THE EFFECTS OF TEMPERATURE AND HUMIDITY ON THE FREE-LIVING STAGES OF TRICHOSTRONGYLUS RETORTAEFORMIS

1959 ◽  
Vol 37 (3) ◽  
pp. 305-316 ◽  
Author(s):  
Devandra Prasad

The optimum temperature for development of Trichostrongylus retortaeformis is about 25 °C in a wet faecal culture, when the infective stage is reached in from 3 to 5 days, but at 3 to 5 °C a few larvae can develop in 8 to 10 weeks, and infective larvae can survive for 13 weeks. Both eggs and larvae can survive desiccation for considerable periods.

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 469-481 ◽  
Author(s):  
J. H. Rose

Outdoor observations were made on the rate of development of the free-living stages of H. contortus at different times of the year, and on the migratory activities and longevity of the larvae in faeces, on herbage and in soil.The effects of temperature and humidity on the survival and development of eggs and larvae, both in faeces and when separated from the faeces, were studied in the laboratory.The results of these observations are discussed in relation to the heavy mortality of the free-living stages of H. contortus and to the transmission of infection in the field.


Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 461-477 ◽  
Author(s):  
C. P. Ogbourne

Observations have been made on the development and survival of the free-living stages in faeces deposited out of doors at different times of year, and on the migration of infective larvae to the surrounding herbage. Laboratory experiments were performed to assist in the interpretation of the field observations. Studies were made on the rate of development to the infective stage in faeces kept at different temperatures. The rates at which eggs and larvae of Strongylus vulgaris, S edentatus, S. equinus and Trichonema nassatum developed on faecal-agar cultures at different temperatures were compared. Studies were also made on the effect of desiccation of faeces on the development and survival of the free-living stages. The results of these observations are discussed in relation to the development of herbage infestations on British pastures.


1961 ◽  
Vol 39 (1) ◽  
pp. 47-53 ◽  
Author(s):  
S. P. Gupta

The effects of temperature on the survival and development of the free-living stages of Trichostrongylus retortaeformis have been studied using agar cultures inoculated with pure cultures of Escherichia coli. The ova hatched and infective larvae developed at temperatures ranging from 5 °C to 30 °C, but 35 °C was lethal in 24 hours. The time of development of the larvae to the infective stage was inversely proportional to the ambient temperature between the limits of 10 °C and 30 °C. The longevity in water of third-stage larvae previously cultured at 20 °C, 25 °C, and 30 °C was studied at temperatures ranging from 5 °C to 40 °C.


1959 ◽  
Vol 37 (3) ◽  
pp. 247-257 ◽  
Author(s):  
H. C. Gibbs ◽  
K. E. Gibbs

The effects of temperature on the development of the free-living stages of Dochmoides stenocephala (Railliet, 1884) have been studied using agar cultures. Development was obtained at as low a temperature as 7.5 °C. The optimum temperature for the free-living stages was considered to be 20 °C. The time of development of the larvae to the infective stage was inversely proportional to the ambient temperature between the limits of 7.5 °C and 27 °C.


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.


1947 ◽  
Vol 24 (1-2) ◽  
pp. 79-94
Author(s):  
L. E. S. EASTHAM ◽  
F. SEGROVE

1. The effects of temperature and humidity on the duration of each instar of the life cycle of Calandra granaria Linn. have been examined. The insects were reared at temperatures ranging from 15 to 30° C. and at atmospheric humidities ranging from 40 to 80% R.H. 2. A method is described for assessing the effect of temperature as an independent factor. 3. The temperatures employed fall within the ‘vital zone’. Extrapolation indicates the threshold temperature to be approximately 11° C. for the egg and larval instars though somewhat lower for the pupa. 30° C. is below the optimum temperature. 4. The durations of the egg and pupal stages are not affected by atmospheric humidity. 5. The duration of all larval instars is affected by moisture. It is suggested that this is largely due to atmospheric humidity and that food water is of little significance. 6. Shortage of moisture acts as an obstacle to development. Evidence is presented which indicates that drier atmospheres tend to desiccate the insect and that desiccation is responsible for retarded growth and development. 7. Since much earlier work on temperature and moisture has been done on fasting insects and, therefore, on insects deficient in one of the most important environmental factors, we suggest that our results, incomplete as they are, indicate the need for new approaches to be made. More complete data on feeding insects under controlled conditions of food, temperature and moisture are required, from which can be drawn up more complete balance sheets of development involving measurements of food utilization and respiratory rates.


