Cryptosporidiosis of man and calf: a case report and results of experimental infections in mice and rats.

Cryptosporidiosis is reported in a healthy 25-year-old male. Clinical symptoms include 1 day of nausea and low-grade fever and 9 days of diarrhea, followed by 3 days of constipation. Oocysts of Cryptosporidium sp. were present in sugar flotations of the first fecal sample collected 56 hours after onset of the symptoms and in daily fecal samples collected through day 12 of the illness. Oocysts of the human isolate of Cryptosporidium sp. were morphologically indistinguishable from those obtained from naturally and experimentally infected calves. After 1 week of sporulation at room temperature, oocysts from the human and from calves contained four sporozoites and a spherical residuum. When inoculated orally, sporulated Cryptosporidium sp. oocysts of human and of calf origin produced indistinguishable infections in suckling mice and rats and in adult mice.

Coccidia in cows and calves on pasture in north Georgia (U.S.A.).

The prevalence and abundance of coccidian oocysts were determined in a herd of beef cows and calves on fescue pastures in the Piedmont area of Georgia during 4-consecutive grazing seasons. Twelve species of Eimeria were found in the feces of the calves and 10 species were found in the feces of the cows. Eimeria bovis was the most prevalent species found in both the calves and cows. It occurred in 72.5% of 1090 samples from the calves and 10.2% of 719 samples from cows. Eimeria bovis also comprised the majority of oocysts present in the fecal samples from the calves and cows. The greatest number of E. bovis in a sample was 45 800 oocysts per gram of feces (OPG) from a calf and 1900 OPG from a cow. No cases of clinical coccidiosis were seen in any of the animals sampled during the survey.

Quantitative determination of coccidian oocysts in beef calves from the coastal plain area of Georgia (U.S.A.).

For two consecutive years, determinations were made of the prevalence and abundance of coccidian oocysts from crossbred beef calves raised on Bahia grass pastures in the coastal plain area of Georgia. Of the 534 fecal samples collected during the survey, 461 (86.3%) contained one or more species of coccidian oocysts. The total mean oocysts per gram of feces (OPG) was significantly different (P less than 0.10) between the two years. Thirteen species of Eimeria were found during both years of the survey. Eimeria bovis was the most prevalent species found in the survey; E. ellipsoidalis, however, had the greatest number of OPG. Eimeria bukidnonensis, E. pellita, and E. brasiliensis were the least prevalent species and also had the lowest numbers of OPG. Only one clinical case of coccidiosis was seen. A nine-month-old calf had E. zuernii coccidiosis; it excreted E. zuernii oocysts in several fecal samples before the clinical disease appeared.

The sporulation time of Isospora suis oocysts from different sources.

Feces containing Isospora suis oocysts were collected from naturally- and experimentally-infected pigs from four different areas of the United States. The unsporulated oocysts were cleaned, concentrated, mixed with 2.5% aqueous potassium dichromate solution, poured into petri dishes to a depth of 5 mm, and incubated at 25 degrees C. The oocysts were examined with a microscope at 12 h intervals and the stages of sporulation present were counted. Although a few oocysts were completely sporulated after 12 h of incubation, in most fecal samples the majority of the oocysts were not completely sporulated until 24 or 36 h. In the present study, the sporulation time of I. suis oocysts was considered to be less than or equal to 48 h. There were no major differences in the sporulation times of I. suis oocysts from the different sources.

Attempts to produce experimental Eimeria wyomingensis infections in calves.

Attempts were made to produce repeatable infections with Eimeria wyomingensis in 2- to 4-wk-old calves. From 0.2 million to 10 million sporulated oocysts, or sporocysts from 1 million sporulated oocysts were given orally to 50 calves. Several regimens of flumethasone and dexamethasone at excessive dosage levels were given to some to the oocyst-inoculated calves. Nine of 10 calves given flumethasone and one of 12 calves given dexamethasone treatments died. Of the 41 calves which survived past post-inoculation day 21, 32 had patent infections. The prepatent period in the 32 infections was 13 to 15 (mean 14.2) days and the patent period was 1 to 7 (mean 3.6) days. More fecal oocysts were excreted by calves given sporulated oocysts than those given sporocysts. Calves given corticosteroids passed fewer oocysts than nontreated calves.

The endogenous stages of Eimeria utahensis (Protozoa: Eimeriidae) in the kangaroo rat, Dipodomys ordii.

