RESUMEN
Strongylus vulgaris has high pathogenicity to equines. It causes aneurysm and thrombosis in the arteries particularly an anterior mesenteric artery, that is fatal to equines. In this study, we aimed to diagnose microscopically the natural infection of donkeys with Strongylus vulgaris from Sadat City, Minoufiya Governorate, Egypt. Fecal egg culture was used after the diagnosis of strongyle eggs to identify the species. Hematological and biochemical parameters were assessed. Adult worms were collected after post mortem examination of the infected animal. The sequence of ITS-2 was used to confirm the species of the parasite. The infection rate was 15.85% using the microscopical examination. The larval culture confirmed the infection with strongyle eggs as Strongylus vulgaris larvae. The sequence of ITS-2 was highly identical (about 95%) to sequences from Germany, China, and Turkey and occurred in the same genetic clade with the sequence from Germany. In conclusion, the study presented the diagnosis, the changes in the hematological and biochemical parameters in the infected animals, and the genetic characterization of Strongylus vulgaris from Sadat City, Minoufiya Governorate Egypt for the first time.
Asunto(s)
Equidae/parasitología , Infecciones Equinas por Strongyloidea , Strongylus/clasificación , Animales , Egipto/epidemiología , Heces/parasitología , Caballos , Larva , Recuento de Huevos de Parásitos/veterinaria , Infecciones Equinas por Strongyloidea/epidemiología , Strongylus/aislamiento & purificaciónRESUMEN
REASONS FOR PERFORMING STUDY: Strongylus vulgaris is a pathogenic helminth parasite infecting horses and was once considered to be the primary cause of colic. Migrating larvae cause ischaemia and infarction of intestinal segments. This knowledge is derived from case reports and experimental inoculations of parasite-naïve foals, and it remains unknown to what extent the parasite is associated with different types of colic. OBJECTIVES: To evaluate the role of S. vulgaris as a risk factor for different types of colic in horses. STUDY DESIGN: A retrospective case-control study among horses referred with abdominal pain to the University of Copenhagen Large Animal Teaching Hospital during 2009-2011. METHODS: Each colic case was matched with an equid of the same type (pony, Warmblooded or Coldblooded), age, sex and admitted in the same month and year but for problems unrelated to the gastrointestinal tract. Serum samples were analysed for antibodies to migrating S. vulgaris larvae using a recently developed enzyme-linked immunosorbent assay (ELISA). The following 4 case definitions were used: colic sensu lato, i.e. all horses presenting with colic (n = 274), with further subgroups, i.e. undiagnosed colics (n = 48), strangulating obstructions (n = 76) and nonstrangulating infarctions (n = 20). RESULTS: Strongylus vulgaris antibody levels were similar to control values in colics sensu lato and horses with undiagnosed colic. In contrast, nonstrangulating intestinal infarctions were significantly associated with positive S. vulgarisâ ELISAs (odds ratio 5.33, 95% confidence interval 1.03-27.76, P = 0.05). Also, horses with nonstrangulating infarctions had a significantly higher occurrence of positive ELISAs than horses with strangulating obstructions (odds ratio 3.79, 95% confidence interval 1.34-10.68, P = 0.01) and the colic sensu lato group (odds ratio 3.09, 95% confidence interval 1.20-8.01, P = 0.02). CONCLUSIONS: Nonstrangulating intestinal infarction was strongly associated with S. vulgaris-specific antibodies, whereas the more broadly defined colic categories were not associated with positive ELISA results. Thus, the ELISA holds potential to become a helpful adjunct in diagnosis and management of horses with colic.
