Wk Postinoculation Research Articles

Experimental transmission of green turtle fibropapillomatosis using cell-free tumor extracts

DAO Diseases of Aquatic Organisms Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials DAO 22:1-12 (1995) - doi:10.3354/dao022001 Experimental transmission of green turtle fibropapillomatosis using cell-free tumor extracts Herbst LH, Jacobson ER, Moretti R, Brown T, Sundberg JP, Klein PA Green turtle fibropapillomatosis (GTFP), characterized by multiple benign fibroepithelial tumors on the skin and eyes, has become a growing threat to green turtle Chelonia mydas populations worldwide. The cause of GTFP is unknown, but a viral etiology is suspected. This study investigated whether GTFP could be experimentally transmitted to young captive-reared green turtles using cell-free fibropapilloma extracts prepared from free-ranging turtles with spontaneous disease. Turtles raised from eggs collected from 4 separate clutches in the wild were assigned to 4 experimental groups and 1 control group. For each experiment a crude homogenate (33% w/v) was prepared from fibropapillomas removed from a free-ranging turtle with spontaneous disease. The crude tumor homogenates were freeze-thawed and centrifuged to yield cell-free extracts that were used (both filtered and unaltered) for inoculation. Recipients were inoculated by intradermal injection or by scarification; control turtles were not treated but were housed with treated turtles. Fibropapillomas developed in all 12 turtles receiving 3 of the 4 tumor extracts, and were first detected between 15 and 43 wk post inoculation. Both filtered and unfiltered tumor extracts successfully induced tumor development. During the 10 and 12 mo monitoring periods, fibropapillomas did not develop in control turtles or in any turtles inoculated with the fourth tumor extract. Although 2 sets of experiments were performed 8 wk apart, most of the tumors in both sets became evident simultaneously after water temperatures rose. Experimental tumors were histologically indistinguishable from spontaneous fibropapillomas found in free-living turtles but lacked evidence of endo-parasites. Scattered foci of epidermal degeneration were found in most sections of experimentally induced fibropapillomas and within some sections taken from donor turtles. Electron microscopy revealed virus-like particles conforming in size, morphology, and intranuclear location with herpesvirus. Negative-staining electron microscopy of transmission-positive tumor extracts failed to demonstrate intact virus particles. This study demonstrates that the etiology of GTFP is an infectious filterable subcellular agent. The herpesvirus identified in this study is 1 possible candidate for the etiology of GTFP. Sea turtles . Chelonia mydas . Fibropapilloma . Disease transmission Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in DAO Vol. 22, No. 1. Publication date: May 04, 1995 Print ISSN:0177-5103; Online ISSN:1616-1580 Copyright © 1995 Inter-Research.

EXPERIMENTAL INFECTION OF BORRELIA BURGDORFERI IN WHITE-TAILED DEER

Four white-tailed deer (Odocoileus virginianus) were experimentally inoculated with Borrelia burgdorferi to determine serologic response by enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Deer had antibodies by ELISA by 2 to 3 wk post-inoculation (PI) and remained positive for 10 wk. Deer demonstrated immunoblotting reactivity between 10 and 14 days PI and consistently showed antibody response to nine B. burgdorferi antigens. Attempts were made to recover the spirochete from blood and tissues; B. burgdorferi was isolated from an ear punch biopsy from one of the inoculated deer.

Detection of Salmonella enteritidis in Experimentally Infected Laying Hens by Culturing Pools of Egg Contents

Two experiments were conducted to determine whether Salmonella enteritidis could be detected efficiently in pooled samples of contents of eggs laid by experimentally infected hens. In Experiment 1, groups of laying hens were orally inoculated with either 104 or 106S. enteritidis cells. In Experiment 2, one-third of the hens in each group were orally inoculated with 106S. enteritidis cells. At 2 wk postinoculation, culturing egg pools yielded positive results at frequencies similar to those obtained by culturing fecal samples, culturing internal organs, or testing for specific serum antibodies. Culturing fecal samples detected a higher percentage of exposed hens than egg pool culturing at 1 and 3 wk, and serum antibody tests were superior at 3 and 4 wk. In Experiment 1, more than 46% of the hens inoculated with 106S. enteritidis cells laid at least one contaminated egg during the 2nd wk postinoculation. In Experiment 2, over 34% of the hens produced at least one contaminated egg during the 2nd wk postinoculation, but very few contaminated egg pools were identified during the 3rd and 4th wk. Bacteriological culturing of pooled egg contents for S. enteritidis, therefore, can apparently provide an effective method for assessing the potential public health threat posed by a flock.

