The rainy season does bring a few blessings to counter the continuing difficulty with transport: the ability to plant crops, the sudden transformation of a barren wasteland into a temporary green oasis, an influx of spectacularly colourful birds as well as a welcome respite from the searing heat - the midday heat has fallen from about 40C (104F) to the high 20s.

†It has been another action-packed week here in Garsila, Darfur. It began with a two-year-old child being brought into one of our Therapeutic Feeding Centres - where we and feed and monitor severely malnourished children. The mother had noticed the child was not walking as he had in the past and she wondered if this was due to lack of food.

Allyson Bowers, the American Médecin Sans Frontière (MSF) nurse who runs the feeding centre here, suspected something more serious to be awry. She asked Linda Garcia, a Salvadoran doctor from the outpatient clinic, to have a look. The obvious lack of movement of the child's left leg had raised the possibility of polio in Allyson's mind.

We have seen at least two other possible cases of this disease, which successful vaccination campaigns have virtually eradicated from the industrialised world. They remain suspected cases here as the remoteness of our location hinders confirmation.

We attempted to send a sample that must remain frozen by car to Nyala, a nine-to-10 hour drive across difficult roads. We hoped it would arrive in time to make one of the few flights each day from there to the capital of Sudan, Khartoum. The local authorities here were also notified and they began to trace and investigate the case, while we began a vaccination programme for all the infants in our feeding centre.

I have been occupied with journeys from our base here to smaller villages, many of which, we have heard, are isolated by insecurity. Any attempt to leave is met either by the demand for significant sums of money, beatings or, if the person is female, rape. Consequently, many of the villagers who are unwell will not travel to our clinics in neighbouring towns.

We travelled first to a village an hour's drive from Garsila; along with surrounding villages, it makes up a population of about 4,000 people. Upon arrival, we have a formal meeting with the chiefs ("ummda") and then run a brief clinic. We have to focus on the sickest people first, as we have a strict departure time. The security curfew is meant to ensure our own safety on these roads.

It is humbling to be treated with such enthusiasm and respect by the people in these small villages. They tell us of their ordeals in the preceding months and confirm many of the stories we have heard about the difficulty in travelling between towns.

A lunch is provided for us: the local staple diet called "aseeda", a grain-based dish with a consistency between porridge and pate and with a taste that suggests wallpaper glue. Given the scarcity of food, one cannot help but be amazed at the villagers' hospitality. They have only planted sorgum grain around their villages because - as they have learnt to their cost, earlier this year - raiding parties readily loot other crops, such potatoes, onions and tomatoes.

We have planned similar trips for the coming weeks to familiarise ourselves with the territory.

The MSF house in Garsila has been full in the past week, putting food and sleeping space at a premium, while the team normally based in the town of Mukjar has been staying for a few days. However, our new kittens have been getting extra pampering; we hope to have them rat-hunting as soon as possible. These other, unwelcome inhabitants of the house have also been increasing in number.

The rainy season does bring a few blessings to counter the continuing difficulty with transport: the ability to plant crops, the sudden transformation of a barren wasteland into a temporary green oasis, an influx of spectacularly colourful birds as well as a welcome respite from the searing heat - the midday heat has fallen from about 40C (104F) to the high 20s.

The electricity generator is gasping its last, so it is time to depart and finish my day curled up with a well-thumbed Dickens novel and a flashlight. Nights here do allow me to do a fair amount of reading - easily neglected at home with family and friends in New Zealand - another unforeseen advantage to aid work in Sudan with MSF!

Dr Dean Harris is an aid worker with MSF in Garsila, Darfur