Sero-survey on Aino, Akabane, Chuzan, bovine ephemeral fever and Japanese encephalitis virus of cattle and swine in Korea

Vector-borne arboviruses produce mild to severe symptoms in domestic animals. Bovine ephemeral fever (BEF), Akabane, Aino, and Chuzan virus have been primarily attributed to reproductive disorders or febrile diseases in cattle, and Japanese encephalitis virus (JEV) is mainly associated with reproductive failures in swine. We investigated antibody titers from domestic swine against four bovine arboviruses (BEF, Akabane, Aino, and Chuzan virus) and from cattle against JEV in Korea. While the positive rates for Akabane and BEF were 37.4% and 15.7%, the positive incidence of Chuzan and Aino were relatively low, with positive rates of 3.04% and 0.4%, respectively, based on a virus neutralization assay. Antibody titers against more than one virus were also frequently detected in domestic swine. The incidence of JEV was 51.3% among domestic cattle. In addition, one positive case was detected in the thoracic fluids from 35 aborted calves, based on the hemagglutination inhibition test. Our results indicate that swine are susceptible hosts of bovine arboviruses without showing clinical symptoms in a natural environment. Moreover, we confirmed that JEV could be associated with reproductive failure in pregnant cattle, as were other vector-borne bovine arboviruses assessed in this study.     

Acute Atypical Bovine Pneumonia Caused by Ascaris Lumbricoides

A case of acute atypical pneumonia (bovine asthma, pulmonary emphysema, or pulmonary adenomatosis) occurred in a group of cross-bred beef type yearlings in late autumn. Clinical signs included a forced expiratory grunt, excessive salivation, ruminal stasis and, on auscultation over the lungs, pulmonary emphysema and oedema. The cattle had been brought in from a poor summer pasture and housed in a pig pen heavily contaminated with Ascaris lumbricoides eggs as it had contained unwormed feeder pigs all summer.

Fifteen out of seventeen head were affected ten days following housing and all within twenty-four hours. One steer of the group died and at necropsy fourth stage A. lumbricoides larvae were isolated from lungs showing profuse oedema and some emphysema. Histopathological examinations of the lungs showed a diffuse interstitial pneumonia. All remaining animals appeared clinically normal six days following the outbreak.

     

Pulmonary edema and emphysema in cattle after intraruminal and intravenous administration of 3-methylindole.

Intraruminal and intravenous administration of 3-methylindole (3MI; skatole) caused interstitial pulmonary edema and emphysema in cattle. In 3 adult heifers given the intraruminal dose of 0.2 g of 3 MI per kilogram of body weight, clinical signs of respiratory disease appeared between 6 and 12 hours after dosing, and death due to pulmonary edema and emphysema occurred at 33, 69, and 72 hours. The mean plasma concentration of 3MI became maximal (18.5 mug/ml) at 3 hours and then decreased to low concentrations by 48 hours. In 2 heifers given an intraruminal dose of 0.1 g of 3MI/kg, clinical signs developed, but they did not die during the 96-hour experiment. The mean plasma concentration of 3 MI became maximal (16.8 mug/ml) at 3 hours and decreased to 1.6 and 0.4 mug/ml at 12 and 36 hours, respectively. At necropsy of the heifers, the lung were large, firm, dark red, and heavier than normal. Diffuse pulmonary edema was the predominant change in cattle which died early, and interstitial emphysema was more severe at later stages of the disease. During the early stages, alveoli were overdistended, and a few more ruptured. Most alveolar spaces were filled with proteinaceous residue, but the alveolar septums were smooth and of normal thickness. At later stages, proliferation of alveolar cells was observed, and alveolar septums were thickened. In 3 cows given 0.06 g of 3MI/kg by jugular infusion, clinical signs appeared in all cows, and 1 cow died of pulmonary edema and emphysema 56 hours after the infusion was started. Severe pulmonary lesions seen in all of the cows given a 3MI infusion were similar to those in the cows given an intraruminal dose of 3MI. The mean plasma concentration of 3MI increased to 10.7 mug/ml at 9 hours after starting the infusion and decreased to 0.5 mug/ml at 18 hours. The results indicate that 3MI, a product of ruminal tryptophan fermentation, can cause pulmonary edema and interstitial emphysema in cattle and support the hypothesis that 3MI is the causative agent in tryptophan-induced pulmonary disease.     

