Some observations on the free-living stages of Ostertagia ostertagi, a stomach worm of cattle

Parasitology ◽  
1961 ◽  
Vol 51 (3-4) ◽  
pp. 295-307 ◽  
Author(s):  
J. H. Rose
Keyword(s):  
Technical Assistance ◽  
Effect Of Temperature ◽  
Free Living ◽  
Ostertagia Ostertagi ◽  
Rate Of Development ◽  
Infective Larvae ◽  
Grazing Animal ◽  
Temperature And Humidity ◽  
Eggs And Larvae

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.

Observations on the free-living stages of the stomach worm Haemonchus contortus

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 469-481 ◽  
Author(s):  
J. H. Rose
Keyword(s):  
Haemonchus Contortus ◽  
Free Living ◽  
Rate Of Development ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Eggs And Larvae ◽  
Heavy Mortality

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.

Observations on the free-living stages of strongylid nematodes of the horse

Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 461-477 ◽  
Author(s):  
C. P. Ogbourne
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Infective Stage ◽  
Free Living ◽  
Rate Of Development ◽  
Infective Larvae ◽  
Strongylus Vulgaris ◽  
Different Temperatures ◽  
Eggs And Larvae

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.

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
Keyword(s):  
Infective Stage ◽  
Optimum Temperature ◽  
Free Living ◽  
Infective Larvae ◽  
Faecal Culture ◽  
Temperature And Humidity ◽  
Effects Of Temperature ◽  
Eggs And Larvae

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.

The ecology of the free-living stages of Trichostrongylus colubriformis

Parasitology ◽  
1967 ◽  
Vol 57 (3) ◽  
pp. 533-547 ◽  
Author(s):  
T. E. Gibson ◽  
G. Everett
Keyword(s):  
Technical Assistance ◽  
Infected Sheep ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Faecal Output ◽  
Infective Larvae ◽  
June July ◽  
Eggs And Larvae ◽  
Do So ◽  
Favourable Development

The development and survival of the eggs and larvae of T. colubriformis was studied by spreading the daily faecal output of an infected sheep for 1 or 2 weeks on grass plots 6 ft square. The observations were carried out for 3 years and broadly similar results were obtained in each year. Eggs placed on the ground from November to February failed to develop. A large proportion of the eggs placed on the ground in March disintegrate but those which develop do so slowly. Infective larvae are not produced for 8–12 weeks and they are relatively short lived. As conditions become more favourable development becomes more rapid, taking 8 weeks in April 6 weeks in May and only 1 week in June, July and August. A larger proportion of the eggs develop into infective larvae and their time of survival increases. On most plots larvae did not die out until the following April. The prolonged period of snow during the winter of 1962–63 tended to preserve larvae rather than kill them. The relevance of these results to the control of trichostrongylosis is discussed and it is concluded that it would be impossible under British conditions to devise a system of rotational grazing which would satisfactorily control trichostrongylosis and at the same time ensure economic utilization of the herbage.We are grateful to Mr C. R. Phillips and Mr T. Doy for technical assistance during the course of this investigation.

STUDIES ON STRONGYLOIDES OF PRIMATES: IV. EFFECT OF TEMPERATURE ON THE MORPHOLOGY OF THE FREE-LIVING STAGES OF STRONGYLOIDES FULLEBORNI

1958 ◽  
Vol 36 (4) ◽  
pp. 623-628 ◽  
Author(s):  
Premvati
Keyword(s):  
Morphological Changes ◽  
Effect Of Temperature ◽  
Optimum Temperature ◽  
Free Living ◽  
Infective Larvae ◽  
Complete Development

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.

Investigations into the free-living phase of the life-cycle of Nematodirus helvetianus

Parasitology ◽  
1966 ◽  
Vol 56 (4) ◽  
pp. 679-691 ◽  
Author(s):  
J. H. Rose
Keyword(s):  
Life Cycle ◽  
Technical Assistance ◽  
Free Living ◽  
Temperature And Humidity ◽  
Effects Of Temperature

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.

The effect of temperature on the development and survival of the infective larvae of Strongyloides ratti Sandground, 1925

Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 641-651 ◽  
Author(s):  
J. Barrett
Keyword(s):  
Culture Media ◽  
Maximum Activity ◽  
Temperature Adaptation ◽  
Effect Of Temperature ◽  
Free Living ◽  
Larval Stages ◽  
Infective Larvae ◽  
Significant Difference ◽  
Show Maximum Activity ◽  
Different Temperatures

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.

The effect of temperature and humidity on development and longevity of Amblyomma triguttatum triguttatum (Acarina: Ixodidae)

1992 ◽  
Vol 82 (2) ◽  
pp. 203-208 ◽  
Author(s):  
A.A. Guglielmone
Keyword(s):  
Harsh Environments ◽  
Oviposition Period ◽  
Effect Of Temperature ◽  
Rate Of Development ◽  
Saturation Deficit ◽  
High Saturation ◽  
Temperature And Humidity ◽  
Low Humidity ◽  
Desert Habitat ◽  
C 50

AbstractThe development and longevity of Amblyomma triguttatum triguttatum Koch were studied at temperatures of 15, 20, 25, 30, 35 and 40°C, and humidities with water staturation deficits of 2–3, 8–9 and 16–17 mm Hg. No stage developed at 40°C and the engorged larva was the only stage able to develop at 15°C. The rate of development was inversely related to temperature, with the exception of the pre-oviposition period of the engorged female which was longer at 35°C than at 30°C. The egg was the most vulnerable stage to high saturation deficit (low humidity) but some did survive in constant conditions of 16–17 mm Hg, showing an adaptation to harsh environments; A. t. triguttatum survives in a semi-desert habitat. The longevity of the unfed stages increased from the larvae, nymphs to adults. The longevity decreased with increase of temperature and decrease of humidity with the exception of adults maintained at 30°C and 16–17 mm Hg, which had a longer viability to the same saturation deficit at 20°C (50% mortality) and 25°C (50% and 100% mortality).

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