Sepsis and bacterial suppurative meningitis-meningoencephalitis in critically ill neonatal Piedmontese calves: clinical approach and laboratory findings

Sepsis (S) and bacterial suppurative meningitis-meningoencephalitis (M-ME) are common causes of death in bovine neonates. The aim of this prospective study was to evaluate the prevalence of S and M-ME in critically ill neonatal Piedmontese calves. Critically ill animals up to 15 days old referred by practitioners were registered according to their status and subsequently assigned to clinical standardized score. Calves with a clinical score > = 5 were further assessed under a clinical and clinical-pathological protocol to strengthen the suspicion of S and M-ME. Critically ill neonatal calves sent for necropsy were included in the study as well. Fifty-nine calves were investigated, 26 of which referred alive and 33 dead. Ten out of the 26 clinically evaluated calves were classified as suspicious of S on the basis of the clinical and clinical-pathological protocols. S was confirmed by positive bacteriologic culture in 7 cases and in 3 cases on the basis of necroptic lesions. Concomitant suppurative M-ME suspected in 6 of these 10 calves was subsequently confirmed by CSF analysis or histological findings. Of the 33 calves examined only post-mortem, 20 showed pathognomonic findings of S and 14 signs of M-ME. The prevalence of S and M-ME was 46 and 36 %, respectively. Clinical signs of S were confirmed to be vague and overlapping with other diseases. The developed protocol was highly accurate in predicting S in these neonatal calves.     

Prevalence of Clostridium perfringens in faeces and ileal contents from grass sickness affected horses: Comparisons with 3 control populations

Reasons for performing study: While previous studies have demonstrated an association between equine grass sickness (EGS) and the presence of Clostridium botulinum within ileal contents and faeces, no such associations with other intestinal‐derived anaerobic bacteria have been extensively investigated. Hypothesis: The prevalence of C. perfringens in the ileal contents and faeces of EGS horses is greater than control horses; the detection of C. perfringens in faeces by ELISA could be diagnostically beneficial in a clinical setting. Methods: The prevalence of C. perfringens in faeces from EGS horses and healthy grazing control horses was determined by both selective culture and ELISA to permit both validation of the ELISA and inter‐group comparisons. Additionally, the prevalence of C. perfringens (ELISA) in ileal contents from EGS horses was compared with that for control horses with nongastrointestinal disease. Finally, the prevalence of C. perfringens (ELISA) in faeces from EGS cases was compared with that from both horses with which they shared pasture at the time of disease onset and non‐EGS colic horses. Results: When compared with culture, the ELISA had a sensitivity and specificity of 86 and 98%, respectively. The prevalence of C. perfringens in faeces as determined by both culture and ELISA was significantly higher (P<0.001) for EGS horses (7/9 and 15/37, respectively) than for healthy grazing controls (0/60 and 1/74, respectively). The prevalence of C. perfringens in ileal contents from EGS horses (5/10) was greater than that for horses with nongastrointestinal disease (1/12) at a level that approached significance (P = 0.056). EGS cases had a significantly greater prevalence of C. perfringens in faeces (15/37) than co‐grazing horses (1/18) and colic (1/16) horses. The specificity (93%) and PPV (94%) of the detection of C. perfringens by ELISA on faecal samples in relation to disease status (EGS compared with colic horses) was good. Sensitivity (41%) and NPV (39%) were poor. Conclusions and potential relevance: The use of a commercial ELISA to detect faecal C. perfringens may be diagnostically beneficial when differentiating EGS cases from colic cases, although further work is required to fully evaluate its potential.     

