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).

Onchocerca spp: frequency in Thoroughbreds at necropsy in Kentucky.

Examination of the ligamentum nuchae for Onchocerca spp was completed in 523 Thoroughbreds (1 to 29 years old) at necropsy in Kentucky during a 13-month period (1984 to 1985). Onchocerca spp were found in 306 (59%) of the horses. Frequencies of this parasite were 3%, 17%, 40%, 43%, and 42% in 1-, 2-, 3-, 4-, and 5-year-old horses, respectively. For 6- to 29-year-old horses, frequency varied from 71% to 100%, except for 26-year-old horses (50%); 87% of the 304 horses examined in the 6- to 29-year-old age groups was infected. The suspensory ligaments and flexor tendons from fetlocks (thoracic limb only) of 100 Thoroughbreds (3 to 24 years old) were examined at necropsy during a 4-month period (1984) for Onchocerca spp. Infected horses were not found.

Eyeworms (Thelazia lacrymalis) in one- to four-year-old Thoroughbreds at necropsy in Kentucky (1984 to 1985).

From Mar 1, 1984, to Feb 28, 1985, both eyes from 189 one- to four-year-old Thoroughbreds (88 males, 90 females, and 11 geldings) in Kentucky were examined at necropsy for eyeworms. Thelazia lacrymalis was recovered from 45% of 1-year-old horses, 26% of 2-year-old horses, 45% of 3-year-old horses, and 50% of 4-year-old horses; overall, 43% of 1- to 4-year old horses were infected. Prevalence of eyeworms in horses in the present study was comparable with that in horses of similar ages examined at necropsy in Kentucky in 2 previous studies (1975 to 1976 and in 1979), except for the lower percentage of infected 2-year-old Thoroughbreds in the present study.

Lungworms (Dictyocaulus arnfieldi): prevalence in live equids in Kentucky.

Prevalence of natural infections of the lungworm, Dictyocaulus arnfieldi, was investigated in Kentucky in 5,437 live equids (horses, ponies, and asses) on 91 farms by examination of fecal samples over a 15-month-period from January 28, 1983 to April 19, 1984. For the 91 farms investigated, asses only were examined on 1 farm; for the other 90 farms, examinations were made of horses on all of them, of ponies on 4 farms, and of asses on 9 farms. Larvae of D arnfieldi were found in fecal samples of 112 (2%) of 5,379 horses on the 90 farms of which 38% had greater than or equal to 1 infected animal; none of 19 ponies examined was infected. For 39 asses (donkeys and mules) examined, 21 (54%) were infected; infected asses were present on 80% of the 10 farms on which they were examined. The equids, excluding asses, that were examined and the percentage (in parentheses) infected with D arnfieldi included 4,329 (2%) Thoroughbreds, 684 (2%) Standardbreds, 78 (0%) American Saddle Horses, and 307 (3%) miscellaneous (other breeds or mixed breeds of horses and ponies). Equids were separated into 3 categories relative to previous treatment with ivermectin: A (no treatment), B (treatment), and C (treatment unknown).(ABSTRACT TRUNCATED AT 250 WORDS)

Parasites in lungs of dead equids in Kentucky: emphasis on Dictyocaulus arnfieldi.

Prevalence of natural infections of parasites from the lungs of 488 dead Thoroughbreds in Kentucky was investigated. The horses varied from 1 to 32 years of age; 419 horses were from 215 farms and 69 horses were from 68 individual sources for which a specific farm was not identified. Examinations of the lungs were made from Mar 1, 1983 through Feb 29, 1984. Dictyocaulus arnfieldi was recovered from 56 (11%) of the horses. Other parasites found were larvae of Parascaris equorum in 37 (8%) and of Habronema/Draschia in 67 (14%) of the horses. The possible effect of ivermectin treatment on the prevalence of D arnfieldi in the lungs is discussed. Presence of D arnfieldi in 20 other selected dead equids was also investigated.

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.

Equine congenital defects.