The effect of anti-inflammatory agents on the clinical expression of bovine ephemeral fever

The effect of two anti-inflammatory drugs on the development and persistence of clinical signs in cattle experimentally infected with bovine ephemeral fever (BEF) virus was investigated by their administration, either before or after the commencement of fever. A total of 16 cattle was given phenylbutazone sodium (PBZ). The drug prevented fever and other clinical signs in six cattle when given daily during the incubation period, and at 8-h intervals for 5 days when clinical disease might be expected. When treatment with PBZ was deferred until 2-4 h after the commencement of fever, the rectal temperature returned to normal within 4 h in four of six cattle and the development of other clinical signs was suppressed. Clinical signs of ephemeral fever occurred in four untreated cattle infected at the same time. Viraemia, the development of neutralizing antibodies (at 8-11 days), resistance to subsequent challenge with BEF virus, neutrophilia, lymphopenia and a rise in plasma fibrinogen occurred in all BEF-infected animals whether treated or untreated, despite different clinical appearances. The mean peak of plasma fibrinogen in the untreated cattle was 6.9 g l-1; 3.2 g l-1 when treated 2-4 h after fever developed and 3.8 g l-1 when treated from 18-h post-infection. BEF virus was isolated from leucocytes of each of the cattle, but the frequency of isolation was lower in the treated group. The results indicate that treatment with PBZ blocked the host response which produces the clinical signs and did not have an anti-viral effect. In a similar experiment, a long-acting anti-inflammatory drug, flunixin meglumine, failed to prevent BEF or to modify the clinical signs once they had developed, except for the rectal temperature which returned to normal within 2-4 h of the administration of the drug. The efficacy of this drug was not improved by increasing the dosage to two or three times the recommended level.     

An outbreak of bovine ephemeral fever in Nagasaki Prefecture in 1988

In October, 1988, bovine ephemeral fever (BEF) occurred in Nagasaki Prefecture and throughout Kyushu island, with the exception Miyazaki Prefecture. The first outbreak occurred in Hirado-shi on October 17. The total number of diseased cattle was 24 in 24 farms in Nagasaki Prefecture. The clinical findings were mainly sudden fever, anorexia, and instability in standing. The serum neutralizing antibodies against BEF virus (BEFV) rose in all infected cattle. Twelve strains of the virus were isolated in HmLu-1 cell cultures made directly from the heparinized blood of 17 infected cattle. The buffy coat was mainly collected from the samples and washed three times with phosphate buffered saline. These isolates were all neutralized by an antiserum against BEFV (Yamaguchi strain). With the aid of an electron microscope, a representative of isolates named Hirado-9 with a length of 150 nm was seen in the sample of infected HmLu-1 cell cultures. Both Hirado-9 and Yamaguchi strains reacted with antisera. The outbreak of BEF in 1988 was the first since 1971 in Nagasaki Prefecture. The result proved that BEFV can be easily isolated in HmLu-1 cell culture from the washed blood cells of infected cattle.     

Theoretical epidemiology on bovine ephemeral fever outbreaks in Tanegashima Island, Kagoshima Prefecture of Japan in 1988.

From the end of September to November 1988, a compact scale of bovine ephemeral fever (BEF) outbreaks occurred suddenly in Tanegashima island of Kagoshima Prefecture, southern part of Kyusyu island of Japan. The BEF outbreak pattern showed epidemical characteristics as follows; (1) outbreak spread from few foci to zone during one month, and (2) the disease might be transmitted in farms with a fixed probability of adequate contact. By using the above aspects, we attempted to analyze the disease theoretically with the application of Poisson distribution and Reed-Frost model. The BEF incidence in farms was in well accord with the Poisson distribution. As the very rare event occurred in unit time or in unit area in this epidemic, the cattle population at risk were equivalently susceptible to BEF virus in this island, due to the influence of no vaccination to BEF control before the first outbreak. Similarly, the epidemic curve of the Reed-Frost model was proved to fit well the incidence observed in a farm, and the probability of adequate contact was induced as p = 0.226. If the cattle population is less than 5 in this farm, the outbreak would not occur in the first instance.     

