• 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.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.

• 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.

• Proceedings of the Korean Society of Veterinary Service Conference
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• 1996.05a
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• pp.83.2-84
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• 1996

• 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.16 no.2
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• pp.506-508
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• 1999

An one-year-old, female pointer dog with conjunctival hyperemia, corneal opaque and ocular pain in right eye was referred to Veterinary Medical Teaching Hospital, Chungbuk National University. In the ophthalmic examination the worm was observed in anterior chamber, The heart worm antigen test was positive. A modified Knott's test was negative. The values of complete blood count and serum chemistry (TP, BUN, creatinine, AST, ALT, ALP, albumin, globuline) showed normal ranges. Any abnormality was not detected in the heart using a thoracic radiography and cardiac sonography. Therefore, this dog was diagnosed as ocular filariasis. The worm was removed by surgical incision through a limbus of cornea. The closure of limbal incision was sutured in a simple interrupted suture pattern with 6-0 silk and the eye was reinflated with sterile saline solution. Antibiotics and dexamethasone ophthalmic solution were applied to right eye every 24 hours for 7 days. To prevent latent filariasis, ivermectin was also administered on day 14 of operation. The heart worm antigen test on day 60 was negative. The dog was successfully cured.

• 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 Research
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• v.42 no.4
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• pp.545-550
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• 2002

The raccoon dog (Nyctereutes procyonoides) may be infected by Dirofilaria immitis. However, there has been no report on dirofilarial infection in the raccoon dog in Korea. In this study, we report on D. immitis infection in two wild raccoon dogs captured in the Daejeon area. The two raccoon dogs were referred to the Veterinary Teaching Hospital, Chungnam National University for diagnosis of D. immitis infection. The modified Knott's test for the detection of blood D. immitis microfilariae was positive, and serological test (FASTest$^{(R)}$ HW Antigen ELISA kit, Diagnostik Mega Cor, Austria) for D. immitis was positive as well. Additionally, D. immitis microfilariae were differentiated from other microfilariae by using acid phrnphatase histochemical staining (Leucognost-SP$^{(R)}$kit, Diagncstica MERCK, Germany). The two raccoon dogs were necropsed and D. immitis infection was confirmed.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.171-173
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• 2008

A 3-yr-old female mongrel dog was referred to the Veterinary Teaching Hospital of Chungnam National University in the Republic of Korea. An adult heartworm, Dirofilaria immitis, was found in the abdominal cavity of the dog during spaying. Dirofilariasis in this dog was also diagnosed by modified Knott's test, ELISA test, and PCR analysis. The present case is the first report on the migration of an adult dog heartworm to the abdominal cavity of a dog in the Republic of Korea.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.130-133
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• 2009

The use of screening tests as part of a diagnostic work-up is common in domestic canine practice, but understanding of the diagnostic test characteristics and factors affecting diagnostic accuracy is not clear among clinicians. This article was aimed to provide clinicians with a better understanding on the selection of test kits and with a proper interpretation of test results using an example from heartworm(Dirofilaria immitis) studies. From the literatures, diagnostic accuracy varied depending on the kits: percent average sensitivity and specificity of ELISA antigen-detecting kits were DiroChek(Synbiotics, USA) 78.1 and 95.2, SNAP(IDEXX, USA) 66.3 and 98.1, and Solo Step(Heska, Switzerland) 69.5 and 97.5, respectively, while the values for three hematological methods(Modified Knott's, direct smear and capillary tube) ranged from 38.4 to 81.8% and from 96.9 to 100%, respectively. Furthermore, it was also reported that the prevalence of heartworm disease in domestic dog populations varied depending on the regions studied: 2.5-22.8% for microfilarial test and 2.2-66.3% by ELISA. The values of predictive values for positive(PPV) and negative(NPV) provide useful information to clinicians on the probability of heartworm infection, but the PPV and NPV are greatly dependent on the heartworm prevalence. This suggests that PPV or NPV values of a test should be interpreted carefully in different clinical settings. Practical methods on the interpretation taking into account heartworm prevalence were discussed.