• 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.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.327-332
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• 2013

A survey of canine heartworm (Dirofilaria immitis) infection among 102 Jindo dogs was performed from September to October 1995, using a microfilarial test (modified Knott's test) and an antigen test (DiroCHEK, Synbiotics, USA). The infection rate of 102 Jindo dogs was 1.9% (2/102) by the modified Knott's test, but was 4.9% (5/102) by the antigen test. This result revealed that the antigen test is more accurate than the microfilarial test. Also, 222 Jindo dogs (Male 61, Female 161) were examined for Dirofilaria immitis infection from 1995 to 1997 using an antigen test (DiroCHEK, Synbiotics, USA). Twelve (5.4%) Jindo dogs were positive for Dirofilaria immitis antigen. The infection rates were higher than in male (6.6%, 4/61) than female dogs (5.0%, 8/161). The infection rates of heartworm in Jindo dogs at the age of under 1 year, 1~2 years and over 2 years old were 0.0% (0/39), 4.3% (5/115) and 10.3% (7/68), respectively. The older age had higher infection rates than the younger age (P=0.018). The infection rates of canine heartworm was reported to be the highest (17.6%, P=0.028) in Jodo-myeon, 10.6% in Uisin-myeon and 5.3% in limhoe-myun. But dogs with antigenemia weren't detected in Gogun-myeon. and Jisan-myeon. This study indicates that the prevalence of canine heartworm in Jindo-gun is lower than previously reported (3.1% and 12.3%) which utilized microfilarial tests.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.130-137
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• 2000

In order to diagnose canine heartworm infection by antigen capture ELISA, the crude somatic(S), partial somatic(below 45kDa) and excretory/secretory(E/S) antigen of adult heartworm were identified and the antigenicity was examined by silver stain, immunoblot and ELISA. Then, production of monoclonal antibody to specific antigen carried out in this experiment. The bands to S antigen and E/S antigen were recognized between 10 and 200kDa and common bands were recognized strongly 14, 18, 28, 43kDa by silver stain. By western blot analysis, fractions to S antigen were recognized 14, 16, 18, 20, 24, 28, 32, 43, 50, 55kDa, etc. and only a 14kDa to E/S antigen in positive sera which were positive in modified Knott's test and necropsy. In ELISA, the positive sera reacted to antigens(SA, $SA_{45}$, E/S) were significantly different from negative sera by Student's t-test(p<0.05). Four hybridoma cell lines(14, 16, 17, 32kDa) than produce specific monoclonal antibodies for these antigens were obtained by immunizing BALB/c mice with a partially purified somatic antigen (below 45kDa) preparation, by fusing spleen cells with SP2/O cell myeloma cells, and by screening cell culture supernatants for antibody. In these results, it was confirmed that partial somatic antigen(below 45kDa) or E/S antigen can be used for serologic diagnosis of heartworm infection and monoclonal antibody reacting with specific antigen(14kDa) can be used for antigen capture ELISA in prepatent period of canine heartworm infection.

• Korean Journal of Veterinary Service
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• v.20 no.1
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• pp.47-53
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• 1997

We have investigated the prevalence of canine heartworm (Dirofilaria immitis) infection among 100 mixed-breed dogs raised in Chonnam Province (Koheung, Posung, Changheung, and Hwasoon) and 100 dogs randomly selected from visiting dogs to the College of Veterinary Medicine, Chonnam National University for routine physical examination. Blood samples taken from dogs were examined for the presence of Dirofilaria immitis microfilaria by the modified Knott's test, and an antigen test which was based on the sandwich ELISA(DiroCHEK(equation omitted), Synbiotics, Inc., San Diego, California, USA) was used to detect the adult heartworm-specific antigen from serum samples. The results were then compared with those of the modified Knott's test. Five(2.5%) of the 200 examined dogs were microfilaria-positive, while 8 dogs(4%) were anti-gen-positive, which suggested that the antigen test was more sensitive than the microfilarial test in detecting heartworm infection. All dogs that were microfilaria-positive were also antigen-positive. The place of origin of the heartworm-positive dogs were of Naju (4/26, 15.4%), Koheung(3/32, 9.4%), and Hwasoon (1/19, 5.3%), while none of dogs raised in Kwangju, Posung, and Changheung areas were infected with the parasite. Although not significant, more infected dogs were observed in older ages, while the difference in infection rate between male (4/98, 4.1%) and female (4/102, 3.9%) was not recognized. Our results indicated that a relatively low infection rate was observed in dogs raised in Kwangju and Chonnam area compared to the infection rate reported previously in other areas of South Korea.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.347-351
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• 2015

