Assessment of iris vasculature abnormalities in dogs with diabetes mellitus.

OBJECTIVE: To identify and characterize abnormalities of iris vasculature in dogs with diabetes mellitus, compared to clinically normal, age-matched control dogs, by means of anterior segment angiography. ANIMALS: 10 dogs with naturally occurring diabetes mellitus and 10 age-matched control dogs with no ocular or systemic disease. PROCEDURES: The day before iris vasculature abnormality (IVA) assessment, all dogs underwent complete physical and ophthalmic examinations and baseline clinicopathologic analyses. For diabetic dogs, serum fructosamine concentration and a 12-hour blood glucose concentration curve were generated. The next day, all dogs were sedated and anterior segment angiography (following IV injection of indocyanine green [1 mg/kg] and subsequently sodium fluorescein [20 mg/kg]) was performed with a full-spectrum camera and camera adapter system. Group findings were compared, and multiple linear regression analysis was performed to identify potential factor associations with IVAs. RESULTS: During anterior segment angiography, the arterial, capillary, and venous phases were identified in all dogs. Times to onset of all phases in diabetic dogs were significantly less than those in control dogs. Vascular disruptions within the peripupillary region (evident following sodium fluorescein administration) were common in diabetic dogs. Severity of dye leakage into the iris stroma and aqueous humor was significantly greater in diabetic dogs than in control dogs. Duration of disease, mean blood glucose concentration, and serum fructosamine concentration were significantly associated with IVAs. CONCLUSIONS AND CLINICAL RELEVANCE: In diabetic dogs, anterior segment angiography revealed IVAs that were not evident in control dogs. The severity of those changes appeared to be associated with disease duration and blood glucose regulation.

Prevalence, distribution, and risk factors for canine blastomycosis in Michigan, USA.

Blastomycosis is a systemic fungal infection that most commonly affects dogs and humans. The disease is thought to be endemic in southern regions of Michigan, USA, but epidemiologic investigations have not been reported in detail for this state. The primary aims of this study were to investigate the prevalence and distribution of canine blastomycosis cases in Michigan and to identify risk factors for infection. Over 200 primary care veterinary clinics throughout the state were surveyed regarding blastomycosis prevalence, and demographic information was obtained from medical records of affected dogs that were evaluated at these clinics. A retrospective case control study was conducted for an additional 49 dogs with blastomycosis that were evaluated at specialty referral centers located in the southern mid-Michigan region. Prevalence rates were calculated for each county, and cases were mapped using geocoding software. Univariable and multivariable analyses were used to identify risk factors for infection. Prevalence rates were ≥100 cases per 100,000 dogs in five counties. Most blastomycosis cases originated from the Upper Peninsula or from a high-density area in the northern Lower Peninsula. Multivariable regression analysis identified travel or residence north of the 45th parallel as a strong risk factor for infection (P < .001). Blastomycosis was uncommon in southern counties. These results refute previous speculations and should be of value to both human and animal health. Given that many heightened risk areas are popular tourist destinations, practitioners across the USA should be mindful of the spatial distribution of blastomycosis in Michigan.

Death of Military Working Dogs Due to Bartonella vinsonii Subspecies berkhoffii Genotype III Endocarditis and Myocarditis.

OBJECTIVES: As a result of extensive field-related activities, military working dogs (MWDs) have an increased occupational risk for acquiring vector-borne infectious diseases. METHODS: Indirect fluorescent antibody, Bartonella alpha-proteobacteria growth medium enrichment culture, and 16-23S Bartonella intergenic transcribed spacer polymerase chain reaction were performed using blood, serum, or tissue specimens. RESULTS: Endocarditis was diagnosed in three MWDs infected with Bartonella vinsonii subspecies (subsp.) berkhoffii genotype III. One dog was also infected with Bartonella rochalimae. CONCLUSIONS: B. vinsonii subsp. berkhoffii genotype III may represent an occupational risk for MWDs that develop endocarditis or myocarditis. Comprehensive periodic screening for canine vector-borne infections, in particular occult infections caused by Bartonella spp, is prudent to avoid serious or life-threating illnesses.

Experimental feeding of Hydrilla verticillata colonized by stigonematales cyanobacteria induces vacuolar myelinopathy in painted turtles (Chrysemys picta).

Vacuolar myelinopathy (VM) is a neurologic disease primarily found in birds that occurs when wildlife ingest submerged aquatic vegetation colonized by an uncharacterized toxin-producing cyanobacterium (hereafter "UCB" for "uncharacterized cyanobacterium"). Turtles are among the closest extant relatives of birds and many species directly and/or indirectly consume aquatic vegetation. However, it is unknown whether turtles can develop VM. We conducted a feeding trial to determine whether painted turtles (Chrysemys picta) would develop VM after feeding on Hydrilla (Hydrilla verticillata), colonized by the UCB (Hydrilla is the most common "host" of UCB). We hypothesized turtles fed Hydrilla colonized by the UCB would exhibit neurologic impairment and vacuolation of nervous tissues, whereas turtles fed Hydrilla free of the UCB would not. The ability of Hydrilla colonized by the UCB to cause VM (hereafter, "toxicity") was verified by feeding it to domestic chickens (Gallus gallus domesticus) or necropsy of field collected American coots (Fulica americana) captured at the site of Hydrilla collections. We randomly assigned ten wild-caught turtles into toxic or non-toxic Hydrilla feeding groups and delivered the diets for up to 97 days. Between days 82 and 89, all turtles fed toxic Hydrilla displayed physical and/or neurologic impairment. Histologic examination of the brain and spinal cord revealed vacuolations in all treatment turtles. None of the control turtles exhibited neurologic impairment or had detectable brain or spinal cord vacuolations. This is the first evidence that freshwater turtles can become neurologically impaired and develop vacuolations after consuming toxic Hydrilla colonized with the UCB. The southeastern United States, where outbreaks of VM occur regularly and where vegetation colonized by the UCB is common, is also a global hotspot of freshwater turtle diversity. Our results suggest that further investigations into the effect of the putative UCB toxin on wild turtles in situ are warranted.