The Middle East & North Africa (returning to) being the bastion of civilisation is fascinating. Supposedly, the Rash hit Europe via a boatload of refugees (Patients 0) landing in Spain. Although it's never stated, they are presumed to be from North Africa. But, I set the story Róisín mentioned in a desert, thinking that the conditions would be too hot and arid for trolls, and No. Africa certainly has plenty of those conditions.
(Although I must admit my story is NOT exhaustively researched; I left actual engineering to Minna-esque hand-waving. Fun fact - the first drafts of the story were set in the Middle East, because I had a vague idea of our intrepid crew out exploring post-mission and figured California or Mongolia was too blimmin' far even for crack fic.)
Iran is beheld (on "our" side) as the most capable of all middle eastern states to keep most of their pre-Rash assets functioning. Close up to it were (mainly this one) Algeria, Syria, Cyprus, the (Greek) Creta island and maybe several enclaves across northern Africa and the Greek/Turkish isles in the Agaean sea that parts both nations.
The criteria were:
1.: Military Preparedness: Is the nation dependent on foreign powers for it´s protection or is it a N. Korea grade fortress?
> Iran, Algeria scored well here. The former is renowned through media and the web as a gun-toating, gargantuan post-revolution 1979 state. This credibility is partially true and looking into the wikipedia about the armed forces of Iran, the nation has militarised itself heavily, with the large regular army backed by legions of paramilitary citizen militias. This´d mean that Iran posesses more the abillity to combat external threats (the spread of the Rash, suddenly aggressive neighbors) and internal threats (the spread of the Rash, civil uprisings within the nation) with violent force.
> The latter, Algeria, is also on the world stats for their military size-- which does indeed give them the abillity to profit from it massively, although why? Algeria only needs to move troop to protect it´s urban north at the most, with the south only needing (already owned by Algeria) mobile armor to protect the nation from the spread of Rash by refugee escapees from states where the situation is at worst and the loss of oil and uranium fields.
2.: Geographical Position: Self-explanatory.
> Iran has the greatest trait of being a hill-dominated nation, which means that unlike in the USA and European states, inter-city spread of the Rash goes either slower or is easy to be blocked if the Iranian army simply blocks highways.
> Algeria only needs to protect their vital, urban north with it´s population-- and it is small in size. The south is a vast "wasteland" and sub-saharan region, that does not need a massive military presence to remain safe.
3.: Government Stance: Quarantine or Death-Squads?
> Flash-backs to the SSSS scene, so spoiler alert!
. . . A council of people (that familiar round table) discuss the situation. It is well noticeable: Nobody is happy and is barely willing to even consider further trying to treat the Rash. Still, the supposed scientists urge that they need more time for the development of a cure-- although they get 2 weeks granted, a lenghty amount of time for the fact that a disease is ravaging the nation by each hour.
Denmark, Sweden, Finland, Iceland and Norway are benevolent democracies, built upon the foundations of human rights and liberty.
Iran and Algeria are critical states in that question. This given to the fact (despite that Iran and Algeria are democracies) that both these nations are extremely authoritarian. Alone the Iranian or Algerian leadership gaining notice of their intelligence services reporting that a brutal, new disease is ravaging and spreading throughouth the world, sirens would ring well before both states would go at a "hug and treat" the sick action. I would not be surprised if smaller Rash outbreaks would have the sorry affected "made to dissapear" by shady death-squads or government-loyal troop. Plus, Iran and Algeria-- with their authoritarianism can exhert control over the media to blot out massive human rights abuses and military action against the spread of the Rash, even if it means thousands must be "secured" and hospitals be locked up and set ablaze to prevent the Rash from spreading.
There were several more criteria, such as the presence of strategic minerals like oil and industrial centers, but I have already mentioned it.