If you want to get from Phnom Penh to Silk Island, all you need to do is stop one of the thousands of "Tuk Tuk" motorbike taxis that circle the streets of the noisy Cambodian capital, travelling in endless loops. 

Although the drive to the island only takes about an hour, it is still adventurous: after we had left the traffic of the main roads behind us, the road suddenly ends in a grassy pedestrian path. While the majestic Mekong River flows by beside the path, as it has done for thousands of years, my driver gets out of his vehicle with south-east Asian composure. Unconcernedly he inspects the few centimetres wide path for a while and finally decides that this is the end of the trail. After a lot of back and forth, we finally find the ferry that takes us across the river to Silk Island - just a short ten minute journey.

Early in the morning we set off for a Buddhist temple, where we would be holding our mobile clinic. The aim is to vaccinate, medicate and sterilise five hundred dogs and cats within a few days. How necessary the latter in particular is, only became clear to our team after arriving on the island: every household seems to have taken in several animals here, yet the population is still growing unhindered.

Early in the morning the first residents are already waiting for us to bring their animals. Our help is taken up with open arms as there is no veterinarian on the island. The crossing to Phnom Penh is not affordable for most people - let alone expensive veterinary care for their beloved dogs and cats.

Our team works on a piecework basis, our animal patients are cared for from morning to night. Even the local monks help us to collect them, and for the particularly shy contemporaries we have specially flown in our stray dog team from the Ukraine, who successfully catch even the shyest dogs and cats.

In addition, along with a colleague from Animal Rescue Cambodia, we drove from house to house to pick up animals directly from the rustic homes of the residents. I meet a lady who had thirteen dogs with her, everyday she has to prepare food for the hungry mouths, which is a challenge on this island where everyone has just enough for themselves. But she does it with joy because she does not want anything to happen to the animals - the henchmen of the dog meat trade are unfortunately very present in Cambodia.

As we drive back to the clinic, we can see commotion as an emergency case has just been rushed into the clinic. Dog Ginou is having a lot of trouble breathing, and you can see the reason at first sight: his belly is very bloated and apparently filled with fluid. Dr Katherine Polak, veterinarian and head of our Stray Animal Care in South East Asia, explains to me that the fluid is pressing on his chest and heart, making it difficult for him to breathe. She decides that he must be taken off the island and to a veterinary clinic immediately to save his life.

It is now late afternoon, and in our clinic, under the open sky, it is 36 degrees - in the shade! Not even a gentle breeze moves the air, which shimmers with heat. Nevertheless, I hardly notice any signs of fatigue within the team, despite working the whole day through except for a short lunch break. Dr Polak helps out wherever she can, undeterred by a knee injury on her first day at work. In the hospital in Phnom Penh, she was fitted with a temporary splint, but instead of curing her injury, she returned to her team the very next day.

With so much going on, the days on Silk Island pass quickly, and the number of animals to be treated seems to be endless. On the last day of the mission, Dr Polak takes me to Phnom Penh. Together we want to visit dog Ginou, who has been treated in a clinic in the city for the last few days. Luckily the therapy has taken full effect and Ginou greets us already tail-wagging and full of energy. The next day he is to be brought back to the island to his eagerly waiting owner.

On the last evening, I ask Dr Polak whether she is already looking forward to the weekend after the sweaty days on the island. She tells me that she would leave early in the morning the next day to visit a dog slaughterhouse in the Cambodian hinterland. She wants to talk to the owner and try to convince him of the cruelty of the dog meat industry and together with him find another way to feed his family. The fight for animal welfare does not stop. 

There is still a long way to go for us here in Cambodia and in Southeast Asia, but at least on Silk Island, there are now several hundred dogs and cats that can watch the Mekong River flow, healthy and happy.