Asunto(s)
Enfermedades de los Caballos/parasitología , Infarto/veterinaria , Parasitosis Intestinales/veterinaria , Infecciones por Strongylida/veterinaria , Strongylus/clasificación , Animales , Cólico/etiología , Cólico/patología , Cólico/veterinaria , Dinamarca/epidemiología , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/patología , Caballos , Infarto/epidemiología , Infarto/parasitología , Infarto/patología , Parasitosis Intestinales/epidemiología , Parasitosis Intestinales/patología , Infecciones por Strongylida/complicaciones , Infecciones por Strongylida/epidemiología , Infecciones por Strongylida/parasitologíaRESUMEN
The roundworms of genus Strongylus are the common parasitic nematodes in the large intestine of equine, causing significant economic losses to the livestock industries. In spite of its importance, the genetic data and epidemiology of this parasite are not entirely understood. In the present study, the complete S. equinus mitochondrial (mt) genome was determined. The length of S. equinus mt genome DNA sequence is 14,545 bp, containing 36 genes, of which 12 code for protein, 22 for transfer RNA, and two for ribosomal RNA, but lacks atp8 gene. All 36 genes are encoded in the same direction which is consistent with all other Chromadorea nematode mtDNAs published to date. Phylogenetic analysis based on concatenated amino acid sequence data of all 12 protein-coding genes showed that there were two large branches in the Strongyloidea nematodes, and S. equinus is genetically closer to S. vulgaris than to Cylicocyclus insignis in Strongylidae. This new mt genome provides a source of genetic markers for the molecular phylogeny and population genetics of equine strongyles.
Asunto(s)
ADN de Helmintos/química , ADN Mitocondrial/química , Genoma Mitocondrial/genética , Filogenia , Strongylus/genética , Secuencia de Aminoácidos , Animales , Complejo IV de Transporte de Electrones/genética , Equidae/parasitología , Caballos , Intestino Grueso/parasitología , ARN de Transferencia/genética , Infecciones Equinas por Strongyloidea/parasitología , Strongylus/clasificaciónRESUMEN
Postmortem parasitic examinations of the large intestines of 725 slaughtered horses from individual farmers in southeastern Poland were carried out. The examinations were carried out monthly since February 2006 until January 2007 (except for August 2007 because of a technological stoppage in the slaughterhouse). The examinations included the intensiveness and extensiveness of the infestation of the Strongylidae belonging to the Strongylus genus. The Strongylidae were found in 26.5% of the examined horses. Strongylus vulgaris was the most dominant nematode and had a 22.8% prevalence, Strongylus edentatus was carried by 18.3% of the horses. Strongylus equinus was identified only in 1.7% of the examined horses. Our findings revealed that combined infestation of S. vulgaris and S. edentatus occurred in 100 (52.1%) of the 725 horses infected by the Strongylidae. The present results indicate that the lowest prevalence of strongyle species except for S. equinus was found in January, February, and March. However, it is difficult to draw a conclusion because of an extremely low extensiveness of infestation. The results indicate that the prevalence of the Strongylidae in horses from southeastern Poland is limited.
Asunto(s)
Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/parasitología , Caballos/parasitología , Infecciones por Strongylida/veterinaria , Strongylus/clasificación , Strongylus/aislamiento & purificación , Animales , Autopsia , Enfermedades de los Caballos/patología , Intestino Grueso/parasitología , Intestino Grueso/patología , Polonia/epidemiología , Prevalencia , Infecciones por Strongylida/epidemiología , Infecciones por Strongylida/parasitología , Infecciones por Strongylida/patologíaRESUMEN
Strongyle parasites are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic helminth parasite of horses. Recent investigations have suggested an association between occurrence of this parasite and usage of selective therapy based on regular fecal egg counts. The established diagnostic method for S. vulgaris involves larval culture and subsequent morphological identification of third stage larvae under the microscope. Recently, a real-time PCR assay was developed and validated for the detection and semi-quantification of S. vulgaris eggs in equine fecal samples. The purposes of the present study were (a) to determine the presence of S. vulgaris by real-time PCR in Danish and American horses on farms using vastly different anthelmintic treatment regimens and (b) to evaluate the association between larval culture results and the PCR. A total of 991 horses representing 53 different horse farms in Denmark and Central Kentucky were studied. Fresh fecal samples were collected from all horses, and strongyle eggs retrieved for DNA extraction and subsequent real-time PCR analysis. Individual larval cultures were performed on the Danish part of the data set (663 horses on 42 farms). On the Danish farms, the S. vulgaris PCR prevalence was found to be 9.2% on farms not basing parasite control on fecal egg counts, and 14.1% on farms using selective therapy. No horses were PCR positive in the American part of the study (328 horses on 11 farms). Kappa-values indicated a moderate agreement between PCR and larval culture results, while McNemar tests revealed no statistical difference between the paired proportions. Significant associations were found between PCR cycle of threshold (Ct) value groups and larval culture counts. Results indicate that both diagnostic methods can be useful for determining the occurrence of S. vulgaris on horse farms, but that they both are affected by potential sources of error. The PCR results confirmed previous findings suggesting that S. vulgaris can reemerge under selective therapy regimens.