The endogenous life cycle of Eimeria utahensis is described from experimentally infected kangaroo rats, Dipodomys ordii. The endogenous asexual cycle consisted of 4 generations of meronts. First-generation meronts were concentrated in the anterior third of the small intestine. The succeeding generations of meronts and the sexual stages were concentrated in the middle third of the small intestine. First-generation meronts had a mean diameter of 9.7 micrometer and contained 12 to 16 merozoites. Second-generation meronts had a mean diameter of 8.0 micrometer and contained 12 to 16 merozoites and a residual body. Third-generation meronts had a mean diameter of 12.4 micrometer and contained 4 to 8 merozoites. Fourth-generation meronts had a mean diameter of 8.6 micrometer and contained 16 to 24 merozoites. Young gamonts were located in epithelial cells of the crypts of the small intestine. Shortly after the parasites entered the epithelial cells, the infected cells became displaced into the lamina propria, and most of the mature gamonts were in this location. The nuclei of host cells containing young sexual stages became greatly elongated and flattened. A few young gamonts were seen in cells in which the host cell nuclei were dividing. During development, nuclei of microgamonts became arranged on the periphery of numerous compartments. Only one type of wall-forming body could be distinguished in the macrogamonts.

Sporogony of Isospora suis Biester, 1934 of swine.

Sporogony of Isospora suis of swine is described. Unsporulated oocysts were collected immediately after defecation, mixed in 2.5% potassium dichromate solution, incubated at various temperatures, examined at different time intervals, and classified as to stage of development. The uninucleate sporont underwent nuclear division and became binucleated, and then divided to form two round, uninucleate sporoblasts. Binucleate sporoblasts elongated to form binucleate sporocysts, each of which then gave rise to four sporozoites. Sporulation was completed within 56 hr at 20 C, 40 hr at 25 C, 16 hr at 30 C, and 12 hr at 37 C. No sporulation occurred at 4, 40, 42, 45, or 50 C. The thermal death point was between 37 and 40 C.

Endogenous stages of Eimeria tuskegeensis (Protozoa: Eimeriidae) in the cotton rat, Sigmodon hispidus.

Endogenous stages of Eimeria tuskegeensis were studied in experimentally infected cotton rats, Sigmodon hispidus. Almost all parasites were located on the basilar side of the nucleus in epithelial cells on the sides and tips of villi of the small intestine. The endogenous cycle consisted of three generations of schizogony followed by gametogony. First-, second-, third-generation schizonts could be distinguished by time of appearance, size and shape of the schizont, and number, size, shape, and arrangement of merozoites. Immature gametogonous stages appeared to 84 hr postinoculation (PI) and developed into mature microgametocytes and macrogametes by 96 hr PI. Microgametocytes had a mono-centric type of development. Intermediate macrogametes had small, basophilic wall-forming bodies and mature macrogametes had large, eosinophilic wall-forming bodies. It was not possible to determine whether these were two distinct types of wall-forming bodies or whether they were different stages of a single type. Two nuclei were seen in the host's epithelial cells parasitized by schizonts, microgematocytes, macrogametes, and oocysts. This binucleate condition was apparently parasite-induced.

Redescription of oocysts of the bovine coccidia Eimeria bukidnonensis Tubangui 1931 and E. wyomingensis Huizinga and Winger 1942.

Oocysts of Eimeria bukidnonenisis and E. wyomingensis were found to be morphologically similar, and could be reliably differentiated only by measurements. Pyriform oocysts of E. bukidnonensis measured 43 to 51 by 30 to 35 mum (mean 47.4 by 33.0 mum); sporocysts were 18 to 21 by 9 to 11 mum (mean 19.6 by 9.8 mum). Micropyle present; polar granule, oocyst residuum, and sporocyst residuum absent. Oocyst wall of 2 layers, 3.5 mum thick, and dark brown. Pyriform oocysts of E. wyomingensis measured 36 to 44 by 26 to 30 mum (mean 39.9 by 28.3 mum); sporocysts were 17 to 20 by 8 to 10 mum (mean 18.7 by 8.6 mum). Micropyle present; polar granule, oocyst residuum, and sporocyst residuum absent. Oocyst wall of 2 layers, 2.5 mum thick, and colored brown. The width of the oocyst was the most reliable criterion for differentiating the 2 species.

