amicarbalide-diisethionate and Disease-Models--Animal

Two in vivo drug resistance assays were developed using gerbils. Cross resistance, involving related babesicides as well as the chemically unrelated antibiotic, oxytetracycline, was demonstrated, but the suggestion that imidocarb may select for pathogenic strains of parasites was not supported. Limited tests of field strains did not detect resistance. It is suggested that an in vitro assay would be more appropriate for surveys through in vivo assays would be essential for confirmatory studies.

Topics: Animals; Antiprotozoal Agents; Babesia; Babesiosis; Carbanilides; Diminazene; Disease Models, Animal; Drug Resistance; Gerbillinae; Imidocarb; Oxytetracycline; Quinolinium Compounds; Reproducibility of Results; Urea

It was found that surprisingly low doses of four babesicides were effective against Babesia divergens in gerbils and it was concluded that this was due to the involvement of host resistance, which may be of a non-specific nature. The efficacy of the drugs relative to each other was the same in gerbils as in cattle and this host-parasite system is evidently more suitable for the screening of babesicides than are other rodent babesia systems. The prophylactic dose of imidocarb dipropionate required to provide a similar degree of protection in gerbils as in cattle was found to be much higher and was very close to toxic levels. Challenge infections resulted in sterile immunity. Acute babesiosis in gerbils could be cured with all four drugs if parasitaemias were below approximately 45 per cent and packed cell volumes above 18 per cent at treatment.

Topics: Animals; Antiprotozoal Agents; Babesiosis; Carbanilides; Diminazene; Disease Models, Animal; Female; Gerbillinae; Imidocarb; Male; Quinolinium Compounds; Urea