Vacunación de coccidiosis aviar

La coccidiosis es la enfermedad parasitaria más importante en la producción avícola, y como tal se ha ido buscando distintas formas de combatirla. Primero fueron los coccidiostáticos añadidos al pienso, pero con la aparición de las resistencias se tuvo que sustituir por el estudio e implantación de distintas vacunas. De esta manera se han ido desarrollando distintas formas de profilaxis a medida que iba evolucionando la ciencia y los estudios realizados. Primero se intentó con cepas patógenas, forma de vacunación que quedó relegada debido al gran riesgo de aparición de signos clínicos y la necesidad de utilizar coccidiostáticos. La forma de vacunación que se ha quedado como predominante es la de cepas atenuadas por precocidad. Basada en seleccionar durante varias generaciones los primeros ooquistes expulsados. De esta forma se disminuye el tamaño de la esquizogonia por el menor número de merozoitos. Y a su vez disminuye el periodo de prepatencia y patogenicidad con respecto a la cepa original. Estas vacunas disponen de una característica primordial como es que son genéticamente estables. Otro tipo vacunal que se probó posteriormente es la protección por inmunidad maternal; de esta forma se pretendía que protegiendo a las madres, los pollitos estuvieran protegidos los primeros días de vida y luego su propio sistema inmune fuera el que se hiciera resistente contra las especies de Eimeria. No ha terminado de funcionar porque esta forma de vacunar puede ser útil para granjas extremadamente controladas sanitariamente, pero demasiado peligroso para la mayoría de explotaciones avícolas. Por último, también se ha probado, sin éxito, la atenuación de las cepas en embrión de pollo. Y aunque experimentalmente se consigue que las cepas pierdan parte de su patogenicidad, tienen el grave problema de que no son estables genéticamente y por tanto puede revertir la atenuación

IL-17A regulates Eimeria tenella schizont maturation and migration in avian coccidiosis

Although IL17A is associated with the immunological control of various infectious diseases, its role in host response to Eimeria infections is not well understood. In an effort to better dissect the role of IL17A in host-pathogen interactions in avian coccidiosis, a neutralizing antibody (Ab) to chicken IL17A was used to counteract IL17A bioactivity in vivo. Chickens infected with Eimeria tenella and treated intravenously with IL17A Ab, exhibited reduced intracellular schizont and merozoite development, diminished lesion score, compared with untreated controls. Immunohistological evaluation of cecal lesions in the parasitized tissues indicated reduced migration and maturation of second-generation schizonts and reduced lesions in lamina propria and submucosa. In contrast, untreated and infected chickens had epithelial cells harboring second-generation schizonts, which extend into the submucosa through muscularis mucosa disruptions, maturing into second generation merozoites. Furthermore, IL17A Ab treatment was associated with increased parameters of Th1 immunity (IL2- and IFN¿- producing cells), reduced levels of reactive oxygen species (ROS), and diminished levels of serum matrix metalloproteinase-9 (MMP-9). Finally, schizonts from untreated and infected chickens expressed S100, Wiskott-Aldrich syndrome protein family member 3 (WASF3), and heat shock protein-70 (HSP70) proteins as merozoites matured, whereas the expression of these proteins was absent in IL17A Ab-treated chickens. These results provide the first evidence that the administration of an IL17A neutralizing Ab to E. tenella-infected chickens inhibits the migration of parasitized epithelial cells, markedly reduces the production of ROS and MMP-9, and decreases cecal lesions, suggesting that IL17A might be a potential therapeutic target for coccidiosis control

Raíces y alas: recuerdos y ficciones

El segundo número de la colección Laboratorio Transmedia (ISSN: 2794-0861) contiene 36 relatos escritos durante el curso 2021/2022 por estudiantes de la Universidad para Mayores

Myofibroblasts and myoepithelial cells in the chicken Harderian gland

An electron microscopic study of the myoepithelial cells in the chicken Harderian gland provides evidence that these cells can be transformed into myofibroblasts. After the application of a Brucella ovis suspension in sterile saline onto the eyeball, every 5 minutes for half an hour, myoepithelial cells gradually develop over a 90-minute period the characteristic features of myofibroblasts: bundles of intracytoplasmic microfilament; abundant rough endoplasmic reticulum; prominent Golgi complex; and surface membrane differentiations, that provide attachment to neighbouring epithelial cells. No typical desmosomes are observed. Besides, the intercellular space between epithelial cells and myofibroblasts increases and the basement membrane adjacent to myofibroblasts disappears. Hypoxia is hypothesized to be involved in the transformation of myoepithelial cells into myofibroblasts

Immune complex-mediated glomerulopathy in Barbus graellsi infected with Myxobolus Spp

