Neuropathology and diagnostics in food animals

Diseases of the central nervous system are relatively common in food animals. Potential causes include infectious agents, nutritional deficiencies, metabolic disorders, genetic defects, toxins, and idiopathic causes. Food animals are frequently raised in large groups, there is often human and animal traffic between groups, and large numbers of animals are often fed the same ration. This makes it important to obtain an accurate etiological diagnosis as soon as possible so that treatment can be initiated and to limit the spread of infectious agents and toxins. In all disease situations, an antemortem diagnosis is preferable to a postmortem one because it allows for possible treatment of affected individuals, but that is not always possible and determining the correct etiologic diagnosis often depends on a thorough postmortem examination and collection of samples. Critical components for obtaining a successful diagnosis are as complete a history as possible, a thorough examination of affected and unaffected animals and their surroundings, a thorough necropsy and collection of the appropriate diagnostic samples, and accurate interpretation of the findings. The goals of this article are to review some of the steps and procedures necessary to collect the necessary information, to briefly describe a few techniques for examination of the central nervous system, and to review the gross pathology of conditions likely to be encountered in a food animal practice

Porcine reproductive and respiratory syndrome: characteristic features of the infected fetus

Pregnant gilts were infected at 90 days of gestation with porcine reproductive and respiratory virus (PRRSV) isolate SD-23983. Fetuses recovered between 109 and 112 days of gestation were analyzed for the presence of PRRSV. The results showed that not all fetuses were infected, and that infected fetuses tended to be clustered within the uterine horns, suggesting that virus is spread from fetus to fetus. Even though affected litters exhibited different degrees of gross pathology, the presence of an anatomical abnormality was not an identifier of an infected fetus. Analysis of virus replication in individual tissues identified the thymus as the principal site of PRRSV replication. The results show that PRRSV infection in the developing fetus follows a unique course and that PRRSVinduced alterations may be the result of the effect of PRRSV on maternal tissues. These factors need to be taken into consideration when diagnosing PRRSV infection as the cause for aborted and stillborn fetuses.; Swine Day, 2005, Kansas State University, Manhattan, KS, 200

Investigation of a Microcystis aeruginosa cyanobacterial freshwater harmful algal bloom associated with acute microcystin toxicosis in a dog

Microcystin poisoning was diagnosed in a dog exposed to a Microcystis aeruginosa dominated freshwater harmful algal bloom at Milford Lake, Kansas, which occurred during the summer of 2011. Lake water microcystin concentrations were determined at intervals during the summer, using competitive enzyme-linked immunosorbent assays, and indicated extremely high, localized microcystin concentrations of up to 126,000 ng/ml. Multiple extraction and analysis techniques were utilized in the determination of free and total microcystins in vomitus and liver samples from the poisoned dog. Vomitus and liver contained microcystins, as determined by enzyme-linked immunosorbent assays, and the presence of microcystin LR was confirmed in vomitus and liver samples using liquid chromatography coupled with tandem mass spectrometry. Major toxic effects in a dog presented for treatment on the day following exposure included fulminant liver failure and coagulopathy. The patient deteriorated rapidly in spite of aggressive treatment, and was euthanized. Postmortem lesions included diffuse, acute, massive hepatic necrosis and hemorrhage, and acute necrosis of the renal tubular epithelium. A diagnosis of microcystin poisoning was based on the demonstration of M. aeruginosa and microcystin-LR in the lake water, as well as in vomitus produced early in the course of the poisoning, the presence of microcystin-LR in liver tissue, and on a typical clinical course

Effects of adding cracked corn to a pelleted supplement for nursery and finishing pigs

