Infection of the maternal-fetal interface and vertical transmission following low-dose inoculation of pregnant rhesus macaques (Macaca mulatta) with an African-lineage Zika virus.

BACKGROUND: Congenital Zika virus (ZIKV) infection can result in birth defects, including malformations in the fetal brain and visual system. There are two distinct genetic lineages of ZIKV: African and Asian. Asian-lineage ZIKVs have been associated with adverse pregnancy outcomes in humans; however, recent evidence from experimental models suggests that African-lineage viruses can also be vertically transmitted and cause fetal harm. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the pathway of vertical transmission of African-lineage ZIKV, we inoculated nine pregnant rhesus macaques (Macaca mulatta) subcutaneously with 44 plaque-forming units of a ZIKV strain from Senegal, (ZIKV-DAK). Dams were inoculated either at gestational day 30 or 45. Following maternal inoculation, pregnancies were surgically terminated seven or 14 days later and fetal and maternal-fetal interface tissues were collected and evaluated. Infection in the dams was evaluated via plasma viremia and neutralizing antibody titers pre- and post- ZIKV inoculation. All dams became productively infected and developed strong neutralizing antibody responses. ZIKV RNA was detected in maternal-fetal interface tissues (placenta, decidua, and fetal membranes) by RT-qPCR and in situ hybridization. In situ hybridization detected ZIKV predominantly in the decidua and revealed that the fetal membranes may play a role in ZIKV vertical transmission. Infectious ZIKV was detected in the amniotic fluid of three pregnancies and one fetus had ZIKV RNA detected in multiple tissues. No significant pathology was observed in any fetus; and ZIKV did not have a substantial effect on the placenta. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that a very low dose of African-lineage ZIKV can be vertically transmitted to the macaque fetus during pregnancy. The low inoculating dose used in this study suggests a low minimal infectious dose for rhesus macaques. Vertical transmission with a low dose in macaques further supports the high epidemic potential of African ZIKV strains.

Candidatus Neoehrlichia mikurensis and Hepatozoon sp. in voles (Microtus spp.): occurrence and evidence for vertical transmission.

Candidatus Neoehrlichia mikurensis (CNM) and Hepatozoon spp. are important vector-borne parasites of humans and animals. CNM is a relatively recently discovered pathogen of humans. Hepatozoon are parasites of reptiles, amphibians and mammals, commonly found in rodents and carnivores worldwide. The present study aimed to determine the prevalence of CNM and Hepatozoon spp. in three species of Microtus and to assess the occurrence of vertical transmission in naturally-infected voles. Molecular techniques were used to detect pathogen DNA in blood and tissue samples of captured voles and their offspring. The prevalence of CNM in the vole community ranged 24-47% depending on Microtus species. The DNA of CNM was detected in 21% of pups from three litters of six infected Microtus dams (two Microtus arvalis and one M. oeconomus) and in 3/45 embryos (6.6%) from two litters of eight CNM-infected pregnant females. We detected Hepatozoon infection in 14% of M. arvalis and 9% of M. oeconomus voles. Hepatozoon sp. DNA was detected in 48.7% of pups from seven litters (6 M. arvalis and 1 M. oeconomus) and in two embryos (14.3%) obtained from one M. arvalis litter. The high prevalence of CNM infections in the Microtus spp. community may be a result of a relatively high rate of vertical transmission among naturally infected voles. Vertical transmission was also demonstrated for Hepatozoon sp. in M. arvalis and M. oeconomus. Our study underlines the significance of alternative routes of transmission of important vector-borne pathogens.

Low transmission rates of Equine infectious anemia virus (EIAV) in foals born to seropositive feral mares inhabiting the Amazon delta region despite climatic conditions supporting high insect vector populations.

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.

A Novel Pathway for Porcine Epidemic Diarrhea Virus Transmission from Sows to Neonatal Piglets Mediated by Colostrum.

