Gram-negative anaerobes in the intestinal flora of pigs

A differential count of the gram-negative, anaerobic, non sporeforming bacteria in different segments of the pig intestinal tract was performed in 2 groups of pigs. Seventy-seven strains were identified, belonging to 6 groups: Sphaerophorus necrophorus, anhemolytic Sphaerophorus spp., Bacteroides (Eggerthella) spp., Fusobactenum spp., Veillonella/Acidaminococcus spp., and Peptostreptococcus elsdenii. The characters of these groups are described, and quantitative data on their occurrence in a group of normal porkers and a group of pigs with experimental swine dysentery are given.     

A comparison of the efficacy of two ivermectin formulations against larval and adult Ascaris suum and Oesophagostomum dentatum in experimentally infected pigs

A study was conducted to evaluate and compare the efficacy of two injectable formulations of ivermectin (IVM-1 and IVM-2) at a dose rate of 0.3 mg/kg bodyweight versus placebo in the treatment and control of larval and adult stages of Ascaris suum and Oesophagostomum spp. in experimentally infected pigs. Seventy helminth free pigs were allocated on a liveweight basis to 7 groups each comprising 10 pigs (A-G). Group A served as an untreated control group. Groups B and C were used to investigate the efficacy of both formulations against adult stages of A. suum and Oesophagostomum spp., Groups D and E for efficacy against larval stages of A. suum and Groups F and G for efficacy against larval stages of Oesophagostomum spp. Pigs of groups A, B, C, D and E were infected on Day-0 with 1000 infective A. suum eggs each. Infective larvae of Oesophagostomum spp. (10,000/pig) were given on Day-0 to pigs of Groups F and G and on Day-21 to pigs of Groups A, B and C. Treatment was given to pigs of Group A (saline as placebo) on Day-7 and -28, IVM-1 to pigs of Group F on Day-7, pigs of Group D on Day-14 and pigs of Group B on Day-49. IVM-2 was given to pigs of Group G on Day-7, Group E on Day-28 and Group C on Day-49. Pigs of Groups F and G were sacrificed on Day-28, pigs of Groups A, D and E on Day-49 and pigs of Groups B and C on Day-56. Post mortem worm counts showed the following efficacies: (IVM-1) against larval A. suum 100%, against adult A. suum 94.4%, against larval Oesophagostomum spp. 52.0% and against adult Oesophagostomum spp. 83.0%. (IVM-2) against larval A. suum 100%, against adult A. suum 90.3%, against larval Oesophagostomum spp. 94.0% and against adult Oesophagostomum spp. 94.7%.     

Tylosin-responsive chronic diarrhea in dogs

Fourteen dogs had shown chronic or intermittent diarrhea for more than 1 year. Diarrhea had been successfully treated with tylosin for at least 6 months but recurred when treatment was withdrawn on at least 2 occasions. Tylosin-responsive diarrhea (TRD) affects typically middle-aged, large-breed dogs and clinical signs indicate that TRD affects both the small and large intestine. Treatment with tylosin eliminated diarrhea in all dogs within 3 days and in most dogs within 24 hours. Tylosin administration controlled diarrhea in all dogs, but after it was discontinued, diarrhea reappeared in 12 (85.7%) of 14 dogs within 30 days. Prednisone given for 3 days did not completely resolve diarrhea. Probiotic Lactobacillus rhamnosus GG did not prevent the relapse of diarrhea in any of 9 dogs so treated. The etiology of TRD, a likely form of antibiotic-responsive diarrhea (ARD) is unclear. The following reasons for chronic diarrhea were excluded or found to be unlikely: parasites, exocrine pancreatic insufficiency, inflammatory bowel disease, small intestinal bacterial overgrowth, enteropathogenic bacteria (Salmonella spp., Campylobacter spp., Yersinia spp., or Lawsoni intracellularis), and Clostridium perfringens enterotoxin and Clostridium difficile A toxin. A possible etiologic factor is a specific enteropathogenic organism that is a common resident in the canine gastrointestinal tract and is sensitive to tylosin but difficult to eradicate. Additional studies are required to identify the specific cause of TRD.     