Field validation of a real-time PCR test for the detection of Mycoplasma hyopneumoniae in nasal swabs of live pigs

Enzootic pneumonia (EP) of pigs, caused by Mycoplasma hyopneumoniae has been a notifiable disease in Switzerland since May 2003. The diagnosis of EP has been based on multiple methods, including clinical, bacteriological and epidemiological findings as well as pathological examination of lungs (mosaic diagnosis). With the recent development of a real-time PCR (rtPCR) assay with 2 target sequences a new detection method for M. hyopneumoniae became available. This assay was tested for its applicability to nasal swab material from live animals. Pigs from 74 herds (average 10 pigs per herd) were tested. Using the mosaic diagnosis, 22 herds were classified as EP positive and 52 as EP negative. From the 730 collected swab samples we were able to demonstrate that the rtPCR test was 100% specific. In cases of cough the sensitivity on herd level of the rtPCR is 100%. On single animal level and in herds without cough the sensitivity was lower. In such cases, only a positive result would be proof for an infection with M. hyopneumoniae. Our study shows that the rtPCR on nasal swabs from live pigs allows a fast and accurate diagnosis in cases of suspected EP.     

Construction and validation of a risk-screening questionnaire for the investigation of recurrent airway obstruction in epidemiological studies of horse populations in Great Britain

Recurrent airway obstruction (RAO) is an environmental respiratory disease affecting horses. A risk-screening questionnaire (RSQ) for RAO would provide a useful tool to investigate the epidemiology of the disease in horses; our aim in this study was to construct and validate such an instrument. Guidance for what questions to include in the RSQ came from three processes: a review of the scientific literature, a survey of equine practitioners in the UK and a consultation with 19 experts using a modified Delphi technique. The latter consultation consisted of two rounds; agreement amongst the experts increased between the rounds. The quantitative outputs provided estimates of the probabilities of a horse having RAO for each particular piece of historical information or clinical sign. The RSQ for RAO was a short questionnaire for completion by horse owners regarding the horse, its health and its management. The likelihood of a horse having RAO (the RAO score) was calculated from a completed RSQ by combining the relevant estimated probabilities. The RSQ was validated against a reference standard of a veterinary diagnosis including respiratory cytology. This was achieved by inviting veterinary surgeons (residing in Great Britain who had taken part in the practitioner survey, and who had indicated that they used respiratory cytology in the diagnosis of respiratory cases) to participate. During 2003 and 2004 these veterinary surgeons returned RSQs for 40 cases that underwent investigation of the respiratory tract and 40 controls; 18 of the cases were given a final diagnosis of RAO. A receiver-operating characteristic (ROC) curve was used to select a positive cut-off of 0.87 for the RSQ for RAO. This suggested that the RSQ had a sensitivity of 0.83 (95% confidence interval=0.59-0.96) and specificity of 0.85 (0.74-0.93) for the diagnosis of apparent RAO (compared to all other diagnoses).     

A comparison of counter-immunoelectrophoresis with the rose bengal and the serum tube agglutination tests in the diagnosis of brucellosis in sheep

The counter-immunoelectrophoresis test (CIEPT) was compared with the rose bengal plate test (RBPT) and the serum agglutination test (SAT) in the diagnosis of brucellosis in 241 sheep. The total number of animals positive by one or more of the tests used was 106. Sixty animals were positive by all tests, while 87, 79 and 80 were positive by CIEPT, RBPT and SAT respectively. Based on the assumption that animals with an SAT titre of 40 I.U./ml or above were true positives, the CIEPT had a sensitivity of 82.5% and a specificity of 78.3% compared to 96.5% and 87% respectively, demonstrated by the RBPT. CIEPT might be used in flocks without clinical evidence of ram epididymitis if a test to supplement RBPT were required; but it would only partially replace SAT. Sera positive in RBPT but negative in CIEPT would have to be tested by SAT. With this combination, only about 22% of sera positive in RBPT would need to be further tested by SAT.     

Bovine leucosis (lymphosarcoma): a clinical study of 60 pathologically confirmed cases

The clinical features of 60 pathologically confirmed cases of bovine leucosis (lymphosarcoma) are described. The majority of cases could be classified into one of four distinct clinical forms, ie, juvenile multicentric, thymic, skin and adult multicentric. Diagnosis of leucosis in animals with these forms was possible on clinical grounds alone. Five animals, four of which were adult, could not be thus classified and diagnosis required haematological and, or, pathological examinations. The clinical, epidemiological and serological findings would suggest that the cases were examples of sporadic bovine leucosis.     

