I'm not an expert in the field, but it seems like there are almost
countless ways in which an increased number of cases increases the
risk of further exponential growth. It's encouraging to hear that in
countries with better healthcare, death rates would likely be much
lower, but at this point, isn't it inevitable that the outbreak will
run its course as a global pandemic?
I don't think it is inevitable. The current strain has a high virulency, high mortality, but low transmissibility. It does not infect until the patient shows symptoms, but by most of that time she/he will be unable to move and spread the infection because of the 39°C degree fever. Only the people nursing the patient, e.g. family members, workers in the healthcare system, are in danger. So it spreads slowly compared to other diseases and that's why it is easy to quarantine and prevent. If it does not change attitude due to a mutation or anything else, I think we can avoid a more serious pandemic, at least I hope so.
There is an already existing model for an older strain available here: Understanding the dynamics of Ebola epidemics.
Scared carriers not yet showing symptoms sneak or force their way
across boarders to unaffected regions.
I have the impression by listening and reading news, that most of the people know nothing about ebola in Africa, or they don't really care, because they cannot read, or they have bigger problems e.g. starving. For example Sierra Leone is one of the poorest countries in the world. They cannot move so easily, because travel requires money. So I think this is possible, but unlikely. If it happens, the infected person cannot spread the disease fast, because she/he will be unable to move after showing the symptoms. So she/he can be quarantined.
Objects, food, or water touched by the infected go unnoticed until
they end up leaving the containment zone.
I think in the current case this is unlikely either. But if a food contains virions, it does not necessary cause disease, e.g. microwave oven, or long shipment - usual by fruits like banana - can inactivate it.
If it can jump from bats or monkeys, thousands of infected humans
increase points of contact to create vectors into other species,
perhaps one that will travel unnoticed far beyond the containment
Well, it needed 8 changes to fully adapt to guinea pigs. (It was possible to infect these animals, but the outcome was not lethal.) The virions contain 19kb of RNA, and the mutation rate is 2.0 x 10^-3 substitutions per site per year. Now I am not an expert of genetics (I always hated it), but as far as I understand it is possible to rougly estimate the risk based on this data. I guess it would take decades to adapt to another species, so it is not a fast process.
2013 - Animal models for Ebola and Marburg virus infections
Comparative sequence analysis of the complete genomes of the GP-adapted
EBOV and wild-type virus showed 8 nucleotide differences, which led to
5 amino acid substitutions; single amino acid mutations in NP and L
and 3 mutations in VP24 (Volchkov et al., 2000). Using a reverse
genetics approach, it was shown that VP24 had a critical role in the
pathogenesis and the amino acid changes in VP24 were essential to
achieve EBOV virulence in guinea pigs.
2013 - Ebola virus infection inversely correlates with the overall expression levels of promyelocytic leukaemia (PML) protein in cultured cells
Ebola virus belongs to the family of negative strand RNA viruses
(Mononegavirales) and together with the Marburg virus are the two
known species of the Filoviridae family 1. Electron microscopy of
Ebola virions produced in cell culture have shown them to be
pleomorphic, appearing as either 6-shaped, circular or as long
filamentous (and sometimes branched) forms with a length up to 14,000
nm and a uniform diameter of 80 nm 2. The 19 kb single-stranded RNA
genome encodes seven viral proteins: the membrane associated (matrix)
proteins VP24 and VP40, the viral glycoproteins, GP (that forms the 10
nm long peplomers) and sGP (non-structural secreted form), the
characteristic helical ribonucleocapsid that consists of the
nucleoprotein (NP), VP30, VP35 and the L-protein that forms a
RNA-dependent RNA polymerase 1.
wikipedia - Ebola virus
Sequencing of 99 different Ebola isolates from patients in the 2014
West African outbreak of Ebola showed the virus to be rapidly
mutating, with a mutation rate of 2.0 x 10-3 substitutions per
site per year making it as fast changing as seasonal influenza.
This is likely to represent rapid adaptation to human hosts as the
virus is repeatedly passed from human to human (as opposed to usually
being passed between fruit bats and only occasionally crossing over
into humans), and may pose challenges for the development of a vaccine
to the virus.
After months of the same security precautions day in and day out,
airport checkpoints, and other points of entry become lazy, and let
I don't think security works this way. Btw currently we have the technique to filter out people showing symptoms, for instance with IR detectors looking for elevated body temperature. We have e.g. ELISA for checking IgM or the presence of the virus itself in blood tests. So if these measures are needed, I think we will apply them. Currently they are not needed, according to CDC there were only 5 cases outside Africa.