PERIODICITY OF DIROFILARIA-IMMITIS MICROFILARIAE IN CANINE AND MURINE HOSTS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 40  (2) , 121-127
Abstract
Microfilariae of D. immitis were recovered from an experimentally infected dog and inoculated i.v. into adult female BALB/c mice. Each mouse received 1 .times. 105 microfilariae. In 1 experiment mice were sublethally irradiated with .gamma. radiation 24 h prior to microfilarial inoculation; microfilariae were counted at 1100 and 2300 h 7, 14, 21, 28, 35 and 42 days after inoculation. A similar experiment was performed in nonirradiated mice to ensure that sublethal irradiation had not caused microfilarial periodicity. In a 3rd experiment microfilaria numbers were determined in sublethally irradiated mice at 4-h intervals for 48 h beginning 14 days after microfilarial inoculation; microfilaria numbers at each bleeding were compared to microfilarial density at the same time in the donor dog. In a 4th experiment 2 groups of mice were irradiated, inoculated and bled as before; 1 group was acclimated to light from 0700 to 1900 h; whereas the other group was acclimated to light from 1900 to 0700 h. The microfilaremia was subperiodic, varying regularly with time in both the dog and mice. Microfilariae in the dog reached maximum numbers during light hours. In each experiment, regardless of actual time, microfilariae in mice reached maximum numbers during dark hours.