A longitudinal study of serological patterns of respiratory infections in nine infected Danish swine herds

Sixteen litters of seven pigs from each of nine Danish farrow-to-finish herds were followed to investigate the serological patterns caused by natural infection with Mycoplasma hyopneumoniae, Pasteurella multocida toxin and Actinobacillus pleuropneumoniae serotypes 2, 5–7, 12. In seven of the herds, pigs were followed as two separate cohorts started 4 weeks apart, and in two herds only one cohort was followed.

A total of 999 pigs were included in the study. The pigs were blood sampled at weaning and subsequently every fourth week until slaughter. All pigs were examined for antibodies against M. hyopneumoniae (enzyme-linked immunosorbent assay), P. multocida toxin (enzyme-linked immunosorbent assay) and A. pleuropneumoniae serotypes 2, 5–7, 12 (complement-fixation tests). The most-common pattern (28%) of seroconversion was that of pigs first seroconverting to A. pleuropneumoniae serotype 2, followed by seroconversion to M. hyopneumoniae. Each herd had a dominant serotype of A. pleuropneumoniae to which most pigs seroconverted. Seroconversion to the respiratory pathogens occurred mainly in the growing-to-finishing units (8–24 weeks). The risk of seroconversion to the P. multocida toxin was very low (<20%) and occurred late.

None, four and seven herds tested seropositive to PRRS and to swine influenza virus subtypes H3N2 and H1N1, respectively, when testing 10 pigs per herd (selected randomly among the study pigs) at the age of 20 weeks.     

Serological survey to determine the occurrence of respiratory Mycoplasma infections in the Polish cattle population

Mycoplasma bovis and Mycoplasma mycoides subspecies mycoides small colony (MmmSC) are causes of bovine mycoplasmosis and contagious bovine pleuropneumonia (CBPP), respectively, and are responsible for serious economic losses in cattle around the world. CBPP was last reported in Poland in 1939 but bovine mycoplasmosis is believed to be endemic. A survey of 3670 serum samples for antibodies to M bovis and MmmSC from 361 herds in 16 Polish provinces Poland between 2007 and 2010 found no evidence of CBPP. The seroprevalence of M bovis, however, appeared high with 76.7 per cent of samples giving a positive reaction in the ELISA test, which did not appear to reflect the clinical disease status of the cattle. Adjusting the sensitivity of the test reduced the prevalence to 28.2 per cent and reflects the levels reported in other European countries.     

应重视家禽多病因呼吸道病的防制

阐明家禽多病因呼吸道病各种病原和环境因素间相互关系。这种呼吸道病是多种病因引起并发和混合感染 ,比单一感染更多见。根据家禽多病因呼吸道病的特点 ,提出多病因呼吸道病的综合防制对策 ,以达到控制这种病的目的     

A serological survey to determine the prevalence of infection with Treponema hyodysenteriae in Western Australia

A serological survey to detect antibody titres against Treponema hyodysenteriae was conducted on pigs from 106 herds in Western Australia. Titres indicating a positive result in the tests were determined by examining 400 sera from 4 herds known to be free of swine dysentery, and sera from immunised or experimentally infected pigs. Samples of serum from 40 bacon-weight pigs from each of the 106 herds were then collected at 2 abattoirs. Each serum was tested in enzyme-linked immunosorbent assays (ELISA) against the lipopolysaccharide of T hyodysenteriae of serogroups A, B and E, respectively. To assist in evaluating the test, 19 herds were resampled and retested, and faecal samples from 17 herds were cultured for T hyodysenteriae. Thirty-five of the 106 herds (33%) had serological evidence of infection when only one batch of sera from each herd was tested. The ELISA to detect T hyodysenteriae infection in herds using 40 sera was estimated as having a sensitivity of 77.3% and a specificity of 81.8% based on the owners' opinion of their herds disease status. Prevalence of infection within herds ranged from 2.5% to 47.5%, with a mean of 18%.     

