Effects of different inoculation routes on the parasitic sites of Cryptosporidium baileyi infection in chickens

Cryptosporidiosis is prevalent in domesticated, caged, and wild birds. Cryptosporidium baileyi, an ascendant species of avian Cryptosporidium, is an important pathogen. It causes respiratory disease in chickens, especially chickens younger than 50 days. In this study, SEM, histological, semi-quantitative PCR, and nested PCR techniques were used to explore the impact of different inoculation routes on sites of C. baileyi infection in chickens. Results showed that inoculation with sporozoites or oocysts via the rectum was an effective means of causing infection. This may provide an important reference for the development of the transfection system of C. baileyi in chickens. Numerous endogenous stages of C. baileyi were observed in the bursas of Fabricius (BF) and cloacas of chickens inoculated with sporozoites or oocysts via the rectum, but no parasite was seen in the tracheas of any of these chickens. In chickens infected with oocysts via the crop, the number of parasites in the BF was approximately 23-fold more than in the trachea. All blood samples collected after inoculation were negative for C. baileyi. These data show that C. baileyi was not transferred by blood circulation between the BF and respiratory tract. Different routes of inoculation were here found to distinctly affect sites of parasitism in chickens. These findings may facilitate further understanding of the biology of C. baileyi and efforts to control avian cryptosporidiosis.

Cryptosporidium baileyi--infection in Red-breasted Merganser (Mergus serrator) ducklings from a zoological garden

Infection of the Bursa of Fabricius with Cryptosporidium baileyi was diagnosed in a group of hand reared Red-breasted Merganser (Mergus serrator) ducklings during one breeding season in a German zoological garden.The birds had died in an emaciated and anaemic state after problems with spontaneous feeding. The bursae were infected with moderate to high numbers of cryptosporidia, which were associated with hyperplasia, degeneration and sloughing of the affected epithelial cells and mild heterophilic bursitis, lesions typically seen in bursal cryptosporidiosis in other avian species. In addition, lymphatic tissue was nearly absent, which was probably caused by chronic stress and malnutrition related to the rearing of these highly stress-sensitive birds in an artificial environment. Companion ducklings from stress-resistant, spontaneously feeding species from the zoological collection were used to calm the Mergansers, but may have introduced the cryptosporidia into the rearing boxes. Another possible source for the introduction of C. baileyi were adult mallards (Anas platyrhynchos), which were used to increase the hatching rate by a phase of natural breeding in the middle third of the incubation period of the Merganser eggs.

[Morpho-functional changes of cloacal bursa of the herring gull in experimental infection with gull tapeworm]

Using the methods of light microscopy, the quantitative changes in the cells of the cloacal bursa of herring gull (Larus argentatus mongolicus) chicks were studied during experimental infection with gull-tapeworm Diphyllobothrium dendriticum. The area of the follicles within the bursa and the number of eosinophils in the infected chicks were found to increase. In the follicles the number of blast cells and large lymphocytes was elevated. The reduction of small lymphocytes and plasma cells numbers in the infected gulls may be due to a slower cell cycle or cell migration into the inflammatory focus. Overall, the changes in the bursa indicate the suppression of the B-link of the host immune system in tapeworm invasion.

[The reaction of the bursa and thymus eosinophils in the herring gull after the experimental infection with gull-tapeworm]

Using the methods of light microscopy, eosinophil topography, quantitative and qualitative changes (degranulation level of and a cationic protein content) were studied in the thymus and bursa of 36 herring gull nestlings Larus argentatus mongolicus (Suskin, 1925) 2 weeks after experimental infestation with gull-tapeworm Diphyllobothrium dendriticum (Nitsch, 1824). Eosinophils in the thymus were located in trabecules, mainly close to the blood vessels, thymic (Hassall's) corpuscles and also directly inside them, while in the bursa they were found within the internodular space. As compared with the control bird counts, relative eosinophil count in the birds with an average invasion intensity was increased 3.8 times in the thymus and 2.5 times in the bursa. In birds with high invasion intensity, these counts were increased 4 times in the thymus and 1.2 times in the bursa.

