Akabane virus infection in the pregnant ewe. 2. Pathology of the foetus

A strain of Akabane virus (CSIRO 16) isolated from Culicoides brevitarsis was given three different passage treatments in the laboratory and then inoculated into ewes that were 32 to 36 days pregnant. The foetuses from these ewes were examined between the 69th and 106th days of gestation. The 39 infected ewes produced 55 foetuses of which 44 (80%) had severe developmental defects. Arthrogryposis and agenesis of the brain or hydranencephaly, were present in 43 of the foetuses. Other gross defects affecting variable proportions of foetuses were porencephaly, brachygnathism, scoliosis, hypoplasia of the lungs and agenesis or hypoplasia of the spinal cord. Histopathological findings covered a wide spectrum of defects that have previously been considered to occur over an extended range of foetal ages. These defects included skeletal muscle atrophy and degeneration, and in the brain, particularly in the cerebrum, cystic areas and malacia, general oedema, subependymal gliosis, perivascular cuffing and mineralised plaques. Similar lesions were seen in the pons and cerebellum. Extensive lesions, with and without inflammation were seen in the spinal cord.     

The pathology of Brucella ovis infection in the pregnant ewe

Extract

Bovine enzootic haematuria is essentially a neoplastic condition of the urinary bladder which is characterized by the clinical condition of haematuria. The appearance of haematuria which may be persistent or intermittent is followed by anaemia, wasting and usually death. The disease occurs in older animals of both sexes.     

Elisa test for the serodiagnosis of Akabane virus infection in cattle

Summary A simple ELISA test has been developed for the detection of IgG and IgM antibodies to Akabane virus in bovine serum. The test is specific and its sensitivity higher than the serum neutralisation assay. Detection of IgM antibodies can serve as a rapid method of diagnosing primary infection with Akabane virus. The superiority of ELISA resides mainly in the rapidity of performance and that it can be performed with inactivated reagents at high dilutions of serum samples. Thus it might enable the surveillance of spread of infection in zones prone to be affected by insect-borne viral diseases.

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La Prueba Elisa Para El Serodiagnostico De La Infeccion En Bovinos Con El Virus De Akabane

Resumen Se desarrolló una prueba ELISA simple, para la detección en sueor bovino de anticuerpos IgG e IgM del virus de Okabane. La prueba es específica y la sensibilidad superior a aquella de la seroneutralización. La detección de anticuerpos IgM puede servir como un método diagnóstico rápido para detectar infecciones primarias causadas por el virus. La superioridad de la prueba ELISA reside principalmente, en la rapidez de ejecución de la misma y que ésta puede realizarse con reactivos inactivados, a altas diluciones de la muestra de suero. Esta prueba ELISA podría facilitar la vigilancia epidemioloógica de la extensión de la enfermedad, en zonas en donde las condiciones ecológicas facilitarían el establecimiento de infecciones transmitidas por insectos.

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Un Test Elisa Pour Le Serodiagnostic De L'Infection A Virus Akabane Chez Le Betail

Résumé Un test ELISA simple a été développé pour la détection dans le sérum bovin des anticorps IgG et IgM dirigés contre le virus Akabane. Le test est spécifique et sa sensibilité est supérieure à celle du test de séro-neutralisation. La détection des anticorps IgM peut servir de méthode rapide pour diagnostiquer une infection primaire par le virus Akabane. La supériorité de l'ELISA réside essentiellement dans la rapidité de son exécution et en ce qu'il peut être réalisé avec des réactifs inactivés, et a de hautes dilutions des échantillons de sérums. De la sorte, il permet la surveillance de la propagation de l'infection dans les zones aptes à être affectées par les maladies transmises par arthropodes.