Dietary Bacillus spp. enhanced growth and disease resistance of weaned pigs by modulating intestinal microbiota and systemic immunity

Background: Previous research has shown that dietary supplementation of Bacillus spp. probiotics exerts beneficial effects on animals' growth. However, limited studies have evaluated the efficacy of Bacillus spp. on weaned pigs and their effects on host gut health and microbiome, and systemic immunity using a disease challenge model. The objective of this experiment was to investigate the effects of two Bacillus spp. strains(Bacillus subtilis DSM 32540 and Bacillus pumilus DSM 32539) on growth performance, diarrhea, intestinal health, microbiome, and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli(ETEC).Results: Pigs in PRO1(Bacillus subtilis DSM 32540) had greater(P 0.05) body weight on d 7 and 14 PI, greater(P 0.05) ADG from d 0 to 7 and d 7 to 14 PI, compared with pigs in CON(Control). Pigs in PRO1 had milder(P 0.05)diarrhea on d 2 and 3 PI compared with pigs in CON. However, no differences were observed in growth performance and diarrhea score between PRO2(Bacillus pumilus DSM 32539) and CON groups. Supplementation of PRO1 decreased(P 0.05) lymphocyte counts on d 7 and 14 PI, compared with CON. Supplementation of PRO1 and PRO2 both reduced(P 0.05) total coliforms in mesenteric lymph nodes on d 21 PI. Pigs in PRO2 had greater(P 0.05) goblet cell number and sulfomucin percentage in duodenal villi and greater(P 0.05) sialomucin percentage in jejunal villi than pigs in CON. Supplementation of PRO1 up-regulated(P 0.05) MUC2 gene expression in jejunal mucosa and reduced(P 0.05) PTGS-2 and IL1 B gene expression in ileal mucosa on d 21 PI,compared with CON. Pigs in PRO1 had reduced(P 0.05) relative abundance of families Lachnospiraceae,Peptostreptococcaceae and Pasteurellaceae in the ileum.Conclusions: Supplementation of Bacillus subtilis DSM 32540 improved growth performance, alleviated diarrhea severity, enhanced gut health, and reduced systemic inflammation of weaned pigs infected with ETEC F18.Although Bacillus pumilus DSM 32539 was able to alleviate systemic inflammation, it had limited impacts on growth performance and severity of diarrhea of ETEC F18 challenged weaned pigs.     

Multiple feather follicle cysts in a Moroseta hen (Gallus gallus)

An 8-month-old white feathered, black skinned Moroseta hen was presented for examination because of numerous 2 mm- to 30 mm-diameter irregularly shaped, hard nodules in the skin of the head, wings, back, and abdomen. The nodules were confined to the skin and did not involve subcutaneous tissues. Nodules consisted of dilated feather follicles packed with a caseous tan-to-pale-yellow material admixed with feather remnants. Histologically, affected feather follicles were markedly dilated and filled with laminated keratin debris. Necrosis of the epidermis and perifollicular lymphocyte infiltration was also present. Bacteriologic investigation of internal organs was negative, while secondary bacteria, Proteus spp. and Bacillus spp., were isolated from skin nodules. A concomitant lice infestation of Menopon spp., as well as leg mange caused by Cnemidocoptes spp., were also present. These bacterial isolates and parasites were not related to the disease condition. The condition observed was differentiated from benign feather follicle tumors, and a diagnosis of multiple feather follicle cysts was made. In addition, a breed predisposition was hypothesized.     

Control of Isospora suis-induced coccidiosis on a swine farm

Results of a program designed to control neonatal porcine coccidiosis on a total confinement, farrow-to-finish swine farm are reported. The control program consisted of washing, phenol disinfection, and steam cleaning of farrowing houses and treatment of sows with amprolium HCl before and after farrowing. Before initiation of the control program, 88.9% of the sows examined in the farrowing house were negative for coccidian oocysts, 9.9% were positive for Eimeria spp, and 1.2% were positive for Isospora suis. Most pigs nursing on sows before initiation of the control program had diarrhea at 5 to 10 days of age, which led to dehydration and weight loss. Morbidity was high, and mortality was moderate. Composite fecal samples from these litters were all positive (100%) for I suis. After initiation of the control program, 99.6% of the sows examined in the farrowing house were negative for coccidian oocysts and 0.4% were positive for Eimeria spp. Clinical signs of coccidiosis were rarely present in nursing pigs examined after the control program was initiated; however, I suis was still present in 19.8% of the composite fecal samples from pigs examined. An association between oocyst production in sows and I suis infections in pigs was not found in the present study. Oocysts of Eimeria spp were not found in the feces from the pigs.     