Experimental study on respiratory cryptosprodiosis

Cryptosporidiosis has a worldwide geographical and zoological distribution. Cryptosporidium baileyi oocysts were isolated from the bursa of Fabricius (BF) of 4 weeks-old of 100 broilers. Twenty five broiler chicks of 2 day old free from cryptosporidial infection were inoculated intratracheally at a dose of 1 x 10(6) chicks. Five chicks were sacrificed at 4th, 8th, 12th, 16th, and 20th day postinoculation. Selected tissues from bursa of Fabricius, cloaca, colon, caeci and tracheas were taken and examined directly by scraping technique for endogenous stages. The distribution of C. baileyi in different tissues in the case of intratracheal inoculation; trachea 23 (92 %) chicks infected, bursa of Fabricius 21 (84%) chicks, Cloaca 5 (16 %) chicks, Colon 1 (4%) chick and the caeci showing no infection. Daily examination of the intratracheal droppings inoculation was done at the 5th day and lasted for 18-20 days, the patent period.

Experimental coccidiosis provoked by Eimeria acervulina in chicks simultaneously fed on ochratoxin A contaminated diet

The progression of coccidiosis provoked by Eimeria acervulina was followed in chicks fed on OTA-contaminated as well as on OTA-free diets. More heavy progress of duodenal coccidiosis, including mortality, occurred in OTA-treated chicks as can be seen from the higher value of lesion (3.50) and oocyst (31.65) indices. A stronger decrease of serum total protein was found in OTA-treated chicks (22.80 g/l) than in chicks infected with E. acervulina(24.20 g/l), but that decrease was strongest in chicks treated with OTA and simultaneously infected with E. acervulina (19.71 g/l). The serum concentration of uric acid was significantly increased in all chicks exposed to OTA, most notably in those additionally infected with E. acervulina (1020.6 (micro mol/L), whereas the serum enzyme activity of AST was increased only in chicks infected with E. acervulina and highest in those fed OTA contaminated diet (122.2 U/L). OTA induced degenerative changes in kidneys, liver and heart as well as a depletion of lymphoid tissue in the lymphoid organs and a decrease of body weight. Coccidiosis induced only a slight growth depression and duodenal hemorrhages in addition to characteristic duodenal damages. The impairment of kidney function, histopathological changes and general growth depression were stronger when chicks infected with E. acervulina were also given OTA.

A recombinant attenuated Salmonella enterica serovar Typhimurium vaccine encoding Eimeria acervulina antigen offers protection against E. acervulina challenge

Coccidiosis is a ubiquitous disease caused by intestinal protozoan parasites belonging to several distinct species of the genus Eimeria. Cell-mediated immunity (CMI) is critically important for protection against Eimeria; thus, our approach utilizes the bacterial type III secretion system (TTSS) to deliver an antigen directly into the cell cytoplasm of the immunized host and into the major histocompatibility complex class I antigen-processing pathway for induction of CMI and antigen-specific cytotoxic T-lymphocyte responses in particular. To accomplish this goal, Eimeria genes encoding the sporozoite antigen EASZ240 and the merozoite antigen EAMZ250 were fused to the Salmonella enterica serovar Typhimurium effector protein gene sptP in the parental pYA3653 vector, yielding pYA3657 and pYA3658, respectively. SptP protein is secreted by the TTSS of Salmonella and translocated into the cytoplasm of immunized host cells. The host strain chromosomal copy of the sptP gene was deleted and replaced by a reporter gene, xylE. The newly constructed vectors pYA3657 and pYA3658 were introduced into host strain chi8879 (DeltaphoP233 DeltasptP1033::xylEDelta asdA16). This strain is an attenuated derivative of the highly virulent strain UK-1. When strain chi8879(pYA3653) as the vector control and strain chi8879 harboring pYA3657 or pYA3658 were used to orally immunize day-of-hatch chicks, colonization of the bursa, spleen, and liver was observed, with peak titers 6 to 9 days postimmunization. In vitro experiments show that the EASZ240 antigen is secreted into the culture supernatant via the TTSS and that it is delivered into the cytoplasm of Int-407 cells by the TTSS. In vivo experiments indicate that both humoral and cell-mediated immune responses are induced in chickens vaccinated with a recombinant attenuated Salmonella serovar Typhimurium vaccine, which leads to significant protection against Eimeria challenge.