Three experiments were conducted to determine the effects of supplementing cracked corn into diets of nursery and finishing pigs. In Exp. 1, 144 pigs were used in a 28-d trial. Pigs (PIC TR4 × 1050; initially 16.5 lb) were weaned and allotted with 6 pigs per pen (3 barrows and 3 gilts) and 6 pens per treatment. All pigs were fed a common diet for 7 d postweaning and the experimental diets for the next 28 d. Treatments were corn-soybean meal-based in the form of mash, pellets, and pellets with 100% of the corn either ground (618 μm) or cracked (3,444 μm) and blended into the diet after the rest of the formulation (the supplement) had been pelleted. Overall (d 0 to 28), ADG and F/G improved when pigs were fed the mash control compared to the pelleted diets (P \u3c 0.001); however, this response was caused by the poor performance of pigs fed the supplement treatments, with the pigs fed the complete pellets having improved (P \u3c 0.01) ADG and F/G compared with pigs fed the pelleted supplement blended with ground and cracked corn. Finally, pigs fed the supplement blended with cracked corn had numerically lower (P \u3c 0.11) ADG and poorer (P \u3c 0.001) F/G compared to those fed the supplement blended with ground corn. In Exp. 2, 224 nursery pigs (initially 16.3 lb) were used with 7 barrows or 7 gilts per pen and 8 pens per treatment. Treatments were corn-soybean meal-based and fed as mash, pellets, and pellets with 50% of the corn either ground (445 μm) or cracked (2,142 μm) and blended with the pelleted supplement. Pigs fed mash had improved (P \u3c 0.03) ADG and F/G compared with pigs fed the other treatments; however, this resulted from adding ground or cracked corn outside the pellets (complete pellets vs. pelleted supplement with corn, P \u3c 0.01). In Exp. 3, 252 finishing pigs (initially 88.2 lb) were used with 7 pigs per pen and 9 pens per treatment. The treatments were the same as Exp. 2. Pigs fed mash had lower (P \u3c 0.004) ADG compared with pigs fed diets with pellets. Pigs fed complete pellets had improved (P \u3c 0.03) ADG and F/G compared with pigs fed corn and the pelleted supplement. Also, pigs fed the supplement blended with cracked corn had greater (P \u3c 0.02) ADG than pigs fed the supplement blended with ground corn. Pelleting the diet led to an increase (P \u3c 0.05) in ulceration scores; however, these negative effects on ulcer scores were reduced (P \u3c 0.001) by cracking 50% of the corn and adding it postpellet.; Swine Day, Manhattan, KS, November 17, 201

Pigs immunized with a novel E2 subunit vaccine are protected from subgenotype heterologous classical swine fever virus challenge

Citation: Madera, R., Gong, W. J., Wang, L. H., Burakova, Y., Lleellish, K., Galliher-Beckley, A., . . . Shi, J. S. (2016). Pigs immunized with a novel E2 subunit vaccine are protected from subgenotype heterologous classical swine fever virus challenge. Bmc Veterinary Research, 12, 10. https://doi.org/10.1186/s12917-016-0823-4Background: Classical swine fever (CSF) or hog cholera is a highly contagious swine viral disease. CSF endemic countries have to use routine vaccination with modified live virus (MLV) vaccines to prevent and control CSF. However, it is impossible to serologically differentiate MLV vaccinated pigs from those infected with CSF virus (CSFV). The aim of this study is to develop a one-dose E2-subunit vaccine that can provide protection against CSFV challenge. We hypothesize that a vaccine consisting of a suitable adjuvant and recombinant E2 with natural conformation may induce a similar level of protection as the MLV vaccine. Results: Our experimental vaccine KNB-E2 was formulated with the recombinant E2 protein (Genotype 1.1) expressed by insect cells and an oil-in-water emulsion based adjuvant. 10 pigs (3 weeks old, 5 pigs/group) were immunized intramuscularly with one dose or two doses (3 weeks apart) KNB-E2, and 10 more control pigs were administered normal saline solution only. Two weeks after the second vaccination, all KNB-E2 vaccinated pigs and 5 control pigs were challenged with 5 x 10(5) TCID50 CSFV Honduras/1997 (Genotype 1.3, 1 ml intramuscular, 1 ml intranasal). It was found that while control pigs infected with CSFV stopped growing and developed high fever (>40 degrees C), high level CSFV load in blood and nasal fluid, and severe leukopenia 3-14 days post challenge, all KNB-E2 vaccinated pigs continued to grow as control pigs without CSFV exposure, did not show any fever, had low or undetectable level of CSFV in blood and nasal fluid. At the time of CSFV challenge, only pigs immunized with KNB-E2 developed high levels of E2-specific antibodies and anti-CSFV neutralizing antibodies. Conclusions: Our studies provide direct evidence that pigs immunized with one dose KNB-E2 can be protected clinically from CSFV challenge. This protection is likely mediated by high levels of E2-specific and anti-CSFV neutralizing antibodies

Comparison of host immune responses to homologous and heterologous type II porcine reproductive and respiratory syndrome virus (PRRSV) challenge in vaccinated and unvaccinated pigs

Porcine reproductive and respiratory syndrome (PRRS) is a high-consequence animal disease with current vaccines providing limited protection from infection due to the high degree of genetic variation of field PRRS virus. Therefore, understanding host immune responses elicited by different PRRSV strains will facilitate the development of more effective vaccines. Using IngelVac modified live PRRSV vaccine (MLV), its parental strain VR-2332, and the heterologous KS-06-72109 strain (a Kansas isolate of PRRSV), we compared immune responses induced by vaccination and/or PRRSV infection. Our results showed that MLV can provide complete protection from homologous virus (VR-2332) and partial protection from heterologous (KS-06) challenge. The protection was associated with the levels of PRRSV neutralizing antibodies at the time of challenge, with vaccinated pigs having higher titers to VR-2332 compared to KS-06 strain. Challenge strain did not alter the cytokine expression profiles in the serum of vaccinated pigs or subpopulations of T cells. However, higher frequencies of IFN-γ-secreting PBMCs were generated from pigs challenged with heterologous PRRSV in a recall response when PBMCs were re-stimulated with PRRSV. Thus, this study indicates that serum neutralizing antibody titers are associated with PRRSV vaccination-induced protection against homologous and heterologous challenge

