Infectious Disease

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					Infectious Disease
Infectious Disease                                         Highlights and Discussion
Control of infectious disease has been a major
                                                           It is never too early to start to prevent infectious
reason for declining death rates and improved
                       th       th                         disease. One example of this is the prevention of
health during the 19 and 20 centuries.
                                                           dental caries (cavities). While there has been
Communicable diseases such as tuberculosis,
                                                           remarkable progress in the reduction of dental
polio, and diphtheria are no longer major causes
                                                           caries over the past 30 years, it is the most
of death in the United States. However, new
                                                           common disease of childhood and results in
infectious diseases and infectious agents continue
                                                           significant time lost from school and work.
to be discovered. These include Legionnaires’
                                                           Increasing evidence suggests that children are
disease, hemorrhagic fever viruses such as Lassa
                                                           infected at birth or shortly thereafter, and that
and Ebola, S. aureus and toxic shock syndrome,
                                                           treating the mother reduces the impact of disease
hepatitis viruses, HIV/AIDS, hantavirus, Lyme
                                                           on the child. Interventions for the mother include
disease, and many others. In a world where
                                                           use of xylitol gum and chlorhexidine (an antiseptic)
infectious agents can travel easily from one part of
                                                           to control growth of oral pathogens, as well as oral
the globe to the other, we continue to be faced
                                                           health instruction and dental care. It is also
with the threat of emerging and re-emerging
                                                           important to start interventions with children at a
infectious diseases. While there has been great
                                                           very early age. The American Academy of
progress in controlling communicable diseases,
                                                           Pediatric Dentistry recommends that children have
we should not be complacent.
                                                           a dental visit within six months of the eruption of
Public health activities are responsible for much of
                                                           the first tooth to initiate the lifelong interventions
the improvement in control of communicable
                                                           needed to limit the expression of disease. These
diseases. Individuals must also take action in
                                                           interventions include those that are individual-
their daily lives to stop the spread of
                                                           level, such as use of fluoride-containing products
communicable diseases. These actions include
                                                           and sealants, and those that are population-level,
handwashing, brushing and flossing, receiving
                                                           such as fluoridation of water supplies and
immunizations, using antibiotics responsibly, and
                                                           targeting individual-level interventions to
protecting sexual health by abstaining from high-
                                                           populations at highest risk of developing dental
risk sex or using barrier methods.
                                                           For many of us, another public health intervention
Section Overview                                           we participate in at an early age is immunization.
                                                           Today, immunizations protect children against
This section examines diseases that can be
                                                           diseases such as diphtheria, tetanus, pertussis,
passed from one organism to another – often from
                                                           measles, mumps, rubella, polio, Haemophilus
one human to another. It includes chapters on
                                                           influenza type b, hepatitis A and B, varicella,
 Dental Caries
                                                           influenza, and pneumococcal disease. This
 Childhood and Adult Immunization
                                                           protection against a broad range of diseases has
 Sexually Transmitted Diseases
                                                           made immunization one of the most significant
                                                           achievements of public health. However, although
 Tuberculosis
                                                           immunization coverage levels for routinely
 Meningococcal Disease
                                                           recommended childhood immunizations are at the
 Hepatitis A
                                                           highest levels ever reported, estimated coverage
 Hepatitis B
                                                           among children 19 to 35 months of age in
 Antibiotic-Resistant Infections
                                                           Washington State is only 73%. Barriers include
 Emerging Infectious Diseases
                                                           families not knowing the recommended
                                                           immunization schedules, families experiencing
The environment and access to health care are
                                                           multiple moves and multiple health care
related to infectious diseases.
                                                           providers, lack of transportation, and family
                                                           member(s) objecting to some immunizations.
                                                           Working to overcome these barriers, as well as
                                                           continuing to educate providers and parents about

