普鲁卡因青霉素-硫酸双氢链霉素混悬液在猪体内的药物动力学

健康长白猪7头,按拉丁方试验设计,进行单剂量静脉注射青霉素(20 000单位/kg体重)钠、硫酸双氢链霉素(20 000单位/kg体重)及肌肉注射普鲁卡因青霉素-硫酸双氢链霉素混悬剂(20 000单位/kg体重)的药物动力学研究。HPLC法和HPLC-MS/MS法分别测定血浆中的青霉素和双氢链霉素浓度,WinNonlin软件处理血药浓度-时间数据。静脉注射青霉素钠、硫酸双氢链霉素的药时数据最佳模型为三室开放模型。肌肉注射混悬剂后青霉素G的药时数据符合一级吸收一室模型。主要药物动力学参数:t1/2ka为0.66 h,t1/2β为5.80 h,t(max)为2.3 h,C(max)为1.66 mg/L,AUC为17.65,CL为0.69 L/h.kg,F为70.57%;肌肉注射混悬剂后双氢链霉素数据符合一级吸收二室开放模型,主要药动参数:t1/2ka为0.21 h;t1/2α为2.06 h;t1/2β为8.22 h,t(max)为0.8 h,C(max)为51.42 mg/L,AUC为280.74,F为101.96%。肌肉注射混悬液药物动力学特征为青霉素G吸收迅速,消除缓慢;双氢链霉素吸收迅速完全,消除缓慢,生物利用度高。     

二氟沙星对实验性感染猪链球菌病及支原体性肺炎的药效学研究

本文报道国内新近研制的畜禽专用氟喹诺酮类抗菌药物－二氟沙星对实验性感染猪链球菌病及支原体性肺炎的药效学研究。以试管两倍稀释法测得二氟沙星对兰氏C群类马链球菌（C55120）和猪肺炎支原体（F16株）的最小抑菌浓度（MIC）分别是1．6级及0．16mg/L。肌注给药对猪链球菌病和支原体性肺炎的实验性治疗结果表明，低、中、高剂量二氟沙星组（2．5、5、10mg/kg)及恩诺沙星组（2．5mg/kg)用药5d（每隔12h给药1次）对猪链球菌病的治愈分别是40％、70％、80％及70％，而链球菌感染对照组的死亡率为70％；低、中、高剂量二氟沙星组及恩诺沙星组（2．5mg/kg)用药5d（每隔12h给药1次）对猪支原体性肺炎的治愈率分别是80％、90％、90％及80％；而支原体感染对照组的自愈率为10％。     

头孢噻呋混悬剂对猪链球菌Ⅱ型小鼠模型的治疗试验

建立小鼠链球菌病的模型,评价头孢噻呋混悬剂的疗效。选用小白鼠人工感染猪链球菌Ⅱ型建立疾病模型,并应用不同剂量头孢噻呋混悬剂进行治疗试验。结果表明,链球菌Ⅱ型感染的小鼠模型能表现出典型的临床症状及病理变化,且具有较好的重复性。5和10mg/kg组治愈率均为100%,2mg/kg组治愈率为70%。因此,头孢噻呋混悬剂作为注射剂治疗小鼠猪链球菌Ⅱ型感染以剂量5mg/kg为佳。     

沙拉沙星对实验性感染猪链球菌病及大肠杆菌病的药效学

为兽医临床合理应用沙拉星（Ｓarafloxacin）提供理论依据,就其对实验性感染猪链球菌 病及大肠杆菌病的药效学进行了研究。以试管２倍稀释法测得沙拉沙星对兰氏Ｃ群类马链球菌（Ｃ５５１２０）和猪大肠杆菌（Ｏ５５）的最小抑菌浓度（ＭＩＣ）分别是０．８mg/Ｌ及０．０５mg/Ｌ。肌注给药对猪链球菌病和大肠杆菌病的试验性治疗结果不明,低、中 高剂量沙拉沙星组２．５、５、１０mg/kg）及环丙沙星组（５mg/kg）用药５d（每隔１２     