Equine Protozoal Myelitis in Panamanian Horses and Isolation of Sarcocystis neurona

Schizonts of Sarcocystis neurona were identified microscopically in hematoxylin-eosin-stained spinal cord sections from 2 native Panamanian horses that exhibited clinical signs of equine protozoal myelitis (EPM). Spinal cord homogenate from a third Panamanian horse with EPM was inoculated onto monolayers of cultured bovine monocytes (M617). Intracytoplasmic schizonts containing merozoites arranged in rosette forms surrounding a central residual body first were observed 13 wk postinoculation. Parasites divided by endopolygeny and lacked rhoptries. Schizonts from each horse reacted with Sarcocystis cruzi antiserum in an immunohistochemical test.

Serologic Response of the Opossum Didelphis virginiana to a Temperature-Sensitive Mutant (ts-4) of Toxoplasma gondii

A study was designed to measure the Toxoplasma gondii-specific IgM and IgG antibody responses of opossums inoculated with tachyzoites of the temperature-sensitive mutant of T. gondii, ts-4, and to examine its persistence in the tissues. Four young opossums seronegative for anti-Toxoplasma gondii IgM and IgG antibodies immediately after capture and 4 wk later were injected subcutaneously with 1.8 x 10(6) ts-4 tachyzoites; a fifth opossum (also seronegative) received an injection of saline only. Serum was collected weekly and titered by modified direct agglutination for anti-Toxoplasma gondii IgM and IgG. IgM titers were detectable from week 1 to week 6 postinoculation (PI). IgG was measurable by week 3 and remained high for 30 wk PI when the opossums were killed and examined. The control opossum did not develop a specific antibody response. At necropsy major lesions were not found. No anti-Toxoplasma gondii IgG was detected in serum collected from mice injected with tissues prepared from the opossums at necropsy, and no T. gondii was found on impression smears made at necropsy from these mice. Modified direct agglutination performed with or without 0.2 M 2-mercaptoethanol worked well for measuring specific IgM and IgG antibodies in experimentally infected opossums.

Alterations in mRNA levels for growth-related genes after transplantation into castrated hosts in oncogene-induced clonal mouse prostate carcinoma.

A clonal mouse prostate carcinoma was established by the introduction of the ras and myc oncogenes via the recombinant retrovirus Zipras/myc 9 using a mouse prostate reconstitution model system. A single-cell suspension derived from an early passage ras+myc-induced carcinoma was inoculated into the flanks of intact or castrated adult male C57BL/6 mice, and tumors were harvested 3 wk postinoculation for northern and Southern blotting. Tumor volume analysis showed that this carcinoma was not dependent on testicular androgens for growth. Southern blot analysis of virus-cell DNA junction fragments revealed that tumor cell populations recovered from both intact and castrated mice were progeny of the same virus-infected cell. Northern blotting showed that mRNA levels for the four growth-related genes transforming growth factor-beta 1 (TGF-beta 1), transforming growth factor-beta 3 (TGF-beta 3), tissue-type plasminogen activator (tPA), and c-myc were significantly elevated in clonal mouse prostate carcinomas grown in castrated hosts. In contrast, androgen receptor mRNA levels were significantly reduced under the same conditions. The response of TGF-beta 1, tPA, and c-myc mRNA levels in the carcinomas grown in castrated hosts was similar to that shown previously in normal rat ventral prostate. However, unlike normal rat ventral prostate after castration, increased numbers of apoptotic cells were not seen in the castrated group relative to the intact group at the time of analysis, indicating that the altered gene expression was not associated with cell death. In addition, testosterone-repressed prostate mRNA number 2 levels, shown previously to be elevated after castration in normal rat ventral prostate, were not increased in the androgen-deprived clonal mouse prostate carcinomas. Therefore, this early passage clonal ras+myc-induced prostate carcinoma demonstrates unique patterns of expression for a set of growth-related genes in an androgen-deprived environment.

Guatemalan human onchocerciasis. II. Evidence for IgG3 involvement in acquired immunity to Onchocerca volvulus and identification of possible immune-associated antigens.

