Investigation of bovine brucellosis in the Northeastern Turkey

Bovine brucellosis, caused by Brucella abortus, is a significant problem for both public and animal health in Turkey. This study was conducted on the calving seasons between 2001 and 2006. A total of 626 serum samples of cattle obtained from 27 herds with a history of abortions was examined for Brucella antibodies by RBPT, SAT and ELISA. Of the cattle sera analysed, 221 (35,30%) and 206 (32, 92%) and 247 (39,45%) were found to be positive by RBPT , SAT and ELISA, respectively. B. abortus was isolated from 48 (32,21%) of 149 lung samples and stomach contents of the aborted fetuses. Based on the biochemical tests and the agglutination tests with monospecific A and M antisera, only 3 of the isolates were found to be B. abortus biotype 1 and the remaining 45 were biotype 3. This study also revealed that the dominant biotype of B. abortus was biotype 3 in this region. The determination of the agents responsible for bovine brucellosis and serosurvey of this disease are expected to help better understanding of this zoonotic infection in this region and neighbouring countries.     

Live Brucella abortus rough vaccine strain RB51 stimulates enhanced innate immune response in vitro compared to rough vaccine strain RB51SOD and virulent smooth strain 2308 in murine bone marrow-derived dendritic cells

Brucella spp. are Gram-negative, coccobacillary, facultative intracellular pathogens. B. abortus strain 2308 is a pathogenic strain affecting cattle and humans. Rough B. abortus strain RB51, which lacks the O-side chain of lipopolysaccharide (LPS), is the live attenuated USDA approved vaccine for cattle in the United States. Strain RB51SOD, which overexpresses Cu–Zn superoxide dismutase (SOD), has been shown to confer better protection than strain RB51 in a murine model. Protection against brucellosis is mediated by a strong CD4+ Th₁ and CD8+ Tc₁ adaptive immune response. In order to stimulate a robust adaptive response, a solid innate immune response, including that mediated by dendritic cells, is essential. As dendritic cells (DCs) are highly susceptible to Brucella infection, it is possible that pathogenic strains could limit the innate and thereby adaptive immune response. By contrast, vaccine strains could limit or bolster the innate and subsequent adaptive immune response. Identifying how Brucella vaccines stimulate innate and adaptive immunity is critical for enhancing vaccine efficacy. The ability of rough vaccine strains RB51 and RB51SOD to stimulate DC function has not been characterized. We report that live rough vaccine strain RB51 induced significantly better (p ≤ 0.05) DC maturation and function compared to either strain RB51SOD or smooth virulent strain 2308, based on costimulatory marker expression and cytokine production.     

Brucella abortus is Prevalent in Both Humans and Animals in Bangladesh

To determine the role of different Brucella (B.) spp. in Bangladesh, 62 animal samples and 500 human sera were tested. Animal samples from cattle, goats and sheep (including milk, bull semen, vaginal swabs and placentas) were cultured for Brucella spp. Three test‐positive human sera and all animal samples were screened by Brucella genus‐specific real‐time PCR (RT‐PCR), and positive samples were then tested by IS711 RT‐PCR to detect B. abortus and B. melitensis DNA. Only B. abortus DNA was amplified from 13 human and six animal samples. This is the first report describing B. abortus as the aetiological agent of brucellosis in occupationally exposed humans in Bangladesh. Of note is failure to detect B. melitensis DNA, the species most often associated with human brucellosis worldwide. Further studies are required to explore the occurrence of Brucella melitensis in Bangladesh.     

