Epidemiological Survey of Dirofilariasis of Stray Dogs in Taichung Area and Blood Parasites Infection of Housed Dogs in Kimmen Area and The in Vitro Lysis of Canine Heartworm by Use of Bromelain

• Main Authors: Tsai I-Da, 蔡依達
• Other Authors: Cheng Feng-Pang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/61848350492847554410

碩士 === 國立中興大學 === 獸醫學系 === 90 === The aim of this study was to investigate the effect of bromelain on the lysis of canine adult heartworm body. Three concentrations (1 mg/mL, 5 mg/mL and 10 mg/mL) of bromelain were respectively prepared in two millipore-filtered (0.45 µm) mediums (plasma, and PBS). Adult heartworms were rinsed with sterilized distilled water, killed by incubation of 0.1 µg/ml RM340® （Melarsomine dichlorhydrate）for 24 hours then incubated in prepared mediums at 37°C for up to 2 months. Mediums were refreshed every 3 days till the completion of heartworm lysis. Male and female adult heartworms were separately tested according to their body weight. The adult worm body incubated in 5 mg/mL and 10 mg/mL bromelain mediums were complete dissolved. However, the worms in controls remained intact for two months onward. Bromelain dissolved male and female heartworms in a similar pattern (p>0.05). Bromelain posses more lysis potency in PBS mediums than in plasma. It might be due to plasma proteins reduce bromelain’s dissolve ability. Conclusively, Bromelain is able to dissolve the heartworm in vitro. It suggests that heartworm contains Z-Arg-Arg+NHMec protein structure. The incidence of heartworm disease is gradually increasing in north Taiwan since 1993. This study was carried out to survey the prevalence of Dirofilaria immitis infection in stray dogs inhibited in Taichung area in August 2000 to December 2001. A total number of 82 necropsy (47 males and 35 females) was investigated. Nearly 54 % (44/82) was found with heartworm inhabited in the pulmonary artery and/or the right ventricle. The respective percent of the heartworm infection was 59.5 % (28/47) in the male dogs and 45.7 % (16/35) in the female. Only 53.6 % (28/44) of infected dogs was microscopically examined to be microfilaria positive by using direct smear technique. The length of male and female heartworms was 15.8±2.1 cm and 27.1±3.2 cm (n=100), respectively. The weight of male and female heartworms was 0.06±0.01 g and 0.15±0.02 g (n=100), respectively. Number of heartworm inhabitant was ranged from 1 to 44. The major infected age-group was those dogs within 4 to 6 years old. Besides, neither the correlation of gender and infection rate (r=0.14, p>0.05) nor the correlation of coat length/color and infection rate (r=0.07, p>0.05) was not detected. The major infected dog breed was the Mongrel. This is well possibly because Mongrel is the most common breed seen on streets. The major infested group in terms of body weight was those dogs with 5 to 15 kilograms. To understand the present status of canine blood parasites infection among housed dogs in Kinmen area, a combined ELISA kit IDEXX (Dirofilaria immitis, Ehrlichia canis, Borrelia burgdorferi) and microscopic examinations of Giemsa’s stained blood smears were conducted in randomly chosen 96 individuals (1,148 total population) in December 2001. The percentage of D. imitis, E. canis and B. burgdorferi seropositive dogs were detected to be 4.2%, 13.5% and 0% respectively and of the infected population, dual infection rate was 2.1%. Blood smear examinations revealed 12.5% of the dogs with Ehrlichia morula hosted in either monocyte or platelets. Taken together with results of ELISA kits, Ehrlichiasis was 15.6% of whole surveyed population. Infection of Hepatozoon spp. and Babesia spp. were merely observed in two single individual, respectively. Eighty percents of surveyed dogs did not receive any annual vaccine booster, whereas 87% had been immunized with the anti-Rabies vaccines within the past 12 months. Of the surveyed dogs, 10% were sterilized. Conclusively, low incidence of Dirofilariasis and relatively high prevalence of Ehrlichiasis suggest that prompt means of disease control should be undertaken to prevent from potential increasing prevalence.