Comparing FAMACHA eye color chart and Hemoglobin Color Scale tests for detecting anemia and improving treatment of bovine trypanosomosis in West Africa

African animal trypanosomosis (AAT) is considered the most important cattle disease in sub-Saharan Africa but its diagnosis in the field is difficult, resulting in inappropriate treatments, excessive delay in treatments and under-treatment. A field study in West Africa investigated the usefulness of anemia in the diagnosis of trypanosomosis. A total of 20,772 cattle blood samples were taken from 121 villages in 3 countries. The average packed cell volume (PCV) of trypanosomosis positive cattle was 23%, versus 28% for negative cattle. In a sub-set of animals, other causes of anemia were investigated showing most of the anemia burden was attributable to trypanosomosis. Anemia was a reasonably accurate indicator of trypanosomosis in the study area, with a sensitivity of 56% and a specificity of 80% and a diagnostic odds ratio of 4.2, the highest of all the signs evaluated (anemia, emaciation, staring coat, lymphadenopathy, fever, lacrimation and salivary or nasal discharge). Having confirmed the usefulness of anemia as a predictor of trypanosomosis, two potential pen-side tests for anemia were evaluated (the first reported trial of their use in cattle), firstly a color chart developed for anemia detection in sheep through visual inspection of conjunctival membranes (FAMACHA) and secondly the Hemoglobin Color Scale (HbCS) developed for assessing hemoglobin levels in human patients by comparing blood drops on filter paper with color standards. In a population of cattle suspected by their owners to be sick with trypanosomosis (n=898) the sensitivity of the HbCS test was 56% and the specificity was 77%, while the sensitivity of the FAMACHA test was 95% and the specificity was 22%. The higher sensitivity but lower specificity suggests the FAMACHA may be useful as a screening test and the HbCS as a confirmatory test. The two tests were also evaluated in cattle randomly selected from the village herd. Using cut-off points to optimize test performance, the HbCS test had a sensitivity of 81% and a specificity of 62% (n=505 cattle), while the FAMACHA had a sensitivity of 92% and a specificity of 30% (n=298 cattle). Recommendations are made for the appropriate use of these tests in the West African region.     

Use of Brucella canis antigen for detection of ovine serum antibodies against Brucella ovis

Brucella ovis causes a genital disease of sheep manifested by epididymitis in rams and placentitis in ewes producing reduced fertility in the flock. Clinical diagnosis is not sensitive enough and bacteriological testing is not feasible for detection of the disease in large numbers of animals. Indirect methods of serological testing are preferred for routine diagnosis, of which agar gel immunodiffusion (AGID), complement fixation (CF) and ELISA tests are recommended as the most efficient. Since B. ovis shares antigenic components with Brucella canis, it would seem that either strain could be used as antigen with the same results; however, the advantage of the B. canis (M-) strain variant is that it can be used to develop a satisfactory antigen for agglutination tests. We present data on AGID and IELISA tests using B. ovis antigen and rapid screening agglutination test (RSAT), 2-mercapto-ethanol RSAT (2ME-RSAT) and IELISA using B. canis antigen. We tested 225 animals. The cut-off values were adjusted by ROC analysis using 51 negative and 32 positive sera; the IELISA-B. canis cut-off value was 39 (%P) and IELISA-B. ovis, 51 (%P), with 100% sensitivity and specificity. Of the 32 positive sera from the infected flock RSAT detected 32 (100%), 2ME-RSAT 29 (91%) and AGID 31 (97%). Of the 142 sera from suspicious flocks, 46 were negative and 56 positive in all the tests; 16 were positive by RSAT, IELISA-B. canis and IELISA-B. ovis, 20 positive only with RSAT and 2 positive only by both IELISAs. RSAT is a very sensitive screening test that, because of its simplicity and easy interpretation, following a study in larger sample, could replace AGID as a screening test for diagnosis of ovine brucellosis caused by B. ovis. The IELISA-B. canis or IELISA-B. ovis could be used as confirmatory tests, since they show equal specificity and sensitivity.     

