Ehrlichial diseases of dogs

Ehrlichial diseases of dogs currently are recognized to be caused by Ehrlichia canis, Ehrlichia platys, Ehrlichia equi, and Ehrlichia risticii. Information on each disease's history, transmission, pathogenesis, clinicopathologic findings, diagnosis, therapy, and prevention is presented in this article. Ehrlichia canis is the most common cause of clinical illness. Case reports are included to illustrate common presentations of Ehrlichia canis infections.     

Comparison of worm control strategies in grazing sheep in Denmark.

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.     

Temporal study of staphylococcal species on healthy dogs

During a 1-year period, specimens were obtained monthly from 5 hair coat and 7 mucous membrane sites of 11 healthy dogs. Among 804 isolates of staphylococci, 13 species were identified. Staphylococcus intermedius was the most frequently isolated (40.2% of total isolates) coagulase-positive species, and S xylosus was the most frequently isolated (17.3%) coagulase-negative species. Moreover, S intermedius was the most frequently isolated species from the 12 sites evaluated and was isolated persistently from 8 of the 9 dogs that completed the 1-year study. On the basis of a commercial identification system, 14 profile numbers were identified for isolates of S intermedius. However, 2 profile numbers accounted for a majority (70.9%) of the isolates. Specific S intermedius biotypes identified on the basis of hemolysis, coagulase production, beta-lactamase activity, and antimicrobial susceptibility patterns were found repeatedly in 3 dogs. Seemingly, S intermedius was a resident of the normal bacterial microflora of these dogs; however, the inability to isolate S intermedius from 1 dog during the study year indicated that not all dogs harbor S intermedius as a resident microorganism.     

Detection of beta-lactamase produced by Staphylococcus intermedius

One iodometric, 2 chromogenic, and 3 acidometric methods were compared for the detection of beta-lactamase produced by Staphylococcus intermedius (n = 105) isolated from dogs. Of 575 tests performed, using the 6 methods evaluated, 316 (55.0%) were positive for beta-lactamase production. The iodometric method was the reference method. With the exception of a high correlation (r = 0.962) between 1 acidometric method and 1 chromogenic method, the 5 commercial methods had correlation coefficients less than 0.900 when comparisons were made among them. The 6 methods were in agreement for 69 (65.7%) of the isolates. Based on the findings of this study, an inexpensive, laboratory-prepared, paper strip iodometric method was as reliable as 5 commercial methods for beta-lactamase detection and is recommended for routine use in clinical laboratories.     

Sequence finishing and mapping of Drosophila melanogaster heterochromatin

Genome sequences for most metazoans and plants are incomplete because of the presence of repeated DNA in the heterochromatin. The heterochromatic regions of Drosophila melanogaster contain 20 million bases (Mb) of sequence amenable to mapping, sequence assembly, and finishing. We describe the generation of 15 Mb of finished or improved heterochromatic sequence with the use of available clone resources and assembly methods. We also constructed a bacterial artificial chromosome-based physical map that spans 13 Mb of the pericentromeric heterochromatin and a cytogenetic map that positions 11 Mb in specific chromosomal locations. We have approached a complete assembly and mapping of the nonsatellite component of Drosophila heterochromatin. The strategy we describe is also applicable to generating substantially more information about heterochromatin in other species, including humans.     

Soil organic matter effects on plant available and water soluble phosphorus

The degree of phosphorus saturation (DPS) has been shown to be a suitable initial indicator of P loss potential from agricultural soils to surface waters. In addition, several agronomic soil tests have been evaluated as environmental predictive tools. The objectives of this study were: (1) to evaluate the modified Morgan soil test, used on acid, high-aluminum soils of the northeastern United States, as a predictor of water-soluble P and (2) to determine the effect of soil organic matter (SOM) on the ability of both DPS and soil test P to predict water-soluble P. The soils were divided into three SOM classifications depending on their loss-on-ignition contents and analyzed for water-soluble P, modified Morgan soil test P, and oxalate-extractable P, Al, and Fe. The relationship between DPS and water-soluble P showed a change point at about 15% DPS, as did the relationship between DPS and modified Morgan soil test P. A DPS of 15% corresponded to about 14 mg kg⁻¹, a threshold above which water-soluble P could be expected to increase more rapidly with additional P loading. The slopes of the regression lines of water-soluble P as a function of soil test P were 0.050, 0.036, and 0.021 (mg water-soluble P kg⁻¹ soil/mg soil test P kg⁻¹) for the low, medium, and high SOM classification groups, respectively. SOM level had a less significant effect on the relationship between DPS and water-soluble P. Higher levels of SOM were associated with higher levels of oxalate-extractable Fe and Al and, therefore, higher P sorption capacities and lower DPS values, resulting in less P in solution at all soil test levels.     

Tick-borne zoonoses: Lyme disease, ehrlichiosis, and Rocky Mountain spotted fever

The primary health risk for veterinary staff and companion pet owners is exposure to ticks in the wooded/pasture areas or to ticks brought indoors by their pets. There are no proven cases of direct animal to human transmission for Lyme disease, ehrlichiosis, or Rocky Mountain spotted fever. Direct inoculation of blood from a bacteremic animal, eg, by needle stick is a theoretical, but, so far, undocumented health risk. However, veterinarians should record needle sticks or other inoculation-type injuries that occur in their practices. Prevention of Lyme disease, ehrlichiosis, Rocky Mountain spotted fever, and other tick-borne diseases depends on the avoidance of tick-infested areas and proper use of repellents and acaricides.