Homologous and heterologous antibody reactions in sera from cattle naturally infected with bovine ephemeral fever group viruses

Four viruses belonging to the bovine ephemeral fever (BEF) group have been isolated from bovine blood. Infection of cattle with BEF virus was associated with neutralizing antibody responses to BEF, Kimberley (KIM), Berrimah (BRH) and Adelaide River (ADE) viruses, with highest antibody titres to BEF and KIM viruses. Infection of one cow with KIM virus was associated with a homologous neutralizing antibody response and nil or minimal responses to the other three viruses. Infection of a steer with ADE virus was associated with a rise in neutralizing antibody levels to ADE virus and to KIM virus, but not to BEF or BRH viruses. Infection of a steer with BRH virus was associated with marked neutralizing antibody rises to BRH and BEF viruses and small rises to KIM and ADE viruses. An antibody rise to BEF virus did not necessarily indicate recent BEF virus infection, and should be considered of diagnostic value only when taken in conjunction with clinical signs of disease.     

The relationship between selenium deficiency and the development of pulmonary and subcutaneous emphysema in bovine ephemeral fever virus-infected cattle

Bovine ephemeral fever (BEF) was diagnosed on several commercial farms around Harare, Zimbabwe. The affected animals showed signs of fever (40-41.5 degrees C), depression, ruminal stasis, lameness and recumbency. Eight of those attended had severe respiratory distress and subcutaneous emphysema. Haematological and biochemical results indicated leukocytosis with an attending lymphopaenia. Selenium deficiency was detected only in those animals which showed respiratory embarrassment and subcutaneous emphysema.     

The isolation and preliminary characterization of a rhabdovirus in Australia related to bovine ephemeral fever virus

CSIRO 368 virus was isolated from blood collected in the Northern Territory from a healthy cow and electron microscope studies showed that the isolate had rhabdovirus morphology. Fluorescent antibody studies and complement fixation tests related the virus to bovine ephemeral fever (BEF) virus. Neutralization tests in both suckling mice and Vero cells showed that the virus was not BEF virus. Antibodies to CSIRO 368 virus were found in cattle sera from northern and eastern Australia and Papua New Guinea. Antibodies were found in 16 out of 45 buffalo, some of which also had antibodies to BEF virus. In contrast, none of the 419 deer tested had antibodies to CSIRO 368 virus, although 142 of the same deer had antibodies to BEF virus. No antibodies to CSIRO 368 virus were detected in 16 goats, 54 horses, 10 pigs, 31 sheep, 25 kangaroos, or 14 human beings. Both CSIRO 368 and BEF viruses were found to be sensitive to ether and chloroform, but were not affected by the DNA inhibitor 5-bromo-2'-deoxyuridine, showing that they probably had the same type of nucleic acid--namely RNA. CSIRO 368 was also shown to grow to higher titres in BHK21 cells than in Vero cells. Temperature sensitivity studies at -20, 4 and 37 degrees C showed that the presence of foetal calf serum increased the survival time markedly at -20 degrees C, but only slightly at 4 and 37 degrees C. The virus survived the longest at -20 degrees C in the presence of foetal calf serum.     

