Recent Progress on Epidemiology and Pathobiology of Porcine Circovirus 3

The recently discovered porcine circovirus 3 (PCV3) belongs to the Circovirus genus of the Circoviridae family together with the other three PCVs, PCV1, PCV2, and PCV4. As reported, PCV3 can infect pig, wild boar, and several other intermediate hosts, resulting in single or multiple infections in the affected animal. The PCV3 infection can lead to respiratory diseases, digestive disorders, reproductive disorders, multisystemic inflammation, and immune responses. Up to now, PCV3 infection, as well as the disease caused by PCV3, has been reported in many swine farms worldwide with high positive rates, which indicates that the virus may be another important pathogen in the swine industry. Therefore, we reviewed the current progress on epidemiology and pathobiology of PCV3, which may provide the latest knowledge of the virus and PCV3-related diseases.

Diagnóstico de ectima contagioso em pequenos ruminantes através da Reação em Cadeia da Polimerase em Tempo Real

The virus of contagious ecthyma (CEV), also known as orf virus (ORFV) is the etiological agent of contagious ecthyma (CE) in sheep and goat and belongs to the Parapoxvirus genus, family Poxviridae. In some cases, CE can be confused with vesicular diseases so there is need for differentiation especially because, according to the standards of the National Program for the Eradication of FMD (PNEFA), goats and sheep are not vaccinated against Foot and Mouth Disease (FMD), acting as sentinel animals. Although initial studies have demonstrated the usefulness of the polymerase chain reaction (PCR) as a diagnostic test, there are no studies involving its use on Brazilian field samples, which may be genetically distinct from previously studied samples, as described in a study of restriction sites analysis of Brazilian CE samples. This work was conducted with the goal of standardizing a PCR (qPCR) test using SYBR Green I dye for molecular diagnosis of EC in DNA extracted from lesions of affected animal or cell culture inoculated in field samples. The products were detected with qPCR dissociation curve analysis which showed a peak at 88 ºC indicating that positive samples have only one specific amplification product. All DNA samples tested (29 animals crusts and their cell cultures) were positive in the qPCR. The qPCR was able to detect the DNA of at least 10,000 times dilution corresponding to 0.056 ng of DNA. It is believed that with the additional qPCR validations reported in this study, it can be used for differential diagnosis in the health surveillance of PNEFA.

Cell-Mediated Immunological Biomarkers and Their Diagnostic Application in Livestock and Wildlife Infected With Mycobacterium bovis

Mycobacterium bovis has the largest host range of the Mycobacterium tuberculosis complex and infects domestic animal species, wildlife, and humans. The presence of global wildlife maintenance hosts complicates bovine tuberculosis (bTB) control efforts and further threatens livestock and wildlife-related industries. Thus, it is imperative that early and accurate detection of M. bovis in all affected animal species is achieved. Further, an improved understanding of the complex species-specific host immune responses to M. bovis could enable the development of diagnostic tests that not only identify infected animals but distinguish between infection and active disease. The primary bTB screening standard worldwide remains the tuberculin skin test (TST) that presents several test performance and logistical limitations. Hence additional tests are used, most commonly an interferon-gamma (IFN-γ) release assay (IGRA) that, similar to the TST, measures a cell-mediated immune (CMI) response to M. bovis. There are various cytokines and chemokines, in addition to IFN-γ, involved in the CMI component of host adaptive immunity. Due to the dominance of CMI-based responses to mycobacterial infection, cytokine and chemokine biomarkers have become a focus for diagnostic tests in livestock and wildlife. Therefore, this review describes the current understanding of host immune responses to M. bovis as it pertains to the development of diagnostic tools using CMI-based biomarkers in both gene expression and protein release assays, and their limitations. Although the study of CMI biomarkers has advanced fundamental understanding of the complex host-M. bovis interplay and bTB progression, resulting in development of several promising diagnostic assays, most of this research remains limited to cattle. Considering differences in host susceptibility, transmission and immune responses, and the wide variety of M. bovis-affected animal species, knowledge gaps continue to pose some of the biggest challenges to the improvement of M. bovis and bTB diagnosis.