Interpretation of California mastitis test scores using Staphylococcus aureus culture results for screening of subclinical mastitis in low yielding smallholder dairy cows in the Dar es Salaam region of Tanzania

Screening of subclinical mastitis under field conditions is done using the California mastitis test (CMT). CMT score of ≥1 corresponding to ≥500,000 somatic cells ml⁻¹ is commonly used as threshold of subclinical mastitis in temperate countries. However, given the innately high physiological level of somatic cells in low yielding dairy cows, this threshold may not apply to low yielding dairy cows. The current study was undertaken to investigate the clinical utility of CMT for screening of Staphylococcus aureus subclinical mastitis in low yielding smallholder dairy cows in Tanzania. A total of 1151 of quarter-milk samples were CMT tested, of these 914-originated from cows with a lactation period of 14–305 days. All samples were screened for subclinical mastitis by the CMT as well as microbiological culture of single, duplicate (two consecutive) and triplicate (three consecutive) samples as a gold standard. For the duplicate and triplicate quarter-samples, cows were considered positive for S. aureus subclinical mastitis if results of microbiologic culture for S. aureus were positive for two of two, and for at least two of the first three consecutive quarter-milk samples collected from that cow, respectively. Using a CMT score of ≥1 would classify 78.6% of the 940 quarter-samples as positive. Eighty-two percent of the samples in which S. aureus was isolated had CMT scores ≥2; this would classify 51.6% of the 940 quarter-samples as positive. For the single sample, this cut-off had sensitivity, specificity and likelihood ratio for S. aureus of 0.87, 0.83 and 4.24, respectively. For the duplicate quarter-milk samples this cut-off had sensitivity, specificity, and likelihood ratio of 0.94, 0.86, and 5.19. While, for the triplicate quarter-milk samples this cut-off had sensitivity, specificity and likelihood ratio of 0.97, 0.92 and 7.47, respectively. Based on these results and practical considerations, it is concluded that CMT score of ≥2 corresponding to ≥800,000 somatic cells Ml⁻¹ is the best cut-off to correctly identify S. aureus intramammary infections in low yielding dairy cows in Tanzania.     

Ultrasonography of small intestinal obstructions: a contemporary approach

Objectives : To assess the accuracy of intestinal ultrasound for diagnosis of intestinal obstruction in dogs and cats. Methods : A prospective clinical study was performed. Inclusion criteria were dogs and cats with clinical signs suggestive of gastrointestinal obstruction. Animals with no obstruction detected on ultrasound were excluded if they could not be monitored for 48 hours to confirm absence of obstruction. Sonographic diagnosis of small intestinal obstruction was based on identification of at least two findings suggestive of intestinal obstruction. Results : Ninety‐two patients suspected of having intestinal obstruction were included. Correct diagnosis of intestinal obstruction was made in 21 cases (23%), and in 68 (74%) this diagnosis was excluded. Interpretation of the images on prospective analysis had sensitivity, positive predictive, specificity and negative predictive values of 100%, 87.5%, 95.8% and 100%, respectively. Clinical Significance : Ultrasonography is an excellent method for investigation of animals with gastrointestinal disorders, and is particularly useful for excluding obstructive processes.     

Cytotoxic Effects of Serum from Equine Grass Sickness Cases on Neuro-2a and PC12 Tet-Off Cell Lines: Implication for Using In Vitro Methods as Antemortem Diagnostic Tools

A wide variety of clinical and paraclinical methods have been used for diagnosis of equine grass sickness (EGS), but none of them could absolutely confirm the diagnosis, and postmortem pathologic examination is still considered the final step in precise diagnosis of EGS. Use of in vitro cell toxicity caused by EGS serum on neuronal cell lines was investigated. Three well-known cytotoxic methods were used to investigate the cytotoxicity of EGS serum on neuro-2a and genetically engineered PC12 Tet-Off P53 cells. The results of alamar blue reduction as an index for mitochondrial activities and intracellular adenosine triphosphate content assays, but not neutral red uptake, indicate that the EGS serum may affect the mitochondrial function and cellular metabolism at up to 60% of the cases. The results of present study might be used for diagnosis of EGS cases. Further studies with high sample size may lead us to uncover the pathogenesis of EGS and to increase the sensitivity and applicability of in vitro techniques as diagnostic tools.     

