Prevalence and epidemiology of the major gastrointestinal parasites of horses in Perth, Western Australia

A survey was conducted on the prevalence of the major gastrointestinal parasites in 140 horses necropsied in Perth, Western Australia, during 1979 to 1982. Adult Strongylus vulgaris were found in 22.5 per cent of horses and verminous arteritis in 62.9 per cent. The peak worm prevalence was in November to January (summer). S edentatus had a similar prevalence and seasonality but S equinus was not found in this survey. Draschia megastoma and Habronema muscae were found in 66.2 per cent and 35.3 per cent of horses respectively. Infection is probably acquired in summer when 8 per cent of the Musca domestica in the vicinity of the stables carried third stage spiruroid larvae. Gasterophilus intestinalis and G nasalis occurred in 36.4 per cent and 22.1 per cent of the horses respectively and 52.1 per cent of horses were infected with one or both species. The peak prevalence of G intestinalis larvae occurred in December with a trough in February-April; the peak prevalence of G nasalis was in May with a trough in November-December. Parascaris equorum was found in 9.9 per cent of the horses and in 21.3 per cent of those less than three years old. Anoplocephala perfoliata was found in 4.9 per cent of the horses and most of these were in older horses.     

Prevalence of internal parasites in horses in critical tests of activity of parasiticides over a 28-year period (1956-1983) in Kentucky

The prevalence and number of naturally acquired gastrointestinal parasites were compiled for horses used in critical tests of activity of parasiticides over a 28-year period (1956-1983). Data are presented as follows: n = number of horses examined; % = mean prevalence; number in parentheses after % = aggregate mean number of parasites in infected horses. Parasites found were: bots (n = 513) - Gasterophilus intestinalis, 2nd instar, 61%(58); 3rd instar, 94%(168); G. nasalis, 2nd instar, 36%(28); 3rd instar, 81%(51); stomach worms (n = 200) - Habronema muscae, 65%(179); Draschia megastoma, 29%(95); Trichostrongylus axei, 46%(3000); ascarids (n = 513) - Parascaris equorum, mature, 50%(25); immature, 23%(33); tapeworms (n = 513), Anoplocephala perfoliata, 17%(15); A. magna, 14%(10); large strongyles (n = 487), Strongylus vulgaris, 84%(80); S. edentatus, 79%(101); S. equinus, 6%(14); small strongyles (n = 210), 100%(142,000); pinworms (Oxyuris equi), immature (n = 210), 78%(9000); mature (n = 506), 40%(62); Probstmayria vivipara (n = 210), 12%(10(7]; S. vulgaris in cranial mesenteric artery (n = 472), 89%(57). The majority of the horses examined were mixed lighthorse type but several Thoroughbreds were included. Ages varied from about 4 months to 20 years old, with most being approximately 1-3 years old. They probably had either no or infrequent previous treatment with parasiticides. Most of the horses were selected for presence of certain internal parasites, usually large strongyles, prior to usage in the critical tests.     

Prevalence of some internal parasites recovered at necropsy of Thoroughbreds born in 1982 in Kentucky