The Prevalence of Aeromonas Species in Feces of Horses with Diarrhea

Feces collected from 40 horses with diarrhea and 34 horses without diarrhea were examined to determine if an association existed between isolation of Aeromonas spp. and diarrhea. Samples were also examined for Salmonella spp., and identification of viruses and parasite ova. Neither Salmonella spp. nor Aeromonas spp. were isolated from the feces of 34 control horses. Aeromonas spp. were isolated from feces of 22 of 40 (55%) horses with diarrhea. Salmonella spp. were isolated from feces of 8 (20%) horses, and of these, 5 (12.5%) were also positive for Aeromonas spp. Twenty-nine isolates of Aeromonas spp. were recovered from the feces of 22 diarrheic horses. Of these isolates, more than 80% were susceptible on in vitro testing to amikacin, ceftiofur, chloramphenicol, and gentamicin. All isolates were susceptible to enrofloxacin. Diarrheic horses positive for Aeromonas were significantly (P = .04) older than diarrheic horses negative for Aeromonas spp. A significantly greater number of fecal samples were positive for Aeromonas spp. during March through August than samples examined in other months (P = .014). Results of this study indicate that Aeromonas spp. should be considered as a cause of diarrhea in horses.     

Nosocomial diarrhea associated with enterotoxigenic Clostridium perfringens infection in dogs

A retrospective analysis of the medical records of 30 consecutive cases of diarrhea occurring in dogs that were hospitalized in a teaching hospital was performed. A prospective analysis of culture results for Clostridium perfringens of dogs with diarrhea were compared with those of a control nondiarrheal group. Hospital-acquired diarrhea in dogs was found to be associated with multiple serotypes of enterotoxigenic Clostridium perfringens. Other potential etiologic agents could not be isolated. Clinical signs were variable, and included mild depression, anorexia, and soft to watery diarrhea with or without frank blood, mucus, and tenesmus. Fever was not present. There were no hematologic or serum biochemical abnormalities, nor were there any consistent virologic or parasitologic findings. Salmonella spp or Campylobacter spp were not identified by fecal culture. No risk factors could be identified. A dog that was euthanatized on the day it developed diarrhea had intestinal histologic findings suggestive of clostridial enteritis. Dogs with diarrhea had significantly higher fecal clostridial counts than did dogs without diarrhea (mean log10 counts +/- SD = 6.34 +/- 1.79 vs 4.75 +/- 2.07). Enterotoxin was found in the feces of 41% of diarrheic dogs but in only 7% of dogs without diarrhea.     

Clinical coccidiosis in a boar stud.

This report describes an outbreak of coccidiosis in a boar stud. A live, untreated, adult boar with a history of diarrhea was submitted to the Iowa State University Veterinary Diagnostic Laboratory, Ames, IA. For a 3-month period, approximately 40% of the boars in this stud had developed gray to brown diarrhea that lasted 1-3 days. Affected boars did not lose condition, and antibiotic therapy did not appear to affect the clinical course ofthe disease. At necropsy, the distal ileum was palpably thickened and covered by a thick, yellow-green, fibrinous exudate. Microscopic changes in the ileum consisted of an erosive enteritis associated with the presence of numerous coccidia within mid to superficial villus enterocytes. The mucosa was covered by a fibrinous exudate admixed with numerous nonsporulated coccidian oocysts. A light growth of Salmonella enterica serovar Derby was isolated from the small intestine of this animal, but laboratory tests were negative for Lawsonia and Brachyspira spp. Individual or paired fecal samples were obtained from 6 additional boars experiencing similar clinical signs. Numerous Eimeria spinosa oocysts were identified in these samples. Neither Salmonella nor Brachyspira spp. were cultured from submitted fecal samples. Necropsy of a live boar and examination of feces from 6 additional animals confirmed that the mild, sporadic, transient diarrhea in this boar stud was due to coccidiosis.     

Pathogenicity of an attenuated strain of transmissible gastroenteritis virus for newborn pigs.