The sexual stages of Eimeria wyomingensis Huizinga and Winger, 1942, in experimentally infected calves.

Seven of 12 calves given 10(6) Eimeria wyomingensis sporulated oocysts had sexual stages of the parasite when examined at necropsy. Clinical signs of coccidiosis were not observed in any calf. Sexual stages were located in host cells in the lamina propria of the villi in the terminal small intestine. Infected host cells underwent nuclear and cytoplasmic hypertrophy. Immature microgamonts usually had folded cytoplasm and an overall spherical to elongate shape. Mean length and width +/- SEM of immature microgamonts were 43.3 +/- 1.6 by 29.0 +/- 1.1 micron. Mature microgamonts contained hundreds of microgametes, lacked visible cytoplasmic folds, and measured 52.8 +/- 4.7 by 43.0 +/- 4.2 micron. Macrogamonts were spherical to ovoid and had a large nucleus and prominent nucleolus. Immature macrogamonts without visible wall-forming bodies measured 16.0 +/- 0.5 by 13.3 +/- 0.2 micron. Mature macrogamonts had 3-8-micron eosinophilic wall-forming bodies and measured 24.6 +/- 0.7 by 19.6 +/- 0.8 micron. Oocysts were ovoid and had a 2-3-micron-thick eosinophilic oocyst wall. A micropyle was present in appropriately sectioned oocysts. Oocysts measured 27.7 +/- 1.7 by 19.3 +/- 0.8 micron. The sexual stages of E. wyomingensis are compared to those described previously for species of Eimeria infecting the bovine small and large intestines.

Endogenous development of the swine coccidium, Isospora suis Biester 1934.

The endogenous development of Isospora suis Biester 1934 is described in piglets inoculated with 150,000 or 200,000 sporulated oocysts. Endogenous stages developed within villous epithelial cells throughout the small intestine. Two distinct types of meronts were seen in tissue sections. Type I meronts, which were seen at 3 days postinoculation, were binucleate, elongate, and 10.5 by 4.7 micron. They produced two to 14 Type I merozoites per parasitophorous vacuole. Type I merozoites were 10.0 by 3.6 micron. They produced two to 14 Type I merozoites per parasitophorous vacuole. Type I merozoites were 10.0 by 3.6 micron. Type II meronts, which were seen at 4 days postinoculation, were elongate and contained three to 12 nuclei. Type II meronts were 11.4 by 5.3 micron, and one to four were found per parasitophorous vacuole. Type II merozoites were 6.3 by 2.1 micron, and three to 16 were found per parasitophorous vacuole. The peak of asexual development occurred 4 days postinoculation. Fully developed microgamonts, macrogamonts, and oocysts were seen 5 days postinoculation. The prepatent period was 5 days, and the patent period was 5 to 8 days. No extraintestinal stages were seen.

Coccidia of sandhill cranes, Grus canadensis.

Eimeria gruis Yakinoff and Matschoulsky 1935, Eimeria reichenowi Yakimoff and Matschoulsky 1935, and an Adelina species are described from sandhill cranes in the United States. E. gruis was found in the feces of 11 of 14 Florida sandhill cranes (Grus canadensis pratensis) and 62 of 72 greater sandhill cranes (G. c. tabida) from Florida, 5 of 14 greater sandhill cranes from Arizona, and 4 of 16 lesser sandhill cranes (G. c. canadensis) from Texas. E. reichenowi was found in the feces of 12 of 14 Florida sandhill cranes and 66 of 72 greater sandhill cranes from Florida, 4 of 14 greater sandhill cranes from Arizona, and 5 of 16 lesser sandhill cranes from Texas. Adelina sp. was found in the feces of 3 of 14 Florida sandhill cranes and 2 of 72 greater sandhill cranes from Florida. The Adelina species is considered to be a spurious parasite of the cranes.

Anthelmintic efficacy of 22,23-dihydroavermectin B1 against gastrointestinal nematodes in calves.