A total of 89 Thoroughbreds, 14 to 333 days old (born in 1982), were examined at necropsy for certain internal parasites during a 1-year-period, Mar 1, 1982, to Feb 28, 1983. The eyes of 73 of the horses and the cranial mesenteric arteries of 71 were examined. Specific interest was on prevalence of parasites according to month of the year and age of the horses at necropsy. Parasites recovered (first month-last month infected horse found) were as follows: Thelazia lacrymalis (eyes) immature and mature (June - February); Habronema/Draschia (lungs) immature (May - September); Habronema muscae (stomach) immature (July - February) and mature (September - February); Draschia megastoma (stomach) immature (August - December), mature (August - February), and lesions (September - February); Gasterophilus intestinalis (stomach) 2nd instars (July - February) and 3rd instars (August - February); Gasterophilus nasalis (stomach) 2nd instars (August - November) and 3rd instars (August - February); Parascaris equorum (lungs) immature (March - November), P equorum (small intestine) immature (March - February), and mature (July - February); Strongyloides westeri (small intestine) mature (March - September); Anoplocephala perfoliata (cecum) immature and mature (August - February); Strongylus vulgaris (cranial mesenteric artery) immature and mature (May - February). Other parasites recovered, but only from 1 or 2 horses each (months found in infected horses) were: Thelazia skrjabini (eyes) (October), Dictyocaulus arnfieldi (lungs) (January); Trichostrongylus axei (stomach) (October); Anoplocephala magna (small intestine) (October, November); S vulgaris (cecum) (November); Strongylus edentatus (cecum) (January); Setaria spp (abdominal cavity) (January). Influence of probable chemotherapy of the horses on prevalence of the parasites is discussed.     

Efficacy of moxidectin equine oral gel against endoscopically-confirmed Gasterophilus nasalis and Gasterophilus intestinalis (Diptera: Oestridae) infections in horses

A 3 m, video gastroscope was used to screen 47 horses suspected of being naturally infected with equine bot larvae. 17 of 47 (36.2%) candidate horses harbored Gasterophilus nasalis larvae in the proximal duodenum and 46 of 47 (97.9%) had G. intestinalis larvae in the stomach. All horses infected with G. nasalis had concurrent infections with G. intestinalis. 14 horses with dual infections were allocated randomly to two treatment groups. Seven horses in Group 1 received 2% moxidectin oral gel once at a dosage of 0.4 mg/kg bodyweight (BW), and seven horses in Group 2 were untreated controls. 14 days after treatment, all horses were necropsied and the stomach and proximal duodenum harvested from each. Bot larvae were recovered, identified to species and instar, and counted. At the label dosage, moxidectin oral gel was 100 and 97.6% effective (P < 0.05) against third-instar G. nasalis and G. intestinalis, respectively. In addition to demonstrating the boticidal efficacy of moxidectin, this trial illustrated that gastroscopy/duodenoscopy is a feasible method for confirming infections with different species of bot larvae in the horse.     

Critical tests of morantel-trichlorfon paste formulation against internal parasites of the horse

Critical tests were completed on six horses to evaluate the antiparasitic activity of a paste formulation mixture of morantel citrate and trichlorfon, administered intraorally at the dose rate of 6 mg morantel base kg-1 and trichlorfon at 30 mg kg-1. Aggregate average removals were: 78% for two horses infected with 2nd instar Gasterophilus intestinalis; 100% for one infected with 2nd instar G. nasalis; 96% for six infected with 3rd instar G. intestinalis; 100% for four infected with 3rd instar G. nasalis; 100% for five infected with Parascaris equorum; 100% for one infected with mature Oxyuris equi; 100% for five infected with Strongylus vulgaris; 72% for five infected with S. edentatus; and partial removal (25%) of Anoplocephala perfoliata infection from one infected animal. Pre- and post-treatment EPG and LPG data indicated a reduction of 97% of the mature small strongyle infections. Evidence of toxicosis was not observed in any of the horses.     

Common internal parasites found in the stomach, large intestine, and cranial mesenteric artery of thoroughbreds in Kentucky at necropsy (1985 to 1986)