Antimicrobial resistant Escherichia coli isolates in cattle and house sparrows on two Czech dairy farms

Rectal smears of calves, cows and young bulls, as well as cloacal smears of house sparrows (Passer domesticus), from farms at the villages of Šumice and Troskotovice, Czech Republic, were examined for E. coli resistant to 12 antimicrobials. The resistant isolates were tested for antimicrobial-resistance genes and integrons. Totals of 40% (n = 183), 3% (n = 95), 0% (n = 33), and 9% (n = 54) of Escherichia coli isolates from calves, cows, young bulls and house sparrows, respectively, were antimicrobial resistant. The following genes were identified in cattle E. coli isolates: tetA, tetB (isolates resistant to tetracycline), bla_TEM (beta-lactams), strA, aadA (streptomycin), sul1, sul2 (sulphonamides), and cat, floR (chloramphenicol). Seven of 16 antimicrobial-resistant calf isolates from the Šumice farm possessed class 1 integrons with the aadA1 gene cassette integrated, 1 kb in size. On the Troskotovice farm, eight of 57 antimicrobial-resistant calf isolates possessed class 1 integrons. Integrons of 1.5 kb with the dhfr1- aadA1 gene cassette were found in four isolates, followed by a 1 kb integron with the aadA1 gene found in three isolates, and a 1.7 kb integron with the dhfr17-aadA5 gene cassette and the phenotype ASSuTSxtNaCipCCfG. The prevalence of resistant E. coli in calves compared to adult cattle was much higher and probably was influenced by oral antimicrobial usage in calves, feeding with milk and colostrum from treated cows, as well as mechanisms unrelated to antimicrobial drug selection. Although house sparrows lived together with the cattle and came into contact with cattle waste on the farm, they were not infected by resistant E. coli isolates with the same characteristics as those found in cattle.     

Molecular biological identification of Babesia,Theileria, and Anaplasma species in cattle in Egypt using PCR assays,gene sequence analysis and a novel DNA microarray

In this preliminary study, a novel DNA microarray system was tested for the diagnosis of bovine piroplasmosis and anaplasmosis in comparison with microscopy and PCR assay results. In the Dakahlia Governorate, Egypt, 164 cattle were investigated for the presence of piroplasms and Anaplasma species. All investigated cattle were clinically examined. Blood samples were screened for the presence of blood parasites using microscopy and PCR assays. Seventy-one animals were acutely ill, whereas 93 were apparently healthy. In acutely ill cattle, Babesia/Theileria species (n = 11) and Anaplasma marginale (n = 10) were detected. Mixed infections with Babesia/Theileria spp. and A. marginale were present in two further cases. A. marginale infections were also detected in apparently healthy subjects (n = 23). The results of PCR assays were confirmed by DNA sequencing. All samples that were positive by PCR for Babesia/Theileria spp. gave also positive results in the microarray analysis. The microarray chips identified Babesia bovis (n = 12) and Babesia bigemina (n = 2). Cattle with babesiosis were likely to have hemoglobinuria and nervous signs when compared to those with anaplasmosis that frequently had bloody feces. We conclude that clinical examination in combination with microscopy are still very useful in diagnosing acute cases of babesiosis and anaplasmosis, but a combination of molecular biological diagnostic assays will detect even asymptomatic carriers. In perspective, parallel detection of Babesia/Theileria spp. and A. marginale infections using a single microarray system will be a valuable improvement.     

Ivermectin and moxidectin resistance characterization by larval migration inhibition test in field isolates of Cooperia spp. in beef cattle,Mato Grosso do Sul,Brazil

Ivermectin (IVM) resistance of Cooperia spp. in cattle has become an increasing and global problem. The early detection of anthelmintic resistance (AR) is important to propose strategies to slow down the development of resistance and requires sensitive, reliable, economic high-throughput and practical tests. The purpose of the present study was to apply a larval migration inhibition test (LMIT) for evaluating IVM and MOX efficacy against well-characterized field isolates of Cooperia spp. infecting cattle in Brazil. Eight isolates were used for IVM and seven for MOX. The following EC50 values of IVM were observed for the isolates: susceptible, 1.16 ηmol; Nova Alvorada do Sul I, 4.09 ηmol (RF = 3.52); Campo Grande BNA, 3.57 ηmol (RF = 3.07); Campo Grande TBR, 4.09 ηmol (RF = 3,52); Nova Alvorada do Sul II, 2.50 ηmol (RF = 2.15); Bandeirantes, 11.35 ηmol (RF = 9.78); Campo Grande II, 6.03 ηmol (RF = 5.20); and Porto Mortinho, 8.63 ηmol (RF = 7.44). For MOX, the following EC50 values were observed: susceptible, 0.75 ηmol; Campo Grande BNA, 0.93 ηmol (RF = 1.24); Campo Grande TBR, 0.36 ηmol (RF = 0.48); Nova Alvorada do Sul II, 2.57 ηmol (RF = 3.42); Bandeirantes, 1.43 ηmol (RF = 1.90); Campo Grande II, 1.08 ηmol (RF = 1.44); and Porto Mortinho, 0.49 ηmol (RF = 0.65). The LMIT used in the present study can be a useful tool for in vitro evaluation of IVM, but not of MOX. However, such methodology cannot be used in large-scale studies yet. The isolates of Cooperia spp. showed various degrees of resistance to IVM, though remaining susceptible to MOX.     

