Experimental infection of Artibeus intermedius with a vampire bat rabies virus

Experimental infection of Artibeus intermedius, the great fruit-eating bat, was performed with vampire bat rabies isolates. Bats (n = 35) were captured in the wild and quarantined prior to experimental infection. No rabies antibodies were detected by rapid fluorescent focus inhibition test (RFFIT) prior to infection. Three doses of rabies virus (RV) and three different routes of infection were used. One out of 35 bats died without showing any clinical signs at day 14 and was positive for rabies. None of the 34 other bats showed clinical signs for rabies, but high antibody titers were detected post-inoculation, suggesting either innate immune response to the vampire bat rabies virus or possible pre-exposure to RV and inoculation leading to a booster effect. Rabies virus was detected by hemi-nested RT-PCR (hnRT-PCR) in the brain (n = 3), stomach (n = 1) of bats that were negative by immunofluorescence and that survived rabies infection. The bat that died on day 14 was positive by hnRT-PCR on the brain, heart and liver. These results suggest that either previous non-lethal exposure to RV or natural low susceptibility to vampire bat viruses somehow protected Artibeus intermedius from clinical rabies infection leading to a marginal lethality effect on this bats species population in the wild.     

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.     

Cattle Grazing Distribution and Efficacy of Strategic Mineral Mix Placement in Tropical Brazilian Pastures

A study was conducted in Brazil to identify factors affecting grazing distribution of yearling Nelore cross heifers and to evaluate the efficacy of placement of a salt–mineral mix away from water to improve uniformity of grazing. Two pastures (25 ha and 42 ha) were evaluated for four 15-d sessions. Mineral mix was placed 590 m to 780 m from water during two sessions and at water for two sessions. Stubble heights were measured at the beginning and end of each session in 1-ha subunits of each pasture. Cattle locations were recorded on day 13 and 14 of each session by horseback observers. Heifers avoided areas with a preponderance of forbs and taller grass (P < 0.001). For the first 15 days of the study cattle avoided subunits farther from water. Thereafter, horizontal distance from water had no affect on grazing use (P > 0.10). Stubble height reduction was more uniform (P < 0.05) when the mineral mix was at water compared to away from water. In contrast, heifers spent less time farther from water when mineral mix was placed at water (P = 0.02) based on visual observations. Strategic placement of a salt–mineral mix away from water does not appear to be a reliable tool to improve cattle grazing distribution in humid tropical pastures from 25 ha to 45 ha in size.     

Susceptibility of Rhipicephalus (Boophilus) microplus to ivermectin (200, 500 and 630 μg/kg) in field studies in Brazil

The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 μg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5–8.0 mm long) counted on three consecutive days (−3, −2 and −1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 μg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 μg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 μg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.     

Evaluation of Low-Stress Herding and Supplement Placement for Managing Cattle Grazing in Riparian and Upland Areas

Management practices are often needed to ensure that riparian areas are not heavily grazed by livestock. A study was conducted in Montana during midsummer to evaluate the efficacy of low-stress herding and supplement placement to manage cattle grazing in riparian areas. Three treatments were evaluated in three pastures over a 3-yr period in a Latin-square design (n = 9). Each year, naïve 2-yr-old cows with calves were randomly assigned to the three treatments: 1) free-roaming control, 2) herding from perennial streams to upland target areas, and 3) herding to upland sites with low-moisture block supplements. Stubble heights along the focal stream were higher (P = 0.07) in pastures when cattle were herded (mean ± SE, 23 ± 2 cm) than in controls (15 ± 3 cm). Global positioning system telemetry data showed that herding reduced the time cows spent near (< 100 m) perennial streams (P = 0.01) and increased the use of higher elevations (P = 0.07) compared with controls. Evening visual observations provided some evidence that free-roaming cows (44% ± 19%) were in riparian areas more frequently (P = 0.11) than herded cows (23% ± 6%). Fecal abundance along the focal stream was less (P = 0.07) with herding (61.9 ±  kg · ha⁻¹) than in controls (113.2 ±  kg · ha⁻¹). Forage utilization within 600 m of supplement sites was greater (P = 0.06) when cows were herded to low-moisture blocks (18% ± 6%) compared with controls and herding alone (8% ± 2%). Moving cattle to uplands at midday using low-stress herding is an effective tool to reduce use of riparian areas. Herding cattle to low-moisture blocks can increase grazing of nearby upland forage but may not provide additional reduction in cattle use of riparian areas compared with herding alone.     

