Speciation of Heavy Metals in Road Runoff and Roadside Total Deposition

The concentrations of Cd, Co, Cu, Pb, W and Zn were measured in road runoff and total deposition at two Swedish field sites during one year. It was found that the concentrations of most elements increased significantly during the winter, up to one order of magnitude. For cobalt and tungsten, it was found that around 90% of the total mass transport occurred during the winter, whereas for Cu, Pb, Cd, Zn and Na, the corresponding figures were 70–90, 40–80, 60–90, 50–70 and ≥99% depending on site specific conditions. The deicing salts (rock salts) did not significantly contribute to the increase in trace element concentrations. Instead, the increased concentrations were due to more intense wearing of the pavement during the winter because of the use of studded tires in combination with the chemical effects caused by the use of deicing salts. New potential elemental markers for roads and traffic are suggested.     

A monoclonal antibody-based immunoperoxidase monolayer (micro-isolation) assay for detection of type 1 and type 2 bovine viral diarrhea viruses.

A monoclonal antibody (mAb)-based immunoperoxidase monolayer assay (IPMA) for detection of bovine viral diarrhea virus (BVDV) was developed and compared with an existing bovine polyclonal antibody (pAb)-based IPMA. A pool of 5 mAbs, 4 mAbs produced to a type 1 BVDV and 1 mAb produced to a type 2 BVDV, was utilized in the mAb-IPMA. The mAbs were chosen for inclusion in the pool because of their broad cross-reactivities with type 1 and/or type 2 BVDV, their apparent avidities for antigen, their reactivity to different BVDV proteins, and their lack of competition for binding sites or their binding to unusual BVDV isolates. The mAb-IPMA outperformed the pAb-IPMA in staining, ease of reading test results, and relative sensitivity with a panel of known BVDV positive and negative sera. The relative sensitivities of the mAb-IPMA and pAb-IPMA were 100% and 93.5%, respectively, for 62 positive samples including several that were known to contain type 2 BVDV. With retesting, the pAb-IPMA gave a similar level of sensitivity as that of the mAb-IPMA. Both tests gave a specificity of 100% for 40 negative serum samples obtained from a BVDV-free herd.     

Assessment of the genetic risk and impact of lateral transmission in a valine-associated scrapie outbreak in sheep

OBJECTIVE: To characterize an outbreak of valine-associated scrapie, assess the relative risk of scrapie infection in relation to allele frequency at codon 136, and investigate lateral transmission of infection in a sheep flock within the United States. ANIMALS: 1,006 sheep. PROCEDURE: To determine genotypes, blood or semen samples were assessed via commercial testing; in 190 slaughtered sheep, scrapie status was determined via immunohistochemical evaluation of tissues. Scrapie-positive sheep born to scrapie-negative dams and sheep infected after 1 year of age were identified to assess lateral transmission. RESULTS: Genotypes were determined for codon 171 (164 sheep) or codons 136 and 171 (842 sheep). Forty-four of 160 slaughtered sheep of known genotype were scrapie positive. In these sheep, the presence of at least 1 valine allele at codon 136 (V136) was highly correlated with scrapie-positive status. Lateral transmission was the probable source of infection for 4 scrapie-positive sheep born to scrapie-negative dams and for 11 sheep in which scrapie was diagnosed at > 50 months of age. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the outbreak of scrapie was associated with a relatively high frequency of V136 in the flock, introduction of a valine-dependent scrapie strain, and the occurrence of lateral transmission. Genotyping of sheep may assist management decisions following diagnosis of scrapie in a sheep with at least 1 V136. It may be prudent to remove sheep of the diploid genotype AVQR (at codons 136 and 171) from infected flocks.     

Epidemiologic features of Campylobacter infection among cats in the upper midwestern United States

OBJECTIVE: To describe the epidemiologic features of Campylobacter infection among cats in the Minneapolis-Saint Paul metropolitan area. DESIGN: Prevalence survey. ANIMALS: 152 cats examined at 3 private veterinary clinics and an animal humane society. PROCEDURES: Fecal samples were submitted for bacterial culture for Campylobacter spp. To determine the duration of Campylobacter carriage, follow-up fecal samples were collected from cats with positive Campylobacter culture results. RESULTS: Campylobacter organisms were cultured from 37 of the 152 (24%) fecal samples. Campylobacter isolates were identified as Campylobacter upsaliensis (29 cats), Campylobacter jejuni (2), and Campylobacter coli (1); species of the remaining 5 isolates could not be determined. Campylobacter organisms were isolated from 36 of the 122 (30%) cats that were < or = 1 year old but from only 1 of the 30 (3%) cats that were > 1 year old, and shedding was more common during the summer and fall months. No association between Campylobacter shedding and clinical signs of disease was identified. For 4 of 13 cats from which follow-up fecal samples were obtained, duration of Campylobacter carriage could not be determined because Campylobacter organisms were isolated from all follow-up samples. For the remaining 9 cats, median duration of Campylobacter carriage was 44 days. CONCLUSIONS AND CLINICAL RELEVANCE: C. upsaliensis can commonly be isolated from the feces of overtly healthy kittens in the Midwest United States. Because carriage may be prolonged, veterinarians should encourage good hand hygiene among owners of cats, especially among owners with new kittens in their household.     

Agricultural performance in Tanzania under structural adjustment programs: Is it really so positive?

The performances in the food and cashcrop sectors and the availability and consumption ofagricultural inputs in Tanzania during structuraladjustment programs (1986–1996) are compared withperiods prior to this IMF/World Bank backed reform.The positive developments in the first five years ofreform appear to be not sustainable. Presentlyproductivity levels per rural capita for importantfood and cash crops are declining. There are nofurther improvements in the availability andconsumption of agricultural inputs. The removal ofsubsidies on agricultural inputs from 1991 onwards iscrucial in explaining the decline in maize production,the main food crop in Tanzania. Some assumptionsbehind the reform measures are proving to be wrong.Modifications are thus needed to improve theagricultural sector of Tanzania in a sustainable way.Structural adjustment programs usually go too far inreducing the role of the government. However,government involvement might be necessary to ensure ahigher consumption of agricultural inputs and thus abetter performance of the agricultural sector inTanzania. A higher productivity in the agriculturalsector is needed in Tanzania to avoid food securityproblems in the future.