11.1 Emerging & re-emerging diseases Flashcards
Emerging infectious diseases are ?
newly identified in a population
examples of emerging infectious diseases ?
- ebola
- MERS-CoV
- SARS-CoV-2
Re-emerging infectious diseases are ?
already known that have been previously under control but are reoccurring
Infectious disease emergence has 2 main steps which are what ?
- an agent is introduced into new host population
- agent is established & transmitted within new host population
Reasons for emergence of new infections ?
- microbial adaptation & change
- ecological changes
- human behaviour
- demographics e.g. poverty
- technology & healthcare
- travel, trade & industry (e.g. antibiotics in farm animals)
- public health measures e.g. sanitation
- lack of vaccination programs
- susceptibility to disease
Why is microbial adaptation and change a reason for emergence of new infections?
Microbes continually adapt to environment, they may adapt to evade immune system or be provided with new ability to invade human cells.
They could develop AMR (antimicrobial resistance)
They could change, making vaccines less effective
Examples of ecological changes that is a reason for emergence of new infections ?
- due to urbanisation, deforestation humans may come into contact with animals increasing exposure
- climate change = provide more favourable conditions for vectors to carry disease
- floods
Why is urbanisation , deforestation a reason for emergence of new infections?
- Humans may come into contact with animals which can increase risk of human exposure to infectious disease
Why is climate change a reason for emergence ?
might provide more favourable conditions for vectors to carry disease
Why is human behaviour a reason for emergence of new infections?
- Sexual contact, drug use, outdoor activities = increased exposure (which can spread rapidly in populated areas)
Why is demographics a reason for emergence of disease ?
Poverty, social inequality, politics
Why is technology & healthcare a reason for emergence of new infections?
new procedures & medical treatments – e.g., blood transfusions, organ transplants
Why is travel, trade & industry a reason for emergence of new infections?
- International travel & transport of animals & goods – makes it easier to spread microbes & vectors worldwide
- Widespread use of antibiotics in farm animals – contribute to AMR
Why is public health measures a reason for emergence of new infections?
- Poor sanitary conditions
- hygiene
- lack of clean drinking water may provide potential for spread of existing infections and emergence of new infections
Why is lack of vaccination programs/breakdown of Public helath measures a reason for emergence of new infections? e.g. mosquito spraying…
E.g., mosquito spraying for malaria can result in emergence of previously controlled disease
Why is susceptibility to disease a reason for emergence of new infections?
Individuals may be more susceptible to infection due to low vaccine uptake, increasing age, malnutrition, disease
Many infectious diseases can be managed by Public Health measures such as…
- good hygiene practices
- immunisation programs
The UK …1…and ..2.. aim to detect possible outbreaks of disease & epidemics ASAP
- HSA (health security agency)
- PHE (public health england)
On diagnosis of a suspected notifiable disease what must be completed ?
a notification form
There is a list of notifiable diseases and causative agents notifiable to UKHSA under the Health Protection Regulations (2010).
Give some examples of notifiable diseases
- ebola
- tuberculosis
- measles
- mumps
Why is global surveillance of infectious disease so important?
- Data serves as early warning systems for impending outbreaks that could become PH emergencies
- Enables monitoring/evaluation of impact of an intervention
- Monitors epidemiology of diseases
- Guides priority setting & planning
- Diseases can be detected QUICKLY before they spread, cost lives & become difficult to control
Ebola caused by ?
ebolavirus
what does ebolavirus cause in humans ?
viral hemorrhagic fever
In ebola when do symptoms begin ?
2-3 weeks post-infection
Pathophysiology of ebola ?
- Infected fluid comes into contact with breaks in mucosa / skin
- monocytes, macrophages and dendritic cells are preferred replication sites
- these infected immune cells migrate to the lymph nodes, liver & spleen and disseminate infection
- extensive viral replication occurs in lymphoid tissue, liver & spleen
- virus triggers expression of pro-inflammatory cytokines (TNF-alpha, interleukins)
- this leads to endothelial activation, reduced vascular integrity & onset of coagulopathy due to release of tissue factor & increased NO levels
- disseminated intravascular coagulopathy leading to hepatic impairment and bleeding complications
Complications of ebola ?
hepatic impairment
bleeding to death
What leads to the hepatic impairment and bleeding to death, which are complications of ebola ?
ebolavirus triggers expression of pro-inflammatory cytokines
which leads to endothelial activation, reduced vascular integrity & onset of coagulopathy due to release of tissue factor & increased NO levels
resulting in disseminated intravascular coagulopathy
Tuberculosis = pulmonary infection with ….?
mycobacterium tuberculosis
In latent TB patients with ….1…. have no …2…. evidence of active TB
- mycobacterium tuberculosis
- clinical, bacteriological, radiographic
Groups at increased risk for developing active TB infection from latent TB
Homeless
Injecting drug users
Cigarette smokers
Immunocompromised people
examples of immunocompromised people that are at increased risk for devleoping active TB infection from latent TB ?
- people on corticosteroids
- diabetes
- end-stage renal disease
- malnutrition
- haematological malignancies
Pathophysiology of TB ?
1) Inhalation of droplets, which deposit in the alveoli
2) M. tuberculosis is engulfed by alveolar macrophages = multiplication in macrophages, kills macrophages & released.
3) Immune response activated
4) M. tuberculosis is either cleared (no TB), latent TB or progression to primary disease