Abstract Ag-specific isotypic differences in immune response to Onchocerca volvulus Ag were assessed for 778 long term residents of endemic Guatemalan areas by quantitative ELISA with 5-min incubation steps and immunoblot. The study population was separated into five groups based on clinical status: N+F+, N+F-, N-F+, N-F-H+, and N-F-H-, where N = O. volvulus adults (nodule), F = microfiladermia, and H = history of O. volvulus infection. A subset of 44 individuals with high exposure to onchocerciasis from the N-F-H- group were critically evaluated and designated as "putatively immune." IgG1 reactivity to O. volvulus Ag was elevated in the majority of infected persons, but not in putatively immune individuals. Specific IgG3 levels, however, were equally elevated in all groups. The majority of N+F- persons also had elevated IgG1 levels, but they were lower than those found in F+ persons. IgG3 reactivities to a group of antigens at 20 kDa (GP20) were seen in many uninfected persons and some N+F- persons. In contrast, most F+ persons, react to this Ag with IgG1 and not IgG3. A mangabey inoculated with the infectious larval stage of O. volvulus (L3), but showed no signs of infection, began to recognize GP20 at 2 wk postinoculation. Early recognition of GP20 was possibly elicited by the larval stage. Purified nodule Ag from N+F+ individuals contained GP20, however, identical nodule Ag prepared from N+F- individuals did not. These data suggest that GP20 Ag may be common to both uterine microfilaria and the infectious larval stages. The fact that GP20 is predominantly recognized by IgG3 in putatively immune persons and some N+F- persons suggests that this increased IgG3 activity may be important in acquired immunity to onchocerciasis.

Research Note: Detection of Salmonella Serogroup D-Specific Antibodies in the Yolks of Eggs Laid by Hens Infected with Salmonella enteritidis

Eggs laid by hens experimentally infected with Salmonella enteritidis were assayed for the presence of Serogroup D-specific yolk antibodies. Yolk: antibodies were detected with S. enteritidis and Salmonella pullorum antigens in the microantiglobulin test as early as 9 days after inoculation of hens with S. enteritidis. Yolk antibody titers reached peak levels at 3 to 5 wk postinoculation and remained at detectable levels for at least 7 wk postinoculation in eggs from both orally inoculated and horizontally contact-exposed hens. Eggs laid by hens from commercial flocks implicated in epidemiological investigations of human S. enteritidis outbreaks were also tested. Serogroup D-specific yolk antibodies were detected in 5 to 22% of eggs from hens in houses identified as infected by bacteriological culturing of internal organs of hens for S. enteritidis.

Toxoplasma gondii Infections in Red-Tailed Hawks Inoculated Orally with Tissue Cysts

The response to inoculation of Toxoplasma gondii tissue cysts was examined in 3 red-tailed hawks (Buteo jamaicensis). One hawk (hawk 1) was inoculated orally with 3.000 tissue cysts of the GT-1 isolate of T. gondii and 2 hawks (hawks 2 and 3) each were inoculated orally with 12,000 tissue cysts of a mixture of 8 isolates of T. gondii. None of the hawks developed clinical signs of toxoplasmosis. Serum antibodies were measured with the modified direct agglutination test using formalin-fixed tachyzoites. Hawk 1 had a titer of 1:40 prior to inoculation and did not have an increase in titer during the study. Hawks 2 and 3 had titers of 1:5 and 1:10, respectively, prior to inoculation, and both had increased titers (titers greater than or equal to 1:60) by 1 wk postinoculation and remained T. gondii antibody positive throughout the 10 wk of the study. Toxoplasma gondii was isolated from the heart and breast muscle of hawk 1. The biologic behavior of this T. gondii isolate was different from the 1 inoculated, and it probably represents a prior natural infection. Toxoplasma gondii was isolated from the brain, heart, breast muscle, and a mixture of gizzard and proventriculus from hawk 2 and from breast muscle of hawk 3. Toxoplasma gondii was not isolated from the eye, lung, liver, kidney, or spleen of any red-tailed hawk.

Aberrant expression of cytokine genes in peritoneal macrophages from mice infected with LP-BM5 MuLV, a murine model of AIDS.