Urotocus rossittensis (Trematoda: Digenea: Leucochloriidae) in the scarlet-rumped tanager, Ramphocelus passerinii, and common bush tanager, Chlorospingus ophthalmicus (Passeriformes: Thraupidae), from the Area de Conservación Guanacaste, Costa Rica, with taxonomic revision of the genus and revised key to the leuchochloridiid-like Brachylaimoidea

Urotocus rossittensis occurs in the bursa Fabricii of the scarlet-rumped tanager, Ramphocelus passerinii, and the common bush tanager, Chlorospingus ophthalmicus, from the Area de Conservación Guanacaste, Costa Rica. Morphological examination of type material of U. fusiformis and U. kenyensis and Costa Rican specimens suggests that U. fusiformis and U. kenyensis are indistinguishable from U. rossittensis. Confirmed accounts of Urotocus spp. refer to a single adult morphotype whose geographic distribution includes the Palearctic, Africa, Nearctic, and northern Neotropics.

Cryptosporidium infection in domestic geese (Anser anser f. domestica) detected by in-situ hybridization

An in-situ hybridization (ISH) procedure was developed for the detection of Cryptosporidium sp. in paraffin wax-embedded tissues with a digoxigenin-labelled probe targeting the 18S rRNA. This technique was used in addition to traditional methods, such as haematoxylin and eosin staining, periodic acid-Schiff reaction, transmission electron microscopy and the polymerase chain reaction, to examine the bursa of Fabricius (BF), conjunctiva and other tissues from 20 domestic geese aged 16-36 days for the presence of cryptosporidia. Positive signals were found to a moderate or marked extent in both conjunctival samples (89%) and BF samples (88%) but not in other tissues. Sequencing of the PCR amplification product revealed identity with Cryptosporidium baileyi. The infected geese showed no clinical signs and only scanty histological lesions. These results confirm reports showing that young waterfowl are especially vulnerable to cryptosporidium infection and indicate that the BF and conjunctiva are the preferred sites for the presence of the protozoon. ISH proved a good method for detecting and identifying even small numbers of cryptosporidia in tissue sections.

[Distribution of trematodes of the family Prosthogonimidae in river and lake ecological systems in the south of the Western Siberia]

The results of long-term investigations (1994-2003) of an infection rate of trematodes of the family Prosthogonimidae in the first intermediate hosts (snails of the family Bithyniidae) and in the final hosts (birds) from a basin of the Chany Lake (Western Siberia) are discussed. A total of 1824 specimens of Bithynia tentaculata (L., 1758) and 7166 specimens of Opisthorchophorus troscheli (Paasch, 1842) have been collected from eight rivers and two lakes in the south of the Western Siberia. Data of incomplete helminthological dissection of 225 young water-fowl of 18 species were analyzed. Birds were obtained in July, August and September, 1996-2003 from the Chany lake basin. Maritas of the trematode family Prosthogonimidae were revealed in bursa Fabricii (26.12%) of seven bird species of two orders (Anseriformes and Gruiformes): Grey Lag-Goose Anser anser (L.) (Infection rate-28.6% +/- 12.1), Mallard Anas platyrhynchos L. (27.5% +/- 6.2), Shoveler--A. clypeata L. (22.2% +/- 13.9), Pochard Aythya ferina (L.) (51.7% +/- 9.3), Coot Fulica atra L. (28.6% +/- 5.6), Tufted Duck A. fuligula (L.) (1 case), Wigeon A. penelope L. (1 case). Average intensity of invasion is 5.8 marita specimens per infected bird. The maximal number of parasites (37 maritas), and also the highest average intensity of invasion are recorded for the Coot. The 342 maritas of the family Prosthogonimidae belong to three species: Prosthogonimus ovatus (Rud., 1803) (49.7%), P. cuneatus (Rud., 1809) (32.8%) and Schistogonimus rarus (Braun, 1901) (14.6%); these trematode species have been recorded in 35, 12 and 8 bird species, respectively. Grey Lag-Goose, Shoveler, Pochard and Tufted Duck are new host records for P. cuneatus in for Western Siberia. Parthenitae of trematodes (Prosthogonimidae) were revealed from eight populations of bithyniid snails. The infection rate of the trematodes (parthenitae and cercariae) in population of bithyniid snails from lake ecological system varied 6.55-54.4%, and in river ecological systems in was 0.6-4.2 %. The infection rate of trematodes (parthenitae and cercariae) of the first intermediate hosts was 2.64% that is significantly lower than that of the final hosts from the Chany Lake basin. Both O. troscheli and B. tentaculata were noted as the first intermediate hosts of prosthogonimid trematodes of three species: P. ovatus, P. cuneatus and S. rarus. All three species of trematode were found in three water reservoirs: Ob River (B. tentaculata), Kargat River (O. troscheli) and Chany Lake (O. troscheli). Thus it is found out that 39 bird species can be the final hosts of prosthogonimid trematodes. About a quarter of nestlings is infected with these trematodes. The infection rate of parthenitae in snails from the lake ecosystems is significantly higher than in the river ecosystems.