Anthelmintic activities of 22,23-dihydroavermectin B1 (comprised to greater than or equal to 95% 22,23-dihydroavermectin B1a and less than or equal to 5% 22,23-dihydroavermectin B1b) against gastrointestinal nematodes in calves were evaluated in 2 controlled experiments. Infective larvae of Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, and C punctate were given to 11-week-old calves and Oesophagostomum radiatum had been given 21 days earlier to allow all larvae to attain adulthood at the same time. Each experiment had 4 groups of 5 calves each. Treatment was given to the calves at 14 weeks of age, and 7 to 8 days after treatment, the calves were necropsied. In experiment 1, group 1 control calves had a geometric mean of 11,054 nematodes; groups 2, 3, and 4 calves (at 14 weeks of age) given 22,23-dihydroavermectin B1 orally at doses of 50, 100, or 200 microgram/kg had reductions of 73.5%, 97.3%, and 99.7%, respectively. In experiment 2, group 5 control calves had a geometric mean of 18,897 nematodes; groups 6, 7, and 8 calves given 22,23-dihydroavermectin B1 subcutaneously at doses of 50, 100, or 200 microgram/kg had reductions of 74.6%, 95.3%, and 98.8%, respectively.

Anthelmintic efficacy of ivermectin against immature gastrointestinal pulmonary nematodes of calves.

Anthelmintic efficacy of ivermectin (greater than or equal to 80% 22,23-dihydroavermectin B1a and less than or equal to 20% 22,23-dihydroavermectin B1b) was evaluated in a controlled experiment against immature nematodes. Twenty calves raised to about 8 weeks of age under nematode-free conditions were allocated into 4 groups. Infective larvae of Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, C punctata, Oesophagostomum radiatum, and Dictyocaulus viviparus were given orally to each calf on a staggered schedule 6 to 14 days before treatments. The drug was given subcutaneously when the nematodes were in the early 4th stage of development, and the calves were killed 23 or 24 days later. Group 1 nonmedicated control calves had a geometric mean of 25,102 nematodes; groups 2, 3, and 4 calves given ivermectin at dose rates of 50, 100, or 200 micrograms/kg had reductions of 88.2%, 98.0%, and 99.8%, respectively.

Anthelmintic activities of B1a fraction of avermectin against gastrointestinal nematodes in calves.

Anthelmintic activities of the B1a fraction of avermectin were evaluated in a controlled experiment. Twenty 12-week-old calves artificially infected with gastrointestinal nematodes were allotted to four groups. Calves in group 1 were used as nonmedicated controls; other calves in groups 2, 3, and 4 were given (orally) B1a avermectin at dosage levels of 50, 100, and 200 microgram/kg of body weight, respectively. These treatments were given 35 days after calves were inoculated with infective nematode larvae. In groups 2, 3, and 4, overall reductions (based on geometric means) were 98.6%, 98.7%, and 98.4%, respectively. These reductions were highly significantly different (P less than 0.01) from the control calves. Nematodes in the calves were Haemonchus contortus. Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, C punctata, and Oesophagostomum radiatum.

Efficacy of salinomycin in treatment of experimental Eimeria bovis infections in calves.

The efficacy of salinomycin for treatment of experimental Eimeria bovis infections was evaluated. In experiment 1, 18 calves were placed into four groups. Group 1 calves were nonmedicated controls; groups 2, 3, and 4 calves were given salinomycin (0.33, 0.66, and 1.00 mg/kg of body weight, respectively) in daily oral divided doses starting 2 or 3 days prior to E bovis inoculations and continuing until postinoculation day (PID) 21. Calves treated with 0.66 and 1.00 mg/kg (groups 3 and 4) passed substantially fewer oocysts than did control calves (group 1) or calves treated with 0.33 mg/kg (group 2). Group 1 control calves had typical signs of severe E bovis infections, whereas signs of infection in medicated calves were almost nonexistant. Experiment 2 was conducted as before, with 15 calves. Group 5 calves were nonmedicated controls; groups 6, 7, and 8 calves were treated with 0.5, 1.0, and 2.0 mg/kg, respectively. All group 8 calves and three of four group 7 calves had nearly complete suppression of oocyst excretions. The severity of the disease in the group 5 control calves was not as extensive as it was in group 1 control calves. In experiment 3, 16 calves were used. Group 9 calves were nonmedicated controls, whereas other calves were given salinomycin (2.0 mg/kg) during PID 3 to 7 (group 10), PID 8 to 12 (group 11), and PID 13 to 17 (group 12). Salinomycin therapy in group 2 calves resulted in substantial reductions in oocyst excretions and clinical signs.

Anthelmintic activity of fenbendazole against gastrointestinal nematodes in calves.