Brucellosis in migratory sheep flock from Maharashtra,India

Brucellosis is a zoonotic disease worldwide distributed and having the economic as well as public health importance. The prevalence of brucellosis among sheep flock having history of abortions was studied. A total of 229 samples comprising of 157 blood and 72 clinical samples (vaginal swabs) were collected from 157 animals. Clinical samples were processed for the isolation of Brucella melitensis. Serum samples (n = 157) were tested by Rose Bengal plate test (RBPT) and i-ELISA. A total of 68 (43.31%) and 104 (66.24%) samples were positive by RBPT and ELISA, respectively. Brucella isolates (n = 2) were recovered from clinical samples. Both isolates demonstrated amplification for bcsp 31 and IS711 genes. On AMOS PCR, both the isolates amplified at 731 bp, i.e., belongs to B. melitensis species. The incidence of B. melitensis in a migratory flock warns the thorough testing and culling of Brucella-infected sheep from the flock on a continuous basis; otherwise, such incidence will be routine and poor farmers will be at a loss.     

Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain

The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors.In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR = 3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR = 3), the youngest bovines (<2.5 years) and dairy cattle (Friesians).Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5–7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years.It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.     

Frequency of virulence factors in Escherichia coli isolated from suckling pigs with diarrhoea in China

Escherichia coli-associated diarrhoea is an important disease adversely affecting the pig industry. This study was conducted to investigate the frequency of virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China. A total of 381 E. coli strains, obtained from 290 faecal samples from pigs on 38 farms, were tested for fimbriae (K88, K99, 987P, F41, F18, F17), non-fimbrial adhesins (AIDA-I, paa, CS31A, eae, saa), enterotoxin (LT-I, LT-II, STa, STb, EAST1), Shiga toxin (Stx1, Stx2, Stx2e), pathogenicity islands (HPI, LEE), α-haemolysin (hlyA), afa8 gene cluster (afaD, afaE) and sepA genes by PCR. Out of the 381 isolates, 206 carried at least one virulence gene. Of the 206 virulence positive isolates, the virulence factor genes detected were EAST1 (n = 120), irp2 (n = 59), paa (n = 50), STb (n = 41), AIDA-I (n = 34), LT-I (n = 23), ler (n = 11), hlyA (n = 9), K88 (n = 8), eae (n = 8), STa (n = 7), sepA (n = 6), F18 (n = 5), afaD (n = 3), afaE (n = 3), K99 (n = 2) and Stx2e (n = 1), with most isolates carrying multiple virulence genes. These results demonstrate that relatively few isolates from the study population express K88, K99, LT-I or STa, but that EAST1 (58%), irp2 (29%), AIDA-I (16.5%), paa (24%) and STb (20%) are frequent virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China.     

