• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.729-739
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• 2000

Echocardiography, vital signs, microfilaremia, and blood chemistry of 12 Jindo dogs naturally infected with canine heartworms (Dirofilaria immitis) were analysed and compared with those of 5 uninfected control Jindo dogs. Nine of the twelve infected dogs contained microfiaria in the peripheral blood, whereas the presence of adult heartworms in the pulmonary arteries and/or in the heart was detected from four dogs by echocardiography. Among the four echocardiography-positive dogs, two dogs also displayed evidence of heartworms in the right ventricle by echocardiography. Upon necropsy, a total of 547 adult worms was collected from the 12 infected dogs (av = 45.6, range = 9-166). Dogs with positive echocardiograpic images of heartworms contained 48, 74, 104 and 166 adult worms in the heart, pulmonary arteries and/or in the caudal vena cava (av. 98.0), whereas 9 to 39 worms (av. 19.4) were collected from those organs of dogs with negative echocardiography. Most heartworms were found in the right ventricle (438, 80%) at necropsy, whereas relatively fewer worms were found in the pulmonary arteries (96, 17.6%), and in the caudal vena cava (13, 2.4%). The necropsy findings on the location of adult worms significantly differed from the results of echocardiographic analysis in which the right ventricle of most dogs did not show the presence of heartworms. These results indicated that the adult heartworms had been located in the terminal branches of the pulmonary arteries when the host was alive, but the worms moved toward the right ventricle shortly after the heart of the infected dogs stopped beating. Microfilaremia in the peripheral blood was the highest in the blood samples collected at 10 pm. However, the correlation between the number of microfilaria and of adult worms was not observed. Clinical and vital signs of infected dogs did not show any significant difference before and after a 30 minute-exercise at 5 km/hr compared to those of uninfected control dogs.

• Journal of Veterinary Science
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• v.24 no.4
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• pp.46.1-46.12
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• 2023

Background: Heartworm infection in dogs is caused by Dirofilaria immitis and common in shelter animals and outdoors dogs. Caval syndrome can develop with severe infection and physical heartworm removal is essential with heartworm burdens. In this study, we used an improved transvenous heartworm extraction brush, which was expected to cause less cardiovascular damage and allow easier manipulation. Objectives: This study aims to evaluate efficacy of this improved transvenous heartworm extraction brush. Methods: The brush was designed to improve upon the limitations of the previous brush-type devices. The brush was made of a polyvinyl chloride tube and threads of polyamides or polyglyconates. Metal material was inserted at the front tip for easy visualization under fluoroscopy. The eight dogs diagnosed with caval syndrome with large numbers of heartworms and pulmonary hypertension were used in this study. The removal procedure began with the dissection of the subcutaneous tissue around the right jugular vein. The device was inserted through the jugular vein. After insertion, the tube was rotated to catch the heartworms and extracted with the heartworms hanging on the threads. The procedure was repeated several times. Lastly, jugular vein and skin sutures were made. Adulticidal therapy was administered after heartworm removal. Results: The mean number of removed heartworms was 10.5 ± 4.24 and mean number of remaining heartworms was 0.63 ± 1.06. Total procedure time was 72.63 ± 51.36. Except for three cases, heartworms were not detected on ultrasonography after the procedure. No procedure-related side effects were observed within the 1- to 2-mon. Conclusions: An improved transvenous heartworm extraction brush is efficient for heartworm removal in dogs with caval syndrome.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.155-164
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• 2007

This study was conducted to investigate the prevalence of canine heartworm infections, canine brucellosis and hematologic values from 153 free roaming dogs in the area of Gwangju city from March to November 2006. Nineteen (12.4%) of 153 samples tested with modified Knott's technique showed positive reaction for microfilariae. Polymerase chain reaction using specific primers for D immitis amplified the expected product from all samples of 19 microfilaremic canine blood samples as determined by the modified Knott's test for microfilariae. The seasonal infection rates of microfilariae were higher in the spring season (10/19, 52.6%) than in the other seasons. The major hematological findings in microfilaremic dogs were mild leukocytosis and mild monocytosis. A total of 100 dogs randomly selected from 153 free roaming dogs were negative for canine brucellosis by serological test using immunochromatographic antibody test kit.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.77-81
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• 2007

