猪瘟与大肠杆菌混合感染的防治

现在,猪病混合感染或继发感染问题十分严重。猪瘟是一种热性、高度接触性传染病,往往继发或混合感染一种或几种细菌性、病毒性疾病,其中在临床上猪瘟与大肠杆菌混合感染最为常见。1临床症状     

山羊痘病例的病理学诊断与防控

山羊痘是由山羊痘病毒引起的一种急性、热性、接触性传染病。其特征是发热,在无毛或少毛部位皮肤、黏膜及内脏器官发生痘疹,是所有动物痘病中最为严重的一种,被世界动物卫生组织(OIE)列为A类传染病,我国将其列为一类动物疾病。此外,该病在公共卫生方面也受到密切关注,中国、瑞典、印度依据流行病学和临床症状都有人类感染羊痘病毒的报道。据不同毒株的毒力差异,易感羊群的致     

痒病的防治措施与朊病毒

朊病毒是一种只有蛋白质而没有核酸的病毒,可以引起人类和动物中枢神经系统退行性病变。朊病毒病与艾滋病并列成为21世纪危害人类健康的顽疾。作者分别从病毒特性、感染途径和致病机理等方面,阐述了朊病毒的研究进展,并着重介绍了由朊病毒引起的代表性疾病绵羊痒病的流行病学特点、临床特征、病理变化、临床诊断要点及其综合防治措施,供广大兽医工作者和养殖户参考。     

博尔纳病

本文对博尔纳病的历史、病原学、流行病学、临床症状、病理学变化、诊断和防治措施等方面进行了简明的阐述。     

猪水疱病的防治

猪水疱病是由猪水疱病毒引起的一种急性传染病。发病率高,呈扩大流行性,主要以口部、蹄部、鼻端、腹部以及乳头周围皮肤发生水疱为主要特征性症状。在1966年,本病首次于意大利发现,1971年在香港发现,以后在世界各地相继发现。本病症状与口蹄疫极相似,但仅感染猪,不感染其它偶蹄兽,人类有一定的易感性。1病原特征猪水疱病病毒属于微核糖核酸病毒种肠道病     

痒病的防治措施与朊病毒

朊病毒是一种只有蛋白质而没有核酸的病毒,可以引起人类扣动物中枢神经系统退行性病变。朊病毒病与艾滋病并列成为21世纪危害人类健康的顽疾。作者分别从病毒特性、感染途径和致病机理等方面,阐述了朊病毒的研究进展,并着重介绍了由朊病毒引起的代表性疾病绵羊痒病的流行病学特点、临床特征、病理变化、临床诊断要点及其综合防治措施,供广大兽医工作者和养殖户参考。     

猪圆环病毒病的诊断与防治

猪圆环病毒(Porcine circovirus,PCV)病是一种主要感染仔猪或青年猪的传染病,较易发病,治愈难度大,死亡率高,给广大养殖户带来严重的经济损失,长期以来一直困扰着养殖业的持续健康发展。该文从猪圆环病毒病的病原、流行病学、临床症状、病理变化和危害、初步诊断及防治措施等方面进行了简要阐述。     

羊传染性口疮病的治疗与体会

羊口疮病是一种接触性的传染病,是由于羊只感染羊口疮病毒所引起的,该病传染性强,既能在牲畜之间传染,还可以传染给人类,造成人患病。羊口疮病在春初、冬末和秋季多发,主要传染源是病羊和带毒动物,传染范围较广,危害性大,但是主要发生在羔羊,对成年羊的危害性不高。笔者通过对羊口疮病的临床症状进行分析,提出了系统的治疗方案。     

禽流感的实验室诊断技术

禽流感是一种急性传染病,每次爆发不但给养禽业造成巨大经济损失,而且严重威胁人类的健康。由A型流感病毒引起的禽流感,其临床症状因感染禽的种类、年龄、病发感染情况及新感染毒株的毒力不同而表现不一致,其病理变化因感染病毒株毒力的高低、病程长短及     

疯牛病的传染途径及防控措施

疯牛病学名牛海绵状脑病,是一种由朊病毒引起的致死性人畜共患神经退行性疾病。病牛脑组织呈海绵状病变,传染给人类后可导致人类疯牛病——"克-雅病"。目前该病发病地区日益扩大,病例数上升,危害极大。从病原、临床症状、传染途径及防控措施4个方面对疯牛病以及人类感染朊病毒后所得"克-雅病"进行了总结。     

边界病研究进展

边界病(border disease,BD)是由边界病毒(BDV)引起绵羊和山羊的一种病毒性疾病,临床症状表现为母羊不孕、流产和死胎,以及羔羊体型异常,多毛,震颤,因此又称"多毛震颤病","茸毛症".该病的主要传播途径是垂直传播,持续性感染的羔羊是该疾病在绵羊中传播的潜在主要传染源.山羊相对绵羊感染症状相对较轻,主要表...     