Genetic analysis of multi-drug resistance and the clonal dissemination of β-lactam resistance in Salmonella Infantis isolated from broilers

An epidemiologic study was conducted to investigate the incidence and characterize the antimicrobial resistance determinants, analyzing plasmid profiles, and establishing the genetic relationship among β-lactam-resistant isolates of Salmonella Infantis from broilers in Southern Japan. A total of 120 isolates were recovered from 56 flocks belonging to 44 holdings during 2004–2006. The percentages of resistance were as follows: ampicillin (24%), cephalothin (23%), cefoxitin (0%), ceftazidime (11%), cefotaxime (11%), chloramphenicol (0%), kanamycin (7.5%), ofloxacin (20%), oxytetracycline, streptomycin and sulfamethoxazole (100%) and trimethoprim (75%). The incidence of bla_TEM-encoded β-lactam resistance in 2004–2006 was significantly higher than in 1998–2003 (P < 0.001). BlnI-digested PFGE patterns generated two related clusters implicated in the dissemination of β-lactam resistance. Two types of plasmid profiles were observed and two plasmids of ca. 50 and 180-kb size were carried by β-lactam-resistant isolates. Streptomycin resistance was conferred by aadA1 (n = 116), aadA1-aadA2 (n = 1), and aadA1-strA-strB (n = 3). Resistances to kanamycin, oxytetracycline, sulfamethoxazole and trimethoprim were conferred by aphA1 (n = 9, 100%), tetA (n = 120, 100%) sul1 (n = 120, 100%) and dfrA5 (n = 90, 100%), respectively. Two types of class 1 integrons were detected: 1.0 kb (n = 120) and, 1.0/1.5 kb (n = 3). Integrons of 1.0/1.5 kb were found in isolates with the aadA1-strA-strB gene combination. For the first time, all S. Infantis isolates showed resistance to at least three classes of antimicrobial agents; and the intestinal tract of healthy poultry was a reservoir of the extended-spectrum cephalosporin-resistant isolates of serovar Infantis.     

NTPDase and 5′-nucleotidase as inflammatory markers in cattle naturally infected by Eurytrema coelomaticum

The aim of this study was to evaluate seric NTPDase and 5′nucleotidase activities of cattle naturally infected by Eurytrema coelomanticum, as well as to correlate them to histopathological lesions in the pancreas and the degree of parasitism. Blood samples and pancreas of 51 bovines were collected on a slaughterhouse in Southern Brazil: 33 from cattle naturally infected by E. coelomanticum (the Group A), and 18 from uninfected animals (the Group B). Infected animals showed an average of 532 parasites per pancreas. In the pancreatic histology, ducts displayed hyperplasia, stenosis, proliferation of fibrous tissue, and interstitial inflammatory infiltration of lymphocytes. The serum from infected animals showed an increase in NTPDase activity when ATP was used as substrate (P < 0.001). For the ADP substrate, there was no difference between groups regarding NTPDase activity (P = 0.37), as well as 5′-nucleotidase activity (P = 0.27). Correlating NTPDase activity (ATP substrate) with the degree of histopathological lesions (rho = 0.66, P < 0.001) and the parasitic load on the pancreas (rho = 0.65, P < 0.001), a positive correlation was observed. Similar results were found between the degree of histopathological lesions and NTPDase activity (ADP substrate; rho = 0.29, P = 0.03), and 5′nucleotidase activity (rho = 0.35, P = 0.01). Based on the results of NTPDase and 5′nucleotidase enzymes in cattle naturally infected by E. coleomanticum, it is possible to suggest that these enzymes are involved in the modulation of inflammation, and they can act as markers of inflammatory response.     

Isolation and identification of bovine Brucella isolates from Pakistan by biochemical tests and PCR

Brucellosis is endemic in bovines in Pakistan. The Brucella species and biovars involved, however, are unknown. The objectives of the present study were to isolate and characterize brucellae from seropositive milk samples, aborted fetuses, and vaginal swabs of cattle and buffaloes which had recently aborted. The seropositive milk samples, aborted fetuses, and vaginal swabs of cattle and buffaloes were collected from the Potohar Plateau, Pakistan. Isolation of brucellae was done on modified Farrell’s serum dextrose agar. Isolates were characterized by conventional biotyping methods, while molecular typing was done by genus (B4/B5) and species-specific (Brucella abortus, Brucella melitensis, Brucella ovis, and Brucella suis) polymerase chain reaction (PCR). A total of 30 isolates were recovered from milk (n?=?5), aborted fetuses (n?=?13), and vaginal swabs (n?=?12). Most isolates were from cattle (56.7 %). All of them were identified as B. abortus biovar 1 based on conventional biotyping methods and genus and species-specific PCR. This preliminary study provides the first report on the prevalence of B. abortus biovar 1 in cattle and buffaloes in Pakistan.     