An epizootic of bovine ephemeral fever in New South Wales in 2008 associated with long-distance dispersal of vectors

Objective To report the rapid transmission of bovine ephemeral fever ( BEF) virus from north-western New South Wales south to the Victorian border in January 2008 and to present data that suggests an uncommon meteorological event caused this rapid southward dispersal of vectors. Procedure The locations of reported clinical cases, data from sentinel herds and results from a survey of cattle in the southern affected area were examined to delineate the distribution of virus transmission. Synoptic weather charts for January 2008 were examined for meteorological conditions that may have favoured movement of vectors in a southerly direction. Results Cases of BEF and exposure to BEF virus in NSW were confirmed west of the Great Dividing Range, extending from the Queensland border to Finley, on the far North Coast and around the Hunter Valley. A low-pressure system moved south across the state on 18–19 January 2008, preceding the first cases of BEF in the south of NSW by 1–2 days. Conclusion Heavy rainfall in December 2007 provided a suitable environment for vector breeding, resulting in the initiation of and support for continuing BEF virus transmission in north-western NSW. The movement of a low-pressure system south across central western NSW in mid-January 2008 after the commencement of BEF virus transmission in the north-west of the state provided a vehicle for rapid southward movement of infected vectors.     

An experimental inactivated virus vaccine against bovine ephemeral fever 2. Do neutralizing antibodies protect against infection?

In order to develop a safe vaccine against bovine ephemeral fever (BEF) which could be used in areas normally free of the disease, studies were carried out on inactivated virus vaccines. Initial experiments were carried out in cattle using virus vaccines that had been inactivated with β-propiolactone or formalin and then made-up in aluminium phosphate gel or Freund's incomplete adjuvant. A minimum inactivated virus dose of 10⁶ PFU was necessary to stimulate a serum neutralizing antibody response in cattle. β-propiolactone inactivated BEF virus vaccines in Freund's incomplete adjuvant gave the best serum neutralizing antibody responses, producing high levels of neutralizing antibody with both high and low passage level virus. However, the magnitude of the antibody response bore little relationship to resistance of vaccinated animals to challenge with virulent BEF virus. A number of animals with high neutralizing antibody titres to BEF virus did not resist challenge. Using 500-fold less live virus at equivalent passage level to the low passage inactivated vaccine, similar or slightly lower antibody levels were attained, but most of the animals resisted challenge. It is suggested that the nature of the immune response and resistance to BEF infection may be complex and that reliance on serum neutralizing antibody as an indicator of resistance may give misleading results.     

一例体细胞克隆黄牛肺脏的组织结构观察

作者应用石蜡切片及HE染色技术对体细胞克隆黄牛的肺脏及其细胞类型和形态进行了详细的观察。结果表明,光镜下,该体细胞克隆黄牛肺脏的组织结构与自然繁殖的黄牛肺脏的组织结构基本一致,包括支气管、细支气管、终末细支气管、呼吸性细支气管、肺泡管、肺泡囊及肺泡等结构,但体细胞克隆黄牛的细支气管管壁内的皱壁消失,其黏膜以单层立方上皮为主;肺泡处于半充容状态,肺泡腔狭小,肺泡膈较厚,其中含有较多胶原纤维和弹性纤维。肺泡壁的细胞结构不清,肺泡腔内有内容物,可能是发生病变引起。     

Transmission of virus from serosal fluids and demonstration of antigen in neutrophils and mesothelial cells of cattle infected with bovine ephemeral fever virus

Following intravenous injection of bovine ephemeral fever (BEF) virus 6 cattle were autopsied after clinical disease became evident. Fluid from serosal cavities with serofibrinous inflammatory changes showed large increases in neutrophil numbers. BEF virus was detected for the first time in pericardial, thoracic and abdominal fluids. Virus was also detected in synovial fluids, confirming an earlier report of transmission with a synovial fluid sample. Using a direct fluorescent antibody technique, BEF virus antigen was identified for the first time in synovial, pericardial, thoracic and abdominal fluids, in synovial membranes and epicardium. In synovial membranes and epicardium, specific fluorescence was observed in two cell types, mesothelial cells and neutrophils. In the fluids, fluorescence was restricted to neutrophils, the predominant cell type. Specific fluorescence was observed in blood smears from only one animal although blood samples collected at autopsy from all animals contained infective virus.     