边界病的研究进展

边界病（border disease,BD）是由边界病病毒（border disease virus,BDV）引起绵羊和山羊感染的一种传染性疾病,在世界范围内给畜牧业生产造成巨大的经济损失。该病临床表现为母羊生殖障碍,羔羊畸形、震颤、多毛等。BDV在绵羊、牛和猪的种间传播经常发生,给该病的诊断带来困难。目前,尚无有效的疫苗用于边界病的防控,因此,了解不同区域的边界病流行情况有助于防止其传播并优化控制措施。结合国内外近期研究报道,从病原学、流行病学、诊断措施等方面对边界病进行综述,以期为该病的防控工作提供参考。     

Borna disease: current knowledge and virus detection in France

For over two centuries, Borna disease (BD) has been described as a sporadically occurring infectious meningoencephalomyelitis affecting horses and sheep in Central Europe. Over the last decade, the BD epidemiology has been discussed. Firstly, its geographical distribution seems larger than what was previously thought. Secondly, the disease can affect a large number of warm-blooded animal species, including humans. The aetiological agent is the Boma disease virus (BDV), an enveloped, nonsegmented negative-stranded RNA virus classified in the new virus family Bornaviridae (Mononegavirales order). It can induce severe clinical signs of encephalitis with striking behavioural disturbances and may cause death. BDV genome has recently been detected in France in the blood and brain of several animal species (horses, bovines, foxes).     

Isolation of border disease virus from twin lambs in Alberta

We describe herein a field case of border disease (BD) in twin lambs. Both lambs were unthrifty, stunted, and one exhibited nervous signs characteristic of BD, with tremors of the head, neck, hind legs, and pelvis. Hairiness of the coat and excessive pigmentation, often seen in lambs with BD, were not observed. A noncytopathic virus, which showed cross-reactivity with bovine viral diarrhea (BVD) virus antiserum and BVD virus monoclonal antibodies, was isolated repeatedly from leukocytes from one lamb and from tissues of the other. Although the source of the virus is unknown, our results suggest that the dam of the affected twins had been infected during pregnancy. We used the BD virus isolated to inoculate pregnant ewes and experimentally reproduce the disease in a newborn lamb. Our findings indicate that leukocytes, rather than serum, should be utilized for BD virus isolation. Further, it is recommended that BD virus, rather than BVD virus, be used in serum neutralization tests when screening sheep for antibody titers.     

Border disease of sheep: the disease in the newborn, adolescent and adult.

Border disease (BD) is a condition of newborn sheep that results from congenital infection by a non-cytopathic pestivirus occurring during the first half of gestation. The expression of the virus is largely determined by the age of the fetus at the time of infection, producing four distinct disease syndromes: (1) early embryonic death, (2) abortion and stillbirth, (3) birth of lambs with malformations, and (4) birth of small, weak lambs, lacking characteristic clinical signs, but bearing features of immunosuppression. The effects of the virus infection during the developmental stages of the fetus are most apparent as distinctive clinical signs at the time of birth but a state of specific immuno-tolerance with associated virus persistence remains for the lifetime of the sheep. Although the clinical signs disappear with time, some effects of virus persistence may continue into adolescence and often into adulthood. Characteristic lesions are found in the nervous, endocrine, skeletal and integumentary, and immune systems.     

Borna disease virus: a mystery as an emerging zoonotic pathogen

For Central European veterinarians, Borna disease (BD) has been known for a long time as a sporadically occurring, progressive viral polioencephalomyelitis predominantly affecting horses and sheep and-as discovered in the last decade-an increasing number of domestic and zoo animals. The aetiological agent, the Borna disease virus (BDV), a negative-sense, single-stranded RNA virus classified in the new virus family Bornaviridae within the order Mononegavirales, can induce severe clinical signs typically of a viral encephalitis with striking behavioural disturbances. After an incubation period lasting a few weeks to several months, BDV-infection causes locomotor and sensory dysfunctions followed by paralysis and death. Natural infections seem to be subclinical in most cases. BD received world-wide attention when it was reported that sera and/or cerebrospinal fluids from neuro-psychiatric patients can contain BDV-specific antibodies. Since infected animals produce BDV-specific antibodies only after virus replication, it was assumed that the broad spectrum of BDV-susceptible species also includes man. However, reports describing the presence of other BDV-markers, i.e. BDV-RNA or BDV-antigen, in peripheral blood leukocytes or brain tissue of neuro-psychiatric patients are highly controversial and, therefore, the role of BDV in human neuro-psychiatric disorders is questionable. (c) 2001 Harcourt Publishers Ltd.     

The effect of infectious bursal disease virus on the immune system of turkeys

In 1979 it was reported that an infectious bursal disease virus (IBDV) isolated from a case of respiratory disease of turkeys differed antigenically from the chicken isolates of this virus. We injected turkey poults with the turkey-originating TY89 and chicken-originating BD/6 isolates of IBDV and studied their effects on antibody production to the virus, serum immunoglobulin G (IgG), antibody response to sheep erythrocytes, in vitro response of peripheral blood lymphocytes to mitogens, and microscopic structure of the bursa of Fabricius. The chicken isolate BD/6 caused a significant decrease in the response to sheep erythrocytes, lower serum IgG, transient decrease in the response of lymphocytes to PHA, and mild microscopic lesions in the bursa of Fabricius. The turkey isolate TY89, however, caused no obvious damage to the immune system of the infected poults. We suggest that a partial and transient functional disorder of the immune system of poults can occur after infection with IBDV originating from chickens, even if the poults exhibited no clinical signs.     