Entamoeba infections in different populations of dogs in an endemic area of Lahore,Pakistan

Entamoeba histolytica, a protozoan parasite that affects humans and other primates all over the world. It is a common waterborne pathogen in endemic areas that have fecal oral transmission cycle. The aim of the present study was to examine the prevalence of E. histolytica and other Entamoeba species cysts in three different dog populations. Fecal samples from 600 dogs were collected and processed to detect Entamoeba cysts using the triple fecal test (light microscopy) and fecal antigens of E. histolytica were detected using a fecal antigen ELISA (TechLab E. histolytica II). Because it is impossible to differentiate E. histolytica from Entamoeba dispar and E. moshkovskii, using light microscopy we referred to all cysts morphologically consistent with E. histolytica as E. histolytica/dispar/moskovskii to reflect this uncertainty. Samples from 197 household dogs without clinical signs, 122 samples from household dogs exhibiting clinical signs of diarrhea, dysentery and vomiting and 281 stray dogs with no specific clinical signs were examined. Entamoeba histolytica-like cysts were observed in 94 (15.6%, 95% CI = ±3.88) by triple fecal test microscopy and E. histolytica antigens were demonstrated in 66 (11%, 95% CI = ±4.41) by fecal antigen ELISA in 600 fecal samples. Significant differences (P ≤ 0.05) in prevalence were found between the three populations. Twenty (10.1%, 95% CI = ±7.86) and 11 (5.6%, 95% CI = ±7.70) of 197 fecal samples from household dogs without clinical signs were positive by microscopy and by antigen ELISA, respectively. Twenty-nine (23.8%, 95% CI = ±6.58) and 23 (18.8%, 95% CI = ±7.81) of 122 the fecal samples from household dogs with clinical signs were positive by microscopy and by antigen ELISA, respectively. Forty-five (16.01%, 95% CI = ±5.62) and 32 (11.3%, 95% CI = ±6.38) of 281 fecal samples from stray dogs were positive by microscopy and by fecal antigen ELISA, respectively. Dogs from the youngest age group (6 months to 1 year) were more likely to be E. histolytica antigen positive than were dogs from the other two older age groups, with a significant difference (P ≤ 0.05) between all age groups. Statistically, no significant (P ≥ 0.05) difference of prevalence was seen in male and female dogs. The local dogs had the highest prevalence rate of E. histolytica antigens (36 of 246, 14.2%, 95% CI = ±6.32) followed by imported breeds (11 of 115, 9.5%, 95% CI = ±10.4) and crossbred (19 of 239, 8.3%, 95% CI = ±7.47), indicating a significant (P ≤ 0.05) trend of positivity between various breeds of dogs. These findings suggest that dogs may play an important role in the epidemiology of this pathogen.     

Outbreak of anaplasmosis associated with novel genetic variants of Anaplasma marginale in a dairy cattle

