江苏安徽两省鸭疫里默氏杆菌病的流行病学调查研究

1996年1月至2001年6月，对江苏、安徽两省86个鸭场的发病鸭从日龄、品种、流行季节、流行菌株的血清型以及血清流行病学等方面进行了鸭疫里默氏杆菌病的调查。结果，在57个鸭场的樱桃谷鸭、番鸭及野鸭体内分离到鸭疫里默氏杆菌92株，而从麻鸭的病料中未分离到该菌；分离到病原的鸭最小为12日龄，最大为41日龄，主要集中在12－30日龄；这些地区鸭疫里默氏杆菌病的流行无明显季节性；这些地区鸭场疫里默氏杆菌流行菌株的血清型至少有5个，其中1、2和10是流行株的主型。     

血清15型鹅源鸭疫里默氏杆菌的分离鉴定及交叉免疫保护研究

本研究对安徽省某鹅场急性死亡的雏鹅进行了细菌分离鉴定,无菌采集病死鹅肝脏、脑和心包液,经过培养特性观察、染色镜检、生化特性检测以及16S rRNA和血清学检测,鉴定病原菌为血清15型鸭疫里默氏杆菌,命名为LAG1株。该分离菌株对四环素类药物敏感,而对卡那霉素等耐药;对雏鸭的致病性强,半数致死量(LD50)测定为7.75×103CFU/只;交叉免疫保护试验结果显示LAG1灭活油乳剂疫苗对自身菌株攻毒的免疫保护率可达80%以上,对血清10型鸭疫里默氏杆菌HXb2攻毒的保护率可达70%,对血清1型鸭疫里默氏杆菌WJ4和血清2型鸭疫里默氏杆菌Yb2攻毒的保护率低于20%。本研究结果可为安徽省养鹅业鸭疫里默氏杆菌病的防治工作提供参考。     

科技动态

血清1型鸭疫里默氏杆菌灭活油乳剂疫苗的研制为研究血清1型鸭疫里默氏杆菌(R.anatipestifer,RA)的灭活油乳剂疫苗,中国农业科学院上海兽医研究所丁铲等将10株血清1型RA的临床分离株经腿部肌肉注射7日龄雏鸭进行动物体内复壮,结果表明所有被     

血清1型鸭疫里默氏杆菌灭活油乳剂疫苗的研制

为研究血清1型鸭疫里默氏杆菌(R.anatipestifer,RA)的灭活油乳剂疫苗,本研究将10株血清1型RA的临床分离株经腿部肌肉注射7日龄雏鸭进行动物体内复壮,结果表明所有被测菌株均具有较强的毒力,易感雏鸭致死率100％.对其中3株RA分离株CH3、WJ4和YL4的毒力测定结果表明其半数致死量(LD50)分别为2×108 cfu、3.25×108 cfu和2.37×106 cfu.选取5株RA分离株分别制备灭活油乳剂疫苗,分别于5日龄和18日龄对樱桃谷鸭进行两次免疫后,免疫鸭能够产生高水平的RA特异性抗体,对2 LD50 WJ4或CH3攻毒产生很好的保护效果,其中由CH3、CQ3和YXb12制备的灭活油乳剂疫苗对攻毒的保护率高达100％.     

鸭疫里默氏杆菌病病原分离鉴定与血清抗体检测

湖北某鸭场10日龄雏鸭发生疑似鸭疫里默氏杆菌病,观察其临床具有神经症状,剖检具有心包炎、肝周炎和气囊炎等典型病变。无菌采集发病鸭脑组织进行细菌分离,并取血清进行抗体检测。分离菌经过菌落形态、染色形态、PCR以及血清学鉴定为Ⅰ型鸭疫里默氏杆菌,血清OmpA-ELISA抗体反应呈阳性。15种抗生素的药敏试验结果显示分离菌对萘啶酸等喹诺酮类药物耐药,对头孢曲松等头孢类药物高度敏感,结果为鸭疫里默氏杆菌病防控提供依据。     

鸭疫里默氏杆菌对肉鸭感染性试验

选择川渝地区流行的鸭传染性浆膜炎病原鸭疫里默氏杆菌(RA)的主要血清型中的强毒力株AF株作为攻毒菌种。菌种液通过接种巧克力培养基进行复苏,检验合格后,在无菌工作台内用无菌生理盐水洗下菌苔,制成2.4×109CFU/ml(A600=0.65)的菌悬液,对不同日龄花边肉鸭攻毒,观察记录发病率、死亡率、剖检症状、回收细菌,并鉴定血清型。结果表明,8、18日龄是AF株RA感染花边肉鸭的最敏感日龄,发病率为100%,死亡率为90.9%。     

