Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses

Steven A. Nadler, Ramon A. Carreno, Byron J. Adams, Hailu Kinde, James G. Baldwin, Manuel Mundo-Ocampo

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Phylogenetic relationships among six isolates of Halicephalobus gingivalis (Stefanski, 1954), a species with pathogenic potential in horses and humans, were evaluated using DNA sequences from the nuclear large-subunit ribosomal RNA (LSU rDNA) gene. Sequences from nematodes obtained from in vitro cultures (soil or clinical sources), or isolated from infected horse tissues, were compared. Gene sequences from a fatal equine clinical case from southern California and a free-living isolate recovered from southern California soil showed no fixed differences. Sequences from isolates representing two fatal equine cases from North America, one from Ontario, Canada and another from Tennessee also showed no fixed differences. In contrast, two equine cases from Tennessee had 18 fixed differences for this LSU region, the greatest observed among isolates from horses. Phylogenetic analysis of six Halicephalobus sequences and four outgroup taxa by maximum parsimony yielded one tree with five well-supported clades. This phylogeny did not group isolates of Halicephalobus strictly by region of geographic isolation or source of sample, and depicted one clinical and one soil isolate as sister taxa. These results confirm that free-living environmental isolates are potential sources of infection for horses. The phylogeny also reveals that diverse isolates can cause infections in horses within a relatively limited geographic region, and conversely that genetically similar sister taxa can be recovered from geographically distant localities. PCR primers that selectively amplify Halicephalobus DNA were designed and tested based on comparison of closely related nematodes as inferred from phylogenetic analysis.

Original languageEnglish (US)
Pages (from-to)1115-1125
Number of pages11
JournalInternational Journal for Parasitology
Volume33
Issue number10
DOIs
StatePublished - Sep 2003

Fingerprint

Nematoda
Horses
Soil
Phylogeny
Large Ribosome Subunits
Ontario
North America
Ribosomal DNA
Infection
Genes
Canada
Polymerase Chain Reaction
DNA

Keywords

  • Halicephalobus gingivalis
  • Molecular systematics
  • PCR diagnostics
  • Ribosomal DNA

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

Cite this

Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda : Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses. / Nadler, Steven A.; Carreno, Ramon A.; Adams, Byron J.; Kinde, Hailu; Baldwin, James G.; Mundo-Ocampo, Manuel.

In: International Journal for Parasitology, Vol. 33, No. 10, 09.2003, p. 1115-1125.

Research output: Contribution to journalArticle

@article{e06bf0d7304f4026a80950e326de0e94,
title = "Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses",
abstract = "Phylogenetic relationships among six isolates of Halicephalobus gingivalis (Stefanski, 1954), a species with pathogenic potential in horses and humans, were evaluated using DNA sequences from the nuclear large-subunit ribosomal RNA (LSU rDNA) gene. Sequences from nematodes obtained from in vitro cultures (soil or clinical sources), or isolated from infected horse tissues, were compared. Gene sequences from a fatal equine clinical case from southern California and a free-living isolate recovered from southern California soil showed no fixed differences. Sequences from isolates representing two fatal equine cases from North America, one from Ontario, Canada and another from Tennessee also showed no fixed differences. In contrast, two equine cases from Tennessee had 18 fixed differences for this LSU region, the greatest observed among isolates from horses. Phylogenetic analysis of six Halicephalobus sequences and four outgroup taxa by maximum parsimony yielded one tree with five well-supported clades. This phylogeny did not group isolates of Halicephalobus strictly by region of geographic isolation or source of sample, and depicted one clinical and one soil isolate as sister taxa. These results confirm that free-living environmental isolates are potential sources of infection for horses. The phylogeny also reveals that diverse isolates can cause infections in horses within a relatively limited geographic region, and conversely that genetically similar sister taxa can be recovered from geographically distant localities. PCR primers that selectively amplify Halicephalobus DNA were designed and tested based on comparison of closely related nematodes as inferred from phylogenetic analysis.",
keywords = "Halicephalobus gingivalis, Molecular systematics, PCR diagnostics, Ribosomal DNA",
author = "Nadler, {Steven A.} and Carreno, {Ramon A.} and Adams, {Byron J.} and Hailu Kinde and Baldwin, {James G.} and Manuel Mundo-Ocampo",
year = "2003",
month = "9",
doi = "10.1016/S0020-7519(03)00134-6",
language = "English (US)",
volume = "33",
pages = "1115--1125",
journal = "International Journal for Parasitology",
issn = "0020-7519",
publisher = "Elsevier Limited",
number = "10",

}

TY - JOUR

T1 - Molecular phylogenetics and diagnosis of soil and clinical isolates of Halicephalobus gingivalis (Nematoda

T2 - Cephalobina: Panagrolaimoidea), an opportunistic pathogen of horses

AU - Nadler, Steven A.