In a 13-year survey of equine congenital defects that resulted in death or required euthanasia in central Kentucky, necropsies were performed on 608 deformed fetuses or newborn foals. The following congenital anomalies were observed: contracted foal syndrome (33.2%), miscellaneous limb contraction (20%), multiple defects (5.3%), microphthalmia (4.6%), craniofacial malformations (4.3%), cleft palate (4.0%), heart defects (3.5%), umbilical defects (3.5%), and hydrocephalus (3.0%). Eleven less frequently occurring anomalies constituted the balance of the congenital defects in fetuses and newborn foals.

Teratogenicity in swine of the tobacco alkaloid anabasine isolated from Nicotiana glauca.

Nicotiana glauca, wild tree tobacco, induces arthrogrypotic congenital defects in piglets similar to those induced by Nicotiana tabacum, common tobacco. The present work was conducted to isolate the principal alkaloid of N. glauca, anabasine, in large quantity and good purity and to test the teratogenicity of the compound in pigs. The isolated compound was established to be anabasine and to be of suitable purity by chemical characterization. It proved to be teratogenic. Typical arthrogrypotic defects were induced in 21 of 26 offspring (three of three litters) when dams ingested 2.6 mg of the compound per kg body weight twice daily during the 43rd-53rd days of gestation. Of three dams dosed with 1.66 g/kg/day of the dried plant material during the 43rd-53rd days, one delivered deformed offspring representing one-third of all offspring in that group. These arthrogrypotic defects induced by anabasine were indistinguishable clinically from defects induced by either N. glauca or N. tabacum. In addition, anabasine at a dose of 2.6 mg/kg twice daily or N. glauca plant material at 1.66 gm/kg daily induced cleft palate in over three-fourths of offspring (100% of litters) when dams ingested either during the 30th-37th days of gestation or during longer periods that included those days.

Prevalence of Anoplocephala perfoliata and lesions of Draschia megastoma in Thoroughbreds in Kentucky at necropsy.

A total of 396 Thoroughbreds (86 males, 293 females, and 17 geldings) in Kentucky, 1 to 30 years of age, were examined at necropsy for presence of Anoplocephala perfoliata (2 female horses were not examined) in the cecum for lesions of Draschia megastoma in the stomach, during the 1-year period of Mar 1, 1982 through Feb 28, 1983. Prevalence of A perfoliata was 53% and of lesions of D megastoma was 63%. All lesions of D megastoma were partially or entirely in the glandular region of the stomach. Distances of the midpoint of these lesions from the margo plicatus varied from 0 to 290 mm. The center of about 88% of the lesions was within 50 mm of the margo plicatus . Measurements of the size of the lesions, exclusive of masses, indicated that about 95% were less than or equal to 50 mm in diameter. There appeared to be a higher infection rate of lesions of D megastoma in younger horses (81% in 1 to 7 year olds) than in older horses (41% in 8 to 30 year olds) with a few exceptions.

Teratogenicity and toxicity of wild tree tobacco, Nicotiana glauca in sheep.

Collections of Nicotiana glauca containing from 0.45-1.14 mg anabasine per gram dry weight of plant induced moderate - severe toxic signs in pregnant ewes and teratogenic effects in their offspring when the ewes were given single daily doses of the plant that provided from 1.66 - 3.42 mg anabasine per kg body weight. Toxic signs included excess salivation, irregular gait, wobbling while walking or standing, recumbency and death. Teratogenic effects occurred in offspring from animals fed those doses the 30th - 60th day of gestation. Terata expression included limb defects such as a fixed excessive carpal flexure with or without lateral or medial rotation of fore or rear limbs, lordosis, irregular shaped head or cleft palate.

Parasites in Kentucky Thoroughbreds at necropsy: emphasis on stomach worms and tapeworms.

A total of 363 Thoroughbreds (62 males, 292 females, and 9 geldings), 1 to 26 years of age, were examined at necropsy for internal parasites for about a 12-month period from February 1981 through February 1982. Emphasis was on examining the stomach for nematodes and the small intestine and cecum for tapeworms. Parasites recovered from the stomach and infection rates were: Habronema spp--immature (24%), H muscae--adult (38%), Draschia megastoma--immature (13%), D megastoma--adult (62%), and Trichostrongylus axei--adult (4%); lesions caused by D megastoma were found upon gross observation in 58% of the stomachs. The tapeworm, Anoplocephala perfoliata, was recovered from 54% of the horses; A magna was not found. There was no obvious difference in infection rates of the stomach worms and tapeworms according to age or sex of the horses. Seasonal differences were apparent only for immature Habronema spp and immature D megastoma for which infection rates began increasing in June, peaking in October, and declining thereafter. Presence of 4 additional species of parasites was recorded, but only a cursory examination was made for them. These were the large strongyles, Strongylus vulgaris, S edentatus, and S equinus, from the cecum and a filariid, Setaria spp (probably S equina), from the abdominal cavity, for which recovery rates from the horses were 8%, 8%, 1%, and 7%, respectively.

