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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
06/07/2017 |
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Data da última atualização: |
06/07/2017 |
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Autoria: |
ANDERSEN, F. L.; WANG, G. T.; LEVINE, N. D. |
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Título: |
Effect of temperature on survival of the free-living stages of Trichostrongylus colubriformis. |
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Ano de publicação: |
1966 |
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Fonte/Imprenta: |
The Journal of Parasitology, v. 52, n. 4, p. 713-721, Aug. 1966. |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: The effects of various constant temperatures (between- 95 and 50 C) on unembryonated and embyonated eggs, and on first-, second-, and third-stage larvae of Trichostrongylus colubriformis were studied. The eggs and preinfective larvae were tested in sheep fecal pellets with adequate moisture, while the infective larvae were tested in tap water. The effects on the eggs and preinfective larvae were assessed by the ability of these stages to complete development to infective larvae after storage at various temperatures and times. The effects on the infective larvae were determined by direct observation for motility after storage. The optimum survival temperature for all free-living stages was 4 C. Small numbers of unembryonated eggs survived for 1 day at -95 C, while embryonated eggs, first-, second-, and third-stage larvae survived for 2 days, 4 days, 32 days, and 64 days, respectively, at that temperature. Storage at 50 C was fatal to all stages within 1 day. In general, embryonated eggs were more resistant than unembryonated eggs, and second-stage larvae were more resistant than first-stage larvae at most temperatures and time intervals tested. At the optimum temperature (4 C) embryonated eggs and first- and second-stage larvae survived about the same: 14, 15, and 14%, respectively, of these stages were still alive after 64 days. Infective larvae generally survived better than any of the other free-living stages. After 312 days at 4 C, 95% of them were alive and active; 75% were still alive after 425 days. Alternate freezing and thawing of infective larvae at -28 and -95 C killed practically all larvae after the second freezing, whereas at -10 C repeated freezing had no appreciable effect on the larvae as compared with continuous frozen storage. Infective larvae stored for 308 days at 4 C were still able to infect a worm-free sheep, and larvae which survived freezing at -10, -28, -95, or -195 C exsheathed when tested in vitro. MenosAbstract: The effects of various constant temperatures (between- 95 and 50 C) on unembryonated and embyonated eggs, and on first-, second-, and third-stage larvae of Trichostrongylus colubriformis were studied. The eggs and preinfective larvae were tested in sheep fecal pellets with adequate moisture, while the infective larvae were tested in tap water. The effects on the eggs and preinfective larvae were assessed by the ability of these stages to complete development to infective larvae after storage at various temperatures and times. The effects on the infective larvae were determined by direct observation for motility after storage. The optimum survival temperature for all free-living stages was 4 C. Small numbers of unembryonated eggs survived for 1 day at -95 C, while embryonated eggs, first-, second-, and third-stage larvae survived for 2 days, 4 days, 32 days, and 64 days, respectively, at that temperature. Storage at 50 C was fatal to all stages within 1 day. In general, embryonated eggs were more resistant than unembryonated eggs, and second-stage larvae were more resistant than first-stage larvae at most temperatures and time intervals tested. At the optimum temperature (4 C) embryonated eggs and first- and second-stage larvae survived about the same: 14, 15, and 14%, respectively, of these stages were still alive after 64 days. Infective larvae generally survived better than any of the other free-living stages. After 312 days at 4 C, 95% of them were alive and act... Mostrar Tudo |
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Palavras-Chave: |
Faeces; Larval stage; Trichostrongyloidea. |
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Thesaurus Nal: |
Eggs; Freezing; Nematoda; Parasitology; Sheep; Trichostrongylus colubriformis. |
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Categoria do assunto: |
H Saúde e Patologia |
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Marc: |
LEADER 02653nam a2200241 a 4500
001 2072122
005 2017-07-06
008 1966 bl uuuu u0uu1 u #d
100 1 $aANDERSEN, F. L.
245 $aEffect of temperature on survival of the free-living stages of Trichostrongylus colubriformis.
260 $aThe Journal of Parasitology, v. 52, n. 4, p. 713-721, Aug. 1966.$c1966
520 $aAbstract: The effects of various constant temperatures (between- 95 and 50 C) on unembryonated and embyonated eggs, and on first-, second-, and third-stage larvae of Trichostrongylus colubriformis were studied. The eggs and preinfective larvae were tested in sheep fecal pellets with adequate moisture, while the infective larvae were tested in tap water. The effects on the eggs and preinfective larvae were assessed by the ability of these stages to complete development to infective larvae after storage at various temperatures and times. The effects on the infective larvae were determined by direct observation for motility after storage. The optimum survival temperature for all free-living stages was 4 C. Small numbers of unembryonated eggs survived for 1 day at -95 C, while embryonated eggs, first-, second-, and third-stage larvae survived for 2 days, 4 days, 32 days, and 64 days, respectively, at that temperature. Storage at 50 C was fatal to all stages within 1 day. In general, embryonated eggs were more resistant than unembryonated eggs, and second-stage larvae were more resistant than first-stage larvae at most temperatures and time intervals tested. At the optimum temperature (4 C) embryonated eggs and first- and second-stage larvae survived about the same: 14, 15, and 14%, respectively, of these stages were still alive after 64 days. Infective larvae generally survived better than any of the other free-living stages. After 312 days at 4 C, 95% of them were alive and active; 75% were still alive after 425 days. Alternate freezing and thawing of infective larvae at -28 and -95 C killed practically all larvae after the second freezing, whereas at -10 C repeated freezing had no appreciable effect on the larvae as compared with continuous frozen storage. Infective larvae stored for 308 days at 4 C were still able to infect a worm-free sheep, and larvae which survived freezing at -10, -28, -95, or -195 C exsheathed when tested in vitro.
650 $aEggs
650 $aFreezing
650 $aNematoda
650 $aParasitology
650 $aSheep
650 $aTrichostrongylus colubriformis
653 $aFaeces
653 $aLarval stage
653 $aTrichostrongyloidea
700 1 $aWANG, G. T.
700 1 $aLEVINE, N. D.
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Embrapa Caprinos e Ovinos (CNPC) |
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