A total of 278 Thoroughbreds (less than 1 to 31 years old) were examined at necropsy (July 9, 1985, to Feb 2, 1986) in Kentucky for various internal parasites. Examination was not made of all the horses for each of the parasites. Specific parasites recovered from the stomach of foals (n = 30) and yearlings and older horses (n = 96) and percentage (in parentheses) of each age category infected, respectively, were as follows: Gasterophilus intestinalis 2nd instar (53% and 32%) and 3rd instar (37% and 24%); G nasalis 2nd instar (7% and 8%) and 3rd instar (7% and 10%); Habronema spp immature (7% and 13%); H muscae (3% and 8%); Draschia megastoma (3% and 5%) and lesions (0% and 2%); and Trichostrongylus axei (0% and 3%). Parasites in the large intestine included Anoplocephala perfoliata, which was found in the cecum of 30% of the foals (n = 87) and in 60% of the yearlings and older horses (n = 186). Probstmayria vivipara and immature Oxyuris equi were not found in the colon and rectum of any of the horses (n = 53 foals and n = 101 yearlings and older); mature O equi were not sought. Examination of the cranial mesenteric artery for Strongylus vulgaris revealed immature and/or mature specimens in 9% of foals (n = 87) and 14% of yearlings (n = 44); lesions of S vulgaris were present in 25% of foals (n = 87) and 34% of yearlings (n = 44).     

Prevalence of Helicobacter equorum in faecal samples from horses and humans

Recently, a new enterohepatic Helicobacter species, H. equorum, was isolated from faecal samples of two clinically healthy horses. At the onset of this study, nothing was known about the prevalence of this organism in horses, nor was there any information available on the possible zoonotic character of this agent. This study aimed to determine the prevalence of H. equorum in faecal samples from equine and human origin. Therefore, faecal samples of 120 healthy privately owned horses, 227 healthy riding-school horses and 239 hospitalised horses were screened for H. equorum-DNA by means of a PCR amplifying a 1074-bp fragment of the 23S rRNA gene with primers specific for H. equorum. The vast majority of the hospitalised horses were under treatment with an antimicrobial agent at the moment of sampling, while the other horses had not been treated with an antimicrobial agent in the 14 days preceding the sampling. Stool samples of 531 humans suffering from gastro-intestinal disease and 100 clinically healthy humans were likewise examined. H. equorum-DNA was demonstrated in faeces from 0.8% of the privately owned horses, 3.1% of the riding-school horses and 7.9% of the hospitalised horses. The prevalence of H. equorum was significantly higher in hospitalised than in healthy, privately owned horses (P=0.02). H. equorum-DNA was not detected in human samples. These results indicate that the prevalence of H. equorum in horses may be influenced by the health status of the investigated horse population and/or by antimicrobial treatment. We may additionally assume that this micro-organism does not commonly infect humans.     

Species composition of Gasterophilus spp. (Diptera, Oestridae) causing equine gastric myiasis in southern Italy: parasite biodiversity and risks for extinction

Horse gastrointestinal myiasis caused by larvae of Gasterophilus spp. (Diptera, Oestridae) flies has a worldwide distribution and, where present, it is primarily caused by larvae of Gasterophilus intestinalis and Gasterophilus nasalis. Other species, i.e., Gasterophilus inermis, Gasterophilus pecorum and Gasterophilus haemorrhoidalis, present in different or in the same regions of the gastrointestinal tract, were only occasionally reported in very limited areas of eastern European Countries and in central Italy. With the aim to contribute data on the species composition of Gasterophilus and on the seasonal variation of the infection pattern in southern Italy, 152 native horses were necropsied from January to December 2003 and Gasterophilus larvae were collected from the stomach, the small intestine and the rectum of each of them. On the whole, 125 (82.2%) horses were infected by larvae of Gasterophilus spp. and 214 second stage larvae (L2) and 13,342 third stage larvae (L3) collected. Five species of Gasterophilus were identified with the following prevalence: G. intestinalis=95.2%, G. nasalis=44.8%, G. inermis=15.2%, G. pecorum=2.6% and G. haemorrhoidalis=0.8%. L3 were retrieved throughout the observation period with the highest mean burdens from January to August 2003 while the lowest mean was registered from September to November 2003. L2 were collected in February-March 2003 and from September to December 2003. The majority of the animals (n=66, 43.4%) were infected with a single Gasterophilus species, however, 45 animals (29.6%) harboured 2 species, 12 animals (7.9%) 3 species and 2 animals (1.3%) 4 species. The trend of abundance in the L3 of G. intestinalis and G. nasalis, the most represented species, was highly concordant (r=0.5, p<0.001). A retrospective comparison of our results and of other data from four seasons of observation (1983-1986) in central Italy showed that the number of G. inermis, G. pecorum and G. haemorrhoidalis have been decreasing relative to G. intestinalis and G. nasalis which may suggest tendency toward the extinction of the three former species of Gasterophilus.     