Congenital deformities in swine induced by wild tree tobacco, Nicotiana glauca.

Eighty-four of 147 piglets from 20 purebred Hampshire gilts that were bred to purebred Hampshire boars and then fed Nicotiana glauca during various periods of gestation were congenitally deformed. The deformities occurred in piglets from gilts on experiments in 3 separate years during which 4 different collections of the plant were fed. The deformities included various arthrogrypotic limb deviations and palate closure defects. Arthrogrypotic limbs had excessive flexure of pastern or carpal joints, medial rotation, or a combination of these effects. There were no gross visceral defects nor histopathologic changes in examined tissue. Expression of deformities varied as a function of gestation period. Palate closure defects, for example, occurred only in offspring from sows fed prior to gestation day 35. The limb deformities induced by N. glauca in piglets were similar to those reported by others and assumed, or known from feeding trials, to have been induced by maternal Nicotiana tabacum stalk ingestion. By contrast palate defects were not reported in piglets from maternal N. tabacum ingestion, but were of high incidence in the present work from maternal N. glauca ingestion. The suspect teratogen, anabasine, the principle piperidine alkaloid of N. glauca, varied in concentration among the collections fed. However dosages were maintained in each animal regardless of collection fed that resulted in daily toxicity signs indicative of anabasine toxicosis. The signs included depression, tremors, third eyelid closure, irregular gait and recumbency.

Prevalence of Strongylus vulgaris and Parascaris equorum in Kentucky thoroughbreds at necropsy.

At necropsy of 49 Thoroughbreds from farms with generally good parasite control programs in central Kentucky, examination was specifically made for presence of Strongylus vulgaris in all of the horses and of Parascaris equorum in 21 of them. None of the deaths of the horses was caused by infections of internal parasites. Visceral arteries were examined for specimens of S vulgaris and lesions related to migrating stages of this parasite. Contents of the small intestines were examined for P equorum. Specimens of S vulgaris were recovered from 19 (39%) horses, and arterial lesions were observed in 24 (49%) of them. Parascaris equorum was found in 9 (43%) horses. Both parasites were found to persist in generally low numbers on farms in spite of their parasite control programs applied in recent years.

Nicotiana glauca-induced congenital deformities in calves: clinical and pathologic aspects.

Seven calves born to 7 cows fed Nicotiana glauca during portions of the 1st trimester of gestation were deformed at birth. Deformities increased in severity as the calves aged. At birth, calves typically had arthrogryposis of the forelimbs or curvature of the spine; severity varied among calves. In 4 calves necropsied at about 15 months of age, there was general malpositioning and misalignment of the distal ends of the radius and ulna and the proximal ends of the metacarpal bones. Carpal joints were severely affected, fetlock joints were moderately affected, and pastern joints were slightly affected, with lateral rotation of forelimbs common; severity varied among calves. In 1 of the 4 calves, there was moderate torticollis and scoliosis resulting from wedging of some of the cervical and thoracic vertebrae and abnormal cranial curvature of the left thoracic ribs. Histologic changes were not noticed in muscle, brain, spinal cord, or endocrine organs of the 4 calves.

Teratogenicity and toxicity of coniine in cows, ewes, and mares.

Cows, ewes, and mares varied considerably in susceptibility to toxicoses from the oral administration of the piperidine alkaloid, coniine. Cows were most susceptible and ewes least. Only calves had teratogenic effects from maternal administration of coniine during gestation; lambs and foals were apparently resistant. Results suggest that the marked differences between cattle and sheep are probably not due to variation in gut absorption or rumen metabolism.