控制鸡的支原体感染

由于支原体感染事件在世界各地的鸡群中接连发生,因而有必要对该病加以控制。对蛋种鸡、后备母鸡和肉鸡施予适当的控制方法后,就能够成功地减少因支原体感染造成的经济损失。     

甘肃省猪衣原体病的血清学调查

1998～2000年，对全省未进行过猪衣原体病免疫的11个地州市的868份猪血清应用间接血凝(IHA)试验进行抗体检测。结果在11个地市中均检出抗体阳性猪血清，全省猪衣原体病的阳性检出率平均为34．91％，阳性检出率最高达52．48％，最低13．95％。     

几种常见禽呼吸道疾病的诊断

新城疫、禽流感、传染性支气管炎、传染性喉气管炎、传染性鼻炎、慢性呼吸道病和曲霉菌病是几种常见的禽类传染病,这几种疾病均有不同程度的呼吸道症状而引起呼吸功能障碍。不仅为临床诊断带来一定困难,而且造成了很多养禽专业户的巨大经济损失。笔者参考大量相关资料,归纳出这几种疾病的临床症状和病理解剖变化以及特征性差异。 1 新城疫 新城疫又称亚洲鸡瘟,是由病毒引起的一种高度接触性传染病,鸡和火鸡最易感染,雏鸡易感性和死亡率比老龄鸡高,且多呈急性型。主要特征是呼吸困难,下痢,神经机能紊乱,粘膜和浆膜出血。本病一年四季均可发生,但以冬春较易流行,典型性新城疫发病率和死亡率可高达90%以上。 1.1 主要临诊症状 典型性新城疫:发病突然,常无特征性症状而迅速死亡。常见症状是张口呼吸,甩头,伸颈,精神沉郁,食欲减退或消失,渴欲增加。病鸡不愿走动,垂头,翅膀下垂,好睡,体温上升可达43～44℃。嗉囊积液,倒提病鸡时从口中流出酸臭味流体。排出黄白色或黄绿色稀粪,有时混有血液。有的病鸡可出现两腿麻痹、站立不稳、歪颈、肌肉震颤等神经症状。非典型新城疫:主要表现呼吸道症状和神经系统障碍。发病率和死亡率低。成鸡轻者表现食欲减少,产蛋率下降10%～30%,2～3个月可恢复正常。重者精神沉郁、嗜睡、呼吸困难、下黄色或黄褐色稀粪。中雏、幼雏表现为呼吸困难、伸颈张口,病程稍长者出现头颈扭曲、转圈等神经症状。 1.2 病理解剖 剖检可见腺胃粘膜水肿出血,粘膜乳头或粘膜上皮有分散的出血点,腺胃和肌胃交界处更为明显。小肠前段出血,盲肠扁桃体肿大、出血和坏死。气管出血或坏死,周围组织水肿,肺有时可见淤血和水肿。 2 禽流感     

Immune mechanisms in infections of poultry

Resistance to infectious agents may depend upon innate mechanisms or acquired immune responses. Inflammation, phagocytosis, cell-mediated immunity and antibodies are components of a complex reaction which result either in resistance or in susceptibility. Most infectious organisms stimulate immune responses within every compartment of the immune system. In rather few infections of poultry, it is possible to pinpoint a limited number of immune reactions that are primarily responsible for resistance. In some situations, autoimmunity may contribute to the pathology associated with infections.     

A urease-ELISA for the detection of mycoplasma infections in poultry

An ELISA utilising a urease-antibody conjugate specific to chicken IgG was examined as an alternative to the serum agglutination and the haemagglutination inhibition tests in the diagnosis of Mycoplasma gallisepticum and M. synoviae infections in poultry. Use of a urease conjugate allowed the serum reactions to be appraised without the need for expensive photometric equipment. Non-specific binding of conjugate to antigen was eliminated by treatment of antigen coated microplates with 10% foetal calf serum in phosphate buffered saline. Some chicken serums produced non-specific reactions. These reactions were reduced without any loss of test sensitivity by making the initial 1:5 dilution of chicken serum in whole sheep serum rather than diluting buffer. Tests on serums from experimentally infected chickens showed that the urease ELISA was specific, and was as sensitive as the serum agglutination test but more sensitive than the haemagglutination inhibition test.     

A serological survey of canine respiratory coronavirus in New Zealand

ABSTRACT

Aims: To determine the seroprevalence of canine respiratory coronavirus (CRCoV) in New Zealand dogs, and to explore associations with age, sex, breed, month, and geographical region of sampling and reported presence of clinical signs suggestive of respiratory disease.

Methods: A total of 1,015 canine serum samples were randomly selected from submissions to a diagnostic laboratory between March and December 2014, and were analysed for CRCoV antibodies using a competitive ELISA. Logistic regression analysis was used to determine associations between seroprevalence of CRCoV and breed category, age, sex, sampling month, region, and reported health status of dogs.

