Ovine coccidiosis: the pathology of Eimeria crandallis infection.

Doses of sporulated oocysts of Eimeria crandallis ranging from 50 to 300,000,000 were given to 27 housed lambs aged between 4 and 12 weeks that had been reared coccidia-free. Lambs were killed between 1 and 22 days after inoculation and their tissues examined histologically. Clinical effects were very variable and not closely related to inoculating dose. Some lambs showed intermittent diarrhoea, sometimes watery and sometimes containing muco-fibrinous material, either in the form of intestinal casts or as a greyish discoloration. Loss of surface epithelial cells and villus atrophy in the small intestine were associated with first generation meronts and the release of merozoites from them; in some lambs apoptosis of crypt cells also occurred, leading to crypt atrophy. Severe diffuse crypt hyperplasia was associated with pro-gamonts in the small and large intestines. In a minority of the lambs this stage was associated with what appeared to be crypt destruction by host cells in the lamina propria, leading in some cases to denudation and severe diarrhoea.

Observations on the endogenous stages of Eimeria crandallis in domestic lambs (Ovis aries).

Lambs reared coccidia-free were inoculated orally with various numbers of sporulated oocysts of E. crandallis and were killed between 1 and 22 days after inoculation; tissues were examined histologically. Sporozoites were seen 1, 2 and 3 days after inoculation (DAI) in crypt epithelial cells in the mid-jejunum. Infected cells migrated into the lamina propria where the parasite within them developed into a first-generation meront containing about 250,000 merozoites at 10 DAI. A second generation of meronts was seen at 10-12 DAI, each containing up to about 10 merozoites, situated mainly at the bases of crypts in the jejunum and ileum but also in the caecum. From 11 DAI pro-gamonts were seen which were enveloped by the host cell nucleus and which divided in synchrony with the host cell for an undetermined number of generations. Mature gamonts began to develop from them by 16 DAI. Oocyst output began at 16 DAI and rose to a peak at about 22 DAI. Up to 10(8) oocysts were produced per oocyst inoculated. They showed wide variation in size and colour.

Tissue-invading ciliates associated with chronic colitis in a horse.

Ciliates resembling Polymorphella ampulla (Dogiel, 1929) were found in large numbers in the crypts and lamina propria of the caecum and colon of a one-year-old Thoroughbred gelding that had shown recurring bouts of chronic diarrhoea and weight loss over a 5-month period. A heavy burden of helminths, mainly cyathostomes (trichonemes) was present at post-mortem examination and no significant bacterial pathogens were recovered. It was considered that the Polymorphella (which is normally a commensal organism) had in this case assumed a secondary pathogenic role.

Globule leucocytes and Peyer's patches in lambs infected with coccidia.

In a study of intestinal tissues from worm-free lambs experimentally infected with coccidia, the population of globule leucocytes was on average nine times higher in the mucosa overlying Peyer's patches than in the adjacent mucosa. Mucosal mast cell populations in the two areas were not significantly different. There was evidence of increased migration of globule leucocytes into the villus epithelium in response to coccidial infection.

Demonstration of antibodies to Eimeria species in lambs by an enzyme-linked immunosorbent assay.

Soluble extracts were prepared from sporulated oocysts, unsporulated oocysts and merozoites of Eimeria crandallis, E faurei and E ovinoidalis. They were assessed for antigenicity and specificity by ELISA using rabbit antisera to sporulated oocysts or merozoites. Antibody levels were examined in sera from colostrum-deprived coccidia-free lambs, conventionally reared lambs and lambs which had received experimental infections. Maternal antibody was demonstrated in colostrum and in serum taken at 24 hours from all conventionally reared animals but not colostrum-deprived animals. Antibody levels in conventional animals dropped over the first five weeks of life and rose again during the next five weeks. Antibody was not detected in coccidia-free animals. Monospecific infections of E faurei or E ovinoidalis demonstrated antibody responses to primary and secondary infections. Some specificity of response was suggested with E faurei infection. The antigen preparations showed considerable cross-reactions between species. These serum antibody responses, although appearing too late for individual diagnosis, may assist diagnosis on a flock basis.

The use of skin from a monozygotic twin combined with cultured epithelial autografts as coverage for a large surface area burn: a case report and review of the literature.