A 3-year-old intact female Dachshund was referred due to paraplegia and cool extremities. History taking, physical examination, neurological examination, and blood profiling studies were evaluated to determine the diagnosis. Based on abdominal ultrasound and echocardiograph, features suggestive of adult heartworm were detected in aberrant places. The result of enzyme-linked immunosorbent assay (ELISA) testing with a commercial heartworm antigen kit was positive. The dog fell into a comatose state, and the client requested the dog be euthanized. On post-mortem examination, the patient was diagnosed with ectopic parasitism of heartworm in the left side of heart, aorta, aorta abdominalis, and iliac arteries, a circumstance that induced systemic thromboembolism. This case report describes the clinical, diagnostic imaging, and necropsy findings of canine ectopic parasitism of heartworm.

• Korean Journal of Veterinary Service
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• v.26 no.2
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• pp.129-134
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• 2003

A survey of canine heartworm(Dirofilaria immitis) infections among dogs in Daefu area was performed from February 2000 to October 2002 using a microfilarial test and an antigen test(AGEN$^{TM}$ Canine heartworm). The infection rate of 220 dogs(96 males, 124 females) was 23.2%(51/22) by the microfilarial test, but was 23.6%(52/220) by the antigen test, revealing that 1 of 52 antigen-positive dogs were microfilaria-negative in the peripheral blood. All dogs that were microgilaria-positive were also antigen-positive. The infection rates of heartworm in dogs at the age of < 1, 1-3, 4-6, 7-11 and 12-15 years were 2.7%, 17.4%, 41.0%, 42.9% and 57.1%, respectively. Based on the fact that the antigen test is more accurate than the microfilaria test. The infection rates of heartworm in dogs by housing of indoor and outdoor were 6.9% and 46.4%, respectively. Based on the fact that outdoor housing is more infectious than indoor housing.

• 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%).

• 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.

• Korean Journal of Veterinary Service
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• v.33 no.2
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• pp.157-165
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• 2010

A survey of canine heartworm infections among 83 dogs (Male 42, Female 41) of pet dogs in Ulsan area was performed from March to July 2009 using antigen test. Of 83 dogs, 6 dogs (7.2%) were infected with the Dirofilaria immitis, and 5 dogs (6%) were detected to have microfilaria in the peripheral blood. The infection according to the age of 4~5, 6~7, 7 over years were 7.4%, 12.5%, and 10.5%, Also, A survey of canine heartworm infections among 23 dogs (Male 15, Female 8) of hunting dogs in Ulsan area was performed from July 2008 using antigen test. Of 23 dogs, 11 dogs (47.8%) were infected with the D. immitis, and 6 dogs (26.1%) were detected to have microfilaria in the peripheral blood. The infection according to the age of under 1, 2-3, 4-5, 6-7 over years were 12.5%, 40%, 85.7% and 66.7%, respectively.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.25-35
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• 1999

The prevalence of canine heartworm(Dirofilaria immitis) infection in 150 mixed-breed dogs(male : 54, female : 96) from February to December 1997 was investigated by using antigen test kit(ICT $GOLD^{TM}$ HW, Synbiotics, USA) based on immunochromatographic assay in Inchon city. Also, gross and histopathological findings of an antigen positive dog were carried out. The results were summarized as follows ; 1. Four dogs were positive from 150 tested dogs(2.7%). They were all more than 2 years old and infection rates in male and outdoor dogs was higher than those in female and indoor, respectively. Species of infected dogs were Pug(2) , German Sheperd(1) and Great-dane (1). 2. Regional infection rates were closely related with housing system in the city. 3. Pathological findings of antigen-positive dog was excessive enlargement, congestion and hemorrhage of lung and D immitis in heart and histologically hemosiderin, hypertrophy of pulmonary alveoli wall and irregular hypertrophy of pulmonary artery inner wall. Microfilaria was observed in pulmonary artery and arteriole, ventricle and splenic artery.