Equine parascarosis under the tropical weather conditions of Ethiopia: a coprological and postmortem study

A cross-sectional coprological survey in the regions of Ada, Akaki, Bereh and Boset, and a retrospective postmortem investigation were conducted to study the epidemiology of Parascaris equorum in donkeys and horses in Ethiopia. Faecal samples from 803 working donkeys and 402 horses were collected, and the numbers of worms recovered from 112 donkeys examined postmortem between 1995 and 2004 were analysed. There was a high prevalence of infection and faecal egg output of P equorum in both donkeys and horses, and the severity of the infection in donkeys was increased irrespective of their age. The prevalence of the infection in the donkeys was 51.1 per cent and in the horses 16.2 per cent, and the prevalence in the donkeys examined postmortem was 55 per cent. There was no significant difference between different age groups of donkeys in either the prevalence or the intensity of the infection. The prevalence of the infection was significantly higher in the Ada and Akaki regions than in the Bereh and Boset regions.     

Critical and controlled tests of activity of moxidectin (CL 301,423) against natural infections of internal parasites of equids.

The activity of moxidectin was evaluated in 1988 and 1989 against natural infections of internal parasites in 20 critical tests (n = 20 equids) and three controlled tests (n = 20 equids). Two formulations, injectable administered intramuscularly (i.m.) or intraorally (i.o.) and gel i.o., were given at dose rates of 0.2, 0.3 or 0.4 mg kg-1 body weight. For the critical tests (all three dose rates evaluated), removals of second instar Gasterophilus intestinalis were 93-100%, except (89%) for the injectable formulation (i.m.) at 0.2 mg kg-1. Removals of third instar G. intestinalis were 88-100% for the injectable formulation given i.m. or i.o. and 93-100% for the gel formulation, except (53%) for one batch (0.4 mg kg-1). Activity was 100% for third instar Gasterophilus nasalis, Parascaris equorum, Strongylus vulgaris and Strongylus edentatus. For Oxyuris equi, removals were 91-100%, except (27%) for one batch of the injectable formulation given i.o. at 0.3 mg kg-1. There was apparent activity against migrating S. vulgaris and S. edentatus at various dose rates and routes of administration for both formulations. At necropsy, there were local reactions observed at the injection site of three equids. In the controlled tests, dose rates were 0.2 or 0.4 mg kg-1. Removal of third instar G. intestinalis was highest for the injectable formulation given i.m. All formulations and dose rates were highly effective against S. vulgaris and S. edentatus, but variable and incomplete against O. equi. Removal was excellent on Habronema muscae and on migrating S. vulgaris and S. edentatus, although incomplete on S. vulgaris. Gasterophilus nasalis third instars and P. equorum were present in low numbers in some non-treated equids, but none were recovered from treated equids. Toxicosis was not evident.     

Occurrence of second and third instars of Gasterophilus intestinalis and Gasterophilus nasalis in stomachs of horses in Kentucky.