Mice infected with LP-BM5 murine leukemia virus (MuLV) develop a syndrome denoted as murine AIDS. Macrophages harvested from the peritoneal cavities of these mice at 4 or 9 wk postinoculation with LP-BM5 MuLV were analyzed by Northern hybridization for the presence of the defective LP-BM5 virus and their ability to synthesize various cytokines upon induction with Newcastle disease virus (NDV) or (LPS). Neither IFN-alpha or IFN-beta was found to be constitutively expressed in LP-BM5-infected macrophages and in NDV induction studies, and the levels of biologically active IFN-alpha and its mRNA were found to be lower in LP-BM5 MuLV-infected macrophages than in the macrophages from uninfected controls. Similarly, after NDV or LPS induction, the levels of TNF mRNA and TNF protein were significantly lower in LP-BM5-infected macrophages than in macrophages from uninfected mice. The LP-BM5 MuLV-infected macrophages constitutively expressed low levels of IL-1 beta, and when induced with LPS, the relative levels of IL-1 beta were significantly higher in infected than in uninfected macrophages. Although no constitutive expression of IL-6 was detected, the levels of IL-6 mRNA induced with NDV were higher in LP-BM5 MuLV-infected macrophages than in controls. Thus, we found alterations in the expression of selected cytokines in macrophages from mice inoculated with LP-BM5 MuLV rather than a general deregulation of all cytokine expression. These results show that macrophages infected with the defective LP-BM5 virus respond differently to NDV- or LPS-stimulation and suggest that aberrant expression of certain cytokine genes may play a role in the immunopathologic condition in mice with murine AIDS.

Transmammary Transmission of Mesocercariae of Alaria Marcianae (Trematoda) in Experimentally Infected Primates

A lactating primate, Callithrix jacchus, was infected experimentally with 600 mesocercariae of Alaria marcianae 10 days after parturition to determine if she would transmit the mesocercariae to her offspring. Her twin infants were examined 4 wk postinoculation and 16 mesocercariae were found in their tissues. The female was mated again and gave birth to a litter of triplets. She was not given additional mesocercariae. One infant died within hours of birth without suckling and was found negative for any stage of A. marcianae. The other 2 were allowed to nurse for 5 wk, examined and found to be infected with a total of 115 mesocercariae in various tissues, 1 metacercaria in the lungs, and 1 immature and 2 fully formed ovigerous adults in the small intestines. The female was examined at the same time and 246 mesocercariae were recovered. No other stage was found. Histological examination of her mammary glands revealed numerous mesocercariae in the milk-laden alveoli.

Decreased Pulmonary Vasoreactivity in an Animal Model of ChronicPseudomonasPneumonia

Chronic pulmonary infection/colonization caused by Pseudomonas aeruginosa accounts for much of the morbidity and mortality in cystic fibrosis (CF). The effect of chronic pulmonary P. aeruginosa infection on the pulmonary circulation has not been studied. Therefore, we investigated the effect of chronic P. aeruginosa infection on pulmonary hemodynamics in a rat model. Two groups of rats were inoculated with either agar beads containing 1.0 x 10(4) colony-forming units of P. aeruginosa (infected) or an equal volume of sterile beads alone (control). In vivo, pulmonary vasoreactivity measured as the percent change in total pulmonary resistance during hypoxia was decreased at 1 wk (22 +/- 7% versus 57 +/- 3%), 2 wk (29 +/- 5% versus 73 +/- 17%), 3 wk (41 +/- 8% versus 77 +/- 14%), and 6 to 9 wk (23 +/- 10 versus 53 +/- 7; p less than 0.05 all time points; mean +/- SEM) postinoculation in infected animals when compared with that in time-matched control animals. At 6 to 9 wk postinoculation, pulmonary artery pressure was significantly elevated in infected rats (25.8 +/- 1.6 versus 21.0 +/- 1.0 mm Hg; p less than 0.05) when compared with that in control animals. Histopathologic findings were characterized by bronchiectasis as well as by chronic bronchial, parenchymal, and perivascular inflammation at all time points in infected animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of Two Strains of Grapevine Virus A

Two isolates of grapevine virus A (GVA), mechanically transmitted from leafroll-affected grapevine cultivars to Nicotiana benthamiana and designated SA646 and SA36, were purified from in vitro node cultures of N. benthamiana and reinoculated into N. benthamiana seedlings. Symptom development differed reproducibly between the two isolates. At 3 wk postinoculation, the N. benthamiana inoculated with GVA isolate SA646 showed a systemic dwarfing with vein ckearing of the tertiary and smaller veins, whereas those inoculated with isolate SA36 showed a systemic dwarfing with a pronounced interveinal chlorosis. The strains were not serologically distinguishable using either of two polyclonal antisera

