NewsDesk @bactiman63

The New Hampshire Department of Health and Human Services (DHHS) reported in a health alert last week that there have been two human cases of Echinococcus (tapeworm) infection acquired in northern New Hampshire.


On April 11, 2022, health officials were notified of a confirmed case of human pulmonary Echinococcus granulosus (EG) causing cystic echinococcus (CE). On December 1, 2022, a second case of CE in an unrelated patient was confirmed. Both patients likely acquired infection in northern New Hampshire and reported the epidemiologic risk of dressing locally hunted moose and exposure to dogs, which can serve as a definitive host.

These are the first identified cases of locally-acquired Echinococcus in the state of New Hampshire.

In the United States, EG is a rare parasitic infection that has historically been identified in the Western and Midwestern states; however, EG has recently emerged in wildlife in the Northeast.

EG is a zoonotic parasite. Adult tapeworms live in the intestine of canids (e.g., dogs, coyotes, and foxes). Canid feces contain parasitic eggs that are infectious to humans and other intermediate animal hosts (e.g., ungulates such as moose, deer, and sheep). In the intermediate host, the eggs hatch in the small intestine to form oncospheres which penetrate the intestinal mucosa and enter the circulation and then infect organs, especially the liver and lungs, where cysts form. Canids can become infected when they ingest raw flesh and viscera of an infected intermediate host.

Humans become infected when they ingest eggs that are shed in canid feces, usually through ingestion of raw produce contaminated by canid feces or through direct contact with infected feces. Ingesting meat infected with Echinococcus cysts does not cause disease in humans.

Patients usually present when cysts are identified in a vital organ either incidentally or because the cysts are causing symptoms such as through mass effect. The incubation period is currently unknown, but may be years. Complications (such as anaphylactic reaction) can happen if the cyst ruptures either spontaneously or during surgical manipulation. Cyst rupture can also cause secondary seeding of daugther cysts in the infected person.