During early lactation, dairy cows may present a transient immunosuppressive state and develop anaplasmosis caused by Anaplasma marginale. In this study, clinical anaplasmosis in dairy cattle in the Thrace region of Turkey was investigated with respect to within-herd prevalence, vertical transmission, and genetic diversity. In March and September 2015, thirty lactating cows showed primary clinical signs of anaplasmosis, including fever, anaemia, decreased milk yield, anorexia, and laboured breathing. Symptoms disappeared in most cows after administration of long-acting oxytetracycline, but nine of them (30%) died. Following diagnosis based on clinical signs, microscopy and molecular findings, blood samples were collected from apparently healthy lactating cows (n = 184), pregnant heifers (n = 39) and newborn calves (n = 24). DNA was extracted from each sample and analyzed for the presence of major surface proteins (MSPs) of A. marginale, followed by sequencing to assess diversity of isolates. Microscopic examination of erythrocytes revealed A. marginale inclusion bodies in symptomatic cows. Examination of thin blood smears showed 3.8% of the lactating, clinically asymptomatic, cows to be infected with A. marginale, while nPCR detected 31.0% positive. A. marginale infection was not detected in pregnant heifers by either method. Congenital infection was found in one calf by nPCR. This is the first report of transplacental transmission of A. marginale in Turkey. The MSP4 sequence analyses showed high genetic diversity among the isolates, presenting 97.6-99.6% homology at the amino acid level. The sequences of MSP1a amplicons revealed genetic diversity providing three new tandem repeats.     

Stocking Rate and Fuels Reduction Effects on Beef Cattle Diet Composition and Quality

An experiment was conducted to evaluate the influence of forest fuels reduction on diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with whole plots (3 ha) being fuel reduced or no treatment (control), and split plots (1 ha) within whole plots were grazed to three levels of forage utilization; (low) 3 heifers · ha^?1, (moderate) 6 heifers · ha^?1, (high) 9 heifers · ha^?1, with a 48-h grazing duration. Grazing treatments were applied in August of 2005 and 2006. Cattle diet composition and masticate samples were collected during 20-min grazing bouts using six ruminally cannulated cows in each experimental unit. Relative preference indices indicated a strong preference for grass regardless of treatment and stocking rate. Grass consumption was lower in control pastures (P < 0.05) and tended (P < 0.095) to decrease with increased stocking rates. Shrub use was higher in control pastures displaying a quadratic effect (P < 0.05) due to stocking, whereas shrub use increased with stocking rate across all treatments. Cattle grazing control pastures consumed diets higher in crude protein compared to cattle grazing treated pastures (P < 0.05). In vitro dry matter digestibility values were lower (P < 0.05) in control sites and tended (P = 0.10) to decrease with increased stocking rates. In both control and treated pastures, bites per minute and grams consumed per minute declined (P = 0.003) with increased stocking, indicating foraging efficiency of cattle decreases with increased stocking rates. Our data indicated cattle grazing late season grand fir habitat types have a strong preference for grasses regardless of treatment or stocking rate. However, as stocking rate increased in both control and treated pastures, grass consumption decreased, shrub consumption increased, and foraging efficiency decreased.     

High occurrence of multi-antimicrobial resistance in Staphylococcus intermedius isolates from healthy and diseased dogs and domesticated pigeons

Staphylococcus intermedius isolates (n = 106), including 44 dog isolates and 62 pigeon isolates, were examined for their susceptibility to ampicillin, cephalexin, erythromycin, gentamicin, kanamycin, lincomycin, norfloxacin, oxacillin, tetracycline, and vancomycin by standard disk-diffusion test. The frequencies of resistance to ampicillin, kanamycin, and tetracycline were significantly higher in dog isolates than pigeon isolates (95.5% vs. 0%, 31.8% vs. 0%, and 45.5% vs. 9.7%, respectively; P < 0.01). Antimicrobial resistance patterns of dog isolates and pigeon isolates were categorized respectively into nine and five distinct profiles. Significantly higher occurrence of resistance to two or more antimicrobials was observed in dog isolates than pigeon isolates (54.5% vs. 12.9%; P < 0.01) and also in domesticated pigeon isolates than non-domesticated pigeon isolates (53.3% vs. 0%; P < 0.01).     