     

Effects of a porcine reproductive and respiratory syndrome virus infection on the development of the immune response against pseudorabies virus

The aim of this study was to investigate the effects of a porcine reproductive and respiratory syndrome virus (PRRSV) infection on the development of the immune response after pseudorabies virus (PRV) vaccination in pigs. Pigs were intranasally inoculated with the European PRRSV strain, Lelystad virus ter Huurne, and were vaccinated intramuscularly with PRV 2 weeks later (LV-PRV group). Control pigs were vaccinated with PRV only (PRV group). Eight weeks after PRV vaccination, pigs from both groups were challenged intranasally with wild-type PRV. We measured the lymphoproliferative, and the cytolytic responses to PRV of peripheral blood mononuclear cells (PBMC), isolated from blood samples. In addition, serum samples were examined for antibodies against PRV and LV. One week after PRV vaccination, PBMC proliferated abundantly to PRV in both groups. However, in the LV-PRV group the lymphoproliferative response declined after 1 week, whereas, in the PRV group, the lymphoproliferative response was high for 3 weeks and declined thereafter (P<0.05). After challenge, the lymphoproliferative response was 1 week earlier and was consistently and significantly higher in the PRV group than in the LV-PRV group. The PRV-specific killing was higher at 3 weeks after PRV vaccination and 5 weeks after PRV challenge 19+/-3 and 24+/-6%, respectively, in the PRV group, compared to 7+/-4 and 6+/-9%, respectively, in the LV-PRV group (P<0.05). However, later after vaccination and challenge the cytolytic response was identical in both groups. The antibody titre against PRV developed equally in both groups. After challenge, no PRV virus was isolated from both groups. From these results we conclude that, although PRRSV infection did cause changes in the time course of the T-lymphocyte response after PRV vaccination, PRRSV infection did not inhibit the development of vaccine-induced protection after PRV.     

Studies on reproduction in the goat. VII. Pregnancy and the development of the foetus and the foetal accessories of the goat

1. A total of 18 goats were ovariohysterectomized at different stages — 26 days to 145 days — of pregnancy.
2. The amniotic fluid increases from about 3.5 ml at 30 days to 600–1,000 ml per foetus at birth.
3. At birth the amount of allantoic fluid is approximately 600–1,100 ml and is to a small extent dependent on the number of foetuses.
4. The length of the foetus is about 1.4 cm at 30 days and 43 cm at 145 days, the lengthwise growth curve from the 30th day and onward being almost linear.
5. Hair follicles are visible around the 60th day and the eyes open between the 130th and 140th day.
6. The average length and weight of the goat kids at birth are 42.06 cm and 2.81 kg respectively.
7. The birth weight and length tend to increase with the increasing age of the dam.
8. The male does not appear to have any influence on the birth weight and length of the offspring.

     

Humoral immune response of calves to bluetongue virus infection

Humoral immune responses of 7 calves to bluetongue virus (BTV) infection were evaluated by plaque-reduction assay and immunoblotting. Most readily interpretable results were obtained with the immunoblot assay when colostrum-deprived calves were used, and sera were reacted with proteins in partially purified extracts of BTV. Viremia persisted in calves for 35 to 56 days, and BTV coexisted in blood for several weeks with virus-specific neutralizing antibody. Calves developed antibody to virus protein 2, the major determinant of virus neutralization, at 14 to 28 days after inoculation; this time interval also coincided with the appearance of neutralizing antibody in serum. Virus clearance in BTV-infected calves did not coincide with humoral immune responses to protein 2 or other virion proteins.     

Exercise alters the immune response to equine influenza virus and increases susceptibility to infection.

Equine influenza virus remains a major health concern for the equine industry in spite of ongoing vaccination programmes. Previous work has shown that the immune system of horses can be affected by strenuous exercise. The possible adverse consequence of exercise-induced alterations in lymphocyte responses measured in vitro was unknown. Here we demonstrate that subjecting vaccinated ponies to a 5 day strenuous exercise programme results in a significant suppression of their T cell-mediated immune response to equine influenza virus as measured by decreased lymphoproliferation and gamma interferon production measured in vitro. These same ponies also demonstrated increased susceptibility to influenza disease following a challenge exposure to the same strain of virus. Rested ponies that had received the same vaccine and challenge were completely protected from disease. Our results demonstrate that exercise-induced suppression of the equine immune response to influenza virus can be associated with an increased susceptibility to disease.     