The mechanisms of colostrum-mediated virus transmission are difficult to elucidate because of the absence of experimental animal models and the difficulties in tissue sample collection from mothers in the peripartum period. Porcine epidemic diarrhea virus (PEDV) is a reemerging enteropathogenic coronavirus that has catastrophic impacts on the global pig industry. PEDV primarily infects neonatal piglets by multiple routes, especially 1- to 2-day-old neonatal piglets. Here, our epidemiological investigation and animal challenge experiments revealed that PEDV could be vertically transmitted from sows to neonatal piglets via colostrum, and CD3+ T cells in the colostrum play an important role in this process. The results showed that PEDV colonizing the intestinal epithelial cells (IECs) of orally immunized infected sows could be transferred to CD3+ T cells located just beneath the IECs. Next, PEDV-carrying CD3+ T cells, with the expression of integrin α4ß7 and CCR10, migrate from the intestine to the mammary gland through blood circulation. Arriving in the mammary gland, PEDV-carrying CD3+ T cells could be transported across mammary epithelial cells (MECs) into the lumen (colostrum), as illustrated by an autotransfusion assay and an MECs/T coculture system. The PEDV-carrying CD3+ T cells in colostrum could be interspersed between IECs of neonatal piglets, causing intestinal infection via cell-to-cell contact. Our study demonstrates for the first time that colostrum-derived CD3+ T cells comprise a potential route for the vertical transmission of PEDV. IMPORTANCE The colostrum represents an important infection route for many viruses. Here, we demonstrate the vertical transmission of porcine epidemic diarrhea virus (PEDV) from sows to neonatal piglets via colostrum. PEDV colonizing the intestinal epithelial cells could transfer the virus to CD3+ T cells located in the sow intestine. The PEDV-carrying CD3+ T cells in the sow intestine, with the expression of integrin α4ß7 and CCR10, arrive at the mammary gland through blood circulation and are transported across mammary epithelial cells into the lumen, finally leading to intestinal infection via cell-to-cell contact in neonatal piglets. Our study not only demonstrates an alternative route of PEDV infection but also provides an animal model of vertical transmission of human infectious disease.

Role of dense granule antigen 7 in vertical transmission of Neospora caninum in C57BL/6 mice infected during early pregnancy.

Neosporosis is a parasitic disease affecting the health of dogs and cattle worldwide. It is caused by Neospora caninum, an obligate intracellular apicomplexan parasite. Dogs are its definitive host, it mostly infects livestock animals, especially cattle that acts as intermediate host. It is necessary to have well-established models of abortion and vertical transmission in experimental animals, in order to determine basic control measures for the N. caninum infection. We evaluated the role of N. caninum dense granule antigen 7 (NcGRA7) in the vertical transmission of N. caninum using the C57BL/6 pregnant mouse model. We inoculated mice on day 3.5 of pregnancy with parental Nc-1 or NcGRA7-deficient parasites (NcGRA7KO). Post-mortem analyses were performed on day 30 after birth and the surviving pups were kept until day 30 postpartum. The number of parasites in the brain tissues of offspring from NcGRA7KO-infected dams was significantly lower than that of the Nc-1-infected dams under two infection doses (1 × 106 and 1 × 105 tachyzoites/mouse). The vertical transmission rates in the NcGRA7KO-infected group were significantly lower than those of the Nc1-infected group. To understand the mechanism by which the lack of NcGRA7 decreases the vertical transmission, pregnant mice were sacrificed on day 13.5 of pregnancy (10 days after infection), although parasite DNA was detected in the placentas, no significant difference was found between the two parasite lines. Histopathological analysis revealed a greater inflammatory response in the placentas from NcGRA7KO-infected dams than in those from the parental strain. This finding correlates with upregulated chemokine mRNA expression for CCL2, CCL8, and CXCL9 in the placentas from the NcGRA7KO-infected mice. In conclusion, these results suggest that loss of NcGRA7 triggers an inflammatory response in the placenta, resulting in decreased vertical transmission of N. caninum.

Effect of parity segregation on Mycoplasma hyopneumoniae infection dynamics and pneumonic lesions in pigs / Efeito da ordem de parto segregada sobre a dinâmica de infecção de Mycoplasma hyopneumoniae e lesões pulmonares ao abate

Gilts represent a group risk for Mycoplasma hyopneumoniae vertical transmission in swine herds. Therefore, parity segregation can be an alternative to control M. hyopneumoniae infections. The study evaluated the effect of parity segregation on M. hyopneumoniae infection dynamics and occurrence and severity of lung lesions at slaughter. For that, three multiple site herds were included in the study. Herd A consisted of the farm where gilts would have their first farrowing (parity order (PO) 1). After the first farrowing PO 1 sows were transferred to herd B (PO2-6). Herd C was a conventional herd with gilt replacement (PO1-6). Piglets born in each herd were raised in separated nursery and finishing units. Sows (n = 33 (A), 37 (B), 34 (C)) in all herds were sampled prior to farrowing and piglets (n = 54 (A), 71 (B), 66 (C)) were sampled longitudinally at 21, 63, 100, 140 days of age and at slaughter for M. hyopneumoniae detection by PCR and lung lesions scoring. M. hyopneumoniae prevalence in sows did not differ among herds. Prevalence of positive piglets was higher at weaning in the PO1 herd (A) (P < 0.05). However, prevalence of positive pigs from 100 days of age to slaughter age was higher in the PO2-6 herd (B) (P < 0.05). Lung lesion occurrence and severity were higher in herd B. The authors suggested that the lack of a proper gilt acclimation might have influenced the results, leading to sows being detected positive at farrowing, regardless of the parity.

