Studies on the life-history of Bunostomum phlebotomum (Railliet, 1900), a hookworm parasite of cattle

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 192-201 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Infective Larva ◽  
Stage Larva ◽  
Fourth Stage ◽  
Larval Stages ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Time Required ◽  
Cutaneous Blood ◽  
Fourth Stage Larva

A description is given of the processes of copulation, formation of the egg and spermatozoon, cleavage, embryogeny and hatching in B. phlebotomum. These processes were found to be essentially similar to those in other strongyle nematodes.The anatomy of the first three larval stages is described and the observations of Conradi & Barnette (1908) and Schwartz (1924) were largely confirmed.Penetration of the skin of calves by the infective larva was observed histologically. The larvae were found to have reached the dermis within 30 min. and to have penetrated the cutaneous blood vessels within 60 min. of application to the skin. The larvae were found in the lung where the third ecdysis was in progress 10 days after penetration of the skin. A description is given of the growth of the third-stage larva in the lung, the changes which take place during the third ecdysis, and the anatomy of the fourth-stage larva.The fourth-stage larvae exsheath in the lungs and travel to the intestine. After a period of growth in which sexual differentiation takes place, the fourth ecdysis occurs and the adult parasite emerges. The time required for the attainment of maturity was found to be somewhere between 30 and 56 days after penetration of the skin.This paper was written at the Ministry of Agriculture and Fisheries Veterinary Laboratories, Wey-bridge, and the writer would like to express his gratitude to the Director, Prof. T. Dalling, also to Dr W. R. Wooldridge, chairman of the Council of the Veterinary Educational Trust for their help and encouragement. The writer's thanks are also due to Dr H. A. Baylis, Prof. R. T. Leiper and Dr E. L. Taylor for their advice and help on technical points, and to Mr R. A. O. Shonekan, African laboratory assistant, for his able co-operation.

Observations on the Life History of Triodontophorus tenuicollis, a Nematode Parasite of the Horse

1925 ◽  
Vol 3 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R. J. Ortlepp
Keyword(s):  
Buccal Capsule ◽  
Stage Larva ◽  
Fourth Stage ◽  
Free Living ◽  
Larval Stages ◽  
Third Stage ◽  
History Of ◽  
Last Stage ◽  
Marked Resistance ◽  
Fourth Stage Larva

1. During the free-living development the larvæ of Triodontophorus tenuicollis undergo two moults separating three larval stages, the last stage remaining ensheathed in the cuticule of the previous stage.2. The development takes about four days when the eggs are cultured in horse fæces and charcoal at 26° C.3. The infective or third stage larvæ are climbers, and also show a marked resistance to desiccation ; they can also withstand variations in temperature from – 8° C. to 60° C.4. They do not penetrate skin.5. Infection of the host is probably via the mouth during grazing.6. The fourth-stage larva is described. It is free in the lumen of the colon, possesses a well-marked larval buccal capsule and three stout and pointed œsophageal teeth. Sex differences are now present.7. The adult buccal capsule develops in the form of a vesicle round the base of the larval buccal capsule.8. The probable mode of its parasitic development is given.9. A fourth-stage larva, probably that of either T. brevicauda or T. serratus, is described.

Effects of methotrexate on the parasitic development of the nematode Dictyocaulus viviparus (Metastrongylidae), and on the immune response of infected guinea-pigs

Parasitology ◽  
1971 ◽  
Vol 63 (1) ◽  
pp. 145-156 ◽  
Author(s):  
R. J. M. Wilson
Keyword(s):  
Immune Response ◽  
Developmental Stages ◽  
Stage Larva ◽  
Immune Mechanism ◽  
Fourth Stage ◽  
Dictyocaulus Viviparus ◽  
The Third ◽  
Effective Immune Response ◽  
Early Developmental ◽  
Fourth Stage Larva

Methotrexate inhibited the growth of D. viviparus by acting either on the moult from the third- to the fourth-stage larva or on the growth of fourth-stage larva itself. Despite these effects of the drug, the early developmental stages of the worms primed the immune mechanism of the host; the inductive phase of antibody production was completed in less than 5 days. An effective immune response, however, was blocked by the continued presence of methotrexate which resulted in delayed elimination of a superinfection and the absence of anaphylactic antibody in the serum. Immune elimination appeared to require a quantitative threshold of worm antigen and host antibody.This work was made possible by the generous supply of infective helminth material from Messrs Allen and Hanbury Ltd, Ware, Herts. I should also like to thank Dr J. H. Humphrey and Dr S. R. Smithers of N.I.M.R. for their helpful discussions.

