Effect of temperature on the development of the free-living stages of horse cyathostomins

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


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

1966 ◽  
Vol 52 (4) ◽  
pp. 713 ◽  
Author(s):  
Ferron L. Andersen ◽  
Guang-Tsan Wang ◽  
Norman D. Levine

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 483-489 ◽  
Author(s):  
Premvati

Strongyloides papillosus is found to be very common in the Lucknow area where 90% of the sheep are infected. The life-cycle is predominantly indirect, or heterogonic. The development of mature free-living adults takes place between 20° and 37° C., and 34° C. is the optimum temperature. At a temperature of 25° C., the percentage of free-living adults is 60–65 in summer (March to November) and practically 100 in winter (December to February). Immature females can develop at 40° C. in summer, but not in winter, under laboratory conditions.Inhibition experiments in a hot oven incubator with varying percentages of humidity, and in a humidity chamber incubator with constant 100% humidity, maintained at temperatures varying from 40° to 50° C., show that in the humidity chamber incubator mature free-living adults develop at 34° C. after incubation for 12 hr. at 40° C., after 4 hr. at 42° C., after 2 hr. at 45° C. and after 15 min. at 50° C. The hot oven incubator allows mature free-living adults to develop at 34° C. after 8 hr. at 40° C., after 2 hr. at 42° C., after 1 hr. at 45° C. and after 15 min. at 50° C.


Parasitology ◽  
1983 ◽  
Vol 86 (1) ◽  
pp. 105-118 ◽  
Author(s):  
O. Hindsbo

SUMMARYThe development, survival and infectivity of larvae of Nippostrongylus brasiliensis at 10 and 21 °C have been studied. In cultures developed for 1 weekat21 °C but stored at either 10 or 21 °C the mean recovery of larvae in 1·5 h Baermann sediment (46% and 42% of total eggs, respectively) and their infectivity (66% and 70% day 8 p.i. recovery, respectively) at 4 weeks of cultivation were similar. However, at 20 weeks of cultivation only a few larvae survived storage at 21 °C (1·4%) and the survivors showed very low infectivity (4·1%), whereas larvae stored at 10 °C retained most of their survival and infectivity rates (41% and 44%, respectively). In cultures developed and stored at 10 °C a lower mean proportion (17%) of the eggs was recovered as larvae at 4 weeks of cultivation. The mean infectivity rate of these larvae increased from 4 to 12 weeks of cultivation (18 % and 42 %, respectively) but was reduced at 20 weeks of cultivation (27 %). An increased proportion of adult female worms was recovered from rats infected with larvae from cultures showing poor development or survival and the fecundity of the adult females decreased in all groups as the storage time of the cultures was increased. Eggs from low fecundity adult worms showed normal development of larvae. The relation between survival, temperature in the habitat and the geographical distribution of the larvae of N. brasiliensis is discussed.


2021 ◽  
Vol 95 ◽  
Author(s):  
C.L. Achiorno ◽  
G. Minardi ◽  
L. Ferrari

Abstract The different stages of the life cycle of parasites are important components of ecosystems. Changes in environmental conditions may affect free-living stages, host–parasite interactions and ecosystem functioning. The larvae of Chordodes nobilii, which belongs to the parasitic phylum Nematomorpha, are susceptible to extreme temperatures and different pollutants, but the effects of pH and moderate temperature variations have not been evaluated yet. Our objective was to assess the effect of temperature, pH and their interaction on the infectivity of C. nobilii larvae to Aedes aegypti larvae over time. Larvae were treated with factorial combinations of temperature (18, 23 and 28°C), pH (7, 8 and 9) and time periods (24 and 48 h). Results show a highly significant interaction among all variables. The highest infectivity was recorded at 18°C and pH 7 at 24 and 48 h, and the lowest one at 28°C and pH 8 at 24 and 48 h. Infectivity differed significantly among the three temperatures only at pH 8 and 48 h, decreasing with increasing temperature. Our study is the first report of the effect of pH on a Nematomorpha species and suggests that the infectivity of C. nobilii larvae may be affected negatively by an increase in temperature and its interaction with pH and time. Since parasites must be considered for a better understanding of the effects of stressors on freshwater ecosystems, our results may help in the design and analysis of studies of anthropogenic impact.


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