Global Health Flashcards
What is a zoonotic disease?
New infectious diseases entering the human host originating from animal reservoirs
Give an example of direct zoonosis
Salmonella spp.
Give an example of indirect zoonosis
vectors, amplifying hosts
When are zoonotic diseases noticed?
Only noticed when incidence breaks through background noise in PH surveillances
What is a mild zoonotic infection?
Mild zoonotic infection entry tolerated even if incidence high R0 >1 and spread beyond local to national and international arena – true even if associated with some severe cases.
What is a severe zoonotic infection?
Severe zoonotic infection entry followed by human-to-human transmission is already established by the time the entry is noticed – cases need to be prevalent enough to breakthrough background noise at the community, PH and Healthcare settings to be noticed.
What are almost all of the emerging infections diseases an origin of?
Almost all emerging infectious diseases (EIDs) in the human population are of animal origin.
When did the SARS outbreak occur?
February 2002 - July 2003
What was the main features of SARS?
- high fever
- pneumonia
- rapid progression
What are the main features of Ebola outbreaks
- Usually a lag of 3-4 months between index case and outbreak detection
- Classic response
- Case identification – know who has Ebola
- Patient isolation with treatment and management
- Protection for response team, carers (family and professional) and those performing burials
- Contact tracing.
What type of infection is ebola
Viral haemorrhagic fever
when was ebold dicovered?
1976
What were the main points made by Peter Piot at Davod 2015?
- Developed nations in deep trouble if not prepared for infectious diseases outbreaks.
- Public Health must transcend politics and borders.
- We – the global community -were not prepared for the current outbreak of Ebola that spread across Guinea, Sierra Leone and Liberia.
- World more vulnerable to big epidemics because of population expansion, population mobility and increased intense contact between animals and people.
What are tropical diseases?
Tropical diseases tend to have emerged from non-human primates (NHP’s) and are chronic and latent and can spread at low human population density
What are temperate region diseases?
Temperate region diseases tended to arise from domestic* animals, a product of the agricultural revolution, 11,000ybp AND require dense human populations – crowd diseases.
Define crowd diseases
- Occur locally as brief epidemics and capable of persisting regionally
- Acute, 1-2 weeks individual either recovers or dies.
- Recovery associated with immune protection and epidemic quickly exhausts the susceptible people.
- Estimates suggest that populations >100,000 people are required to sustain a crowd disease eg. measles, mumps and pertussis.
Human population density + social and economic disadvantage =
Transmission hotspot
What are the most likely reservoirs of EIDs?
- Bats are mammals form the order Chiroptera and comprise the second largest number of mammalian spp.
- Bats are the only group of mammals capable of sustained flight.
- Flight enables bats to disseminate viruses and enhance interspecies
- transmission.
- Before the SARS 2002/3 epidemic bats were not known to host Coronaviruses (CoVs).
- The majority of SARS-like CoV’s were found in horseshoe bats (Rhinolophus spp.) in the Yunnan province, China.
Describe the main features of recent epidemics of zoonotic ID
- Filoviruses – Marburg, Ebola
- Coronaviruses - SARS, MERS
- Henipaviruses - Hendra, Nipah
- All are RNA viruses
- Disease severity linked to human-host immune pathology - tissue damage
- Bats are potential reservoirs of infection for all of these.
Describe the process of bottlenecks to spillover
- Three phases, each phase has multiple progressive steps each step represents a potential barrier to spillover
- Each step is essential to success
- Spillover requires alignment of all steps in space and time
- The probability of all steps aligning is small and spillover events expected to be relatively rare
- Each step is potentially a bottleneck to success