Histomoniasis in the Bursa of Fabricius of Chickens

Histomoniasis was diagnosed in a flock of 6-wk-old commercial chickens. Clinical signs included depression, stilted gait, inappetence, and a slight increase in mortality. At necropsy, there were pale-yellow to dark-gray circular and depressed necrotic lesions in the liver. The ceca were enlarged and impacted with caseous cores. Cecal worms were not observed either at necropsy or on histopathology. Histomonads were demonstrated microscopically within the bursa of Fabricius in addition to the liver, ceca, and spleen. This is the first report of the presence of histomonads in the bursa of Fabricius in commercial chickens.

Viability of preserved Cryptosporidium baileyi oocysts

The present study was undertaken to determine the viability and infectivity of oocysts of Cryptosporidium baileyi that had been stored from 1 to 40 months at 4 degrees C preserved in 2.5% potassium dichromate solution. Oocysts of C. baileyi were purified from the feces of experimentally infected chickens using discontinuous sucrose gradients. Subsequently, the purified oocysts were suspended in 2.5% potassium dichromate solution at a concentration of 1 x 10(7) organism/ml, and their viabilities were assessed by nucleic acid staining, histologic examination, and infectivity to 2-day-old chickens. All chickens inoculated with oocysts that had been stored for 1-18 months developed patent infections, while chickens infected with older oocysts remained uninfected. Between 5.8% and 82.2% of the oocysts, stored at 4 degrees C in 2.5% potassium dichromate solution, were found to be viable, as determined by nucleic acid staining. Parasite colonization in the bursa of Fabricius was detected in the microvillus border of bursal epithelium. The finding that C. baileyi oocysts remain infective to chickens for at least 18 months offers important time-saving advantages to investigators who frequently require large numbers of oocysts.

Occurrence of intermediate hosts and structure of digenean communities of the black-headed gull, Larus ridibundus (L.)

The factors contributing to the similarity between digenean parasite assemblages parasitizing the black-headed gull were investigated. Thirteen different digenean species from the digestive tract and the bursa of Fabricus were found. We predicted that the structure of parasite communities is not random at either component community or infracommunity levels. We searched for nested patterns in the digenean community, and explored the possible factors contributing to nestedness. We found that digenean species which occupy a narrow range of intermediate hosts are placed out of order in the nested matrix. The influence of several variables related to the water reservoir, geographical distances, and the abundance of intermediate hosts on the species diversity and similarity of parasite communities were tested as well. Because of the complexity in bird digenean life-cycles we supposed that intermediate hosts and ecological characters of their environment could play a major role. We showed that the presence of intermediate hosts is the factor limiting the qualitative and quantitative similarity of parasite communities among different host populations as well as influencing the digenean species diversity in the definitive host. The similarity in abundance of intermediate hosts between different localities was facilitated by the presence of vegetation in water reservoir and more diversified type of water bottom. Digenean species diversity was higher when the water reservoir was exposed to temporal drying. We hypothesized that this factor could facilitate the inclusion of molluscs infected by digeneans in the diet of birds. Both species diversity and dominance were influenced by the bottom type of water reservoir and temporal drying up. Geographical distances between localities influenced the quantitative similarity of digenean communities as well as species richness.