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.     

Molecular epidemiological analysis of bat rabies viruses in Brazil

A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. The first lineage consisted mainly of haematophagous bat (Desmodus rotundus) isolates, including frugivorous bat (Artibeus spp.) isolates. Other three lineages consisted of insectivorous bat isolates; mainly Eptesicus spp., Molossus spp. and Nyctinomops spp. isolates, respectively. These results indicate a possibility of that there are bat species-specific RV variants in Brazil.     

Spatial Redistribution of Nitrogen by Cattle in Semiarid Rangeland

Nitrogen (N) availability can strongly influence forage quality and the capacity for semiarid rangelands to respond to increasing atmospheric CO₂. Although many pathways of nitrogen input and loss from rangelands have been carefully quantified, cattle-mediated N losses are often poorly understood. We used measurements of cattle N consumption rate, weight gains, and spatial distribution in shortgrass rangeland of northeastern Colorado to evaluate the influence of cattle on rangeland N balance. Specifically, we estimated annual rates of N loss via cattle weight gains and spatial redistribution of N into pasture corners and areas near water tanks, and used previous studies to calculate ammonia volatilization from urine patches. Using measurements of plant biomass and N content inside and outside grazing cages over 13 yr, we estimate that cattle stocked at 0.65 animal unit months (AUM) · ha^?1 consumed 3.34 kg N · ha^?1 · yr^?1. Using an independent animal-based method, we estimate that cattle consumed 3.58 kg N · ha^?1 · yr^?1 for the same stocking rate and years. A global positioning system tracking study revealed that cattle spent an average of 27% of their time in pasture corners or adjacent to water tanks, even though these areas represented only 2.5% of pasture area. Based on these measurements, we estimate that cattle stocked at 0.65 AUM · ha^?1 during the summer can remove 0.60 kg N · ha^?1 in cattle biomass gain and spatially redistribute 0.73 kg N · ha^?1 to areas near corners and water tanks. An additional 0.17 kg N · ha^?1 can be lost as NH₃ volatilization from urine patches. Cumulatively, these cattle-mediated pathways (1.50 kg N · ha^?1) may explain the imbalance between current estimates of atmospheric inputs and trace gas losses. While NO_x emission remains the largest pathway of N loss, spatial N redistribution by cattle and N removed in cattle biomass are the second and third largest losses, respectively. Management of cattle-mediated N fluxes should be recognized as one means to influence long-term sustainability of semiarid rangelands.     

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.     

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.     

Preference among 7 bait flavors delivered to domestic dogs in Arizona: Implications for oral rabies vaccination on the Navajo Nation

Less than 20% of the domestic dogs on tribal lands in the United States are vaccinated against rabies. One method to increase vaccination rates may be the distribution of oral rabies vaccines (ORVs). ONRAB^® (Artemis Technologies, Inc., Ontario, Canada) is the primary ORV used in Canada to vaccinate striped skunks and raccoons. To investigate the potential use of ONRAB^® ORV baits to vaccinate feral domestic dogs against rabies on tribal lands and beyond, we performed a flavor preference study. A total of 7 bait flavors (bacon, cheese, dog food, hazelnut, sugar-vanilla, peanut butter, and sardine) were offered in pairs to 13 domestic dogs. Each dog was offered all possible combinations of bait pairs over a period of 10 days, with each bait offered 6 times. The proportion of times each bait was consumed first by individual dogs was calculated and comparisons among dogs were conducted using the MIXED procedure in SAS (SAS Institute, Cary, NC). Pairwise comparisons between baits were performed using “contrast” statements with sugar-vanilla flavor as the default for comparison. Type 3 tests of fixed effects showed a significant treatment effect (F_6,72 = 9.74, P < 0.0001). Sugar-vanilla was selected first during 14% of the offerings and exhibited the least preference among all bait types (F_1,72 = 22.46, P < 0.0001). Dog food was selected first 56% of the time, and more frequently than all other bait types (F_1,72 = 13.09, P = 0.0005).     