河北故城地区鸭疫里默氏杆菌的分离鉴定和血清型分析

对河北省故城地区送检的疑似鸭疫里默氏杆菌感染发病的病鸭进行病原菌的分离鉴定,根据培养特性和生化鉴定结果鉴定出13株鸭疫里默氏杆菌,并对分离菌进行了血清型鉴定和药物敏感试验;经玻片凝集试验和琼脂扩散试验得出血清1型5株,血清2型4株,血清6型1株,血清10型1株,还有2株未定型。试验证明血清1、2型是目前故城地区鸭疫里默氏杆菌的主要流行血清型,分离菌株对雏鸭有很强的致病性且耐药谱较广,但对氧氟沙星、盐酸恩诺沙星和氟苯尼考较为敏感。     

血清2型鸭疫里默氏杆菌制苗用菌株的筛选及灭活油乳剂疫苗的研制

血清2型鸭疫里默氏杆菌(Riemerella anatipestifer,RA)分离株经雏鸭体内复壮、回收、鉴定后,选取其中2株细菌NJ3和Yb2进行毒力测定,结果表明其半数致死量分别为5.62×107CFU和1.07×105CFU。选取5株细菌制备灭活油乳剂疫苗后免疫鸭,并进行攻毒保护试验。结果表明不同菌株制备的疫苗均可使免疫鸭产生高水平的RA特异性ELISA抗体和攻毒保护力,但是攻毒保护性差异较大,NJ3免疫后的攻毒保护性最好。抗体检测及攻毒保护实验表明NJ-3是较理想的制苗用菌株。     

Ⅰ型鸭疫里默氏杆菌的分离与鉴定

从扬州仪征某樱桃谷肉鸭鸭场病死鸭的肝、脾、脑、心血中分离到9株细菌,经对分离菌进行染色、形态观察、生化鉴定及凝集试验,其中5株鉴定为Ⅰ型鸭疫里默氏杆菌（Rimerella anatipestifer,RA）。经动物回归试验,表明该菌对雏鸭有较强的致病力。     

一株肉种鸡源鸭疫里默氏杆菌分离鉴定及致病性研究

为探究鸭疫里默氏杆菌对鸡的致病力,试验采集疑似感染鸭疫里默氏杆菌的病死肉种鸡肝脏进行病原的分离培养与纯化、革兰氏染色、生化试验、血清型鉴定、16S rRNA基因测序分析及药敏试验,并将分离菌株在SPF鸡、樱桃谷鸭上进行致病性试验。结果显示：分离到1株血清1型鸭疫里默氏杆菌,该菌株与鸭源、鸡源、鹅源鸭疫里默氏杆菌的相似性分别为99.24%～99.47%、99.16%～99.31%、99.04%～99.20%;该分离株对恩诺沙星、卡那霉素、头孢噻肟、多黏菌素B和多西环素较为敏感,对SPF鸡致病性较弱,可引起一过性精神沉郁和泡沫粪,对樱桃谷鸭有较强的致病性,可引起死亡和严重的纤维素性心包炎、肝周炎和气囊炎。研究表明分离的肉种鸡源RA对鸡致病力相对较弱,结果为临床鸡群感染RA的诊断与防控提供参考。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Identification of Rickettsia felis in fleas but not ticks on stray cats and dogs and the evidence of Rickettsia rhipicephali only in adult stage of Rhipicephalus sanguineus and Rhipicephalus haemaphysaloides

Rickettsia spp. are zoonotic pathogens and mainly transmitted by various arthropod vectors, such as fleas, ticks, and lice. Previous epidemiological studies indicated that ectoparasites infested on dogs or cats may be infected by Rickettsia spp., and transmit them to human beings accidentally. In this study, the prevalence of Rickettsia infection was evaluated using fleas and ticks from stray dogs and cats in Taiwan. A total of 158 pools made by 451 cat fleas (Ctenocephalides felis) from 37 dogs and 4 cats were used for analysis. Besides, 386 Rhipicephalus ticks collected from the other 62 stray dogs were included in this study. Nymphal and adult ticks were individually analyzed but larvae were separated into 21 pools for molecular detection. Partial sequencing analysis of the gltA gene was applied for Rickettsia identification. The results showed that 44.3% (70/158) of the cat flea pools were harboring Rickettsia DNA. Although 6.9% (13/187) of adult ticks were infected with Rickettsia, neither larval pools nor nymphal ticks were found to contain Rickettsia DNA. According to the results of sequencing analyses, all Rickettsia PCR-positive cat flea pools were infected with R. felis, and all Rickettsia PCR-positive adult ticks were infected with R. rhipicephali. The results of this study demonstrated that C. felis but not Rhipicephlus sanguineus (the brown dog tick) and Rh. haemaphysaloides collected from stray animals in Taiwan could be infected the zoonotic pathogen R. felis. Moreover, R. rhipicephali was only identified in adult stage of Rhipicephalus sanguineus and Rh. haemaphysaloides.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Prevalence and seasonal incidence of larval and adult cestode infections of sheep and goats in eastern Ethiopia