Age-Related Changes in the Persistence and Pathogenicity of Salmonella typhimurium in Chicks

Effects of age at exposure on the persistence of Salmonella in various tissues of chicks were assessed in two experiments. Broiler chicks, housed on wire floors in isolation cabinets, were orally inoculated with S. typhimurium at various ages (1 to 8 days after hatching). The postinoculation mortality of chicks declined significantly (P<.05) as the age at inoculation increased. One experiment investigated the effect of age at inoculation on the persistence of S. typhimurium in the cecum. Salmonella persisted for 7 wk after inoculation in 81.3% of the chicks inoculated at 1 day of age and in 62.5% of the chicks inoculated at 8 days of age. The mean number of cecal Salmonella at 7 wk postinoculation was also greater for chicks inoculated on Day 1 than for those inoculated on Day 8. The second experiment examined the effect of age at inoculation on the adherence of S. typhimurium to and penetration through the cecal epithelium. The ceca of chicks inoculated at 1 day of age were colonized by significantly more adhering Salmonella at 2 days postinoculation (1.4 × 108/g) than were those of chicks inoculated at 3, 5, or 7 days of age (8.0 × 166/g or less), but age did not affect the recovery of S. typhimurium from livers or spleens.

DETECTION AND OCCURRENCE OF PRIMARY INFECTION BY POTATO VIRUS S OF DISEASE-FREE PLANTS

Using enzyme-linked immunosorbent assay (ELISA) and potato plantlets of cultivars Green Mountain, Red Pontiac, Russet Burbank and Shepody, potato virus S (PVS) was detected in primary infected plants under field conditions. Potato virus S was detected 3 wk postinoculation (p.i.) from the field-grown plants as compared to 2 wk p.i. from greenhouse-grown plants. Potato virus S concentration in infected plants remained high throughout the growing season. The ELISA test using dormant tubers was not reliable because A405 nm values overlapped between infected and healthy tubers. Exposure of healthy plants to PVS sources in the field resulted in high infections with PVS by the 9th wk of growth. This pattern of infection suggests involvement of aerial vectors in the transmission of PVS under conditions of the Atlantic region of Canada.Key words: Current year infection, ELISA, dormant tubers, spread of PVS

Clinical, histologic and scanning electron microscopic study of the development of chronic candidiasis of the rat tongue.

In order to examine the development of the chronic candidal lesion of the dorsal rat tongue, 210 rats were given a single oral inoculum of Candida albicans on Day 0 and were sequentially killed over a 20-wk period. Dorsal tongue changes were evaluated using clinical photographs, histologic sections and scanning electron microscopy (SEM). Clinically evident lesions became apparent at 2 wk post-inoculation, and inflammatory changes of the underlying connective tissue were observed by 3 wk post-inoculation. SEM showed a gradient of destruction of the dorsal tongue papillae at the periphery of the candidal lesions. Hyphae were seen infrequently on the lesional surface by SEM, a finding which correlated with the light microscopy.

Characteristics of B cell proliferation and activation in murine AIDS.

A syndrome characterized by lymphadenopathy, hypergammaglobulinemia, and immunodeficiency develops in C57BL/6 mice inoculated with LP-BM5 murine leukemia viruses. By studying the number and antigenic specificity of B cells activated in the course of this disease, we found that a series of reproducible changes in the humoral immune system were induced by retroviral infection. The rate of B cell proliferation and the proportion of B cells activated to secrete Ig increased by nearly 10-fold at 4 wk post inoculation. B cells producing antibodies reactive with a panel of three conventional Ag and five autoantigens were stimulated simultaneously and proportionally to secrete, demonstrating that such activation was polyclonal in nature. At 12 wk post infection, the number of Ig-secreting B cells continued to rise and significant hypergammaglobulinemia developed. At 16 wk post infection, immunostimulation gave way to immunosuppression, as evidenced by a slight decline in the number of Ig-secreting lymphocytes and a sharp reduction in the concentration of serum antibody. At this time, the B cell repertoires of infected mice diverged markedly from those of uninfected animals. These changes are comparable to those found in some patients infected with HIV, and provide a useful model to study the association between retroviral infection and regulatory abnormalities of the humoral immune system.

Abnormal regulation of IFN-alpha, -beta, and -gamma expression in MAIDS, a murine retrovirus-induced immunodeficiency syndrome.

