• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.517-520
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• 2003

Prevalence of microfilariae, Dirofilaria immitis, Dirofilaria repens, Acanthocheilonema dracunculoides from 506 German Shepherd dogs reared in Korea was investigated by modified Knott's test to detect circulating microfilaria and by acid-phosphatase staining for differentiation of each microfilaria species. In the modified Knott's test, 74 of 506 dogs (14.6%) were microfilaria positive, and the prevelance of each species of microfilaria was 90.5% (67 of 74 samples) for D. immitis, 5.4% (4 of 74 samples) for duplicate infection with D. immitis and D. repens and 4.1% (3 of 74 samples) for mixed infection with D. immitis, D. repens and A. dracunculoides. It was considered that the paying attention to the existence not only D. immitis but also other microfilariae were needed in canine filariasis.

• 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.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.

• 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.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%).

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.225-232
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• 1996

A survey of canine heartworm (nirofilaria inmitis) infections among German shepherds in five areas of South Korea was performed from October 1994 to August 1995 using a microfilarial test (modified Knott's test) and an antigen test (DiroCHEKⓑ Synbiotics, USA). The infection rate of 127 German shepherds (71 males and 56 females) was 10.2% (13/127) by the microfilarial test, but was 28.3% (36/127) by the antigen test, revealing that 24 of the 36 antigen-positive dogs were microfilaria-negative in the peripheral blood . All dogs that were microfilaria-positive were also antigen-positive. Three of the microfilaria-negative and antigen-positive dogs contained 4-15 adult heartworms in the heart and pulmonary arteries upon necropsy. The infection rate among German shepherds was the highest in Hoengsong-gun (Kangwon-do, 84.4%) , while those of Yechon-gun (Kyongsangbuk-do) and Chungwon-gun (Chungchongbuk-do) areas were 20.0% and 14.3%, respectively. None of the dogs in the Kimhae-shi (Kyongsangnam-do) and Kwangiu areas was heartworm positive. The infection rates of heartworm in dogs at the age of 1-3, 4-6. and 7-11 years were 6.3%, 21.4%, and 56.4%, respectively. Based on the fact that the antigen test is more accurate than the microfilarial test, this study strongly indicates that the prevalence rate of canine heartworm in Korea may be higher than previously reported (3.1-23.0%) which utilized microfilarial tests.

• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.19-26
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• 2003

This study was attempted to survey on the prevalence of canine heartworm(Dirofilaria immitis) infection among 100 dogs(male 39, female 61) on the nine breeding farms in eastern Chungnam province in December 2002. Blood samples taken from dogs were examined for the presence of D immitis microfilaria by the modified Knott's test and an antigen test was using FASTest$\^$/ HW Antigne kit (Mega Cor A-6912 Horbranz-Austraia). 1. Eleven(11.0%) of the 100 examined dogs were microfilaria positive, while nineteen dogs(19.0%) were antigen positive, which suggested that the antigen test was more sensitive than the microfilarial test in detecting heartworm infection. 2. Infected dogs were observed higher more at 2 years older ages(4/48, 8.3%) and male(9/39, 23.1%) than young ages(4/48, 8.3%) and female(10/61, 16.4%). 3. The regional infection rates were of Gongju(15/43, 34.9%), Geumsan(4.27, 14.8%), while none of infection dogs in Yeongi(0/30, 0%). 4. Survey for hematological values of D immitis infected dogs : WBC and eosinophils were 21.4${\pm}$7.2 k/${\mu}\ell$, 3.5${\pm}$0.4 k/${\mu}\ell$, respectively. In conculsion, this study could be overemphasized the importance of control program the heartworm in eastern Chungnam province

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.79-83
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• 2001

Dirofilaria immitis parasitizes mainly in the pulmonary arteries and in the heart of dogs and cats. The parasite is also of public health importance, because it often elicits nodules in the pulmonary parenchyma and in the subcutaneous tissues, or sometimes parasitize itself in the eyes of human. In this study, we investigated the prevalence of heartworm infection among 165 dogs on three breeding farms in the vicinity of Seoul, Korea. Of 165 dogs, 83 dogs (50.3%) were infected with the parasite, as revealed by an antigen-detecting test using the peripheral blood. Of these, 23 dogs (20.2%) contained microfilaria using the peripheral blood, which are potential source of transmission to uninfected animals and to humans in the endemic area. None of infected dogs showed any clinical signs associated with the disease. Since the three farms were located in the vicinity of Seoul, the unexpectedly high infection rate could imply that the possibility of exposure of both animals and humans living in the metropolitan Seoul area to the parasite is higher than in the other area of Korea.

• 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.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.311-316
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• 2009

The purpose of this meta-analysis was to collect data from the literatures reporting prevalence of canine heartworm (HW) infection in an effort to emphasize the preventive importance of the disease and to serve as baseline data for further studies related to the disease management. Fourteen studies regarding the prevalence of HW infection published during the 1996-2007 were identified using the meta-analytic approach, involving a total of 1,790 cases by microfilarial test and 3,277 cases by enzyme-linked immunosorbent assay (ELISA) antigen test for adult worms. Data analysis was performed separately for pet and military dogs. The overall apparent prevalence of HW infection in pet dogs by microfilarial test and ELISA was 11.7% (183/1,563) and 16.5% (379/2,302), respectively (p < 0.001). No significant difference in prevalence by microfilaria and ELISA was observed between sexes whether assessed by data separately or pooled together. Compared to before 2000, the prevalence by microfilaria after 2000 has increased from 2.5% to 13.1% (p < 0.001), and the rate of adult worm has also increased from 9.9% to 20.3% (p < 0.001). The prevalence determined by ELISA was found to increase with age: 20.7% (n = 1,003) of dogs older than 2 years were positive, compared with 5.0% of dogs (n = 701) under 2 years of age (p < 0.001). Also, outdoor dogs showed significantly higher prevalence than indoor dogs (37.9% versus 3.4%; p < 0.001). For military dogs, the overall prevalence was 38.3% (87/227; 95% CI, 32.1 - 44.7%) by microfilarial test and 38.5% (375/975; 95% CI, 35.4 - 41.6%) by ELISA. This rate was significantly higher than that of pet dogs (p < 0.001). Occult infection rate of 37.5% and 66.7% was found in pet and military dogs, respectively.