Ascaris suum: seasonal egg development rates in a Saskatchewan pig barn.

This study investigated the effects of seasonal temperature variations on the rate of development to infectivity of Ascaris suum eggs under western Canadian climatic conditions. Flasks containing a suspension of A. suum eggs were placed inside a pig barn located near Saskatoon, Saskatchewan, Canada, at monthly intervals from July 1997 to July 1998. Eggs from each flask were monitored weekly for development to the infective larval stage. Infectivity of eggs was confirmed using a mouse bioassay. Development to the infective stage took three to four weeks in summer when in-barn temperatures were similar to the external ambient temperature. Fall, winter and early spring egg development took longer as in-barn temperatures were cooler. Mid-winter egg development took as long as 11-12 weeks. The in-barn mean temperature during this period was approximately 17 C, close to the development threshold of A. suum eggs. These data are discussed in relation to similar studies from northern Europe and to potential control measures.     

Ascaris suum Infection in Calves III. Pathology

Gross changes in the lungs of Ascaris suum- infected calves consisted of atelectasis and hemorrhagic foci, edema and emphysema, frequently with bullae. Prominent microscopic lung lesions were edema and emphysema of the interlobular septa with large numbers of eosinophils within and around lymphatics, peribronchiolar lymphoid nodules and parasitic granulomas. Many of the microscopic features were consistent with those found in atypical interstitial pneumonia. Changes in the alveoli were atelectasis, the exudation of plasma proteins, mononuclear cells and eosinophils, and alveolar wall thickening. Lesions found later included fibrosis and fetalization of the alveolar walls. Plasma cells and neutrophils were not common. Challenge with Toxocara canis after sensitization with A. suum resulted in the lungs developing a few areas of atelectasis. Migration of T. canis to lungs of calves is slower than A. suum. A. suum larvae were always found in bronchi, bronchioles and alveoli of calves that died. Lesions were observed in the liver but not the kidney of A. suum infected calves; both lung and liver lesions tended to resolve with time.     

A Comparison of the Susceptibility of Growing Mukota and Large White Pigs to Infection with Ascaris suum

The influence of A. suum infection on the haematology, liver-related serum enzymes, blood urea and live weight gain in Mukota and Large White (LW) weaner pigs was compared. Six pigs of each genotype were infected with a single dose of 4000 A. suum eggs per pig and another six were not. The pigs were kept for 100 days. Blood was collected daily for the first 7 days and also after 100 days. In the infected pigs, there was an increase (p<0.05) in alanine aminotransferase (ALT) activity in the LW but not in the Mukota pigs. Although the alkaline phosphatase (ALP) activity rose (p<0.05) in both infected and non-infected LW pigs from day 1 to day 3, the activity in the non-infected LW pigs then decreased, while that of the infected LW pigs remained elevated. The infected LW pigs had higher (p<0.05) levels of ALT, ALP and aspartate aminotransferase than their non-infected counterparts. Non-infected LW pigs tended to have higher (p<0.05) haematological parameters, daily weight gain and urea concentrations than infected LW pigs, but these differences were not significant. These preliminary findings suggest that more A. suum larvae reached the livers in the LW than in the Mukota pigs and that the latter may be more resistant to A. suum infection.     

Ascaris suum Infection in Calves I. Clinical Signs

Clinical signs consistent with those of atypical interstitial pneumonia (AIP) were induced in calves sensitized with infective Ascaris suum eggs at seven to 20 weeks of age and challenged at three-week intervals one or more times. These signs usually appeared on the sixth or seventh day postinfection and reached maximum severity between the tenth and 13th days following infection. Prominent signs were: dyspnea, often with expiratory grunt, coughing, mouth breathing and emphysema as well as increased respiration and heart rates. In general, the intensity of signs was dependent upon dose size, although a single small dose resulted in acute signs and death in one calf. Intermittent coughing and vesicular sounds were induced in calves given A. suum eggs continually over prolonged periods. No respiratory abnormalities resulted from challenge with Toxocara canis after sensitization with A. suum. Antihistamine therapy did not alter the clinical signs in A. suum infected calves.     

