Fatal Intestinal Coccidiosis in a Three-Week-Old Buffalo Calf (Bubalus bubalus)
Abstract The water buffalo (Bubalus bubalus) is important to the economy of several countries, especially in Asia and South America. Little is known regarding the impact of coccidiosis in buffaloes. Cattle and buffaloes are considered to have common species of Eimeria, but critical cross-transmissions have not been made because it is difficult to raise these hosts coccidian free. Clinical coccidiosis was confirmed post mortem in a 22-day-old buffalo calf that died after a 3- to 4-day illness. Oocysts morphologically identical to Eimeria bareillyi were found in the feces and in sections of small intestine. Oocysts were often pyriform, sometimes with asymmetrical sides. The shorter end was flattened and approximately 5–6 μm wide. Unsporulated oocysts in feces were 23.2–29.5 × 16.5–22 μm, with an average of 27.2 × 19.3 μm. Schizonts, gamonts, and oocysts were identified in sections of small intestine where they were located in enterocytes of the jejunum and ileum. No coccidian stages were seen in sections of colon. This is one of the first confirmed cases of clinical coccidiosis in water buffalo.
The occurrence of a second asexual generation in the life cycle of Eimeria bovis in calves.
To determine whether Eimeria bovis has a second asexual generation occurring in the large intestine of calves, three biopsy experiments were conducted. In each, 0.5 to 1.0 billion E. bovis merozoites were introduced into the ligated cecum of a young calf. The merozoites were in mucosal scrapings obtained from the small intestine of a calf killed 15 days after inoculation with 2.0 million oocysts, 95% E. bovis. During the 6 to 72 hr after the inoculation of merozoites, three or four cecal biopsies were made in each calf. One calf was killed 80 hr after inoculation. The other two discharged only E. bovis oocysts on the 5th and 6th and 5th to 7th day after inoculation, respectively. In the histological sections of the cecum of each calf, many immature schizonts were found in the tissues taken at 6 to 36 hr, numerous mature schizonts were seen at 42 to 48 hr, many very early gametocytes at 48 hr, and progressively more advanced gametocytes at 60, 72, and 80 hr. Mature schizonts in the sections had a mean size of 8.9 by 10.0 t; they contained 30 to 36 merozoites, averaging 1.2 by 3.5 p. Fresh merozoites were 5.7 to 6.8 /L long, with a mean of 6.2. The findings demonstrate that a second asexual generation is included in the life cycle of E. bovis and occurs in the epithelial cells of the cecum and colon. The life cycle of Eimeria bovis was reported by Hammond, Bowman, Davis, and Simms (1946) to include apparently only a single generation of large schizonts occurring in the small intestine. The sexual stages were found to be located in the glands of the cecum and colon. In recent work on the immunology of E. bovis we frequently found small schizonts in the large intestine of calves inoculated with this species. These schizonts typically occurred in association with the gametocytes of E. bovis. For this reason experiments were conducted to determine whether E. bovis has a second generation of schizonts developing in the cecum and colon. Received for publication 28 January 1963. * Supported in part by research grant E-2374 from the Institute of Allergy and Infectious Diseases and by a fellowship (GPM-18,586) from the Division of General Medical Sciences, Public Health Service. The research was conducted under a cooperative agreement between the Utah Agricultural Experiment Station and the Animal Disease and Parasite Research Division, Agricultural Research Service, U. S. Department of Agriculture. Published as Journal Paper No. 306, Utah Agricultural Experiment Station. MATERIALS AND METHODS Six Holstein-Friesian male calves, 3 to 5 weeks old, were used in a series of three biopsy experiments. Three of the six calves were used as sources of merozoites for inoculation. The methods of housing, feeding, inoculating, and sampling for oocysts were similar to those already described (Hammond, Andersen, and Miner, 1963). In each experiment, by means