The occurrence of 2nd and 3rd instars of Gasterophilus intestinalis and Gasterophilus nasalis was determined in 476 horses during the 22-year period from 1951 to 1973. Overall, G intestinalis infected 98.7% of the horses and averaged 168/horse; whereas G nasalis infected 80.7% of the horses and averaged 52/horse. Aggregate average total numbers for G intestinalis ranged from a low of 50 in September to a high of 229 in March, and for G nasalis, from a low of 14 in September to a high of 82 in February. Horses were infected by 2nd or 3rd instars of both species on a year-round basis. Differentiation between the instars provided insight into the dynamics of the infections. For G intestinalis, the data indicated (1) 2nd instars from the previous year's generation of flies continue to arrive in the stomach until April; (2) arrival of the current year's crop of 2nd instars starts in July; and (3) 3rd instars from the previous year's generation of flies are not voided in appreciable numbers until August, when numbers of the current year's crop of 3rd instars appear in the stomach. For G nasalis, the data indicated (1) arrival in the stomach of the current year's generation of 2nd instars starts in July and terminates in January and (2) 3rd instars from the previous year's generation of flies are voided over a period beginning in March and extending into August, when the current year's crop of 3rd instars begin to appear. Acquisition of infections of horses with G intestinalis is nearly a year-round process, except for April, because of the persistence of viable larvae in eggs for a prolonged period after development and fly activity has ceased in the fall. In contrast, infection with G nasalis is interrupted between December and May, because eggs hatch naturally after a short period of development, and fly activity ceases in the fall.     

Gastrointestinal parasites of working donkeys of Ethiopia

The general prevalence and population composition of gastrointestinal and pulmonary helminths of working donkeys were studied. For the purpose 2935 working donkeys were coprologically examined for nematode and cestode, and 215 donkeys for trematode infections. Seven donkeys that died due to various health problems or were euthanased on a welfare ground were necropsied and the parasites were recovered and identified to the species level. The study was conducted during the periods 1996-1999. Coprological examination revealed 99% strongyle, 80% Fasciola, 51% Parascaris, 30% Gastrodiscus, 11% Strongyloides westeri, 8% cestodes and 2% Oxyuris equi infection prevalence. Over 55% of donkeys had more than 1000 eggs per gram of faeces (epg). Forty two different species of parasites consisting of 33 nematodes, 3 trematodes, 3 cestodes and 3 arthropod larvae were identified from postmortem examined donkeys. Among the nematodes 17 species of Cyathostominae and 7 species of Strongylinae were identified. Other parasites identified include, Habronema muscae, Draschia megastoma, Trichostrongylus axei, Strongyloides westeri, Anoplocephala perfoliata, Anoplocephala magna, Anoplocephaloides (Paranoplocephala) mamillana, Parascaris equorum, Fasciola hepatica, Fasciola gigantica, Gastrodiscus aegyptiacus, Dictyocaulus arnfieldi, Oxyuris equi, Probstmayria vivipara, Gasterophilus intestinalis, Gasterophilus nasalis, Rhinoestrus uzbekistanicus and Setaria equina. This study revealed that working donkeys in Ethiopia are infected with a range of helminths and arthropod larvae, which are representatives of the important pathogenic parasites found in equids worldwide.     

Efficacy of ivermectin (22,23-dihydroavermectin B1) against gastrointestinal parasites in ponies

The controlled test method was used to evaluate the antiparasitic efficacy of IM inoculated 22,23-dihydroavermectin B1 (ivermectin) against gastrointestinal parasites of horses (ponies). Parasite infections were naturally acquired in southern Louisiana. Dose levels of the drug tested were 0.2 mg/kg, 0.3 mg/kg, and 0.5 mg/kg. Ivermectin at all dose levels tested had an efficacy greater than 97% (P less than 0.05) against Gasterophilus intestinalis larvae, Trichostrongylus axei, Oxyuris equi larvae, Strongylus vulgaris, S edentatus, 15 species of small strongyles, and small strongyle larvae. Ponies were less uniformly infected with Habronema sp larvae, G nasalis larvae, Parascaris equorum, O equi adults, Anoplocephala perfoliata, S equinus, and 11 small strongyle species, and statistical analysis was not possible to do. However, observations indicate that the drug was also highly effective against these species. There were no gross or clinical reactions observed in treated animals. Dissections of the injection sites revealed spindle-shaped lesions, 3 to 5 cm long, in a few ponies in all treatment groups, including those given the placebo injection.     