Ascaris suum Infection in Calves II. Circulating and Marrow Eosinophil Responses

An increment in the number of circulating eosinophils occurred between the 11th and 14th days after infection with Ascaris suum and this increase was generally greater after a challenge infection. Continual infection with small numbers of A. suum eggs over prolonged periods resulted in circulating eosinophil levels which fluctuated and were dose-dependent. The per cent marrow eosinophils always increased after a primary infection and a greater increase usually followed a challenge infection. The maximum increment of marrow eosinophils occurred between the tenth and 12th days and preceded the rise in circulating eosinophils by 36 hours. Antihistamine therapy did not alter eosinophil responses to A. suum. Circulating eosinophilia was not usually reflected by drastic changes in differential white cell counts. However, an increase in total white cell count often followed infection with A. suum and frequently parallelled changes in eosinophil counts. Hemoglobin and P.C.V. values remained within normal limits in A. summ infected calves.     

An Abattoir Survey of the Incidence of Pneumonia in Saskatchewan Swine and an Investigation of the Microbiology of Affected Lungs

The lungs of 15 409 pigs, mostly from Saskatchewan, slaughtered at an abattoir were examined over a one year period. The incidence of lesions was 36.7% for “enzootic” pneumonia and 2.1% for pleurisy unassociated with pneumonia. Seasonal variations were recorded and compared with the results of similar surveys carried out in Australia, Belgium and England. Mycoplasmological examination of lungs from 347 animals was consistently negative for Mycoplasma hyopneumoniae. Pasteurella multocida was the commonest bacterial isolate, a result which agrees with those of other workers.     

Pneumonia in Saskatchewan Swine: Abattoir Incidence of Intrathoracic Lesions in Pigs from a Herd Infected with Haemophilus pleuropneumoniae and from Other Herds

A 1978-79 survey of the incidence of thoracic cavity lesions at slaughter had shown that the overall incidence of pleurisy in Saskatchewan swine was low (2%). Therefore, in the summer of 1979 a comparison was made between the incidence of pleurisy in a herd of pigs chronically affected with Haemophilus pleuropneumoniae pneumonia and in animals from other herds slaughtered at the same time. The incidence of pleurisy in control pigs (3.6%) was slightly higher than in the large scale survey but in the pigs from the Haemophilus infected herd it was almost four times as great (13.3%). In the same herd the survivors of a batch of pigs which had been decimated by more severe disease showed an incidence of 32% pleurisy. The economic implications of these findings are detailed and discussed.     

上新庄农区藏香猪蛔虫感染动态试验

藏香猪的蛔虫感染随着宿主年龄及环境季节的变化,其感染率和感染强度随之发生动态变化。藏香猪在2月龄时通过粪便开始排出虫卵,在5～7月龄时达到高峰,以后随着月龄的增长而感染降低,感染随季节性变化而出现动态变化。     

The development of Ascaris suum in calves.

To determine the development of Ascaris suum after a primary and a secondary infection, 18 calves were inoculated with 2,000,000 infective eggs and examined from 18 hours to 13 days postinfection. At 18 hours larvae were recovered from the wall of the abomasum, duodenum and jejunum. They were found in small intestine lymph nodes on the third day, in the liver at five days and were most abundant in the lungs on days 7 and 9. The pattern of recovery of larvae from the lung between days 5 and 13 postinfection was similar after a primary or a secondary infection. Slower growth of larvae following a secondary infection was the only evidence of resistance to A. suum. There were no pathological changes observed in the alimentary canal. White foci were found on the surface of the liver as early as the third day. The rapid decline in the number of A. suum in the lungs after the ninth day was considered to be related to immobilization or death of larvae soon after the reaction to them commences.     