Fluorescence polarization assay for the diagnosis of bovine brucellosis: adaptation to field use

A fluorescence polarization assay (FPA) was used to test whole blood samples prepared by mixing blood cells from cattle without exposure to Brucella abortus (B. abortus) with sera from animals with confirmed (bacteriologically) infection. A cut-off value between negative and positive values was initially established to be 87.2mP. This value was changed to 95mP to increase assay specificity without loss of sensitivity when testing blood samples from negative animals. The FPA technology was applied to whole blood samples in the field and to stored whole blood samples using two diluent buffers. Relative sensitivity and specificity values for the FPA performed in the field, based on buffered antigen plate agglutination test and competitive enzyme immunoassay results were 95.3 and 97.3%, respectively. However, to obtain maximum sensitivity and specificity, a cut-off value of 105mP was determined for fresh whole blood samples. The relative sensitivity and specificity values of the FPA when testing stored whole blood samples were 100% each using a 95mP cut-off.The usefulness of the FPA for testing whole blood samples in the field was demonstrated.     

Evaluation of a broad range real-time polymerase chain reaction (RT-PCR) assay for the diagnosis of septic synovitis in horses

Septic synovitis is a potentially debilitating and life-threatening disorder in horses. We hypothesized that a universal bacterial real-time PCR (RT-PCR) assay would have improved sensitivity and decreased turn-around time for detection of bacteria in synovial fluid (SF) samples. Forty-eight SF samples were collected from 36 horses that presented to two referral institutions with suspected septic synovitis. Universal RT-PCR, bacterial culture and SF analysis were performed on all samples, and an interpretation on the sample being septic or not was derived by three board certified specialists from the history, clinical assessment and SF characteristics. RT-PCR results were compared to a composite standard comprised of positive culture and interpretation by all three specialists of samples as “septic”. For 41 of 48 samples (85%), culture and RT-PCR results were concordant. Compared to the composite standard, 83% of samples were correctly classified by RT-PCR (turn-around time of approximately 4 hours). Relative sensitivity and specificity of RT-PCR were 87% and 72% respectively, and 56% and 86% for culture. Hence, universal RT-PCR was a rapid and highly sensitive test, which may accelerate diagnosis and improve outcome for horses with septic synovitis.     

Correlation between fine-needle aspiration cytology and histopathology in the evaluation of cutaneous and subcutaneous masses from dogs and cats

BACKGROUND: Fine-needle aspiration cytology (FNAC) is commonly used as a diagnostic procedure to evaluate superficial and deep masses in animals. However, few studies have addressed the accuracy of FNAC in the evaluation of cutaneous and subcutaneous masses in a clinical setting. OBJECTIVE: The purpose of this study was to compare the accuracy of FNAC as compared with histopathology in the diagnosis of cutaneous and subcutaneous masses from dogs and cats. METHODS: Cytologic and histopathologic specimens obtained between 1999 and 2003 from 292 palpable cutaneous and subcutaneous masses obtained from 242 dogs and 50 cats were retrospectively evaluated. Cytologic samples were obtained by FNA and histopathologic samples were collected by surgical biopsy or at necropsy. Concordance was determined and the accuracy of FNAC for the diagnosis of neoplasia was determined using histopathology as the gold standard. RESULTS: Of 292 specimens, 49 (from 44 dogs and 5 cats) were excluded due to poor cellularity of the cytologic specimen (retrieval rate 83.2%, n = 243). A cytologic diagnosis of neoplasia was obtained in 176 cases (175 true positives and 1 false positive compared with histopathology). Sixty-seven cytology samples were classified as non-neoplastic (46 true negatives, 21 false negatives compared with histopathology). Overall, the cytologic diagnosis was in agreement with the histopathologic diagnosis in 90.9% (221/243) of cases. For diagnosing neoplasia, cytology had a sensitivity of 89.3%, a specificity of 97.9%, a positive predictive value of 99.4%, and a negative predictive value of 68.7%. CONCLUSIONS: The results of this study confirmed FNAC as a reliable and useful diagnostic procedure for the evaluation of palpable cutaneous and subcutaneous lesions in small animal practice.     