Polyphasic typing of Cryptosporidium baileyi: a suggested model for characterization of cryptosporidia

The present study was undertaken to characterize the oocyst morphology, host specificity, organ location, virulence, and sequences of the small subunit ribosomal RNA, 70-kDa heat shock protein, and oocyst wall protein genes of Cryptosporidium baileyi, and to compare this strain with other Cryptosporidium species. This study also aims to serve as a model for polyphasic (phenetic and genetic) characterization of Cryptosporidium species and strains. On the basis of these results, further genetic and phenetic characterization of an avian isolate is needed if the difference between the length or width, or both, of oocysts of an isolate and of C. baileyi is > or = 10% or if the difference between the oocyst shape index of the isolate and of C. baileyi is > or = 3% (or both). The isolate is infectious for mammals or lower vertebrates, or the host range is narrow, i.e., infectious only for some bird species; after oral or intratracheal inoculation, the parasites are not located in the cloaca and in the bursa of Fabricius or the respiratory tract; clinical disease or weight gain reduction can be observed after oral inoculation; the genetic distance for the examined gene between C. baileyi and the isolate is similar in magnitude to that observed between most closely related Cryptosporidium species.

Retrospective ultramicroscopic investigation on naturally cryptosporidial-infected commercial turkey poults

The morphometric characteristics and the ultramicroscopic findings of Cryptosporidium spp. at various stages of their life cycle in the intestinal and bursal epithelial cells of naturally infected 30-day-old commercial turkeys are reported. Small, sporulated oocysts, observed in the small intestinal content after flotation, were identified as Cryptosporidium meleagridis on the basis of morphometric characteristics (round in shape and 4.5-5.0 microm in size) and the small intestinal localization. Light section examinations revealed the presence of the protozoon in multiple organs, but its prevalence was highest in the intestinal and bursal epithelial cells. Ultramicroscopic studies on ileum and bursal samples showed the presence of all the life cycle stages in the microvillar brush epithelial cells in both the organs examined. On the basis of the comparison of the morphology and the sizes of the microorganisms parasitizing the ileum and the bursa, hypotheses are considered on the possible species involved.

Immunohistochemical study of S100-like protein in Eimeria brunetti and Eimeria acervulina

We have investigated the expression of a calcium-binding protein, the S100 protein, in Eimeria brunetti and Eimeria acervulina stages. For this purpose, paraffin sections of distal ileum and bursa of Fabricius or duodenum from experimentally infected chickens were treated with anti-alpha-S100 (anti-alpha subunit of S100 protein) and anti-beta-S100 (anti-beta subunit of S100 protein) monoclonal antibodies and anti-S100 whole molecule polyclonal antibody. The avidin-biotin peroxidase method was used to demonstrate immunoreactivity. In the ileum, our results reveal a positive immunoreaction for the beta subunit and S100 whole molecule within the macrogametes of E. brunetti, whereas they were devoid of immunostaining after treatment of the paraffin sections with the anti-alpha-S100 antiserum. Schizonts and oocysts of E. brunetti and all the E. acervulina stages gave a negative reaction after treatment with any of the three antiserum used in the study. This result indicated that the S100 protein molecules within these stages were not recognized by the antibodies, suggesting that these molecules are different from those identified in macrogametes of E. brunetti. By contrast, in the epithelial cells, lining the lumen of the bursa of Fabricius, macrogametes of E. brunetti were stained by the three antibodies used. These results may indicate the existence of metabolic adaptations that enable the parasite to invade tissue sites different from those where the parasite usually develops.

