Moniliformis moniliformis is one of the two main acanthocephalans known to infect humans and cause acanthocephaliasis (the other being Macracanthorhynchus hirudinaceus). The definitive host for M. moniliformis (i.e., the host in which the parasite reaches maturity) is typically a rat, although carnivores and primates, including humans, may serve as accidental hosts. The parasite's eggs are ingested by an intermediate host (typically a beetle or cockroach), which is subsequently eaten by the definitive host, resulting in infection of the definitive host. In infected human hosts, the worms seldom mature or mature but do not produce eggs.
(Source: Centers for Disease Control Parasites and Health website)