LABORATORY AND FIELD STUDIES WITH A BOVINE EPHEMERAL FEVER VACCINE

Bovine ephemeral fever (BEF) virus vaccines, prepared from the brains of suckling mice infected with strain 525 BEF virus, were evaluated in housed cattle and in the field. The virus in lyophilised preparations was stable for 6 months at -50 degrees C. Thirty-four calves, 5 to 18 months old, were used in laboratory vaccination trials. An increase in serum neutralising antibody was detected in 13 of 14 calves initially free of serum antibody, and all 13 failed to develop clinical illness following challenge with virulent BEF virus. Vaccination resulted in no detectable serum antibody increase in 4 calves, 5 months old, with pre-existing antibody of presumed maternal origin. Seven animals, 18 months of age with serum antibody presumed due to previous BEF infection, developed increased antibody titres following vaccination. In 3 animals vaccinated but not challenged, vaccine-induced antibodies decreased to low levels over 5 months. In contrast, the antibody titres following infection with virulent virus in 2 calves were maintained over 5 months. Field trials, involving 236 animals initially free of serum antibody, were conducted on 5 properties near Mackay and 4 properties near Brisbane. Most of 164 animals were vaccinated with a single dose of lyophilised vaccine containing aluminium hydroxide adjuvant. Only 4 animals failed to develop serum antibody and no adverse reactions to vaccination were reported. Natural infection with BEF occurred in 4 herds at Mackay and clinically mild BEF occurred in 3 of 109 vaccinated and 3 of 46 control animals. On the basis of measured serum antibody titres it was assumed that 8 of 53 animals receiving full vaccine volume, 20 of 40 animals receiving half vaccine volume and 18 of 40 control animals became infected with BEF virus. Two dairy herds in Brisbane became naturally infected with virulent BEF virus 7 months after vaccination. Clinical BEF was observed in 8 of 11 control animals and in 3 of 26 animals which received 2 doses of vaccine. Two strains of BEF virus were isolated from unvaccinated animals that developed clinically mild BEF in the field. These strains either failed to infect, or produced subclinical or very mild BEF, when inoculated intravenously into susceptible calves. The anitbody response to natural infection with apparently mild viruses was short-lived, similar to that produced by vaccination.     

Retrospective epidemiological investigation of an outbreak of bovine ephemeral fever in 1991 affecting dairy cattle herds on the Mediterranean coastal plain

From August to October 1991 bovine ephemeral fever (BEF) occurred sporadically in two localities in Israel. The morbidity and mortality rates reached 2.6% and 0.1%, respectively. Only 12/50 dairy cattle herds were clinically infected with BEF in the dairy community. The total morbidity rate reached 0.8%. The lowest morbidity rate was recorded in young heifers (5.5%) and the highest in adult cows (75%). Only heifers over the age of three months were clinically affected. The spread of the disease apparently followed the local prevailing night winds, which blow from east to west, i.e., from the land toward the sea. The morbidity period lasted 61 days. The low incidence and morbidity rates were possibly due to the low virulence of the virus strain involved in the 1991 epidemic. Retrospective analysis indicates that vectors - apparently mosquitoes - infected with BEF virus could have been overwintering.     

牛暂时热研究进展

牛暂时热是一种发生于热带与温带地区牛的急性、免疫病理性病毒病，包括蚊、蠓在内的多种昆虫参与了该病的传播。本文就BEFV的病原学、流行病学、传播、防制、研究进展及研究趋势做了综述。     