Prevalence of Mycoplasma bovis in bovine pneumonia and arthritis

Samples from cattle with pneumonia and/or arthritis were cultured for Mycoplasma. When requested, the Mycoplasma isolates were further identified to species by polymerase chain reaction or restriction fragment length polymorphism. The records of all cases where mycoplasma testing was performed were examined and other infectious agents known to cause pneumonia or arthritis were recorded. Mycoplasma species were isolated from 85% of the lung samples and 69% of the joint samples. Eighty-four percent of the 81 Mycoplasma isolates that were further identified were M. bovis, which clearly made it the most common pathogenic agent identified in samples from cattle with pneumonia and/or arthritis. M. bovis appeared to play an important role in feedlot pneumonia and was the most common cause of arthritis. Unfortunately, treatment and prevention options are currently either ineffective or their effectiveness is unknown

Pilus genes in Escherichia coli isolated from pigs with diarrhea

A retrospective survey of the Kansas State Veterinary Diagnostic Laboratory records was made for Escherichia coli isolated from pigs with diarrhea. There were 111 E. coli isolates that carried genes for attachment pili that are necessary for E. coli to cause diarrhea. Of the 111 isolates, 103 had one pilus gene and eight had two pilus genes. The most common pilus type was the K88 pilus accounting for 73% of the isolates. All but one of the K88 isolates also carried at least one toxin gene indicating that they were virulent for pigs. The next most common pilus type was F18 accounting for 21% of the isolates. However, more than half of the F18 isolates did not have detectable toxin genes. F41, K99, and 987P pilus types made up 7%, 4%, and 2% of the isolates, respectively (percentages total greater than 100% because some isolates had 2 pilus genes). Escherichia coli expressing pilus types K88 and F41 are currently the major causes of colibacillosis in pigs

Porcine reproductive and respiratory syndrome: characteristic features of the infected fetus

Swine research, 2005 is known as Swine day, 2005Pregnant gilts were infected at 90 days of gestation with porcine reproductive and respiratory virus (PRRSV) isolate SD-23983. Fetuses recovered between 109 and 112 days of gestation were analyzed for the presence of PRRSV. The results showed that not all fetuses were infected, and that infected fetuses tended to be clustered within the uterine horns, suggesting that virus is spread from fetus to fetus. Even though affected litters exhibited different degrees of gross pathology, the presence of an anatomical abnormality was not an identifier of an infected fetus. Analysis of virus replication in individual tissues identified the thymus as the principal site of PRRSV replication. The results show that PRRSV infection in the developing fetus follows a unique course and that PRRSVinduced alterations may be the result of the effect of PRRSV on maternal tissues. These factors need to be taken into consideration when diagnosing PRRSV infection as the cause for aborted and stillborn fetuses

Effects of bioplus 2B and Levucell SB on weanling pig growth performance and fecal shedding in response to oral challenge with salmonella serovar typhimurium

Eighty-five pigs (initially 12.9 lb and 15 ±1 d of age) were used in two 28-d trials to determine the effects of the probiotics BioPlus 2B (a bacillus-based product from Chr. Hansen BioSystems), a source of Bacillus subtilis and Bacillus licheniformis, and Levucell SB (an active dry yeast product from Lallemand Animal Nutrition), a yeast (Saccharomyces cerevisiae) product that is a source of mannanoligosaccharides on growth and performance of Salmonella enterica serovar Typhimurium shedding in a young growing pig model. Pigs were fed one of five dietary treatments: 1) A control diet containing no probiotics or antibiotics; 2) the control diet with carbadox (50 g/ton); 3) the control diet with Bio-Plus 2B (0.05% of the diet); 4) the control diet with Levucell SB (100 g/ton); 5) the control diet with Bioplus 2B (0.05% of the diet) and Levucell SB (100 g/ton). Diets did not contain growth promoting levels of zinc oxide or copper sulfate. Significant differences in the two trials were seen, with the second trial having 0.1 lb/d greater growth and .18 lb/d greater feed intake than the first trial. In trial 1, pigs fed the control diet and Bioplus 2B had greater gains and feed intakes (P0.10) between diets. Results indicate that within an environment where enteric disease may be active, BioPlus 2B and Levucell SB may provide growth enhancement over a diet devoid of antimicrobials