• 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.17 no.1
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• pp.194-204
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• 2000

Echocardiography was performed to obtain the optimal planes for diagnosis of canine heartworm disease in 11 dogs. Imaging planes were taken the left ventricular outflow tract long-axis view, 4-chamber long-axis view, chordae tendineae level short-axis view and modified pulmonary arteries level short-axis view in the right parasternal window, and aptical 4-chamber long-axis view in hte left parasternal window. After echocaridography, the pulmonary artery valve pat was ligated with double 1-0 silk under the general anesthesia to prevent heartworm moving from pulmonary artery to right ventricle. The dogs were euthanized and examained for heartworms in heart and great vessels. Many adult heartworms were identified ultrasonographically within main pulmonary artery, bifurcation of pulmonary artery and right pulmonary artery, but not identified within right ventricle and atrium. At necropsy, adult heartworms were mainly found in pulmonary artery in 11 days, and also found in right ventricular outflow tract and right ventricle in 2 of 11 dogs. The modified pulmonary arteries level short-axis view was the best imaging plane for identifiying heartworms because the main pulmonary artery, branches of pulmonary artery and right pulmonary artery could be showed. The aortic root internal dimension (AOID) and right pulmonary atery internal dimension (RPAID) were measured from the modified pulmonary ateries level short-axis view and left ventricular outflow tract long-axis view. The RPAID and RPAID/AOID was higher in heartworm infected dogs than normal Korea Jin-do dogs in modified pulmonary arteries level short-axis view, and the AOID, RPAID and RPIAID/AOID was higher than in left ventricular outflow tract long-axis view, respectively. These results indicate that the pulmonary arteries were the major habitat of adult heartworm in canine heartworm disease and the modified pulmonary arteries level short-axis view was the best imaging planes for identifying heartworms because the main pulmonary arteries could be showed. Therefore the modified pulmonary arteries level short-axis view can be used for diagnosing heartworm disease and for monitoring dilation of pulmonary artery.

• 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 the korean veterinary medical association
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• v.32 no.8
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• pp.495-502
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• 1996

• Journal of the korean veterinary medical association
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• v.42 no.8
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• pp.756-763
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• 2006

• Korean Journal of Veterinary Service
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• v.27 no.2
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• pp.133-137
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• 2004

This study was attempted to survey on the prevalence of canine heartworm(Dirofilaria immitis) infections among 206 dogs (male 92, female 114) in Daejeon area from March to December 2003. Blood samples taken from dogs were examined for the presence of D immitis microfilaria by the modified Knott's test and an antigen test( $AGEN^{TM}$ canine heartworm). The result obtained from this experiment were summarized as follows; 1. Eighteen(8.7%) of the 206 examined dogs were microfilaria positive, while twenty five dogs(12.1%) were antigen test positive. 2. The infection rates of heartworm in dogs at the age of <2, 2∼4 and $\geq$5 were 3.8%, 18% and 25%, respectively. 3. The infection rates of heartworm in dogs by housing of indoor and outdoor were 3.3% and 36.4%, respectively. 4. The regional infection rates were Dong-gu(13/29, 44.8%), Seo-gu(7/92, 7.6%), Yuseong-gu(2/33, 6.1%), Jung-gu(1/17, 5.9%) and Daedeok-gu(2/35, 5.7%). 5. The seasonal infection rates were summer(June∼August, 16.7%), autumn (September∼October, 14%), spring(March∼May, 9.4%) and winter(November∼December. 7.7%).7.7%).

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.233-241
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• 2001

Dirofilaria immitis, the causative agent of canine heartworm disease, inhabits mainly in the pulmonary arteries and the heart of dogs and cats, causing circulatory and respiratory disorders. Although diagnosis of the disease is based on the presence of microfilaria in the peripheral blood or of specific antigens released from the adult worms into the peripheral blood, the severity of the infection and the assessment of disease progression are based on the clinical signs and radiographic image analysis. We analysed 12 mixed-bred Jindo dogs naturally infected with Dirofilaria immitis without any clinical signs and compared the radiographic images of the heart and the lung with the number of adult worms at necropsy. The dorsoventral radiographs of 12 infected dogs revealed that the right caudal lobar pulmonary arteries (RCaLPA) were dialated in 66.7% of dogs, whereas the main pulmonary artery segment was enlarged in 50.3% of dogs. The cranial lobar pulmonary arteries (RCrLPA) were dilated or pruned in 33.3% of dogs. All dogs displayed the interstitial lung pattern, while the vertebral heart size (VHS) was of normal range. Although a range of 9 to 166 adult worms (av. 45.6) was found in the pulmonary arteries, in the heart or in the vena cava, no correlation with the radiographic findings and/or with the clinical signs was observed.

