Vectors and Transmission

What is a biological vector?

An agent develops and/or multiplies in the vector before onward transmission

What is a mechanical vector?

The agent is carried without required development or multiplication in the carrier, like a fly transferring infectious material on its body

What is an intermediate host?

A host supporting larval development and/or asexual reproduction

What is a definitive host?

A host where sexual maturity is reached and the lifecycle is complete

Life cycle of Nanophyetus salmincola

Direct hosts are canids, felids, humans, snail host inhabits fast moving streams. Fish harbor encysted Metacercariae stage

Important vectors and/or hosts

Dirofilaria immitus is transported via mosquitos, Fasciola hepatic is transmitted via snails onto grass, Paragonimus kellicotti has two intermediate hosts, Nanophyetus salmincola are transmitted via snails to fish to mammals

Nanophyetus salmincola

rarely causes disease in dogs, but can transmit Neoriskettsia helminthoeca

What is hyperparasatism? What is an example of it?

What is a common vector for agents in veterinary parasitology?

An arthropod

Can vectors overlap? What is an example?

Yes, a mosquito transmitting heartworm is both a biological vector and an intermediate host

Fasciola hepatica, Paragonimus kellicotti, Nanophyetus salmincola are all what?

Digenean trematodes

Dirofilaria immitis is what?

A filarid nematode

What is Neorikettsia helminthoeca?

A parasite transmitted by Nanophyetus salmincola, causes rickettsial disease when dogs eat raw salmon, causes fever, vomiting, diarrhea, ocular discharge, lympadenopathy and has a mortality rate between 50-90 percent

What other implications are there for the spread of Nanophyetus salmincola outside of dogs?

Humans can catch it and it can cause disease in fish, creating issues for fish farms and hatcheries