Impaired efficacy of ivermectin against Parascaris equorum, and both ivermectin and pyrantel against strongyle infections in trotter foals in Finland

In order to assess the resistance situation against macrocyclic lactones in Parascaris equorum and against tetrahydropyrimidine derivatives in strongyles in Finnish trotter horses, 112 foals on 18 farms, mostly 1 year old, were examined for these parasites with a modified McMaster faecal flotation method. P. equorum positive foals (n=24) were given ivermectin orally at a dose of 200 μg/kg b.w., while strongyle positive but P. equorum negative foals (n=38) received pyrantel embonate orally at a dose of 19 mg/kg. Sixteen P. equorum infected foals, treated with ivermectin, also harboured strongyles. During the anthelmintic treatment visit to the farm, Faecal Egg Count Reduction Test (FECRT) reference (first) samples were collected. Fourteen days later, the second sampling (reduction samples) was done. The FECR was calculated for each foal/parasite combination. The reduction efficacies of ivermectin against P. equorum (mean 52%, calculated from the individual egg count reductions) and pyrantel against strongyles (43%) were strongly indicative of widespread resistance. Also indication of ivermectin resistance among strongyles was seen. The widespread use of anthelmintics for Finnish horses obviously has resulted in resistance, as has happened elsewhere, too.     

Gastrointestinal Parasites of Stabled and Grazing Horses in Central and Northern Greece

The aim of this investigation was to compare parasites found in feces from stabled and grazing horses in Greece. For this, a total of 223 fecal samples were collected from horses from various parts of Central and Northern Greece. One hundred fifty were stabled and 73 were grazing horses, used for riding, working, or breeding. One hundred came from seven riding clubs, 73 from one breeding farm, and 50 were work horses from five farms. Parasitologic investigation was performed by applying three fecal examination techniques (Teleman's, zinc flotation, and stained smears) to detect ova, larvae, and oocysts of parasites. It was found that 77 the 223 horses (34.5%) in the study were infected with one or more parasite species. In the stabled horses, the most common parasites detected were eggs of strongyles, Strongyloides spp, Anoplocephala spp, Habronema spp, and Parascaris equorum and oocysts of Eimeria spp and Cryptosporidium spp; in the grazing horses, Anoplocephala spp. Strongyles were significantly more prevalent in the group of stabled horses than in the other group (P < .05). The results of the current study demonstrate that parasite infection is highly prevalent in horses in Greece.     

Critical test evaluation of butamisole against gastrointestinal parasites of horses and ponies.

A critical test was performed to evaluate the anthelmintic properties of an injectable butamisole formulation and to compare the efficiency with that of a commercially available piperazine-thiabendazole anthelmintic. The test was done in 10 horses and 15 ponies with naturally acquired parasitic infections. Butamisole was administered at the dose level of 2.5 or 3.75 mg/kg of body weight by either subcutaneous or deep intramuscular injection. Given at the dose level of 2.5 mg/kg, butamisole was highly effective (99%) against Strongylus vulgaris and moderately effective (49%) against Parascaris equorum. At the 3.75 mg/kg dose rate, butamisole was highly effective against both S vulgaris (97%) and P equorum (94%). Butamisole had limited efficacy against other parasite species. Signs of toxicosis, long-term swelling of the injection sites, or tissue damage were not seen after injection.     

Prevalence of selected species of internal parasites in equids at necropsy in central Kentucky (1995-1999)

