THE EFFECTS OF TEMPERATURE ON THE SURVIVAL AND DEVELOPMENT OF THE FREE-LIVING STAGES OF TRICHOSTRONGYLUS RETORTAEFORMIS ZEDER (NEMATODA)

1961 ◽  
Vol 39 (1) ◽  
pp. 47-53 ◽  
Author(s):  
S. P. Gupta
Keyword(s):  
Escherichia Coli ◽  
Ambient Temperature ◽  
Infective Stage ◽  
Free Living ◽  
Infective Larvae ◽  
Third Stage ◽  
Survival And Development ◽  
Pure Cultures ◽  
Effects Of Temperature

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.

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 EFFECTS OF TEMPERATURE ON THE DEVELOPMENT OF THE FREE-LIVING STAGES OF DOCHMOIDES STENOCEPHALA (RAILLIET, 1884) (ANCYLOSTOMIDAE: NEMATODA)

1959 ◽  
Vol 37 (3) ◽  
pp. 247-257 ◽  
Author(s):  
H. C. Gibbs ◽  
K. E. Gibbs
Keyword(s):  
Ambient Temperature ◽  
Infective Stage ◽  
Optimum Temperature ◽  
Free Living ◽  
Effects Of Temperature

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.

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.

scholarly journals Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes

2020 ◽  
Vol 117 (30) ◽  
pp. 17913-17923 ◽  
Author(s):  
Spencer S. Gang ◽  
Michelle L. Castelletto ◽  
Emily Yang ◽  
Felicitas Ruiz ◽  
Taylor M. Brown ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Strongyloides Stercoralis ◽  
Sensory Cues ◽  
Ancylostoma Ceylanicum ◽  
Free Living ◽  
Infective Larvae ◽  
Host Seeking ◽  
Third Stage ◽  
Olfactory Preferences ◽  
Insight Into

Approximately 800 million people worldwide are infected with one or more species of skin-penetrating nematodes. These parasites persist in the environment as developmentally arrested third-stage infective larvae (iL3s) that navigate toward host-emitted cues, contact host skin, and penetrate the skin. iL3s then reinitiate development inside the host in response to sensory cues, a process called activation. Here, we investigate how chemosensation drives host seeking and activation in skin-penetrating nematodes. We show that the olfactory preferences of iL3s are categorically different from those of free-living adults, which may restrict host seeking to iL3s. The human-parasitic threadwormStrongyloides stercoralisand hookwormAncylostoma ceylanicumhave highly dissimilar olfactory preferences, suggesting that these two species may use distinct strategies to target humans. CRISPR/Cas9-mediated mutagenesis of theS. stercoralis tax-4gene abolishes iL3 attraction to a host-emitted odorant and prevents activation. Our results suggest an important role for chemosensation in iL3 host seeking and infectivity and provide insight into the molecular mechanisms that underlie these processes.

Migration, growth, and morphogenesis of Dracunculus insignis (Nematoda: Dracunculoidea)

1975 ◽  
Vol 53 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Vincent Frederick Joseph Crichton ◽  
Mary Beverley-Burton
Keyword(s):  
Quantitative Data ◽  
Subcutaneous Tissue ◽  
Abdominal Cavity ◽  
Final Host ◽  
Prepatent Period ◽  
Infective Stage ◽  
Infective Larvae ◽  
Third Stage ◽  
Migratory Route

Larvae of Dracunculus insignis developed to the infective stage in experimentally infected Cyclops vernalis and C. bicuspidatus thomasi kept at 24 C. The first molt occurred at 8–9 days and the second at 13–16 days. Second- and third-stage larvae are briefly described. Infective larvae were administered to raccoon (Procyon lotor) and mink (Mustela vison) and necropsies were performed at predetermined intervals for the determination of the migratory route. In raccoon, third-stage larvae were recovered from the gut wall and mesentery of the abdominal cavity on the 1st day. Larvae were found in the intercostal muscles by the 5th day and in the subcutaneous tissue of the thorax and abdomen by the 7th day. Development to fourth stage was complete by the 19th day. Sexual differences were apparent by the 34th day and worms were present in subcutaneous tissue of the thorax, abdomen, and inguinal region. Male worms were mature at 60 days and females at 65–70 days. Larvigerous females were found in the extremities as early as 120 days post infection. The prepatent period was 354 (309–410) days. Similar results were obtained from mink. Quantitative data on the distribution of worms in various locations within the final host at different times after infection are included.

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.