头孢噻呋混悬剂治疗人工感染仔猪传染性胸膜肺炎的效果观察

将头孢噻呋混悬剂分为高、中、低(10、5、2.5 mg/kg体重)3个剂量组分别肌肉注射治疗仔猪传染性胸膜肺炎,每36 h用药1次,连用2次;同时设头孢噻呋钠注射液对照组,按10 mg/kg体重给药,2次/d,连用3 d。结果表明,头孢噻呋混悬剂3个剂量组和头孢噻呋钠注射液对照组对仔猪传染性胸膜肺炎均有明显的治疗效果,成活率可达80％～100％,极显著高于感染对照组(P<0.01)。头孢噻呋混悬剂中、高剂量组成活率极显著高于头孢噻呋混悬剂低剂量组及头孢噻呋钠注射液组 (P<0.01)。本试验结果表明,头孢噻呋混悬剂能减少胸膜肺炎放线杆菌人工感染引起的临床症状,降低死亡率。作为注射剂治疗仔猪传染性胸膜肺炎,以5～10 mg/kg体重的剂量为佳。      

头孢噻呋混悬剂对放线杆菌小鼠病理模型的治疗试验

为评价头孢噻呋混悬剂对猪胸膜肺炎放线杆菌病的疗效,本试验通过小鼠人工感染猪胸膜肺炎放线杆菌建模,用不同剂量的头孢噻呋混悬剂(2、5、10mg/kg)进行临床疗效试验,并用头孢噻呋钠注射剂作为对照,结果5mg/kg和10mg/kg组治愈率均为100%,且头孢噻呋混悬剂较头孢噻呋注射剂效果更佳。因此,头孢噻呋混悬剂以5mg/kg剂量治疗小鼠放线杆菌病效果显著。     

氟甲喹可溶性粉对实验性鸡大肠杆菌病的药效学研究

以试管肉汤两倍稀释法测得氟甲喹、恩诺沙星、强力霉素对鸡大肠杆菌的MIC分别为0.5、0.025及32mg/l,按2.5、5和10mg/kg的氟甲喹及5mg/kg的恩诺沙星分别给实验性鸡大肠杆菌病患鸡给药,每12小时给药1次,共3天。氟甲喹低、中、高剂量组及恩诺沙星组对鸡大肠杆菌病的治愈率分别为76.7%、83.3%、86.7%及93.3%,而感染对照鸡的死亡率为43.3%。氟甲喹中、高剂量组及恩诺沙星组的增重效果极显著高于感染对照鸡(P<0.01)。     

抗菌肽NZ2114对多重耐药2型猪链球菌感染小鼠的治疗效果评价

为探究抗菌肽NZ2114对猪链球菌感染小鼠模型的体内治疗效果,本试验以NZ2114和2型猪链球菌CVCC 3928为研究对象,利用小鼠模型评价NZ2114治疗猪链球菌感染的效果。36只ICR雌鼠随机均分为6组:空白对照组(不感染,腹腔注射0.2mL PBS)、阴性对照组(感染,腹腔注射0.2mL PBS)、试验Ⅰ和Ⅱ组(感染,分别腹腔注射0.2mL 2.5和5.0mg/kg NZ2114)、阳性对照Ⅰ和Ⅱ组(感染,分别腹腔注射0.2mL 7.5和15.0mg/kg头孢曲松钠)。结果显示,空白对照组和5.0mg/kg NZ2114试验组小鼠存活率均为100%,而15.0mg/kg头孢曲松钠阳性对照组小鼠存活率仅为50%。治疗1d后,5.0mg/kg NZ2114试验组小鼠肺脏和肝脏荷菌量分别下降59.41%(P0.01)和69.19%(P0.01);而15.0mg/kg头孢曲松钠阳性对照组中小鼠肺脏和肝脏荷菌量分别下降43.94%(P0.01)和19.60%(P0.05)。与阴性对照组相比,2.5 mg/kg NZ2114治疗组中抑制炎性因子TNF-α和IL-1β的释放分别下降85.83%(P0.01)和56.20%(P0.05),5.0 mg/kgNZ2114试验组分别降低84.02%(P0.01)和43.86%(P0.05),而15.0mg/kg头孢曲松钠阳性对照组TNF-α及IL-1β的下降率均不显著,分别为24.49%和8.82%。另外,5.0mg/kg NZ2114试验组1d后即可明显减轻小鼠肺组织间质弥漫性炎细胞浸润等炎症症状,抑制肝细胞产生肿胀及空泡性变化,促进脾小结恢复正常;治疗7d后各器官组织临床症状评分基本恢复正常。上述结果表明,NZ2114能有效提高猪链球菌感染小鼠的存活率,显著降低病原菌在小鼠肺脏和肝脏的移位及血清中TNF-α和IL-1β的水平,并有效缓解肝脏、脾脏和肺脏的急性损伤,治疗效果优于头孢曲松钠,具有作为治疗临床猪链球菌病抗生素替代品的潜力。     

