Dr Irfan Noor is keeping a diary for the BBC News website from Pakistan's North West Frontier Province where he is working as part of a medical relief team.
Here he outlines the strategy to cater for the health needs of a population without hospitals.
Mansehra, Monday 24 October, 1500 local time (1000 GMT)
We are entering the second phase of the operation
So many hospitals and health facilities were damaged, and yet people still need the same basic day-to-day health care they needed before the earthquake.
We have lost track of these patients; people with heart disease, diabetes, and chronic illnesses. We also want full and proper care for pregnant women.
As time has passed and the number of injured and wounded has decreased, so these other health needs are coming to our attention.
Dr Noor set this photograph of people being evacuated by helicopter
Before, agencies were working on their own but now we are all working together and trying not to duplicate efforts.
The plan is for each agency to take responsibility for all the primary healthcare needs in one particular area.
But each area has a different problem. We cannot forget that there are still inaccessible places where people are injured and need to be evacuated; helicopters still go out everyday to airlift food and supplies for people in some of the remote valleys.
In the NWFP there are 25 tent villages housing some 7,080 people. Wherever we set up these tent communities we need to provide primary health care to the inhabitants so people remain there.
We have started administering measles and tetanus vaccines and Unicef are distributing high-energy biscuits.
I remember the day I first arrived here. There was nothing, people didn't even have food.
Now things are heading in the right direction. People from all over Pakistan have contributed a lot and I really appreciate their spirit.
Banna rural health centre was demolished by the quake
Although there is still much to do, it's good to know that I belong to a country where people really care for each other.
Mansehra, Wednesday 19 October, 1500 local time (1000 GMT)
Tetanus is everywhere. Eighteen cases have been reported.
Three have died already, two of them children aged nine and 10. They were unaccompanied and nobody knew who their families were. They may have been killed by the quake.
We suspect that many other children are vulnerable because they did not receive the tetanus vaccine when they were younger.
Yesterday I observed in one facility that tetanus vaccines were not being stored in cold boxes, which could render them useless. The anti-tetanus serum has to be kept at a certain temperature.
So people might be getting vaccines that have no effect.
It's a huge area and there are untrained people out there. In such chaos, people who are not properly trained will be administering the vaccine incorrectly.
Dr Noor says there are still injured people in remote districts
It's frustrating for me. We are not practising proper sterilisation. The government facilities, particularly the district hospital, is simply not adhering to minimum health standards.
They are running a makeshift operation. Even though they have the proper sterilisation equipment now, they sometimes do it the old way.
Sterilisation takes a long time and if you don't have a lot of instruments, you don't have any option. There are a huge number of patients that need treatment. Surgeries and operations are going on throughout the night.
In the Mansehra district headquarter hospital, we found hundreds of used syringes scattered all over the ground.
Here, the buildings are all damaged and the patients are outside. Sanitation is very poor. Unicef supplied anti-tetanus serum to this hospital a few days ago but the patients did not receive this until yesterday.
The patients themselves complained about it. They said they were not being treated properly. Some complained that they did not get enough blankets.
The system is overloaded.
Mansehra, Tuesday 18 October, 1540 local time (1140 GMT)
There are new challenges at every corner.
Two children died in Ayub medical complex yesterday from tetanus. Almost 30 cases have been identified. It's one of the biggest threats for the coming days.
We are investigating a plan for immunisation against tetanus. It's an unpredictable menace because of the incubation period.
Today I went to an Italian and a Saudi tent hospital; they have operation theatres and can accommodate 50 patients each.
These are really helping the situation. They are self-sufficient and the government might even ask them to go to more remote areas and provide help.
Yesterday, we went on foot to some of these areas. The population is scattered so widely, we find a few houses in need of help everywhere, it's not concentrated. They are living in total misery.
Many roads are not yet open. Many have simply been washed away by landslide. When they do open, yet more patients will come in.
It's very cold in this area at the moment. The air is frosty and every night snow cloaks the mountains above. They're not too far from here.