A study on the prevalence and seasonal incidence of cestode parasite infections of sheep and goats was carried out in eastern Ethiopia for 2 years (May 2003-April 2005). During this period, viscera including liver, lungs, heart, kidneys and the gastro-intestinal tract were collected from 655 sheep and 632 goats slaughtered at four abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga. At the abattoirs the abdominal, thoracic and pelvic cavities as well as the muscle surfaces of all animals were visually examined for the presence of larval (cystic) stages of cestode parasites. The viscera were transported within 24 h to the parasitology laboratory of Haramaya University and were examined for larval and adult cestodes following standard procedures. The most prevalent metacestodes (larval cestodes) were Cysticercus ovis (Taenia ovis), Cysticercus tenuicollis (T. hydatigena) and hydatid cysts (Echinococcus granulosus). In sheep, the overall prevalence was 26% for C. ovis, 79% for C. tenuicollis, and 68% for hydatid cysts. Similarly, for goats, the corresponding prevalence was 22%, 53% and 65%, respectively. The difference between sheep and goats in prevalence of C. tenuicollis was significant. The high prevalence of hydatid cysts in both sheep and goats indicates that cystic echinococcosis/hydatidosis is a public health problem in these regions which requires implementation of control measures, including public health education, strict meat inspection and control of stray dogs. The results of the survey also implies that infections of small ruminants with these metacestodes are responsible for condemnation of substantial quantities of affected organs and muscles and therefore of direct economic importance. Intestinal infections with adult tapeworms of Moniezia expansa, Avitellina centripunctata and Stilesia globipunctata, and bile duct infections with Stilesia hepatica were also common in both sheep and goats. In sheep, the overall prevalence of these tapeworms were 61%, 20%, 24% and 39%, respectively. Similarly, the overall prevalence of these parasites in goats was 53%, 21%, 27% and 36%, respectively.     

Prevalence and genetic characterization of Giardia and Cryptosporidium in cats from Italy

One hundred and eighty one cats living in central Italy were tested for the presence of Giardia and Cryptosporidium infection by IFAT test and specific PCRs. Overall eight (4.4%) samples were IFAT-positive for Giardia. All the IFAT-positive samples for Giardia scored positive for the PCRs, and three more samples IFAT-negative generated PCR products leading to a total 6.1% molecular positivity rate for Giardia. All the examined samples were negative for Cryptosporidium. Sequencing of samples molecularly positive to Giardia indicated that three cats harbored the zoonotic Giardia duodenalis Assemblage A, whereas all other positive animals were infected with the feline-specific G. duodenalis Assemblage F. Phylogenetic analysis carried out on the sequences obtained supported the clustering of the isolates within Assemblages A and F. The results here presented provide data on the occurrence of Giardia genotypes in cats living in close contact with humans highlighting the potential importance of this protozoan disease for the public health.     

PCR-based detection of blood parasites in cattle and adult Rhipicephalus appendiculatus ticks

To ascertain the infection rate for tick-borne pathogens in Zambia, an epidemiological survey of Theileria parva, Babesia bigemina and Anaplasma marginale in traditionally managed Sanga cattle was conducted using PCR. Of the 71 native Zambian cattle, 28 (39.4%) were positive for T. parva, 16 (22.5%) for B. bigemina and 34 (47.9%) for A. marginale. The mixed infection rate in cattle was 8.5% (6/71), 16.9% (12/71), 7.0% (5/71) and 2.8% (2/71) for T. parva/B. bigemina, T. parva/A. marginale, B. bigemina/A. marginale and T. parva/B. bigemina/A. marginale, respectively.To predict the risk for transmission of tick-borne pathogens from ticks to cattle, a total of 74 Rhipicephalus appendiculatus ticks were collected from a location where cattle had been found positive for T. parva. Of the ticks collected, 10 (13.5%) were found to be PCR-positive for T. parva. The results suggest that the infection rate for tick-borne pathogens was relatively high in Sanga cattle and that adult R. appendiculatus ticks were highly infected with T. parva.     

