Since 2012 our take on MERS is that it is either wide spread (via Hajj) and of little risk, or that its not very contagious and again of little risk. Since that time, enough epidemiological information has come forth for us to deduce from a systems analysis that
MERS-CoV has adapted itself to thrive in a very specific anthropogenic environment and outside of that (or similar) environment MERS-CoV won't sustain deadly pandemic reproduction.
Our hypothesis is that
MERS-CoV's specific adaptation is the development of a "Hard Shell". That hardened shell allows MERS-CoV to
survive in desert fecal aerosols, while also allowing it to
survive as a wet fecal fomite or aerosol, even after Islamic cleansing rituals have taken place.
Based on our analysis, a search of relevant literature showed that
others have come to a similar conclusion but a via a completely different path. (see sources below) Their path was based on determining the amount of 'flexibility' in MERS-CoV's inner and outer shells via
Protein Intrinsic Disorder Prediction. The conclusion was that of all the Corona viruses modeled, MERS-CoV showed the lowest disorder / hardest shell, and thusly was
likely fecally transmitted .
Frankly, this finding should not be surprising since other animal Coronaviruses like SARS and Feline-CoV have been documented to spread via aerosolized wet feces and aerosol dry fomite dissemination. Where as, Human cold causing Cornoaviruses are believed to be spread via sneezing and coughing.
What it means in the Desert:
The dry environmental spread of MERS-CoV is likely from a desert dwelling animal that produces very dry dung. The Camel is a prime example, its fresh dung is immediately ready for burning, and is often collected for that purpose. Its safe to assume that
people down wind of Camel (or Human) desert deposited excretia are at risk if Human disease producing MERS-CoV is present
.
For MERS to survive this kind of dust blown dehydrated environment it likely must have a hard shell.
What it means in the Hospital:
The other unusual aspect of MERS infection is that chain transmission has occurred only in hospitals in the Kingdom of Saudi Arabia [KSA]. Given the wealth, and Islamic piousness observed in KSA, this means that MERS-CoV must transmit in a western medical environment which strictly follows Islamic cleansing / palliative care requirements.
In short, KSA's wealth allows more health care workers per patient; a lot more health care worker exposure to fecal matter via close physical patient contact/care; and significant health care worker inter-exposure via common restrooms in which
no toilet paper is used to block fecal hand contact, but instead soapy hands are relied for posterior cleanliness.
For MERS to survive in this environment, it must have some resistance to soapy water aerosolization or fomite deposition degradation; again this points to a hard shell.
What it means outside of Saudi Arabia:
Given the lack of deadly MERS chain transmission outside of KSA, and our previous stated conclusions; it appears that
lethal MERS transmission requires a minimum exposure dose, one which MERS has adapted to allow KSA hospital care to deliver. Outside of a wealthy discrete healthcare environment, similar dose exposures in a distributed environment might be expected to occur in poor, high population density areas with similar cultural / religious practices.
This epidemiological analytical transformation is analogous to a MERS smart bomb on discrete target vs a cluster bomb on an area target. One might also
expect chain transmission to occur in western nursing homes.
What it means for HAJJ:
HAJJ has not yet supported deadly MERS chain transmission, but that does not rule out that it will.
Quick Conjectures:
#1 One possibility is that Camel Coronavirus in Humans is to MERS, as Feline Coronavirus[FCoV] in Cats is to Feline Infectious Peritonitis [FIP]. CATS living in high density populations often have FCoV, but only in a small percentage of cats does that infection internally mutate into the disease manifesting version which causes FIP. The disease causing version is not believed to be transmittable to other cats. Since MERS is transmissible,
a worst case reinforcing scenario would be a human MERS patient infecting a Camel with "human MERS".
#2 Camel herders are immune to MERS akin to the way in which Milk Maids were immune to SmallPox.
#3 If the in country dwell time for HAJJ pilgrims remains below the median time for symptom onset from exposure, the odds are an outbreak inside of Saudi Arabia is self limiting.
#4 The risk of a massive MERS outbreak at Hajj increases as a function of KSA's gross domestic product per (transient population) capita decreases.
Sources:
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