available for 23,669 (82%) persons with
pertussis. Of these, 3,871 (16%) were Hispanic. Among infants aged <6 months, 1,701 (29%) of
5,872 with pertussis were Hispanic; by comparison, an estimated 18% of infants born each year
in the United States are Hispanic”. This data suggests a strong link between pertussis and
Hispanic ethnicity, especially in the infant age group.
Environmental Attributes
Geographical Areas
Anyone living in the United States is at risk for pertussis, especially if not immunized.
However, there are certain areas throughout the United States which have seen more cases of
PERTUSSIS 10.
pertussis than others. For example, in 2012, the state with the most reported cases of pertussis
was Wisconsin followed by Minnesota, Vermont, and Washington (CDC, 2012a).
Many states have declared pertussis epidemics in 2012, including Wisconsin. According
to Wisconsin Department of Health Services (WDHS, 2013) “As of January 14, 2013, 6,189
cases (4,502 confirmed and 1,687 probable) of pertussis with illness onsets during 2012 have
been reported among Wisconsin residents”. The WDHS (2013) goes on to state “The recent
reported pertussis activity is the most observed since the large pertussis outbreak that occurred
during 2004-05. More than 5,600 reported cases occurred during 2004”. As aforementioned,
much of the data nationally from 2012 is showing higher numbers of pertussis cases than in the
last peak of 2004.
Although certain states may report higher cases of pertussis, it is important to keep in
mind certain states also have more organized systems of reporting infectious diseases than
others. Also, many cases of pertussis are not reported, or even diagnosed, especially in rural
areas. The below graphs and pictures help summarize which states have the highest pertussis
incidences.
States with incidence of pertussis the same or higher than the national incidence (as of November 23, 2012), which is 11.6/100,000 personsWisconsin 93.4 New Mexico 31.0 Arizona 13.5Minnesota 78.1* Alaska 28.6 Illinois 13.5Vermont 66.1 North Dakota 25.6 Idaho 13.1Washington 64.3 Oregon 22.1 Pennsylvania 12.9Iowa 47.5 Kansas 21.9 Missouri 12.3Maine 45.6 New Hampshire 15.7 - -Montana 44.3 Colorado 15.2 - -Utah 40.9 New York 14.5 - -
(CDC, 2012a)
PERTUSSIS 11.
(March of Dimes, 2012)
Social and Economic Factors
There are social and economic factors to take into account when studying pertussis.
Those exposed to smoke in their environment may be more susceptible to pertussis (Saadi et al.,
1996). This susceptibility is especially true for infants. Research has shown infants’ immune
responses to pertussis are slower when they are exposed to environments with smoke present
(Saadi et al., 1996).
Close living quarters is another social factor linked to a higher number of cases of
pertussis. A living situation where multiple people are present in a small area can enhance the
spread of pertussis. As aforementioned, pertussis can spread from close contact or by “indirect
contact with freshly contaminated articles” (Hockenberry, 2003, p. 656). Therefore, if pertussis
infects someone living in an environment with multiple people present, the disease can spread
easily to these other people. Those with a low income are more likely to live in this type of
living situation and public health departments must recognize this correlation.
PERTUSSIS 12.
Not only do those with a low income tend to live in housing situations which may make
them more susceptible for pertussis, but often those with low income often cannot afford
immunizations. Providing public programs for discounted or free vaccines is one way to make
sure children are vaccinated and adolescents and adults receive booster vaccines. Carmon &
Spratling (2010) explained “The pertussis vaccine is the most effective means for disease
prevention. The primary risk factor for pertussis is being unprotected or inadequately protected
from immunizations” (p. 241). Therefore, providing affordable vaccines is a reliable way to
encourage vaccinations, slow down the spread of the disease, and decrease the correlation
between low income and high risk for pertussis.
Occupation
There is no definitive correlation between occupation and pertussis cases. However,
those working in healthcare with exposure to pertussis are at a greater risk for pertussis due to
pertussis being highly contagious. Health care works can decrease their risk by quickly
recognizing the symptoms of pertussis and properly placing patients in isolation. Use of masks
and gowns is recommended in healthcare settings when interacting with patients with pertussis
symptoms.