Diagnostic performance of polymerase chain reaction (PCR) for detecting Dirofilaria immitis in dogs was evaluated when no gold standard test was employed. An enzyme-linked immunosorbent assay test kit (SnapTM, IDEXX, USA) with unknown parameters was also employed. The sensitivity and specificity of the PCR from two-population model were estimated by using both maximum likelihood using expectation-maximization (EM) algorithm and Bayesian method, assuming conditional independence between the two tests. A total of 266 samples, 133 samples in each trial, were randomly retrieved from the heartworm database records during the year 2002-2004 in a university animal hospital. These data originated from the test results of military dogs which were brought for routine medical check-up or testing for heartworm infection. When combined 2 trials, sensitivity and specificity of the PCR was 96.4-96.7% and 97.6-98.8% in EM and 94.4-94.8% and 97.1-98% in Bayesian. There were no statistical differences between estimates. This finding indicates that the PCR assay could be useful screening tool for detecting heartworm antigen in dogs. This study was provided further evidences that Bayesian approach is an alternative approach to draw better inference about the performance of a new diagnostic test in case when either gold test is not available.

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.369-375
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• 2009

This study was attempted to survey the prevalence of heartworm infection among 253 dogs (male 167, female 86) on the 16 breeding farms in southern Gyeongnam area in May to December 2007. The results obtained from this experiment were summarized as follows; Fifty seven (22.5%) of the 253 examined dogs were heartworms-antigen positive, while twenty five dogs were Microfilaria positive by the modified Knott's method. The regional infection rates were of 25% in Tongyeong and 21% in Goseong, and on the breeding environment aspects, infection rates were lower in rural area than urban area farms. The infection rates were higher in female (26/86, 30.2%) than male dog (31/167, 18.6%). The infection rates by breeding size of farms were 31% (11/35) at <20 head, 26%(35/135) at 20~50 head and 13% (11/82) at >50 head. The infection rates of heartworm in examined dogs at the age of <2, 2~4 and >5 were 10.7% (8/75), 26% (40/154) and 37.5% (9/24), respectively. In the microfillaria-infected 25 dogs, identified Dirofilaria immitis of 21 (84%) using PCR. The dogs infected with heartworm showed the increased number of eosinophil.

• Korean Journal of Veterinary Service
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• v.42 no.3
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• pp.145-152
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• 2019

Canine vector-borne diseases (CVBDs) are transmitted by different groups of hematophagous arthropod vectors that are distributed worldwide and can cause significant health problems for dogs. The aim of this study was to investigate and compare the prevalence of selected CVBD pathogens in rural outdoor dogs based on prevention status. Between June 2017 and February 2019, blood samples were collected from 343 clinically healthy rural dogs composing two different groups: systematically managed dogs (SMD; n=92) and personally managed dogs (PMD; n=251). Vaccination and preventive medications were applied strictly following the programmed schedule for the SMD group; in contrast, in the PMD group, they were applied only when requested by the dog owners. Serological and molecular assessments showed that significantly more dogs in the PMD group were infected with B. gibsoni (P<0.001) and D. immitis (P=0.001) than those in the SMD group. These findings suggest that the regular use of preventive medications and environmental controlling efforts contribute to reducing the prevalence of CVBD pathogen infections. In addition, dogs infected with certain kinds of CVBD pathogens could remain asymptomatic, suggesting that continuous monitoring and periodic preventive treatment should be conducted even for clinically healthy dogs.

• Korean Journal of Veterinary Research
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• v.60 no.1
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• pp.15-18
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• 2020

Canine heartworm disease is a vector-borne disease that is transmitted from dog to dog by mosquitoes. It causes epidemics that disrupt the health environments of dogs and are burdensome for many dog owners. Recent trends of changing temperatures and weather conditions in South Korea may have an impact on the population of mosquitoes, and it affects the population of dogs at risk of heartworm infection. Mathematical modeling has become an important measure for analyzing the epidemiological characteristics of infectious diseases. However, canine heartworm infection transmission has not been reported yet through mathematical modeling. We develop a mathematical model of canine heartworm infection to predict the population of infected dogs depending on the vector (mosquito) population using a susceptible, exposed, infected, and recovered model. Simulation results show that after 1 year, 3,289 dogs out of 73,602 (about 4.5%) are exposed and 134 (about 0.2%) are infected. Only 0.2% of susceptible dogs become infected after 1 year. However, if all exposed dogs are maintained in the same circumstances without any treatment, then the number of infected subjects will increase over time. This may increase the possibility of other dogs, especially dogs that live outside, being infected.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.42-45
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• 2019

