Campylobacter infection in a closed dog breeding colony

Most dogs in a closed breeding unit were shown to be asymptomatic excretors of campylobacter organisms by eight weeks old. Increasing serum antibody levels, which were correlated with the excretion of organisms, were demonstrated in the puppies and serum antibodies were also demonstrated in adult dogs. The significance of these findings with respect to the pathogenicity of campylobacter in dogs and their zoonotic implications are discussed.     

LARYNGEAL ADENOCARCINOMA IN A DOG

Laryngeal adenocarcinoma was diagnosed in a 5-year-old golden retriever dog with no history of respiratory or pharyngeal difficulties. Radiographically the basihyoid bone was destroyed by the neoplasm, and extensive soft tissue mineralization ventral to the larynx was also present. Complete surgical resection was not possible due to diffuse involvement of the tongue and larynx. Cobalt-60 teletherapy was used for treatment of the tumor. There was no clinical evidence of tumor regrowth at approximately 12 months post treatment. This is an unusual example of primary laryngeal neoplasia due to the absence of clinical respiratory abnormalities and the aggressive destruction of the basihyoid bone.     

Field variability and vulnerability index to identify regional precision agriculture opportunity

Innovations in precision agriculture (PA) have created opportunities to achieve a greater understanding of within-field variability. However, PA adoption has been hindered by uncertainty about field-specific performance and return on investment. Uncertainty could be better addressed by using innovative analyses that provide insights into variability among fields and across a region. The objectives of this research were to: (1) generate a within-field soil clay-content variability index (VI_c), (2) create a regional-scale growing-season precipitation variability index (VI_p), and (3) integrate the soil and weather indices with the USDA NRCS soil erosion vulnerability index (SVI) to produce a final index that incorporated both variability and vulnerability (VVI). The interpretation of the outcomes represented by each objective supports unique decisions that land managers may consider for reducing uncertainty about implementing PA. All indices were derived using publically available information for Missouri, USA. The VI_c was the ratio between the maximum and minimum clay content within fields. The VI_p was calculated as the standard deviation of the total growing-season precipitation from 2006 to 2015. Significant clustering of VI_c and VI_p were observed along the Missouri River corridor, northeast and northwest Missouri. Fields with high VVI were mostly in the claypan soil region of northeast Missouri, and along a portion of the Missouri River dominated by loess soils on steep slopes. Southeast Missouri displayed the greatest diversity in soil and weather variability, but had low vulnerability. This research could be used as a decision-support tool to aid producers and PA service and product providers in determining where PA opportunities exist.     

Bayesian analysis of within-field variability of corn yield using a spatial hierarchical model

Understanding relationships of soil and field topography to crop yield within a field is critical in site-specific management systems. Challenges for efficiently assessing these relationships include spatially correlated yield data and interrelated soil and topographic properties. The objective of this analysis was to apply a spatial Bayesian hierarchical model to examine the effects of soil, topographic and climate variables on corn yield. The model included a mean structure of spatial and temporal co-variates and an explicit random spatial effect. The spatial co-variates included elevation, slope and apparent soil electrical conductivity, temporal co-variates included mean maximum daily temperature, mean daily temperature range and cumulative precipitation in July and August. A conditional auto-regressive (CAR) model was used to model the spatial association in yield. Mapped corn yield data from 1997, 1999, 2001 and 2003 for a 36-ha Missouri claypan soil field were used in the analysis. The model building and computation were performed using a free Bayesian modeling software package, WinBUGS. The relationships of co-variates to corn yield generally agreed with the literature. The CAR model successfully captured the spatial association in yield. Model standard deviation decreased about 50% with spatial effect accounted for. Further, the approach was able to assess the effects of temporal climate co-variates on corn yield with a small number of site-years. The spatial Bayesian model appeared to be a useful tool to gain insights into yield spatial and temporal variability related to soil, topography and growing season weather conditions.