Infectivity to hosts of the endogenous stages of chicken and murine Cryptosporidium

Five groups of 4 mice each were inoculated with 10(6) Cryptosporidium muris oocysts. They were necropsied on days 2, 4, 6, 8 and 10. The stomach mucosa from each group were made into 10% suspension in physiological saline and were orally inoculated to 2 mice each. Recipients given suspension from infected mice on day 6, 8 and 10 shed oocysts from 6, 9 and 6, respectively. Similarly, White Leghorn received 10(6) Cryptosporidium sp. oocysts were killed daily between 1 and 6 days. Recipients given bursa of Fabricius or caecum of donor birds on days 4, 5 and 6 shed oocysts. The endogenous stages of murine and chicken Cryptosporidium were able to infect the appropriate host.

Developmental process of Cryptosporidium in the intestine and bursa of Fabricius of chickens

The developmental process of a Cryptosporidium isolated in Japan in the chicken intestine was investigated by scanning (SEM) and transmission electron microscopies (TEM). The parasites were detected in the ileum, cecum, colon, cloaca and bursa of Fabricius (BF). The intensity of infection tended to peak later in the BF than ileum. Trophozoites and schizonts were detected in all the portions of intestine, and were dominant in the developmental stages. Although macrogamonts were the secondary dominant stage, they were absent in the ileum and cecum at 60 hr postinoculation (PI). A few microgamonts were detected in the ileum at 36 hr PI and in the BF on day 19 PI. Oocysts were observed in the ileum at 48 hr PI and in the BF on day 19 PI.

Cryptosporidiosis in four cockatoos with psittacine beak and feather disease

Cryptosporidiosis was diagnosed in 4 cockatoos with psittacine beak and feather disease. Three of the birds had cryptosporidiosis confined to the epithelium covering the bursa of Fabricius. One bird had generalized parasitism of the small intestine, large intestine, and bursal epithelium. All of the birds had intermittent to protracted diarrhea before death. Presumably, acquired immunodeficiency from psittacine beak and feather disease promoted establishment of cryptosporidiosis and other secondary diseases including septicemia, peritonitis, chlamydiosis, and mycotic ventriculitis.

Pathogenicity of CL-1 chicken anemia agent

Twelve-day-old broiler-type chickens had hemorrhagic necrotic wing tips. After 10 blind subcultures in an MDCC-MSB1 cell line, a virus (so-called chick anemia agent [CAA]) was isolated and designated CL-1 CAA. Five-day-old specific-pathogen-free chicken embryos from a commercial breeder flock that were found not to possess antibody against CAA were infected with CL-1 virus via yolk-sac injection. Many (49%) infected embryos were small and apparently had died from severe systemic hemorrhage. Hatched chicks were small and had pale feathers, skin, skeletal muscles, bone marrow, and viscera. All infected chicks had small thymuses. These thymuses often were so small that they could not be found grossly (P = 0.002). Anemia occurred within 4 days post-hatch. Microscopically, all hematopoietic organs were markedly atrophic. Septic necrotizing lesions were seen only in organs from CL-1-injected chicks. Physicochemical and pathological characteristics of this virus indicate that it is similar to other isolates of CAA found in Europe and Japan.

The relationship of Cryptosporidium sp. infection of the bursa of Fabricius, intestinal tract, and respiratory system of chickens in Georgia, 1974-1988

During 1974-1984, cryptosporidiosis was diagnosed in slightly more than 1% (63/6050 = 1.04%) of histopathology reports on chickens and turkeys made at two Georgia diagnostic laboratories. During 1985-1988, cryptosporidiosis was diagnosed in almost 6% (157/2622 = 5.99%) of histopathology reports on chickens and turkeys made at the two laboratories. Intestinal and respiratory Cryptosporidium sp. infections have increased significantly (p less than 0.01) with time. During the same period, there was no statistical pattern for bursa of Fabricius Cryptosporidium sp. infections, and there was no relationship between the incidence of bursal infections and the incidence of either respiratory or intestinal infections.