THE LIFE HISTORY OF MOLINEUS BARBATUS CHANDLER, 1942

1961 ◽  
Vol 39 (5) ◽  
pp. 579-587 ◽  
Author(s):  
S. P. Gupta
Keyword(s):  
Life History ◽  
Small Intestine ◽  
Life Cycle ◽  
Stage Larva ◽  
Highly Pathogenic ◽  
Experimental Host ◽  
The Third ◽  
Third Stage ◽  
History Of

Using the ferret as an experimental host, the life cycle of Molineus barbatus was shown to be direct. All stages are described. The third-stage larva infects the host orally or percutaneously and subsequent stages develop in the mucosa of the small intestine. The male matures earlier than the female and eggs are laid in 8 to 13 days after infection. The parasite is highly pathogenic to ferrets but apparently less so to skunks and racoons.

The life history of Hysterothylacium analarum Rye and Baker, 1984 (Nematoda: Anisakidae) in Lepomis gibbosus (Pisces: Centrarchidae) in southern Ontario, Canada

1992 ◽  
Vol 70 (8) ◽  
pp. 1576-1584
Author(s):  
Leslie A. Rye ◽  
Michael R. Baker
Keyword(s):  
Seasonal Pattern ◽  
Late Summer ◽  
Intestinal Lumen ◽  
Lepomis Gibbosus ◽  
Fourth Stage ◽  
Larval Stages ◽  
Second Stage ◽  
Third Stage ◽  
History Of ◽  
Gravid Females

Larval stages of Hysterothylacium analarum are described from Lepomis gibbosus in Dawson Pond, Ontario (45°10′N, 78°50′W). Second-stage larvae were easily distinguished from all other stages by the presence of a conical boring tooth. Third-stage larvae lacked both a boring tooth and lips. Fourth-stage larvae had well-developed lips. The ratio of ventricular appendage length to intestinal caecum length varied greatly between larval stages and adults. Prevalence and intensity of larval stages and adult H. analarum showed a distinct seasonal pattern, with one generation of adult worms per year. In spring, third-stage larvae left nodules on the intestinal serosa of L. gibbosus and migrated to the intestinal lumen, where they rapidly moulted to the fourth-stage and then to adult worms. Eggs collected from gravid females developed to second stage larvae in approximately 5 days under laboratory conditions. In natural infections in the late summer second-stage larvae were found in nodules on the serosa and in the mesentery. Larvae apparently moulted to the third stage and overwintered in the nodules as third-stage larvae.

The life history and development ofAmplicaecum robertsi, an ascaridoid nematode of the carpet python (Morelia spilotes variegatus). I. Morphology and functional significance of larval stages

Parasitology ◽  
1963 ◽  
Vol 53 (1-2) ◽  
pp. 7-38 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Functional Significance ◽  
Structural Changes ◽  
Adult Stage ◽  
Reproductive Organs ◽  
Fourth Stage ◽  
Laboratory Rats ◽  
Larval Stages ◽  
Second Stage ◽  
The Third ◽  
Third Stage

The development ofAmplicaecum robertsihas been followed from the egg to the adult stage using laboratory mice and rats as intermediate hosts. The eggs were found to be resistant to desiccation and would develop under water; they were infective to mice after culturing for 18 days after removal from the uterus.Completion of the first moult occurred after hatching of the eggs in the intestine. Within 6 hr. of infection second-stage larvae had reached the liver. They also appeared in the lungs and carcass, but after 2 days were mostly confined to the liver.At 5–7 days after infection larvae underwent a period of lethargy followed by the second moult and the third-stage larvae commenced a period of growth reaching a length of 79 mm. at 28 weeks after infection in the liver of mice. In rats the growth of the larvae was slower for the first 2 months, but eventually they reached more or less the same proportions as in mice. The intestinal caecum appeared at a length of 3–4 mm., but there was no development of the reproductive organs throughout the third stage and no evidence of the third moult in rodents.Fifty carpet snakes were autopsied and searched for larvae and adults ofA. robertsi; in two snakes third-stage larvae were found in the aorta; in one snake the third moult was observed in the wall of the stomach and oesophagus; in three snakes the fourth moult was observed in the wall of the stomach; in twenty-six snakes adults were found.Experimental infection of laboratory-reared carpet snakes showed that infection with embryonated eggs resulted in second-stage larvae in the tissues which did not develop further. Infection with third-stage larvae, resulted in two distinct migratory patterns depending upon the maturity of the larvae administered. Larvae from the liver of laboratory rats which had been infected less than 12 weeks previously, migrated to various tissues, especially the aorta, of the snake, where they remained coiled in cysts filled with clotted blood for periods up to 112 days. Growth occurred within these cysts, but no evidence of moulting was observed. In contrast, larvae from the liver of laboratory rats infected 12 weeks or more previously, and from mice infected for 8 weeks or more, underwent the third moult in the wall of the oesophagus and stomach of the snake.With the onset of the fourth stage, the development of the reproductive organs became evident and continued during the fourth stage. It appeared that the fourth stage may occur in two phases, possibly depending on the size of the third-stage larva at the time of ingestion. Some experimental infections indicated that third-stage larvae may give rise to attached fourth stage larvae, probably capable of active growth. Other observations indicated that fourth-stage larvae may remain encapsulated in the wall of the stomach or oesophagus until sex differentiation is completed, after which the fourth moult occurs and the adult parasite emerges, leaving two sheaths of the same length within the capsule.The functional significance of each of the larval stages is discussed and it was concluded:—that the first-stage larva is one of tissue differentiation, whereby development proceeds to the infective stage; that the second stage represents a migratory phase without structural changes; that the third stage represents a growth phase, characterized by considerable increase in size, but without further radical changes in differentiation.In contrast, the fourth stage is characterized by absence of growth, inability to migrate, and by marked structural changes in the reproductive organs, whereby the sexes are differentiated. Evidently this development may take place while the fourth stage is attached to the wall of the stomach or oesophagus, or while the larva remains in the capsule in a state of quiescence.The fourth moult may occur in the attached state, but usually occurs within the capsule. After it is completed, the adult may remain for an indefinite period within the capsule with the two sheaths of the third and fourth stage. The emergence of the adult worms may be influenced by the arrival of food in the stomach. Once this phase is initiated, both growth and reproductive activity ensue during the adult stage.This work was financed by a research grant from the University of Queensland. The writer wishes to acknowledge the valuable assistance of Miss Ann Pritchard.