Fatty acids in rumen and meat of lambs fed with different condensed and hydrolysable tannin extracts

Five groups of lambs (n = 9 each) were used to test the effect of plant extracts rich in hydrolysable (HT) or condensed tannin (CT) on animal performance, fatty acid composition of rumen content and meat. The control group (CO) received a concentrate-based diet without tannins supplementation. The other groups received the same diet as the control lambs plus 4% chestnut (CH) and tara (TA) extracts as a source of HT and mimosa (MI) and gambier (GA) extracts as a source of CT. Dietary CH negatively affected animal performance. The rumen content of the different groups showed comparable levels of 18:3 c9c12c15, 18:2 c9c12, 18:2 c9t11, 18:1 t11 and 18:0, whereas 18:1 t10 was greater in CO. Also, 18:1 t10 tended to be lower in the rumen of HT than CT-fed lambs. These data were partially confirmed in meat, where CO showed a greater percentage of individual trans 18:1 fatty acids in comparison with tannins-fed groups. Our findings challenge some accepted generalizations on the use of tannins in ruminant diets as they were ineffective to favour the accumulation of dietary PUFA or healthy fatty acids of biohydrogenation origin in the rumen content and lamb meat, but suggest a general action of tannins on the whole biohydrogenation process.

Inflammation of a Posterior Ciliary Artery in a Naive Cynomolgus Macaque

This brief communication describes a previously unreported background lesion in the eye of a naive cynomolgus macaque. Inflammation of a posterior ciliary artery was, in this case, morphologically similar to vascular inflammation of other tissues described in naive cynomolgus macaques. However, the available literature does not describe this lesion at this anatomical site. The affected animal did not present with any abnormal clinical signs and ophthalmological examinations were within normal limits. Toxicologic pathologists should be aware of this finding in order to help differentiate it from a test item–related finding.

Livestock rabies in Pará state, Brazil: a descriptive study (2004 to 2013)

ABSTRACT: Rabies is an important zoonosis to public health associated with lethal encephalitis and economic losses. Analysis of its spatial distribution is a meaningful tool in understanding its dispersion, which may contribute to the control and prophylaxis of the disease. This study analyzed the spatial-temporal distribution of rabies outbreaks in livestock in Pará state, Brazil, from 2004 to 2013. We used records of neurological syndromes obtained from the state’s livestock authority (Adepará). The analysis recorded 711 neurological syndromes reports in livestock, of which 32.8% were positive for rabies. In 8% of the neurological syndromes (n=57) was not possible to perform the analysis because of bad-packaging conditions of the samples sent. Outbreaks involved at least 1,179 animals and cattle were the most affected animal species (76.8%). The numbers of reported neurological syndromes and of rabies outbreak shad strong positive correlation and exhibited decreasing linear trend. Spatially, most outbreaks occurred in two mesoregions in Pará (Northeast and Southeast). One of the justifications for this spatial distribution may be related with the distribution of the animals in the state, since these mesoregions are the largest cattle producers in Pará and have most of their territory deforested for pasture implementation.

Α de novo 3.8-Mb inversion affecting the EDA and XIST genes in a heterozygous female calf with generalized hypohidrotic ectodermal dysplasia