The distribution of invA,pagC and spvC genes amongSalmonella isolates from animals

New molecular diagnostic techniques often rely on hybridization or amplification of specific DNA regions to detect pathogenic bacteria. The choice of genes to be used as probes or as the targets of amplification techniques is critical to the success of these procedures. The genes so used might best be those associated with virulent isolates and having a wide distribution among such isolates. In this study three genes,invA, pagC andspvC, thought to be associated with the virulence of salmonellae, were labelled and used to probe the total DNA from 103Salmonella isolates from animals in an attempt to determine whether these genes might be useful in diagnostic procedures.pagC was detected in 99% of theSalmonella tested, andinvA was detected in 94.2% of the isolates. BothpagC andinvA were detected with a significantly higher frequency thanspvC in isolates from chickens and swine, but no significant difference in detection of these three genes occurred when bovine isolates were examined. Failure to detect any of these genes occurred in only one isolate. Isolates from apparently healthy or from clinically ill chickens and swine could not be distinguished by detecting these three genes. The genes were not detected in the non-Salmonella strains tested. These results suggest that, of these three genes,pagC may be the best choice for use as a probe or polymerase chain reaction target in future detection protocols.Abbreviations df degrees of freedom - H apparently healthy animal - I animal diagnosed clinically as having salmonellosis - LB Luria-Bertani - NDSU North Dakota State University in Fargo, North Dakota - NS not significantly different - NVSL National Veterinary Services Laboratory in Ames, Iowa - PCR polymerase chain reaction - SDS sodium dodecylsulphate - UGA University of Georgia in Athens, Georgia     

Phylogentic analysis of Anaplasma ovis strains isolated from sheep and goats using groEL and mps4 genes

Evidence of Anaplasma spp. in goats and sheep in Cyprus has been demonstrated by previous research. Herein, further research was performed for the identification of the exact Anaplasma spp. resulting in the identification of Anaplasma ovis strains in all samples examined. We used a bioinformatics as well as a molecular approach (study of groEl and mps4 genes) in order to verify the validity of the results. All samples depicted the presence of A. ovis regardless of the host (goat or sheep).     

Green tea flavan-3-ols and oligomeric proanthocyanidins inhibit the motility of infective larvae of Teladorsagia circumcincta and Trichostrongylus colubriformis in vitro

The effects of a hot water infusion and an aqueous acetone extract of green tea (Camellia sinensis) on the motility of infective larvae of the sheep nematodes Teladorsagia circumcincta and Trichostrongylus colubriformis were investigated under in vitro conditions. The infusion and extract dose-dependently inactivated the infective larvae as assessed by the larval migration inhibition (LMI) assay. To determine the components responsible for the inhibitory activity, the hot water infusion and aqueous acetone extract of green tea were fractionated on Sephadex LH-20 and the green tea extract fractions (GTE-I-VIII) characterised by mass spectrometry. The larvae were exposed to increasing concentrations of these GTE fractions. Fractions containing epigallocatechin gallate (EGCG) and proanthocyanidin oligomers were most effective. GTE fractions were more effective against T. circumcincta than T. colubriformis larvae as assessed by the LMI assay.     

Detection and genotypic differentiation of Campylobacter jejuni and Campylobacter coli strains from laying hens by multiplex PCR and fla-typing

In total, 26 Campylobacter (C.) strains, isolated from liver, spleen, caecal or jejunal content of laying hens from different flocks were examined. In these flocks a drop in egg production, an increasing mortality and livers with whitish-grey lesions as post-mortem finding were observed. Suspected Campylobacter colonies were differentiated using a modified m-PCR in 13 Campylobacter jejuni and 13 Campylobacter coli strains. All isolates were characterised by typing of the flaA and flaB gene each with two restriction enzymes. To compare the four different profiles for all strains an artificial “fla-type” was generated. Different and identical fla-types of C. jejuni and C. coli were recovered from both intestinal and extra-intestinal organs of the laying hens and even from individual birds. One significant observation is that some fla-types of C. jejuni or C. coli were detected in intestinal and systemic sites but not all fla-types of both species appeared to be equally able to invade internal organs.