The development of Haemonchus contortus in vitro: II. The effect of disulphide-reducing and sulphydryl-blocking reagents on the rate of development to the fourth-stage larvae

Parasitology ◽  
1970 ◽  
Vol 60 (1) ◽  
pp. 123-135 ◽  
Author(s):  
C. J. Mapes
Keyword(s):  
Haemonchus Contortus ◽  
Reduced Glutathione ◽  
Stage Larva ◽  
Fourth Stage ◽  
Rate Of Development ◽  
The Third ◽  
Short Period ◽  
Third Stage ◽  
Before And After

Cysteine (20–100 mM) and reduced glutathione (20–80 mM) potentiated the development of the exsheathed third-stage larva of Haemonchus contortus to the fourth stage. The potentiating effect of cysteine was greatest during the short period before and after the exsheathment of the third-stage larva. Two hundred mM cysteine and 1 mM p–chloro-benzoate inhibited development. This inhibition was reversible. Ten mM iodoacetate and 0·5 and 5 mM n–ethyl-maleimide inhibited development of the larvae. The larvae appeared to be most susceptible to the inhibiting effects of these reagents during the period of development approaching the third moult. Development was either little affected or potentiated, when larvae were incubated with these reagents for short periods immediately after exsheathment.

scholarly journals Is There Daily Growth Hysteresis versus Vapor Pressure Deficit in Cherry Fruit?

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 131
Author(s):  
Matteo Zucchini ◽  
Arash Khosravi ◽  
Veronica Giorgi ◽  
Adriano Mancini ◽  
Davide Neri
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Fruit Growth ◽  
Hysteresis Curve ◽  
Growth Stages ◽  
Fourth Stage ◽  
The Third ◽  
Third Stage ◽  
Rainy Days ◽  
Clockwise Hysteresis

The growth of cherry fruit is generally described using a double sigmoid model, divided into four growth stages. Abiotic factors are considered to be significant components in modifying fruit growth, and among these, the vapor pressure deficit (VPD) is deemed the most effective. In this study, we investigated sweet cherry fruit growth through the continuous, hourly monitoring of fruit transversal diameter over two consecutive years (2019 and 2020), from the beginning of the third stage to maturation (forth stage). Extensometers were used in the field and VPD was calculated from weather data. The fruit growth pattern up to the end of the third stage demonstrated three critical steps during non-rainy days: shrinkage, stabilization and expansion. In the third stage of fruit growth, a partial clockwise hysteresis curve of circadian growth, as a response to VPD, appeared on random days. The pattern of fruit growth during rainy days was not distinctive, but the amount and duration of rain caused a consequent decrease in the VPD and indirectly boosted fruit growth. At the beginning of the fourth stage, the circadian growth changed and the daily transversal diameter vs VPD formed fully clockwise hysteresis curves for most of this stage. Our findings indicate that hysteresis can be employed to evaluate the initial phenological phase of fruit maturation, as a fully clockwise hysteresis curve was observable only in the fourth stage of fruit growth. There are additional opportunities for its use in the management of fruit production, such as in precision fruit farming.