RADIOGRAPHIC AND 2-D ECHOCARDIOGRAPHIC FINDINGS IN EIGHTEEN CATS EXPERIMENTALLY EXPOSED TO D. ZMMZTZS VIA MOSQUITO BITES

Eighteen cats were exposed to Dirofikria immitis infected mosquitoes. Thoracic radiography was performed prior to exposure and at 5, 7, and 9 month intervals following exposure. Immunologic testing for adult heartworm antigen was performed on days 168,195,210,224,237,254 and 271 post infection. Necropsies were performed on all cats. Adult heartworms were found in 61% of the exposed cats. Radiographic findings in heartworm positive cats included bronchointerstitial lung disease, lobar pulmonary arterial enlargement and pulmonary hyperinflation. In most heartworm positive cats, lobar arterial enlargement resolved as the disease progressed while pulmonary hyperinflation progressively became more common. Pulmonary patterns in heartworm positive cats remained abnormal throughoutthe study while abnormal pulmonary patterns resolved in over 50% of the heartworm negative cats. Cardiomegaly was seen in less than 50% of the cats with adult heartworms at necropsy. This study suggests that the radiographic appearance of heartworm disease is variable and radiographic changes are dependent on the time post infection at which cats are evaluated. Echocardiographic examinations were randomly performed on 16 of 18 cats. Heartworms were identified in 7 cats. No false positive identifications were made. Persistent pulmonary disease accompanied by resolving vascular disease in heartworm cats with pulmonary hyperinflation may be difficult to distinguish from cats with feline allergic lung disease. Echocardiograms may be helpful in identifying adult heartworms in cats in which the radiographic signs or immunodiagnostic data are insufficient to provide a diagnosis.     

Hepatobiliary Scintigraphy in the Evaluation of Feline Liver Disease

Hepatobiliary scintigraphy (HBS) was performed in 10 cats with histologically documented hepatobiliary disease. The scintigraphic patterns were classified into one of 5 categories: normal, primary hepatocellular dysfunction, primary in-trahepatic cholestasis, mixed hepatocellular and intrahe-patic cholestasis, and extrahepatic obstructive patterns. Initial attempts were made to correlate specific disease entities with HBS patterns, but a consistent relationship could not be determined. A correlation between the histological severity of a given hepatic disease and the HBS pattern was made. All cats (n = 5) with a mixed hepatocellular and intra-hepatic cholestasis scintigraphic pattern with normal gallbladder function had a histologically severe form of their individual hepatic disease. Three of the 4 cats with an intra-hepatic cholestasis pattern and normal hepatocellular and gallbladder function had histologically mild or moderate forms of their individual hepatic disease. One cat had an extrahepatic obstructive pattern where no radiopharmaceu-tical was identified in the gallbladder or small intestine by 3 hours postinjection. This study suggests that HBS can be useful in cats with hepatobiliary disease to assess the severity of hepatic dysfunction, and to determine if extrahepatic biliary obstruction is present. Correlation between HBS patterns and specific disease entities such as hepatic lipidosis or cholangitis-cholangiohepatitis syndrome could not be made in this study.     

Crossing the boundaries

In the past, research on zoonotic diseases has been fragmented. Teresa Belcher and Diane Newell discuss the formation of Med-Vet-Net, a "virtual institute", which aims to integrate activity between researchers in human and veterinary medicine across the European Union.     

Plant-derived enzyme inhibitors and lectins for resistance against plant-parasitic nematodes in transgenic crops

Due to increasing restrictions on the use of toxic and expensive nematicides, there is now a greater than ever need for crop cultivars that are resistant to plant-parasitic nematodes. Genetically engineered nematode resistance is not as well developed as other engineered traits but, even so, the first genetically modified plants with enhanced nematode resistance have been produced and tested. Plant-derived enzyme inhibitor and lectin genes are being evaluated for their ability to confer broad-spectrum nematode resistance in transgenic crop plants. Early indications are that these are likely to be effective. Gene pyramiding has potential to increase field durability and to widen the spectrum of nematodes controlled by any one transgenic line. © 1998 SCI.