1.What are the challenges in combating emerging and reemerging diseases? 2.Discuss some of the examples given your book. 3.Some steps we can take to prevent an outbreak of the diseases. Emerging Infectious Diseases LEARNING OBJECTIVE 14-19 List several probable reasons for emerging infectious diseases, and name one example for each reason. Emerging infectious diseases (EIDs) are diseases that are new or changing, are showing an increase in incidence in the CHAPER 14 . Princlples of Disease and Epidemiologg 411. recem past, or show a potential to increase in the near future (see Chapter 1). An emerging disease can be caused by a virus. a bacterium, a fungus, a protonoan, or a helminth. About 75% of emerging infectious diseases are zoonotic, mainly of viral origin, and are likely to be vecton borne. Several criteria are used for identifyiog an HiD, For exam. ple, some diseases present symptoms that are cleady disinctive from all other diseases. Some are recogrized because improved diagnostic techniques allow the identification of a new parbogen. Others are identified when a local disease becoines widespread, a rare diskase becomes common, a mild diseas becomes more severe, or an increase in life span permits a alow. disease to develop. Examples of emerging infectious diseases are listed in Table 14.5 and described in the boses in Chapters 8 and 13 (pages 218 . and 367 ) . A variety of factoss contribute to the emerpence of nicw infectious diseases: - New srains, such as E. coli 0157417 and avian influcaza (H5N1). may result from genetic recoenbination between organisms. - A new serovar, sich as Videio dolerae O139, may resulh from changes in or the evolution of existing microorga niams. - The widespread, and sometimes unwarranted, use of antiblotics and pesticides encourages the growth of mote resistant populations of microbes and the vectors (mosquitoes, lice, and eicks) that carry then. - Clobal warming and changes in weather patterns mayy increase the distribution and survival of reervairs and vectors. resulting in the insrodaction and dissemination of diseases. such as malaria and Handavines palmonary syndrome. - Known diseases, such as Zika virus discase, chikungganya. dengue, and West Nile encephalitis, may spread to new geographic areas by modern transportation. This was less likely 100 years ago, when tavel took vo long that infected traveless either died or recovered during passage - Insect vectors transported to new areas can transmit infections brought by human traveles. The African yellow fever mosquito. Aedes aedppli came to the Anecicas with the first European explorers. Yellow ficver yinus was also. brought to the Americas with those first exploren, and A aegypti transmitted the disease to native populations and immigrants alike. The A sian eiger mosquito, A . allopitrie, was. inadvertently brought to Texas on a cargo ship from lapan in 1985. Both Ades ypecies are now estaklished throughout the southem and southwestern stares..

1. 1.What are the challenges in combating emerging and reemerging diseases?
2.Discuss some of the examples given your book.
3.Some steps we can take to prevent an outbreak of the diseases.
Emerging Infectious Diseases LEARNING OBJECTIVE 14-19 List several probable reasons for
emerging infectious diseases, and name one example for each reason. Emerging infectious
diseases (EIDs) are diseases that are new or changing, are showing an increase in incidence in
the CHAPER 14 . Princlples of Disease and Epidemiologg 411. recem past, or show a potential
to increase in the near future (see Chapter 1). An emerging disease can be caused by a virus. a
bacterium, a fungus, a protonoan, or a helminth. About 75% of emerging infectious diseases are
zoonotic, mainly of viral origin, and are likely to be vecton borne. Several criteria are used for
identifyiog an HiD, For exam. ple, some diseases present symptoms that are cleady disinctive
from all other diseases. Some are recogrized because improved diagnostic techniques allow the
identification of a new parbogen. Others are identified when a local disease becoines widespread,
a rare diskase becomes common, a mild diseas becomes more severe, or an increase in life span
permits a alow. disease to develop. Examples of emerging infectious diseases are listed in Table
14.5 and described in the boses in Chapters 8 and 13 (pages 218 . and 367 ) . A variety of factoss
contribute to the emerpence of nicw infectious diseases: - New srains, such as E. coli 0157417
and avian influcaza (H5N1). may result from genetic recoenbination between organisms. - A
new serovar, sich as Videio dolerae O139, may resulh from changes in or the evolution of
existing microorga niams. - The widespread, and sometimes unwarranted, use of antiblotics and
pesticides encourages the growth of mote resistant populations of microbes and the vectors
(mosquitoes, lice, and eicks) that carry then. - Clobal warming and changes in weather patterns
mayy increase the distribution and survival of reervairs and vectors. resulting in the insrodaction
and dissemination of diseases. such as malaria and Handavines palmonary syndrome. - Known
diseases, such as Zika virus discase, chikungganya. dengue, and West Nile encephalitis, may
spread to new geographic areas by modern transportation. This was less likely 100 years ago,
when tavel took vo long that infected traveless either died or recovered during passage - Insect
vectors transported to new areas can transmit infections brought by human traveles. The African
yellow fever mosquito. Aedes aedppli came to the Anecicas with the first European explorers.
Yellow ficver yinus was also. brought to the Americas with those first exploren, and A aegypti
transmitted the disease to native populations and immigrants alike. The A sian eiger mosquito, A
. allopitrie, was. inadvertently brought to Texas on a cargo ship from lapan in 1985. Both Ades
ypecies are now estaklished throughout the southem and southwestern stares. And both are
vectors for Zkea, hikangunya, dengue, and West Nile viruses - Previously unrecognized infection
may appear in individuals living or working in regions undergoing ecological changes PARt
THREE Internotton besween Mikerebe and Hest. brought abour by natural diatec, omeruxtion
wars and expanding human settkement. In Califomia, the incidence of coccidioidomyeostr
incmased tonfold following the Northrid? eanhquake of 1994. Workers cke aring Socth.
American forests afe now contracting Vancruclan hemorrhasic fexcr. - Even animal control
meavuros man affect the incidence of a. disease. The incacase in lyme disease in recent years
could be due to rising decr populaticins sealting ftom the killing of deet predatars. - Failures in
public health meanumes may be a ceiznibuting. factor to the emergance of presicasly controlled
infections. For example, the falluse of adults to gat a diphtheria booster vaccination led 10 a

2. diphthenia epidemic in the newby independent repuhlics of the former Soviet thnion in the 1990 .
- Bioterrorism, the use of pulhogens ot taxinsi to produce deathand desease in humans, animak,
or planes as an act of vicience and intimidation, is another Exctor that could affot the acturnence
of ementing infoctious diveses. The pathogens Whi patients who were outureposise for c.
defncene What is the mest liliely mode of trandmisulen, and now can transmission be prevented?
CHAPTER 14 Principles of Disease and Epidemiology 4: or toxins can be disseminated through
aerosolization, food, human carriers, water, or infected insects. Recent examples of bioterrorism
are discussed in the Big Picture in Chapter 24 (pages 696-697). The CDC, the National Institutes
of Health (NIH), and the World Health Organization (WHO) have developed plans to address
issues relating to EIDs. Their priorities include the following: 1. To detect, promptly investigate,
and monitor emerging infectious pathogens, the diseases they cause, and factors that influence
their emergence 2. To expand basic and applied research on ecological and environmental
factors, microbial changes and adaptations, and host interactions that influence EIDs 3. To
enhance the communication of public health information and the prompt implement ation of
prevention strategies regarding EIDs 4. To establish plans to monitor and control EIDs
worldwide Because of the importance of emerging infectious diseases to the scientific
community, the CDC publishes a monthly journal called Emerging Infectious Diseases.