The survival of desiccation by the free-living stages of Trichostrongylus colubriformis (Nematoda: Trichostrongylidae)

Parasitology ◽  
1982 ◽  
Vol 84 (3) ◽  
pp. 455-462 ◽  
Author(s):  
D. A. Wharton
Keyword(s):  
Relative Humidity ◽  
Prolonged Exposure ◽  
Infective Larva ◽  
Survival Times ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Second Stage ◽  
Infective Larvae

SummaryThe survival of the free-living stages of Trichostrongylus colubriformis under defined conditions of temperature and relative humidity was investigated. The survival of embryonated eggs was poor at 0, 33 and 54·5 % relative humidity (rel. hum.) at 20 °C but hatching occurred from a proportion of eggs even after exposure for 104 days to 76 and 98% rel. hum. at 20 °C. Second-stage larvae were desiccation-susceptible and were killed within 6 h even at 98% rel. hum. and 20 °C. Infective larvae, dried separately or in clumps, survived prolonged exposure to desiccation at 33–98% rel. hum. and 20 °C with 50% survival times of 58–164 days. Clump formation did not enhance survival in this range. Infective larvae also survived exposure to vacuum desiccation with 50% survival times of 8·8 h in clumps and 4·5 h when dried separately. The infective larva thus readily survives desiccation and may prove a useful model for the study of anhydrobiosis.

scholarly journals Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

2012 ◽  
Vol 21 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Raquel Abdallah da Rocha ◽  
Patrizia Ana Bricarello ◽  
Gilberto Pedroso da Rocha ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Dry Matter ◽  
Cynodon Dactylon ◽  
Larval Survival ◽  
Grass Species ◽  
Panicum Maximum ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Brachiaria Decumbens ◽  
Infective Larvae ◽  
Experimental Plots

This experiment aimed to assess the recovery of infective larvae (L3) of Trichostrongylus colubriformis from Brachiaria decumbens cv. Australiana, Cynodon dactylon cv. Coast-cross and Panicum maximum cv. Aruana. The experimental module comprised six plots, with two plots per herbage species. Larval survival was assessed from autumn to winter, under the effect of two herbage-paring heights (5 and 30 cm). TThe paring was carried out immediately before contamination with faces containing T. colubriformis eggs. The feces and herbage were collected at one, two, four, eight, 12 and 16 weeks after feces had been deposited in the experimental plots. In general, larvae were recovered from both herbage and feces until the 16th week. The longer persistence of these larvae in the environment was probably due to warmer temperatures. The number of L3 recovered from the pasture was not influenced by the height of plants, except for Brachiaria and Aruana herbage in the fourth week. Regarding the concentrations of larvae per kg of dry matter (L3/kg DM), recovery was higher from low pasture in all three herbage species. During the autumn, the development and survival of the T. colubriformis free-living stages were not affected by the different herbage species.

scholarly journals Strongyloses ratti and S. stercoralis: effects of cambendazole, thiabendazole and mebendazole in vitro

1986 ◽  
Vol 28 (2) ◽  
pp. 97-103 ◽  
Author(s):  
David I. Grove ◽  
Carolyn Northern
Keyword(s):  
The Other ◽  
Free Living ◽  
Second Stage ◽  
Infective Larvae ◽  
In Vitro Incubation ◽  
Living Adult

The effects of in vitro incubation of three henzimidazole anthelmintics, thiabendazole, mebendazole and cambendazole on Strongyloides were compared. No drug affected hatching of S. ratti eggs or the viability of infective larvae or parasitic adult worms, but all three inhibited moulting of S. ratti larvae. In addition, cambendazole, but not thiabendazole or mebendazole, impaired the viability of S. ratti first- and second-stage larvae. The three drugs had no effect on isolated S. stercorais free-living adult worms, but they all prevented development of S. stercoralis rhabditiform larvae. Thiabendazole and mebendazole had no effect on the infectivity of either S. ratti or S. stercoralis infective larvae, but infection with these worms was abrogated by prior incubation with cambendazole. These results indicate that cambendazole acts in a different manner to the other two drugs. Since it is active against larvae migrating through the tissues, it is potentially of much greater value than thiabendazole or mebendazole in the therapy of strongyloidiasis.

