MOOSE EXPERIMENTALLY INFECTED WITH GIANT LIVER FLUKE (FASCIOLOIDES MAGNA)

Moose (Alces alces) are abnormal, dead-end hosts of the giant liver fluke Fascioloides magna. The worms migrate extensively in moose causing considerable hepatic tissue damage before eventually dying. Few reach sexual maturity and eggs are seldom, if ever, passed in feces. Occurrence of the parasite in moose depends on the presence of a competent definitive host and suitable aquatic snail intermediate hosts of the genus Lymnaea. There is no clinical evidence that F. magna kills moose although the considerable tissue pathology seen in some heavily infected livers is suggestive that they do. In this study, 2 farm-reared calves (2 months old) and a yearling moose (15 months old) were given 50, 110, and 225 F. magna metacercariae, respectively, and observed for 12.5-16 months. No outward signs of disease were observed. The livers of the 2 animals infected as calves were swollen and contained bloody tracks, extensive fibrosis, and capsules; 1 and 11 immature flukes were recovered. The liver of the animal infected as a yearling had 3 large, thick-walled capsules but no flukes. Weight gain and behaviour of all were similar to those of uninfected farm-reared moose. Known aspects of the biology of this parasite and our experimental results suggest that F. magna is unlikely to have been a major factor in the recent moose decline in northwestern Minnesota

MOOSE EXPERIMENTALLY INFECTED WITH GIANT LIVER FLUKE (FASCIOLOIDES MAGNA)

Moose (Alces alces) are abnormal, dead-end hosts of the giant liver fluke Fascioloides magna. The worms migrate extensively in moose causing considerable hepatic tissue damage before eventually dying. Few reach sexual maturity and eggs are seldom, if ever, passed in feces. Occurrence of the parasite in moose depends on the presence of a competent definitive host and suitable aquatic snail intermediate hosts of the genus Lymnaea. There is no clinical evidence that F. magna kills moose although the considerable tissue pathology seen in some heavily infected livers is suggestive that they do. In this study, 2 farm-reared calves (2 months old) and a yearling moose (15 months old) were given 50, 110, and 225 F. magna metacercariae, respectively, and observed for 12.5-16 months. No outward signs of disease were observed. The livers of the 2 animals infected as calves were swollen and contained bloody tracks, extensive fibrosis, and capsules; 1 and 11 immature flukes were recovered. The liver of the animal infected as a yearling had 3 large, thick-walled capsules but no flukes. Weight gain and behaviour of all were similar to those of uninfected farm-reared moose. Known aspects of the biology of this parasite and our experimental results suggest that F. magna is unlikely to have been a major factor in the recent moose decline in northwestern Minnesota

SALMON POISONING DISEASE: RESEARCH ON A POTENTIAL METHOD OF LETHAL CONTROL FOR COYOTES

Salmon poisoning disease (SPD) was tested as a potential method of lethal control for coyotes (Canis latrans). Fresh fish containing the agents for SPD was fed to 72 captive adult coyotes. Coho (Oncorhunchus kisutch) and steel head salmon (Salmo gairdneri) from Oregon hatcheries were the principal species of fish used. Coyotes that ate the fish developed observable signs of SPD in a mean of 8 days. The overall rate of mortality was 50%, and death occurred in a mean of 20 days from consuming fish. Coyotes that died from SPD lost a mean of 32% of their body weight during the course of the disease. Other coyotes were fed preserved fish samples or administered oral or intraperitoneal treatments of lymph node matter from coyotes that died from SPD. In light of the relatively low rate of mortality observed, feeding coyotes fish to cause death from SPD appears to be a method of questionable value for controlling numbers of adult coyotes in areas of livestock production unless fish with a highly virulent strain of the SPD agent can be obtained

Introduction to General Field Procedures (Field Manual of Wildlife Diseases)

