wk 12- emerging infectious diseases

Question 1

what are emerging infectious diseases?

Answer 1

those that appear or re-appear in a population without warning

Question 2

emergence and reemergence is associated with geographical location y/n?

Answer 2

yes

Question 3

reasons for increased disease with developing compared to developed countries?

Answer 3

-poor sanitation
-increased population and housing density
-malnutrition
-reduced accèss to public health

Question 4

list the risk factors for the emergence of infectious diseases 10

Answer 4

antimicrobial resistance
viral mutation
host resistance or susceptibility
economic development
technological changes
environmental change
international travel
inadequate/ reduced public health measures
wars and natural disasters
lifestyle factors

Question 5

how can antimicrobial resistance contribute to emergence of infectious disease

Answer 5

antimicrobial overuse, underuse and misuse contributes to resistance through selection for infectious agents that can survive and or reproduce in the presence of the antimicrobial agent.

Question 6

how does viral mutation contribute to emergence of infectious diseases

Answer 6

changes in viral replication are called antigenic drift. This causes newly emerging viruses to become unresponsive to vaccines and antiviral meds due to the immunity being naive of the strand

mutations occur quicker in single stand viruses

Question 7

host susceptibility contributes to emerging diseases how

Answer 7

predisposing factors such as environment, climate and sanitation as well as biological and health factors increase the susceptibility to emerging infections

Question 8

how does economic development contribute?`

Answer 8

Economic development and land use leads to changes in the exposure of human hosts to native environments, animals, and insects. Changes made by humans during industrial development often select for infectious agents, by enhancing the food supply or breeding environment for the animal or insect host, and arthropod vectors.

Areas in which close contact occurs between humans and animal reservoirs facilitates transmission of zoonotic diseases.

Question 9

how do technological changes contribute?

Answer 9

Technological changes such as air-conditioning are associated with the distribution of infectious agents around internal building spaces.

Food production, processing, and preservation methods combined with cold chains mean that infectious agents in food can now be transported around the globe.

Question 10

how does climate change contribute to infectious diseases emerging

Answer 10

Climate change now sees vectors (mosquitoes, ticks, and sand flies) more widely distributed, spreading beyond previous geographical regions.

Question 11

how does international travel contribute

Answer 11

short transit times facilitate transmission of infectious agents during incubation and prodromal stages of disease

Question 12

reduced public health measures contribute how?

Answer 12

breakdown in controls by the government to prevent disease such as vaccinations (objection, lack of access, poverty, etc)

Question 13

how do wars and natural disasters contribute?

Answer 13

lead to a breakdown in infrastructure, displacement of large numbers of individuals, and subsequent poor sanitation and over-crowding. Collectively, these events result in the production of large volumes of untreated waste material, which acts as a reservoir for infectious agents and vectors

Question 14

how do lifestyle factors contribute ?

Answer 14

behaviors such as multiple sexual partners, recreational drug use support increase in infectious disease rates

Question 15

do vaccines needs to be revised and updated?

Answer 15

yes because of error-prone replication and transfer of virulence factors

which means viruses commonly have errors in its replication because there is no proof reading machinery

Question 16

what challenges does antigenic variation in influenza cause? 2

Answer 16

accumulation of subtle differences in surface antigens over time (antigenic drift - A), which lead to failure of host antibodies to recognise and bind viral antigens
rapid and major recombination events (antigenic shift - B), which result in significant changes in viral surface antigens to which human hosts are completely immunologically naïve.

Question 17

differences between antigenic drift and shift

Answer 17

change in surface antigens:
drift- minor point mutations (single nucleotides), shift- major mutations (gene reassortment)

Question 18

differences between antigenic drift and shift

Answer 18

change in surface antigens:
drift- minor point mutations (single nucleotides), shift- major mutations (gene reassortment)

classification: drift- new strain. shift- new subtype

time frame- drift- random/spontaneous. shift- large, sudden

partial immunity: drift- yes. shift- no

Question 19

vaccines and serogroups

Answer 19

vaccines are based on the most predominant serogroups for specific bacterial pathogens. Serogroups can differ between population groups

Question 20

can serogroup predominance change ?

Answer 20

yes it can, therefore surveillance is required to track circulating serogroups

Question 21

types of hosts for zoonotic diseases

Answer 21

primary (natural) host - asymptomatic carrier (bats)
secondary (transmission) host - moderate-severe illness (chickens)
Tertiary (spillover) host - severe illness (humans)

Question 22

how do zoonotic diseases come about?

Answer 22

Where animals and humans co-habitate or interact frequently, viruses have the potential to jump the host barrier. The outcome of this interaction is generally detrimental to the immune naïve human host.

Question 23

roles of healthcare worker with emerging diseases

Answer 23

comply with infection prevention and control policies and procedures
remain vigilant
remain up-to-date with controls
educate the public

these will all work to interrupt the chain of infection