Also, those working with small children, such as daycare workers and school teachers,
are at higher risk for pertussis infection since children are more likely to be infected with
pertussis. If children are infected with pertussis, they should not be attending school or day care
until cleared by a doctor to limit the spread of the infection.
Education
Although there is no clear link between a certain education level and pertussis infections,
general education about the disease will help decrease the spread of pertussis. Those in public
PERTUSSIS 13.
health must first make certain the public knows pertussis is a serious disease which can have
severe complications. Often, the public does not understand what pertussis is and who is
vulnerable to pertussis. Also, people assume they have had a vaccination once as a child and are
protected. Therefore, people do not feel vulnerable to the disease. Rittle (2010) stated “Many
adults think that pertussis is a thing of the past” (p.283). By educating the public about the
seriousness of pertussis and the continuation of the spread of pertussis, the public will understand
they are vulnerable to the disease and there is a threat. Education must also be provided to the
public on the effectiveness of the pertussis vaccine. By showing the vaccine works, and by
eliminating obstacles to getting the vaccine, the public will be more likely to get immunized.
Temporal Variation
Secular
According to the CDC (2012b) “Before the availability of a vaccine, pertussis was a
common cause of morbidity and mortality among children. During the 6-year period from 1940
through 1945, more than 1 million cases of pertussis were reported”. Vaccine introduction in
1940s helped to decrease the rates of pertussis and there were fewer than 5,000 annual cases in
1970 (CDC, 2012b). However, as mentioned earlier, in the 1980’s pertussis cases began to
increase and continue to grow. The below chart shows the secular trend in Pertussis from 1940-
2009 (CDC, 2012b).
PERTUSSIS 14.
(CDC, 2012b) Cyclic
Cherry (2005) stated “In the prevaccine era pertussis epidemics followed a cyclic pattern,
with peaks every 2 to 5 years” (p.1422). . Unlike some diseases which occur in cycles and can
be predicted, pertussis has just been on a steady incline, with occasional peaks, since the 1980s
(CDC, 2012a). However, as noted by peaks in 2004, 2010, and the new numbers showing a
peak in 2012, one could infer the disease is following a cyclic pattern again. Cherry (2005)
explained “With the marked reduction of pertussis by vaccination, the same cyclic pattern still
occurs” (p.1422). Although not all researches agree pertussis is becoming cyclic, with trending
of peaks in the last 8 years, it is reasonable to suggest.
Seasonal
Pertussis can infect people at any time. However, the highest rates of pertussis in the
United States have been linked to the spring and summer months (Hockenberry, 2003). On the
contrary, CDC (2012b) reported “Pertussis has no distinct seasonal pattern, but it may increase in
the summer and fall”. This link between these seasons and pertussis has been noted throughout
the United States, although there is not a definitive cause as to why there is a correlation.
Epidemic
As aforementioned, pertussis cases have increased since 1980’s and there have been
peaks in 2004, 2010, and 2012. All of these peaks show an increase in cases of pertussis and
PERTUSSIS 15.
epidemics in the United States. Pertussis is a highly contagious disease and thus, even after
epidemics, the disease has a gradual decline in the next years and not a rapid decrease in the
disease. In 2012, many states declared epidemics of pertussis including Washington, Vermont,
and Wisconsin (CDC, 2012a). The below map shows the variation of the number of documented
cases of pertussis throughout the United States (CDC, 2012a). Many of the dark purple states
shown have had recent epidemics.
