Calf diarrhea is a commonly reported disease in young animals, and still a major cause of productivity and economic loss to cattle producers worldwide. In the report of the 2007 National Animal Health Monitoring System for U.S. dairy, half of the deaths among unweaned calves was attributed to diarrhea. Multiple pathogens are known or postulated to cause or contribute to calf diarrhea development. Other factors including both the environment and management practices influence disease severity or outcomes. The multifactorial nature of calf diarrhea makes this disease hard to control effectively in modern cow-calf operations. The purpose of this review is to provide a better understanding of a) the ecology and pathogenesis of well-known and potential bovine enteric pathogens implicated in calf diarrhea, b) describe diagnostic tests used to detect various enteric pathogens along with their pros and cons, and c) propose improved intervention strategies for treating calf diarrhea.
Animals ; Cattle ; *Cattle Diseases/diagnosis/drug therapy/microbiology/prevention & control ; Diarrhea/diagnosis/microbiology/prevention & control/*veterinary

The worldwide use of antimicrobials in different fields has created enormous pressure for the selection of resistance among opportunistic bacterial pathogen. One hundred four E. coli isolates were collected and identified from swine with diarrhea in Korea during the period of 2002. The isolates showed highly resistant to streptomycin (99. 0%), tetracycline (97. 1%), neomycin (91. 3%)and carbenicillin (84. 6%)in antimicrobial susceptibility test. Moreover, all of the isolates showed multiple antimicrobial resistant to more than 3, and 85%of them were resistant to more than 7 of total 14 antimicrobial agents. In comparison with isolates in 1998, resistance to antimicrobials was more frequent among the isolates in 2002. Presence of class 1 integrons was investigated through amplification of the gene with PCR, and could be classified 8 groups by pattern of 4 different amplicons. Class 1 integrons were observed in 67 strains (64. 2%)of E. coli from swine in Korea. One and 1. 6 kbp of amplicons were revealed to contain aadA1 and aadB-aadA1 gene cassettes respectively. Two kbp of amplicon had three different gene cassettes, dhfrXII-orfF-aadA2, and 3. 0 kbp of amplicon includes aadB-cmlA1 gene cassettes.
Animals ; Anti-Bacterial Agents ; Diarrhea/microbiology/veterinary ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/*drug effects/genetics ; Escherichia coli Infections/microbiology/*veterinary ; Integrons/*genetics ; Swine ; Swine Diseases/*microbiology

The effect of acupuncture in the treatment of young pigs with induced enteropathogenic Escherichia coli diarrhea was histopathologically evaluated by routine hematoxylin and eosin stain. Thirty two pigs weighed 4-5kg and aged 21days old were used in this study. The animals with diarrhea were treated with traditional acupuncture, or enrofloxacin. In the group treated with traditional acupuncture, acupoint GV1 (Jiaochao) was used and in the group treated with antibiotics, enrofloxacin was injected intramuscularly. Ten pigs were inoculated with E. coli, but were not treated and served as nontreated control group. At postinoculation day 6, all pigs of the acupuncture and antibiotic treated groups recovered from diarrhea. In the ascending and descending colons of the nontreated control group, severe infiltration of inflammatory cells in the lamina propria was observed and in the fundic stomach, destruction of the fundic gland architecture and necrotic lesions were observed, however, in the same sites of the acupuncture and antibiotics treated groups, the mucosae of the colon and stomach were relatively similar to those of the normal group. These results indicate that acupuncture treatment is effective in controlling induced E. coli diarrhea in pigs at its early stage.
Acupuncture ; Animals ; Colon/cytology/microbiology/pathology ; Diarrhea/therapy/*veterinary ; Escherichia coli Infections/therapy/*veterinary ; Gastric Mucosa/cytology/microbiology/pathology ; Intestinal Mucosa/cytology/microbiology/pathology ; Male ; Stomach/cytology/microbiology/pathology ; Swine ; Swine Diseases/*microbiology/therapy

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsastained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a coagglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.
Agglutination Tests/methods/*veterinary ; Animals ; *Animals, Newborn ; Antibodies, Monoclonal/*immunology ; Antigens, Surface/immunology/isolation & purification ; Bacterial Toxins/immunology/isolation & purification ; Cattle ; Cattle Diseases/*immunology/*microbiology ; Chromatography, Gel/veterinary ; Chromatography, Ion Exchange/veterinary ; Chromatography, Liquid/veterinary ; Diarrhea/immunology/*veterinary ; Electrophoresis, Polyacrylamide Gel/veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Escherichia coli/*immunology ; Escherichia coli Infections/immunology/*veterinary ; Immunoblotting/veterinary ; Staphylococcus aureus

