禽白血病的流行病学特点及防制措施

禽白血病是由病毒引起的一种肿瘤性传染病，包括淋巴细胞性白血病、成骨髓细胞性白血病、成红细胞白血病、骨化石病、肝癌、结缔组织瘤等。鸡白血病病毒与肉瘤病毒具有共同的理化特征和群特异性抗原，故放在一个群里。本病在世界各地均有发生，在任何鸡群都有不同程度的存...     

鸡淋巴性白血病的综合防治

鸡白血病是由禽白血病病毒（Avian leucosis viruses，ALV）引起的一种慢性传染性肿瘤病。特征是淋巴细胞瘤化，呈现异常增殖，在全身很多器官中产生肿瘤性病灶。病型可分为四型：淋巴性白血病、成红细胞性白血病、成髓细胞性白血病和骨髓细胞瘤病。基本症状是进行性消瘦，其中以淋巴性白血病最普遍。病鸡的日龄通常在4～10月龄，而自然发病的鸡多发于14周龄以上，到性成熟期发病率最高。传播方式有垂直传播和水平传播两种，主要是垂直传播。     

禽白血病的诊断治疗

禽白血病在临床上有多种表现形式,包括淋巴细胞性白血病、成髓细胞性白血病、血管瘤等,其中以淋巴细胞性白血病最常见。禽白血病在我国广泛存在,对养禽业影响很大。本文对禽白血病的临床综合诊断方法进行了总结,同时也提出了有针对性的防控措施,希望能为广大养殖户提供一定的参考。     

禽白血病的流行病学特点及防制措施

禽白血病是由病毒引起的一种肿瘤性传染病，包括淋巴细胞性白血病、成骨髓细胞性白血病、成红细胞白血病、骨化石病、肝癌、结缔组织瘤等。鸡白血病病毒与肉瘤病毒具有共同的理化特性和群特异性抗原，放同属一个群里。本病在世界各地均有发生，感染率高、发病率低，是危害养鸡业的主要疾病之一。此外，在公共卫生方面也有一定意义，资料表明，禽白血病的感染发生率与人的血癌发生率呈一定的正相关。一、自然宿主与实验后主：鸡是该群病毒的自然宿主，在自然界中鸡广泛发生的是淋巴细胞性白血病（LL），而肉瘤病毒（RSV）的宿主范围最广，…     

J亚群禽白血病的研究进展

禽白血病(Avian Leucosis，AL)是由各种禽白血病亚群病毒引起的多种肿瘤性疾病的总称．主要是以造血细胞恶性增生为主的一类传染病。目前主要将其分为淋巴细胞性白血病、禽骨髓细胞性白血病、成髓细胞性白血病和成红细胞性白血病。其中淋巴细胞性白血病是对禽类危害最大的疾病．相关文献报道亦最多。而骨髓细胞陛白血病(又称禽骨髓细胞瘤Myeloid Leucosis，ML)是由禽白血病病毒J亚群(Avian Leucosis Virus-J subgroup，ALV-J)引起的禽多种肿瘤性传染病。     

鸡白血病的防治

鸡白血病是由禽白血病肉瘤病毒群中的病毒引起的成年鸡的一种慢性淋巴样肿瘤性传染病。有多种病型，如淋巴白血病、成红细胞白血病、成髓细胞白血病、骨髓细胞瘤、肾母细胞瘤、骨石化病、血管瘤等，其中以淋巴白血病（LL）较常见。LL多发于性成熟期的鸡，特征是在肝、     

牛白血病综合症

牛的血淋巴系肿瘤首先起源于淋巴样组织,但肥大细胞白血病与真性红细胞增多也有报告。早期报道的粒细胞性与嗜伊红性白血病可能是肥大细胞白血病的误诊。但粒细胞性白血病据报曾发生在一头4月龄的 Angus 与荷兰牛杂交的处女牛。单核细胞性白血病,可能是恶性淋巴瘤的组织细胞型,偶见于牛,也曾有报告。纤维肉瘤少有报道。白血病综合症在美国及英国广泛地被命名为白血病、恶性淋巴瘤及淋巴肉瘤;但在别处往     

集约化鸡场禽白血病的临床诊断与防控

正禽白血病在我国存在地域广泛,对养禽业影响很大。本文结合多年来的工作经验,对禽白血病的临床综合诊断方法进行了总结,同时也提出了有针对性的防控措施,希望能为广大养殖户提供一定的参考。禽白血病是由禽白血病或肉瘤病毒群中的病毒引起禽类的多种肿瘤性疾病的总称。在临床上有多种表现形式,包括淋巴细胞性白血病、成髓细胞性白血     

