Infectious Diseases

Question 1

Infectious Disease Mechanisms

Answer 1

chain of infection occurs when the infectious agent is conveyed
from a reservoir host through a direct or indirect mode of
transmission to a susceptible host.
* Disrupting the links of the chain between each of its component parts is a potential source of transmission prevention.

Question 2

Infections Agent

Answer 2

• consists of a virus, bacteria, fungus, parasite, or prion.
• The agent resides in a reservoir host.
• The natural habitat of the agent and can be environmental, human
  or animal.

Question 3

Human Reservoirs

Answer 3

• Humans are reservoirs for many infectious agents.
• For some contagious diseases, humans can be the only reservoir

Question 4

Zoonosis

Answer 4

• Refers to the transmission of an infectious agent from a vertebrate animal host to humans.
• Rabies is one example
• account for 75% of emerging infectious diseases

Question 5

One Health approach

Answer 5

Increasing awareness of the interconnectedness of humans, animals, and the environment in the transmission of infectious diseases has led to the
development of a One Health approach

Question 6

Means of Transmission: Direct

Answer 6

• Occurs when the pathogen is passed via direct contact from one person to another.
• Large droplets that are excreted by a person who is a reservoir through the pathway of sneezing, coughing, or talking

Question 7

Means of Transmission: Indirect

Answer 7

• Can occur through airborne, vector-borne, or vehicle-borne means.
• Airborne transmission occurs when infectious agents are carried via droplet
  nuclei and can remain in the air for long periods.
• Tuberculosis (TB)

Question 8

• Vectors carry infectious agents

Answer 8

• Mechanical means
• Insects carrying the agent on their feet
• Biologic means
• Vector such as an insect must process the agent biologically before the agent becomes
  infective to humans.
  -can happen
• Vehicle-borne transmission can occur via food, water, biologic products, or
  inanimate objects

Question 9

Susceptible Host

Answer 9

• Factors can influence both the likelihood of an exposed person being infected, as well as the severity of the infection

Question 10

Stigma

Answer 10

Consider the stigma of an infectious disease.

Question 11

Human Immunodeficiency Virus
Description and Definitions
* Zoonotic transmission

Answer 11

• HIV-1, with its four subtypes, originated from simian immunodeficiency virus
  (SIV) strains in apes and is the primary contributor to the current global HIV
  epidemic.
• HIV-2 originated from an SIV strain in sooty mangabey monkeys and is less
  common but has demonstrated a greater resistance to certain antiretroviral
  agents.

Question 12

HIV stage 1

Answer 12

• Highly infectious.
• Within 2-4 weeks of initial exposure, the infected individual may experience
  flulike symptoms, such as fever, headache, chills rash, sore throat, fatigue,
  mouth ulcers, and enlarged lymph nodes

Question 13

HIV stage 2

Answer 13

• The virus is active and transmissible but reproduces at low levels so the
  individual has few symptoms.
• Without treatment, this stage may be short or last up to a decade
  -can be prevented with meds

Question 14

HIV stage 3

Answer 14

• Acquired Immunodeficiency Syndrome (AIDS).
• Symptoms include weakness, weight loss, chills, fevers, sweats, and swollen
  lymph glands.
• AIDS is diagnosed when a person’s CD4 cells falls below 200 cells per cubic
  millimeter of blood or if the person develops one or more opportunistic infections commonly associated with HIV,
  -can cause death

Question 15

Human Immunodeficiency Virus
Signs and Symptoms

Answer 15

• Lymphadenopathy
• Infants can experience oral candidiasis, failure to thrive, and developmental delay.
• Children with HIV may develop pneumonia, bacterial infections, wasting syndrome, esophageal candidiasis, HIV encephalopathy, or other AIDS
  defining conditions

Question 16

Human Immunodeficiency Virus Diagnosis

Answer 16

with blood samples using
enzyme immunoassays that detect antibodies and antigens.
* Rapid testing with enzyme immunoassays that detect antibodies alone can also be used but can miss infection in the earliest stages

Question 17

Human Immunodeficiency Virus
Course and Prognosis

Answer 17

• If left untreated, HIV infection almost universally progresses to AIDS
• Mortality most often occurs due to opportunistic infections that the body’s
  compromised immune system is unable to fight.
• The success of cART has meant that many people with HIV are
  living long term

Question 18

Human Immunodeficiency Virus
Neurocognitive Disorder

Answer 18

-An additional co-occurring health condition that can develop as people age with HIV is HIV-associated neurocognitive disorder (HAND).
* Asymptomatic neurocognitive impairment (ANI)
* HIV-associated mild neurocognitive disorder (MND)
* HIV-associated dementia (HAD)

Question 19

Symptoms of HAND

Answer 19

• Difficulty reading, performing complex tasks, or maintaining concentration may be
  experienced.
• Motor problems
• Apathy, lethargy, loss of sexual drive, and diminished emotional responsiveness and
  sadness may also be experienced.

Question 20

Human Immunodeficiency Virus
Mental Health

Answer 20

Depression and anxiety symptoms are relatively high in people with HIV.
* Major depression, bipolar disorder, schizophrenia,

Question 21

Tuberculosis

Answer 21

• infectious bacterial disease.
• Mycobacterium tuberculosis is the source of this disease and is present in the sputum of actively infected people.
• TB most commonly affects the lungs by causing bronchial inflammation and lung
  tissue infection and destruction that eventually results in pulmonary scar tissue
  that impedes oxygen and carbon dioxide diffusion

Question 22

Tuberculosis
Etiology

Answer 22

The cause of TB is the transmission of M tuberculosis via cough aerosol
* The bacteria are typically carried in droplets that are released when an infected person coughs and these droplets are inhaled into the alveoli of another individual.
* Droplets with the TB bacteria can remain suspended in the air for several hours.
* Once the bacteria enter the host, an inflammatory response is triggered.
* The immune system targets and attacks the invaders

Question 23

Tuberculosis
Signs and Symptoms

Answer 23

• Latent TB is an immune response to stimulation of M tuberculosis without
  active TB.
• These individuals do not have any symptoms and do not feel ill but will test positive for TB
• fever, drenching night sweats, weight loss, and fatigue/weakness.
  -cough, chest pain, hemoptysis (coughing up blood), and
  shortness of breath.

Question 24

Tuberculosis
Course and Prognosis

Answer 24

• Most people who receive a timely diagnosis and are treated with first-line antibiotics for 6 months will recover.
• If left untreated, mortality rates are very high

Question 25

Tuberculosis
Medical/Surgical Management

Answer 25

• There is no vaccine for pulmonary TB.
• The current medical treatment consists of prevention and treatment using an
  oral medication regime.
• The medication regime for TB requires consistent medication for a minimum of 6
  months and often up to 2 years,