This is a short story that Patrick published in the December 1971 issue of Fantasy & Science Fiction.
Quoting the teaser: “Patrick Meadows (“A Rag, A Bone,” August 1971) returns with a refreshing story about a County Health worker whose search for a mysterious animal that has bitten a young boy turns into an unforgettable experience.”
You can click on each image to see a larger version which should make it easier to read.
Cover (Dec 1971 F&SF) 
Page 118 (Dec 1971 F&SF) 
Page 119 (Dec 1971 F&SF) 
Page 120 (Dec 1971 F&SF) 
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Patrick Meadows 1934 – 2017.