The ecology of the free-living stages of Ostertagia ostertagi in a winter rainfall region

1981 ◽  
Vol 32 (2) ◽  
pp. 371 ◽  
Author(s):  
RR Young ◽  
N Anderson
Keyword(s):  
Developmental Stages ◽  
Mortality Rates ◽  
Wide Distribution ◽  
Early Spring ◽  
Initial Population ◽  
Free Living ◽  
Infective Larvae ◽  
Cattle Faeces ◽  
Eggs And Larvae ◽  
Rainfall Region

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.

Populations of free-living stages of Ostertagia ostertagi and O. circumcincta in a winter rainfall region

1983 ◽  
Vol 34 (5) ◽  
pp. 569 ◽  
Author(s):  
RR Young
Keyword(s):  
Population Dynamics ◽  
Survival Rate ◽  
Larval Survival ◽  
Moisture Loss ◽  
Free Living ◽  
Winter Rainfall ◽  
Faecal Pellets ◽  
Infective Larvae ◽  
Cattle Faeces ◽  
Rainfall Region

Pats of cattle faeces containing eggs of the trichostrongylid Osferfagia ostertagi and deposits of sheep faecal pellets containing eggs of O. circumcincta were placed on dry and irrigated pasture plots at four times during the period October 1977 to February 1978. Faecal pellets lost moisture far more rapidly than did dung pats. The rate of moisture loss from both faecal deposits was greater on dry plots than on irrigated plots. Despite large differences between irrigated and dry plots in soil temperature and soil and pasture moisture status, the temperatures recorded in both dung pats and faecal pellets were similar on all plots at each time of deposition. A significantly greater proportion of O . circumcincta eggs was recovered as infective larvae in faeces, on herbage and in soil compared with that of O. osterfagi eggs. Irrigation did not result in either substantially more eggs developing to infective larvae in faeces or higher recoveries of larvae from herbage and soil. No significant differences were detected in temperature or moisture measurements or in parameters of free-living development and larval survival between plots with long or short pasture herbage. There were marked differences between the population dynamics of the infective larvae of Ostertagia spp. and between the numbers of larvae on irrigated and dry plots. On dry plots, O . circumcincta migrated in abundance from faecal deposits after smaller falls of rain than were required for migration of O . ostertagi larvae. Larvae of both species persisted in abundance on the herbage of most dry plots until late spring. On irrigated plots, migration of both species of larvae occurred immediately and was independent of rainfall, but survival rate of larvae was lower than on the corresponding dry plots.

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.

Studies on Ergasilus labracis Krøyer (Cyclopidea: Ergasilidae) parasitic on striped bass, Morone saxatilis, from the lower Chesapeake Bay. I. Distribution, life cycle, and seasonal abundance

1976 ◽  
Vol 54 (4) ◽  
pp. 449-462 ◽  
Author(s):  
I. Paperna ◽  
D. E. Zwerner
Keyword(s):  
Life Cycle ◽  
Chesapeake Bay ◽  
Striped Bass ◽  
Egg Production ◽  
Developmental Stages ◽  
Morone Saxatilis ◽  
Early Spring ◽  
Seasonal Abundance ◽  
Free Living ◽  
Winter Peak

Information on the distribution, life cycle, and seasonal abundance of the copepod Ergasilus labracis Krøyer, parasitic on the gills of lower Chesapeake Bay striped bass, Morone saxatilis (Walbaum), is presented after a 12-month survey. The overall prevalence of E. labracis was 90% in all localities sampled and it was found to be as euryhaline as its host; it has been found in salinities from 0.l‰ to 32.0‰. E. labracis was present and reproductively active throughout the year, suffering only a temporary slowdown in egg production at the beginning of the winter. Peak invasion of striped bass gills by infective larvae occurred during April and May; minor peaks were also recorded during July and October. The free-living stage was estimated to last as long as 6 weeks during early spring. Duration of other developmental stages was also extrapolated. Attempts to rear larvae in the laboratory past the metanauplius stage failed. Larvae could be kept for a maximum of 23 days after hatching if fed nannoplankton and kept at 20 °C in river water of 16–18‰.

scholarly journals Chemical Composition of an Anthelmintic Fraction of Pleurotus eryngii against Eggs and Infective Larvae (L3) of Haemonchus contortus

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Julio Cruz-Arévalo ◽  
José E. Sánchez ◽  
Manases González-Cortázar ◽  
Alejandro Zamilpa ◽  
Rene H. Andrade-Gallegos ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Haemonchus Contortus ◽  
Edible Mushroom ◽  
Mortality Rates ◽  
Normal Phase ◽  
Pleurotus Eryngii ◽  
Gas Chromatography Mass Spectrometry ◽  
Infective Larvae ◽  
Eggs And Larvae