Asunto(s)
Enfermedades de los Caballos/parasitología , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Infecciones por Strongylida/veterinaria , Strongylus/clasificación , Animales , Antihelmínticos/uso terapéutico , Dinamarca/epidemiología , Enfermedades de los Caballos/tratamiento farmacológico , Enfermedades de los Caballos/epidemiología , Caballos , Kentucky/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Infecciones por Strongylida/tratamiento farmacológico , Infecciones por Strongylida/epidemiologíaRESUMEN
African savannah elephants (Loxodonta africana) are an ecologically and economically important species in many African habitats. However, despite the importance of elephants, research on their parasites is limited, especially in wild populations. Currently, we lack genetic tools to identify elephant parasites. We present genetic markers from ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA) to identify five elephant-specific nematode parasites in the family Strongylidae: Murshidia linstowi, Murshidia longicaudata, Murshidia africana, Quilonia africana, and Khalilia sameera. We collected adult nematodes from feces deposited by wild elephants living in Amboseli National Park, Kenya. Using both morphologic and genetic techniques, we found that the internal transcribed spacer (ITS) region in rDNA provides a reliable marker to distinguish these species of strongyles. We found no evidence for cryptic genetic species within these morphologic species according to the cox-1 region of mtDNA. Levels of genetic diversity in strongyles from elephants were consistent with the genetic diversity seen within other strongyle species. We anticipate that these results will be a useful tool for identifying gastrointestinal nematode parasites in elephants.
Asunto(s)
Elefantes/parasitología , Variación Genética , Infecciones por Strongylida/veterinaria , Strongylus/genética , Animales , Animales Salvajes/parasitología , ADN Mitocondrial/análisis , Heces/parasitología , Marcadores Genéticos , Kenia , Infecciones por Strongylida/parasitología , Strongylus/clasificaciónRESUMEN
Cathespin L-like proteases (CPLs), characterized from a wide range of helminths, are significant in helminth biology. For example, in Caenorhabditis elegans CPL is essential for embryogenesis. Here, we report a cathepsin L-like gene from three species of strongyles that parasitize the horse, and describe the isolation of a cpl gene (Sv-cpl-1) from Strongylus vulgaris, the first such from equine strongyles. It encodes a protein of 354 amino acids with high similarity to other parasitic Strongylida (90-91%), and C.elegans CPL-1 (87%), a member of the same Clade. As S.vulgaris cpl-1 rescued the embryonic lethal phenotype of the C.elegans cpl-1 mutant, these genes may be orthologues, sharing the same function in each species. Targeting Sv-CPL-1 might enable novel control strategies by decreasing parasite development and transmission.
Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/enzimología , Caenorhabditis elegans/genética , Catepsinas/genética , Strongylus/enzimología , Strongylus/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Proteínas de Caenorhabditis elegans/química , Catepsina L , Catepsinas/química , ADN Complementario/química , ADN de Helmintos/química , Caballos , Datos de Secuencia Molecular , Mutación , Filogenia , ARN de Helminto/genética , ARN de Helminto/aislamiento & purificación , Alineación de Secuencia , Strongylus/clasificaciónRESUMEN
BACKGROUND: The objective of this study was to evaluate the strongyles species in 34 Pure Blood Arabian Horses: one-year-old mares (n = 12) and two-year old mares (n = 22) from the horse stud in 2005, kept under housed-pastured system and dewormed systematically, twice a year using the ivermectin compounds. MATERIAL AND METHODS: The practical method of in vivo determination of strongyles species in horses is collection of these nematodes from the feaces after treatment. Nematodes were collected 24 hours after deworming from 1000 g sample of feaces, then were classified to appropriate species and relative abundance of strongyles community was determined. RESULTS: In the feaces of horses after treatment 10 species of cyathostomes was determined: Cyathostomum catinatum (CAT), C. pateratum (PAT), Cylicocyclus nassatus (NAS), C. ashworti (ASH), C. leptostomus (LEP), C. insigne (INS), Cylicostephanus longibursatus (LNG), C. goldi (GLD), C. calicatus (CAL) and Coronocyclus coronatus (COR). No large strongyles (Strongylinae) was found. The relative abundance was the highest for following cyathostomes species: NAS (22%), CAT (18.1%), INS (17.7%), PAT (13.8%), LNG (9.1%) and LEP (8.2%). The relative abundance of cyathostomes species was similar in both group of mares. On the other hand CAL (15.8%) was common for the one-year-old mares and INS (25%) for the two-year-old mares. In vivo diagnositic of the infection is important from the perspective of individual small strongyle infections dynamics in horses and because of possible different pathogenicity of individual species of these nematodes.
