Ascaris suum in Saskatchewan Pigs: An Abattoir Survey of Prevalence and Intensity of Infection

In a survey of 2500 market weight pigs in a Saskatchewan abattoir, 37% were infected with adult Ascaris suum and in 46% there were milkspot hepatic lesions. A total of 60% of the pigs examined had some evidence of A. suum infection. Most infected pigs contained less than 50 adult ascarids.

In a second abattoir survey of a further 2500 market weight pigs, 44% of the animals had milk-spot hepatic lesions. In approximately 12% of the affected pigs these lesions were very severe and a very similar proportion of pigs' livers were condemned or sent for use as animal feed.

The results of these surveys are discussed with particular reference to the significance of A. suum infection in growing pigs in Saskatchewan.

     

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.     

Hepatic lesions caused by migrating larvae of Ascaris suum in chickens

Group A consisted of chickens infected with a single dose of Ascaris suum and group B of chickens infected with two successive doses. At days 1, 3, 7, 14 and 21 after the first or second infection dose, six chickens from each group were sacrificed. In both groups, larvae were recovered from the livers on days 1, 3, and 7 and lungs on days 3 and 7. No larvae were detected in chickens on day 14. Clear white lesions were noticed only on the livers from chickens of group B at day 7 but had disappeared at day 14. A comparison with group B showed mild histological changes that developed relative to the livers from group A.     

Sequential development of esophagogastric ulcers induced in swine by infections with Ascaris suum goeze, 1782

Twenty-five experimental and five control hysterectomy derived pigs were raised colostrum free under specific pathogen-free conditions. The experimental pigs were first inoculated with A. suum eggs at 8 weeks of age, and a second dose of infective eggs was given 15 days later. They were necropsied from 4 to 10 days post second infection.The ulcers found in the stomach of these pigs were confined to the esophagogastric area. A sequence of epithelial changes, erosions, and ulceration was seen in the stratified squamous epithelium. Edema and hemorrhage were noted in the lamina propria and submucosa. Vascular changes in the area were characterized by thickening of the wall and presence of thrombi in arteries as well as cellular degeneration and vacuolization of the media and intima of the veins.Changes in the muscularis were characterized by edema and degeneration of the muscle cells, which later were replaced by fibroblasts and heavy infiltration by eosinophils.Three of the control pigs received one dose of A. suum eggs, and were killed one on each of the 8th, 9th, and 10th days post infection. The remaining two pigs received no infective material and were killed when they were 11 weeks of age. Neither the uninoculated pigs nor the once-inoculated animals developed ulcerations in their stomachs.The possible mechanisms by which esophagogastric lesions are produced following A. suum larval migrations are discussed.     

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.     

Establishment of Ascaris suum in the pig: development of immunity following a single primary infection

Development of immunity after a single primary infection of Ascaris suum in pigs was investigated with regard to the worm population dynamics of a superimposed A. suum infection, host immune response and gross liver pathological changes. Group A was given a primary infection of 60,000 infective A. suum eggs and group B was left uninfected. Four weeks later both groups A and B were inoculated with 1,000 A. suum eggs, and subgroups were slaughtered 7, 14 and 21 days post challenge infection (p.c.i.). An uninfected control group C was slaughtered on day 21 p.c.i. The challenge worm recovery in group A was reduced compared to group B by 12%, 50% and 75% on day 7, 14 and 21 days p.c.i., respectively. In both groups was the expulsion of worms initiated between day 14 and 21 p.c.i. However, in group A the worms were recovered more posteriorly in the small intestine and 21 days p.c.i. the mean worm length was significantly shorter than in group B (p = 0.01). The results above were associated with significantly higher (p < 0.05) antibody response and higher eosinophil counts in group A compared to group B. The present results suggest that the larval growth and survival of a challenge infection are decreased, probably due to higher antibody and eosinophil attack during the migratory phase.     