The pathogenicity of a cell culture-attenuated strain of transmissible gastroenteritis virus for newborn pigs was investigated. Newborn (1- to 2-day-old) pigs were orally given 2 x 10(6) plaque-forming units of attenuated virus. All pigs developed mild diarrhea, but deaths did not occur. As determined by immunofluorescence and villous atropy, infection of the small intestine was limited to the caudal 50 to 66%. Fluorescing cells and atrophic villi were seen from 2 to 3 days until 6 to 7 days after exposure. Attenuated virus-exposed pigs produced circulating virus-neutralizing antibodies detectable as early as 5 days after exposure. By contrast, all pigs orally given 1 x 10(2) pig infective doses of virulent transmissible gastroenteritis virus developed severe diarrhea, and almost all of those not killed died within 2 to 5 days after exposure. In the latter pigs, the entire length of the small intestine, except for the first 4 to 5 cm, was infected with virus by 24 to 36 hours after exposure.     

Isolation of porcine epidemic diarrhea virus in porcine cell cultures and experimental infection of pigs of different ages

This paper describes the isolation of porcine epidemic diarrhea (PED) virus in Vero and porcine cell cultures, and the influence of age on disease in experimental infection. PED virus was isolated from the small intestine of piglets inoculated with PED samples and cultured in Vero, porcine bladder and kidney cells propagated in collagen-coated tissue culture plates in maintenance medium (MM) containing trypsin. In porcine bladder and kidney cell cultures inoculated with isolated PED virus, cytopathic effects (CPE) including cell fusion were detected. Specific brilliant fluorescence was observed in the cytoplasm of these cells. Two- and 7-day old, and 2-, 4-, 8- and 12-week old specific pathogen-free (SPF) pigs were orally inoculated with PED virus isolated from an outbreak. All 2- and 7-day old pigs inoculated developed severe watery diarrhea from post-inoculation day (PID) 1 and died between PID 3 and 4. Although three of five 2-week old pigs developed diarrhea on PID 1-4, they eventually recovered. In the 4-week old group, three of five pigs had mild diarrhea for 1-2 days. None of the 8- and 12-week old pigs showed any clinical signs. Antibodies against PED virus were detected in all surviving pigs by virus neutralization (VN) test and immunofluorescence assay (IFA). Therefore, there is an age-dependent resistance to pathogenic PED virus infection in pigs.     

Survey of intestinal parasites in pigs from intensive farms in Guangdong Province, People's Republic of China

The prevalence of intestinal parasites was investigated in intensive pig farms in Guangdong Province, China between July 2000 and July 2002. Faecal samples from 3636 pigs (both sexes and five age groups) from 38 representative intensive pig farms employing different parasite control strategies were examined for the presence of helminth ova and protozoan oocysts, cysts and/or trophozoites using standard techniques. Of the 3636 pigs sampled, 209 (5.7%) were infected with Trichuris suis, 189 (5.2%) with Ascaris, 91 (2.5%) with Oesophagostomum spp., 905 (24.9%) with coccidia (Eimeria spp. and/or Isospora suis) and 1716 (47.2%) with Balantidium coli. These infected pigs were mainly from farms without a strategic anti-parasite treatment regime. Concurrent infection of multiple parasites was common, and T. suis was the most common nematode infecting breeding, young and mature pigs. The results of the present investigation provide relevant 'base-line' data for assessing the effectiveness of control strategies against intestinal parasitism in intensively raised pigs in Guangdong Province, China.     

Coinfection with multiple tick-borne and intestinal parasites in a 6-week-old dog

Coinfection with Ehrlichia canis, Babesia canis, Hepatozoon canis, Isospora spp., Giardia spp., and Dipylidium caninum were detected in a 6-week-old dog. The effect of multi-pathogen infection was a fatal combination of gastrointestinal and hematologic abnormalities, including diarrhea, vomiting, anorexia, distended painful abdomen, intussusception, severe thrombocytopenia, anemia, and hypoproteinemia.     

Neonatal Diarrhea of Pigs in Quebec: Infectious Causes of Significant Outbreaks

To evaluate the relative importance of the various enteropathogens causing neonatal diarrhea in Quebec farrowing operations, observations were made on 749 diarrheic pigs from 325 outbreaks of diarrhea. They were one to 15 days of age, and were obtained alive for necropsy generally within 48 hours of the onset of diarrhea. Some pigs were from severe, explosive outbreaks of diarrhea with high morbidity and mortality rates, while others were from herds with chronic neonatal diarrhea with lower morbidity and mortality rates. A combination of bacteriological, virological and histological methods were used to study the pigs.