Background In mammals, hypohidrotic ectodermal dysplasia (HED) is a genetic disorder that is characterized by sparse hair, tooth abnormalities, and defects in cutaneous glands. Only four genes, EDA, EDAR, EDARADD and WNT10A account for more than 90% of HED cases, and EDA, on chromosome X, is involved in 50% of the cases. In this study, we explored an isolated case of a female Holstein calf with symptoms similar to HED. Results Clinical examination confirmed the diagnosis. The affected female showed homogeneous hypotrichosis and oligodontia as previously observed in bovine EDAR homozygous and EDA hemizygous mutants. Under light microscopy, the hair follicles were thinner and located higher in the dermis of the frontal skin in the affected animal than in the control. Moreover, the affected animal showed a five-fold increase in the number of hair follicles and a four-fold decrease in the diameter of the pilary canals. Pedigree analysis revealed that the coefficient of inbreeding of the affected calf (4.58%) was not higher than the average population inbreeding coefficient (4.59%). This animal had ten ancestors in its paternal and maternal lineages. By estimating the number of affected cases that would be expected if any of these common ancestors carried a recessive mutation, we concluded that, if they existed, other cases of HED should have been reported in France, which is not the case. Therefore, we assumed that the causal mutation was dominant and de novo. By analyzing whole-genome sequencing data, we identified a large chromosomal inversion with breakpoints located in the first introns of the EDA and XIST genes. Genotyping by PCR-electrophoresis the case and its parents allowed us to demonstrate the de novo origin of this inversion. Finally, using various sources of information we present a body of evidence that supports the hypothesis that this mutation is responsible for a skewed inactivation of X, and that only the normal X can be inactivated. Conclusions In this article, we report a unique case of X-linked HED affected Holstein female calf with an assumed full inactivation of the normal X-chromosome, thus leading to a severe phenotype similar to that of hemizygous males.

High copy number of ovine gammaherpesvirus 2 DNA associated with malignant catarrhal fever–like syndrome in a lamb

Domestic and wild sheep are the natural reservoirs for ovine gammaherpesvirus 2 (OvHV-2), the causative agent of sheep-associated malignant catarrhal fever (SA-MCF). Virtually all adult sheep are infected with OvHV-2 under natural flock conditions, and infection is normally subclinical. MCF-like clinical signs and typical histologic lesions in sheep have been linked during case investigations at veterinary diagnostic laboratories; however, the confirmation of naturally occurring MCF in sheep is problematic. To date, the assays for detection of OvHV-2–specific antibodies or DNA are usually positive in sheep, regardless of health status, so mere detection of antibodies or the agent is of minimal diagnostic significance in this species. We document herein a naturally occurring MCF case in a 4-mo-old domestic lamb and demonstrate that the affected animal had 100–1,000 times more OvHV-2 copy numbers in tissues than in healthy adult and age-matched sheep. These results indicate that high copy numbers of viral DNA in tissues associated with characteristic lesions can be used to confirm the diagnosis of MCF in sheep.

Prospective study of ocular and periocular diseases in animals: 188 cases

ABSTRACT: Histopathology of the ocular and periocular tissues submitted for diagnosis and research is still incipient in Brazil, in contrast to veterinary clinical ophthalmology. In this study, ocular and periocular tissues from domestic and wild animal species, mainly from the state of Minas Gerais, Brazil, were evaluated between February 2012 and September 2015. The samples were analyzed grossly and microscopically. Histochemistry and immunohistochemistry were performed on some of the samples. The frequency, type of ocular alteration, affected animal species, and affected ocular or periocular tissues were recorded. One hundred eighty-eight ocular and periocular tissues from domestic and, occasionally, wild animals were examined. Nine animals presented two concurrent alterations, adding up to 197 alterations. Proliferative lesions were the most frequent (92), followed by traumatic (43), inflammatory (37), degenerative (18), developmental (4) and vascular/hemorrhagic diseases (3). The globe was the most affected structure (112), followed by eyelids (52), third eyelid (17), bulbar conjunctiva (14) and retrobulbar region (2). Neoplasms arising from periocular tissues were the most frequent alteration (60), possibly related to a more active surgical service and histopathologic evaluation request. Many animals presented ocular lesions that reflected systemic diseases, which were diagnosed by necropsy and examination of other organs. Particularly in cases of neoplasia, early detection and surgical treatment can prevent systemic involvement. Ocular histopathologic evaluation can provide better characterization and prognosis of the clinical-pathological condition of the patient as well.