This document discusses the resurgence of infectious diseases. It covers topics like HIV/AIDS, how it originated and spreads, and treatments developed. It also discusses other emerging viruses like Ebola, factors that lead to new diseases, and challenges from antibiotic-resistant bacteria and influenza. Public health responses are outlined to help address surveillance, vaccines, and reducing inappropriate antibiotic use. Bioterrorism is also mentioned as a threat that utilizes similar response approaches.

1. Copyright © 2021 by Jones & Bartlett Learning, LLC an Ascend Learning Company. www.jblearning.com.
CHAPTER 10
The Resurgence
of Infectious
Diseases

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©
2021
by
Jones
&
Bartlett
Learning,
LLC
an
Ascend
Learning
Company.
www.jblearning.com
HIV/AIDS
 Was first recognized in the U.S. in 1981
 Is now a worldwide killer
 Is caused by a retrovirus
 Attacks the immune system
 Screening test recognizes antibodies.
 We can measure viruses in the blood.
 Now many drugs are available but no cure.

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2021
by
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Bartlett
Learning,
LLC
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Ascend
Learning
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www.jblearning.com
HIV/AIDS Transmission
 Sexual contact:
– Homosexual
• Most common in U.S.
– Heterosexual
• Most common around the world
 Sharing needles:
– Intravenous drug use
– Medical use of unsterile needles

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Ascend
Learning
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www.jblearning.com
HIV/AIDS Transmission (cont.)
 Mother to infant
– Prenatal or during birth
– Breastfeeding
 Blood transfusions
– No longer in the U.S.
 Circumcision helps protect men against contracting HIV from women, but it
doesn’t protect women from contracting it from men.

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Learning,
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Ascend
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HIV/AIDS Treatments
 Highly active antiretroviral therapy (HAART), a drug combination, led to
dramatic improvements in survival rates.
– Reduces viral load to undetectable levels in blood and body fluids
– Encourages infected people to be tested and treated, preventing transmission
 Fusion inhibitors
 Integrase inhibitors

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Learning,
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Ascend
Learning
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www.jblearning.com
Where Did HIV Originate?
 Probably originated in Africa
 Transmitted cross-species from monkeys
or apes
 Spread in human populations due to disruption of traditional lifestyles
 Spread to Western countries due to changing patterns of sexual behavior and
international travel

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Learning,
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Ascend
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Other Emerging Viruses
 Ebola
 Monkeypox
 Zika
 Other hemorrhagic fevers
 West Nile virus
 SARS

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Learning,
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an
Ascend
Learning
Company.
www.jblearning.com
Factors That Lead to Emergence of New
Infectious Diseases
 Human activities that cause ecological damage and close contact with wildlife
 Modern agricultural practices
 International travel
 International distribution of food and exotic animals
 Breakdown of social restraints on sexual behavior and intravenous drug use

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Learning,
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an
Ascend
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www.jblearning.com
Influenza
 Influenza is an RNA virus like HIV.
 Virus is constantly mutating.
 Vaccine must be changed frequently.
 New lethal strains appear periodically.
 Epidemic of 1918–1919 killed 20 million to 40 million worldwide.
 Bird flu and H1N1 are concerns.

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New Bacterial Threats
 Legionnaires’ disease
 Lyme disease
 Group A streptococci
 E. coli O157:H7 in food
 Antibiotic resistance
– From improper medical use
– Use in agriculture
– MRSA

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Tuberculosis
 TB is the leading cause of infectious-disease death worldwide.
– One third of the world population is infected.
 There was a resurgence in the U.S. in the early 1990s.
 People with HIV are at much higher risk.
 TB is transmitted by aerosol.
 Fatality rate is 50% for untreated TB.

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Tuberculosis (cont.)
 Antibiotics are effective but must be taken for several months.
 Improper use of antibiotics leads to resistance, including multidrug resistance.
– Then, mortality rate can exceed 50%.
 Directly observed therapy works.
– It is the best approach for preventing antibiotic resistance.
 In 2007, the CDC revised its requirements for overseas medical screening of
applicants for immigration to the U.S.

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Prions
 Creutzfeldt–Jakob Disease (CJD)
– Sporadic CJD is most common.
– CJD usually appears in later life.
– Bovine spongiform encephalopathy (BSE) or “mad cow disease” has a history in
Britain.
– New variant of CJD (vCJD) in the UK in younger people is thought to be caused by
eating infected beef.
– Regulations have been tightened on animal feed.
 Gerstmann–Straussler–Scheinker syndrome
 Fatal familial insomnia
 Kuru

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Public Health Response to Emerging Infections
 Global surveillance
 Improved public health capacity
 Veterinary surveillance
 Reduction of inappropriate use of antibiotics
 Institute of Medicine recommendations:
– New vaccines
– New antimicrobial drugs
– Measures against vector-borne diseases

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Ascend
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www.jblearning.com
Threat of Bioterrorism
 Approach to bioterrorism is the same as that for natural disease outbreaks.
 Bioterrorism will probably first be recognized by surveillance.
– First signs of an attack are likely to be seen by physicians and hospital emergency
room staff.
 It is best defended against by the same methods as natural outbreaks.

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Ascend
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www.jblearning.com
Discussion Question 1
 Consider the spread of the following emerging infectious diseases, using the
chain of infection: E. coli O157:H7, Lyme disease, Ebola virus, hantavirus,
influenza, tuberculosis, vCJD.
 For each disease, explain how the chain of infection can be interrupted.

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Discussion Question 2
 What are the reasons for the rapid emergence of AIDS as a worldwide
epidemic?

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Discussion Question 3
 What are three public health measures that could reduce the probability that
bacteria will develop resistance to antibiotics?

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Ascend
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Discussion Question 4
 Visit the website of the National Institute of Allergy and Infectious Diseases,
www.niaid.nih.gov.
 Under “News & Events,” review the news releases over the past year.
 On what diseases has the Institute released news about progress in research?

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Learning,
LLC
an
Ascend
Learning
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www.jblearning.com
Discussion Question 5
 Visit the website of the CDC’s journal, Emerging Infectious Diseases,
www.cdc.gov/ncidod/eid.
 What emerging diseases are discussed in the current issue?