Prophylactic effect of milbemycin oxime against Dirofilaria immitis infection in dogs: optimum dose and administration time

Chronic polyarthritis associated to Cercopithifilaria bainae infection in a dog

Despite the widespread distribution of Cercopithifilaria bainae among canine and tick populations worldwide, this filarioid is currently considered of 'minor importance' in veterinary medicine, particularly when compared to related filarioids, such as Dirofilaria immitis and Dirofilaria repens. To date, only a single case of dermatological alterations possibly associated to infection by C. bainae had been reported in a dog. In the present study, we describe the first case of systemic alterations associated to C. bainae infection in a dog suffering from diffused chronic polyarthritis. The animal had a previous history of reluctance to move and stiff gait and displayed multiple joint pain during manipulation of limbs. No biochemical, haematological and X-ray alterations were detected; microfilariae were observed in the synovial fluids collected from the joints. In spite of the morphological and molecular identification of these microfilariae as C. bainae, the dog did not respond to multiple microfilaricidal treatments with milbemicyn oxyme. The potential role of C. bainae in the pathogenesis of this clinical condition is discussed. Given the potential pathogenicity of this parasite, improved knowledge of this little known tick-borne nematode is warranted in order to assist the development of novel and effective treatment strategies.

Comparative palatability of two veterinary dewormers (Milpro(®) and Milbemax(®)): a blinded randomised crossover cat study

Background

The combination of milbemycin oxime–praziquantel is widely used against the most common tapeworms and roundworms affecting cats. New veterinary presentations of this combination have recently been approved.

Objective

The objective of this study was to compare the palatability of two products using this combination, Milpro^® and Milbemax^®.

Methods

In all, 20 adult cats and 20 kittens were offered each product according to a randomisation table using a blinded crossover design. Prehension from the bowl, prehension from the hand and total consumption were assessed.

Results

Both presentations were very well tolerated in adult cats and kittens. Total prehension in adult cats and kittens was 100 and 45 per cent, respectively, for Milpro^®, and 95 and 30 per cent, respectively, for Milbemax^®. The percentages of adult cats and kittens which swallowed the pill after taking it into their mouth (total spontaneous consumption) were respectively 40 and 45 per cent for Milpro^®, and 35 and 20 per cent for Milbemax^®.

Conclusion

In this study, both presentations were highly attractive to cats and their respective coatings successfully covered the unpleasant odour of praziquantel, which usually repels cats. These results indicate that the palatability of Milpro^® is at least as good as Milbemax^® and both tablets are well accepted by adult cats and kittens.

A serological survey of Dirofilaria immitis infection in pet dogs of Busan, Korea, and effects of chemoprophylaxis

The status of Dirofilaria immitis infection was assessed in pet dogs of Busan, Korea, and chemoprophylactic effects of microfilaricidal medication were evaluated. A total of 294 pet dogs older than 6 mo were examined, 217 of which had been maintained indoors, and 77 had been kept outdoors. The SnapR kit and direct microscopic examinations of the peripheral blood were used. The mean overall parasite positive rates were 10.2% and 6.5%, respectively. Outdoor dogs evidenced adult worm infection rate of 31.2% and microfilaria infection rate of 18.2%. The indoor dogs, however, evidenced adult worm infection rate of 2.8% and microfilaria infection rate of 2.3%. The prevalence in males was more than 2 times that of females. The changing pattern of infection rates by age evidenced a gradual increase, from 2- to 6-year-old dogs, after which, a decrease in infection rates was noted. With regard to chemoprophylaxis, the infection rates of complete and incomplete chemoprophylaxis groups were found to be 2-3 times lower than that of the non-chemoprophylaxis group. The results of the present study indicate that the risk of exposure to D. immitis in pet dogs is quite high, particularly in male outdoor dogs, and chemoprophylactic measures were quite effective.

Efficacy of a single milbemycin oxime administration in combination with praziquantel against experimentally induced heartworm (Dirofilaria immitis) infection in cats

The efficacy of a combination of milbemycin oxime and praziquantel in preventing the establishment of experimentally induced heartworm (Dirofilaria immitis) infection was investigated in a study involving 24 young domestic short-hair cats. The animals were inoculated with 50 infective larvae on day 0. Subsequently they were divided into two groups of 12 animals each. The animals in group 1 were treated once with medicated tablets containing 4 mg milbemycin (minimum dose 2 mg/kg body weight) and 10 mg praziquantel (MILBEMAX) on day 30 after infection. Cats in group 2 received placebo tablets on the same day. On day 183 post-infection a blood sample was taken from each animal before euthanasia and necropsy. The blood samples were tested for the presence of microfilariae and the necropsied animals were examined for the presence of adult worms. Microfilariae were not found in any of the investigated cats. No heartworms were found in the animals in group 1 (treated with medicated tablets). Out of the 12 placebo-treated cats 1 was heartworm-free, whereas all the others were found to be infected with 1-3 adult heartworms.

Immunologic protection against canine heartworm infection

This study was conducted to evaluate protective efficiency of three different protocols for vaccination in canine heartworm infection. To evaluate the three protocols of immunization, dogs were separately immunized with living larvae; 1) immunization with gamma-attenuated infective larvae, 2) with 50 micrograms/kg ivermectin-abbreviation, and 3) with chemical abbreviation plus Freund's complete adjuvant (FCA). Each group was composed of two dogs. All dogs used for this study were subcutaneously challenged with 100 intact third-stage larvae (L3) various days after the last immunization, and the worms in the pulmonary arteries and the right ventricle of the heart were recovered 17 to 25 weeks post-infection. The numbers and the sexes of the worms were determined. A mean of 38 worms was burdened in the group immunized with irradiated L3, 36 worms in the chemically-abbreviated group, but 15.5 worms in the group with chemical abbreviation plus FCA. The percentages of the protection in the former two groups were nearly 50%, but 72.3% in the group with ivermectin plus FCA. The adjuvant enhanced the protective immunity against L3 challenge. Obvious eosinophilia was observed in both immunized and control dogs except for two dogs. There was no correlation between the suppression of eosinophilia and the protective immunity in the present study.