Asunto(s)
Caballos/parasitología , Infecciones Equinas por Strongyloidea/diagnóstico , Infecciones Equinas por Strongyloidea/parasitología , Animales , Heces/parasitología , Femenino , Polonia/epidemiología , Especificidad de la Especie , Infecciones Equinas por Strongyloidea/epidemiología , Strongylus/clasificación , Strongylus/aislamiento & purificaciónRESUMEN
This study evaluated the gastrointestinal helminth fauna of long-nosed armadillos, Dasypus novemcinctus, from the Pantanal wetlands, Aquidauana sub-region, Aquidauana County, Mato Grosso do Sul State, Brazil. Thirteen species of nematodes, comprising seven genera and four families, were recovered from their gastrointestinal tracts. The following descriptors of infection were determined: prevalence, variation of intensity, average intensity and abundance. Hadrostrongylus speciosum n. gen. et n. sp. is first described here.
Asunto(s)
Armadillos/parasitología , Filogenia , Infecciones por Strongylida/veterinaria , Strongylus/clasificación , Strongylus/aislamiento & purificación , Animales , Brasil/epidemiología , Femenino , Masculino , Recuento de Huevos de Parásitos/veterinaria , Densidad de Población , Dinámica Poblacional , Prevalencia , Especificidad de la Especie , Infecciones por Strongylida/epidemiología , Infecciones por Strongylida/parasitología , Strongylus/anatomía & histologíaRESUMEN
Two closed horse herds (Old Lot 4 and Field 24), infected since 1966 with Population B small strongyles resistant to thiabendazole (TBZ) and phenothiazine (PTZ), were terminated in February, March, and May, 2005. At necropsy, only the large endoparasites were identified and counted. The number of horses on pasture was 14 (239 days of age to 23 years old) for Old Lot 4 and two (3 to 20 years old) for Field 24. The time of the last antiparasitic treatment, relative to the year (2005) of necropsy, was 26 years for Old Lot 4 and 9 years for Field 24 horses. Gasterophilus intestinalis third instars (three to 113 specimens/horse) were found in all 16 horses and second instars (one to two) in two horses. Gasterophilus nasalis third instars (one to three) were recovered from five horses. Parascaris equorum infections (23 to 144) were in four horses (239 days to 4 years old). Strongylus vulgaris were present in the large intestine (one to 155) of 13 horses from 239 days to 23 years old and in the cranial mesenteric artery (two to 79) in 10 horses from 239 days to 23 years old. Strongylus edentatus were in the large intestine (two to 101) of 12 horses, ranging in age from 2.5 to 23 years old and in the ventral abdominal wall (one to 53) of six horses from 239 days to 21 years old. Specimens (seven to 872) of Anoplocephala perfoliata were in all horses. Oxyuris equi (one to 129) were recovered from seven horses (330 days to 23 years old). Thelazia lacrymalis (one to 85) infected the eyes of five horses (317 days to 11 years old).