从一病例谈对J─亚群白血病的认识

禽白血病是病毒引起流行较广的肿瘤性疾病，感染率很高，临诊上表现形式多样，如淋巴细胞性白血病、成红细胞性的病等，鸡的经典白血病主要是由外源性的Ａ和Ｂ亚群引起，少数由Ｃ和Ｄ亚群引起，Ｅ亚群为内源性病毒，由于内源性白血病病毒基因早在家鸡的祖代已整合到鸡的染色体上，并能随种系繁衍，因此内源性白血病病毒具有很弱的或无致癌特性。所以，根除白血病，通常是指清除外源性白血病病毒感染。多年以来，利用剔除ＡＬＶ感染种鸡以切断垂直传播的方法，到了八十年代中期，在世界发达国家的种鸡群中已基本消灭了这类经典的外源性ＡＬＶ…     

养禽业面临着新威胁──禽骨髓性白血病

目前，全球的养禽业正在遭受着一种新的禽白细胞增生病病毒的侵袭。这种刚被检测到的病毒现已被定为Ｊ亚型。由于它通常只侵袭骨髓单核细胞（骨髓性白细胞），而很少侵袭淋巴性白细胞，因而这种亚型引起的疾病称禽骨髓性白血病。它在肉种鸡中流行较为广泛，有的肉种鸡群感染率高达５０％，因此引起了世界五大肉鸡育种公司的高度重视，并联手研究控制措施，以免造成更大损失。一、病原禽骨髓性白血病病毒（ＡＬＶ－Ｊ）是一种反转录病毒属病毒，此病毒是一外源性白血病病毒与一内源性Ｅ亚群的囊膜基因重组体，有一个蛋白质成分的核衣壳。ＡＬ…     

Application of a radioimmunoassay for detection of the major internal antigen (p24) of bovine leukemia virus from cultured lymphocytes of cattle

A sensitive and specific radioimmunoassay for the major internal antigen of bovine leukemia virus has been applied to detecting this protein in cultured lymphocytes of infected cattle. The specificity inherent in this assay offers obvious advantages over a previously described syncytium induction assay for infectious bovine leukemia virus, because false positive reactions due to other viruses such as bovine syncytial virus are avoided. Investigations of various culture conditions indicated that maximal amounts of antigen had been produced after incubation for 72 hr at 37°C. Lymphocyte concentrations of 10⁶?5×10⁷ cells/ml gave satisfactory results. Tests of cultured lymphocytes from bovine leukemia virus infected or bovine leukemia virus-free cattle indicated a comparable sensitivity between the radioimmunoassay and syncytium induction assay in the detection of bovine leukemia virus infections.     

Retroviral-associated eosinophilic leukemia in the cat

Fourteen specific-pathogen-free cats were inoculated with a putative env gene recombinant feline retrovirus, PR8. An isolate of the Rickard strain of feline leukemia virus (FeLV-R), PR8, has the properties of both an exogenous (FeLV-R) and an endogenous (xenotropic) feline retrovirus (RD-114). Twelve of the PR8-inoculated cats developed viremia; 2 of the 12 cats developed eosinophilia, with 1 being diagnosed with eosinophilic leukemia and the other with extreme eosinophilic hyperplasia. Eosinophilic leukemia is rare in cats and has not previously been associated with retroviral infection. Changes in the viral envelope properties may have altered the pathogenicity of the exogenous virus to cause this rare form of leukemia.     

Inhibition of Feline leukemia virus replication by the integrase inhibitor Raltegravir

The oncogenic gammaretrovirus Feline leukemia virus (FeLV) has been the leading cause of death among domestic cats until the introduction of efficient diagnostics and vaccines in the late 1980s. So far, no efficient treatment for viremic animals is available. Hence, use of the FeLV model to evaluate antiretroviral therapies applied to HIV is a timely task. The efficacy of the integrase inhibitor Raltegravir, which is widely used for the treatment of HIV in humans, has been assessed in vitro for the FeLV-A/Glasgow-1 strain. EC(50) values for FeLV-A inhibition in feline cell lines are in the range of that observed for HIV and xenotropic murine leukemia virus-related gammaretrovirus. Therefore, Raltegravir may be a potential therapeutical agent for felids with progressive FeLV infection.     