Concurrent Ascaris suum and Oesophagostomum dentatum infections in pigs.

The aim of this study was to examine interactions between Ascaris suum and Oesophagostomum dentatum infections in pigs with regard to population dynamics of the worms such as recovery, location and length; and host reactions such as weight gain, pathological changes in the liver and immune response. Seventy-two helminth-na?ve pigs were allocated into four groups. Group A was inoculated twice weekly with 10000 O. dentatum larvae for 8 weeks and subsequently challenge-infected with 1000 A. suum eggs, while Group B was infected with only 1000 A. suum eggs; Group C was inoculated twice weekly with 500 A. suum eggs for 8 weeks and subsequently challenge-infected with 5000 O. dentatum larvae, whereas Group D was given only 5000 O. dentatum larvae. All trickle infections continued until slaughter. Twelve pigs from Group A and B were slaughtered 10 days post challenge infection (p.c.i.) and the remaining 12 pigs from the each of the four groups were slaughtered 28 days p.c.i.. No clinical signs of parasitism were observed. The total worm burdens and the distributions of the challenge infection species were not influenced by previous primary trickle-infections with the heterologous species. Until day 10 p.c.i. the ELISA response between A. suum antigen and sera from the O. dentatum trickle infected pigs (Group A) pigs were significantly higher compared to the uninfected Group B. This was correlated with a significantly higher number of white spots on the liver surface both on Day 10 and 28 p.c.i. in Group A compared to Group B. The mean length of the adult O. dentatum worms was significantly reduced in the A. suum trickle infected group compared to the control group. These results indicate low level of interaction between the two parasite species investigated.     

猪蛔虫GST蛋白编码基因克隆及序列分析

为预测并分析猪蛔虫(Ascaris suum)谷胱甘肽S-转移酶(glutathione S-transferase,GST)蛋白编码基因的结构特征及其B细胞抗原表位,采用反转录-聚合酶链反应(RT-PCR)扩增猪蛔虫GST蛋白编码序列(coding sequence,CDS),将纯化的DNA与pMD19-T载体连接并转化入JM109感受态细胞,并将阳性菌液测序后进行序列分析、结构预测和抗原表位预测。结果表明,获得的猪蛔虫GST蛋白CDS序列与参考基因(Y10613.1)相比,在第243和248位核苷酸处发生变异,并导致第83位氨基酸由甲硫氨酸(Met)变异为苏氨酸(Thr);其优势B细胞抗原表位可能位于肽段29-38、43-47、80-87、114-120、129-131、143-145、190-194、201-204区域内或附近,其中最可能位于肽段43-46和201-204区域内或附近。研究结果为猪蛔虫基因工程疫苗的研发奠定了理论基础,同时为后续猪蛔虫GST基因功能和耐药相关性研究提供了基础资料。     

Tumor necrosis factor-like cytotoxicity and anorexia in Ascaris suum infected pigs

Tumor Necrosis Factor-Like Cytotoxicity (TNF-LC) was examined in sera from 12 pigs experimentally infected with Ascaris suum. The difference of TNF-LC levels between eight infected and four uninfected controls was not significant. When an endotoxin challenge was intravenously administered 1 month after the first dose of A. suum, the levels of TNF-LC in the sera of infected pigs were one-third that of the controls 125 min post-challenge (PC). In a more detailed study on four infected and two uninfected control pigs, TNF-LC was monitored every 10-15 min until 125 min after endotoxin challenge. The TNF-LC levels in these pigs increased at 40 min PC, reached maximum in another 10-25 min and then decreased. This pattern was seen in all except one infected pig. The infected pigs showed milder shock symptoms and their serum TNF-LC levels returned to pre-challenge levels 30 min earlier than controls.     

