Bartonella species antibodies and hyperglobulinemia in privately owned cats

Background

Bartonella species are zoonotic agents and primary pathogens in cats. Hyperglobulinemia has been associated with bartonellosis in humans and cats.

Hypothesis/Objectives

To evaluate for associations between Bartonella species immunoglobulin G (IgG) antibodies and serum biochemistry panel results in privately owned cats.

Animals

1,477 privately owned cats.

Methods

Residual sera were collected after biochemical evaluation for this prospective, cross‐sectional serosurvey. Bartonella species IgG ELISA was performed with a cutoff value of ≥1 : 64. Stepwise logistic regression analysis was performed with the endpoint titer as the outcome variable. The final statistical model included age, albumin, ALP activity, ALT activity, bilirubin, creatinine, glucose, and globulin as covariates. Serum protein electrophoresis was performed with serum from 50 cats with and without antibodies to Bartonella species and hyperglobulinemia. Sera from cats seropositive to Bartonella species and with hyperglobulinemia were assessed for evidence of exposure to other infectious agents associated with hyperglobulinemia.

Results

Risk of seropositivity to Bartonella species was positively associated with the natural log of globulin concentration (OR = 11.90, 95% CI 6.15–23.02, P < .0001), and inversely associated with the natural log of glucose concentration (OR = 0.66, 95% CI 0.50–0.87, P = .004). Another explanation for hyperglobulinemia was not identified for most cats with Bartonella species antibodies. Hyperglobulinemia was primarily caused by polyclonal gammopathy in cats that were seronegative and seropositive for Bartonella species.

Conclusions and Clinical Importance

Hyperglobulinemia was significantly associated with seropositivity to Bartonella species. Testing for bartonellosis is warranted in cats with unexplained hyperglobulinemia and clinical or laboratory findings suggestive of bartonellosis.     

Evaluation of phosphorus mobilization potential in rewetted fens by an improved sequential chemical extraction procedure

After rewetting of peatlands, phosphorus (P) pore‐water concentrations were up to three orders of magnitude greater than under pristine conditions. It was hypothesized that different mobilization processes such as ion‐exchange reactions, biotic/abiotic redox reactions, acidification and ongoing anaerobic decomposition of particulate organic matter by hydrolytic cleavage and fermentation might be responsible. To identify P pools in peat samples of varying degrees of decomposition, we modified and improved a sequential chemical extraction method that allowed conclusions on potential mobilization mechanisms in rewetted peatlands. The results indicated that the earlier drainage of rewetted fens strongly increased the P mobilization potential in the upper decomposed peat layers. Accordingly, the amount of P bound to redox‐sensitive (bicarbonate/dithionite soluble) compounds (BD‐P) was, on average, one order of magnitude greater in decomposed peat of rewetted fens (5.4–14.3 μmol P g^?1 dry matter or DM) than in underlying less‐decomposed peat layers (0.2–1.9 μmol P g^?1 DM) or slightly decomposed peat derived from pristine fens (0.4–2.0 μmol P g^?1 DM). The BD‐P fraction found in the upper very decomposed peat layers appears to be most important for P mobilization in rewetted fens and accounted for 85% of the variability of P mobilization rates. Despite uncertainties regarding P diagenetic processes in peat, as well as the development of microbial decomposition processes, in the long‐term, high pore‐water P concentrations can be expected in rewetted fens for decades to come.     

Recent advances in the biological control of fusarium wilts

Studies of soils suppressive to fusarium wilts have indicated that the phenomenon is fundamentally microbiological in nature, resulting from complex microbial interactions between the pathogen and all, or a part of, the saprophytic microflora. Many groups of micro-organisms have been proposed as having a role in this process. The most consistent results show that non-pathogenic Fusarium oxysporum and fluorescent pseudomonads are the main agents for biological control. Each group has been effective in reducing the severity of fusarium diseases in several crops under experimental conditions. All the problems associated with application of antagonists have not yet been solved, but special situations exist where biological control could be applied soon. In Europe, the present development of soil-less systems to grow tomatoes, cucumbers, carnations and a few other species of flowers and vegetables in greenhouses, offers a unique opportunity to use antagonists. A strain of non-pathogenic Fusarium isolated from soil from Chǎteaurenard can be established in the soil-less substrates, or in the potting mixtures, before transplanting the plants and in these conditions can prevent colonization of the substrates by the pathogens. It gave good control of fusarium wilts of tomatoes, carnations and cyclamens, and of crown and root rot of tomatoes due to F. oxysporum f.sp.radicis lycopersici. This non-pathogenic strain, produced by liquid fermentation and mixed with talc, is easy to introduce into soil-less substrates after having been suspended in water or in liquid fertilizer. Experiments have been under way in commercial greenhouses for several years, but it will be necessary to wait at least two more years to complete all the tests required for the registration of the product as a biopesticide. Similar experiments have been conducted with a strain of fluorescent pseudo-monad also isolated from the soil of Chǎteaurenard, which shows poor antagonistic effect when applied alone but consistently improves disease control when applied in combination with the non-pathogenic Fusarium. In fact, application of both antagonists together always gave total control of the diseases, the yield in the treated plots being equal to that in the healthy control. These experiments show that combining antagonists can improve the consistency of biological control.     

Isolation of differentially expressed genes during interactions between tomato cells and a protective or a non-protective strain of Fusarium oxysporum

Pathogenic isolates of Fusarium oxysporum applied on a non-host plant species, as soil-borne non-pathogenic isolates, are able to protect this plant against pathogenic strains inducing wilts. Several modes of action contribute to the biocontrol activity of these protective strains; however the genetic basis of the biocontrol mechanisms is far from being understood. The aim of this study was to identify genes involved in biocontrol activity of F. oxysporum using an original model made of Fom24, a strain protective on tomato and its mutant rev157 which has lost its protective capacity. A Rapid Subtractive Hybridization (RaSH) approach was chosen to identify genes up-regulated in the protective or in the non-protective interaction when germinated conidia of either Fom24 or rev157 are confronted to tomato cell cultures. A total of 86 up-regulated sequences were generated, 42 and 44 from the protective and the non-protective interaction respectively. Homology searches led to identification of both plant and fungal genes that were grouped according to their putative functions. Among plant genes, those involved in plant response to stresses were the most abundant. Expression profiles of genes homolog to a basic endochitinase, a ferredoxine-NADP(H) reductase (FNR), an ATP synthase and the RPM1-interacting protein 4 (RIN4) were confirmed by Northern blotting. A large proportion of fungal sequences were encoding genes of unknown function; among other, those involved in response to oxidative stress and a gene putatively encoding an enolase are the most promising to further study their potential role in the protective interaction between F. oxysporum and tomato.     

Pest control by predators and parasites

The feasibility of controlling the two-spotted spider mite in apple orchards by inundative releases of the phytoseiid predatorPhytoseiulus persimilis, was studied in a field trial in northern Israel. Half a million predators released per acre, maintained high populations forca 2 months until the spider mite population dropped below the economic threshold.P. persimilis demonstrated a dispersal capacity of at least 90 m from its original release site. The ability of the predator to switch to alternative prey (the European red mite) and the economic feasibility of this non-chemical approach to spider mite control, are discussed.     

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.