A survey to determine current prevalence of several species of endoparasites in equids (n=350) at necropsy was conducted at the Livestock Disease Diagnostic Center in central Kentucky (1995-1999). Thelazia lacrymalis were found in 42% of the 1- to 4-year olds (n=132), which was the only age group examined for these parasites. Five- to 30-year olds (n=157), examined for Onchocerca spp. worms/lesions, had a prevalence of 24%. In > or =1-year olds (n=324), the infection rate for Gasterophilus intestinalis was 12% for second instars and 14% for third instars and for Gasterophilus nasalis was 2% for second instars and 2% for third instars. For Anoplocephala perfoliata (n=268 equids), prevalence was 52%. Data were compiled for the equids according to breed, age, sex, month of necropsy, and number of parasites. Arterial lesions caused by migrating Strongylus vulgaris larvae were observed in a low number (3 of 52) of equids. Specific examination for Parascaris equorum revealed that 46% of 13 weanlings and 10% of 20 older horses were infected. Anoplocephala magna were found in one of the weanlings. Compared to previous studies (about 15-25 years ago) in Kentucky, the present survey indicated the genera Onchocerca and Gasterophilus greatly declined but Thelazia, Anoplocephala, and Parascaris did not.     

Prevalence of Ocular Disorders in an Indian Population of Horses

The objective of this clinical study was to report the prevalence of ocular disorders in a large population of horses from the Indian army. Both eyes of 500 horses were examined using a direct ophthalmoscope and by a transillumination procedure. Intraocular pressures were measured in several study horses. Fluorescein dye, Schirmer tear test, and menace testing were performed when indicated. Corneal culture swabs were collected from horses affected with corneal ulcers found on ophthalmoscopic examination. A total of 100 horses were found to be affected with some form of ocular disorder. The eye problems recorded were congenital eye lid disorders (2%) and included a subcutaneous cyst in the lower eye lid and slit in upper eye lid; conjunctivitis (12%); chronic interstitial keratitis (30%); a parasite in the anterior chamber (1%), which was however not removed for genus and species identification; phthisis bulbi (1%); uveitis (24%); glaucoma (13%); cataracts (3%); unilateral retinal hemorrhage (1%); luxation of cataractous lens (3%); posterior synechia (2%); and corneal ulceration (8%). Pseudomonas spp was the most common bacteria identified in horses affected with corneal ulceration. Vision-threatening ocular disorders are high in Indian army horses; this is a cause of major concern for the rider and the horse and, therefore, it is important to include ocular examination in horses as part of a routine and complete physical examination.     

The prevalence of Gasterophilus intestinalis and G nasalis in horses in Ireland.

During the months October-May inclusive 90-8% of horses slaughtered at an abattoir near Dublin and 66-9% of those at an abattoir near Belfast were infected with Gasterophilus intestinalis; 28-6% of horses at the former abattoir harboured G nasalis while none of the horses examined at the latter abattoir was found to be infected with this species.     

Molecular cross-sectional survey of gastric habronemosis in horses

Gastric habronemosis of horses caused by Habronema microstoma and Habronema muscae (Nematoda, Spirurida) is characterized by catarrhal gastritis, diarrhoea, progressive weight loss and ulcers. Despite its importance in the equine industry and in clinical practice, knowledge of the epidemiology of this infection is still incomplete as diagnosis in live animals is challenging. A two-step semi-nested PCR assay using ribosomal DNA (rDNA) markers has recently been used for the molecular diagnosis in vivo of gastric habronemosis based on the detection of H. microstoma and/or H. muscae DNA in equine faeces. To evaluate the field efficacy of this assay, a molecular epidemiological survey was carried out on equid gastric habronemosis in central Italy. One hundred and fifty-three individual faecal samples were collected from live native horses and subjected to both coprological examination and the two-step semi-nested PCR. When flotation procedures were performed no horse tested positive for Habronema spp. larvated eggs while 96 animals (61.2%) were positive for other endoparasites (i.e. strongyles, oxyurids, ascarids). Two-step semi-nested PCR detected 86 samples (53.6%) that were positive for H. microstoma and/or H. muscae DNA. H. microstoma prevalences showed statistically significant differences; the highest prevalence was observed in horses infected by other gastrointestinal parasites and concomitantly by H. muscae. No statistical differences were found between the prevalence of Habronema spp. infection and sex, age, breeding management, and antiparasitic treatments. This field survey provided further information on habronemosis and its epidemiology.