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Biomedical subjects

K S Todd

Publications and source records attributed to K S Todd.

At least 73 records · Page 4Linked to original sources
PubMed1977

Diagnosis of encephalitozoonosis in experimentally infected rabbits by intradermal and immunofluorescence tests.

The indirect immunofluorescence antibody test was performed on serial blood samples from eight young New Zealand White rabbits with experimental encephalitozoonosis. The test showed seroconversion in six of the eight infected rabbits by the 8th day after inoculation and in all rabbits by the 15th day. Antibody titers reached a peak by about the 36th day after inoculation and remained significantly elevated until the termination of the experiment at 84 days after inoculation. None of four sham-inoculated rabbits showed an immunofluorescence response by the 60th day after inoculation. Immunofluorescence and intradermal test responses were compared before infection and at the 60th day after inoculation in a total of 32 experimentally infected rabbits. Both tests were equally effective (100%) in detecting infected animals. Six of eight (first group) and 22 of 24 (second group) experimentally infected rabbits were confirmed histologically to have lesions compatible with encephalitozoonosis. No cross reactions were observed between Encephalitozoon cuniculi and Toxoplasma gondii, Eimeria perforans, or Eimeria stiedai by intradermal test or immunofluorescence test.

Animals↗
PubMed1977

Developmental arrest of Haemonchus contortus larvae in lambs given larval inoculum exposed to different temperatures and storage conditions.

The temperature (15 or 30 C) at which Haemonchus contortus larvae were allowed to develop to the infective (3rd) stage and the temperature at which they were subsequently stored (4, 15, or 30 C) had no effect on the occurrence of developmental arrest (larval impasse) of the larvae in infected lambs. If a large inoculating dose (10,000 larvae) was given to the lambs, a smaller percentage of nematodes was retained (14.2%) then if a small dose (1,000 larvae, 25.8% retention) was given, but the percentage of larvae in developmenttal arrest was greater (7.7% of the retained nematodes vs 0.02%). The temperatures of larval development and storage had no effect on the sex ratio of the adults that developed (46.3% male nematodes).

Animals↗
PubMed1976

Effect of desiccation on the survival of infective Haemonchus contorus larvae under laboratory conditions.

When stored in water at 4 and 20 C, respectively, 42 and 36% of free 3rd-stage, infective larvae of Haemonchus contortus were alive after 256 days. When stored at -95 C, 73% of the free, desiccated larvae died during the 1st half hour and 80% during the 1st half day; thereafter no more died for 255 days, the duration of the experiment. Desiccation protected the larvae against death on storage at temperature below freezing, but it was harmful at temperatures above freezing. H. contortus larvae do not withstand a single episode of desiccation as well as Trichostrongylus colubrformis larvae.

Animals↗
PubMed1976

Effect of temperature on survival of free-living stages of Haemonchus contortus.

One percent or more unembryonated eggs of Haemonchus contortus survived in sheep fecal pellets less than 0.5 hour at -95 C, 2 hours at -28 C, 1 hour at -10 C, 4 days at 4 C, and 1 hour at 45 C. One percent or more embryonated eggs survived 1 hour at -95 and -28C, 12 hours at -10 C, 64 days at 4 C, and 12 hours at 45 C. Over half the unembryonated and embryonated eggs survived only 1 and 4 days, respectively, at 4 C. One percent or more 1st-stage larvae did not survive 0.5 hour at -95 C but did survive 0.5 hour at -28 C, 8 hours at -10 C, 16 days at 4 C, and 1 hour at 45 C. Less than 1% of 2nd-stage larvae survived up to 2 days at -95 C; all were dead by 4 days. Second-stage larvae survived 32 days at -28 C, 8 days at -10 C, 64 days at 4 C, and 2 hours at 45 C. One percent or more 3rd-stage larvae survived 256 days at -95 C, 16 days at -28 C, 32 days at -10 C, more than 256 days at 4 C, 128 days at 20 C, 64 days at 25 and 35 C, and 4 days at 45 C. Thus, the increasing order of survival was unembryonated eggs, 2nd-stage larvae, 1st-stage larvae, embryonated eggs, and 3rd-stage larvae.

Animals↗