Pyrethroid Exposure Reduces Growth and Development of Monarch Butterfly (Lepidoptera: Nymphalidae) Caterpillars

Insecticide exposure has been identified as a contributing stressor to the decline in the North American monarch butterfly Danaus plexippus L. (Lepidoptera: Nymphalidae) population. Monarch toxicity data are currently limited and available data focuses on lethal endpoints. This study examined the 72-h toxicity of two pyrethroid insecticides, bifenthrin and β-cyfluthrin, and their effects on growth and diet consumption. The toxicity of bifenthrin to caterpillars was lower than β-cyfluthrin after 72 h. Survival was the most sensitive endpoint for bifenthrin, but diet consumption and caterpillar growth were significantly reduced at sublethal levels of β-cyfluthrin. Using AgDRIFT spray drift assessment, the aerial application of bifenthrin or β-cyfluthrin is predicted to pose the greatest risk to fifth-instar caterpillars, with lethal insecticide deposition up to 28 m for bifenthrin and up to 23 m for β-cyfluthrin from treated edges of fields. Low boom ground applications are predicted to reduce distances of lethal insecticide exposure to 2 m from the treated field edge for bifenthrin and β-cyfluthrin. Growth and survival of fifth-instar monarch caterpillars developing within the margins of a treated field may be significantly impacted following foliar applications of bifenthrin or β-cyfluthrin. These findings provide evidence that pyrethroid insecticides commonly used for soybean pest control are a potential risk to monarch caterpillars in agricultural landscapes.     

Surgical decompression,with or without adjunctive therapy,for palliative treatment of primary vertebral osteosarcoma in dogs

Vertebral osteosarcoma (OSA) is the most common primary vertebral tumor in dogs, however studies examining the survival time after surgical decompression of these tumors are limited. There is also limited information regarding the benefit of adjunctive treatments such as radiation therapy or chemotherapy in these patients. The goal of this study was to determine survival time of dogs with primary vertebral OSA after palliative decompressive surgery alone and combined with radiation therapy and/or chemotherapy. Records from 22 client‐owned dogs diagnosed with primary vertebral OSA and treated with decompressive surgery were collected retrospectively from eight referral institutions. Survival time was assessed for dogs treated with surgery alone as well as dogs who received adjunctive radiation therapy and/or chemotherapy. Median survival time in the 12 dogs treated with surgery alone was 42 days (range: 3‐1333 days). The three dogs treated with surgery and chemotherapy had a median survival time of 82 days (range: 56‐305 days). Only one dog was treated with surgery and radiation therapy; this dog survived 101 days. Six dogs were treated with surgery, radiation therapy and chemotherapy; these dogs had a median survival time of 261 days (range: 223‐653 days). Cause of death in all cases that survived the initial postoperative period was euthanasia secondary to confirmed or suspected tumor regrowth. The results of this study suggest that definitive radiation therapy, possibly combined with concurrent chemotherapy, significantly improves survival in dogs treated with palliative decompressive surgery for vertebral OSA and should be the treatment of choice in selected cases.     

Fecal incontinence and spinal cord abnormalities in seven dogs

Seven dogs with fecal incontinence and abnormal gaits were evaluated. Fecal incontinence was characterized as defecation of normal stools without posturing. Duration of clinical signs prior to evaluation ranged from 5 months to 3 years. Five dogs had upper motor neuron (UMN) paraparesis, and 2 dogs had UMN tetraparesis. With magnetic resonance imaging, spinal cord abnormalities primarily involving the dorsal aspect of the spinal cord were identified in all dogs. Five dogs had focal abnormalities, and 2 dogs had diffuse abnormalities of the spinal cord. Of the dogs with focal spinal cord lesions, 4 had cystic spinal cord abnormalities and 1 had a meningioma. Surgery was performed on all dogs with focal lesions; 4 of the 5 dogs had resolution of fecal incontinence after surgery. Results in these dogs suggest that fecal incontinence can be associated with spinal cord abnormalities and, depending on the characteristics of the lesion, can resolve after surgical treatment of the abnormality.     

Recent advances in the understanding of Chlamydophila pecorum infections, sixteen years after it was named as the fourth species of the Chlamydiaceae family

Chlamydophila pecorum found in the intestine and vaginal mucus of asymptomatic ruminants has also been associated with different pathological conditions in ruminants, swine and koalas. Some endangered species such as water buffalos and bandicoots have also been found to be infected by C. pecorum. The persistence of C. pecorum strains in the intestine and vaginal mucus of ruminants could cause long-term sub-clinical infection affecting the animal’s health. C. pecorum strains present many genetic and antigenic variations, but coding tandem repeats have recently been found in some C. pecorum genes, allowing C. pecorum strains isolated from sick animals to be differentiated from those isolated from asymptomatic animals. This review provides an update on C. pecorum infections in different animal hosts and the implications for animal health. The taxonomy, typing and genetic aspects of C. pecorum are also reviewed.     