Evaluation of Abattoir Inspection for the Diagnosis of Mycobacterium bovis Infection in Cattle at Addis Ababa Abattoir

Detailed postmortem examinations were conducted to evaluate the efficiency of meat inspection procedures and to determine the distribution of lesions in Mycobacterium bovis-infected cattle. The study involved routine inspection at slaughter, collection of tissues for detailed examination in the laboratory, and bacteriological examination to identify M. bovis. Additionally, a 10-year (1992--2001) meat inspection record was analysed to determine tuberculosis trends in the past decade. chi2-Test and simple regression were used to analyse the data. Out of 1350 cattle examined, 1.5% were found with tuberculous lesions. Routine abattoir inspection detected only 55% of cattle with confirmed lesions. Fifty-four per cent of tuberculous lesions were found in the lungs and thoracic lymph nodes, 23% in the lymph nodes of the head, and the remaining 23% in the mesenteric and other lymph nodes of the carcase. M. bovis was additionally isolated from an animal that had no gross lesions of tuberculosis. On average, the annual rate of whole-carcase condemnation due to generalized tuberculosis was 0.024% and it has increased annually by 0.34% over the past decade. The rate of whole-carcase condemnation indicates a high degree of TB transmission and requires immediate attention from both the economic and public health points of view. The lower sensitivity of routine abattoir inspection confirms the importance of improving necropsy procedures.     

云南贯众驱猪蛔虫活性成分的鉴定及其体外杀虫试验研究

通过研究云南贯众(Cyrtomium yunnanense)的化学成分,用硅胶和凝胶柱色谱进行分离,根据理化性质、波谱特征鉴定结构。结果从其甲醇提取物中分离并鉴定了4个化合物:山奈酚-3,7-a-L-二鼠李糖苷(Kaempferol 3,7-a-L-Dirhamnopyranoside)(1),山奈酚-3-a-L-(4-O-乙酰基)鼠李糖基-7-a-L-鼠李糖苷[Kaempferol3-a-L-(4-O-acetyl)rhamnopyranoside-7-a-L-rhamnopyranoside](2),山奈酚-3-a-L-(2,4-二乙酰基)鼠李糖苷-7-a-L-鼠李糖苷[Kaempferol3-a-L-(2,4-Di-O-acetyl)rhamnopyranoside-7-a-L-rhamnopyranoside](3),β-谷甾醇(β-Sitosterol)(4)。利用猪蛔虫24孔NUNC细胞培养板,对云南贯众中提取分离的四种化合物的抗蠕虫活性进行检测,并作离体毒理试验,利用纤毛虫检测器来计数死活虫卵。结果4个化合物中,化合物2效果最佳,其次是化合物4、化合物1,化合物3最差。4个化合物均为首次从云南贯众中分离得到的单体,化合物2有望开发成为一种新的驱蛔虫药。     

Genital Abnormalities of the Female Dromedary (Camelus dromedurius). An Abattoir Survey

Contents: Post-mortem examination of 1048 nonpregnant genital organs of female camels revealed gross abnormalities in 22 (2.1%). Ovarian abnormalities included bilateral hypoplasia (0.1%), ovarian teratomas (0.4%) and follicular cysts (0.9%). Segmental aplasia of the cervix with cystic dilation of the uterine horns was noted in 8 specimens (0.8%). Out of 467 pregnant genital organs examined left hydrosalpinx was observed in one organ .
Inhalt: Genitale Anomalien beim weiblichen Dromedar (camelus dromedarius). Eine Schlachthofstudie
Bei einer Untersuchung von 1048 Genitalorganen von nichttrachtigen, geschlachteten, weiblichen Kamelen wurden in 22 Fällen (2,1%) morphologische Anomalien festgestellt. Ovaranomalien bestanden in bilateraler Hypoplasie (0,1%), Teratome (0,4%) und Follikelzysten (0,9%). Segmentale Aplasie der Cervix mit zystischer Veergräβerung der Uterushörner wurden in 8 Fällen (0,s%) gefunden. Von 467 trächtigen Genitalorganen wurde nur in einem Fall eine linksseitige Hydrosalpinx beobachtet .