Efficacy and safety of subcutaneous methadone hydrochloride in four-toed hedgehogs (Atelerix albiventris)

OBJECTIVE

To evaluate the efficacy and safety of SC methadone in four-toed hedgehogs.

ANIMALS

9 to 12 healthy adult four-toed hedgehogs (7 to 9 males and 3 females).

METHODS

Hedgehogs underwent 3 randomized, blinded, placebo-controlled, complete crossover studies. Hind limb withdrawal latencies in response to an acute thermal noxious stimulus were measured to evaluate the antinociceptive efficacy of methadone. Single doses of SC methadone were evaluated at 0.5 and 1 mg/kg for dose-dependent effects. Additionally, methadone (1.5 mg/kg) was administered at different concentrations to assess the effect of injection volume on antinociceptive efficacy. Finally, the safety of multiple doses of methadone (1.5 mg/kg, SC, q 2 h, for 3 doses) was also evaluated. In addition to monitoring behavior during latency measurements, animals were assessed for overt sedation. Food intake, body weight, and running wheel activity were assessed daily for 6 days following methadone administration to evaluate for adverse effects.

RESULTS

Methadone at 1 and 1.5 mg/kg provided antinociception lasting < 2 hours, and injection volume had no significant effect on efficacy. Methadone at 0.5 mg/kg did not induce antinociception. Methadone produced transient abnormal behaviors in all hedgehogs, with more animals affected at the 1.5-mg/kg dose. Behaviors included periods of standing motionless, vocalization, chewing motions, and paw raising. Single- or multiple-dose administration of methadone had no significant effect on total food intake, body weight, or running wheel activity.

CLINICAL RELEVANCE

The results of this study provide additional information on providing analgesia to hedgehogs. Subcutaneous methadone (1 to 1.5 mg/kg) can be used for short-term antinociception in hedgehogs.

Combined morphology and DNA-barcoding to identify Plagiorhynchus cylindraceus cystacanths in Atelerix algirus

The acanthocephalan parasite Plagiorhynchus cylindraceus has a global distribution and utilizes isopods and birds as intermediate and definitive hosts, respectively. Occasionally, mammals of various orders can act as paratenic hosts. In hedgehogs, severe cases have been reported in juvenile specimens due to secondary infections, as a consequence of complete penetrations of the intestinal wall by cystacanths. In a 66-month study period, we found seven larvae of this parasite encysted in both, the peritoneal cavity and intestine of the Algerian hedgehog, Atelerix algirus in Majorca. Morphology alone was insufficient to identify the species, due to the lack of previous reports and taxonomy-informative characters. In the present report, we combined the use of morphology and the DNA-barcoding approach to confirm to identify cystacanths as P. cylindraceus. This is the first report of this parasite in this hedgehog species. The epidemiological implications will be discussed, including the risk of zoonosis and the importance of using modern approaches to identify immature acanthocephalan larvae in wildlife hosts.