Cryptosporidiosis in chickens from southern Spain

Cryptosporidiosis in chickens from southern Spain is reported. Cryptosporidia were found in the trachea, esophagus, and epithelium of the bursa of Fabricius in chickens from different regions. In one flock, cryptosporidiosis was associated with respiratory problems and high mortality. In another flock, it was associated with low mortality and weight loss.

Light-microscopic lesions associated with naturally occurring bursal cryptosporidiosis in chickens

Information concerning histologic significance of naturally occurring bursal Cryptosporidium sp. infection in chickens was obtained by retrospective examination of histopathology reports and clinical data from histology accessions received during 1986. Cryptosporidiosis was diagnosed in 197 bursas. In two-thirds of the accessions, more than 50% of the examined bursas were infected with Cryptosporidium sp. The histologic morphologic lesion diagnosis for Cryptosporidium sp.-infected bursas most often was marked diffuse chronic-active superficial purulent protozoal bursitis with mucosal epithelial hyperplasia. Our study clearly indicates that Cryptosporidium sp. is associated with inflammation and disturbed growth in chicken bursas. Additionally, our data indicate that Cryptosporidium sp. infection is not dependent on bursal damage attributable to other agents, including infectious bursal disease virus.

Cryptosporidial infection in broiler chickens in Greece

Trachea, bursa of Fabricius, and small intestine of broilers 5 to 50 days of age from 10 flocks with varying levels of morbidity and mortality were screened for the presence of Cryptosporidium spp. Cryptosporidial oocysts were found in 24.2% of the examined birds.

Intestinal and bursal cryptosporidiosis in turkeys following inoculation with Cryptosporidium sp. isolated from commercial poults

Cryptosporidium meleagridis oocysts, originally isolated from droppings of commercial turkey poults with increased mortality due to viral (reovirus) hepatitis and enteritis, were treated with peracetic acid to kill companion bacteria and viruses and then propagated by passage in young turkeys. Thirty-eight 5-day-old large white turkey poults were inoculated by crop gavage with 500,000 cryptosporidial oocysts and compared with 40 uninoculated poults. Cryptosporidial oocysts shedding began 3 days postinoculation (PI), peaked on day 4 PI, and persisted at a low level for the duration of the 21-day trial. Low to moderate cryptosporidial infections of the ileal mucosa (days 3, 6, and 15 PI), cecal mucosa (days 3, 6, and 21 PI), and bursa of Fabricius (days 6, 12, 15 and 21 PI) were found on histopathological examination. There were no differences in mean body weights between the inoculated and uninoculated groups, and no mortality or clinical signs of disease were seen in either group.

Development of and serologic evaluation of acquired immunity to Cryptosporidium baileyi by broiler chickens

Eighteen 2-wk-old broiler chickens that were inoculated orally with oocysts of Cryptosporidium baileyi (Group B) became infected, shed large numbers of oocysts in their feces on Days 6 to 12 post inoculation (PI), and suddenly cleared the parasites from the mucosal epithelium of the bursa of Fabricius (BF), cloaca, or both BF and cloaca on Days 14 to 16 PI. Eighteen uninoculated birds (Group A) did not shed oocysts during this time period. Five days after all birds in Group B stopped shedding oocysts, the 36 chickens comprising both groups were challenged orally with C. baileyi oocysts. At the time of necropsy, 10 days after oral challenge, all Group A birds (previously uninfected, challenged) had heavy C. baileyi infections in the mucosal epithelium of the BF or cloaca. No parasites were found in the BF or cloaca of the Group B birds (previously infected, recovered, challenged) at the time of necropsy. These data demonstrate that a single intestinal infection with C. baileyi can elicit an immune response of sufficient magnitude to clear the parasite from the intestinal (BF and cloaca) mucosa and to make broiler chickens resistant to subsequent oral challenge with oocysts of the same species. Development of resistance to reinfection was accompanied by the appearance of serum antibodies to C. baileyi that were detectable by two Cryptosporidium-specific assays; an indirect immunofluorescent antibody assay and an enzyme-linked immunosorbent antibody assay (ELISA). The ELISA described herein can now be incorporated into serologically based health monitoring programs.

