A novel bacterial symbiont in the nematode Spirocerca lupi

Abstract

BackgroundThe 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.ResultsUsing 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.ConclusionsThe 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.

The bacterial community associated with the sheep gastrointestinal nematode parasite Haemonchus contortus

“…More recently, a Comomonas sp. has identified in eggs, the gut cells of L3 and adult Spirocerca lupi , a parasite principally of canids [ 80 ]. Although this symbiont was present in the strain of S .…”

Comparative Genomics of a Plant-Parasitic Nematode Endosymbiont Suggest a Role in Nutritional Symbiosis

“…Others include Cardinium strains in the plant-parasitic nematodes Globodera and Heterodera ( Noel and Atibalentja 2006 ), Comamonas sp. in parasitic spiruridean nematodes ( Gottlieb et al 2012 ), and an undescribed bacteria in the nematode Noctuidonema that are ectoparasites of insects ( Marti et al 1995 ). We speculate that within the X. americanum species-complex, members which depend most on phloem might depend more on this bacterial partner, whereas species within or outside of the X. americanum group that do not feed on phloem may not need this symbiont at all.…”

“…Bacteria-animal endosymbioses have arisen at least a dozen times from at least five bacterial phyla, often serving in biosynthesis of nutrients missing in the host diet ( Toft and Andersson 2010 ; Moran and Bennett 2014 ). These endosymbioses are common in the sap- and blood-feeding insects, but may occur more broadly among invertebrates that are pests of plants or parasites with specialized diets ( Gottlieb et al 2008 , 2012 ; Douglas 2009 ; Bright and Bulgheresi 2010 ). So far, it has been challenging to identify and characterize these associations due to difficulty culturing and manipulating the microbes; however, genomic tools now offer a promising approach for simultaneous discovery and functional analysis of vital microbial partners.…”

Frequency of canine nt230(del4) MDR1 mutation in prone pure breeds, their crosses and mongrels in Israel - insights from a worldwide comparative perspective.

“…In Israel, spirocercosis is a widespread disease and dogs are routinely treated with macrocyclic lactones parasiticide. On average, more than 20 dogs are diagnosed annually, with the highest infection rates in the center of the country [ 41 , 42 ]. The aim of this study was to determine the frequency of the mutant allele in Israel in the affected breeds, their crosses and undefined dogs, and to compare the data with recent worldwide studies.…”