As leitoas consistem em um grupo de risco na transmissão vertical de Mycoplasma hyopneumoniae dentro do sistema de produção de suínos. Dessa forma, a segregação de partos poderia ser utilizada como alternativa para controlar as infecções por M. hyopneumoniae. O objetivo deste estudo foi avaliar o efeito da segregação de partos sobre a dinâmica de infecção de M. hyopneumoniae e a ocorrência e severidade das lesões pulmonares ao abate. Para isso três sistemas de produção de suínos com três sítios cada foram incluídos no estudo. A granja A consistia da unidade onde as leitoas tem o primeiro parto, ou seja, alojava somente de fêmeas de ordem de parto 1 (Granja OP1). Após o primeiro parto as fêmeas OP1 foram transferidas para a granja B (Granja OP2-6), ou seja, consistia de fêmeas de ordem de parto 2 a 6, e a granja C consistiu em uma granja convencional com reposição de leitoas (Granja OP1-6), com fêmeas de ordem de parto 1 a 6. Os leitões nascidos de cada granja foram transferidos e criados em creches e terminações segregadas. As matrizes (n = 33 (A), 37 (B), 34 (C)) de todas as granjas do estudo foram amostradas previamente ao parto e os leitões (n = 54 (A), 71 (B), 66 (C)) foram amostrados longitudinalmente aos 21, 63, 100 e 140 dias de idade e ao abate. Em todos os momentos de coleta, as amostras foram avaliadas por PCR para detecção de M. hyopneumoniae. As lesões pulmonares foram avaliadas e escores de lesão foram atribuídos ao abate. A prevalência de matrizes positivas para M. hyopneumoniae não diferiu entre as granjas (P > 0,05). A prevalência ao desmame foi maior na granja A (OP1) (P < 0,05). No entanto, dos 100 dias de idade até o abate a prevalência de leitões positivos para M. hyopneumoniae foi maior na granja B (OP2-6) (P < 0,05). A ocorrência e severidade de lesões pulmonares foram maiores na granja B. Os autores sugerem que a falta de uma aclimatação adequada das leitoas pode ter influenciado nos resultados, levando à detecção de matrizes positivas ao parto, independente da ordem de parto.

No Evidence of the Vertical Transmission of Non-Virulent Infectious Salmon Anaemia Virus (ISAV-HPR0) in Farmed Atlantic Salmon.

The nonvirulent infectious salmon anaemia virus (ISAV-HPR0) is the putative progenitor for virulent-ISAV, and a potential risk factor for the development of infectious salmon anaemia (ISA). Understanding the transmission dynamics of ISAV-HPR0 is fundamental to proper management and mitigation strategies. Here, we demonstrate that ISAV-HPR0 causes prevalent and transient infections in all three production stages of Atlantic salmon in the Faroe Islands. Phylogenetic analysis of the haemagglutinin-esterase gene from 247 salmon showed a clear geographical structuring into two significantly distinct HPR0-subgroups, which were designated G2 and G4. Whereas G2 and G4 co-circulated in marine farms, Faroese broodfish were predominantly infected by G2, and smolt were predominantly infected by G4. This infection pattern was confirmed by our G2- and G4-specific RT-qPCR assays. Moreover, the HPR0 variants detected in Icelandic and Norwegian broodfish were never detected in the Faroe Islands, despite the extensive import of ova from both countries. Accordingly, the vertical transmission of HPR0 from broodfish to progeny is uncommon. Phylogenetic and statistical analysis suggest that HPR0 persists in the smolt farms as "house-strains", and that new HPR0 variants are occasionally introduced from the marine environment, probably by HPR0-contaminated sea-spray. Thus, high biosecurity-including water and air intake-is required to avoid the introduction of pathogens to the smolt farms.

Vertical transmission and kinetic of antibodies anti-Neospora caninum in naturally infected lambs in the semiarid region of Brazil.

Aimed with this study to evaluate vertical transmission of Neospora caninum in naturally infected sheep and to monitor the kinetics of antibodies against this protozoon in their lambs. Therefore, 48 pregnant ewes, from five herds, were divided into two groups: G1 - positive for anti-N. caninum antibodies, with 19 animals; and G2 - seronegative, with 29 animals. Blood samples were taken from the ewes and their lambs, immediately after birth, before ingesting colostrum, and 2, 7, 14, 21, 28, 35, 42, 49 and 56 days after birth. Analysis on serum antibodies was performed using the indirect immunofluorescent antibody test. Among the 19 seropositive mothers, six (31.6%) gave birth to lambs seropositive before ingesting colostrum and it was found that these lambs remained positive until the end of the study (56 days). Only one of the lambs, from a ewe that presented an antibody titer of 200, seroconverted after ingestion of colostrum. All the lambs that had been born from negative mothers remained negative throughout the experimental period. It was concluded that transplacental transmission was an important form of diffusion of N. caninum in the herds studied and that seropositive lambs maintained circulating antibodies during the period analyzed.