The use of an acoustic device to identify the epidural space in cattle

Twelve healthy cattle (weighing 188–835 kg) were placed in stocks and sedated with xylazine. Caudal epidural puncture was performed using an acoustic device that indicated a decrease in resistance with a change in pitch. Lidocaine was injected to verify correct needle placement by assessing needle prick stimuli applied on the left and right side of the tail root and the perineal region, and the loss of tail and anal sphincter tone. Pressure measurements were recorded during penetration of the different tissue layers and in the epidural space. A clear and sudden decrease in the pitch of the acoustic signal was audible in all 12 cattle. All cows showed clinical effects indicating successful epidural anaesthesia. The pressure in the epidural space after puncture was ?19 ± 10 mm Hg. The device may be of assistance in identifying the epidural space in cattle.     

Aspen Recovery Since Wolf Reintroduction on the Northern Yellowstone Winter Range

Quaking aspen (Populus tremuloides Michx.) recruitment and overstory stem densities were sampled in 315 clones in 1991 and 2006 on 560 km² of the Northern Yellowstone Winter Range (NYWR). A primary objective was to observe if aspen status had improved from 1991 to 2006: evidence of a wolf (Canis lupus) caused trophic cascade. Recruitment stems (height > 2 m and diameter at breast height < 5 cm) represent recent growth of aspen sprouts above elk (Cervus elaphus) browsing height, whereas overstory stems (all stems > 2 m) represent the cohort of stems, which will insure the sustainability of the clone. Overstory stem densities declined by 12% (P = 0.04) on the landscape scale when compared with paired t-tests. Overstory stems declined in 58% of individual clones and in 63% of the 24 drainages of the study area. The second objective was to determine which factors influenced changes in aspen density. Winter ungulate browsing (P = 0.0001), conifer establishment (P = 0.0001), and cattle (Bos spp.) grazing (P = 0.016) contributed to the decline in overstory stem densities when analyzed using a mixed effects model of log transformed medians. Eighty percent of the clones were classified as having medium to high browsing levels in 1991, whereas 65% of the clones received a similar rating in 2006, possibly due to the reduced NYWR elk population. Aspen recruitment has increased in some 2–10 km² areas, but not consistently. Our study found that a trophic cascade of wolves, elk, and aspen, resulting in a landscape-level recovery of aspen, is not occurring at this time.     

The Epidemiological Importance of Bats in the Transmission of Rabies to Dogs and Cats in the State of São Paulo,Brazil, Between 2005 and 2014

In Brazil, rabies control in dogs and cats was pioneered by the state of São Paulo with the adoption of the Pan American Health Organization recommendations for prophylaxis and control, which led to a reduction in rabies cases from 1994 onwards. As a result of these measures, the rabies virus (RABV) genetic lineage associated with dogs has not been found in the state since 1998, and all the cases in domestic animals reported since then have been caused by bat‐associated lineages of RABV. In the light of this, this study sought to investigate rabies cases in dogs and cats in the state of São Paulo between 2005 and 2014 and identify the associated transmission cycles by characterizing the RABV lineages responsible for these cases. Nine samples from dogs (n = 5) and from cats (n = 4) were collected between 2005 and 2014. The tenth animal, a rabid cat, was analysed by a different laboratory. The N gene nucleotide sequences obtained were analysed with the neighbor‐joining algorithm and Kimura 2‐parameter model using the MEGA 6 program. Phylogenetic analysis revealed that the genetic lineages identified in all the samples were those circulating in Brazilian bats. The findings of this study demonstrate that bats play an important role in the transmission of rabies to domestic animals in São Paulo state and that emphasis should be placed on the implementation of public policies to support surveillance of chiropterans for rabies.     

Neospora caninum DNA detection by TaqMan real-time PCR assay in experimentally infected pregnant heifers