Thromboelastography (TEG) analysis consists of ${\alpha}$, G, K, MA, and R types of values and tests the effectiveness of blood clotting, which can be assessed for platelet function, clotting strength, and fibrinolysis. Canine heartworm diseases caused by Dirofilaria immitis, a vascular nematode, can lead to hyperfibrinolysis and hypercoagulation. In this study, G and MA values showed a statistically significant decrease over time after treatment of heartworm disease. Additionally, the ${\alpha}-value$ showed a high correlation with G, K, MA, and R values. The G value showed a high correlation with K and MA values, while The K value showed a high correlation with MA and R values. This study clearly found a gradual decrease in G and MA values in dogs with heartworm disease over time, both before and after treatment. This suggests that the clot formation time is longer and that the intensity of clot formation is lowered and may improve the risk of thromboembolism in dogs with heartworm disease.

• Journal of Veterinary Clinics
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• v.34 no.1
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• pp.1-6
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• 2017

Heartworm disease (HWD) in dogs is a life-threatening mosquito-borne disease resulting in right-sided congestive heart failure and inflammatory pulmonary disease. Due to complications from adulticidal therapy with melarsomine, slow kill protocol either with preventive dose of ivermectin or combined with doxycycline has been proposed for an alternative adultcidal therapy in dogs with HWD. Therefore, this study evaluated the clinical outcome of adultcidal therapy in dogs with class II stage of HWD after treating either American Heartworm Society (AHS) or slow kill protocol for 10 months. Clinical outcome after therapy was evaluated by clinical, radiographic and echocardiographic examination along with hematology before (D0) and after therapy (D300). Although clinical signs associated with HWD were all resolved after therapy in both groups, the infection was not cleared out 67% of dogs treated by slow kill protocol at the end of therapy. Furthermore, pulmonary arterial flow of acceleration time to ejection time ratio (AT/ET) and the right pulmonary artery distensibility index (RPADI) have been firstly used for detecting pulmonary hypertension in this study group. The pulmonary hypertension was more common in dogs with mild clinical signs, although tricuspid and pulmonary regurgitation were not detectable in most dogs in this study. Our study findings suggested that the slow kill protocol might not be efficacious enough to clear out HWD in dogs and more attention on the presence of pulmonary hypertension might be necessary for effective management of HWD in dogs.

• Journal of Veterinary Clinics
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• v.38 no.3
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• pp.152-158
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• 2021

A 3-year-old spayed female beagle dog was presented with epiphora, severe hemorrhagic and purulent ocular discharge in the right eye (OD). A reflux of the discharge through the other canaliculi, associated with signs of chronic inflammation, was observed on cytology. Dacryocystorhinography revealed retention of contrast media ventral to the lower punctum, indicating complete obstruction and the potential presence of radiolucent foreign body. Ocular discharge subsided after the first treatment, including flushing of the nasolacrimal duct and application of topical antibiotics and corticosteroids, but clinical symptoms of the dacryocystitis waxed and waned thereafter. Surgical treatment was delayed for 8 months due to Dirofilaria immitis infection, and topical treatment and monthly flushing were maintained. On the day of operation, a foreign body was released through the fistula, while flushing for disinfection under general anesthesia, just before the surgery. Dacryocystectomy was performed to remove necrotic tissue and residual foreign body around the nasolacrimal cyst. Upon histopathologic findings, the removed foreign body was considered to be a plant, and the nasolacrimal cyst was comprised of chronic active ulcerative inflammation and necrotic tissues. At the 1-week recheck, improvement of epiphora and ocular discharge and healing of the surgical site was noted. In conclusion, nasolacrimal duct foreign body can be considered in recurrent dacryocystitis, despite nasolacrimal flushing and topical medication. In this study, dacryocystectomy was curative without recurrence of dacryocystitis or epiphora.