The suitability of ELISA for the detection of antibodies against Mycobacterium avium ssp. paratuberculosis in bulk milk samples from Rhineland-Palatinate

Paratuberculosis or Johne's Disease, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a notifiable disease in Germany which produces enormous economical losses in dairy farms. At present,there is no confirmed data about the actual number of infected livestock herds in Germany. A countrywide monitoring program to evaluate the prevalence in dairy herds would only be economically feasible on the basis of bulk milk testing. In this study, we evaluated two ELISA test kits (SVANOVIR Ptb-ELISA, IDEXX-M.pt. Milk test kit) for the detection of antibodies against MAP in bulk milk. First, the Paratuberculosis-status of the herd derived from the history of the farm was used as a gold standard. Paratuberculosis-negative farms were tested negative with each test, but paratuberculosis-positive or Paratuberculosis-serologically-positive farms were detected only in one case (Svanovir) or three cases (IDEXX), respectively. Even if inconclusive results are counted as positive, 82.9 % (Svanovir) or 80 % (IDEXX) of the paratuberculosis-positive or serologically paratuberculosis positive farms were not detected. Nevertheless, a re-validation of both ELISAs by means of ROC and TG-ROC analyses was attempted by searching for ideal cut-offs, optimised for bulk milk. If a high specificity was selected, no acceptable sensitivity could be reached.The best results were obtained using a sensitivity of 32.3 % at a specificity of 100 % (Svanovir). With a small change of the cut-off value, the sensitivity increased to still 57 %, but this reduced the specificity to 67 %. Similar results were obtained with the IDEXX-ELISA. We then evaluated the Svanovir-ELISA for the detection of bulk milk samples on the basis of the current paratuberculosis prevalence within 69 dairy herds from Rhineland-Palatinate using individual milk samples.When the bulk milk samples were tested in two different laboratories using the same ELISA, considerable differences in the results became evident. Nearly all samples were tested with a higher relative test result in one laboratory, which often led to differences in the classification of the prevalence levels.The estimated within-herd seroprevalences ranged between 0 % and 37 %.There was little agreement between the historical paratuberculosis herd status and the within-herd prevalence in milk serum, as reflected in a kappa-index of 0.146.To determine the sensitivity and specificity of the bulk milk ELISA by ROC and TG-ROC analysis, 116 bulk milk samples were used that had been obtained from the 69 dairy herds participating in the study. The optimal ratio of sensitivity (81 %) and specificity (77 %) relative to a "gold standard" was obtained when the cut-off was set at the 10 % level. These values for sensitivity and specificity were better than those obtained in an evaluation of the same ELISA in which the historical Paratuberculosis herd-status was used as a "gold standard." The results of this study question the suitability of the available ELISAs for bulk milk testing.Taking into account that the Svanovir-ELISA for individual milk samples has a sensitivity of 60 96% relative to the blood serum variant of the test, and that the latter has also a limited sensitivity due to the pathogenesis of paratuberculosis, the available test systems examined in this Study do not seem to be suitable for herd diagnosis by using bulk milk samples.     

Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti

Bovine besnoitiosis is an economically important disease in cattle caused by the protozoan parasite Besnoitia besnoiti, which occurs endemically in many countries of Africa and Asia and is spreading in Europe. Serological identification of subclinically infected cattle is important to avoid the introduction of infected animals into naive herds. Here we determine the sensitivity and specificity of the PrioCHECK^® Besnoitia Ab, a serological test recently introduced into the European market. Analytical specificity was examined using sera from animals experimentally infected with parasites related to B. besnoiti (n = 27). Three animals experimentally infected with Neospora caninum or Toxoplasma gondii showed inconclusive reactions in the ELISA (percent positivity relative to the positive control [PP] 10% ≤ 20%) while all other sera reacted negative (PP < 10%). An estimate of the diagnostic specificity was obtained by analysing field sera from bovine herds without besnoitiosis but with abortion problems associated to N. caninum (n = 403). The analysis revealed a specificity of 94.3% or 96.8% depending on the applied cut-off (PP 10% or 20%, respectively). Sensitivity was assessed with sera from 110 animals of a herd in Germany where clinical bovine besnoitiosis was first diagnosed in September 2008. A positive serological reference standard was defined regarding sera from animals as reference positive, if these animals had tested positive in at least two of a panel of three other serological tests (two different B. besnoiti immunoblots and one immunofluorescence antibody test) on both of two sampling dates, November 2008 and April 2009. A diagnostic sensitivity of 91.8% or 75.5% was determined for sera collected in November 2008 and a sensitivity of 82.7% or 50% for sera collected in April 2009 (cut-off PP 10% or PP 20%, respectively). The marked drop in sensitivity from November 2008 to April 2009 was predominantly observed in reference-positive cattle without clinical signs. We conclude that PrioCHECK^® Besnoitia Ab is a valuable diagnostic tool to detect clinically infected animals. Thus it may be used to support control measures, e.g., for the separation of infected animals from the remaining herd to avoid a further transmission of the infection within the herd.     

A comparative study of the intestinal microbiota of healthy horses and those suffering from equine grass sickness

This study compares quantitatively the microbiota of the gastrointestinal tract of healthy horses with that of horses with equine grass sickness (EGS). Faecal and ileal samples were cultured quantitatively on selective and non-selective media. Confirmed anaerobes were identified to species level.Overall faecal counts gave a ratio of aerobes:anaerobes of approximately 1:1. However, the mean counts in healthy horses of 4.4x10(8) aerobes:3.7x10(8) anaerobes per gram wet weight were different from counts in EGS (means were 10-100-fold higher), with statistically significant differences for the anaerobes (p=0.04). There were 10-100-fold more anaerobic cocci in EGS samples compared to healthy controls. Most of the seven species of anaerobic cocci were found in both healthy horses and EGS. Differences in clostridia isolated between health and disease were notable: fourteen species were isolated from EGS cases, compared to only one (C. bifermentans) in controls. The mean faecal clostridial counts in chronic disease were higher than in controls (10-fold) and in acute EGS (100-fold). In contrast, mean counts for ileal samples from acute cases, showed a 10-fold increase for clostridia compared to 1000-fold reduction in chronic cases (compared to faecal counts). Results indicate an increase in the bacterial numbers in the GI tract of animals with EGS compared to the controls and clostridia are prominent in EGS. Whether the increase in clostridia is the cause of GI stasis or a consequence remains uncertain.     

A comparison of gross pathology,histopathology, and mycobacterial culture for the diagnosis of tuberculosis in elk (Cervus elaphus).

Using the isolation of Mycobacterium bovis as the reference standard, this study evaluated the sensitivity, specificity and kappa statistic of gross pathology (abattoir postmortem inspection), histopathology, and parallel or series combinations of the two for the diagnosis of tuberculosis in 430 elk and red deer. Two histopathology interpretations were evaluated: histopathology I, where the presence of lesions compatible with tuberculosis was considered positive, and histopathology II, where lesions compatible with tuberculosis or a select group of additional possible diagnoses were considered positive. In the 73 animals from which M. bovis was isolated, gross lesions of tuberculosis were most often in the lung (48), the retropharyngeal lymph nodes (36), the mesenteric lymph node (35), and the mediastinal lymph nodes (16). Other mycobacterial isolates included: 11 M. paratuberculosis, 11 M. avium, and 28 rapidly growing species or M. terrae complex. The sensitivity estimates of gross pathology and histopathology I were 93% (95% confidence limits [CL] 84.97%) and 88% [CL 77.94%], respectively, and the specificity of both was 89% [CL 85.92%]). The sensitivity and specificity of histopathology II were 89% (CL 79.95%) and 77% (CL 72.81%), respectively. The highest sensitivity estimates (93-95% [CL 84.98%]) were obtained by interpreting gross pathology and histopathology in parallel (where an animal had to be positive on at least one of the two, to be classified as combination positive). The highest specificity estimates (94-95% [CL 91-97%] were generated when the two tests were interpreted in series (an animal had to be positive on both tests to be classified as combination positive). The presence of gross or microscopic lesions showed moderate to good agreement with the isolation of M. bovis (Kappa = 65-69%). The results showed that post-mortem inspection, histopathology and culture do not necessarily recognize the same infected animals and that the spectra of animals identified by the tests overlaps.     