(CDC, 2012a)
Hypotheses Explaining Observed Distribution
As pertussis rates have increased since the 1980’s, people have speculated why there is
an increasing trend despite the availability of a vaccine. The introduction of a vaccine initially
proved to drastically slow down the spread of pertussis. CDC (2012b) stated “Following
introduction of whole-cell pertussis vaccine in the 1940s, pertussis incidence gradually declined,
reaching 15,000 reported cases in 1960 (approximately 8 per 100,000 population). By 1970,
annual incidence was fewer than 5,000 cases per year, and during 1980–1990, an average of
2,900 cases per year were reported”. However, in the 1980’s the rates of pertussis increased and
have never decreased to the numbers seen in the 1970’s. The below graph shows the drastic
decrease of pertussis rates after introduction of the vaccine.
PERTUSSIS 16.
(CDC, 2012b)
Some people believe pertussis rates are inaccurate due to the increased reporting, mainly
stemming from mandatory reporting in many states. Reporting of pertussis has not always been
mandatory and testing to confirm pertussis was not always available. Therefore, some argue
pertussis rates have not actually increased, but instead, the diagnosing and reporting availability
have simply increased.
The CDC also recognizes the correlation between increased reporting and rates. The
CDC (2012a) stated “Increased recognition and diagnosis of pertussis in older age groups
probably contributed to this increase of reported cases among adolescents and adults”.
However, diagnosis in younger children and infants has been prevalent for years and still shows
a rising rate. Therefore, there must be more behind the increasing rates than just the easier
ability to report data.
There are people who believe the pertussis vaccine is not helpful in protecting the public
from pertussis. However, scientific research has shown the vaccine does work in preventing
pertussis if given correctly and boosters are given. Cherry (2005) explained “data presently
exists that suggest that vaccine-induced immunity is actually better than induced by pertussis
infection” (p.1426). Therefore, vaccines do provide immunity to those who receive the vaccine.
PERTUSSIS 17.
However, it is important to emphasize the need to correctly follow the time frame for pertussis
shots and boosters.
Scientific data has also been collected showing the pertussis vaccine losing its protective
strength overtime, suggesting a need for booster shots. Rittle (2010) stated “the most dramatic
increase in pertussis incidence has been among adolescents and young adults and indicated that
this was due to the effects of waning of vaccine-induced immunity effectiveness” (p. 285).
Public Broadcasting Service (PBS, 2012) even stated “A full 92 percent of adults are no longer
inoculated against the disease — in large part because most Americans don’t know that a new
booster exists”. This statement further emphasizes the need for public education on the need for
booster shots. With 92% of adults not getting the correct booster shots, it is no wonder pertussis
remains an epidemic throughout many parts of the country. PBS (2012) further stated the
common vaccines given for pertussis, which are usually in combination with tetanus and
diphtheria vaccinations, “typically offer high levels of protection within the first two years of
getting vaccinated, but then protection decreases over time. This is known as waning immunity.
In general, DTaP vaccines are 80-90 percent effective. Our current estimate is that Tdap
vaccination protects 7 out of 10 people who receive it”. The need for booster shots, combined
with the waning immunity, would explain why cases of pertussis drastically decreased after the
introduction of the vaccine but then began to steadily increase again.
Gaps in Knowledge
Although there is not a clear cause for why pertussis cases are steadily increasing, much
research is showing there is an obvious link between lack of vaccinations and booster shots
leading to the spread of pertussis. Public education about the need for initial vaccinations, and
the need for booster shots, is necessary to slow the rate of pertussis.
PERTUSSIS 18.
Much more research is needed to understand the rising rates of pertussis. Further studies
into the vaccine itself are needed. PBS (2012) stated “Among kids who get all five doses of
DTaP on schedule, effectiveness is very high within the year following the fifth dose — at least 9
out of 10 kids are fully protected. There is a modest decrease in effectiveness in each following
year. About 7 out of 10 kids are fully protected five years after getting their last dose of DTaP
and the other 3 out of 10 kids are partially protected — protecting against serious disease”.
Perhaps further research into the vaccine will lead to a more effective vaccine throughout the
entire five years and decrease the need for frequent booster shots.
Further Epidemiological Research.
