VETERINARY ARTICLES & FINDINGS

BY STEVEN METCALFE
BSc BVMS (Hons) MSc MACVSc

 

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Investigations into the efficacy of doramectin on reactivated somatic larvae of Ancylostoma caninum Ercolani 1859 (Ancylostomatidae) in pregnant bitches.

Schneider T, Heidemann R, Epe C, Stoye M
Institute of Parasitology, School of Veterinary Medicine, Hannover, Germany.


The aim of this investigation was to examine whether reactivated somatic Ancylostoma caninum larvae can be eliminated by the administration of doramectin to pregnant bitches. Four pregnant bitches experimentally infected with 20,000 third-stage larvae of A. caninum were treated subcutaneously with 1 mg doramectin per kg body weight on day 55 of the pregnancy (5-8 days before parturition). Another four experimentally infected pregnant bitches served as controls. The single doramectin treatment completely prevented galactogenic infections in the puppies. Neither intestinal stages nor somatic larvae could be found. The administration of doramectin caused no local or generalized side-effects in the bitches. All 16 puppies of the treated bitches were born healthy and remained so during the whole trial period. Beginning during the third week after birth, all 20 puppies of the untreated bitches developed a severe microcytic, hypochromic anaemia. They had to be killed between 17 and 35 days after birth. Post mortem, they revealed a total of 8649 intestinal stages of A. caninum.

A study on the prevention of prenatal and galactogenic Toxocara canis infections in pups by treatment of infected bitches with ivermectin or doramectin

Epe C, Pankow WR, Hackbarth H, Schnieder T, Stoye M
Institute of Parasitology, School of Veterinary Medicine, Hannover, Germany.


Investigations were carried out to test the efficacy of a two dose treatment with ivermectin or doramectin on reactivated larvae of Toxocara canis in bitches to prevent prenatal and galactogenic infections of their pups. Thirty pregnant bitches were treated by subcutaneous injection of ivermectin or doramectin on day 40 and 50 post conception (p.c.) each with a dose of 1 mg/kg body weight. The efficacy of the treatments was determined by faecal examinations and by comparing the number of infected pups and the onset of patency in each group of pups. 1. Patient infections with T. canis were seen in pups from untreated bitches from day 21 after birth and all pups were coproscopically positive one week later. To prevent severe clinical symptoms all pups in this group were treated with anthelmintics on day 42 after birth. 2. Pups from ivermectin treated bitches occasionally exhibited patent infections from day 28 after birth onwards; pups from doramectin group exhibited infections from day 56 after birth. The number of patently infected pups in both groups increased till 70 days after birth, probably because of postnatal infections. 3. 28 days after parturition, T. canis infections became patent in all untreated bitches. Single bitches in the ivermectin and doramectin groups developed patent infections after day 49 after parturition. All coproscopically positive bitches had patently infected pups in their litters. 4. The contamination of the environment with eggs of T. canis was calculated from the results of the faecal examinations. (ABSTRACT TRUNCATED AT 250 WORDS)

Investigations into the prevention of neonatal Toxocara canis infections in puppies by application of doramectin to the bitch.

Schnieder T, Kordes S, Epe C, Kuschfeldt S, Stoye M
Institute of Parasitology, School of Veterinary Medicine, Hannover, Germany.


The aim of this investigation was to examine whether the treatment of bitches with doramectin is able to prevent pre-natal and galactogenic infections with Toxocara canis in their pups. Five experimentally infected beagle bitches were treated subcutaneously with 1 mg doramectin per kg body weight on each of days 40 and 55 of their pregnancy. Another infected bitch served as an untreated control. The efficacy of the medication was examined by counting the intestinal stages and somatic larvae in bitches and pups. The treatment did not completely prevent perinatal infections with T. canis. Intestinal stages and/or somatic larvae occurred in 16 of 20 pups. Seven pups developed patent infections. Compared to the control pups, the average worm burden (intestinal stages) of pups from treated bitches was less than 1%. No impairment of condition or physical development was noticed in the pups during the investigations. From the second week of life, the pups of the non-medicated bitch showed signs of a severe toxocarosis. No side effects were seen in the bitches after treatment with doramectin.

The efficacy of doramectin on arrested larvae of Ancylostoma caninum in early pregnancy of bitches.

Schnieder T, Lechler M, Epe C, Kuschfeldt S, Stoye M
Institute of Parasitology, School of Veterinary Medicine, Hannover, Germany.


The efficacy of doramectin treatment on arrested A. caninum larvae during early pregnancy of bitches was examined. Four bitches were percutaneously infected with 20,000 third-stage larvae of A. caninum on the day of conception and treated subcutaneously with 1 mg doramectin per kg body weight on day 30 of pregnancy. Four infected untreated pregnant bitches served as controls. A single application of dormectin substantially reduced the number of somatic larvae in bitches and the number of intestinal stages in bitches and puppies. However, it did not completely prevent lactogenic transmission of A. caninum larvae because five out of 23 puppies from three litters of the treated bitches harboured adult worms in their intestines, two of them shed eggs with the faeces. Although clinical disease did not occur in puppies from treated bitches the efficacy of the treatment was not satisfactory from an epidemiological point of view. Despite the treatment puppies with patent infections contaminated their environment with high numbers of eggs thus producing an intolerable infection risk for dogs and humans. No fetotoxic side-effects of the early treatment with doramectin were seen.


 

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Steven S.  Metcalfe BSc BVMS (Hons) MSc MACVSc
Applecross Veterinary Surgery
9 Sleet Road, Applecross,
Western Australia
PHONE: (08) 93647666
Email: ssmetcalfe@bigpond.co

 

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