Establishment and validation of a guinea pig model for human congenital toxoplasmosis.

BACKGROUND: Toxoplasma gondii is an obligate intracellular parasite with a worldwide distribution. Congenital infection in humans and animals may lead to severe symptoms in the offspring, especially in the brain. A suitable animal model for human congenital toxoplasmosis is currently lacking. The aim of this study is to establish and validate the guinea pig as a model for human congenital toxoplasmosis by investigating the impact of the T. gondii infection dose, the duration of infection and the gestational stage at infection on the seroconversion, survival rate of dams, fate of the offspring, T. gondii DNA loads in various offspring tissues and organs and the integrity of the offspring brain. METHODS: Pregnant guinea pigs were infected with three different doses (10, 100, 500 oocysts) of T. gondii strain ME49 at three different time points during gestation (15, 30, 48 days post-conception). Serum of dams was tested for the presence of T. gondii antibodies using immunoblotting. T. gondii DNA levels in the dam and offspring were determined by qPCR. Offspring brains were examined histologically. RESULTS: We found the survival rate of dams and fate of the offspring to be highly dependent on the T. gondii infection dose with an inoculation of 500 oocysts ending lethally for all respective offspring. Moreover, both parameters differ depending on the gestational stage at infection with infection in the first and third trimester of gestation resulting in a high offspring mortality rate. The duration of infection was found to substantially impact the seroconversion rate of dams with the probability of seroconversion exceeding 50% after day 20 post-infection. Furthermore, the infection duration of dams influenced the T. gondii DNA loads in the offspring and the integrity of offspring brain. Highest DNA levels were found in the offspring brain of dams infected for ≥ 34 days. CONCLUSION: This study contributes to establishing the guinea pig as a suitable model for human congenital toxoplasmosis and thus lays the foundation for using the guinea pig as a suitable animal model to study scientific questions of high topicality and clinical significance, which address the pathogenesis, diagnosis, therapy and prognosis of congenital toxoplasmosis.

Pullorum Disease: Evolution of the Eradication Strategy.

The history of pullorum disease is closely intertwined with the history of avian health research and that of the poultry industry. The seriousness of the disease galvanized the attention and brought together, for the first time, the pioneers of poultry health research to work cooperatively on different aspects of the disease. Control of the disease made it possible for intensive poultry production to develop as the basis for the modern poultry industry. During the early 1900s, bacillary white diarrhea (BWD) was a devastating disease of young chickens threatening the developing poultry industry. Dr. Leo F. Rettger isolated and described the bacterial pathogen, Salmonella enterica serotype Pullorum, for the first time in 1900. BWD was renamed pullorum disease in 1929. In subsequent years, Rettger and coworkers were able to reproduce the disease and fulfill Koch's postulates. Rettger et al. also showed that Salmonella Pullorum was vertically transmitted, which was the first time that a pathogen was shown to be vertically transmitted. The development of serologic tests was of crucial importance because it led to the development of effective eradication methods to identify carrier birds and to exclude these birds from the breeder flocks. The negative impact of pullorum disease on the poultry industry ultimately was one of the major reasons that the National Poultry Improvement Plan (NPIP) was developed by scientists, the poultry industry, and the United States Department of Agriculture (USDA). Needless to say, the work of the pioneering researchers formed the basis for the control of the disease. The NPIP started in 1935, with 34 states participating in testing 4 million birds representing 58.2% of the birds hatched. The program rapidly expanded to 47 states by 1948 and tested more than 30 million birds. In 1967, all commercial chicken hatcheries participating in the NPIP were 100% free of pullorum and typhoid disease caused by Salmonella enterica serotype Gallinarum. This historical overview of pullorum disease describes in some detail the progress made, especially during the early years, toward controlling this disease using methodologies that were often very basic but nonetheless effective. One has to admire the ingenuity and persistence of the early researchers leading to their achievements considering the research tools that were available at the time.