This study was aimed at evaluating the in vitro effect of the edible mushroom (EM) Pleurotus eryngii against the eggs and larvae (L3) of Haemonchus contortus. The evaluation included acetone (AE) and hydroalcoholic (HA) extracts of the following strains: ECS-1138, ECS-1156, ECS-1255, ECS-1258, ECS-1261, ECS-1282, and ECS-1292. The HA extract of the ECS-1255 strain showed the highest effect on mortality rates of L3 (18.83%) at 20 μg/mL. After subjecting this HA extract to a normal phase chromatography column, five fractions were obtained; fraction F5 (100% MeOH) was the most effective against eggs, with hatching inhibition percentages of 88.77 and 91.87% at 20 and 40 mg/mL, respectively. Gas chromatography-mass spectrometry (GC-MS) subjected this fraction to an acetylation reaction to determine the content of the secondary metabolites. The GC-MS analysis showed that the F5 fraction was composed of trehalose CAS: 6138-23-4, polyols (L-iditol CAS: 488-45-9, galactitol CAS: 608-66-2, D-mannitol CAS: 69-65-8, D-glucitol CAS: 50-70-4, and myoinositol CAS: 87-89-8), adipic acid CAS: 124-04-9, stearic acid CAS: 57-11-4, squalene CAS: 111-02-4, and β-sitosterol CAS: 83-46-5.

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.

Observations on the development and survival of the free-living stages of Oesophagostomum dentatum both in their natural environments out-of-doors and under controlled conditions in the laboratory

Parasitology ◽  
1980 ◽  
Vol 81 (3) ◽  
pp. 507-517 ◽  
Author(s):  
J. H. Rose ◽  
A. J. Small
Keyword(s):  
Weather Conditions ◽  
Early Spring ◽  
Climatic Conditions ◽  
Natural Environments ◽  
Free Living ◽  
Infective Larvae ◽  
Oesophagostomum Dentatum ◽  
Wide Range ◽  
Dry Out ◽  
The Relationship

SUMMARYEggs of Oesophagostomum dentatum in faeces deposited on grass plots from May to October developed into infective larvae. Warm wet weather facilitated development but weather conditions which caused the faeces to dry out rapidly resulted in a heavy mortality of eggs and pre-infective larvae. During the winter no development took place and the eggs died. In the early spring and late autumn a few eggs survived and developed into 1st-stage larvae but they died without developing further. In the laboratory no development took place at 4 °C but at temperatures ranging from 10 to 25 °C development into infective larvae was completed, the rate increasing as the temperature rose. Out-of-doors infective larvae survived in faeces and on herbage for 1 year under a wide range of climatic conditions including the exceptionally cold winter of 1978–79. In the laboratory, infective larvae suspended in water survived even longer at temperatures ranging from 4 to 27 °C. They were rapidly killed by continuous freezing and by desiccation when the relative humidity was less than 90%. The relationship between climatic conditions and the development and survival of the free-living stages is discussed.

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.

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.

Prospective enzymes for omega-3 PUFA biosynthesis found in endoparasitic classes within the phylum Platyhelminthes

2020 ◽  
Vol 94 ◽  
Author(s):  
D. Babaran ◽  
M.T. Arts ◽  
R.J. Botelho ◽  
S.A. Locke ◽  
J. Koprivnikar
Keyword(s):  
Parasite Species ◽  
De Novo ◽  
Genomic Data ◽  
Wide Distribution ◽  
Omega 3 ◽  
Free Living ◽  
Chain Pufa ◽  
Pufa Biosynthesis ◽  
Aquatic Food ◽  
Long Chain

Abstract The free-living infectious stages of macroparasites, specifically, the cercariae of trematodes (flatworms), are likely to be significant (albeit underappreciated) vectors of nutritionally important polyunsaturated fatty acids (PUFA) to consumers within aquatic food webs, and other macroparasites could serve similar roles. In the context of de novo omega-3 (n-3) PUFA biosynthesis, it was thought that most animals lack the fatty acid (FA) desaturase enzymes that convert stearic acid (18:0) into ɑ-linolenic acid (ALA; 18:3n-3), the main FA precursor for n-3 long-chain PUFA. Recently, novel sequences of these enzymes were recovered from 80 species from six invertebrate phyla, with experimental confirmation of gene function in five phyla. Given this wide distribution, and the unusual attributes of flatworm genomes, we conducted an additional search for genes for de novo n-3 PUFA in the phylum Platyhelminthes. Searches with experimentally confirmed sequences from Rotifera recovered nine relevant FA desaturase sequences from eight species in four genera in the two exclusively endoparasite classes (Trematoda and Cestoda). These results could indicate adaptations of these particular parasite species, or may reflect the uneven taxonomic coverage of sequence databases. Although additional genomic data and, particularly, experimental study of gene functionality are important future validation steps, our results indicate endoparasitic platyhelminths may have enzymes for de novo n-3 PUFA biosynthesis, thereby contributing to global PUFA production, but also representing a potential target for clinical antihelmintic applications.

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