Neosporosis has been considered the main cause of abortion between the first and the second trimester of pregnancy in cattle. Therefore, the objective of this study was to identify the presence of Neospora caninum DNA obtained from experimental models based on the evaluation of different areas of the fetal nervous system and organs from heifers previously inoculated with NC-1 after or before insemination. This study was performed with Hereford × Nelore (n = 29) heifers and all animals were considered free of diseases at the beginning of the experiment. All animals were bred by fixed-time artificial insemination (TAI) and allocated as follows: (a) seronegative heifers subjected to TAI (TAI, n = 9), (b) heifers infected with N. caninun 60 days prior to TAI (NC-1 + TAI, n = 9), and (c) heifers submitted to TAI and infected with N. caninum 60 days later (TAI + NC-1, n = 11). The pregnancy was confirmed by transrectal ultrasonography 35 days after TAI and evaluated every 30 days until the end of gestation. Fetuses were collected surgically at 170 days of gestation, and immediately necropsied to remove tissues aseptically. Samples of the central nervous system (CNS), heart, kidney, lung, liver, skeletal muscle and caruncle were collected for DNA extraction. Days of gestation at abortion and interval from abortion to first insemination were examined by Student's t-test. At 35 days of gestation the pregnancy rates in the group NC-1 + TAI (4/9, 44.4%) was lower than in the control group (8/9, 88.8%, P < 0.05). At 60 days, the pregnancy rates in the NC-1 + TAI group (0/4, 0%) was lower compared to TAI + NC-1 (5/7, 71.4%) and control (6/8, 75.0%) groups (P < 0.05). Animals from the group NC-1 + TAI were re-inseminated 60 days after the first TAI. After pregnancy losses throughout the study, 5 animals (TAI), 3 animals (NC-1 + TAI) and 5 animals (TAI + NC-1) maintained pregnancy until 170 days of gestation. TaqMan RT-PCR demonstrated the presence of N. caninum DNA in the medulla and right posterior cortex in 3 out of 5 fetuses from the TAI + NC-1 group. We concluded that heifers infected after TAI had a higher incidence of the parasite at the fetus CNS. Identification of N. caninum by TaqMan RT-PCR would assist in the investigation of infection and in the evaluation of vaccines or therapeutic drugs to control neosporosis in cattle.     

Blood-feeding patterns of horse flies in the French Pyrenees

Horse flies can mechanically transmit Besnoitia besnoiti, the agent of bovine besnoitiosis. Although previously limited to enzootic areas, especially the French Pyrenees Mountains, bovine besnoitiosis is now considered a re-emerging disease in western Europe. To improve understanding of the role of horse flies as mechanical vectors, this study investigated their blood-feeding ecology in the eastern French Pyrenees, in two high-altitude summer pastures whose main domestic ungulates were cattle, and in a wildlife park with native fauna. Species-specific PCR assays were conducted to identify the sources of blood meals: wild boar, horse, cattle (or bison), sheep (or mouflon), goat, red deer, roe deer and izard (or Pyrenean chamois). In La Mouline pasture, tabanids (N = 20) fed on red deer (70%) and cattle (30%). In Mantet pasture, tabanids (N = 24) fed on cattle (52%), red deer (20%), wild boar (16%), horse (8%) and sheep (4%). In the wildlife park, Tabanus bromius (N = 32), the most abundant species collected, fed on red deer (85%), bison (9%) and wild boar (6%). Despite relatively high densities in both the pastures and in the wildlife park, small wild ungulates (izard, mouflon and roe deer) were not detected as a source of blood meals. Only two mixed blood meals were identified in two specimens of T. bromius: cattle/horse for the specimen collected in the pastures, and bison/wild boar for the specimen collected in the wildlife park. Our findings showed that tabanids display a level of opportunistic feeding behaviour, in addition to a preference for red deer, the latter being particularly true for Philipomyia aprica, the most abundant species collected in the pastures.     

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.     

Apparent seroprevalence,isolation and identification of risk factors for brucellosis among dairy cattle in Goa,India

Brucellosis is a highly contagious zoonotic infection affecting livestock and human beings. The disease has been reported worldwide except in few countries where it has been eradicated. The prevalence of brucellosis among cattle from 11 farms having a history of abortions was studied. A total of 481 samples comprising of blood, milk, vaginal swabs, vaginal discharges, placental tissues and fetal tissues were collected from 296 animals. Clinical samples were processed for the isolation of Brucella. Serum samples (n = 296) were tested by Rose Bengal Plate Test (RBPT) and indirect ELISA. A total of 90 (30.40%) and 123 (41.55%) samples were positive by RBPT and indirect ELISA, respectively. Also 27.02% samples were positive by both the tests. Brucella isolates (n = 8) were recovered from clinical samples using Brucella selective media. All the isolates demonstrated PCR amplification for the bcsp31 and IS711 genes. Amplification of Brucella abortus specific primer was demonstrated by all the isolates in AMOS PCR indicating isolates to be of either B. abortus biotype 1, 2 or 4. Risk factors for transmission of brucellosis among cattle population were studied by field surveys. It was observed that lack of awareness about brucellosis (OR = 8.739, P = 0.138) and inadequate floor space (OR = 0.278, P = 0.128) were crucial risk factors for transmission of bovine brucellosis.