三氯苯咪唑混悬剂对牦牛肝片吸虫的驱虫试验

应用三氯苯咪唑混悬剂,选择自然感染肝片吸虫的牦牛60头进行了驱虫试验。结果表明:①三氯苯咪唑混悬剂5mg/kg体重剂量对肝片吸虫的虫卵转阴率、减少率分别为83.3%、90.0%,对成虫的驱净率和驱虫率分别为91.7%、93.8%,对童虫的驱净率和驱虫率分别为83.3%、90.1%;10、15mg/kg剂量对肝片吸虫虫卵转阴率、减少率及成虫、童虫的驱净率和驱虫率均达100%;②三氯苯咪唑混悬剂10mg/kg剂量与同剂量三氯苯咪唑片剂的驱虫效果无明显差异;③三氯苯咪唑混悬剂3个剂量组试验牛未见异常反应。试验证明三氯苯咪唑混悬剂10、15mg/kg剂量驱除牦牛肝片吸虫高效安全,临床使用以10mg/kg剂量为宜。     

头孢噻呋混悬剂治疗人工复制仔猪黄白痢的效果观察

将头孢噻呋混悬剂以高、中、低(10、52、.5 mg/kg)3个剂量组,分别肌肉注射治疗仔猪黄白痢,每24 h用药1次,连用3次,同时设对照组。结果表明,头孢噻呋混悬剂3个剂量组和头孢噻呋钠注射液对照组对仔猪黄白痢均有明显的治疗效果,成活率可达80%~100%,极显著的高于感染对照组(P<0.01)。头孢噻呋混悬剂中、高剂量组成活率显著高于头孢噻呋混悬剂低剂量组及头孢噻呋钠注射液组(P<0.01)。表明头孢噻呋混悬剂能减少大肠埃希菌人工感染引起的临床症状,降低病死率。作为注射剂治疗仔猪黄白痢,剂量以5 mg/kg~10 mg/kg为佳。     

Molecular survey of Dirofilaria immitis and Dirofilaria repens by direct PCR for wild caught mosquitoes in the Republic of Korea

Adult mosquito collections using New Jersey light traps and Black-hole light traps were conducted to determine the potential vectors and the relative mosquito infection rates of Dirofilaria immitis and Dirofilaria repens in Gyeonggi and Gangwon Provinces, Republic of Korea, 2005. Dirofilaria spp. were confirmed by polymerase chain reaction (PCR) using species-specific primers for D. immitis and D. repens. Minimum field infection rates (MFIR) [MFIR = (number infected pools/total number of mosquitoes) x 1000] of 12 pools/2059 total number mosquitoes (5.8) and 21 pools (10.1) of the wild caught mosquitoes were positive by PCR for D. immitis and D. repens, respectively. Dual infections of both D. immitis and D. repens were detected by PCR in eight pools (3.9). Anopheles sinensis sensu lato (includes An. sinensis s.s., An. pullus, An. kleini, An. belenrae, and An. lesteri), An. sineroides, Aedes vexans nipponi, Culex pipiens and Armigeres subalbatus were found to be infected and are potential vectors of D. immitis and D. repens in Korea. Infections observed in mosquitoes represent potential health risks for domestic animal and human populations.     

Gastrointestinal parasites of cavy (Cavia aperea aperea) in southern Brazil

The aim of this study was to evaluate the gastrointestinal parasitism in Cavia aperea aperea (cavy), captured in the central region of Rio Grande do Sul State. Fecal samples from five free-living cavies were collected for research of parasites. Samples were analyzed by the centrifugal-flotation method with zinc sulfate and parasites were identified microscopically based on (oo)cyst and egg size and morphology. Cysts of Giardia sp. and (oo)cysts of Cryptosporidium sp. and Cystoisospora sp. were observed in one or more cavies. Eggs of Paraspidodera uncinata were observed in three of the five rodents. All infected animals showed mild infection by parasite. This is the first report of Giardia sp., Cryptosporidium sp. and Cystoisospora sp. in Cavia a. aperea.     