The prevalence of Lawsonia intracellularis, Brachyspira hyodysenteriae and Salmonella spp. were investigated by multiplex PCR using fecal samples of pigs with diarrhea or a history of diarrhea. The overall herd prevalence of L. intracellularis, B. hyodysenteriae and Salmonella spp. were 46.5%, 37.2% and 51.1%, respectively. Also, the prevalence of L. intracellularis, B. hyodysenteriae and Salmonella spp. among all sampled pigs were 19.9%, 10.8% and 17.7%, respectively. Seventeen of 43 herds were positive with 2 enteric organisms, and 2 herds were positive with L. intracellularis, B. hyodysenteriae and Salmonella spp. simultaneously. It was notable that 11 of 12 herds with more than 2, 000 pigs were affected with Salmonella spp., and that only 2 of 12 the herds were affected with B. hyodysenteriae. This study suggested that herds positive for L. intracellularis, B. hyodysenteriae and Salmonella spp. were distributed throughout Korea, although the relationship among other pathogens such as viral or parasitic ones and/or with metabolic disorders was not determined.
Animals ; DNA, Bacterial/isolation&purification ; Desulfovibrionaceae Infections/epidemiology/microbiology/*veterinary ; Diarrhea/microbiology/veterinary ; Korea/epidemiology ; *Lawsonia Bacteria/isolation&purification ; Polymerase Chain Reaction/veterinary ; Prevalence ; *Salmonella/isolation&purification ; Salmonella Infections, Animal/*epidemiology/microbiology ; *Serpulina hyodysenteriae/isolation&purification ; Spirochaetales Infections/epidemiology/microbiology/*veterinary ; Swine ; Swine Diseases/*epidemiology/microbiology

Enterotoxigenic Escherichia coli (ETEC) causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB (38.9%), estB/STAP (25%), and estB/LT (13.9%) were dominant. Risk factors for ETEC-diarrhea in pigs include: leaving sick piglets in a pen with healthy piglets [odds ratio (OR) = 33.52; P < 0.0001]; water spillage in pen (OR = 42.87; P < 0.0001); hypothermic piglets (OR = 7.29; P < 0.0001); runt piglets in pen with healthy littermates (OR = 3.65; P < 0.0001); and prolonged use of antibiotics (OR = 3.05; P = 0.05).
Animals ; Animals, Newborn ; Diarrhea ; epidemiology ; microbiology ; Escherichia coli ; genetics ; isolation & purification ; Escherichia coli Infections ; epidemiology ; microbiology ; veterinary ; Genes, Bacterial ; Prevalence ; Rectum ; microbiology ; Risk Factors ; South Africa ; Swine ; Swine Diseases ; epidemiology ; microbiology ; Weaning

This study was conducted to determine the prevalence and characteristics of pathogenic Escherichia (E.) coli strains from diarrheic calves in Vietnam. A total of 345 E. coli isolates obtained from 322 diarrheic calves were subjected to PCR and multiplex PCR for detection of the f5, f41, f17, eae, sta, lt, stx1, and stx2 genes. Of the 345 isolates, 108 (31.3%) carried at least one fimbrial gene. Of these 108 isolates, 50 carried genes for Shiga toxin and one possessed genes for both enterotoxin and Shiga toxin. The eae gene was found in 34 isolates (9.8%), 23 of which also carried stx genes. The Shiga toxin genes were detected in 177 isolates (51.3%) and the number of strains that carried stx1, stx2 and stx1/stx2 were 46, 73 and 58, respectively. Among 177 Shiga toxin-producing E. coli isolates, 89 carried the ehxA gene and 87 possessed the saa gene. Further characterization of the stx subtypes showed that among 104 stx1-positive isolates, 58 were the stx1c variant and 46 were the stx1 variant. Of the 131 stx2-positive strains, 48 were stx2, 48 were stx2c, 11 were stx2d, 17 were stx2g, and seven were stx2c/stx2g subtypes. The serogroups most prevalent among the 345 isolates were O15, O20, O103 and O157.
Animals ; Cattle ; Cattle Diseases/epidemiology/*microbiology ; DNA, Bacterial/chemistry/genetics ; Diarrhea/epidemiology/microbiology/*veterinary ; Escherichia coli/genetics/*isolation & purification/pathogenicity ; Escherichia coli Infections/epidemiology/microbiology/*veterinary ; Feces/microbiology ; Fimbriae, Bacterial/genetics ; Polymerase Chain Reaction/veterinary ; Polymorphism, Restriction Fragment Length ; Vietnam/epidemiology ; Virulence Factors/*genetics

Aged ; Animals ; Arcobacter/genetics* ; Chickens ; Diarrhea/microbiology* ; Drug Resistance, Bacterial/genetics* ; Genes, Bacterial ; Gram-Negative Bacterial Infections/veterinary* ; Humans ; Male ; Meat ; Microbial Sensitivity Tests ; Phylogeny ; Poultry Diseases/microbiology* ; Virulence ; Virulence Factors/genetics*