I've written before about the need for tents but we don't just need tents, we need lots of gas cylinders too, so that people can cook and warm up themselves. What use are the tents without the warmth?
Mansehra, Sunday 16 October, 2020 local time (1520 GMT)
There is now snow on mountain tops that wasn't there yesterday.
Today we reached Kaladhaka, the tribal settlement we were trying to contact yesterday.
Snow is now clearly visible on mountains near Balakot
There must be 30 to 40 houses completely destroyed there and about 300 people dead. The survivors are desperate for shelter.
It's the same story everywhere we go.
The tribal leaders there were very calm and co-operative. There have been political problems there but they are irrelevant at a time like this.
I now have to go to the meeting that is held every evening between all the organisations that are working here, like the UN and Unicef.
We talk about what we have done, and what we plan to do tomorrow. This report is then sent to everyone so that we are co-ordinated.
There will be many more meetings ahead.
Mansehra, Saturday 15 October, 1930 local time (1430 GMT)
Last night, as we were sitting down discussing our day, there was suddenly a severe aftershock.
It was strong enough to knock me down, and there were worrying creaking noises from the walls.
The aftershocks are still coming strong. Not only that, but we awoke this morning to a sky full of clouds and heavy rain.
There are hundreds of thousands of people still without even plastic sheeting to make a shelter, not to mention a tent or even a stove to cook with.
Although the co-ordination of aid has improved with the UN arriving, distribution is still a massive problem.
Most of the food is carried by roads, which of course are still blocked. As well, I would say that about 70% of the population is scattered in settlements far away from the main roads.
These people have not been reached yet. They will have no aid, no shelter, nothing.
We spent part of the day in Baillian, where houses on mountain steps had fallen down upon one another.
There were about 10,000 people who were now at the base of the mountain, many begging for shelter.
But all we could do was offer them hope, that's all we can do.
At the moment we are trying to communicate with the tribal leaders in an area called Kaladhaka.
About 150,000 people live there, but we still don't know anything about their situation.
There is also another area we know about called Batagram - all we know is that the situation there is critical.
The evening was spent in Garihadidjul.
About 80% of the houses were damaged there and 600 children's bodies have been dragged out of the rubble of a school there.
There are so many more places we still need to reach.
Odhi, Friday 14 October, 1630 local time (1130 GMT)
All the medical buildings here have been damaged.
There are thousands of homeless people and an acute demand for shelter. Many of the houses are destroyed and Odhi is situated at a very high altitude, so the situation is critical. It's just freezing here.
We saw children outside without any shelter. We need at least 20,000 tents here alone.
They were in extreme psychological trauma. They were desperate because they have spent four or five days in the open.
Everyone is going to Balakot but that is a dead valley now. What about the rest? We know that there are still people in villages beyond, but everyone goes to this town of ghosts.
All the agencies are now co-ordinated and united - but that doesn't mean we have what we need. We are out in the field and we see with our own eyes that things are beyond the government and the army now.
We need international aid from all over the world.
There were two major aftershocks today. I saw the mountain and it looked as if it were about to split into two. An enormous rock was precariously suspended above us.
It could have killed us.
I've seen doctors in tears. They are on the frontline and they are working with people who are dying, people without shelter, sanitation, and they cannot cope with the trauma.
But I have also seen truck upon truck of aid from ordinary Pakistani people. My UN colleagues have told me they have never seen anything like this. It makes me feel proud.
It is the one positive thing amidst all this misery.
Balakot, Thursday 13 October, 1630 local time (1130 GMT)
There is not a single building standing in Balakot.
There is an extremely foul smell because the city is full of dead bodies.
We are focusing our efforts on surveys and logistics. The population of the city was about 24,000. It looks as if 70% of this population has been wiped out. Our data will help the government revise its figures.
The death toll will inevitably rise.
There are a few people still alive and a Chinese agency has set up a first aid camp. Another team from UAE has taken up the job of disposing of dead bodies.
There is talk of mobilising the population that is left and spraying the rest of the area, because of contamination fears.
Tomorrow I'm going to Odhi, a place nobody has yet reached.