Perspectives on canine and feline hepatozoonosis

Two species of Hepatozoon are currently known to infect dogs and cause distinct diseases. Hepatozoon canis prevalent in Africa, Asia, southern Europe, South America and recently shown to be present also in the USA causes infection mainly of hemolymphoid organs, whereas Hepatozoon americanum prevalent in the southeastern USA causes myositis and severe lameness. H. americanum is transmitted by ingestion of the Gulf Coast tick Amblyomma maculatum and also by predation on infected prey. H. canis is transmitted by Rhipicephalus sanguineus, in South America also by Amblyomma ovale, and has also been shown to be transmitted transplacentally. Hepatozoonosis of domestic cats has been described mostly from the same areas where canine infection is present and the exact identity of the species which infect cats, their pathogenicity and vectors have not been elucidated. The diagnosis of hepatozoonosis is made by observation of gamonts in blood smears, histopathology, PCR or serology. The main treatment for H. canis is with imidocarb dipropionate whereas H. americanum infection is treated with an initial combination of trimethoprim-sulfadiazine, pyrimethamine and clindamycin followed by maintenance with decoquinate. Treatment for both diseases has not been reported to facilitate complete parasite elimination and new effective drugs are needed for the management of these infections. Prevention of hepatozoonosis should be based on avoidance of oral ingestion of infected tick vectors and infected prey.     

Prevalence of Anaplasma,Bartonella and Borrelia Species in Haemaphysalis longicornis collected from goats in North Korea

North Korea is located on the northern part of the Korean Peninsula in East Asia. While tick-borne pathogens of medical and veterinary importance have been reported from China and South Korea, they have not been reported from North Korea. To screen for zoonotic tick-borne pathogens in North Korea, ticks were collected from domestic goats. A total of 292 (27 nymph, 26 male, 239 female) Haemaphysalis (H.) longicornis were collected and assayed individually for selected tick-borne pathogens. A total of 77 (26.4%) were positive for Anaplasma bovis, followed by Bartonella (B.) grahamii (15, 5.1%), Anaplasma phagocytophilum (12, 4.1%), Bartonella henselae (10, 3.4%), and Borrelia spp. (3, 1.0%) based on 16S ribosomal RNA and ITS species-specific nested polymerase chain reaction. Using the groEL-based nested PCR, a total of 6 and 1 H. longicornis were positive for B. grahamii and B. henselae, respectively. All products were sequenced and demonstrated 100% identity and homology with previously reported sequences from other countries in GenBank. This is the first report of the detection of tick-borne pathogens in the North Korea and suggests that farm animals may act as reservoirs for zoonotic tick-borne pathogens.     

Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health.     

Screening of microfilaricidal effects of plant extracts against Dirofilaria immitis

Canine dirofilariasis is a common tropical parasitic disease of companion animals, caused by infestation of Dirofilaria immitis filarids within the pulmonary arteries and extending into the right heart. Increased reports of adverse reactions elicited by current microfilaricidal agents against D. immitis such as neurological disorders, circulatory collapse and potential resistance against these agents, warrant the search for new agents in forms of plant extracts. The use of plant extracts in therapeutic medicine is commonly met with scepticism by the veterinary community, thus the lack of focus on its medical potential. This study evaluated the presence of microfilaricidal activities of the aqueous extracts of Zingiber officinale, Andrographis paniculata and Tinospora crispa Miers on D. immitisin vitro at different concentrations; 10 mg/ml, 1 mg/ml, 100 μg/ml, 10 μg/ml and 1 μg/ml within 24 h, by evaluation of relative microfilarial motility as a measure of microfilaricidal activity. All extracts showed microfilaricidal activity with Z. officinale exhibiting the strongest activity overall, followed by A. paniculata and T. crispa Miers. It is speculated that the microfilaricidal mechanism exhibited by these extracts is via spastic paralysis based upon direct observation of the microfilarial motility.     

Dissimilarity of ccrAB gene sequences between methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus among bovine isolates in Korea

The sequences of the ccrAB genes from bovine-, canine- and chicken-originating methicillin-resistant Staphylococcus (S.) epidermidis (MRSE) and bovine methicillin-resistant Staphylococcus (S.) aureus (MRSA) were compared to investigate the frequency of intra-species horizontal transfer of the staphylococcal cassette chromosome mec (SCCmec) complex. Nineteen MRSE strains were isolated from bovine milk, chickens, and dogs, and their genetic characteristics were investigated by multilocus sequence typing and SCCmec typing. Among the animal MRSE strains, the most frequent SCCmec type was type IV, which consisted of the type B mec complex and ccrAB type 2. The ccrA2 and ccrB2 genes were sequenced from the bovine, chicken and canine MRSE strains and compared with those of the bovine MRSA strains. The sequences generally clustered as MRSA and MRSE groups, regardless of the animal source. Additionally, no bovine MRSE sequence was associated with the bovine MRSA groups. Although most of the bovine MRSE and MRSA isolates possessed SCCmec type IV sequences, our results suggest that the intra-species gene transfer of the SCCmec complex between bovine S. aureus and bovine S. epidermidis strains is not a frequent event.     