A serological survey of Akabane virus infection in cattle and sheep in northwest China

Purpose

Akabane disease characterized mainly by fetal damage is a ruminant disease caused by insect-transmitted Akabane virus infection.

Methods

We investigated Akabane disease using serum neutralization tests in 446 blood samples collected from 187 cattle and 259 sheep of Xinjiang province, northwest China.

Results

(1) The overall prevalence rate of neutralizing antibody was 19.06?% (85/446), (2) the prevalence rates of Akabane disease in cattle and sheep were 20.32?% (38/187) and 18.15?% (47/259), respectively, (3) the disease prevalence rates were not significantly different between cattle and sheep, but significantly different among samples collected from different sampling months, (4) the disease was most prevalent in July when mosquitoes and culicoides were most active, and (5) the disease prevalence rates were significantly different between individuals with abortion experience and without abortion experience (P?<?0.05), suggesting that Akabane virus infection may significantly increase abortion risk in cattle and sheep.

Conclusions

To our knowledge, this is the first report confirming that Akabane virus infection is common in cattle and sheep of Xinjiang province, northwest China and providing useful epidemiological information for cattle and sheep abortion prevention and control.     

Evaluating the protective efficacy of a trivalent vaccine containing Akabane virus,Aino virus and Chuzan virus against Schmallenberg virus infection

Schmallenberg virus (SBV), an arthropod borne pathogen, spread rapidly throughout the majority of Europe since 2011. It can cause a febrile disease, milk drop, diarrhea, and fetal malformation in ruminants. SBV, a member of the Simbu serogroup within the genus Orthobunyavirus, is closely related to Akabane virus (AKAV) and Aino virus (AINOV) among others. In the present study, 4 Holstein-Friesian calves were immunized twice four weeks apart with a multivalent, inactivated vaccine against AKAV and AINOV. Another 4 calves were kept as unvaccinated controls. All animals were clinically, serologically and virologically examined before and after challenge infection with SBV. AKAV- and AINOV-specific neutralizing antibodies were detected one week before challenge infection, while SBV-specific antibodies were detectable only thereafter. SBV genome was detected in all vaccinated animals and 3 out of 4 controls in serum samples taken after challenge infection. In conclusion, the investigated vaccine was not able to prevent an SBV-infection. Thus, vaccines for other related Simbu serogroup viruses can not substitute SBV-specific vaccines as an instrument for disease control.     

Hepatic immune response in calves during acute subclinical infection with bovine viral diarrhoea virus type 1

Eight colostrum-deprived calves aged 8-12 weeks were inoculated intranasally with a non-cytopathic strain of bovine viral diarrhoea virus (BVDV) genotype-1 and the effects on the hepatic immune response were studied. Two calves were sacrificed at each of 3, 6, 9 and 14 days post-inoculation (dpi) and two uninoculated animals were used as negative controls. BVDV was detected in hepatic macrophages and monocytes from 3 to 14dpi and in Küpffer cells (KCs) from 6 to 14dpi. Increases in the numbers of MAC387(+) KCs and monocytes, but not interstitial macrophages, differentiated by morphological features, were evident in the liver following inoculation with BVDV. There was a substantial increase in the number of monocytes positive for tumour necrosis factor (TNF)-α, but only small increases in the numbers of TNF-α(+) KCs and interstitial macrophages and interleukin (IL)-6(+) monocytes, KCs and interstitial macrophages. There was an increase in the number of interstitial CD3(+) T lymphocytes in the liver, but no substantial changes in the numbers of circulating CD3(+) T lymphocytes, interstitial or circulating CD4(+) or CD8(+) T lymphocytes, or CD79αcy(+) B lymphocytes. Serum haptoglobin and serum amyloid A increased transiently at 12dpi. Upregulation of some pro-inflammatory cytokines by hepatic macrophages is evident in subclinical acute BVDV type 1 infection in calves.     

