Also known as: キャットシットワン
Cat Shit One is a three volume manga series written and illustrated by Kobayashi Motofumi. It was originally published in Japan in 1998 by Softbank Publishing.
The manga follows three American soldiers in the Vietnam War named Botasky, Packy and Rats. All three are in the recon team called Cat Shit One.
The depiction of Americans as rabbits is actually a pun on the Japanese word for rabbit. The Japanese word for rabbit is "うさぎ", which can be romanized as "usagi", or USA GI.