Anti-Canine Heartworm monoclonal antibody

Canine and feline heartworm disease caused by Dirofilaria immitis is a serious and sometimes fatal infection transmitted by mosquitos. Little is known about the prevalence or distribution of D. immitis infection in dogs and cats on the island of Hainan island/province or coastal cities of China. The present study examined the occurrence of D. immitis infections in dogs (n = 869) and cats (n = 51) in Hainan island/province and prevalence in dogs from 3 coastal cities (Shenzhen [n = 55], Shanghai [n = 69], and Hangzhou [n = 45]) in southern and eastern China. A commercial antigen detection (AD) test and 2 PCR methods (16S ribosomal RNA and Wolbachia surface protein [WSP] genes) were used to determine the prevalence of D. immitis from animals >6 mo old with no previous history of D. immitis preventive treatment or heartworm infection. Gene sequencing was used to confirm positive PCR samples. The AD test was not used on cat samples. Using the AD test, the prevalence in dogs was 0.5% (4/869) in Hainan island/province, 0% (0/55) in Shenzhen, 1.5% (1/69) in Shanghai, and 0% (0/45) in Hangzhou. Prevalence by 16S rRNA gene PCR was 7.4% (64/869) of dogs from Hainan island/province, 0% (0/55) in dogs from Shenzhen, 1.5% (1/69) in dogs from Shanghai, and 0% (0/45) in dogs from Hangzhou. Prevalence by WSP gene PCR in dogs was 5.3% (46/869) in Hainan island/province, 0% (0/55) in Shenzhen, 1.5% (1/69) in Shanghai, and 0% (0/45) in Hangzhou. Prevalence in the 51 cats from Hainan island/province was 9.8% and 5.9% by 16S rRNA and WSP gene PCR, respectively. The present study demonstrates that canine heartworm exposure occurs in dogs and cats in Hainan island/province and that PCR methods detected a higher prevalence than did the AD method. The 16S rRNA gene PCR detected more positive samples than did the WSP gene PCR in both dogs and cats. The 3 coastal cities had very few dogs that had evidence of D. immitis exposure.

Background: Canine heartworm infections were frequently diagnosed in Brazil before the new millennium. After the year 2000, the frequency of diagnosis showed a sharp decline; however, a few years later, new evidence indicated that the parasite was still present and that canine infection rates seemed to be increasing. Therefore, an updated survey of canine heartworm prevalence was conducted in several locations in south, southeast, and northeast Brazil. Methods: Dogs from 15 locations having previously reported a high prevalence of heartworm infection were included in the survey according to defined criteria, including the absence of treatment with a macrocyclic lactone for at least 1 year. Blood samples from 1531 dogs were evaluated by an in-clinic immunochromatography test kit (Witness (R) Heartworm, Zoetis, USA) for detection of Dirofilaria immitis antigen. At each location, epidemiologic data, including physical characteristics and clinical signs reported by owners or observed by veterinarians, were recorded on prepared forms for tabulation of results by location, clinical signs, and physical characteristics. Results: The overall prevalence of canine heartworm infection was 23.1%, with evidence of heartworm-infected dogs detected in all 15 locations studied. There was a tendency for higher prevalence rates in environmentally protected areas, despite some locations having less-than-ideal environmental temperatures for survival of vector mosquitoes. Among physical characteristics, it was noted that dogs with predominantly white hair coats and residing in areas with a high (>= 20%) prevalence of heartworm were less likely to have heartworm infection detected by a commercial heartworm antigen test kit than were dogs with other coat colors. In general, dogs older than 2 years were more frequently positive for D. immitis antigen than were younger dogs. Clinical signs of heartworm infections were rare or owners were unable to detect them, and could not be used for reliable prediction of the presence of heartworm. Conclusions: These results indicate that the prevalence of D. immitis has increased in these areas of Brazil over the past few years. Small animal practitioners in these areas should include routine screening tests for heartworm infections in every dog's annual evaluation protocol and make sure to have uninfected dogs on prevention.