Experimental Cryptosporidium infections in chickens: oocyst structure and tissue specificity

Oocysts of an avian isolate of Cryptosporidium were used to inoculate 21 chicks orally and 7 chicks intratracheally to determine the tissue specificity of this organism. Oocysts were passed in the feces 4 to 5 days after inoculation. Oocysts (6.8 by 5.0 microns) were fully sporulated and they were passed for at least 17 days by infected chicks. The mode of inoculation did not influence the distribution of cryptosporidia within the digestive tract. Cryptosporidia were found in the cloaca (100%), bursa of Fabricius (95.7%), terminal portion of the colon (26.1%), and cecum (4.3%) of chicks that were positive for developmental stages. Of 21 chicks inoculated orally, 4 had cryptosporidia in their trachea, whereas 6 of 7 chicks inoculated intratracheally had cryptosporidia in the trachea, bronchi, and air sacs. Cryptosporidium was found in the ducts of the salivary glands and nasal turbinates of chicks inoculated intratracheally that had clinical signs of respiratory tract disease. None of the chicks died or had intestinal disease.

Growth, development and pairing of Leucochloridiomorpha constantiae (Trematoda) metacercariae on the chorio-allantois of chick embryos cultivated in vitro

A simple in vitro technique was devised to culture chick embryos in Petri dishes from the 4th to the 21st day of incubation. Leucochloridiomorpha constantiae (Trematoda) metacercariae were placed either singly or multiply (5/embryo) on the chorio-allantois of in vitro grown embryos on day 7 and were removed on day 14. Growth and development studies were also made on worms grown singly or multiply (5/chick) in the bursa of Fabricius of the domestic chick. Worms grown singly or multiply in embryos were sexually mature, although eggs from these worms were abnormal when compared with eggs from worms recovered from chicks. The mean body area of worms from chicks was 2-3 times greater than that of worms from embryos. The mean body area of single worms from embryos was significantly larger than that of worms grown multiply in this site. However, the mean body area of multiple worms from the chick was significantly larger than that of single worms from this site. Worm pairs or clusters were seen in all embryos with the multiple infections.

Growth, development, and site location of the trematode Himasthla quissetensis in the chick following cloacal drop infections with cercariae

Infections with Himasthla quissentensis were obtained per cloaca in the domestic chick using cercariae. Worms showed a preference for the ileum where they grew and developed to maturity at a rate comparable to those raised in the gull (Stunkard, 1938). Those from the bursa of Fabricius showed relatively little growth and exhibited gonadal atrophy in some instances.

Demonstration of Eimeria tenella in bursa of Fabricius of chickens

Coccidial life-cytle stages were detected in the bursa of Fabricius of broiler chickens inoculated with Eimeria tenella, whether or not the chickens had previously been infected with infectious bursal disease virus (IBDV). Chickens infected only with E. tenella had developing parasites in the lining epithelium, whereas chickens with both infections had gametocytes also in the epithelial cells surrounding numerous degenerating bursal cysts.

Cryptosporidiosis of the bursa of Fabricius of chickens

Light-microscope and electron-microscope studies of a coccidial organism found in the bursa of Fabricius from 3 chickens clearly established the parasite as belonging to the family Cryptosporiidae. Hyperplasia and heterophil infiltration were associated with the presence of organisms attached to the microvillus border of epithelial cells lining the plicae of the bursa of Fabricius. Although there were no clinical signs or gross lesions common to the 3 cases described, all had similar histologic lesions in the epithelium lining the bursa of Fabricius.

Eimeria brunetti in epithelial cells of the bursa of Fabricius in gnotobiotic chickens

Germ-free and conventional chickens were infected with Lactobacillus acidophilus and/or Eimeria brunetti. Germ-free chickens acquiring single infections of E. brunetti were found to have lifecycle stages of the coccidial organism in the bursa of Fabricius.

The helminth parasites of aquatic birds from Loch Leven, Kinross: the trematodes of Laridae

Twelve species of trematode are described from 70 gulls of 5 species examined at Loch Leven. Observations on these trematodes are given with additional morphological details. The environmental origins of the parasites are discussed and related to the habits of the hosts.