To determine whether an anti-Salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds. 24 Holstein calves experimentally infected and 39 Holstein cows naturally infected with Salmonella spp. An Escherichia coli (designated as P8E5) that possessed anti-Salmonella activity was isolated from Salmonella-negative bovine feces obtained from a herd with endemic Salmonella infection. In vitro analysis involved enumerating Salmonella enterica serovar Typhimurium coincubated with E coli P8E5. In vivo analysis involved coadministration of Salmonella spp and E coli P8E5 or an E coli control strain to neonatal Holstein calves. Fecal samples were collected on multiple days after inoculation, and quantitative PCR assay was performed by use of Salmonella-specific primers. E coli P8E5 reduced viability of Salmonella spp in vitro. Shedding of Salmonella organisms was diminished in calves administered E coli P8E5, whereas the control strain of E coli had no effect on shedding of Salmonella organisms. In this study, an E coli strain was identified that possessed bacteriocin-like activity and was able to decrease viability of Salmonella organisms in vitro and in vivo. Therefore, it is possible that this organism could be representative of native microbiota that dampen Salmonella spp in persistently infected cattle herds.

Consumption of chlortetracycline (CTC) at concentration of 220 mg/kg of feed for 4 weeks in experiment 1 and at concentrations of 110 and 220 mg/kg for 3 weeks and 440 mg/kg for 2 weeks in experiment 2 failed to eliminate streptococci-induced lymphadenitis from swine referred to as principals. Abscesses, mostly in the head and neck, developed in at least a third of all swine in the various groups fed these CTC concentrations. Feeding of 220 mg of CTC/kg of feed in experiment 1 began 12 weeks after exposure of principals to an untypeable group E streptococci (GES; isolate 3X29A). In experiment 2, feeding of 110 and 220 mg of CTC/kg of feed began 5 weeks after exposure of principals to GES and feeding of 440 mg of CTC/kg of feed began 6 weeks after exposure. One or more cohabitating sentinel swine of experiment 1 and one or more sentinels in all groups of principals of experiment 2, except group 2, developed abscesses that were mostly in the head and neck. In experiment 2, correlation between serum GES antibody titer and development of one or more abscesses in the principals was highly significant (P < 0.01); however, correlation between antibody titer and abscesses in the sentinels only approached significance (P < 0.10).

Cows and calves from a 1,600-cow drylot dairy were screened for IgG antibodies to Salmonella dublin lipopolysaccharide (LPS), using an indirect ELISA. The ELISA was performed on milk samples from lactating cows and on sera from nonlactating cows and calves. Fecal samples were collected from calves and nonlactating cows for culture of Salmonella spp. All seropositive cattle were retested by culture and ELISA 5 times at monthly intervals or until antibody concentration decreased. None of the cattle remained culture-positive and seronegative. Prior to and during the sample collection period, approximately 30% of calves < 8 weeks old died of S dublin infection. Vaccination of cows with a killed S dublin/S typhimurium vaccine at cessation of lactation was a routine management practice. The ELISA-determined Igg response to vaccination had decreased by 50 days after vaccination. Eight cows and 5 calves that maintained a high serologic response to S dublin were purchased and moved to a research facility for 6 months of intensive monitoring. Lactating cows were milked twice daily, and culture of milk and feces for Salmonella spp was performed 5 times/wk. Serum IgG antibodies to S dublin LPS were measured weekly, using ELISA. At the end of 6 months, all 13 cattle were necropsied and tissues were obtained for culture of Salmonella spp. All 8 cows and 5 calves maintained persistently high ELISA titer for the 6 months of testing, and shed S dublin in the milk and/or feces during the same period. On this basis, they were termed S dublin carriers. Salmonella dublin was isolated from mammary tissue of 2 calves at necropsy, indicating that bacteremia may be a mode of mammary infection by S dublin. Results of the study indicated serologic testing can be used successfully on a large dairy to identify S dublin carrier cattle. Using initial milk screening, 42 of 1,268 lactating cows were identified as suspect, requiring repeated serologic testing. One nonlactating cow, 7 of the 42 suspect lactating cows, and 5 of the 222 calves maintained an Igg response, and were found to be S dublin carriers. Carrier cows shed S dublin in 3.35% of fecal samples and 2.51% of milk samples, and carrier calves shed S dublin in 17.26% of fecal samples.