There are airlift helicopters dropping food, tents and medication throughout the Mansehra district: the population is very scattered over there.
I have just felt a significant aftershock. Those people who are still in remote areas must be terrified.
Their first need is shelter. Temperatures are extremely low. People now have food and medicine, but shelter is what they desperately need.
The onset of the cold has changed all our priorities.
I can see that relief supplies are coming in, but tents please, more tents.
Mansehra, Wednesday 12 October, 1300 local time (0800 GMT)
There's a place called Jabouri, north of here. The road has been blocked by a landslide and beyond that there are many, many villages.
Let me give their names because most people won't have heard these names before: Manabocha, Jhacha, Pandur, Batangi.
People have come from these small mountain villages carrying the injured on their shoulders, walking for hours. We have heard horrific stories. The situation there is drastic.
Each village has about 250 houses, all of them are destroyed and in each home, people have died.
The government is not calculating fatalities properly. We have a survey team going to Balakot and they will establish numbers.
I have a feeling that in Balakot alone the death toll might be 15,000 or 20,000. But that is not official, these are just guesses - our team will collect data and supply it to the appropriate sources.
There are teams from all over the world and somebody has to co-ordinate them. We are going to lead them to the areas facing the direst need.
I have seen hundreds of patients here. There has been an outbreak of chest infections, respiratory tract problems here.
Supplies have only just reached here. Doctors are performing surgeries but without sterilisation equipment, surgical tools, without proper sanitation even.
Patients need to be taken to Peshawar. It has three huge hospitals waiting for patients - but they lie empty.
I'm very tired, but every hour is important.
I can see the distant mountains from here - they are covered in snow. Last night the temperature fell so low and I could only think of those people homeless outside, those villagers still trapped.
Mansehra, Tuesday 11 October, 1600 local time (1100 GMT)
I reached Mansehra with a UN team just a few minutes ago. The roads are crowded and it was a long, arduous journey from Abbottabad.
I am standing inside the main hospital. These newly-constructed buildings were totally damaged before anyone got a chance to use them.
The patients are outside under tents. I can see some being carried in by stretcher.
One thing is clear. Medical supplies have not reached Mansehra.
People are in a terrible condition but there is not much that doctors can do. We don't really have the right surgical equipment.
We have kidney specialists, we have some dialysis units but there is no electricity and no water so how can we install them?
There is no logistical organisation. We have no idea how many supplies are really needed, how many patients there are, how many there could be, even how many doctors are in the area.
We see Swiss and Chinese relief teams but even they are in chaos.
I have plans to head to even more remote northern areas.
I've spoken to a colleague who says that the town of Batagram has been levelled and there are serious casualties - an incredibly high death toll.
There are many dead bodies, but more importantly there are people still alive, still trapped.
One final plea is that we need helicopters urgently.
Peshawar, Monday 10 October, 1500 local time (1000 GMT)
When the earthquake struck, I was in the Ayub medical complex hospital at Abbottabad.
Much of the hospital was structurally damaged during the earthquake. Ceilings caved in, the emergency room had to be closed down.
Resting in hospital grounds in Abbottabad
After a few moments, huge panic set in. People started to pour into the hospital.
There were people dying, being separated from families - a huge mob filled with pain. There were aftershocks, and all people could do was lie down. The casualties were enormous.
In this city alone, buildings, plazas, shopping centres just fell down.
This is a city, what is it like in the villages?
And it took well over a day for any relief to start coming. They were busy in Islamabad not thinking of the thousands of people still trapped in these rural areas.
In the evening it rained and hailed as a huge storm arrived. It was unimaginable. People were out in the cold, terrified, grieving.
There is no shelter, lots of women and children are braving the extreme weather without food and water, becoming infected by pneumonia.
The psychological trauma is difficult to cope with. We try to reassure them but what can we do when these people have nothing?
They have only their injuries. Their houses have been demolished, they have no money, no place to go.
This is a rugged and remote region. Abbottabad is a city in a valley.
From Tuesday I will venture out into the mountainous areas, where I hope to make use of my skills.