参虎败毒颗粒体内抗猪繁殖与呼吸综合征病毒的效果观察

为探究参虎败毒颗粒抗猪繁殖与呼吸综合征病毒（PRRSV）的作用,将20头PRRSV阴性仔猪随机平均分为4组,即提前药物处理感染组（A组）、感染同时药物处理组（B组）、无药物处理感染组（C组）和无药物处理不感染组（D组）。A和B组分别于攻毒前3 d和攻毒时在基础日粮中添加参虎败毒颗粒（每头10 g·d^-1）,连续饲喂至攻毒后28 d,每日测量体温,在攻毒后第14天,每组随机处死仔猪1头,观察病理变化,RT-qPCR检测肺组织病毒载量,并在攻毒后第1、3、5、7、14、21、28、35天采全血和血清样品进行PRRSV核酸和抗体检测。结果发现,A和B组仔猪体温在攻毒后第6天上升至40℃以上,第12天时恢复正常;C组仔猪体温在第5天上升至40℃以上,持续至试验结束仍未恢复。A、B组仔猪肺组织病变较轻,肺泡结构轻度损伤,支气管内有少量炎性渗出物,周围有少量炎性细胞浸润;C组仔猪肺组织病变严重,肺泡结构破坏严重,支气管内有大量炎性渗出物和炎性细胞浸润。A组在攻毒后3、5、7和14 d病毒载量极显著低于C组（P<0.01）;B组在攻毒后3和5 d病毒载量极显著低于C组（P<0.01）,第7和14天病毒载量显著低于C组（P<0.05）。A、B组PRRSV抗体在攻毒后第21天达到峰值,C组在28 d达到峰值。以上结果可知,参虎败毒颗粒能够显著减轻PRRSV造成的仔猪肺部病理损伤,降低病毒血症;添加药物可使PRRSV特异性抗体峰值提前,减少病毒血症持续时间,证明参虎败毒颗粒可用于预防或治疗PRRSV感染,降低PRRSV对仔猪的影响。     

Consequence of Cryptosporidiosis on the immune response of vaccinated broiler chickens against Newcastle disease and/or avian influenza

The consequence of cryptosporidiosis on the immune response of vaccinated chickens against Newcastle disease and/or avian influenza was studied by using 240, 1 day old, male, white Hy-Line chicks and divided into 8 groups and subgroups. Each group or subgroup was consisting of 30 chicks (15?×?2 replicates). The first and second groups were kept as unvaccinated control, G1uninfected and G2 infected. G3, G4 and G5 contained 2 subgroups A&B (G3A, G3B, G4A, G4B, G5A and G5B). Chicks of subgroup A were vaccinated only while chicks of subgroup B were infected and vaccinated. These chicks were orally inoculated with 5?×?10⁵ oocysts of Cryptosporidium baileyi (C. baileyi) at 2 days of age. Chickens were vaccinated intraocular with live Newcastle disease (ND) vaccine (Hitchner on day 7th and LaSota on day 17th of chicken life) (G3) or vaccinated by subcutaneous route with Volvac®- H5N2- AI vaccine on day 10 of chicken life (G4). Last group (G5) was infected similarly and vaccinated with ND and AI vaccines with the same day, dose and route of vaccination for each one. Random blood samples were collected for 3 weeks post-vaccination for investigation of humoral immune response against Newcastle and/or avian influenza vaccines by the haemagglutination inhibition (HI) test. The results showed that H5N2 vaccine at day 10 of chicken life is effective in chickens indicated by the geometric mean of HI titer against AI virus. The findings of this study showed that the infection with Cryptosporidia in the broiler chicken has a depressive effect on the immune status of the birds vaccinated against ND and/or AI vaccination. Moreover, the obtained protection rates against challenge with virulent ND virus observed to be parallel to the results of HI- test. Also, by using 2 different antigens (one commercial and field prepared antigen) to avian influenza virus, lower Geometric mean (GM) HI titer were appeared in infected and vaccinated group than vaccinated group only. A study of the relative lymphoid organs weight such as bursa of Fabricius from the experimental chicks indicated that those organs were comparable between the groups infected-vaccinated and vaccinated only. Non significant variations in final live weight between uninfected control and infected groups were indicated. Also, H5N2-AI vaccination at 10 days old did not affect the final live weight. ND and/or AI Vaccination could not be a substitute to application of good hygienic measures and fecal examination of the birds especially for protozoal diseases such as cryptosporidiosis. It could be concluded that cryptosporidiosis could be one cause of ND and/or AI vaccination failure in poultry farms.     