Morphological description of the pupa and redescription of the adults and larva of Culex (Culex) apicinus Philippi (Diptera: Culicidae)

Zootaxa ◽  
2008 ◽  
Vol 1941 (1) ◽  
pp. 31-42 ◽  
Author(s):  
GUSTAVO CARLOS ROSSI ◽  
MAGDALENA LAURITO ◽  
WALTER RICARDO ALMIRÓN
Keyword(s):  
Species Distribution ◽  
Male Genitalia ◽  
Stage Larva ◽  
Morphological Description ◽  
Fourth Stage ◽  
Available Information ◽  
First Time ◽  
Fourth Stage Larva

The adult, fourth-stage larvae and the male genitalia of Culex (Culex) apicinus Philippi is redescribed. The pupa is described for the first time. The male genitalia, pupa and fourth-stage larva are illustrated. The available information on the taxonomy and distribution of the species is also included, extending the species distribution in Argentina. Bionomics and distributional data are provided for Culex apicinus.

The factors associated with the length of the third stage of labour: A descriptive-analytical study

2021 ◽  
Vol 17 ◽  
Author(s):  
Mansoureh Refaei ◽  
Soodabeh Aghababaei ◽  
Mansoureh Yazdkhasti ◽  
Farideh Kazemi ◽  
Fatemeh Farahmandpour
Keyword(s):  
Cross Sectional Study ◽  
Study Data ◽  
Cross Sectional ◽  
Factors Associated ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Mother’S Age ◽  
And Gender ◽  
The Relationship

Background: Several risk factors have been identified for postpartum hemorrhage, one of which being the duration of the third stage of labour. This stage refers to the interval between the expulsion of the fetus to the expulsion of the placenta. Some bleeding occurs in this stage due to the separation of the placenta Objective: This study aimed to identify the factors associated with the length of the third stage of labour. Methods: In this cross-sectional study, 300 women hospitalized for vaginal birth were selected via convenience sampling. The study data were collected using a researcher-made questionnaire. Then, the data were analyzed using univariate and multivariate linear regression analyses. Results: The mean (SD) age of the participants was 26.41 (6.26) years. Investigation of the relationship between the study variables and the time of placental separation indicated that a minute increase in the length of membranes rupture caused a 0.003minute decrease in the time of placental separation. However, this time increased by 2.75, 6.68, and 2.86 minutes in the individuals without the history of abortion, those with the history of stillbirth, and those who had not received hyoscine, respectively. The results of multivariate analysis indicated that suffering from preeclampsia or hypertension, history of stillbirth, not receiving hyoscine, and not receiving misoprostol increased the length of the third stage by 4.40, 8.55, 2.38, and 6.04 minutes, respectively. Conclusion: Suffering from preeclampsia and having the history of stillbirth increased and using hyoscine and misoprostol decreased the length of the third stage of labour. However, no significant relationship was found between the length of the third stage of labour and mother’s age, gestational age, parity, mother’s body mass index, mother’s chronic disorders, history of manual placenta removal, length of the first and second stages, membranes rupture, induction, amount of oxytocin after delivery, and infant’s weight and gender.

RUSSIAN DIASPORA. SUMMATION AND RESEARCH PROSPECTS

2020 ◽  
pp. 130-143
Author(s):  
Irina V. Sabennikova ◽  
Keyword(s):  
Soviet Union ◽  
Scientific Research ◽  
Soviet Period ◽  
The Third ◽  
The Soviet Union ◽  
Third Stage ◽  
Archival Documents ◽  
Significant Phenomenon ◽  
History Of ◽  
Methodological Principles

The historiography of any historically significant phenomenon goes through several stages in its development. At the beginning − it is the reaction of contemporaries to the event they experienced, which is emotional in nature and is expressed in a journalistic form. The next stage can be called a retrospective understanding of the event by its actual participants or witnesses, and only at the third stage there does appear the objective scientific research bringing value-neutral assessments of the phenomenon under study and belonging to subsequent generations of researchers. The history of The Russian Diaspora and most notably of the Russian post-revolutionary emigration passed to the full through all the stages of the issue historiography. The third stage of its studying dates from the late 1980s and is characterized by a scientific, politically unbiased study of the phenomenon of the Russian emigration community, expanding the source base and scientific research methods. During the Soviet period in Russian historiography, owing to ideological reasons, researchers ‘ access to archival documents was limited, which is why scientific study of the history of the Russian Diaspora was not possible. Western researchers also could not fully develop that issue, since they were deprived of important sources kept in Russian archives. Political changes in the perestroika years and especially in the period after the collapse of the Soviet Union increased attention to the Russian Diaspora, which was facilitated by a change in scientific paradigms, methodological principles, the opening of archives and, as a result, the expansion of the source base necessary for studying that issue. The historiography of the Russian Diaspora, which has been formed for more than thirty years, needs to be understood. The article provides a brief analysis of the historiography, identifies the main directions of its development, the research problematics, and defines shortcomings and prospects.

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