The Health of Washington State                         1                                       Infectious Disease
Washington State Department of Health                                                         updated: 07/23/2002
the importance of immunizations and providing              immunosuppression. Infectious diseases can also
access to immunizations will be important.                 be present in people emigrating from areas of the
Education and access will also be important in             world where the disease is more common.
provision of immunization against influenza and            Tuberculosis cases in Washington have
pneumococcal disease in adults and those at                decreased steadily over time, and these
higher risk of disease.                                    decreases have been attributed to better living
As people age, their exposure to infectious                conditions, improved sanitation, and the
diseases can change as they participate in                 introduction of effective chemotherapy. Those
behaviors that put them at risk for disease. As            who do develop tuberculosis in Washington are
people become sexually active, they might be               more likely to be foreign-born. Between 1998 and
exposed to diseases such as syphilis, gonorrhea,           2000, 64% of all new tuberculosis cases were
or chlamydia. In general, there has been a                 among persons who were probably infected before
decrease in incidence of all these diseases since          arrival in the US. Effective intervention involves
the late 1980s and early 1990s. However, cases             prompt recognition of disease, treatment of
of primary and secondary syphilis have increased           infected individuals, and appropriate follow-up and
in recent years, primarily in men who have sex             treatment of contacts.
with men in Seattle and urban King County.                 Meningococcal disease is spread through
Gonorrhea incidence in Washington State                    respiratory secretions. In Washington, the
increased in 1999 and 2000. Chlamydia rates                incidence of meningococcus has been low except
have increased since 1996, perhaps because of a            in southwest Washington; outbreaks have been
combination of factors including more sensitive            sporadic. As with tuberculosis, people at higher
testing methods, more routine testing, improved            risk of disease can be from or travel to countries
surveillance, and a possible increase in sexual            with higher rates of disease, might have
risk-taking behaviors. These increases highlight           compromised immune systems, or be close
the continuing need to reach populations at risk           contacts of cases. People who are newly
with intensified and expanded prevention,                  aggregated in living arrangements such as college
treatment, and partner services.                           dorms are also at slightly increased risk. Public
HIV/AIDS is another disease people can become              health interventions such as immunizations are
exposed to as they become sexually active.                 recommended in some situations, but because
Unprotected sex is the primary mode of HIV                 outbreaks are sporadic, recognition of disease by
exposure in Washington, although sharing of                providers and appropriate follow-up with cases
injection equipment among drug users also                  and close contacts are typical interventions.
contributes to the epidemic in this state. AIDS            Hepatitis A, B, and C are infectious diseases that
case incidence and AIDS deaths decreased                   affect the liver. Hepatitis A is spread through
dramatically in the mid-1990s, primarily due to the        fecal-oral transmission. Hepatitis B and hepatitis
use of new antiretroviral therapies. But these             C are spread through blood and body fluids.
decreases appear to have leveled off, and AIDS             Public health interventions such as sanitation,
cases increased slightly in 2000. This increase            immunization, and access to clean injection
could be caused by a number of factors, including          equipment help control the spread of these
reaching the limits of the treatments, failing             diseases.
therapies because of treatment-resistant viral             There are additional challenges in the fight against
strains, inadequate access to and adherence to             infectious diseases. One is antibiotic resistance.
treatment, increases in HIV infections in some             Because antibiotics are crucial in the control of
groups, and improved surveillance. Increasing              some infectious diseases, the development of
HIV incidence in specific populations, such as men         antibiotic resistance is especially troubling.
who have sex with men, and the increasing                  Antibiotic resistance has been found in some
number of people living longer, healthier lives with       disease organisms in Washington, including
HIV make it important to continue to provide               tuberculosis, gonorrhea, enterococci, and
targeted prevention interventions for specific high-       Streptococcus pneumoniae. Another challenge is
risk populations and to increase their knowledge of        the emergence of new diseases such as
their serostatus.                                          hantavirus, babesiosis, and West Nile virus and
Throughout the course of their lives, people can           the potential re-emergence of once familiar ones,
be exposed to other infectious diseases. Often             such as smallpox. Our ability to travel the globe,
exposures are related to specific socioeconomic            the inroads we are making into previously
conditions, living conditions, and other health-           undisturbed environments, modern food
related factors such as substance abuse and                processing, and threats such as bioterrorism make

Infectious Disease                                     2                          The Health of Washington State
updated: 07/23/2002                                                         Washington State Department of Health
it important to develop and maintain a public
health system that can quickly recognize new
disease events so that adequate public health
responses can be mobilized.

While it is important to describe disparities in
incidence of infectious diseases to better target
populations at increased risk, it is difficult to do so
with data collected from infectious disease case
reports. Often the only data collected on
infectious disease case reports are race and
ethnicity, and these data are usually provided by
the care provider completing the case report, not
the individual with disease. Race and ethnicity
most probably are markers for more fundamental
determinants of health status such as poverty, lack
of access to quality health care, and health-care-
seeking behaviors. However, because information
is not collected about these characteristics on
infectious disease case reports, it is difficult to
determine if disparities in rates would persist were
these factors taken into account.
Even though race-and ethnic-specific disease
rates are not included in this report, other
publications illustrate that disparities do exist and
are referenced in the chapters. Additionally,
infectious disease rates tend to be higher in urban
areas, in most cases due to increased
opportunities for exposure. Rates of some
diseases, such as sexually transmitted diseases,
are concentrated among younger adults.

The Health of Washington State                            3    Infectious Disease
Washington State Department of Health                         updated: 07/23/2002