Membranous glomerulonephritis caused in Barbus graellsi by myxosporidian infections have been studied by electron microscopy and immunoelectron microscopy techniques. This study indicates that Myxosporidian infection produces a chronic severe aggression. Spores reach the spleen, the kidney and the liver, where they are trapped and phagocyted by Melano Macrophage Centres. Consequently, the commencement of a immunological response to myxosporidian is evident. Our results show the presence of immunodeposits in the basement membrane of the glomeruli, suggesting that they might initiate glomerulonephritis. The lesion was markedly similar to immune complex-mediated glomerulonephritis disease in higher vertebrates

Efficacy of Two Peroxygen-Based Disinfectants for Inactivation of Cryptosporidium parvum Oocysts

Two commercial peroxygen-based disinfectants containing hydrogen peroxide plus either peracetic acid (Ox-Virin) or silver nitrate (Ox-Agua) were tested for their ability to inactivate Cryptosporidium parvum oocysts. Oocysts were obtained from naturally infected goat kids and exposed to concentrations of 2, 5, and 10% Ox-Virin or 1, 3, and 5% Ox-Agua for 30, 60, and 120 min. In vitro excystation, vital dyes (4′,6′-diamidino-2-phenylindole and propidium iodide), and infectivity in neonatal BALB/c mice were used to assess the viability and infectivity of control and disinfectant-treated oocysts. Both disinfectants had a deleterious effect on the survival of C. parvum oocysts, since disinfection significantly reduced and in some cases eliminated their viability and infectivity. When in vitro assays were compared with an infectivity assay as indicators of oocyst inactivation, the excystation assay showed 98.6% inactivation after treatment with 10% Ox-Virin for 60 min, while the vital-dye assay showed 95.2% inactivation and the infectivity assay revealed 100% inactivation. Treatment with 3% Ox-Agua for 30 min completely eliminated oocyst infectivity for mice, although we were able to observe only 74.7% inactivation as measured by excystation assays and 24.3% with vital dyes (which proved to be the least reliable method for predicting C. parvum oocyst viability). These findings indicate the potential efficacy of both disinfectants for C. parvum oocysts in agricultural settings where soil, housing, or tools might be contaminated and support the argument that in comparison to the animal infectivity assay, vital-dye and excystation methods overestimate the viability of oocysts following chemical disinfection

Cryptosporidium Genotypes and Subtypes in Lambs and Goat Kids in Spain▿

To provide information on the transmission dynamics of cryptosporidial infections in domestic small ruminants and the potential role of sheep and goats as a source for human cryptosporidiosis, Cryptosporidium-positive isolates from 137 diarrheic lambs and 17 goat kids younger than 21 days of age were examined by using genotyping and subtyping techniques. Fecal specimens were collected between 2004 and 2006 from 71 sheep and 7 goat farms distributed throughout Aragón (northeastern Spain). Cryptosporidium parvum was the only species identified by restriction analyses of PCR products from small-subunit rRNA genes from all 154 microscopy-positive isolates and the sequencing of a subset of 50 isolates. Sequence analyses of the glycoprotein (GP60) gene revealed extensive genetic diversity within the C. parvum strains in a limited geographical area, in which the isolates from lambs exhibited 11 subtypes in two subtype families (IId and IIa) and those from goat kids displayed four subtypes within the family IId. Most isolates (98%) belonged to the subtype family IId, whereas only three isolates belonged to the most widely distributed family, IIa. Three of the four most prevalent subtypes (IIdA17G1a, IIdA19G1, and IIdA18G1) were previously identified in humans, and five subtypes (IIdA14G1, IIdA15G1, IIdA24G1, IIdA25G1, and IIdA26G1) were novel subtypes. All IId subtypes were identical to each other in the nonrepeat region, except for subtypes IIdA17G1b and IIdA22G1, which differed by a single nucleotide polymorphism downstream of the trinucleotide repeats. These findings suggest that lambs and goat kids are an important reservoir of the zoonotic C. parvum subtype family IId for humans

Comparison of control methods for coccidiosis in native Spanish "Castellana Negra" chickens