Overall, there is much research about the epidemiology behind pertussis. However, with
the growing rates of pertussis, it will be important to continue to research where pertussis cases
are increasing and what sexes, races, and ages are at most risk for pertussis. As increased
education is provided to the public, it will be interesting to see how public education about the
vaccine affects the number of pertussis cases. Also, with many states offering free pertussis
vaccines with hopes to slow down epidemics, epidemiological research will be needed to see
how free vaccinations affect the rates of pertussis.
Conclusion
Pertussis is a complex disease which can affect people of all ages. In order to stop the
spread of pertussis, public health departments must have not only an understanding of the
science behind pertussis, but also knowledge pertaining to all the factors involved with pertussis.
With the continued involvement of public health departments, and the cooperation of the public
to get properly immunized, there is hope that someday pertussis will be eradicated
PERTUSSIS 19.
References
Cagney, M., Macintyre, C.R., Mcintyre, P., Puech,M., & Giammanco, A. (2006). The
seroepidemiology of pertussis in Australia during an epidemic period. Epidemiology and
Infection, 134(6), 1208-1216.
Carmon, M., & Spratling, R. (2010). Pertussis: An overview of the disease, immunization, and
trends for nurses. Pediatric Nursing, 36(5), 239-243.
Cherry, J. (2005). The epidemiology of pertussis: A comparison of the disease pertussis with the
epidemiology of Bordetella pertussis infection. Pediatrics, 115(5), 1422-1427.
Centers for Disease Control and Prevention. (2005). Pertussis: United States, 2001-2003.
Retrieved from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5450a3.htm
Centers for Disease Control and Prevention. (2012a). Pertussis. Retrieved from
http://www.cdc.gov/pertussis/
Centers for Disease Control and Prevention. (2012b). Vaccines and immunizations: Pertussis.
Retrieved from http://www.cdc.gov/vaccines/pubs/pinkbook/pert.html
Crose, J., Cruz, R.M., & Tornabene, S.V. (2012). Pertussis presenting as hoarseness in an adult.
Ear, Nose, & Throat Journal, 91(2), 22-24.
Fishman, D.N., Tang, P., Hauck, T., Richardson, S., Drews, S.J., Low, D.E., & Jamieson, F.
(2011). Pertussis resurgence in Toronto, Canada: A population- based study including
test-incidence feedback modeling. BMC Public Health, 694 (11), 1-10.
Hockenberry, M.J (2003). Nursing care of infants and children. D.Wilson, M.Winkelstein, N.
Kline (Eds). St. Louis, MO: Mosby.
PERTUSSIS 20.
March of Dimes. (2012). Sounds of pertussis. Retrieved from
http://www.soundsofpertussis.com/talk-to-your-doctor-today.cfm
McCance, K.L., & Huether, S.E. (2006). Pathophysiology: The biologic basis for disease in
adults and children (5th ed.). St. Louis, MO: Mosby.
Public Broadcasting System. (2012). Whooping cough outbreak: Top 10 things you should know.
Retrieved from http://www.pbs.org/newshour/rundown/2012/08/whooping-cough-
outbreak-top-10-things-you-should-know.html
Rittle, C.(2010). Pertussis-The case for universal vaccination. Journal for Specialists in Pediatric
Nursing, 15(4), 282-291.
Saadi, A.T., Blackwell, C.C., Essery, S.D., Raza, M.W.,el Ahmer, O.R., MacKenzie, D.A.,…
Keeling, J.W.(1996). Developmental and environmental factors that enhance binding of
Bordetella pertussis to human epithelial cells in relation to sudden infant death syndrome.
FEMS immunological and medical microbiology, 16(1): 51-59.
SuMi, K., HyunSoo, O., OkKyung, H., Moon-Hyun, C., WhaSook, S. (2010). Susceptibility and
factors of pertussis vaccination adherence in Korean health care workers. Am J Health
Behavior, 34(1), 45-53.
Wisconsin Department of Health Services. (2005). Pertussis. Retrieved from
http://www.dhs.wisconsin.gov/immunization/pertussis.htm
World Health Organization. (2012). Pertussis. Retrieved from
http://www.who.int/immunization_monitoring/diseases/pertussis/en/