Effect of Temperature on Development of the Free-Living Stages of Ostertagia ostertagi

1972 ◽  
Vol 58 (6) ◽  
pp. 1037 ◽  
Author(s):  
V. S. Pandey
Parasitology ◽  
1961 ◽  
Vol 51 (3-4) ◽  
pp. 295-307 ◽  
Author(s):  
J. H. Rose

Outdoor observations were made on the rate of development of the free-living stages of O. ostertagi at different times of the year, and on the migratory activities and longevity of the larvae in faeces, on herbage and in soil.The effect of temperature on the rate of development of eggs and larvae in faeces, and the effect of temperature and humidity on the longevity of eggs and larvae when separated from faeces, were studied in the laboratory.The results of these observations are discussed in relation to translation (that is, the process whereby eggs in faeces become infective larvae on herbage available to the grazing animal) and to the transmission of infection in the field.I wish to thank Mr J. F. Michel for providing the infected faeces, and Mr D. A. Griffiths for technical assistance.


1958 ◽  
Vol 36 (4) ◽  
pp. 623-628 ◽  
Author(s):  
Premvati

The optimum temperature for the complete development of the free-living and the infective larvae of Strongyloides fülleborni is 25 °C. Morphological changes are seen at higher or lower temperatures.


2020 ◽  
Vol 12 ◽  
pp. 511-527
Author(s):  
C Lupo ◽  
BL Dutta ◽  
S Petton ◽  
P Ezanno ◽  
D Tourbiez ◽  
...  

Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to 12 mo, depending on the location in which infection was initiated. The effect of temperature was captured by the basic reproduction number (R0), which was >1 at high seawater temperatures, as opposed to values <1 at low temperatures. At the ecosystem scale, simulations showed the existence of long-distance dispersal of free-living bacteria. The western part of the bay could be reached by bacteria originating from the eastern side, though the spread time was greatly increased. Further developments of the model, including the consideration of the anthropogenic movements of oysters and oyster-specific sensitivity factors, would allow the development of accurate maps of epidemiological risks and help define aquaculture zoning.


Author(s):  
A. Merlin ◽  
N. Ravinet ◽  
C. Sévin ◽  
M. Bernez-Romand ◽  
S. Petry ◽  
...  

Parasitology ◽  
1982 ◽  
Vol 85 (1) ◽  
pp. 27-32 ◽  
Author(s):  
M. G. Smeal ◽  
A. D. Donald

SUMMARYPopulations of Ostertagia ostertagi established from fresh larvae and from larvae stored at 4 °C for up to 12 weeks contained about 10% inhibited early 4th-stage larvae. This value rose to 21% after 16 weeks, due to an increase in numbers of inhibited larvae while adult numbers remained unchanged. Storage at 15 °C had no effect. In the case of larvae stored at 4 °C for 8 weeks, increasing the larval dose to 90000 had no significant effect on the proportion of the dose which was inhibited. The response to low temperature storage was much weaker than in previously reported studies on British populations, which accords with our earlier conclusion that low temperature cannot be the effective stimulus for inhibition in Australia.


1984 ◽  
Vol 58 (2) ◽  
pp. 107-112 ◽  
Author(s):  
O.F. Ibarra ◽  
D.C. Jenkings

AbstractThe response of the free-living stages of Nippostrongylus brasiliensis, Nematospiroides dubius, Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia ostertagi to a wide variety of antiparasitic agents in vitro was investigated.All the major broad spectrum veterinary anthelmintics showed good activity against each of these worms with EC30 values varying from about 00002mg/1 for certain benzimidazoles and ivermectin to about 6–5 mg/1 for febantel. Of 22 known narrow spectrum anthelmintics useful only against H. contortus and/or helminths other than trichostrongyles, only 10% showed good activity at concentrations equal to or less than 100mg/1. Further, only one of 15 antiprotozoal agents showed good activity in these tests at the 100mg/1 level.


Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 641-651 ◽  
Author(s):  
J. Barrett

The development of the free-living infective larvae of a homogonic strain Strongyloides ratti is described.The larvae develop only between 15 and 34 °C. Transfer experiments show the temperature block to be in the preparation for the second moult.Within the temperature range 15–34 °C, increasing the temperature speeds up the rate of development of all the larval stages equally, the Q10 for development being 2·5.The maximum percentage development occurs at 20 °C. The percentage development is highest in faeces–peat culture (95% development at 20 °C), whilst the percentage development in charcoal and vermiculite cultures is about the same (75% development at 20 °C.).Larvae grown on charcoal cultures are larger than those grown on vermiculite, which are larger than those grown on peat. No significant difference was found in the length:oesophagus and length:width ratios or in the variability of larvae grown at different temperatures or on different culture media.Different worm densities in the cultures of from 2000 to 10000 larvae per g of culture did not affect either the size of the infective larve or the percentage development.The optimum temperature for survival is 15 °C. Worms grown at 20 °C lived longer than worms grown at any other temperature. There was no evidence of temperature adaptation by the larvae.The infective larvae are positively thermotactic, and show maximum activity at 37 °C.I should like to thank my supervisor, Dr Tate, for his advice and encouragement. The work was carried out during the tenure of a Medical Research Council Scholarship.


2007 ◽  
Vol 102 (2) ◽  
pp. 315-319 ◽  
Author(s):  
Kenji Minato ◽  
Eisaku Kimura ◽  
Yoshimi Shintoku ◽  
Shoji Uga

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