Microfilaria

Part of speech: noun

Definitions

1. The immature larval form of a thread-like parasitic worm that circulates in the bloodstream of an infected host
2. A tiny worm larva found in the blood of people or animals infected by certain filarial nematodes
3. The early larval stage of a filarial roundworm, typically found moving through blood or lymph of its host

Etymology: The word is a straightforward compound, built from "micro-" and "filaria." The first part comes from Ancient Greek "mīkrós," meaning "small," which entered English as the prefix "micro-" and now appears in countless scientific terms. The second part, "filaria," is the name of a genus of threadlike worms, taken from Latin "filum," meaning "thread," so the whole term describes a small thread-like worm. In practice, a microfilaria is the early developmental stage of a filarial nematode, a parasitic worm that lives in the lymphatic system or other tissues of its host and is spread by biting insects. These larvae circulate in the blood of an infected person, which is why clinicians can detect them by examining a blood sample. The term is a modern scientific coinage, formed from classical roots rather than something ancient writers would have used.