Disease Monitoring and Surveillance

Surveillance

the systemic collection, analysis, and interpretation of data in order to take action

The objective of surveillance is...

to control and or/prevent disease

Monitoring

surveillance without an intervention threshold; not taking any action!

Screening

testing apparently healthy individuals to confirm negative status and identify previously unknown infected/diseased individuals

Why would you do surveillance when disease is present?

to measure the level of disease or for case findings

Objective of case finding surveillance

to identify infected animals, flocks, or herds during a control program

Case finding surveillance should (3):

1.) use comprehensive coverage of the population

2.) be ongoing

3.) have good individual herd/animal sensitivity

Objective of surveillance to measure disease

to detect changes in the level of disease in the population

Surveillance to measure disease... (3):

1.) does not need to be continuous

2.) should be based on representative sampling to avoid bias

3.) should use a big enough sample size for precision

Why would you do surveillance when disease is absent?

for early detection of a disease or to prove a population is free from a disease

Objective of early detection surveillance

to identify disease rapidly before significant spread

For early detection, surveillance should be (3):

1.) continuous.

2.) representative of the full population

3.) sensitive to detect rare cases

Objective of freedom of disease surveillance

to provide proof that a disease is not present in the population

To prove freedom from disease, surveillance... (3):

1.) does not need to be continuous, can be intermittent

2.) may use risk-based surveillance to increase efficiency

3.) may be designed to detect high prevalence than early detection

Three animal surveillance agencies

1.) state department of agriculture (ODA)

2.) APHIS

3.) NAHLN

Two major types of surveillance

1.) passive surveillance

2.) active surveillance

passive surveillance

surveillance that uses samples and observations collected primary for another purpose

active surveillance

surveillance that uses samples and observations collected specifically for use by the surveillance program

What is an advantage to primary surveillance?

efficiency; it is simple and requires relatively few resources

What is a disadvantage of primary surveillance?

the possibility of incomplete data due to underreporting

The majority of government surveillance systems are ___________

passive

Active surveillance systems have high levels of __________ but are usually much more __________ to maintain

completeness; expensive

What type of diseases is active surveillance required for?

rare or hard to detect diseases

Example of when passive surveillance is used

antibiograms

antibiograms

generated from bacterial culture and susceptibility data; help inform antimicrobial use guidelines

Antibiograms are a periodic summary of....

susceptibility results for a selected bacteria in a defined patient population

Example of when active surveillance is used

monthly environmental sampling in the VMC using Swiffers, and culturing samples with the goal of finding antimicrobial pathogens in the hospital

Each year, flu circulates at predictable frequencies within the human population. This is an example of what temporal pattern of disease?

endemic

Bovine Leukemia virus (BLV) can be easily spread via contaminated equipment like needles, syringes, tattoo pliers, ear taggers, etc. What is the term used to describe these inanimate objects that can transmit disease?

fomites

Transmission of a pathogen through a cat bite is best described as what?

direct, horizontal transmission

What term best describes an etiologic agent's ability to cause clinical disease?

pathogenicity

What is the term used to describe testing apparently healthy individuals to confirm negative status and identify previously unknown infected individuals?

screening

Which of these options best describes why surveillance is important when a disease is absent?

a. It promotes early detection of new disease

b. It helps to establish a baseline prevalence of an existing disease

c. It helps to identify infected animals/herds when trying to control disease (case finding)

d. It detects changes in the baseline of disease prevalence

a. It promotes early detection of new disease

Which of these agencies is NOT focused on animal health surveillance in the US?

a. State Departments of Agriculture

b. NAHLN

c. USDA APHIS

d. Regional and Local Boards of Health

d. Regional and Local Boards of Health

Which of the following is TRUE regarding passive surveillance?

a. It often has complete data sets

b. It is not a huge component of government surveillance

c. It requires relatively few resources

d. It is the better option to detect rare diseases

c. It requires relatively few resources

Surveillance in bovine tuberculosis and brucellosis found what important trend in the diseases' natural history?

a. The State-Federal Cooperative program had little impact on the prevalence of bovine brucellosis

b. Foodborne zoonotic transmission is becoming increasingly important

c. The primary reservoir has transitioned from livestock to wildlife

d. Direct transmission from wildlife to livestock populations is the primary concern

d. Direct transmission from wildlife to livestock populations is the primary concern

Which of these is NOT true regarding problem-investigations?

a. They are targeted, specific investigations

b. They address a presenting complaint

c. They are essentially equivalent to the "annual physical exam"

d. They attempt to make a diagnosis for an existing problem

c. They are essentially equivalent to the "annual physical exam"

Which is NOT a reason to do a problem investigation?

a. To establish a VCPR

b. To manage a production issue

c. To address a perceived increase in disease frequency

d. To handle a population management issue

a. To establish a VCPR

Determining prevalence and incidence is part of which stage of the problem investigation?

a. Design an intervention

b. Gather information

c. Formulate a hypothesis

d. Establish a case definition

b. Gather information

Using published and on-farm evidence is helpful when completing which step/stage of the problem investigation process?

a. Design interventions

b. Gather information

c. Formulating a hypothesis

d. Establish a case definition

c. Formulating a hypothesis