Diurnal variation in microfilaremia in a cat experimentally infected with larvae of Dirofilaria immitis.
In five healthy mongrel female cats used, four cats (Cats 1-4) were experimentally inoculated with 100-123 larvae (L(3)) of Dirofilaria immitis. Cat 5 was an uninfected control. Only Cat 1 became microfilaremic on Day 201 after inoculation and the diurnal changes in the microfilaria population were monitored every 2 h for 24 h on Day 237 when a sufficient number of microfilaria were detected in the circulation. The maximum number of microfilaria in the blood (1,350/ml) occurred at 9:00 p.m. and then gradually decreased to the minimum of 300/ml at 7:00 a.m., indicating that the number of microfilaria shows a nocturnal sub-periodic pattern of diurnal rhythm even in peripheral blood of cats as an abnormal host. On postmortem examination, 10 live adult worms (three males and seven females) in Cat 1 and one live adult worm (one male) in Cat 2 were detected.
Hayasaki
M
M
Veterinary Clinical Center, School of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan. hayasaki@agr.yamaguchi-u.ac.jp
Okajima
J
J
Song
K H
KH
Shiramizu
K
K
D000818:Animals; D002371:Cat Diseases / Q000469:parasitology*; D002415:Cats; D002940:Circadian Rhythm; D004183:Dirofilaria immitis / Q000254:growth & development*; D004184:Dirofilariasis / Q000469:parasitology*; D005260:Female; D008297:Male; D008842:Microfilariae / Q000254:growth & development*