Parasitology ◽  
1966 ◽  
Vol 56 (4) ◽  
pp. 679-691 ◽  
Author(s):  
J. H. Rose

The free-living phase of the life-cycle of Nematodirus helvetianus was studied out of doors on grass plots and the effects of temperature and humidity on the free-living stages were studied in the laboratory. The results of these observations are discussed in relation to the bionomics of N. battus and N. filicollis, and tentative deductions made regarding the epidemiology of N. helvetianus infection.I wish to thank Mr J. Bailey for technical assistance.


2008 ◽  
Vol 45 (1) ◽  
pp. 32-40 ◽  
Author(s):  
I. Langrová ◽  
I. Jankovská ◽  
J. Vadlejch ◽  
M. Libra ◽  
A. Lytvynets ◽  
...  

AbstractThe present work describing both laboratory and field experiments was performed to assess the effects of desiccation and UV radiation on the development and survival of free-living stages of equine cyathostomins.Cyathostomin larvae in horse faeces did not develop to the infective stage when faecal humidity levels dropped below 23 %, nonetheless solitary preinfective larvae were still recovered after 151 days (humidity 19.5 %). The development to infective stage after remoistening occurred for the last time after 54 days following desiccation.Preinfective stages are susceptible to the effects of the direct desiccation stage. The preinfective larvae were rapidly killed within one minute, the cyathostomin eggs within 5 hours. The numerous normal mobile infective larvae were encountered after 35 days of the desiccated period. The preinfective stage of cyathostomins also showed very little tolerance to direct sun radiation: most eggs were killed by the exposure within 3 hours and the preinfective larvae within 1 hour. The survival of infective larvae was, on the other hand, unaffected by sun radiation after 7 days (P < 0.05). However, desiccated infective larvae were then found to be susceptible to UV radiation, resulting in total mortalities after 5 days.


1981 ◽  
Vol 32 (2) ◽  
pp. 371 ◽  
Author(s):  
RR Young ◽  
N Anderson

On a series of pasture plots, 500 g pats of cattle faeces containing eggs of the trichostrongylid Ostevtagia ostertagi were deposited at intervals of about 6 weeks from June 1976 to June 1977. The development and survival of eggs and larvae in dung pats and the survival of larvae on surrounding herbage and soil were measured and expressed as a percentage of the initial population of eggs. During summer months comparisons were made between the pats on irrigated and those on non-irrigated plots. Minimum temperatures within dung pats were always greater than those required for development, and infective larvae were recovered from all plots. The onset of development was delayed from 3 to 12 days in summer and from 34 to 68 days in winter, which led to a wide distribution of developmental stages. Rates of development were closely related to the temperatures in soil and dung pats, and mortality rates of pre-infective stages increased very rapidly with increasing temperatures and decreasing moisture levels. Infective larvae were present in abundance on herbage and in soil between 6 and 10 weeks after deposition, provided that the moisture content of these was high. Mortality of these larvae was low during winter and early spring but increased rapidly in mid- to late spring, irrespective of the time of deposition of dung pats. Mortality rates of infective larvae in dung pats deposited in either spring or summer were low and a large proportion of these larvae were capable of moving into herbage and soil after autumn rains. Irrigation during summer did not provide ideal conditions for the development of infective larvae from eggs, but hastened larval migration from dung pats.


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