The aerobic bacterial flora of the genital tract was characterized in 15 stud dogs in an 18-month study. The dogs represented 4 breeds and were from 3 kennels. Bacterial samples from the prepuce and semen were collected every month, except in connection with matings, when they were collected weekly (464 samples). The dogs that were included all mated at least once during the study. The mean pregnancy rate, litter size, and pup mortality for the bitches with which they had mated were all within normal limits. The most frequent bacteria isolated from the prepuce and semen were Pasteurella multocida, beta-hemolytic streptococci, and Escherichia coli. There was a tendency for breeds to differ in frequency of the most common bacterial species. Bacterial culture yielded no aerobic growth in 14.2% of the preputial samples and 69.8% of the semen samples. Bacteria were transferred between dog and bitch at mating. In this study of healthy breeding dogs, neither the fertility of the dog nor that of the bitch was affected by the bacteria transferred.

Two hundred sixty Haemophilus spp isolates that had been obtained from the respiratory tract and other sites of swine were acquired from diagnostic laboratories, primarily in the United States and Canada. The majority of isolates (243/260) were biochemically characterized as H parasuis; however, a few isolates of taxa distinct from H parasuis (taxa "minor group," D, E, and F) were identified. Fourteen H parasuis serovars were identified, and of those previously described, the most prevalent were 5 (24.3% of isolates), 4 (16.1%), 2 (8.2%), and 7 (3.7%). Three new serovars that were also prevalent included ND4 (11.1%), ND3 (8.6%), and ND5 (6.6%). Serovars 1, 3, 6, C, D, and new serovars ND1 and ND2 were infrequently identified, and 15.2% of isolates were nontypeable. It was not uncommon to isolate multiple serovars from swine of the same herd or related herds. Distribution of serovars among isolates from the United States and Canada was generally similar; however, a higher prevalence of serovar 5 and a lower prevalence of serovars 2, ND3, and ND5 were evident in isolates from Canada. Comparison of isolates obtained from the respiratory tract of swine without polyserositis with those obtained from swine with polyserositis revealed an increased frequency of serovars 4 and 5, and a decreased frequency of serovar 2, among isolates from swine with polyserositis. However, all prevalent serovars were isolated from swine with polyserositis, and data were not indicative of an association between serovar, site of isolation, or pathogenic potential.

The fungal flora of the coat of 172 healthy pet cats was examined qualitatively. Fungi were isolated from 136 (79%) of the 172 cats. Fifteen genera were isolated; 13 are commonly regarded as saprophytes, and 2 (Microsporum and Trichophyton) are commonly regarded as pathogens. Aspergillus, Alternaria, Penicillium, and Cladosporium spp were the most frequently isolated saprophytes. Dermatophytic fungi, including Microsporum gypseum (n = 1), M vanbreuseghemii (n = 1), and Trichophyton rubrum (n = 14), were recovered from 16 cats. Microsporum canis was not isolated from any cat during this study.

Healthy conjunctival sacs of 88 animals of 3 species of captive camelids (Lama glama, Lama guanicoe, Lama pacos) and llama-guanaco hybrids were sampled for bacterial and mycoplasmal flora. Mycoplasmas were not isolated from any animal. Eleven genera of bacteria were isolated. The most frequent isolates were Staphyloccus epidermidis and Pseudomonas spp. Nine varieties of Pseudomonas were found, which represented at least 3 Pseudomonas species. Many of the bacterial isolates (especially the pseudomonads) are potential pathogens in the eyes of these camelids.

