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Open Access Highly Accessed Research article

A novel bacterial symbiont in the nematode Spirocerca lupi

Yuval Gottlieb1*, Eran Lavy1, Meira Kaufman1, Alex Markovics2, Murad Ghanim3 and Itamar Aroch1

Author Affiliations

1 Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, P.O.B 12, Rehovot, 76100, Israel

2 Kimron Veterinary Institute, P.O.B 12, Bet-Dagan, 50250, Israel

3 Department of Entomology, Agricultural Research Organization, Volcani Center, P.O.B 6, Bet-Dagan, 50250, Israel

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BMC Microbiology 2012, 12:133  doi:10.1186/1471-2180-12-133

Published: 5 July 2012



The parasitic nematode Spirocerca lupi (Spirurida: Thelaziidae), the canine esophageal worm, is the causative agent of spirocercosis, a disease causing morbidity and mortality in dogs. Spirocerca lupi has a complex life cycle, involving an obligatory coleopteran intermediate host (vector), an optional paratenic host, and a definitive canid host. The diagnosis of spirocercosis is challenging, especially in the early disease stages, when adult worms and clinical signs are absent. Thus, alternative approaches are needed to promote early diagnosis. The interaction between nematodes and their bacterial symbionts has recently become a focus of novel treatment regimens for other helminthic diseases.


Using 16S rDNA-based molecular methods, here we found a novel bacterial symbiont in S. lupi that is closely related to Comamonas species (Brukholderiales: Comamonadaceae) of the beta-proteobacteria. Its DNA was detected in eggs, larvae and adult stages of S. lupi. Using fluorescent in situ hybridization technique, we localized Comamonas sp. to the gut epithelial cells of the nematode larvae. Specific PCR enabled the detection of this symbiont's DNA in blood obtained from dogs diagnosed with spirocercosis.


The discovery of a new Comamonas sp. in S. lupi increase the complexity of the interactions among the organisms involved in this system, and may open innovative approaches for diagnosis and control of spirocercosis in dogs.

Spirocercosis; Comamonas; Canine; Vector-borne helminthic diseases