新城疫病毒感染绵羊诱导免疫应答反应的实验研究

为探索新城疫病毒(NDV)作为羊病毒病疫苗载体的可行性,验证NDV感染绵羊的可能性,本研究采用NDV Clone-30株分别通过滴鼻和气管灌注两种途径接种绵羊,接种后观察临床症状,检测接种动物排毒情况,通过血凝抑制试验检测接种绵羊特异性血凝抑制抗体,ELISA试验检测接种绵羊血清特异性IgG抗体,微量中和试验检测接种绵羊血清中和抗体.研究结果表明,NDV在绵羊体内是非致病性的,并且通过两种接种途径在绵羊体内均可以产生血凝抑制抗体、NDV特异性IgG抗体和中和抗体反应.本研究结果表明NDV有可能作为宿主限制性疫苗载体用于预防无特效疫苗的羊类疾病,且与气管灌注接种途径比,滴鼻接种途径相对安全.     

Intestinal mucosal immune response against virulent duck enteritis virus infection in ducklings

Duck virus enteritis (DVE) is an acute and contagious herpes virus infection of duck, geese and swans with high morbidity and mortality. The development of specific mucosal immune system against duck enteritis virus (DEV) infection for ducks has been hindered by a lack of knowledge concerning the purification of immunoglobulin A (IgA) of duck. In the present work, the method for purification of duck immunoglobulin A was developed, and the induction of intestinal mucosal immune responses against DEV was studied by orally infected ducklings with virulent DEV. The results showed that a continuous increased DEV DNA levels were observed in blood and various organs examined of orally infected ducklings throughout the infection, which was accompanied by the development of infection in ducklings from mild progressed to severe pathological lesions. Furthermore, a marked increased level of DEV-specific IgA and IgG antibodies in bile, serum and the intestinal tract, as well as the density of IgA⁺ cells in intestine were detected between 1 and 12 days p.i., followed by a drastic reduction of the antibody levels and the density of IgA⁺ cells at 15 days p.i. The results indicate that the DVE infection can stimulate both IgA-dominated antibody immune responses in the intestinal tract, and IgG-dominated antibody systemic immunity in the serum of ducklings orally inoculated with virulent DEV. The severe lesions of the villus epithelial cells and the lymphoid organs can suppress the intestinal mucosal immune responses.     

广西牛羊赤羽病和蓝舌病流行病学调查

为了解赤羽病病毒(AKAV)和蓝舌病病毒(BTV)2种虫媒病毒(Arbovirus)在广西的流行与分布情况,本研究对采集自2010年～2011年广西11市的706份牛、羊血清样品进行检测,共检测出AKAV抗体阳性样品382份,总阳性率为54.11％.其中山羊血清82份,阳性率为28.37％(82/289);牛血清300份,阳性率为71.94％(300/417).BTV抗体阳性样品279份,总阳性率为39.52％.其中山羊血清95份,阳性率为32.87％(95/289),牛血清样品184份,阳性率44.12％(184/417).同时检测出2种虫媒病毒抗体185份,占样品总数的26.20％.本研究结果表明2种虫媒病毒在广西广泛流行,并首次证明广西存在AKAV的感染.     

Cell mediated immune response of chicks following fowl adenovirus type-1 infection.

Cellular immune response of 6-week-old chickens infected with fowl adenovirus type-1 was evaluated by both in vivo and in vitro assay. In vitro assay, enumerating peripheral T lymphocyte by alphanaphthyl acetate esterase staining, revealed that cellular immunity appeared as early as 1 week post-infection and was maintained up to 5 weeks post-infection. In vivo assay by phytohaemagglutin skin test showed cellular immunity until 2 weeks post-infection. Thereafter no immunity was observed by this assay.     