AU - Carreno, Ramon A.

AU - Adams, Byron J.

AU - Kinde, Hailu

AU - Baldwin, James G.

AU - Mundo-Ocampo, Manuel

PY - 2003/9

Y1 - 2003/9

N2 - Phylogenetic relationships among six isolates of Halicephalobus gingivalis (Stefanski, 1954), a species with pathogenic potential in horses and humans, were evaluated using DNA sequences from the nuclear large-subunit ribosomal RNA (LSU rDNA) gene. Sequences from nematodes obtained from in vitro cultures (soil or clinical sources), or isolated from infected horse tissues, were compared. Gene sequences from a fatal equine clinical case from southern California and a free-living isolate recovered from southern California soil showed no fixed differences. Sequences from isolates representing two fatal equine cases from North America, one from Ontario, Canada and another from Tennessee also showed no fixed differences. In contrast, two equine cases from Tennessee had 18 fixed differences for this LSU region, the greatest observed among isolates from horses. Phylogenetic analysis of six Halicephalobus sequences and four outgroup taxa by maximum parsimony yielded one tree with five well-supported clades. This phylogeny did not group isolates of Halicephalobus strictly by region of geographic isolation or source of sample, and depicted one clinical and one soil isolate as sister taxa. These results confirm that free-living environmental isolates are potential sources of infection for horses. The phylogeny also reveals that diverse isolates can cause infections in horses within a relatively limited geographic region, and conversely that genetically similar sister taxa can be recovered from geographically distant localities. PCR primers that selectively amplify Halicephalobus DNA were designed and tested based on comparison of closely related nematodes as inferred from phylogenetic analysis.

AB - Phylogenetic relationships among six isolates of Halicephalobus gingivalis (Stefanski, 1954), a species with pathogenic potential in horses and humans, were evaluated using DNA sequences from the nuclear large-subunit ribosomal RNA (LSU rDNA) gene. Sequences from nematodes obtained from in vitro cultures (soil or clinical sources), or isolated from infected horse tissues, were compared. Gene sequences from a fatal equine clinical case from southern California and a free-living isolate recovered from southern California soil showed no fixed differences. Sequences from isolates representing two fatal equine cases from North America, one from Ontario, Canada and another from Tennessee also showed no fixed differences. In contrast, two equine cases from Tennessee had 18 fixed differences for this LSU region, the greatest observed among isolates from horses. Phylogenetic analysis of six Halicephalobus sequences and four outgroup taxa by maximum parsimony yielded one tree with five well-supported clades. This phylogeny did not group isolates of Halicephalobus strictly by region of geographic isolation or source of sample, and depicted one clinical and one soil isolate as sister taxa. These results confirm that free-living environmental isolates are potential sources of infection for horses. The phylogeny also reveals that diverse isolates can cause infections in horses within a relatively limited geographic region, and conversely that genetically similar sister taxa can be recovered from geographically distant localities. PCR primers that selectively amplify Halicephalobus DNA were designed and tested based on comparison of closely related nematodes as inferred from phylogenetic analysis.

KW - Halicephalobus gingivalis

KW - Molecular systematics

KW - PCR diagnostics

KW - Ribosomal DNA

UR - http://www.scopus.com/inward/record.url?scp=0142092592&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0142092592&partnerID=8YFLogxK

U2 - 10.1016/S0020-7519(03)00134-6

DO - 10.1016/S0020-7519(03)00134-6

M3 - Article

C2 - 13129534

AN - SCOPUS:0142092592

VL - 33

SP - 1115

EP - 1125

JO - International Journal for Parasitology

JF - International Journal for Parasitology

SN - 0020-7519

IS - 10

ER -