Asunto(s)
Helmintiasis Animal/epidemiología , Enfermedades de los Caballos/epidemiología , Miasis/epidemiología , Infecciones Equinas por Strongyloidea/epidemiología , Animales , Ascaridoidea/clasificación , Ascaridoidea/aislamiento & purificación , Cestodos/clasificación , Cestodos/aislamiento & purificación , Dípteros/crecimiento & desarrollo , Femenino , Helmintiasis Animal/complicaciones , Helmintiasis Animal/parasitología , Enfermedades de los Caballos/parasitología , Caballos , Kentucky , Masculino , Miasis/parasitología , Prevalencia , Infecciones Equinas por Strongyloidea/complicaciones , Infecciones Equinas por Strongyloidea/parasitología , Strongylus/clasificación , Strongylus/aislamiento & purificación , Thelazioidea/clasificación , Thelazioidea/aislamiento & purificaciónRESUMEN
Population-S small strongyles have been studied since 1974 in central Kentucky in a closed Shetland pony breeding herd. The ponies were treated approximately every 8 weeks with cambendazole (1974-1978), oxibendazole (OBZ) (1978-1992), or pyrantel pamoate (PRT) (1992-1999). Small strongyles in the ponies have shown resistance to these compounds in field and critical tests. One purpose of this presentation was to compare different parameters for determination of effects on the small strongyle species in ponies after treatment, mainly with OBZ or PRT, from data in critical tests (n=112). Also, the objective was to report on relative changes in the composition of species of small strongyles during the period 1977 through 1999. The following entities were compared to evaluate the effect of OBZ- or PRT-treatment on the small strongyles: (1) numbers of specimens with eggs in utero--there were less gravid worms passed in the feces than recovered at necropsy for OBZ but the numbers of gravid worms were similar in both categories for PRT, (2) pre- and posttreatment counts of eggs per gram of feces (EPGs) and larvae per gram of feces (LPGs)--the reductions were greater for the counts of EPGs than LPGs for OBZ but not for PRT, and (3) pre- and posttreatment counts of EPGs versus % of worms removed--reductions of the former were greater than the latter for both compounds. As shown from data in this study, reduction of EPG counts post treatment indicated much greater drug activity than was actually demonstrated by removal of worms. One evident factor was the value of doing critical tests to verify posttreatment counts of EPGs as indicators of anthelmintic activity. Twenty-eight species of small strongyles were found. For the 20 most prevalent species in the study, two decreased, five remained unchanged, three increased and then became stationary, five increased but then decreased, and five increased progressively. Numbers of small strongyles were highest in 1987 and 1999.
Asunto(s)
Antinematodos/farmacología , Bencimidazoles/farmacología , Resistencia a Medicamentos/efectos de los fármacos , Pamoato de Pirantel/farmacología , Infecciones Equinas por Strongyloidea , Strongylus/efectos de los fármacos , Animales , Antinematodos/uso terapéutico , Bencimidazoles/uso terapéutico , Heces/parasitología , Femenino , Caballos , Kentucky , Recuento de Huevos de Parásitos/veterinaria , Pamoato de Pirantel/uso terapéutico , Infecciones Equinas por Strongyloidea/tratamiento farmacológico , Infecciones Equinas por Strongyloidea/parasitología , Strongylus/clasificación , Strongylus/aislamiento & purificaciónRESUMEN
Vinte e três espécies de nematóides estrongilídeos (18 Cyathostominae e cinco Strongylidae) foram coletadas de alíquotas, com aproximadamente, 10 por ciento do cólon dorsal de 33 eqüinos, provenientes da região de Janeiro. Cylicostephanus Longibursatus (90,9 por ciento; 1.078,4) C. goldi (81,8 por ciento; 236,9) e Cylicocyclus nassatus (75,8 por ciento; 39,1) foram as espécies mais prevalentes e com maior abundância média, respectivamente. Cylicostephanus longibur-satus apresentou o maior Ïndice de Dispersão (2.524.1) e menor Índice de Green (0,1), devido á presenca em quase todas as infracomunidades, e ao baixo nível de agregacã dos espécimes nas mesmas. Cinco infracomunidades (2, 3, 11, 24 e 25) apresentaram riqueza parasitária igual a quatro, porém os índice de Shannon e de uniformadade de Pielou foram distintos, devido á equitabilidade das infrapopulacões
Asunto(s)
Animales , Caballos/parasitología , Infecciones Equinas por Strongyloidea/parasitología , Colon/parasitología , Infecciones Equinas por Strongyloidea/diagnóstico , Strongylus/clasificación , Strongylus/aislamiento & purificación , Strongylus/patogenicidadRESUMEN
The study was performed to evaluate intensity of strongylid infection in stabled tarpans using the method of collecting worms after anthelmintic treatment and in wild tarpans from Popielne reserve on the basis of faecal examination. After treatment with ivermectin 12 cyathostomes and one large strongyle species were recovered from the faeces of two tarpans. The most abundant cyathostome species were C. catinatum, C. pateratum, C. longibursatum, C. nassatum and C. coronatus. A higher intensity of infections with small strongyles (cyathostomes) was found in stabled group than in the group from the reserve. Large strongyles were more prevalent in wild tarpans, with Strongylus vulgaris as most common species (66.7%), but the intensity of infection was low. The present results are compared with earlier studies of horses in Poland and other countries. The results confirm the stability of cyathostomes in different breed of horses over the world.