Utility of 2 Immunological Tests for Antemortem Diagnosis of Equine Protozoal Myeloencephalitis (Sarcocystis neurona Infection) in Naturally Occurring Cases

Background: Antemortem diagnosis of equine protozoal myeloencephalitis (EPM) is challenging. Limited information is available regarding a commercial test (surface antigen 1 [SAG‐1] ELISA). Performance of another commercial test (indirect fluorescent antibody test [IFAT]) using samples from an independent group has not been well described. Hypothesis/Objectives: The primary goal was to evaluate the SAG‐1 ELISA and IFAT using naturally occurring EPM cases. A secondary goal was to obtain more information regarding clinical presentation. Animals: Hospital cases were admitted over 20 months and classified into 4 groups. Confirmed positive cases (n = 9) had asymmetric or multifocal neurologic deficits or both and postmortem lesions consistent with EPM. Confirmed negative cases (n = 17) had variable clinical signs and postmortem lesions consistent with another neurologic disease (or no lesions). Suspected positive cases (n = 10) had asymmetric or multifocal deficits or both, marked improvement after treatment for EPM, and other likely diseases excluded. Suspected negative cases (n = 29) had orthopedic disease and no neurologic deficits. Methods: Results of immunological testing (SAG‐1 ELISA and IFAT on serum or cerebrospinal fluid [CSF] or both), neurologic examinations, CSF analyses, and postmortem examinations were analyzed retrospectively. Results: SAG‐1 ELISA sensitivity was 12.5% (95% CI, 1.6–38.4) and specificity was 97.1% (95% CI, 84.7–99.9) using serum. IFAT sensitivity was 94.4% (95% CI, 72.7–99.9) and specificity was 85.2% (95% CI, 66.3–95.8) using serum; sensitivity was 92.3% (95% CI, 64.0–99.8) and specificity was 89.7% (95% CI, 72.7–97.8) using CSF. Conclusions and Clinical Importance: Low sensitivity of the SAG‐1 ELISA limited its usefulness for antemortem diagnosis of EPM in this patient population.     

Development and validation of an enzyme-linked immunosorbent assay for the diagnosis of porcine proliferative enteropathy.

The objective of this study was to develop an indirect enzyme-linked immunosorbent assay (ELISA) using a sonicated pure culture of Lawsonia intracellularis as the antigen (So-ELISA). A total of 332 serum samples, consisting of 232 experimentally infected animals and 100 animals naturally infected with L. intracellularis, were used to assess the diagnostic sensitivity. Three hundred and fifty-five sera from uninfected animals were used to determine the diagnostic specificity. The receiver operating characteristic and mean +3 standard deviation of optical density (OD) values from uninfected animals were used for selecting cut-off points. The diagnostic accuracy of So-ELISA was considered to be high as the area under the curve index was 0.991 with 0.0029 standard error. The optimal cut-off for So-ELISA was set at 0.45 OD with 89.8% sensitivity and 99.4% specificity based on a combination of good sensitivity and high specificity. No cross-reactivity was found in sera from pigs exposed to Brachyspira pilosicoli, B. hyodysenteriae, Campylobacter mucosalis, C. jejuni, or C. coli. Inter- and intracoefficient of variation of all control sera tested with So-ELISA was less than 10%. The observed agreements between So-ELISA and the immunoperoxidase monolayer assay tested with experimental challenge animals and field samples were 95.08% with 0.88 kappa and 90.65% with 0.74 kappa value, respectively. So-ELISA was able to detect the seroconversion of infected animals at 2 to 4 weeks after exposure to L. intracellularis. Based on the validation results, So-ELISA could be used as an alternative serology for proliferative enteropathy diagnosis.