Experimental placental transfer of Akabane virus in the hamster

Transplacental infection of hamster fetuses was produced by inoculation of pregnant hamsters with 10(6.3) plaque-forming units (PFU) of Akabane virus by either the intraperitoneal or the subcutaneous route. Virus with titers as high as 10(7.5) PFU/g of tissue was detected first in the placenta and later in the fetus. Virus could also be readily isolated from blood, lung, spleen, and liver of both pregnant and nonpregnant hamsters, but it reached higher titers and persisted longer in the placenta and fetus. Young dying at birth had Akabane virus titers as high as 10(7.3) PFU/g of brain tissue. Litter size was reduced by inoculation of the pregnant hamster at gestational day 11 or earlier, and survival of the newborn to 1 week of age was decreased by inoculation at gestational day 9 or later.     

The immune response and maternal antibody interference to a heterologous H1N1 swine influenza virus infection following vaccination

This study investigated the efficacy of a bivalent swine influenza virus (SIV) vaccine in piglets challenged with a heterologous H1N1 SIV isolate. The ability of maternally derived antibodies (MDA) to provide protection against a heterologous challenge and the impact MDA have on vaccine efficacy were also evaluated. Forty-eight MDA(+) pigs and 48 MDA(-) pigs were assigned to 8 different groups. Vaccinated pigs received two doses of a bivalent SIV vaccine at 3 and 5 weeks of age. The infected pigs were challenged at 7 weeks of age with an H1N1 SIV strain heterologous to the H1N1 vaccine strain. Clinical signs, rectal temperature, macroscopic and microscopic lesions, virus excretion, serum and local antibody responses, and influenza-specific T-cell responses were measured. The bivalent SIV vaccine induced a high serum hemagglutination-inhibition (HI) antibody titer against the vaccine virus, but antibodies cross-reacted at a lower level to the challenge virus. This study determined that low serum HI antibodies to a challenge virus induced by vaccination with a heterologous virus provided protection demonstrated by clinical protection and reduced pneumonia and viral excretion. The vaccine was able to prime the local SIV-specific antibody response in the lower respiratory tract as well as inducing a systemic SIV-specific memory T-cell response. MDA alone were capable of suppressing fever subsequent to infection, but other parameters showed reduced protection against infection compared to vaccination. The presence of MDA at vaccination negatively impacted vaccine efficacy as fever and clinical signs were prolonged, and unexpectedly, SIV-induced pneumonia was increased compared to pigs vaccinated in the absence of MDA. MDA also suppressed the serum antibody response and the induction of SIV-specific memory T-cells following vaccination. The results of this study question the effectiveness of the current practice of generating increased MDA levels through sow vaccination in protecting piglets against disease.     

Maternal and fetal effects of propofol anaesthesia in the pregnant ewe

The objective of this study was to determine the effects of propofol (PRF) on maternal and fetal cardiopulmonary function during the last trimester of pregnancy. Six pregnant 2-3 year-old Ripollesa sheep, each weighing 78+/-8 kg were used in the study and prepared by placing catheters in the maternal jugular vein and carotid artery. A catheter was also placed in the fetal femoral artery. Twenty-four hours later the sheep were anaesthetized with PRF (6 mg/kg intravenous (IV) followed by a continuous infusion at a rate of 0.4 mg/kg/min for 60 min) and cardiopulmonary data collected. Further data were collected for 105 min following termination of the infusion. The maternal mean arterial pressure (MAP) and diastolic arterial pressure (DAP) were significantly decreased (P<0.05) during the first 15 min of the infusion period, while the maternal pH was also significantly decreased. Maternal PaCO(2) and PaO(2) were significantly increased throughout the total infusion period. It was further observed that the fetal pH decreased significantly, throughout the infusion period, whereas the fetal MAP, DAP and PaCO(2) were significantly increased during the first 15 min of the infusion, after which time all parameters returned to control values. No differences in either maternal or fetal parameters were observed between control and recovery times.