Molecular detection of zoonotic tick-borne pathogens from ticks collected from ruminants in four South African provinces

Ticks carry and transmit a remarkable array of pathogens including bacteria, protozoa and viruses, which may be of veterinary and/or of medical significance. With little to no information regarding the presence of tick-borne zoonotic pathogens or their known vectors in southern Africa, the aim of our study was to screen for Anaplasma phagocytophilum, Borrelia burgdorferi, Coxiella burnetii, Rickettsia species and Ehrlichia ruminantium in ticks collected and identified from ruminants in the Eastern Cape, Free State, KwaZulu-Natal and Mpumalanga Provinces of South Africa. The most abundant tick species identified in this study were Rhipicephalus evertsi evertsi (40%), Rhipicephalus species (35%), Amblyomma hebraeum (10%) and Rhipicephalus decoloratus (14%). A total of 1634 ticks were collected. DNA was extracted, and samples were subjected to PCR amplification and sequencing. The overall infection rates of ticks with the target pathogens in the four Provinces were as follows: A. phagocytophilum, 7%; C. burnetii, 7%; E. ruminantium, 28%; and Rickettsia spp., 27%. The presence of B. burgdorferi could not be confirmed. The findings of this study show that zoonotic pathogens are present in ticks in the studied South African provinces. This information will aid in the epidemiology of tick-borne zoonotic diseases in the country as well as in raising awareness about such diseases in the veterinary, medical and tourism sectors, as they may be the most affected.     

Climate and the epidemiology of gastrointestinal nematode infections of sheep in Europe

The free-living stages of gastrointestinal nematode parasites of sheep are strongly affected by climate. Thus, extreme heat and cold are detrimental to development and survival, while, within tolerable limits, increasing temperatures generally accelerate development but increase mortality. Moisture is needed for development and translation of larvae from faeces to pasture, and so rainfall is a limiting factor for transmission. Together, these factors underpin seasonal patterns of infection in sheep, as well as geographic variation in the epidemiology and relative importance of different species within Europe. Local knowledge and experience enable treatment to be targeted appropriately to prevent dangerous levels of infection. This traditional know-how can be supplemented by predictive epidemiological models, built on thorough understanding of the influence of climate on larval availability. However, management also has a dominant role in determining patterns of infection, and is itself influenced by climate. Current geographic variation in nematode epidemiology across Europe, and knowledge of systems from outside Europe, can provide only limited perspectives on the likely effects of climate change on disease in future. This is because disease arises from complex interaction between host and parasite factors, and the implementation of optimal control strategies to meet new challenges will be slowed by the inertia of current systems. Approaches to nematode control must therefore take account not only of parasite biology, but also the forces that shape sheep farming systems and management decisions.     

A Multiplex Polymerase Chain Reaction Assay for Direct Detection and Differentiation of β-Hemolytic Streptococci in Clinical Samples from Horses

Streptococcus equi subspecies equi, S equi subspecies zooepidemicus, and S dysgalactiae subspecies equisimilis are β-hemolytic Streptococci, often isolated from horses with respiratory or genital diseases. The aim of this study was (i) defining and validating a multiplex polymerase chain reaction (PCR) protocol for identifying these Streptococci in bacterial cultures and for detecting them directly in equine clinical specimens, and (ii) defining and validating a cheap DNA extraction protocol for clinical specimens. When respiratory and genital samples from symptomatic and asymptomatic horses were tested by bacterial culture and by multiplex PCR, all the 150 samples culture-positive for S equi, S zooepidemicus, or S equisimilis were also positive by PCR. Of 150 culture-negative samples, 143 were negative by PCR. Seven samples were positive by PCR but negative by bacteriology. The multiplex PCR protocol described in this study is proven suitable for a sensitive, specific, and rapid detection and identification of S equi, S zooepidemicus, and S equisimilis in cultured bacterial colonies, as well as in clinical specimens from symptomatic or asymptomatic horses. The inclusion of internal control primers in the PCR protocol excludes false-negative results. A cheap DNA extraction method has been also validated for swabs, tracheal aspirates, bronchoalveolar lavage, and guttural pouches lavage samples.