Effects of temperature acclimation on infection of Echinocephalus sinensis (Nematoda: Gnathostomatidae) from oysters to kittens

1977 ◽  
Vol 55 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
Ronald C. Ko
Keyword(s):  
Ambient Temperature ◽  
Crassostrea Gigas ◽  
Temperature Acclimation ◽  
Boiling Water ◽  
Third Stage ◽  
Effects Of Temperature ◽  
The Tropics

About 700 oysters (Crassostrea gigas) were acclimated in the laboratory to 33, 28, 20–24, 15, and 5 °C. Third-stage larvae of Echinocephalus sinensis Ko, 1975 recovered from the tissues of these molluscs were fed to 31 kittens which were examined 18 h postinfection. The number of successful infections produced and the number of worms located in tissues of kittens were found to be directly related to the ambient temperature of the molluscan host. Substantial infections were obtained only with worms from 33 and 28 °C. Worms could be effectively killed if the infected oysters were deep fried with batter for 7 s or dipped in boiling water for 30 s. The possibility of finding other nematodes of poikilotherms similar to E. sinensis in the tropics is briefly discussed.

scholarly journals The influence of desiccation and UV radiation on the development and survival of free-living stages of cyathostomins under field and laboratory conditions

2008 ◽  
Vol 45 (1) ◽  
pp. 32-40 ◽  
Author(s):  
I. Langrová ◽  
I. Jankovská ◽  
J. Vadlejch ◽  
M. Libra ◽  
A. Lytvynets ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Field Experiments ◽  
The Other ◽  
Infective Stage ◽  
Free Living ◽  
Infective Larvae ◽  
Laboratory Conditions ◽  
Other Hand ◽  
Field And Laboratory Conditions

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.

Dung-derived biological agents associated with reduced numbers of infective larvae of equine strongyles in faecal cultures

1998 ◽  
Vol 72 (1) ◽  
pp. 21-26 ◽  
Author(s):  
J. Bird ◽  
M. Larsen ◽  
P. Nansen ◽  
H.O. Kraglund ◽  
J. Grønvold ◽  
...  
Keyword(s):  
Adult Female ◽  
Soil Organisms ◽  
Climate Chamber ◽  
Free Living ◽  
Treatment Groups ◽  
Infective Larvae ◽  
Baermann Technique ◽  
High Inoculum ◽  
Third Stage ◽  
The Two Cultures

AbstractTwo sets of dung-derived organisms from soil routinely fertilized with manure (MA) and soil chemically fertilized (CH) were cultured separately in the laboratory. Baermannized organisms from these cultures were added to 20 g of faeces from strongyle-infected horses to form three treatment groups: (i) no soil organisms; (ii) low inoculum of soil organisms containing all organisms present in a suspension of approximately 100 adult female free-living nematodes; and (iii) high inoculum containing those soil organisms present with approximately 1000 adult female free-living nematodes. Three studies were conducted using MA cultures and faeces containing 50 strongyle epg, CH cultures and faeces containing 1500 strongyle epg, and a mixture of soil organisms from the two cultures (MC) and faeces containing 600 strongyle epg. Within each study, five control cultures and 15 each of low and high inoculum cultures were prepared and incubated at 24°C and 95% humidity in a climate chamber for 15 days. Parasitic and free-living nematodes were then recovered by the Baermann technique and counted. The numbers of third stage larvae were significantly lower in the high inoculum group compared to controls. The percent reductions in the number of third stage larvae for the low and high inoculum groups were 63.6% and 90.9%, 85.1% and 97.1%, 84.5% and 98.4% for MA, CH, and MC studies, respectively, indicating that mortality increased with the number of soil organisms added to cultures. Examination of the source cultures detected the presence of two species of nematophagous fungi and three genera of free-living nematodes reported to be predacious.

The control of trichostrongyle larvae (Nematoda) by fumigation in relation to their bionomics

Parasitology ◽  
1965 ◽  
Vol 55 (1) ◽  
pp. 29-44 ◽  
Author(s):  
R. F. Sturrock
Keyword(s):  
Laboratory Experiments ◽  
Imperial College ◽  
The Other ◽  
Lateral Movement ◽  
Field Station ◽  
Infective Larvae ◽  
Third Stage ◽  
Pure Cultures ◽  
Average Activity ◽  
Rate Of Movement

Laboratory experiments indicated that third-stage larvae of T. axei and T colubriformis were able to penetrate soil to a depth of 12 in. or more, although most larvae remained in the upper 2 in. No geotaxis was observed.Heavy downflows of water caused severe mortalities but did not affect the rate of movement of surviving larvae through the soil. Very limited random lateral movement occurred in turf, being more pronounced in the presence of faeces. Prolonged desiccation was extremely lethal to infective larvae. The activity of larvae was directly and linearly proportional to normal temperatures. The average activity of groups of larvae declined with time.The author wishes to acknowledge the assistance and facilities provided by Professor B. G. Peters and the other members of staff of Imperial College Field Station, and to thank Dr C. W. R. Spedding for helpful criticism and supplying culture lambs; and Dr T. E. Gibson and Dr P. Silverman for supplying pure cultures of trichostrongyle larvae.

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