Impairment of sympathetic pulmonary vasoconstriction by 3-methylindole in cattle

Sixteen Holstein cattle allotted into 4 groups (4 cattle/group) were each given a single oral dosage of 0.2 g of 3-methylindole (3MI)/kg of body weight. The groups were killed at 12, 24, 48, and 72 hours, respectively, after 3MI administration. Comparison of clinical signs, pathologic pulmonary lesions, and in vitro pulmonary artery responses to pharmacologic stimuli was made between the 4 treated groups and 8 control Holstein cattle of similar age. Clinical signs of pulmonary distress first appeared 8 to 12 hours after 3MI administration. After 20 hours, clinical signs included dyspnea, moderate depression, and a marked expiratory grunt. A partial remission of these clinical signs was seen between 30 and 45 hours after 3MI administration. After remission, the cattle had clinical signs of severe dyspnea and depression and expiratory grunts were more pronounced. Pathologic pulmonary lesions, including heavy rubbery lungs, dilated interlobular septae, and subplural air bullae characteristic of pulmonary edema and interstitial emphysema were observed. The lungs of treated cattle did not collapse when the thorax was incised at necropsy. In vitro pulmonary artery strips contracted dose dependently to norepinephrine (NE). Group I tissues (12 hours after 3MI administration) responded similarly to control samples. Group II tissues (24 hours after 3MI administration) had a significant inhibition (P less than 0.05) in response to NE stimulation as compared with controls.     

牛流行热研究进展

牛流行热,又称为三日热,是由虫媒弹状病毒牛流行热病毒(BEFV)引起的牛和水牛的一种传染病.该病会导致牛发热、四肢僵硬、跛行,通常又会完全恢复.其会引起感染动物的死亡,母牛流产,致使奶牛产奶量下降、公牛体重和生殖能力下降.作者结合国内外对牛流行热病毒的研究,从发病历史、流行病学、病原学、临床症状、致病机理、诊断、防控等方面阐述了牛流行热的研究进展,旨在为该病的深入研究提供参考.     

Ruminal and plasma concentrations of 3-methylindole associated with tryptophan-induced pulmonary edema and emphysema in cattle.

Five Hereford cows were given an intraruminal dose of L-tryptophan (0.35 g/kg of body weight), and 2 cows were used as controls. Of the 5 treated cows, 3 developed clinical signs of interstitial pul monary edema, and emphysema and severe pulmonary lesions were seen at necropsy after 96 hours. Another cow developed moderate clinical signs and pulmonary lesions, and the remaining cow had few clinical signs and mild pulmonary lesions. The severity of clinical signs in each cow was related to the severity of pulmonary lesions at necropsy. The 3-methylindole (3MI) was present in ruminal fluid and plasma within 6 hours after administration of tryptophan, and the concentrations increased to 3.0 and 9.0 mug/ml within 12 to 24 hours. Severity of pulmonary lesions was related to maximal concentration and duration of 3MI in the plasma. At necropsy, gross lesions were characterized by diffuse, pulmonary edema and interstital emphysema; and the lungs were dark red, firm, and heavier than normal. Predominant microscopic changes included accumulation of proteinaceous residue, hypertrophy and hyperplasia of alveolar lining epithelium, thickening of alveolar septums, and emphysematous thickening of interstitial tissues. These changes were similar to previously reported 3MI-induced pulmonary lesions. The presence of 3MI in ruminal fluid and plasma after administration of tryptophan and the relationship between concentration of 3MI and severity of clinical signs indicate that 3MI is the principal metabolite of ruminal fermentation which leads to the development of acute pulmonary edema and emphysema in cattle given tryptophan.     

Scanning electron microscopic study of the lower respiratory tract in calves and adult cattle

The surface characteristics of the lower respiratory tract of two groups of cattle were studied with the scanning electron microscope. Group A comprised six one-week-old calves and group B four adult cows. None of the animals had overt respiratory disease or gross morphological evidence of pulmonary lesions. The trachea, bronchi, bronchioles and alveoli of the cranial and the caudal lobes of the right lung were examined. In both groups the luminal surface of the trachea and large bronchi were completely covered by cilia, apparently forming an efficient mucociliary escalator. In the adult animals there were some patchy areas in the trachea and large bronchi devoid of ciliated cells; these were considered abnormal. In the bronchi, non-ciliated cells, mainly mucus-secreting, were not easily identified unless they were discharging secretion. In small bronchi, non-ciliated cells were more evident and easily seen. The bronchioles had many non-ciliated cells and very few ciliated cells capable of forming a complete carpet for a mucociliary escalator. Types 1 and 2 alveolar epithelial cells and alveolar macrophages were identified in both groups. Pores of Kohn were found in the alveolar walls in all animals.