Efficacy of a single high oxfendazole dose against gastrointestinal nematodes in naturally infected pigs

The goal of the current experiment was to assess the clinical efficacy of oxfendazole (OFZ) administered as a single oral dose (30 mg/kg) to pigs naturally parasitized with Ascaris suum, Oesophagostomum spp., Metastrongylus spp. and Trichuris suis. Thirty-six local ecotype piglets were divided into three independent experiments, named I, II and III (n = 12 each), respectively. Each experiment involved two different groups (n = 6): Untreated Control and OFZ treated. Animals were naturally parasitized with A. suum (Experiments I, II and III), Oesophagostomum spp. (Experiments I and II), T. suis (Experiments II and III) and Metastrongylus spp. (Experiment I). Pigs in the treated group received OFZ (Synanthic^®, Merial Ltd., 9.06% suspension) orally at 30 mg/kg dose. At five (5) days post-treatment, animals were sacrificed and the clinical efficacy of the OFZ treatment was established following the currently available WAAVP guidelines for a controlled efficacy test. None of the animals involved in this experiment showed any adverse events during the study. OFZ treatment given as a single 30 mg/kg oral dose showed a 100% efficacy against all the nematode parasites present in the three experiments. In conclusion, under the current experimental conditions, OFZ orally administered to naturally parasitized piglets at a single dose of 30 mg/kg was safe and highly efficacious (100%) against adult stages of A. suum, Oesophagostomum spp., T. suis and Metastrongylus spp.     

Health and performance of commingled feeder pigs as affected by lincomycin and carbadox

Purchased feeder pigs from 12 farms were commingled and divided into three treatment groups of carbadox, lincomycin and controls. Health and performance evaluations included serology, bacterial isolations, fecal examinations and post-mortem examinations at slaughter, weight gain, and feed efficiency.Serological tests for influenza, Aujeszky's disease and Mycoplasma hyopneumoniae were negative throughout the study. Bordetella bronchiseptica was isolated from 14% of the pigs on arrival and from 42% of the pigs 30 days after commingling. No Salmonella spp. were isolated from fecal swabs on arrival; Salmonella typhimurium was isolated from 2.5% of the pigs on Day 30, but no Salmonella was isolated on Day 90. Fecal examination on arrival revealed that 12.5% were infected with gastrointestinal parasites (5.0% Trichuris suis, 5.0% Ascaris suum and 2.5% Strongyloides ransomi).During the 30-day treatment period immediately following purchase and commingling, carbadox and lincomycin improved growth rate by 7.6% and 10.2%, respectively. The treatments also improved feed efficiency, by 9.9% and 5.7%, respectively, and uniformity of growth. Growth rate and feed efficiency were not affected by treatment from Days 30 to 90 following removal of the feed additives from the diet.Growth rate varied greatly, depending on the farm of origin. Although the reasons for the differences in performance were not well established, results suggested that transmission of B. bronchiseptica between pigs resulted in decreased growth rate following infection. Carbadox was significantly more effective than lincomycin in preventing transmission of B. bronchiseptica between commingled pigs.Post-mortem examination at slaughter revealed turbinate atrophy in 5.8% of the noses and pneumonia in 18% of the lungs. One liver exhibited evidence of ascarid larval migration. Treatments produced no significant effect (P>0.05) on post-mortem examination results.     

Effects of Salmonellosis on subsequent infections with Ascris suum in swine

Weanling pigs were exposed to Salmonella cholerae-suis var. kunzendorf and sixteen days later were inoculated with infective Ascaris suum eggs. Necropsy at seventeen days post-Ascaris-infection revealed fewer lesions of hepatic fibrosis and a lesser degree of tissue eosinophilia in the hepatic interstitium in pigs receiving inoculations of Salmonella and Ascaris compared to those receiving Ascaris inoculation only. The numbers of juvenile nematodes recovered from the small intestines of both groups were variable. The comparatively less-intensive hepatic lesions may have been caused by reduction of the number of penetrating larvae at the intestinal level. Alternatively, the decreased tissue eosinophilia and fibrosis of the liver may be due to the previous stress of the Salmonella infection.     

Retrospective study on the occurrence of the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus spp. in endemic areas of Italy

Aelurostrongylus abstrusus is a metastrongyloid nematode infesting the respiratory system of domestic cats worldwide. Troglostrongylus brevior and Troglostrongylus subcrenatus, two lungworms thought to infest wild felids, have been found recently in domestic cats from Spain and Italy. These unexpected findings have raised doubts about the assumed past and present occurrence of Troglostrongylus spp., especially T. brevior, in domestic hosts and suggest that there may have been missed detection or misdiagnosis. The present retrospective study evaluated the presence of lungworms in cats from Italy with a diagnosis of respiratory parasitism or with compatible lung lesions from 2002 to 2013. Sixty-eight samples of DNA and larvae from cats with a diagnosis of aelurostrongylosis, and 53 formalin-fixed paraffin-embedded lung samples from cats confirmed as lungworm infested or with compatible lesions, were investigated using two DNA-based assays specific for A. abstrusus or T. brevior. All DNA and larval samples were positive for A. abstrusus and one was additionally positive for T. brevior. Most paraffin-embedded lung tissues were positive only for A. abstrusus, but two samples tested positive for both lungworms and one for T. brevior only. This study supports the major role of A. abstrusus in causing feline respiratory parasitism in endemic areas of Italy.     

