No abstract

Background Marajó Island, within in the Amazon River Delta, supports numerous bands of feral equids including the genetically distinct Marajoara horses. Approximately 40% of the equids on the island are infected with Equine infectious anemia virus (EIAV). This high seropositivity rate coupled with the need to preserve rare breeds such as the Marajoara horse precludes euthanasia as the primary means for controlling EIAV in this region. In the absence of iatrogenic transmission, spread of this lentivirus is mediated primarily by hematophagous insects, whose year-round prevalence on the island is supported by favorable climatic conditions. In addition, cases of vertical EIAV transmission have been observed suggesting inclusion of seropositive mares in restorative breeding programs could result in their progeny becoming infected with this virus either pre-parturition or post-partum via hematophagous insects. Therefore, the aim of this study was to evaluate EIAV vertical and post-partum insect-mediated transmission rates among foals born to seropositive feral mares until natural weaning. Serum samples from foals born to seropositive feral mares within the Soure municipality, of Marajó Island, were collected to investigate their serological status, using an indirect ELISApgp45, with positive samples confirmed using the classical agar gel immunodiffusion (AGID) assay. Results The serological status of 28 foals were monitored over a 2-year period with some subjects, depending on their date of birth, being sampled up to six times. All foals remained with their respective mares until fully weaned at approximately 10 months of age. Only 2 foals (7.14%) in the study group became seropositive against EIAV. Conclusion The results demonstrate that in most cases it is possible to obtain seronegative foals born to and eventually weaned by EIA positive mares, even in equatorial regions where substantial rainfall and high temperatures favor the proliferation of insect vectors.

Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ) and Puruca (MP) horses. Primary epidermal lamella (PEL) and secondary epidermal lamella (SEL) were measured (length and width) in several regions, and their shapes were morphologically classified into different types. Breed groups were compared using analysis of variance, followed by Tukey or Dunn tests (P<0.05). Early signs of laminitis such as abnormal keratinization of the abaxial primary dermal lamella, tapered tips of the axial PELs, pointed tips of the SEL, nuclei condensation, and abnormal spatial orientation of the secondary epidermal basal cells (SELBC), were seen only in MM horses. MP horses had a greater interface of epidermis/dermis contact than MJ horses and more rounded nuclei in the round SELBC than MM horses. In agreement with the study hypothesis, semi-feral MJ and MP horses’ lamellae were classified as healthier than MM horses, which showed early signs of endocrinopathic laminitis.

Background Marajó Island within in the Amazon River Delta supports numerous bands of feral equids including the genetically distinct Marajoara horses. Roughly 40% of the equids on the island are infected with the Equine infectious anemia virus (EIAV). In the absence of iatrogenic transmission, spread of this lentivirus is mediated mainly by hematophagous insects whose year-round prevalence on the island is supported by favorable climatic conditions. The euthanasia of all infected equids within the population is not a feasible strategy when the prevalence of the disease is high or in highly specialized or rare breeds of equid such as the Marajoara horse. Preservation of these animals is complicated by high rates of seropositivity with the potential for vertical transmission or insect mediated transmission following parturition of foal. Therefore, the aim of this study was to evaluate EIAV vertical and post-partum insect-mediated transmission rates among foals born to seropositive feral mares until natural weaning. Serum samples of foals born to seropositive feral mares from Soure municipality, within Marajó Island, were collected to investigate their serological status, using an indirect ELISApgp45 with positive samples being tested in the classical agar gel immunodiffusion (AGID) assay to confirm the results. Results Twenty-eight foals were sampled and their serological status was monitored over a 2-year period. Depending on the birth date, some of them were sampled up to six times. All foals remained with their respective mares until fully weaned, approximately 10 months of age, and just 2 of 28 foals (7.14%) in the study group became seropositive against EIAV. Conclusion The results showed that in most cases it is possible to obtain negative foals born to and eventually weaned by EIA positive mares, even in equatorial regions where substantial rainfall and high temperatures favor the proliferation of insect vectors.

Pela primeira vez no. estado do Pará. foi diagnosticada pelos métodos anátomo e histopatológicos um caso de 'infossarcoma bovina esporádica em um bezerro da raça Si mental, macho, com três meses de idade pertencente a um ebanho altamente infectado pelo vírus da leucose enzoótica bovina (LEB). A necropsia revelou hipertrofia dos linfonodos region;;lis, esplenomegalia, hepatomegalia e formações tu morais nos rins. Histologicamente observou-se nas vísceras alteradas uma proliferação tu moral com células pequenas e grandes da série linfocitária e com índice mitótico 1,1; 1 ,4; 1 ,5, conforme a Working Formulation of National Cancer lnstitute (Vernidor et. ai., 1992), no fígado, baço e rim, respectivamente. No fígado ainda foi encontrada uma grave degeneração gordurosa, como conseqüência dos distúrbios circulatórios causados pela infiltração tu moral a nível de sinusóides. Conforme a classificação patológica, o caso pode ser considerado como "linfossarcoma difuso e misto de pequenas e grandes células". Palavras-chave: leucose bovina; tipo bezerro de leucose esporádica; Simental, histopatologia. O termo leucoseé uma denominação geral para as doenças do sistema hematopoietico caracterizadas por proliferação tumoral de leucocitos. Divide-se esta proliferação desfreada e desordenada em duas formas básicas: a leucemia e o linfoma.