• Korean Journal of Veterinary Research
• /
• v.60 no.1
• /
• pp.15-18
• /
• 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 the korean veterinary medical association
• /
• v.28 no.6
• /
• pp.344-347
• /
• 1992

This study was performed to investigate the infestation rate of heartworm(Dirofilaria immitis) in the peripheral blood of the dog being raised in Korea. Blood samples were obtained between 17 : 00 and 20 : 00 from June to August, 1991. Heartworm was exami

• Journal of Veterinary Clinics
• /
• v.18 no.1
• /
• pp.85-87
• /
• 2001

A 3-year-old female jaguar (Panthera onca onca) died after having 1 day history of respiratory failure. At necropsy, the pericardial sac contained large amounts of cloudy fluid enriched with fibrin. Numerous yellowish nodules, which are variable in size and often confluent, are randomly scattered throughout the myocardium. Pasteurella haemolytica was isolated from the pericardial sac and myocardium. In the lung, severe pulmonary congestion, edema and vasculities with intralesional presence of heartworm were found. Therefore the cause of death in this jaguar is believed to be due to respiratory failure following concurrent heartworm infection and bacterial pericarditis and myocarditis.

• Journal of Veterinary Clinics
• /
• v.40 no.6
• /
• pp.457-463
• /
• 2023

A 13-year-old neutered male Pomeranian, weighting 3 kg, presented with respiratory distress and depression. Radiographic examination revealed calcified ring-like opacities in the main pulmonary artery, mimicking thoracic foreign bodies. Additionally, right heart and main pulmonary artery enlargement and notable lung infiltrations were also observed. Echocardiography showed coil shaped structures in the main pulmonary artery with increased echogenicity compared to other nearby heartworms, which is consistent with calcified Dirofilaria immitis (heartworms). The dog was diagnosed with caval syndrome, which is the advanced and severe manifestation of heartworm infection. This report presents a rare case of calcified heartworm infection observed during a radiological examination, which resemble foreign bodies. Therefore, chronic heartworm disease should be considered as a differential diagnosis when radiopaque ring-like opacities are observed in the pulmonary artery on thoracic radiographs.

• Korean Journal of Veterinary Service
• /
• v.20 no.1
• /
• pp.47-53
• /
• 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
• /
• v.36 no.4
• /
• pp.327-332
• /
• 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
• /
• v.40 no.1
• /
• pp.130-137
• /
• 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.

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

• Journal of Veterinary Clinics
• /
• v.37 no.6
• /
• pp.311-316
• /
• 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
• /
• v.26 no.2
• /
• pp.130-133
• /
• 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.