Definitive closure of a large burn may be a formidable task requiring a variety of techniques for success. This case report illustrates use of skin from a monozygotic twin to accomplish this goal. A 35-year-old woman ignited herself with gasoline after a domestic quarrel, which produced a burn involving 65% of her body surface area, predominantly full thickness in depth and associated with inhalation injury. After resuscitation, the patient underwent multiple burn excision procedures that used allograft coverage. Histocompatibility testing confirmed that use of her twin sister's skin was a viable strategy for burn wound closure, and ultimately, with use of this technique, the patient's anterior torso was covered. Her abdomen and anterior thighs were covered with cultured epithelial autografts, and her face and arms were autografted with the patient's donor sites. She was discharged on the one hundred sixth postburn day to a rehabilitation center. This is the fourteenth reported case of burn wound grafting with use of skin from an identical twin, and the first in which it was combined with cultured epithelial autografts. There were no adverse consequences of this procedure either for the patient or her donor twin.

Ovine coccidiosis: heavy infection in young lambs increases resistance without causing disease.

Seven groups of twin lambs, kept with their dams on pasture, were given single oral inoculations of 10,000 oocysts of Eimeria ovinoidalis and 10,000 E crandallis at one, two, four, seven, 14, 21 or 28 days after birth, respectively. All were then challenged with 100,000 of each species at 42 days of age. An eighth group was challenged without having received the earlier 'immunising' inoculum, and a ninth group was not inoculated at all. Bodyweights, faecal consistency, oocyst output, and serum coccidial antibody levels were monitored up to 12 weeks of age. No clinical response was detected to inoculation up to four days of age. Loosening of faeces and a slight setback in weight-gain occurred in lambs inoculated seven, 14 and 21 days after birth; inoculation 28 days after birth caused severe diarrhoea and weight loss. Challenge at 42 days caused severe coccidiosis with 50 per cent mortality in the 'unimmunised' group. In those that had received 'immunising' inoculations, the challenge at 42 days caused some diarrhoea and some weight loss, but much less than in the 'unimmunised' lambs. The later the 'immunisation', the less severe was the disease attributable to the challenge at 42 days. Serum antibody levels correlated fairly closely with resistance to the disease. It was concluded that very young lambs were resistant to the pathogenic effects of some coccidia, but were able to respond to them immunologically.

Immunisation of lambs against coccidiosis.

Two groups of twin lambs, kept with their dams at pasture, were given 10,000 oocysts of Eimeria crandallis and 10,000 oocysts of E ovinoidalis either at birth only, or on four occasions at weekly intervals. A further group received 1000 oocysts of each species three times a week in a 'trickle infection' from birth to 21 days of age. All these lambs, together with a susceptible control group were challenged with 100,000 oocysts of each species at 28 days of age. A fifth group received no inoculations throughout. Bodyweight, faecal consistency and oocyst output were monitored up to nine weeks of age. There was no clinical response to any of the immunising inoculations and no change in the faecal consistency, but the group infected at birth grew significantly faster than the uninfected controls. The pattern of oocyst output showed that only E crandallis developed fully in the newborn animal, but both species multiplied in seven-day-old lambs. The challenge infection produced 80 per cent mortality in the susceptible control group and 20 per cent mortality in the group which had received only one immunising dose at birth. The other immunised groups were well protected and gained more weight than the unchallenged controls. At nine weeks of age, the weight gain of the lambs which had received the 'trickle infection' was significantly higher than that of all the other groups.

Medication against ovine coccidiosis--a review.

Data published since 1940 on the use of drugs to prevent or treat ovine coccidiosis are presented in the form of tables. These highlight the differences in conditions of husbandry and mode of administration. Such differences partly account for the variability of response to medication. Drugs that have proved useful under certain conditions include amprolium, monensin and lasalocid for prevention, and sulphonamides for treatment.

Ovine coccidiosis: studies on the pathogenicity of Eimeria ovinoidalis and E. crandallis in conventionally-reared lambs, including possible effects of passive immunity.

No pathogenic effect was detected in lambs when 10(4) oocyts of each species were inoculated before 72 h of age. At 4 weeks of age the combined inoculum caused diarrhoea and weight loss, the severity being roughly proportional to the size of the inoculum. Even 1000 oocysts of each species caused diarrhoea; the pathogenic effect was attributable mainly to E. ovinoidalis. Hyperimmunization of ewes during pregnancy (by repeated inoculation of massive doses of oocysts) reduced the effects of oocyst inoculation in their progeny. Levamisole administration during pregnancy increased the birthweight of lambs.