A five-year-old boy with autism who couldn’t stand being hugged or touched has been photographed resting his head against his new service dog.

In a post to the Love What Matters Facebook page , US mother Shanna Niehaus describes her son’s first meeting with service dog “Tornado” after nearly two years of waiting.

The photo is accompanied by a photo of a boy leaning against the side of the dog, using an iPad, while Ms Niehaus sits behind him weeping.

"See this moment? I've never experienced a moment like this,” she wrote.

“This picture captures the face of a mother who saw her child, who she can't hug, wash, dress, snuggle and touch freely, lay on his new service dog of his own free will, with a purposeful, unspoken attachment.”

Ms Niehaus said despite her son’s best efforts, he has struggled to socialise and form connections with others, leading to “countless challenging and painful moments”.

She also said while these moments have previously moved her to tears, the sight of her son bonding with the service dog left her with an “indescribable” feeling.

“Somehow because of this - because of Tornado - I know everything will be okay,” Ms Niehaus wrote.

The post has since received hundreds of thousands of reactions and more than 125,000 shares.

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