Litomosoides sigmodontis

 

Contents

 

Rev 10/14/2025

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

Chromadorea
Chromadoria

 Rhabditida 

                               Spirurina
                                  Filarioidea
                           Filariidae or
  • Onchocercidae
  • Litomosoides sigmodontis Chandler, 1931

    Type species of the genus

    Synonyms:

    Litomosoides carinii Travassos, 1919

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    Morphology and Anatomy:

       

     

     

    Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:         

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    Distribution:

    A parasite of the pleural, pericardial and peritoneal cavities of the cotton rat, Sigmodon hispidus, and other rodents in North and South America,

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    Economic Importance:

    Litomosoides sigmodontis if mice has long been used as a model systems for research on filariasis (Hoffmann et al., 2001)

     

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    Feeding: 

     

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    Hosts:

    Definive hosts are rodents.

     
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    Life Cycle:


    The two In filarial nematodes, two hosts are required to complete the life cycle, an intermediate host (often an arthropd) and a primary or definitive host (usually a vertebrate). The juvenile stages occur in the intermediate host and the reproductive adult in the definitive (primary) ho
    st. Juvenile stages (microfilariae) are adapted to the anatomical and behavioral characteristics of intermediate and definitive hosts. So, morphometrics of microfilariae of different filarial species may be selected by the morphometrics of the organ and circulatory systems of particular hematophagus arthropod intermediate hosts, for exmaple mites, ticks or mosquitos.  For exemple, microfilariae of Litomosoides sigmodontis are in the range of 70-100 um in length and 4 um in diameter (Bain and Babayan, 2003).. 
    For a relative size-perspective, the infective second stage juveniles of the plant-parasitic nematode Meloidogyne incognita are 300-400 um long and 15 um in diameter.
    Of course, enormous increase in size can occur in the definivive hosts, rodents in the case of L. sigmodontis, adult females amd males may be, respectively, 33-120 and 14-28 mm in length, 0.3 and 0.15 mm in body diameter.

    Females  of Litomosoides sigmodontis in the thoracic cavity of the definitive host produce eggs that hatch to microfilariae which migrate through the lungs into the lymphatic and circulatory system. Microfilariae are ingested by mites, for example the tropical rat mite, Ornithonysuus bacoti, an intermediate host. The microfilariae develop into the L3 infective stage in about 15 days. They migrate to the mouthparts of the mite and enter the skin wound of the definitive hosts caused by mite feeding. They are carried through the heart and into the lungs by the circulatory system and molt to the 4th stage and adults in the thoracic cavity.
    The number of microfilaria in the blood of the definive host peaks in 4-56 months; adult worms may live for 3 years but most of them die after aboout 1 year

    Ecophysiological Parameters:

    For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters
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    Damage:

    Parasitic nematodes enhance their survival by affecting the immune systems of their hosts. Filaria of Litomosoides sigmodontis cause inflammatory responses of mice injected with sublethal doses of lipopolysaccharide (LPS). Female adult worms can mitigate the innate immune response.by causing the mice to develop lower levels of the proinflammatory cytokines in the peripheral blood Hubner et al (2008).

     

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    Management:

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    References:

    Bain, O., Babayan, S. 2003. Behaviour of filariae: morphological and anatomical signatures of their life style within the arthropod and vertebrate hosts. Filaria Journal 2, 16

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

    Durette-Desset, M-C. and Guerrero, R.A. 2006. A new species of Hypocristata (Nematoda, Trichstrongylina, Helimosomoidea) a parasite of Sigmodon hispidus (Cricetidae, Sigmodontinae) from Venezuela. Parasite 2006, 13

    Hoffmann, W.H., Pfaff, A.W., Schilx-Key, H., Soboslav, P.T. 2001. Determinants for resistance and susceptibility to microfilaraemia in Litomosoides sigmodontis filariasis. Parasitology 122: 641-649

    Hubner MP,Pasche B,.Kalaydjiev S, Soboslay PT,, Lengeling A,,  Schulz-Key H,,  Mitre E,, Hoffmann WH. 2008. Microfilariae of the Filarial Nematode Litomosoides sigmodontis Exacerbate the Course of Lipopolysaccharide-Induced Sepsis in Mice. Infection and Immunity, 76..

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    Copyright 1999 by Howard Ferris.
    Revised: October 14, 2025.