Viruses were incriminated in 60%, bacteria in 23% and coccidia in 15.3% of the 325 diarrhea outbreaks. Transmissible gastroenteritis virus was by far the most common enteropathogen with a prevalence of 52%; rotavirus was implicated in 9.2% of the outbreaks while adenovirus was incriminated in 0.30% of the outbreaks. Enterotoxigenic Escherichia coli were involved in 22.4% of the cases while Clostridium perfringens type C was an occasional finding. Coccidia involved in our herds were identified as Isospora suis. The disease was attributed to infection with a single etiologic agent in 590 diarrheic pigs (78%) while combinations of agents were present in only 90 (12%).

The age-specific occurrence of the various enteropathogens was evaluated. Transmissible gastroenteritis virus was the most common enteropathogen in all age groups. Colibacillosis was common in pigs which became diarrheic under five days of age; in this age group, the enterotoxigenic E. coli were frequently found alone, but were usually combined with other agents in older pigs. The prevalence of coccidia was high in pigs which became diarrheic between five and 15 days of age. Rotavirus infection was common in diarrheic pigs older than ten days of age. Although individual baby pigs were commonly infected with a single enteropathogen, it was very common to see more than one agent involved in an outbreak of diarrhea, particularly when pigs of different ages were affected.

Observations on the occurrence of the enteropathogens according to the seasons were also made. Occurrence of transmissible gastroenteritis was throughout the year with the highest prevalence during the fall, winter and spring months. Colibacillosis and coccidiosis were more common in the summer, fall and early winter months with the lowest prevalence in the spring months.

     

Leishmaniosis in a cat with chronic diarrhea as the only clinical manifestation

A 10‐year‐old male domestic shorthaired cat was presented with chronic diarrhea unresponsive to treatment. Laboratory testing identified hyperglobulinemia and mild nonregenerative anemia, and nongastrointestinal causes of diarrhea were ruled out. Gastrointestinal endoscopy and biopsy were performed and disclosed diffuse generalized granulomatous and lymphoplasmocytic inflammatory reaction in all segments of gastrointestinal tract evaluated, with numerous Leishmania spp. amastigotes within the cytoplasm of macrophages. The organism also was detected in spleen and bone marrow and Leishmania spp. serology was positive (immunofluorescence assay 1 : 160). A diagnosis of granulomatous enteritis secondary to leishmaniosis was made. Gastrointestinal signs resolved after treatment with allopurinol and a dietary supplement of nucleotides and active hexose‐correlated compounds (N‐AHCC), but seropositivity and gammopathy persisted 8 months later. The cat died of unrelated causes after an additional 3 months and permission for necropsy was not granted. Leishmaniosis as a cause of chronic diarrhea has not been reported previously in cats and should be considered in endemic areas in cats with chronic gastrointestinal signs.     

Parasites of domestic and wild animals in South Africa. VII. Helminths in pigs slaughtered at the Pretoria municipal abattoir

A total of 52 pigs slaughtered at the Pretoria Municipal Abattoir over a period of 1 year was examined for parastitic helminths. Twenty-six of these pigs were marketed by farmers and 26 by speculators. Of the pigs marketed by farmers 73,1% were found to be infested:--30,8% with Ascaris suum, 65,4% with Ascarops strongylina, 3,8% with Metastrongylus apri, 26,9% with Oesophagostomum spp., 15,4% with Trichostrongylus colubriformis and 15,4% with Trichuris suis. All the pigs marketed by speculators were infested:--7,7% with A. suum, 92,3% with A. strongylina, 11,5% with Oesophagostomum spp., 65,4% with Physocephalus sexalatus, 7,7% with T. colubriformis and 11,5% with T. suis. The findings obtained in surveys conducted in Canada, Greece, India, the Philippines, the United Kingdom and the United States of America are quoted for comparison. Trichostrongylus colubriformis and Oesophagostomum quadrispinulatum are recorded for the first time in pigs in the Republic of South Africa.     

