Nippostrongylus brasiliensis is gastrointestinal nematode parasite of rodents.
Adults produce eggs in the intestine, which then pass out of the host in faeces. The larvae then develop into their infective L3 stage.
This stage then penetrates the hosts skin or is ingested. They are then carried by circulation to the heart and lungs where they penetrate aveoli. Here they are coughed up and swallowed and then enter the intestine, attached to the intestinal wall where they develop into adults, producing eggs so that the cycle continues.