Prevalence of Giardia duodenalis infection,co-morbidities and associated risk factors in dogs admitted to a veterinary teaching hospital in Israel

Giardia duodenalis causes gastro-intestinal (GI) disease and carries a zoonotic risk. The risk for infection depends on local prevalence and individual immunity, but clinical signs are inconsistent and the role of G. duodenalis in other GI diseases is unknown. The current study aims were to evaluate the prevalence of G. duodenalis in dogs presented to a university veterinary teaching hospital in Israel, investigate risk factors for infection and its associations with other diseases. Fecal samples from 163 dogs were tested for G. duodenalis by an antigen assay (FASTest® Giardia strip). Prevalence of G. duodenalis infection was 11.9 %. It was significantly associated with young age (≤1year) and canine parvoviral enteritis. Housing conditions, signs of GI disease or other systemic diseases were unassociated with infection. In conclusion, G. duodenalis infection prevalence is relatively low in the study population. Young age and diagnosis of co-infections are common, warranting screening for G. duodenalis.     

Confirmation of the occurrence of the chewing louse Bovicola (Lepikentron) breviceps (Insecta: Phthiraptera: Trichodectidae) on alpacas (Lama pacos) in New Zealand

Abstract

AIM: To investigate the cause of classical swine fever (CSF) virus-seropositive animals in a nucleus pig-breeding herd in New Zealand, where porcine circovirus-associated disease had been diagnosed.

CASE HISTORY AND CLINICAL FINDINGS: An exotic disease investigation was undertaken to exclude CSF and porcine reproductive and respiratory syndrome (PRRS) on a nucleus pig-breeding herd comprising approximately 300 breeding sows, 1,000 weaners, and 650 grower pigs. The herd was experiencing poor reproductive performance in sows, and breeding records showed a declining farrowing rate attributable to a single manager. The growing pigs (10–15 weeks old) were experiencing respiratory disease and wasting, and the mortality rate by pen varied between 9 and 20%. Post-mortem changes in affected grower pigs were consistent with circovirus-associated diseases.

DIAGNOSTIC TESTING: Serological screening using an IDEXX-ELISA gave negative results for PRRS virus antibodies, but two grower pigs and one sow tested positive for CSF virus antibodies. These three seropositive animals remained positive to CSF virus, using three commercial ELISA test kits, over 27 weeks. A newly developed virus neutralisation test (VNT), using a New Zealand isolate of border disease (BD) virus, demonstrated that the seropositive pig sera had higher antibody titres to BD virus than to bovine viral diarrhoea (BVD) virus and CSF virus.

PCR performed on tonsil, kidney, ileum and spleen gave negative results for CSF virus, and histopathology on lymph nodes, intestine, lung, kidney, liver and brain showed no evidence of the disease. Virus isolation performed on a number of samples was negative.

CLINICAL RELEVANCE: The seropositive samples for CSF virus found in this investigation were likely to be a cross reaction to a pestivirus other than CSF virus. The finding of a possible endemic pestivirus capable of being transmitted between sheep and pigs on this farm may explain findings from previous serological survey work in New Zealand, and supports experience elsewhere, where BD virus was found to be the predominant ruminant pestivirus infecting pigs. The results show that pestivirus cross reactivity can result in unexpectedly high titres, and that testing with a full set of (local) pestiviruses is necessary to reach the correct conclusion. The investigation has direct relevance where pig herds with a low seroprevalence are encountered during surveillance for CSF.     

Age-specific seroprevalence of Border disease virus and presence of persistently infected sheep in Basque dairy-sheep flocks

Using p125/p80 antibody and antigen-ELISA tests, age-specific seroprevalence and presence of persistently infected (PI) sheep were investigated in six commercial latxa dairy-flocks, housed for variable periods. The flocks all had a recent history of Border disease (BD). Every flock included seropositive sheep and seven 0.5-3-year-old PI sheep were detected in two of four flocks tested. Age-specific antibody patterns differed according to the presence or absence of PI sheep in the flock. In flocks free of PI sheep, seroprevalence was 6-13% in 1-year-old sheep and 42-93% in older sheep. In contrast, seroprevalence was 67-99% in sheep raised with PI sheep for at least 1 year and 29-33% in replacement 0.5-0.6-year-old sheep (including a PI sheep) indicating that Border disease virus (BDV) transmission in Basque dairy-flocks can be relatively slow. Moderate seroprevalence in young replacement sheep should not discourage further testing to detect PI sheep, and our results highlight the risk of failing to achieve "natural vaccination" prior to pregnancy by mixing PI sheep with BDV-unexposed ewes.