Histology of the salivary gland of two leukotic cats

Feline leukemia (leukosis, lymphosarcomatosis) is now known to be caused by a virus (Jarrett et al. 1964). The feline leukemia virus antigen has been demonstrated in salivary glands of leukemic cats (Hardy et al. 1969, 1970) and according to Gardner (1971) the C-type virus particles will replicate in the salivary glands of leukotic cats.     

Levamisole does not affect the virological and serological responses of bovine leukemia virus-infected cattle and sheep.

Levamisole, a compound that has been used widely as an anthelmintic in man and domestic animals, has also been found to be an immunomodulator. It was, thus, of interest to determine whether treatment with levamisole would affect bovine leukemia virus infections in cattle and sheep or the results of serological and virological tests routinely used to identify infected animals. Studies of cattle and sheep given either the recommended anthelmintic dose of levamisole or repeated larger doses of the drug failed to provide evidence of significant changes in antibody titer or virus replication. It is, therefore, concluded that levamisole neither potentiated nor repressed bovine leukemia virus replication or the associated immunological responses.     

Acute lymphocytic leukemia in a six-month-old western lowland gorilla (Gorilla gorilla gorilla).

A 6-mo-old hand-raised male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed with acute lymphocytic leukemia based on complete blood count and bone marrow cytology. Clinical signs of the disease were pyrexia, abdominal distention, splenomegaly, and lethargy. Acute lymphocytic leukemia has rarely been reported in this species, and therapy was based on human oncologic protocols. Remission induction chemotherapy resulted in complete clearing of leukemia cells from the bone marrow. Consolidation and maintenance chemotherapy followed. Therapy was facilitated by the use of an infusion port for i.v. treatments and an indwelling lumbar catheter for intrathecal therapy. Side effects associated with chemotherapy were inappetence, moderate alopecia, pancytopenia resulting in sepsis, and bleeding tendency. In spite of initial success, the leukemia reappeared 120 days into treatment. The gorilla was euthanized 7 days later when respiratory distress developed. Intensive care by the animal staff was a key factor in the treatment of this gorilla.     

T-cell lymphoproliferative disorder in an aged rhesus macaque

A CD8+ T-cell leukemia was diagnosed in an aged female rhesus macaque. Although leukemia and lymphoma in nonhuman primates are commonly associated with simian T-lymphotropic virus, gibbon ape leukemia virus, oncogenic herpesviruses, and types C, D, and E retroviruses, this monkey was not infected with any of these viruses. However, the monkey did have antibodies against herpesvirus saimiri. This likely represents cross-reactivity of the herpesvirus saimiri assay with rhesus monkey rhadinovirus (RRV) antibodies; RRV was first described in rhesus macaques that were identified as having antibodies against herpesvirus saimiri. Rhesus rhadinovirus is a gamma herpesvirus, related antigenically to herpesvirus saimiri and Kaposi's sarcoma-associated herpesvirus (KSHV), which have been linked to lymphoproliferative disorders in primates and humans, respectively. Moreover, an oncogene has been recently identified in the RRV genome that is equivalent in position to the herpesvirus saimiri and KSHV oncogenes. Presently, the association of RRV infection with disease in nonhuman primates is unknown.     

Immunomodulation of hematopoietic tumors

Immunotherapy has been used in a variety of hematopoietic and solid tumors. Because patients with leukemia and lymphoma are immunosuppressed, immunomodulation with chemotherapy may be beneficial. Chemoimmunotherapy of canine lymphoma is discussed.     

A strategy for control of bovine leukemia virus infection: test and corrective management

Test and corrective management was applied in one dairy herd (130 milking cows) to control bovine leukemia virus infection. It consisted of: raising uninfected calves in order to establish a pool of uninfected replacement heifers, preventing transmission of bovine leukemia virus through transfer of blood from animal to animal and closing the herd. Regular herd testing was combined with selected changes in herd management. These procedures have been followed since January 1979. Prevalence of antibodies (as determined by gel-immunodiffusion) has declined markedly since the program was implemented.     

A microculture syncytia assay for bovine leukemia virus

A microculture syncytia assay for the detection of bovine leukemia virus (BLV) has been described and compared with the conventional macroculture assay. The microculture assay required fewer indicator cells, was as sensitive as the macroculture assay and provided a reproducible test for the detection and titration of BLV.