Mice infected with LP-BM5 murine leukemia viruses (MuLV) develop a syndrome with many features in common with AIDS including lymphadenopathy and profound immunodeficiency associated with enhanced susceptibility to infection and terminal B cell lymphomas. To evaluate cellular defects that may predispose infected mice to these sequelae, we studied the regulation of IFN gene expression. Spleen cells from mice infected with LP-BM5 MuLV expressed high levels of IFN-gamma mRNA by 1 wk post-inoculation and throughout the course of disease. By comparison, transcripts of IFN-alpha/beta genes were not detected in spleen cells at any time after infection. In uninfected mice, expression of IFN-alpha/beta genes is induced rapidly after infection with New-castle disease virus, but mice inoculated with LP-BM5 MuLV were unable to induce these genes by 4 wk after retroviral infection. Inhibition of IFN-alpha/beta induction due to LP-BM5 MuLV infection also occurred in nude mice, indicating this effect was not mediated by activated T cells. Furthermore, low levels of IFN-gamma transcripts were detected in spleens of nude infected mice, suggesting that cells other than T cells can express this gene. These results suggest that the normal contributions of IFN to control of microbial spread, immune surveillance, and lymphoid interactions are disrupted by infection with LP-BM5 MuLV.

SUSCEPTIBILITY OF WHITE-TAILED DEER TO EXPERIMENTAL HEARTWATER INFECTIONS

Nine white-tailed deer (Odocoileus virginianus) were experimentally infected with Cowdria ruminantium, the causal agent of heartwater. All deer developed clinical signs; one was killed, one was treated, and seven died within 2 wk postinoculation. Diagnosis of heartwater was based on clinical signs, postmortem lesions and by microscopic observation of C. ruminantium in endothelial cells of brain capillaries of dead animals. Cowdria ruminantium was passaged by collecting blood from deer at the height of the febrile response and intravenous inoculation of susceptible deer and goats. Tetracycline was effective in the treatment of heartwater in a deer.

Enzyme-Linked Immunosorbent Assay to Detect Antibody Response against Eimeria bovis and Eimeria zurnii in Calves

In the United States, bovine coccidiosis is primarily a disease of young calves, 6 to 9 mo of age (Fitzgerald, 1975, Bovine Practice 10: 2833). Eimeria zurnii and Eimeria bovis are considered to be the 2 most pathogenic species of cattle (Levine and Ivens, 1970, The coccidian parasites [Protozoa, Sporozoa] of ruminants. University of Illinois Press, Urbana, Illinois). Early detection of the clinical coccidiosis before production of the oocysts, by means of serological methods, may be useful in identifying the infected animals, thereby enabling early and effective treatment. The enzyme-immunosorbent assay (ELISA) has been reported to be sensitive and effective in detecting the serum antibodies against chicken coccidiosis (Rose and Mockett, 1983, Parasite Immunology 5:479-489; Saatara Oz et al., 1984, Journal of Parasitology 70: 859-863). This led to the present investigation of cross-reactivity between a soluble antigen of Eimeria tenella and sera from calves infected with E. zurnii and/or E. bovis. Lack of species specificity might allow the use of a purified avian coccidia antigen to identify coccidiosis in cattle. Twenty Holstein calves were purchased at about 1 wk of age and maintained in indoor pens. Fecal samples were collected before and during the experiment. The calves had not produced oocysts of any species prior to oral inoculation. About 5 wk after purchase, they were divided into 4 groups and were inoculated orally with sporulated oocysts of E. bovis and/or E. zurnii as described below. Group A: 4 calves received 150,000 oocysts of E. bovis (95% pure). Group B: 4 calves received 230,000 oocysts of E. zurnii (78% pure). Group C: 6 calves received 300,000 oocysts of E. bovis and 500,000 oocysts of E. zurnii. Group D: 6 calves were kept as uninfected controls. Contaminating oocysts present were Eimeria auburnensis, Eimeria cylindrica, and Eimeria ellipsoidalis. Calves were bled via the jugular vein prior to inoculation and then weekly to 5 wk post-inoculation (4 wk PI for the E. bovis and E. zurnii group). All of the sera collected were stored at 20 C. Sixteen sera were randomly collected from colostrum-deprived calves that were not positive for coccidia on fecal exam (birth to 13 wk of age) and were used as additional uninfected control