• Korean Journal of Veterinary Service
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• v.41 no.2
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• pp.79-83
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• 2018

This study compared serum concentrations of suppression of tumorigenicity 2 (ST2) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) between healthy and heartworm- infected dogs. Eighteen heartworm-infected dogs and five healthy dogs were included in the study. Dogs were diagnosed and categorized by history, clinical signs, and blood assay, thoracic radiography, echocardiography, and commercial ELISA kit results. Serum samples were sent to the IDEXX reference laboratory for NT-proBNP measurement. ST2 was examined by using a canine interleukin 33 receptor ELISA kit with the quantitative sandwich ELISA method. The severely infected group showed significant elevation of NT-proBNP concentration over those of the control (P=0.03) and mildly infected (P=0.04) group. There were no significant difference in ST2 concentrations among the three groups. The usefulness of NT-proBNP as a cardiac biomarker in dogs with severe heartworm disease was confirmed by the results of this study. Further investigations to assess ST2 as a cardiac biomarker are warranted.

• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.311-316
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• 2020

Biomarkers used in dogs with heartworm disease include N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI), which are associated with damage to the myocardium. Pulmonary hypertension is one of the clinical signs of canine heartworm disease. The purpose of this study is to investigate the change in the concentration of each biomarker, severity of pulmonary hypertension and the correlation between biomarkers according to the severity of clinical signs. Five healthy dogs and 10 heartworm-infected dogs were recruited for the study. The heartworm-infected group was classified based on the history, clinical signs, and blood assay, thoracic radiography, and echocardiography after confirming the infection according to the results of the commercial ELISA kit (SNAP test, IDEXX Laboratories, Maine, USA). NT-proBNP was higher in the severely infected group than the control group (p < 0.05); cTnI was also higher in the severely infected group than the control group (p < 0.05). The pressure gradient of pulmonary hypertension was higher in the severe group than the mild group (p < 0.05). The severity of pulmonary hypertension was correlated with NT-proBNP (r = 0.818, p < 0.01), cTnI (r = 0.894, p < 0.01). When the correlation of the two serum values for each group was examined, a correlation was not found in the mild group (r = 0.707, p = 0.182), but a correlation was found in the severe group (r = 0.9, p < 0.05). NT-proBNP and cTnI were significantly increased and correlated with severe clinical signs. Pulmonary hypertension was significant higher in the severe group than in the mild group (p < 0.05). Evaluation of blood biomarker concentration and severity of pulmonary hypertension and referring to each correlation between these indicators may be helpful to assess the severity of the heartworm disease.

• Journal of Veterinary Clinics
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• v.39 no.4
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• pp.177-184
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• 2022

Caval syndrome is a severe complication of canine heartworm disease in which affected dogs present with various clinical signs that are often life-threatening. In cases of severe infection, adulticidal treatment has numerous complications as a result of a marked immune response against dead worms. Therefore, several surgical and non-surgical methods, including interventional extraction, have been applied in veterinary medicine. Despite the usefulness and efficiency of conventional retrieval devices, a few associated limitations must be addressed to reduce their risks and increase their applicability. Herein, we introduced a case of treating three dogs with caval syndrome by applying a newly developed heartworm basket device. The dogs were diagnosed with heartworm disease by heartworm antigen testing and direct smear. Imaging findings revealed remarkable remodeling of the right heart and pulmonary vessels and the presence of heartworms in the right heart. Additionally, heartworms were confirmed in the distal part of the abdominal aorta and femoral arteries in one dog, indicating aberrant systemic migration of the worms. Under general anesthesia, the heartworm basket device was introduced into the right heart via femoral venotomy and arteriotomy in one dog and jugular venotomy in the other two dogs. Although the number of cases in this study was small, the basket device was successful in gradual and cautious extraction of the heartworms in all three dogs. They exhibited good prognosis of clinical symptoms as indicated by imaging analyses.