THE LIFE HISTORY OF MOLINEUS BARBATUS CHANDLER, 1942

1961 ◽  
Vol 39 (5) ◽  
pp. 579-587 ◽  
Author(s):  
S. P. Gupta

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.

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 192-201 ◽  
Author(s):  
J. F. A. Sprent

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.


1957 ◽  
Vol 5 (2) ◽  
pp. 188 ◽  
Author(s):  
MJ Mackerras

First-stage larvae of Aelurostrongylus abstrusus (Railliet) developed readily in the garden slug, Agriolimax laevis (Muller), two moults occurring in this host. When infected slugs were eaten by a cat, the third-stage larvae migrated at once to the lungs, where they underwent the third and fourth moults. The prepatent period in the cat was about 39 days. When infected slugs were fed to laboratory-bred mice, the third-stage larvae were not digested, but congregated in great numbers in the gastro-splenic ligament, forming minute yellowish cysts. They were also recovered in small numbers from other parts of the body. Third-stage larvae survived unchanged in mice for 12 weeks, and probably would survive for longer periods. Mice were regarded as important auxillary hosts. The minute adult worms were found in the bronchioles of the cat. They were always very difficult to locate. The eggs were laid in the alveoli, forming a characteristic pattern of small, solid nodules scattered throughout the lung tissue.


1974 ◽  
Vol 48 (4) ◽  
pp. 293-310 ◽  
Author(s):  
C. K. Ow-Yang

AbstractAdults ofHepatojarakus malayaelive in the bile duct of many species ofRattusin Peninsular Malaysia, ine life cycle of this parasite was studied in laboratory white rats. Eggs were passed out with the faeces at the early morula stage and hatched within 15 hours, giving rise to the first stage larvae. These developed to the third stage in about 36 hours and these were given orally to new rats in experimental infections. The migratory route of the larvae from the gut to the liver was traced. Penetration into the host appeared to be confined mainly to the fundic wall of the stomach. The larvae presumably followed the portal route to the uver. Here the final moult occurred before the young adults moved into the biliary passages.


1917 ◽  
Vol 8 (2) ◽  
pp. 121-123 ◽  
Author(s):  
D. Keilin

It has been well known since the studies of Taschenberg (1864–1872) that the larvae of Leptohylemyia coarctata, Fall., attack wheat and rye. The damage due to this fly has been observed many times in almost all European countries, and many papers have been devoted to its life-history. Of these papers the most important are those of E. Ormerod (1882–1895), S. Rostrup (1905–1911), T. Hedlund (1906- 1907), P. Marchal (1909) and finally the recent work of Kurdjumov (1914).


2021 ◽  
Vol 17 ◽  
Author(s):  
Mansoureh Refaei ◽  
Soodabeh Aghababaei ◽  
Mansoureh Yazdkhasti ◽  
Farideh Kazemi ◽  
Fatemeh Farahmandpour

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.


Author(s):  
Irina V. Sabennikova ◽  

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.


Zootaxa ◽  
2017 ◽  
Vol 4290 (3) ◽  
pp. 571
Author(s):  
MARIO G. IBARRA-POLESEL ◽  
NESTOR G. VALLE ◽  
JHON C. NEITA-MORENO ◽  
MIRYAM P. DAMBORSKY

Phileurus valgus (Olivier) (Coleoptera: Scarabaeidae: Dynastinae: Phileurini) is a common species widely distributed from the southern United States to Argentina and the West Indies. In this work the immature stages are described and illustrated based on specimens from Argentina. A key to the known third-stage larvae of New World Phileurini species is provided and updated. Notes on the life cycle and natural history are also included. 


Parasitology ◽  
1958 ◽  
Vol 48 (1-2) ◽  
pp. 70-88 ◽  
Author(s):  
M. J. Clarkson

The life cycle and pathogenicity of a strain of Eimeria isolated in Great Britain from turkey poults by single cell inoculation are described and, using the criteria laid down by Tyzzer, the species is identified as E. adenoeides.The life cycle is of the same general pattern as in other Eimeria species, consisting of two asexual and one sexual generations.The organism is highly pathogenic for young poults, a dose of 200,000 oocysts producing 100 % mortality in 3-week-old birds and smaller doses causing reduced weight gain. Birds 11 weeks old resisted a dose of 3 million oocysts.The gross and microscopic pathology of the infection is described. No changes were found in the blood picture.


Author(s):  
J. B. Brown-Gilpin

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.


1953 ◽  
Vol 31 (4) ◽  
pp. 351-373 ◽  
Author(s):  
Liang-Yu Wu

A cause of swimmer's itch in the lower Ottawa River is Trichobilharzia cameroni sp. nov. Its life cycle has been completed experimentally in laboratory-bred snails and in canaries and ducks, and the various stages are described. The eggs are spindle-shaped. The sporocysts are colorless and tubular. Mother sporocysts become mature in about a week. The younger daughter sporocyst is provided with spines on the anterior end and becomes mature in about three weeks. The development in the snail requires from 28 to 35 days. A few cercariae were found to live for up to 14 days at 50 °C., although their life at 16° to 18 °C. was about four days. Cercariae kept at room temperature for 60 to 72 hr. were found infective. The adults become mature in canaries and pass eggs in about 12 to 14 days. Physa gyrina is the species of snail naturally infected. It was found in one case giving off cercariae for five months after being kept in the laboratory. Domestic ducks were found to become infected until they were at least four months old, with the parasites developing to maturity in due course; no experiments were made with older ducks. Furthermore, miracidia were still recovered from the faeces four months after the duck had been experimentally infected, and it is suggested that migratory birds are the source of the local infection.


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