Artículo histórico­Pulorosis: Evolución de las estrategias de erradicación La historia de la pulorosis está estrechamente relacionada con la historia de la investigación en salud aviar y de la industria avícola. La severidad de la enfermedad despertó la atención y reunió, por primera vez a los pioneros de la investigación en salud avícola para trabajar de manera cooperativa en diferentes aspectos de la enfermedad. El control de la enfermedad hizo posible que la producción avícola intensiva se desarrollara como base de la industria avícola moderna. A principios de la década de los 1900, la diarrea blanca bacilar (con las siglas en inglés BWD) era una enfermedad devastadora de pollos jóvenes que amenazaba la industria avícola en desarrollo. El Dr. Leo F. Rettger aisló y describió el patógeno bacteriano, Salmonella enterica serotipo Pullorum, por primera vez en 1900. La diarrea blanca bacilar pasó a llamarse pulorosis (pullorum disease) en 1929. En los años siguientes, Rettger y sus colaboradores pudieron reproducir la enfermedad y cumplir los postulados de Koch. Rettger y col. también mostraron que Salmonella Pullorum se transmitía verticalmente, y fue la primera vez que se demostró que un patógeno se transmitía verticalmente. El desarrollo de pruebas serológicas fue de crucial importancia porque condujo al desarrollo de métodos de erradicación efectivos para identificar aves portadoras y eliminar a estas aves de las parvadas reproductoras. El impacto negativo de la pulorosis en la industria avícola fue, en última instancia, una de las principales razones por las que los científicos, la industria avícola y el Departamento de Agricultura de los Estados Unidos (USDA) desarrollaron el Plan Nacional de Mejoramiento Avícola (NPIP). Es importante decir que el trabajo de los investigadores pioneros formó la base para el control de la enfermedad. El Plan Nacional de Mejoramiento Avícola comenzó en año 1935, con 34 estados participando en el análisis de 4 millones de aves que representaban el 58.2% de las aves producidas. El programa se expandió rápidamente a 47 estados en 1948 y evaluó a más de 30 millones de aves. En 1967, todas las plantas incubadoras de pollos comerciales que participaban en el Plan Nacional de Mejoramiento Avícola estaban 100% libres de pulorosis y tifoidea aviar causada por Salmonella enterica serotipo Gallinarum. Esta reseña histórica de la pulorosis describe con cierto detalle el progreso realizado, especialmente durante los primeros años, hacia el control de esta enfermedad utilizando metodologías que a menudo eran muy básicas no obstante efectivas. Es admirable el ingenio y la persistencia de los primeros investigadores que los llevaron a sus logros considerando las herramientas de investigación que estaban disponibles en ese momento.

Early onset of clinical leishmaniosis in a litter of pups with evidence of in utero transmission.

BACKGROUND: Canine leishmaniosis (CanL) is a zoonotic disease caused by Leishmania infantum. Although usually transmitted by phlebotomine sand flies, infection by vertical transmission and by blood transfusion have also been reported. METHODS: We describe the very early onset of clinical leishmaniosis, starting from 2 months of age, in a litter of pups born to an infected dam and sire. Seven pups from the litter of nine living in different households showed alopecic, exfoliative dermatitis and ulcerative cutaneous lesions. All pups and both parents were tested on at least one occasion both serologically, by enzyme-linked immunosorbent assay (ELISA), and by polymerase chain reaction (PCR) targeting the Leishmania ribosomal operon internal transcribed spacer 1 region and a short fragment of the kinetoplast minicircle; positive amplicons were sequenced. RESULTS: All nine pups were PCR positive for L. infantum verified by DNA sequencing, seven were positive by conjunctival, five by blood, four by lymph node, and one by skin PCR from an ulcerative lesion. Both pups with no clinical signs were seronegative, while five of the seven pups with dermatologic abnormalities were seropositive by ELISA. The sire had typical clinical dermatologic and visceral findings of CanL, was seropositive and PCR positive for L. infantum in the lymph node and fluid from the vas deferens tested after the testes were removed by castration. The dam was sub-clinically infected and seronegative, but positive by blood, lymph node and conjunctival PCR for L. infantum. Allopurinol administered to all clinically affected dogs resulted in clinical recovery. CONCLUSIONS: Infection with L. infantum in both parents, the very early age of clinical onset among most of the pups, and the fact that the puppies were born and detected with signs of leishmaniosis in the winter, which is a season without sand fly activity in Israel, strongly suggest vertical transmission. Awareness of the possibility of vertical transmission of L. infantum and infection in littermates should be increased. It is recommended that littermates of young dogs with clinical leishmaniosis should be tested for sub-clinical infection as they may also be infectious to sand flies and thus to other dogs and to humans. Restricting the mating of infected bitches should also be considered to prevent the vertical transmission of the infection.

A comparative efficacy test of 1 versus 2 doses of CIRCOQ PCV2 subunit vaccine against naturally occurring PCV2-type d in piglets with high maternally derived antibodies (MDAs) on a Vietnamese swine farm.