An ELISA has been developed for measurement of milk and serum IgG concentrations directed against Salmonella dublin. Four groups of cows were studied: group A-7 experimentally challenge-exposed cows (infected, recovered group); group B-6 normal uninfected randomly selected control cows; group C-7 naturally occurring S dublin carrier cows; and group D-6 normal uninfected S dublin negative cows from the same herd as group C. Group-A cows were inoculated orally, or inoculated orally and then IV, but none became a S dublin carrier. As expected, all 7 group-A cows responded with a marked increase in ELISA titer after oral exposure to virulent S dublin, starting with a mean serum titer of 17.7% and reaching a peak mean serum titer of 79.3% approximately 76 days after initial exposure. As determined by necropsy and organ culturing of the remaining cows, none of the group-A cows became carriers. The mean serum ELISA titer for group-B uninfected control cows was 14.1% (SD +/- 12.8%). The mean milk ELISA titer was -1.0% (SD +/- 5.5%). Colostrum and then milk gave false-positive results for up to 2 weeks after onset of lactation. Group-B cows were culture negative for S dublin in feces and milk during lactation, and when tissues were cultured after euthanasia. Milk and serum samples for ELISA, and milk and fecal samples for culturing were taken from all group-A and -B cows twice a week for 6 months. Statistical correlation (P less than 0.05) was found between serum and milk ELISA titers. A highly significant (P less than 0.001) difference in serum ELISA titers was demonstrated between control (group B) and infected cows (group A). Milk and feces from group-C carrier cows were cultured for S dublin 5 days a week for 11 to 13 months. Six of the 7 cows calved during this period. Fecal shedding was sporadic in 7 cows. Milk shedding was frequent in certain quarters of 4 of the cows and was sporadic or absent in other quarters of these cows and it was sporadic in 2 cows, and 1 cow had culture-positive milk only twice. The overall milk-shedding rate was 46% (792 positives/1,733 samples), whereas the overall fecal-shedding rate was 4% (65 positives/1,733 samples). Shedding in the 4 weeks after parturition was 28% in milk and 5% in feces. Six group-C cows had strongly positive ELISA titers in serum and milk, whereas 1 cow (the cow that had only 2 positive milk cultures) had relatively low ELISA titers. Group-C cows had a mean serum titer of 85.2% (SD +/- 19%) and mean milk titer of 70.6% (SD +/- 35.5%). These results indicate that IgG ELISA may be useful in detection of S dublin milk shedding (mammary gland infection) carrier cows. Milk shedding in the 4 persistent shedders ranged from 10(1) to 10(5) organisms/ml, and was associated with evidence of chronic active mastitis. Group-D cows, culture-negative herd mates of group-C carrier cows, were monitored in a manner identical to that used for group-C cows. All cows remained culture-negative for S dublin in feces and milk and results of organ culturing were negative for S dublin after euthanasia. The ELISA titers remained negative, with a mean group-D titer of 8 +/- 7.7% on serum, and 0.6 +/- 5.5% on milk. A highly significant difference in serum (P less than 0.0001) and milk (P less than 0.0001) ELISA titers was demonstrated between group-C carrier cows and group-D uninfected herd mates.

To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot. 21,743 high-risk calves from the southeastern United States. PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase-PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot. 15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal. This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.

Pathogens causing significant respiratory disease in growing pigs include Porcine reproductive and respiratory syndrome virus, Porcine circovirus 2, swine influenza virus, porcine respiratory coronavirus, Mycoplasma hyopneumoniae, and Bordetella bronchiseptica. The objective of this research was to characterize the respiratory excretion of these pathogens by acutely infected pigs. Pigs were inoculated under experimental conditions with 1 pathogen. Samples were collected from the upper respiratory tract and exhaled air. All pathogens were detected in swabs of the upper respiratory tract, but only M. hyopneumoniae and B. bronchiseptica were detected in expired air from individually sampled, acutely infected pigs. These findings suggest either that the acutely infected pigs did not aerosolize the viruses or that the quantity of virus excreted was below the detection threshold of current sampling or assay systems, or both, at the individual-pig level.