Electron microscopic observation of the respiratory tract of SPF piglets inoculated with Mycoplasma hyopneumoniae.

Seven hysterectomy derived piglets were repeatedly challenged with Mycoplasma hyoneumoniae during the first week of life. Samples of trachea, bronchi and lung tissue collected 2–11 weeks post-inoculation (p.i.) were examined using light and electron microscopy. Autoradiography was used to study in more detail the site of M. hyopneumoniae multiplication. Gross lesions were observed in lung tissue and were characterized by hyperplasia of the epithelium and an increased mononuclear cell accumulation in perivascular and peribronchiolar areas. Mild lesions of the trachea and the bronchi, including epithelial hyperplasia and infiltration of the lamina propria by inflammatory cells, were noted.

Electron microscopy showed that, 2–6 weeks p.i., changes in the mid-trachea and bronchi surface consisted of the loss of cilia. Mycoplasmas covered tufts of cilia remaining on the epithelial cell surface. Scanning and transmission electron micrographs showed that they were predominantly found closely associated with the top of cilia. No specialized terminal structure could be seen and no mycoplasma cells were identified lying free in the lumen nor in close contact with the plasma membrane of cells of microvilli. Some fine fibrils radiating from one mycoplasma to another or to cilia were seen at higher magnification by scanning electron microscopy. Six to eleven weeks p.i., a disrupted epithelial surface lacking cilia was observed. Cells were desquamated and shed into the lumen with cellular remains containing droplets of mucus.

Autoradiography revealed that label corresponded to the observed mycoplasma distribution. At the top of cilia, a high density of labeling was visible in the zone of high mycoplasma concentration. Therefore, incorporation of the label in the mycoplasma is proof or their multiplication in the trachea.

The intimate association between the mycoplasma and cilia may be an important factor in the pathogenesis of the disease caused by M. hyopneumoniae (swine enzootic pneumonia).     

Chloramphenicol 3. Clinical pharmacology of systemic use in the horse

The use of chloramphenicol in the horse is now prohibited as horses are classified as food-producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half-life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse.     

Global-scale genetic structure of a cosmopolitan cold-water coral species

• 1. When considering widely distributed marine organisms with low dispersal capabilities, there is often an implication that the distribution of cosmopolitan species is an artefact of taxonomy, constrained by the absence of characters for delimiting either sibling or cryptic species. Few studies have assessed the relationship among populations across the global range of the species' distribution, and the presence of oceanographic barriers that might influence gene flow among populations are underestimated.
• 2. In this study, evolutionary and ecological drivers of connectivity patterns have been inferred among populations of the cold-water coral Desmophyllum dianthus, a common and widespread solitary scleractinian species, whose reproduction strategy and larval dispersal are still poorly unknown.
• 3. The genetic structure of D. dianthus was explored using 30 microsatellites in 347 specimens from 13 localities distributed in the Mediterranean Sea and Atlantic and Pacific Oceans.
• 4. Results clearly reveal genetically differentiated populations in the Northern and Southern Hemispheres (F_ST = 0.16, F_SC = 0.01, F_CT = 0.15, P-values highly significant), and Chilean and New Zealand populations with independent genetic profiles.
• 5. Marine connectivity patterns at different spatial scales are discussed to characterize larval dispersal and gene flow through the Northern and Southern Hemispheres.

     

Shedding routes of Coxiella burnetii in dairy cows: implications for detection and control

Reliable detection of Coxiella burnetii shedders is a critical point for the control of the spread of this bacterium among animals and from animals to humans. Coxiella burnetii is shed by ruminants mainly by birth products (placenta, birth fluids), but may also be shed by vaginal mucus, milk, and faeces, urine and semen. However, the informative value of these types of samples to identify shedders under field conditions is unknown. Our aim was then to describe the responses obtained using a real-time PCR technique applied to milk, vaginal mucus and faeces samples taken from 242 dairy cows in commercial dairy herds known to be naturally infected with Coxiella burnetii, and to assess their putative associations. Positive results were found in all types of tested samples even in faeces. No predominant shedding route was identified. Among the shedder cows, 65.4% were detected as shedders by only one route. By contrast, cows with positive results for all three samples were scarce (less than 7%). Testing a cow based on only one type of biological sample may lead to misclassify it with regards to its shedding of Coxiella burnetii and thereby underestimate the risk of bacterial spread within a herd.