The aim of this study was to evaluate the protective efficacy of the CIRCOQ porcine circovirus type 2 (PCV2) subunit vaccine in piglets with high maternally derived antibodies (MDAs) against disease caused by natural infection with PCV2d. A total of 130 weaned, 21-day-old healthy pigs was allocated into 3 trial groups. The signs of respiratory disorder were higher in unvaccinated pigs than in vaccinated pigs at 13 to 17 weeks old (P < 0.05), 18 to 22 weeks old (P < 0.001), and 23 to 27 weeks old (P < 0.01). The unvaccinated pigs had an early rate of dermatitis at 8 to 12 weeks old (10.0%), 13 to 17 weeks old (30.0%), 18 to 22 weeks old (46.7%), and 23 to 27 weeks old (33.3%), while there were no cases of dermatitis in vaccinated pigs. There was a significant difference (P < 0.05) in the mortality of pigs in the unvaccinated group and the 2-dosed vaccinated group. PCV2 viremia was detected in the blood and peaked at 105 days old in both unvaccinated pigs (Ct-adj = 8.40) and pigs vaccinated with 1 dose (Ct-adj = 6.37), while no detectable PCV2 virus was found in the blood of pigs vaccinated with 2 doses. At 77 and 105 days old, the PCV2 viremia load (Ct-adj) of unvaccinated pigs and those vaccinated with 1 dose was significantly higher (P < 0.05) than that of the 2-dosed vaccinated pigs. The body weight (BW), average weight gain (AWG), and average daily gain (ADG) in both groups of vaccinated pigs were significantly higher (P < 0.05) than those of unvaccinated pigs. The study vaccine was significantly efficacious in protecting vaccinated pigs against clinical symptoms, blood viral load, and mortality, as well as improving productivity, compared with unvaccinated pigs.

Le but de la présente étude était d'évaluer l'efficacité protectrice du vaccin sous-unitaire CIRCOQ du circovirus porcin de type 2 (PCV2) chez les porcelets ayant une grande quantité d'anticorps d'origine maternelle (MDA) contre la maladie causée par une infection naturelle par le PCV2d. Un total de 130 porcs sains sevrés âgés de 21 jours a été réparti dans trois groupes d'essai. Les signes de troubles respiratoires étaient plus élevés chez les porcs non vaccinés que chez les porcs vaccinés âgés de 13 à 17 semaines (P < 0,05), de 18 à 22 semaines (P < 0,001) et de 23 à 27 semaines (P < 0,01). Les porcs non vaccinés avaient un taux précoce de dermatite entre 8 et 12 semaines (10,0 %), 13 à 17 semaines (30,0 %), 18 à 22 semaines (46,7 %) et 23 à 27 semaines (33,3 %), alors qu'il n'y a eu aucun cas de dermatite chez les porcs vaccinés. Il y avait une différence significative (P < 0,05) dans la mortalité des porcs dans le groupe non vacciné et le groupe vacciné à deux doses. La virémie du PCV2 a été détectée dans le sang et a atteint un pic à 105 jours chez les porcs non vaccinés (Ct-adj = 8,40) et les porcs vaccinés avec une dose (Ct-adj = 6,37), tandis qu'aucun virus PCV2 détectable n'a été détecté dans le sang des porcs vacciné avec deux doses. À 77 et 105 jours, la charge de virémie PCV2 (Ct-adj) des porcs non vaccinés et de ceux vaccinés avec une dose était significativement plus élevée (P < 0,05) que celle des porcs vaccinés à deux doses. Le poids corporel (BW), le gain de poids moyen (AWG) et le gain quotidien moyen (ADG) dans les deux groupes de porcs vaccinés étaient significativement plus élevés (P < 0,05) que ceux des porcs non vaccinés. Le vaccin de l'étude s'est avéré significativement efficace pour protéger les porcs vaccinés contre les symptômes cliniques, la charge virale sanguine et la mortalité, ainsi que pour améliorer la productivité, par rapport aux porcs non vaccinés.(Traduit par Docteur Serge Messier).

DETECTION OF DEER ATADENOVIRUS A DNA IN DAM AND OFFSPRING PAIRS OF ROCKY MOUNTAIN MULE DEER (ODOCOILEUS HEMIONUS HEMIONUS) AND ROCKY MOUNTAIN ELK (CERVUS CANADENSIS NELSONI).

Adenovirus hemorrhagic disease affects primarily mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), Rocky Mountain elk (Cervus canadensis nelsoni), and moose (Alces alces) in their first year of life. The method by which the causative virus, Deer atadenovirus A, is maintained in the environment and transmitted to neonates is unknown. In this study, we investigated the potential transmission of the virus from dam to offspring in Rocky Mountain mule deer (Odocoileus hemionus hemionus) and elk in western Wyoming, US. We sampled dams before parturition during placement of vaginal implant transmitters and at parturition and sampled neonates during capture in their first days of life. We also tested for the virus in mortalities submitted for pathologic examination and laboratory analysis. We detected viral DNA in samples from all time points tested but did not find a connection between positive dams and offspring mortalities associated with adenovirus hemorrhagic disease. Although we did not find direct evidence of transmission events between dams and offspring, asymptomatic animals shedding of Deer atadenovirus A, are a likely source of infection in neonates.

Field infection of a gilt and its litter demonstrates vertical transmission and effect on reproductive failure caused by porcine circovirus type 3 (PCV3).