Asunto(s)
Caballos/parasitología , Infecciones Equinas por Strongyloidea/epidemiología , Strongylus/clasificación , Strongylus/aislamiento & purificación , Animales , Antiparasitarios/uso terapéutico , Heces/parasitología , Femenino , Ivermectina/uso terapéutico , Masculino , Recuento de Huevos de Parásitos , Polonia , Prevalencia , Infecciones Equinas por Strongyloidea/tratamiento farmacológico , Strongylus/fisiologíaRESUMEN
The sequence of the second internal transcribed spacer of the ribosomal DNA was determined for the following strongyloid nematodes: Cylicocyclus insignis, Chabertia ovina, Oesophagostomum venulosum, Cloacina communis, Cloacina hydriformis, Labiostrongylus labiostrongylus, Parazoniolaimus collaris, Macropostrongylus macropostrongylus, Macropostrongylus yorkei, Rugopharynx australis, Rugopharynx rosemariae, Macropostrongyloides baylisi, Oesophagostomoides longispicularis and Paramacropostrongylus toraliformis, and compared with published sequences for species of Strongylus and for Hypodontus macropi. The resultant phylogenetic trees supported current hypotheses based on morphological evidence for the separation of the families Strongylidae and Chabertiidae, but did not support the separation of the endemic Australian genera as a distinctive clade within the Chabertiidae. The implications of this finding for the phylogenetic origins of the Australian strongyloids are discussed.
Asunto(s)
ADN Ribosómico , Análisis de Secuencia de ADN , Strongyloidea/clasificación , Strongyloidea/genética , Animales , Australia , Secuencia de Bases , ADN de Helmintos , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Strongyloidea/anatomía & histología , Strongylus/clasificaciónRESUMEN
Genomic DNA was isolated from adult Strongylus asini collected from zebra. The second ribosomal transcribed spacer (ITS-2) was amplified and sequenced using polymerase chain reaction (PCR) based techniques. The DNA sequence was compared with previously published data for 3 related Strongylus species. A PCR-linked restriction fragment length polymorphism method allowed the 4 species to be differentiated unequivocally. The ITS-2 sequence of S. asini was found to be more similar to those of S. edentatus (87.1%) and S. equinus (95.3%) than to that of S vulgaris (73.9%). This result confirms that S. Asini and S vulgaris represent separate species and supports the retention of the 4 species within 1 genus.
Asunto(s)
ADN Ribosómico/genética , Filogenia , Strongylus/genética , Animales , Secuencia de Bases , Cartilla de ADN , ADN Ribosómico/química , Evolución Molecular , Femenino , Masculino , Datos de Secuencia Molecular , Namibia , Perisodáctilos/parasitología , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Mapeo Restrictivo , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Sudáfrica , Strongylus/clasificación , Strongylus/aislamiento & purificaciónRESUMEN
In the current study, molecular techniques were evaluated for the species identification of individual strongyle eggs. Adult worms of Strongylus edentatus, S. equinus and S. vulgaris were collected at necropsy from horses from Australia and the U.S.A. Genomic DNA was isolated and a ribosomal transcribed spacer (ITS-2) amplified and sequenced using polymerase chain reaction (PCR) techniques. The length of the ITS-2 sequence of S. edentatus, S. equinus and S. vulgaris ranged between 217 and 235 nucleotides. Extensive sequence analysis demonstrated a low degree (0-0.9%) of intraspecific variation in the ITS-2 for the Strongylus species examined, whereas the levels of interspecific differences (13-29%) were significantly greater. Interspecific differences in the ITS-2 sequences allowed unequivocal species identification of single worms and eggs using PCR-linked restriction fragment length polymorphism. These results demonstrate the potential of the ribosomal spacers as genetic markers for species identification of single strongyle eggs from horse faeces.