The Life-History of Syngamus trachealis (Montagu) v. Siebold, the Gape-Worm of Chickens

1923 ◽  
Vol 1 (3) ◽  
pp. 119-140 ◽  
Author(s):  
R. J. Ortlepp
Keyword(s):  
Sexual Maturity ◽  
Infective Larva ◽  
The Body ◽  
Infective Stage ◽  
Fourth Stage ◽  
Second Stage ◽  
Infective Larvae ◽  
Stage Of Development ◽  
History Of ◽  
Whole Life Cycle

(1) The female can and does lay eggs.(2) The eggs in the body of living worms do not develop beyond the 16-celled stage.(3) The eggs passed in the fæces of chickens are in the same stage of development as those in the uteri of the adult.(4) The eggs take about a week to develop and produce infective larva?, when cultured in well aerated water at a. temperature of about 25°C.(5) The embryos undergo only one moult before reaching the infective stage.(6) The second stage or infective larvae are generally ensheathed. They are non-climbers, do not penetrate the skin, and cannot resist dessication.(7) In the body of the host the larvae soon reach the lungs, where they grow considerably in size and undergo two further moults.(8) The final or fourth stage larvae are reached in about five days after infection.(9) The larvae then copulate and migrate into the trachea where they attain sexual maturity in from 10 to 14 days later.(10) The whole life cycle is completed within a month.

STUDIES ON STRONGYLOIDES OF PRIMATES: II. FACTORS DETERMINING THE "DIRECT" AND THE "INDIRECT" MODE OF LIFE

1958 ◽  
Vol 36 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Premvati
Keyword(s):  
Life Cycle ◽  
Infective Larva ◽  
Optimum Conditions ◽  
Female Larva ◽  
Free Living ◽  
Adverse Conditions ◽  
Infective Larvae ◽  
Mode Of Life

Under optimum conditions Strongyloides fülleborni has an indirect life cycle but under adverse conditions, only infective larvae and males are developed. Adverse factors such as pH and consistency of media, absence of food, and unsuitable temperatures appear to act directly on the first-stage rhabditiform larvae developed from the eggs of parasitic females. The potential female larva alone becomes an infective larva, the potential male being unaffected. There is a single free-living generation and all eggs laid by free-living females develop directly into infective larvae. The infective larvae developed directly or indirectly can develop only into parthenogenetic females.

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.

scholarly journals Retrieval of Trichostrongylus colubriformis infective larvae from grass contaminated in winter and in spring

2014 ◽  
Vol 23 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Raquel Abdallah da Rocha ◽  
Patrizia Ana Bricarello ◽  
Gilberto Pedroso da Rocha ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Forage Grasses ◽  
Trichostrongylus Colubriformis ◽  
Fecal Samples ◽  
Infective Larvae ◽  
Retrieval Rate ◽  
Experimental Plots

The survival of infective larvae (L3) of Trichostrongylus colubriformis was evaluated on Brachiaria, Coast-cross and Aruana forage grasses. Feces of sheep parasitized exclusively by T. colubriformis were deposited in winter and spring on experimental plots whose grasses were cut at two heights: 5 cm and 30 cm. One, two, four, eight, 12 and 16 weeks after depositing the feces, fecal and forage samples were collected for the retrieval and quantification of L3. Retrieval of L3 from feces and forage was negligible in winter due to the dry weather, although a few larvae were retrieved in the last larval collections. However, L3 retrieval from fecal samples was greater in spring, especially two weeks after feces were deposited on 30 cm high grasses. At this time, the L3 retrieval rate from the three forage grasses differed significantly (P <0.05), with Aruana grass showing the highest average L3 retrieval rate, followed by Coast-cross and Brachiaria. In conclusion, the winter drought proved very unfavorable for the presence of L3 in the environment, and the microclimate of Aruana pastureland was generally the most favorable for the retrieval of infective larvae.

Sign in / Sign up

Export Citation Format

Share Document