Section 1 of the Manual provides basic information regarding general field procedures for responding to wildlife disease events. Field biologists provide a critical linkage in disease diagnostic work and greatly affect the outcome of the laboratory efforts by the quality of the materials and information that they provide. The chapters in this section are oriented towards providing guidance that will assist field biologists in gathering the quality of information and specimens that are needed. Readers will find information regarding what to record and how; guidance for specimen collection, preservation, and shipment; and how to apply euthanasia when such actions are warranted. Disease operations are managed at the field level and they can be aided by general preplanning that can be utilized when disease emergencies arise; therefore, contingency planning is included within the Disease Control Operations chapter. Disease control techniques, including equipment that is used, are the main focus for this highly illustrated chapter. Section 1 is concluded with a chapter about the proper care and use of wildlife in field research. The guidelines provided address the continual need to consider animal welfare in all aspects of wildlife management

Salmon poisoning disease: research on a potential method of lethal control for coyotes

Salmon poisoning disease (SPD) was tested as a potential method of lethal control for coyotes (Canis latrans). Fresh fish containing the agents for SPD was fed to 72 captive adult coyotes. Coho (Oncorhunchus kisutch) and steelhead salmon (Salmo gairdneri) from Oregon hatcheries were the principal species of fish used. Coyotes that ate the fish developed observable signs of SPD in a mean of 8 days. The overall rate of mortality was 50%, and death occurred in a mean of 20 days from consuming fish. Coyotes that died from SPD lost a mean of 32% of their body weight during the course of the disease. Other coyotes were fed preserved fish samples or administered oral or intraperitoneal treatments of lymph node matter from coyotes that died from SPD. In light of the relatively low rate of mortality observed, feeding coyotes fish to cause death from SPD appears to be a method of questionable value for controlling numbers of adult coyotes in areas of livestock production unless fish with a highly virulent strain of the SPD agent can be obtained

Exposure of bighorn sheep to domestic goats colonized with <i>Mycoplasma ovipneumoniae</i> induces sub-lethal pneumonia

<div><p>Background</p><p>Bronchopneumonia is a population limiting disease of bighorn sheep (<i>Ovis canadensis</i>) that has been associated with contact with domestic Caprinae. The disease is polymicrobial but is initiated by <i>Mycoplasma ovipneumoniae</i>, which is commonly carried by both domestic sheep (<i>O</i>. <i>aries</i>) and goats (<i>Capra aegagrus hircus</i>). However, while previous bighorn sheep comingling studies with domestic sheep have resulted in nearly 100% pneumonia mortality, only sporadic occurrence of fatal pneumonia was reported from previous comingling studies with domestic goats. Here, we evaluated the ability of domestic goats of defined <i>M</i>. <i>ovipneumoniae</i> carriage status to induce pneumonia in comingled bighorn sheep.</p><p>Methodology/Principal findings</p><p>In experiment 1, three bighorn sheep naïve to <i>M</i>. <i>ovipneumoniae</i> developed non-fatal respiratory disease (coughing, nasal discharge) following comingling with three naturally <i>M</i>. <i>ovipneumoniae</i>-colonized domestic goats. Gross and histological lesions of pneumonia, limited to small areas on the ventral and lateral edges of the anterior and middle lung lobes, were observed at necropsies conducted at the end of the experiment. A control group of three bighorn sheep from the same source housed in isolation during experiment 1 remained free of observed respiratory disease. In experiment 2, three bighorn sheep remained free of observed respiratory disease while comingled with three <i>M</i>. <i>ovipneumoniae-</i>free domestic goats. In experiment 3, introduction of a domestic goat-origin strain of <i>M</i>. <i>ovipneumoniae</i> to the same comingled goats and bighorn sheep used in experiment 2 resulted in clinical signs of respiratory disease (coughing, nasal discharge) in both host species. At the end of experiment 3, gross and histological evidence of pneumonia similar to that observed in experiment 1 bighorn sheep was observed in both affected bighorn sheep and domestic goats.</p><p>Conclusions/Significance</p><p><i>M</i>. <i>ovipneumoniae</i> strains carried by domestic goats were transmitted to comingled bighorn sheep, triggering development of pneumonia. However, the severity of the disease was markedly milder than that seen in similar experiments with domestic sheep strains of the bacterium.</p></div