of a laparotomy performed under local anesthesia, the cecum was ligated and a small piece was removed from the blind end for comparison with sections to be obtained after inoculation. After rinsing out the cecum with physiological saline solution the incision was partially closed. Fifty to 60 ml of mucosal scrapings, containing approximately 0.5 to 1.0 billion E. bovis merozoites, were then introduced by syringe, and the suturing of the incision was completed. The mucosal scrapings were obtained from the "source" calves, which were killed 15 days after inoculation with 2.0 million oocysts, 95% E. bovis, 3% E. auburnensis, 1% E. ellipsoidalis, and less than 1% E. cylindrica. The scrapings were collected in saline or Ringer's, concentrated by sedimentation and centrifugation, and homogenized for about 30 sec in a blender to free the merozoites from the schizonts. The interval between the killing of one calf and the introduction of the merozoites into the cecum of another was 3 to 5 hr. The incision in the flank in two of the calves was closed with a temporary suture, through and through, using umbilical tape. In the third calf a row of loops of umbilical tape was placed along 428 This content downloaded from 207.46.13.184 on Sun, 10 Apr 2016 04:38:11 UTC All use subject to http://about.jstor.org/terms HAMMOND ET AL.-LIFE CYCLE OF EIMERIA 429 TABLE I. Results of biopsies in three calves given cecal inoculations with merozoites of E. bovis. Dimensions ( microns) Hr after No. of Chief stages found inoc. biopsies Mean Range 6 1 Schizonts, 1 nucleus 2.0 X 2.0 (3)1 1.8 X 1.8 to 2.2 X 2.2 12 2 Schizonts, 1 nucleus 2.7 X 3.3 (15) 1.3 X 1.9 to 3.8 X 3.8 24 2 Schizonts, 1 to 8 nuclei (mean 4.7) 4.9 X 5.7 (50) 2.9 X 2.9 to 7.2 X 8.6 36 1 Schizonts, 8 nuclei to mature 6.7 X 7.9 (18) 5.7 X 5.7 to 7.2 X 14.3 (mean 15.0) 42 1 Schizonts, 8 nuclei to mature 8.3 X 9.0 (40) 5.7 X 7.2 to 10.0 X 11.4 (mean 19.5) 48 2 Mature schizonts 8.9 X 10.0 (100) 7.2 X 7.2 to 11.4 X 11.4 Very early gametocytes 2.3 X 2.5 (100) 1.3 X 1.9 to 3.2 X 3.2 60 1 Early intermediate gamnetocytes 3.3 X 3.6 (100) 2.6 X 2.6 to 4.5 X 4.5 72 1 Intermediate gametocytes 7.0 X 7.3 (100) 5.1 x 5.1 to 9.6 X 11.5 802 1 Late intermediate gametocytes 11.0 X 12.5 (100) 9.0 X 9.0 to 12.8 X 19.2 1 Number of specimens. 2 Tissues obtained at necropsy instead of biopsy. each side of the incision, and the wound closed by lacing between the loops. Three or four additional cecal biopsies were performed in each of the three experiments at intervals of (no. 1) 6, 12, 24, and 48 hr; (no. 2) 24, 48, and 72 hr; and (no. 3) 12, 36, 42, and 60 hr. The cecal ligature was removed at 24 or 36 hr. The first calf was killed 80 hr after the operation. The other two were allowed to survive so that the discharge of oocysts could be determined; the incision in the flank was permanently closed after the last biopsy in these two calves. At each biopsy a small piece of cecum was removed and bisected; one portion was fixed in Serra's and the other in Helly's or Zenker's. The former tissue was stained with periodic-acid-Schiff and with Hime's and Moriber's methods, the latter with iron hematoxylin and hematoxylin-eosin. Measurements of stained coccidial stages were made with the iron hematoxylin preparations. Observations were also made on mucosal scrapings from fresh cecal tissue.
Silica in Soils1
Publisher Summary Silica in free and combined forms is a dominant component of the solid material of many soils, and dissolved silica is commonly a major solute of soil solutions. Breakdown of primary silicates, translocation of silica in solution, and deposition of secondary silica-containing substances are involved in the development of soils. Ions essential for the growth of plants are released to the soil solution as silicates weather, and these ions may be held against leaching at exchange sites on other silicates. Silica is absorbed in appreciable quantities by some plants and is returned to the surface of the soil as the plants decay. The nature and transformations of silica and silicates in soil are, thus, fundamental to an understanding of many aspects of soil and plant sciences.