Anthelmintic activities of fenbendazole were evaluated in a controlled experiment. Forty calves artificially infected with gastrointestinal nematodes were allotted to 4 groups. Calves in group 1 were used as nonmedicated controls; the other calves were given (orally) fenbendazole at the dose level of 5 mg/kg in the forms of a suspension (group 2), medicated feed to individual calves (group 3), and medicated feed to the group (group 4). These treatments were given on day 35 after calves were inoculated with infective nematode larvae. In groups 2, 3, and 4, overall reductions (based on geometric means) were 99.5%, 99.7%, and 99.6%, respectively. These reductions were highly significantly different (P less than 0.01) from the control calves. Nematodes present in the calves were Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia onchophora, C punctata, and Oesophagostomum radiatum.

Anthelmintic efficacy of albendazole against adult Dictyocaulus viviparus in experimentally infected calves.

Anthelmintic activity of albendazole against adult Dictyocaulus viviparus was evaluated in a controlled experiment. Calves were raised nematode-free to approximately 8 weeks of age and were each given 4,000 infective 3rd-stage larvae. Twenty calves with patent parasitisms were allotted to 2 groups of 10 calves each. Calves in group 1 were used as nonmedicated controls, and calves in group 2 were given albendazole in paste formulation at the dosage concentration of 7.5 mg/kg of body weight on the 30th day after administration of infective larvae. At necropsy, nonmedicated control calves had a total of 308 adult D viviparus, whereas the albendazole-treated calves had 11, for an average efficacy of 96.4%. These reductions were statistically highly significant (P less than 0.01). At necropsy, none of the treated calves was passing 1st-stage C viviparus larvae in their feces, whereas control calves were passing an average of 46 larvae/10 g of feces.

Anthelmintic activity of albendazole against gastrointestinal nematodes in calves.

Anthelmintic activities of albendazole were evaluated in a controlled experiment. Forty calves experimentally infected with gastrointestinal nematodes were allotted to 4 groups. Calves in group 1 were used as nonmedicated controls; calves in groups 2, 3, and 4 were given (by oral route) a suspension containing albendazole at dose concentrations of 2.5, 5.0, and 7.5 mg/kg of body weight on the 35th day after administration of infective nematode larvae. In groups 2, 3, and 4 calves, average overall reductions (based on geometric means) were 77.1, 93.6, and 98.1%, respectively. These reductions were highly significant (P less than 0.01) in calves given doses of 5.0 and 7.5 mg/kg, and were significant (P less than 0.05) in calves given the 2.5-mg/kg dose. Ostertagia ostertagi, Trichostrongylus axei, Cooperia onchophora, Cooperia punctata, and Oesophagostomum radiatum removals at the 5.0- and 7.5-mg/kg dose levels were all highly significant (P less than 0.01); whereas, removals of Haemonchus contortus were not significant, even at the 7.5-mg/kg dose level.

Alkaline phosphatase activities in intestinal mucosa from calves infected with Cooperia punctata and Eimeria bovis.

Thirty calves 12 weeks of age raised under essentially parasite-free conditions were used to determine the effects of Cooperia punctata and Eimeria bovis (in single and combination infections) on mucosal alkaline phosphatase activities at 8 locations in the small intestine. In experiment 1, 5 calves infected with C punctata 3 weeks previously had highly significant (P less than 0.01) reductions in mucosal alkaline phosphatase activities compared with those in 5 noninfected control calves. These reductions were greatest in the 2 locations of the intestine closest to the pylorus. Infected calves had a mean of 44,356 C punctata adults present. In experiment 2, 5 calves infected with E bovis 2 weeks previously had significant (P less than 0.05) reductions in mucosal alkaline phosphatase activities compared with those in 5 noninfected control calves. These reductions were present in the caudal half of the intestine. Numerous 1st-generation E bovis schizonts were present in the caudal third of the intestine. In experiment 3, 5 calves infected with C punctata and E bovis of the same durations as in experiments 1 and 2 had highly significant (P less than 0.01) reductions in mucosal alkaline phosphatase activities in the cranial half of the intestine compared with those in the controls. These reductions were much larger than in either of the monospecific infections (experiments 1 and 2). A mean of 31,968 adult C punctata were recovered from the infected calves, and numerous E bovis schizonts were observed in the caudal third of the intestine.