Comparison of parasite-specific immunoglobulin levels in two chicken lines during sustained infection with Ascaridia galli

Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth infections influence chicken health negatively, which is why the following investigation has been performed.In the present experiment, 20 chickens of two inbred chicken lines containing the major histocompatibility complex (MHC) haplotypes, B14 and R5, were inoculated with 500 embryonated Ascaridia galli eggs. The A. galli-specific IgG titres of serum samples and the excretion of A. galli eggs in chicken faeces were measured for a period of 81 weeks.The level of excreted A. galli eggs measured as eggs per gram chicken faeces (EPG) varied greatly between chickens in each line. Significant differences were found between the two lines and with the R5 chickens reaching the highest levels. Likewise, the A. galli-specific IgG titres in serum differed significantly between the two lines, and an inverse relationship between infection level (EPG) and antibody titres was found. Although this inverse relationship suggests that humoral immunity may be involved in protection against A. galli infection, the high antibody titres did not prevent continued infection.     

Indirect fluorescent antibody and complement fixation tests in the diagnosis of bovine theileriosis and babesiosis in Japan

Antibodies against Theileria sergenti and Babesia ovata were detected by indirect fluorescent antibody (IFA) and complement fixation (CF) methods. Both of the antibodies against T. sergenti and B. ovata could be detected with a single IFA testing procedure. Complement fixing antibody tests for T. sergenti in experimentally infected cattle were positive for about 70 days after the parasites could no longer be detected in the blood smear, and were negative thereafter. B. ovata CF antibody titres were negative on the 270th day post-infection, while the IFA tests against both parasites were positive for longer periods. B. ovata IFA-test titres remained relatively high until the 420th day after inoculation. In a survey of sera from naturally infected animals, the rate of detecting antibodies against both parasites was higher using the IFA test than using the CF test. The IFA method was more effective for diagnosis of Babesia infection than the CF technique.     

A systematic study of Tupaia as a model for human acute hepatitis B infection

The molecular features of hepatitis B virus (HBV) infection, eradication, and pathogenesis are poorly understood, partly due to the lack of an adequate animal model that faithfully reproduces the course of infection. Although Tupaia belangeri were previously recognized as HBV-susceptible animals, the course of infection in adult tupaias remains obscure. Herein, we performed a longitudinal study and demonstrated that adult tupaias were efficiently infected (90% infection rate) with 10⁸ copies of the HBV genome. HBV replicated vigorously, produced high levels of covalently closed circular DNA (cccDNA) in hepatocytes, and released hepatitis B surface antigen (HBsAg), hepatitis Be antigen (HBeAg), and HBV DNA into the serum at day 9 post-inoculation (p.i.), which then decreased on day 15 p.i. The kinetics were consistent with the expression of liver HBsAg and HBeAg, as determined with immunohistochemistry. The viral products in serum at day 9 and 15 p.i. represented de novo synthesized viral products, as treatment with a viral entry inhibitor completely abolished these products from the serum. Viral clearance and serological conversion occurred at day 21 p.i. and were accompanied by elevated alanine transaminase (ALT) levels and liver pathology, such as inflammatory infiltration and hepatocyte ballooning degeneration. Although ALT levels eventually returned to normal levels by day 42 p.i., the liver pathology persisted until at least day 120 p.i. The HBV infection process in tupaia, therefore, exhibits features similar to that of human acute HBV infection, including viral replication, viral eradication, ALT elevation, and liver pathology. Thus, adopting the tupaia model to study host-HBV interactions presents an important advance which could facilitate further investigation and understanding of human HBV infection, especially for features like cccDNA that current small-animal models cannot effectively model.     

Role of Bibersteinia trehalosi, respiratory syncytial virus,and parainfluenza-3 virus in bighorn sheep pneumonia

Pneumonic bighorn sheep (BHS) have been found to be culture- and/or sero-positive for Bibersteinia trehalosi, respiratory syncytial virus (RSV), and parainfluenza-3 virus (PI-3). The objective of this study was to determine whether these pathogens can cause fatal pneumonia in BHS. In the first study, two groups of four BHS each were intra-tracheally administered with leukotoxin-positive (Group I) or leukotoxin-negative (Group II) B. trehalosi. All four animals in Group I developed severe pneumonia, and two of them died within 3 days. The other two animals showed severe pneumonic lesions on euthanasia and necropsy. Animals in Group II neither died nor showed gross pneumonic lesions on necropsy, suggesting that leukotoxin-positive, but not leukotoxin-negative, B. trehalosi can cause fatal pneumonia in BHS.     