BACKGROUND: PCV3 is a member of the Circovirus family, associated with disease and mortality in pigs. It is not clear whether PCV3 putatively causes clinical symptoms and disease. In the present case, we reported a gilt infected with PCV3 associated with reproductive failures, vertical transmission, tissue lesions, viral replication by in situ hybridization, and the hypothesis that some strains of PCV3 clade one are associated with reproductive failures at the field level. CASE PRESENTATION: In May 2019, a pig farm in Colombia reported increased reproductive failures, and the presence of PCV3 in gilts and sows was established in a single form or coinfections, mainly with PCV2 and PPV7. Ten sows with a single infection with PCV3 were found, and one gilt with a pre-farrowing serum viral load above 103 was studied. This gilt was followed up during the pre-farrowing, farrowing period and on her litter for 6 weeks. During dystocic farrowing, a mummy and ten piglets were released, including two weak-born piglets. The highest viral loads for PCV3 were found in the mummy and the placenta. In the weak-born piglets, there were viral loads both in serum and in tissues, mainly in the mesenteric ganglia and lung. Replication of PCV3 in these tissues was demonstrated by in situ hybridizations. PCV3 was also found in the precolostrum sera of piglets and colostrum, showing vertical transmission. The viral load in piglets decreased gradually until week six of life. The viral genome's complete sequencing was made from the mummy, and its analysis classified it as PCV3 clade one. CONCLUSIONS: This report confirms that PCV3 can cause disease at the field level, and putatively, in this case, we find the generation of reproductive failures. The ability of PCV3 to cause disease as a putative pathogen may be associated with the viral load present in the pig and the strain that is affecting the farm. For this case, we found that viral loads above 103 (4.93 log genomic copies / mL) in the gilt were associated with clinical manifestation and that some PCV3 strains belonging to clade one are more associated with the reproductive presentation.

Transplacental transmission of Neospora caninum to lambs in successive pregnancies of naturally infected sheep in Southern Brazil.

This study aims to report the detection of N. caninum DNA in a newborn lamb (1) with neurological signs and congenital neosporosis and in a stillborn lamb (2), both born from the same ewe in a herd of Southern Brazil. The lambs were born during different pregnancies of a Suffolk ewe seropositive to N. caninum and seronegative to T. gondii. Histopathological lesions were observed only in the central nervous system of the lambs. The newborn lamb (1) showed mild and focal gliosis in the frontal lobe. In the hippocampal region of the stillborn lamb (2), lymphoplasmacytic perivascular cuffs and N. caninum cysts were observed in the cytoplasm of neurons and confirmed by IHC. PCR was performed using brain samples to detect the protozoa N. caninum and Toxoplasma gondii. The infection with N. caninum was confirmed in the newborn lamb (1) by PCR and in the stillborn lamb (2) by histopathology, immunohistochemistry, and PCR tests.

Disseminated Toxoplasmosis in a Narrow-Ridged Finless Porpoise (Neophocaena asiaeorientalis) with Transplacental Embryonal Transmission.

We describe a case of systemic toxoplasmosis in a female adult narrow-ridged finless porpoise (Neophocaena asiaeorientalis) found in May 2018 inside a gillnet set in the Ariake Sound, southern Japan. The main lesions observed were lymphoplasmacytic and focally necrotizing encephalitis, necrotizing to granulomatous adrenalitis, myocarditis, and inflammation in the intestinal wall, associated with protozoal tissue cysts and tachyzoites. Additionally, the individual had a 5.6 mm (crown-rump length) early-stage embryo in the left uterine horn, which had multifocal necrotizing lesions with intralesional tissue cysts and tachyzoites in the parenchyma. Immunohistochemistry and PCR and sequencing of the internal transcribed spacer 1 region confirmed a Toxoplasma gondii infection. Further genotyping revealed an atypical type II genotype with a type I pattern for the Apico locus. Narrow-ridged finless porpoises are an endangered coastal species already facing various anthropogenic threats. Toxoplasmosis, especially with its ability to transmit to an early-stage embryo, should be considered an emerging threat to this vulnerable species.

Systemic coccidioidomycosis in a llama cria native to Missouri.

