Emerging Infectious Diseases Flashcards
In what ways does “change” impact disease spillover?
- The main point of the article is that as time goes by, we develop new vaccines or treatments, and we feel that we are making good progress. With this progress we become complacent and start to regress our efforts until the newly evolved and developed strains of disease are overpowering the progress we’ve made. So much is always changing in the demographics, financial inequalities, international travel, immigration, environmental standards, and technological advances that there is a constant need for updating current methods and maintaining focus on the goal of complete disease eradication.
- Procrustean measures are measures that are applied universally without regarding individual variation. This obviously does not work in infectious diseases as there is no ‘one size fits all’ method to treating disease. Individuals vary based off all the many social determinants of health including race, susceptibility, genetics, presence of other diseases, and many more. They also vary on a societal level when one accounts for all the variation between communities in geography, climate, herd immunity, demographic trends, and many more. Individual people require individual and specifically tailored prevention and treatment efforts.
Define emerging disease
An emerging disease is one that has not previously infected humans or is new to a certain location
Most emerging diseases are zoonotic
Influenza is a recurring emerging disease
Monitored through infectious disease surveillance
Define Spillover
The moment when a pathogen begins causing disease in a new host
Becomes an emerging disease in that host
Define Amplifier
Species that sheds enough virus to infect another species that requires a higher infectious dose
Define Cluster
A disease cluster is an elevated level of cases within a geographic area at approximately the same time
Define contact tracing
Identify infected persons, and interview those who may have come in contact with them
Watch those who have been contacted and determine if they become ill
Hume Field’s role in Hendra virus discovery
Hume Field, a local graduate student, begins investigating.
“The virus hunter is a field biologist, possibly with advanced training in human medicine, veterinary medicine, ecology, or some combination of those three- a person who finds fascination in questions that must be answered by catching and handling animals.” - Spillover
Knew that it was a paramyxovirus and that someone had recently found a new paramyxovirus in rodents
Started trapping animals and testing for antibodies, looking for the reservoir
Didn’t find anything… could it be a problem with seasonality? Testing in March/April, Drama series had gotten sick in September
A man living 600 miles north had been sickened once, then a year later experienced seizures and died. Getting even worse- now it can infect and remain latent.
From these and other stories start piecing together the idea that close contact with fluid is required for infection
A network of people in Australia called “carers” who recuperate injured wildlife, many work with bats
Field starts testing bats being held by carers
Found antibodies in grey-headed flying fox, spectacled flying fox, little red flying fox
Tested old samples from years before of bats and found Hendra- probable reservoir
Role of biogeography in understanding Hendra virus
Meeting of experts decides to investigate the biogeography of the virus – it was found in areas hundreds of miles apart. Had to be something that existed at both places or could travel- led to a focus on birds and bats.
In Queensland, Australia the sky is thick with bats in places. They are everywhere.
How studying bat carers helped figure out the transmission of Hendra
A network of people in Australia called “carers” who recuperate injured wildlife, many work with bats
Field starts testing bats being held by carers
Found antibodies in grey-headed flying fox, spectacled flying fox, little red flying fox
Tested old samples from years before of bats and found Hendra- probable reservoir
Some guidelines for responding to new pandemics (slides 21 and 22)
Identify clusters -> Contact trace -> Look for clues in reservoirs, biogeography, transmission routes, etc.
Use mild measures if mortality similar to seasonal influenza (0.1%)?; use severe measures if >2% of deaths in middle age groups?
Difficult to assess % of cases that are serious, because those with mild cases don’t go to the doctor = not reported
Conduct serological studies between seasons in tropic areas
Surveillance requires advanced planning and infrastructure (in new pandemic take advantage of existing systems)
Communication with the public and international cooperation critical
