Setaria

  

Contents

  

Rev 10/28/2025

  Classification Hosts
Morphology and Anatomy Life Cycle
Return to Setaria Menu Economic Importance Damage
Distribution Management
Return to Onchocercidae Menu Feeding  References
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Classification:

Chromadorea
 Chromadoria

           Rhabditida 

                       Spirurina
                          Filarioidea
                   Onchocercidae
 
  •             Setaria Viborg, 1795

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    Morphology and Anatomy:

    Nomenclatural note:  The name Setaria is also applied to an important genus of foxtail grasses.

    The genus Setaria included 43 species as of 2009 (Laaksonen et al., 2009). Nematodes of the peritonelal cavity of their hosts.

    General characteristics of the genus:

    Female:

    • Generally longer than males.
    • Viviparous, hatched microfilariae (larvae) released through muscular ovijector and vulval opening in cervical region.
    		  

    Male:

    • Spicules differ in length, left 3 x longer than right.
    • Shorter than females,.

    Ref: Buckland and Walker, 1969; Olos et al., 2021
    Body size range for the species of this genus in the database - Click:
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    Distribution:

    Common parasites of ungulates, icluding wild ruminants.

    Reported in Northern Europe, Hungary, Finland.

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    Economic Importance:

    Setaria tundra has significant veterinary health importance in boreal regions of Europe as the causative agent of setariosis in cervids (reindeer, roe deer, moose and others: Rangifer tarandus, Capreolus capreolus, Alces alces) (Laaksonen et al., 2007). In Finland, there have been severe outbreaks of S. tundra among semi-domestic reindeer (Laaksonen et al., 2009)

    Most Setaria species can cause neurological disorders, usually in accidental hosts (e.g. lumbar paralysis,  and cerebrospinal nematodosis) which can be lethal to the host. These symptoms can take place also in definitive hosts like buffalo.

    Setaria. equina and S. labiatopapillosa can cause intestinal  inflammation and pain. Setaria digitata and S. cervii can also cause ocular filariosis or even blindness (Olos et al., 2021)

    The significance of seteriosis in humans as accidental hosts is not yet well defined.

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    Feeding:

    Food Sources and Feeding strategies for the genus Setaria

     

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    Hosts:

    Causative agent of setariosis in reindeer, moose and other cervids  (Laaksonen et al., 2007). In Finland, there have been severe outbreaks of S. tundra among semi-domestic reindeer (Laaksonen et al., 2009)
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    Life Cycle:

    Transmitted by many species of mosquitoes.    

    Two hosts to complete the life cycle, an intermediate host (often an arthropd) and a primary host (usually a vertebrate). The juvenile stages occur in the intermediate host and the reproductive adult in the definitive (primary) host.

    Microfilariae are taken up during feeding on an infected host by many species of mosquitoes. The L3 develops in the mosquito in about 12 days and infect suitable definitive hosts. The prepatent period when detectable forms are present in the host blood is 8-10 months (Dzmianski et al., 2020).

    For Ecophysiological Parameters for this genus, click 
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    Damage:

    Setaria species infect the peritoneal cavity surface and are free in the lumen of the pleural cavities of ruminants, equids, and swine worldwide.  They are usually considered harmless but they can cause serious damage to neurological tissues (Dzimianski et al., 2020).

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    Management:

    Ivermectin is prescribed as an anthelminthic. Preventative use of the drug require that it be administered throughout the period of mosquito activity,

    Molecular detection methods are expanding the knowledge-base of the importance of many species of  mosquitoes as vectors of filerial nematodes (Kemenesi et al., 2015).

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    References:

    Bucklund, W.W. and Walker, M.L. 1969. Taxonomy, hosts and geographic distribution of the Setaria (NematodaL Filarioidea) in the United States and Canada. J. Parasitol. 55:359-368.

    Dzimianski, M.T., Marchiondo, A.A., Cruthers, L.R. 2020. Nematoda, Filarioidea. Chapter 2 in Marchiondo, Cruthers and Fourie (eds) Parasiticide Screening Vol 2. Academic Press.

    Kemenesi, G., Kurucz, K., Kepner, A., Dallos, B., Oldal, M., Herczeg, R., Vajdovicz, P., Binjai, K., Jakab, F. 2015. Circulation of Dirofilaria repens, Setaria tundra, and Onchocercidae species in Hungary during the period 2011-2013. Veterinary Parasitology 214: 104-113.

    Laaksonen, S., Kuusela, J., Nikander, S., Nylund, M., Oksanen, A., 2007. Outbreak of parasitic peritonitis in reindeer in Finland. Vet. Rec. 160: 835-841.

    Laaksonen, S., Solismaa, M., Kortet, R., Kuusela, J., Oksanen, A., 2009. Vectors and transmission dynamics for Setaria tundra (Filarioidea; Onchocercidae), a parasite of reindeer in Finland. Parasit. Vectors 2: 3.

    Olos, G., Nowakowska, J., Welc-Faleciak, 2021. Setaria tundra, what do we know, what is still to be discovered?. Annals of Parasitology 67:1-10.

    Sundar, S.T.B., D'Souza, P.E. 2015. Morphological characterization of Setaria worms collected from cattle. J. Parasit. Dis. 39:572-576.

     

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    Copyright 1999 by Howard Ferris.
    Revised: October 28, 2025.