A 3-mo-old male llama was examined because of a 4-wk history of lethargy and ill thrift. Clinical examination revealed subcutaneous masses in the left prescapular and right inguinal regions, mild ataxia, a slight head tilt to the right, and right ear droop. The cria died before clinical workup was complete. At autopsy, there was generalized lymphadenomegaly, a hepatic nodule, a midbrain mass causing rostral compression of the cerebellum, and internal hydrocephalus. Microscopic findings included pyogranulomatous lymphadenitis, meningoencephalitis, hepatitis, and bronchopneumonia. Intralesional fungal spherules, most consistent with Coccidioides spp., were identified in the lymph nodes, lung, and brain. Fungal culture, single-nucleotide variation genotyping real-time PCR, and DNA sequencing confirmed Coccidioides posadasii. The dam of the cria was native to Arizona and had been moved to Missouri ~2.5 y previously. Agar gel immunodiffusion assay of the herd revealed that only the dam was positive for Coccidioides spp.; 6 herdmates were negative. Computed tomography of the dam revealed multiple nodules within the lungs and liver, which were presumed to be an active coccidioidomycosis infection. This case of systemic coccidioidomycosis in a llama native to Missouri was presumably acquired by vertical transmission from the dam.

Evidence of possible vertical transmission of duck hepatitis A virus type 1 in ducks.

Duck hepatitis A virus (DHAV) causes a highly contagious and acute disease in ducklings younger than 3 weeks of age and spreads rapidly by horizontal transmission to all susceptible ducklings in the flock. To date, there is no evidence of vertical transmission of DHAV-1. In a previous study, we identified a novel DHAV type 1 (DHAV-1) isolate that could infect adult ducks and induce laying drop. In this study, 30 non-embryonated duck eggs and 60 17-day-old embryos were collected from three breeding duck flocks with egg drop syndrome caused by DHAV-1 in China, and 30 17-day-old embryos were randomly selected from the 60 embryos and allowed to hatch. DHAV-1 RNA was detected by RT-PCR in 10 of 30 non-embryonated eggs, 9 of 30 17-day-old embryos, 5 of 7 dead embryos and 5 of 23 newly hatched ducklings. Overall, 29 of 90 (32.2%) eggs and embryos were positive for DHAV-1. Three DHAV-1 strains were isolated from the dead duck embryos of the three breeding duck flocks, respectively. Pathogenicity studies showed that the three DHAV-1 isolates had median embryo lethal doses but were highly pathogenic to healthy ducklings. Compared with the DHAV reference strains, there were two specific amino acid mutation sites (F169 and S220 ) in VP1 of the three isolates. To the best of our knowledge, this is the first report that DHAV-1 is isolated from duck embryos. The findings provide evidence of possible vertical transmission of DHAV-1 from breeding ducks to ducklings.

Vertical transmission of Toxoplasma gondii in naturally infected ewes in the semiarid region of Brazil.

To evaluate transplacental transmission of Toxoplasma gondii in naturally infected ewes, blood samples were collected from 55 pregnant ewes and their offspring, before ingestion of colostrum. From 16 offspring of positive ewes and nine offspring from negative ewes, blood samples were obtained after 48 h and 7, 14, 21, 28, 35, 42, 49 and 56 days after birth. T. gondii antibodies were detected in serum samples using the indirect fluorescence antibody test (IFAT ≥ 64). Four of the 30 positive ewes (13.3 %) had offspring positive for T. gondii before ingesting colostrum (vertical transmission). The colostrum antibody titers decreased every week, and only 20 % (2/10) of the lambs in continued to present detectable antibody titers until day 56 after birth. Therefore, vertical transmission of T. gondii in lambs was indication of occur and is an important route for transferring and maintaining the agent in sheep herds in the Brazilian semiarid region.

Pathological changes, distribution and detection of Brucella melitensis in foetuses of experimentally-infected does.

BACKGROUND: Brucellosis of goats is caused by Brucella melitensis. It is a re-emerging zoonotic disease in many countries due to transmission from domestic animals and wildlife such as ibex, deer and wild buffaloes. OBJECTIVE: To describe the pathological changes, identification and distribution of B. melitensis in foetuses of experimentally infected does. METHODS: Twelve female goats of approximately 90 days pregnant were divided into 4 groups. Group 1 was exposed intra-conjunctival to 100 µL of sterile PBS while goats of Groups 2, 3 and 4 were similarly exposed to 100 µL of an inoculum containing 109 CFU/mL of live B. melitensis. Goats of these groups were killed at 15, 30 and 60 days post-inoculation, respectively. Foetal fluid and tissues were collected for bacterial identification (using direct bacterial culture, PCR and immuno-peroxidase staining) and histopathological examination. RESULTS: Bilateral intra-conjunctival exposure of pregnant does resulted in in-utero infection of the foetuses. All full-term foetuses of group 4 were either aborted or stillborn, showing petechiations of the skin or absence of hair coat with subcutaneous oedema. The internal organs showed most severe lesions. Immune-peroxidase staining revealed antigen distribution in all organs that became most extensive in group 4. Brucella melitensis was successfully isolated from the stomach content, foetal fluid and various other organs. CONCLUSION: Vertical transmission of caprine brucellosis was evident causing mild to moderate lesions in different organs. The samples of choice for isolation and identification of B. melitensis are stomach content as well as liver and spleen tissue.