Coccidiosis is a disease responsible for serious economic losses in the poultry industry. This paper compares the effect of coccidiosis infection in a population of experimentally infected Castellana Negra chickens previously administered the ionophorous antibiotic monensin (Treatment 1), Alquernat Zyox®, a herb-based product (Treatment 2), or a live vaccine based on oocystes selected for precocity (Treatment 3). Fifty birds per treatment were housed in captivity and weighed individually once every two weeks. At nine weeks they were infected with pathogenic oocysts of Eimeria tenella, E. acervulina and E. maxima. No significant differences (P<0.05) were seen in body weight between the birds in the three treatment groups after week 10. The average daily weight gain of the Alquernat Zycox®-treated and vaccinated birds was similar over the entire experimental period, and more regular than that of the monensin-treated birds. The number of oocysts eliminated in the faeces and the degree of intestinal injury caused were analysed at 10, 11 and 12 weeks. The vaccine-treated birds shed a smaller number of oocysts in their faeces at 11 and 12 weeks than did those treated with monensin or Alquernat Zycox® (P<0.001). At 11 and 12 weeks the vaccine- and Alquernat Zycox®-treated birds showed significantly (P<0.05) less intestinal injury than the monensin-treated birds.La coccidiosis es una parasitosis con gran incidencia económica en la industria avícola. En el presente trabajo se comparan los efectos tras la infección experimental por coccidios en una población de pollos de raza Castellana Negra, utilizando el antibiótico ionóforo monensina (Tratamiento 1), un producto natural como es Alquernat Zycox® (Tratamiento 2) y una vacuna de ooquistes atenuados por precocidad (Tratamiento 3). Un total de 50 aves por grupo se alojaron en parques en cautividad, las cuales se pesaron individualmente cada 2 semanas. A las 9 semanas se infectaron experimentalmente con ooquistes patógenos de Eimeria tenella, E. acervulina y E. maxima. No hubo diferencias significativas entre el peso corporal de los pollos de los distintos grupos en la semana 10. La ganancia media de peso diario de los pollos tratados con Alquernat Zycox® y los vacunados fueron similares durante todo el periodo experimental. Es más, su crecimiento fue más regular que el de los pollos tratados con monensina. A las 10, 11 y 12 semanas se analizó el número de ooquistes eliminados en las heces y el grado de lesiones intestinales. Las aves vacunadas eliminaron una cantidad inferior de ooquistes que las tratadas con monensina y también presentaron menor número de ooquistes en las heces a las 11 y 12 semanas postinfección que los tratados con Alquernat Zycox® (P<0,001). El grado de lesiones a las 11 y 12 semanas fue significativamente inferior (P<0,05) en las tratadas con la vacuna y con Alquernat Zycox® que en las tratadas con monensina

Intra-Species Genetic Diversity and Clonal Structure of <i>Cryptosporidium parvum</i> in Sheep Farms in a Confined Geographical Area in Northeastern Spain

<div><p>A multilocus fragment typing approach including eleven variable-number tandem-repeat (VNTR) loci and the GP60 gene was used to investigate the intra-farm and intra-host genetic diversity of <i>Cryptosporidium parvum</i> in sheep farms in a confined area in northeastern Spain. Genomic DNA samples of 113 <i>C</i>. <i>parvum</i> isolates from diarrheic pre-weaned lambs collected in 49 meat-type sheep farms were analyzed. Loci exhibited various degrees of polymorphism, the finding of 7–9 alleles in the four most variable and discriminatory markers (ML2, Cgd6_5400, Cgd6_3940, and GP60) being remarkable. The combination of alleles at the twelve loci identified a total of 74 multilocus subtypes (MLTs) and provided a Hunter-Gaston discriminatory index of 0.988 (95% CI, 0.979−0.996). The finding that most MLTs (n = 64) were unique to individual farms evidenced that cryptosporidial infection is mainly transmitted within sheep flocks, with herd-to-herd transmission playing a secondary role. Limited intra- host variability was found, since only five isolates were genotypically mixed. In contrast, a significant intra-farm genetic diversity was seen, with the presence of multiple MLTs on more than a half of the farms (28/46), suggesting frequent mutations or genetic exchange through recombination. Comparison with a previous study in calves in northern Spain using the same 12-loci typing approach showed differences in the identity of major alleles at most loci, with a single MLT being shared between lambs and calves. Analysis of evolutionary descent by the algorithm eBURST indicated a high degree of genetic divergence, with over 41% MLTs appearing as singletons along with a high number of clonal complexes, most of them linking only two MLTs. Bayesian Structure analysis and <i>F</i> statistics also revealed the genetic remoteness of most <i>C</i>. <i>parvum</i> isolates and no ancestral population size was chosen. Linkage analysis evidenced a prevalent pattern of clonality within the parasite population.</p></div

Single-locus variant eBURST network for 70 multilocus subtypes (MLTs) identified among <i>Cryptosporidium parvum</i> isolates from calves.

<p>Dots represent MLTs, with diameters proportional to numbers of isolates. Single locus variants are joined by lines. Distance between dots is random and does not provide additional information. The allelic profile of each MLT is indicated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0148811#pone.0148811.t003" target="_blank">Table 3</a>.</p