荣昌县生猪肠道寄生虫感染情况调查

目的摸清重庆市荣昌县生猪的肠道寄生虫感染情况,从而为有效防控猪的肠道寄生虫感染提供依据。方法荣昌是我国著名地方猪“荣昌猪”的故乡,我国养猪大县之一,作者于2007年4月至2007年11月,在该县20个镇选择具有代表性的规模化猪场、散养户和屠宰场,对种公猪、母猪、仔猪及肥育猪肠道寄生虫感染情况和屠宰场宰杀的肥猪肠道寄生虫虫体感染情况进行了调查。共检查了832份集约化饲养猪的粪便、l133份农户散养猪的粪便,并检查了200头屠宰肥猪的肠道。结果13．1％的集约化饲养猪感染猪蛔虫,5．4％感染猪鞭虫．14．6％感染食道口线虫,14．8％感染球虫（包括艾关尔球虫及等孢球虫）,3．6％感染结肠小袋纤毛虫。对散养猪．这些数值分别是6．7％,4．8％,23．2％,13．8％,及4．9％。4％的宰杀肥猪检出猪蛔虫,3．5％检出猪鞭虫,52．0％感染食道口线虫。混合感染很常见。结论本项调查表明,荣昌生猪的寄生虫感染较为严重,应引起有关方面的足够重视。应尽快开展猪肠道寄生虫感染的综合防控工作,以保障养猪业的健康快速发展。     

The use of a mimic to detect polymerase chain reaction-inhibitory factors in feces examined for the presence of Lawsonia intracellularis.

Lawsonia intracellularis is an intracellular organism that causes proliferative enteritis in pigs. This bacterium is difficult to culture, and antemortem demonstration of the microbe is therefore often performed on fecal samples by polymerase chain reaction (PCR). Polymerase chain reaction is sensitive and specific, but inhibitory factors in feces might cause false-negative results. This article describes the construction and use of an internal standard, a mimic. The mimic is amplified by the same primers as those used for L. intracellularis DNA and thus could indicate false-negative results in clinical samples. The amplicon was clearly visible when as few as 10 mimic molecules were added per amplification reaction and when no inhibitors werepresent. When fecal samples were spiked with the mimic, the detection limit was 10(2) molecules per PCR. Sixty clinical samples, 20 from wild boars, 20 from growing pigs with diarrhea, and 20 from pigs without diarrhea, were prepared by a boiling procedure and subjected to PCR together with 10(3) mimic molecules. Nine samples were positive, of which 7 originated from pigs with diarrhea and 2 from pigs without diarrhea. In 14 samples from wild boars, in 8 samples from pigs without diarrhea, and in 3 samples from pigs with diarrhea, neither the mimic nor the target DNA was visible. This indicated the presence of inhibitors in these samples. It is concluded that the mimic can be used as an internal control in the diagnosis of L. intracellularis to indicate inhibition of PCR.     

Effect of Streptococcus faecium C-68 in control of Escherichia coli-induced diarrhea in gnotobiotic pigs

Streptococcus faecium was fed to prevent colibacillosis in gnotobiotic pigs. Three strains of Escherichia coli were used. With strain O:K103, 987P:NM in pigs fed S faecium before the E coli challenge exposure, the pigs exhibited less severe diarrhea, recovered earlier, and produced better weight gains than did pigs given E coli only. Escherichia coli strains O157:K88ac:H19 and O8:K87, K88ab:H19 were more virulent. Pigs fed S faecium and challenge exposed with these 2 strains of E coli developed mild diarrhea; however, none of the pigs died, and they continued to eat well and gained weight. Pigs given E coli only developed severe diarrhea and lost weight, and 5 of 8 infected pigs died. Bacterial counts of E coli and S faecium from 3 areas of the small intestine and the cecum were all comparable among experimental groups. Histopathologic examinations demonstrated abundant colonization of the intestinal tract with S faecium. Seemingly, S faecium reduced the toxic effects of E coli and prevented generalized infection and death.     

一例高致病性猪蓝耳病、猪流行性腹泻混合感染的诊断

2018年11月,湖南郴州某规模化猪场发生2~3日龄仔猪呕吐、腹泻为主的疫情,发病率70%,死亡率80%,为确定引起仔猪腹泻的原因,从发病猪群中采集2头病死猪的小肠、肺脏、淋巴结等组织进行PCR检测及基因测序分析。检测结果显示猪流行性腹泻和猪蓝耳病均为阳性,猪传染性胃肠炎、猪轮状病毒均为阴性。测序分析显示所检测到的猪蓝耳病病毒与JXA1毒株高度同源,为高致病性毒株,检测到的猪流行性腹泻病毒为变异毒株,隶属于GⅡ-b群。综合分析,引起此次新生仔猪大批死亡系变异猪流行性腹泻病毒混合感染高致病性猪蓝耳病所致。