雏鸡感染传染性法氏囊病病毒时血细胞动态变化

研究了感染ＩＢＤＶ免疫和未免疫３０～５９日龄ＡＡ雏鸡的外周血细胞动态变化。结果表明：ＩＢＤＶ对红细胞数（ＲＢＣ）影响各组差异不显著,均随日龄增长呈上升趋势;从以ＩＢＤＶ攻毒前１ｄ到攻毒后的头５ｄ,３组鸡的白细胞数（ＷＢＣ）均呈上升趋势,未免疫未攻毒鸡（Ｃ组）随后下降,而未免疫攻毒鸡（Ａ组）和免疫攻毒鸡（Ｂ组）则持续上升至攻毒后第７ｄ,然后下降;Ａ组在ＩＢＤＶ攻毒后,白细胞分类计数（ＤＣ）中的单核细胞和异嗜性粒细胞急剧增加,淋巴细胞第１ｄ虽有减少但随后上升,嗜碱性粒细胞和嗜酸性粒细胞第７ｄ出现峰值,以后下降。方差分析显示,Ａ组ＷＢＣ和ＤＣ均高于或显著高于Ｂ组和Ｃ组,Ｂ、Ｃ两组比较,差异不明显。     

Immunogenicity of adenovirus and DNA vaccines co-expressing P39 and lumazine synthase proteins of <Emphasis Type="Italic">Brucella abortus</Emphasis> in BALB/c mice

Brucella poses a great threat to animal and human health. Vaccination is the most promising strategy in the effort to control Brucella abortus (B. abortus) infection, but the currently used live vaccines interfere with diagnostic tests and could potentially result in disease outbreak. Therefore, new subunit vaccines and combined immunization strategies are currently under investigation. In this study, immunogenicity and protection ability of a recombinant adenovirus and plasmid DNA vaccine co-expressing P39 and lumazine synthase proteins of B. abortus were evaluated based on the construction of the two molecular vaccines. Four immunization strategies (single adenovirus, single DNA, adenovirus/DNA, DNA/adenovirus) were investigated. The results showed that the immunization strategy of DNA priming followed by adenovirus boosting induced robust humoral and cellular immune responses, and it significantly reduced the numbers of B. abortus in a mouse model. These results suggest that it could be a potential antigen candidate for development of a new subunit vaccine against B. abortus infection.     

Dietary Bacillus subtilis C-3102 Supplementation Enhances the Exclusion of Salmonella enterica from Chickens

Among the reported probiotic Bacillus strains, B. subtilis C-3102 has the unique potential to improve feed uptake under stress conditions in the broilers, piglets, and cows. In this study, we sought to evaluate the protective effect of feed additive probiotic Bacillus subtilis C-3102 against Salmonella enterica infection of specific pathogen-free (SPF) chicks in floor pens in two experiments. In the experiment-1, the chicks in the control group (n=32) were fed a basal diet and those in the C-3102 group (n=32) were fed a basal diet supplemented with 1×10⁶ CFU/g of feed for 28 days. On day 7 post-challenge with S. enterica, there was no significant change in the body weight between both the groups throughout the test period, whereas detection rates of S. enterica in the C-3102 group were significantly lower in the cecum and liver on days 21 and 14 post-challenge, respectively. In the experiment-2, minimum dosage of C-3102 cells required to protect Salmonella infection was evaluated using 3 dosages. Chicks were divided into four groups, fed with different dosages of C-3102 (1×10⁶, 5×10⁵, 3×10⁵, and 0 CFU/g of feed), and challenged with S. enterica (2.8×10⁸ CFU/chicken). S. enterica infection was completed within 7 days post- challenge and was almost excluded from the liver and spleen on day 21 post- challenge in the control group. Average values showed a trend for higher infection rates in the control group >3×10⁵>5×10⁵>1×10⁶ CFU/g on days 14 and 21 post-challenge. These results suggest that B. subtilis C-3102 supplementation has the potential to reduce S. enterica infection rates and/or to accelerate the exclusion of S. enterica from the chicks.