Risk factors associated with Neospora caninum seropositivity in randomly sampled Canadian dairy cows and herds

Our objective was to determine cow- and herd-level risk factors associated with seropositivity for Neospora caninum in a large number of randomly selected Canadian dairy herds, controlling for important confounding variables and co-infections with bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV) and Mycobacterium avium subspecies paratuberculosis (MAP). Serum samples were obtained from 30 randomly selected cows, where available, in 240 herds using monthly milk testing, within 6 of 10 provinces, and these samples were tested for antibodies against BLV, MAP and N. caninum using commercially available ELISA test kits. Five unvaccinated cattle >6 months old from each herd were tested for antibodies to BVDV using virus neutralization. Most herd-level predictors were obtained through personal interviews with questionnaires administrated to each farm manager. A mixed logistic-regression model was built using N. caninum serostatus at the cow-level as the outcome variable, with herd as a random effect and province as a fixed effect. A BLV seropositive cow was 1.50 times more likely to be seropositive for N. caninum than a BLV-seronegative cow, and this was the only cow-level variable to remain in the final model. Regarding herd-level variables, with “no on-farm dogs” as the baseline, “presence of dogs but not known to eat placentas and/or fetuses” increased the odds of seropositivity for N. caninum by a factor of 1.66. For “presence of dogs known to eat placentas and/or fetuses”, the odds ratio (OR) was 2.75, demonstrating a dose–response relationship. “Using embryo transfer” (OR = 0.69), “asking for a BVDV-negative test before introducing an animal” (OR = 0.30), “using monensin in dry cows” (OR = 0.71), and “heifers having nose-to-nose contact with calves” (OR = 0.73) were all dichotomous variables negatively associated with seropositivity for N. caninum. “Number of milk cows on the farm” (OR = 0.99), and “area (acres) used for forage production” (OR = 0.99) were continuous variables negatively associated with N. caninum seropositivity.     

Transmission dynamics of Mannheimia haemolytica in newly-received beef bulls at fattening operations

The primary objective of this study was to determine, at the lung level, whether single or multiple clones of Mannheimia haemolytica are present within a pen during a bovine respiratory disease (BRD) episode. A secondary objective was to assess whether M. haemolytica isolates obtained from nasal swabs (NS) are identical to those isolated deeper within the respiratory tract. Sixteen BRD episodes that naturally occurred in 12 pens of eight to 12 bulls (n = 112) newly-received at three fattening operations were investigated. One hundred and seventy five M. haemolytica isolates were collected from 239 pairs of trans-tracheal aspirations (TTA) and NS performed during these 16 BRD episodes. M. haemolytica isolates were characterized by pulsed-field gel electrophoresis (PFGE). PFGE types obtained from NS and TTA were then compared. M. haemolytica was isolated during 14 BRD episodes. Two to three different clones of M. haemolytica were recovered during 10 episodes whereas only one clone was recovered in four episodes. A moderate agreement (kappa = 0.50) between NS and TTA for M. haemolytica isolation was observed. Identical PFGE types were only observed in 77% of matched NS-TTA pairs. The significant within-pen diversity of M. haemolytica during BRD episodes indicates that the disease is not primarily due to the spread of a single virulent clone among cattle and highlights the importance of predisposing factors that enable the resident flora to overcome the cattle's immune system. The results also demonstrate that isolates recovered from NS are not always representative of the isolates present deeper within the respiratory tract.     

Outbreak of Brucellosis in Domestic Elk in Korea

Seven of 18 elk on a deer farm were found by the official Rose‐Bengal agglutination test (RBT) and tube agglutination test to be brucellosis reactors/suspects. Evaluation with the competitive ELISA (C‐ELISA) and the fluorescence polarization assay (FPA) tests revealed that six and five sera were positive respectively. The seven reactors/ suspects were slaughtered and their blood and tissues were collected. Brucella species could be isolated from three of the slaughtered animals, with nine isolates being obtained from the popliteal, supramammary and submandibular lymph nodes, vaginal discharge, mammary tissue and spleen. Brucella genus‐specific PCR based on 16S rRNA and AMOS‐PCR, which is specific for differential Brucella species, revealed that all nine isolates were Brucella abortus. These nine were further confirmed to be B. abortus biovar 1 by classical biotyping scheme assays. This is the first report of an outbreak of brucellosis in domestic elk in Korea. Our observations suggest that deer should be included in the routine Brucella surveillance programme for the effective control and prevention of brucellosis in Korea.