Results: Overall, 538/1,015 (53.0%) samples were seropositive for CRCoV, with 492/921 (53.4%) positive dogs in the North Island and 46/94 (49%) in the South Island. Age of dog, sampling month, region, and presence of abnormal respiratory signs were included in the initial logistic regression model. Seroprevalence was higher in dogs aged ≥3 compared with ≤2 years (p?<?0.01). The lowest seroprevalence was observed in July (30/105; 28.5%) and August (32/100; 32%), and the highest in June (74/100; 74%). Seroprevalence in dogs from Auckland was higher than in dogs from the Hawkes Bay, Manawatu, Marlborough, and Waikato regions (p?<?0.05). Abnormal respiratory signs (coughing, nasal discharge, or sneezing) were reported for 28/1,015 (2.8%) dogs sampled. Seroprevalence for CRCoV tended to be higher among dogs with respiratory signs (67.9 (95% CI?=?47.6–83.4)%) than dogs with no reported respiratory signs (52.6 (95% CI?=?49.5–55.7)%).

Conclusions: Serological evidence of infection with CRCoV was present in more than half of the dogs tested from throughout New Zealand. Differences in CRCoV seroprevalence between regions and lack of seasonal pattern indicate that factors other than external temperatures may be important in the epidemiology of CRCoV in New Zealand.

Clinical relevance: Our data suggest that CRCoV should be included in investigations of cases of infectious canine tracheobronchitis, particularly if these occur among dogs vaccinated with current vaccines, which do not include CRCoV antigens.     

钦州市禽流感免疫抗体水平监测及分析

钦州市2005年秋冬季高致病性禽流感免疫工作从10月底开始,总共调运禽流感灭活乳剂苗807.65万mL、禽流感鸡痘病毒载体重组苗1847.6万只份,对全市3217.94万只鸡、1088.9万只水禽进行突击免疫接种.     

Alphaherpesvirus infections in semidomesticated reindeer: A cross-sectional serological study

Alphaherpesviruses infect a wide range of animal species and cause diseases. Cervid herpesvirus 2 (CvHV-2) was originally isolated from reindeer in Finland but the impact of CvHV-2 infections on reindeer remains unclear. CvHV-2 infection could be partly responsible for calf losses as there are indications that it is associated with abortions and neonatal diseases. Previous serosurveys of reindeer (Rangifer tarandus tarandus) have shown that an alphaherpesvirus is circulating among reindeer in Norway. The aim of the present study was to determine the prevalence of CvHV-2 infection among reindeer in various herding districts in Finnmark, the largest reindeer area in Norway, and to identify factors associated with becoming infected with CvHV-2. A total of 3062 serum samples were tested using an ELISA and a sub-set of samples was further tested using a seroneutralization test. The ELISA revealed that 49% of samples were positive. Extrapolation of the results to the total population (111,350 animals; 66% of the Finnmark reindeer population) showed that the seroprevalence in the population was 48%. Seroprevalence varied from 7.6% to 90.7% between districts and was affected by age, weight and population density. ELISA-positive samples neutralized CvHV-2 at serum dilutions greater than those required for neutralization of bovine herpesvirus type 1. It is concluded that CvHV-2 is endemic throughout the reindeer herding districts of northern Norway.     

A serological investigation of Bartonella henselae infection in cats in Turkey

Bartonella henselae is the causative agent of cat scratch disease (CSD) in humans. Cats are the main reservoir of this bacterium and may infect humans through scratches and bites. The purpose of this study was to determine the B. henselae seroprevalence in cats in Turkey. A total of 298 cats blood samples were collected from six different provinces of Turkey. Sera were tested for the presence of anti-B. henselae IgG antibodies by indirect fluorescent antibody test (IFA). The seroprevalence of B. henselae was 27.9% (83/298) for the cats examined in this study. The seroprevalence of cats by province was significantly higher in Bursa (41.3%), Adana (33.9%), Aydin (27.5%) and Burdur (32.3%) than in Kayseri (17.9%) and Istanbul (12.5%). Statistically significant differences were not observed between cat sexes and living conditions of cats. The results revealed that B. henselae is an important zoonotic pathogen in Turkey.     

如何降低家禽沙门氏菌感染的风险(续完)

3预防沙门氏菌传播的措施3.1卫生和消毒在引进新一批鸡群前,所有鸡舍和器具必须进行清洁消毒,特别是在前一批鸡群为沙门氏菌阳性的情况下,清洁消毒就更有必要。卫生措施的有效性可通过严格的细菌学定量检测验证,要求肠道细