THE LIFE CYCLE OF FASCIOLOIDES MAGNA (BASSI, 1875), THE LARGE LIVER FLUKE OF RUMINANTS, IN CANADA: WITH OBSERVATIONS ON THE BIONOMICS OF THE LARVAL STAGES AND THE INTERMEDIATE HOSTS, PATHOLOGY OF FASCIOLOIDIASIS MAGNA, AND CONTROL MEASURES

1935 ◽  
Vol 12 (2) ◽  
pp. 177-215 ◽  
Author(s):  
W. E. Swales
Keyword(s):  
Life Cycle ◽  
Historical Review ◽  
Tissue Reaction ◽  
Control Measures ◽  
Histopathological Study ◽  
Intermediate Hosts ◽  
Fascioloides Magna ◽  
Larval Stages ◽  
History Of ◽  
And Control

The life history of Fascioloides magna in Canada has been elucidated, the intermediate hosts being two fresh-water gastropods, Fossaria parva (Lea) and Stagnicola palustris nuttalliana (Lea). The morphology and bionomics of the egg and larval stages are described, particular attention being given to the nonparasitic stages. The ecology of the gastropod hosts in Canada is briefly described.A histopathological study of the lesion in definitive hosts reveals that this parasite in large Bovidae causes a severe tissue reaction. The lesion in these animals is generally in the form of a closed fibrous cyst from which eggs are unable to pass, and thus the life cycle cannot be completed. In Cervidae, the cavity in the liver is connected directly with the bile duct system, and there is a free egress of ova. From these facts it is inferred that this parasitic disease can only occur in the presence of Cervidae.Laboratory animals have been artificially infested with maritae, thus extending the host records of the trematode.A brief historical review, a summary of the present knowledge of distribution and definitive hosts affected, and a description of the control measures, are included.

The life-history and control of Hapatesus hirtus Candeze (Coleoptera: Elateridae) in Victoria

1991 ◽  
Vol 42 (5) ◽  
pp. 827 ◽  
Author(s):  
PA Horne ◽  
JA Horne
Keyword(s):  
Life History ◽  
Field Trials ◽  
Soil Samples ◽  
Control Measures ◽  
Potato Tubers ◽  
Larval Stages ◽  
Complete Development ◽  
History Of ◽  
And Control ◽  
Potato Crops

The incidence and life-history of potato wireworm, Hapatesus hirtus Candeze, in Victorian potato crops were studied, and insecticidal control measures assessed. Larval stages were present and active throughout the year. Ten larval instars were identified, probably requiring several years to complete development. Egg development occurred in October-November and the most likely timing of oviposition was December. The relative numbers of larval H. hirtus detected in soil samples, pre-planting baits and harvested tubers are presented. Baiting with halves of potatoes provided an efficient means of detecting areas likely to suffer wireworm damage. One formulation of chlorpyrifos ('Lorsban') was effective in reducing damage to, and larval numbers in, potatoes in field trials. The granular formulation of tefluthrin and the controlled release chlorpyrifos were not effective in protecting potato tubers.

scholarly journals Times to Key Events in the Course of Zika Infection and their Implications for Surveillance: A Systematic Review and Pooled Analysis

2016 ◽  
Author(s):  
Justin Lessler ◽  
Cassandra T. Ott ◽  
Andrea C. Carcelen ◽  
Jacob M. Konikoff ◽  
Joe Williamson ◽  
...  
Keyword(s):  
Systematic Review ◽  
Blood Supply ◽  
Zika Virus ◽  
Blood Donation ◽  
Case Reports ◽  
Fold Increase ◽  
Pooled Analysis ◽  
Control Measures ◽  
History Of ◽  
And Control

Background Evidence suggests that Zika virus has driven a 10-fold increase in babies born with microcephaly in Brazil, prompting the WHO to declare a Public Health Emergency of International Concern. However, little is known about the natural history of infection. These data are critical for implementation of surveillance and control measures such as protecting the blood supply. Methods We conducted a systematic review and pooled analysis to estimate the distribution of times from Zika infection to symptom onset, seroconversion, and viral clearance, and analyzed their implications for surveillance and blood supply safety. Results Based on 25 case reports, we estimate the median incubation period of Zika virus infection is 5.9 days (95% CI: 4.4-7.6), and that 95% of cases will develop symptoms by 11.1 days post-infection (95% CI: 7.6-18.0). On average seroconversion occurs 9.0 days (95% CI, 7.0-11.6) after infection, and virus is detectable in blood for 9.9 days (95% CI: 6.8-21.4). In 5% of cases detectable virus persists for over 18.9 days (95% CI: 12.6-79.5). The baseline (no screening) risk of a blood donation being infected with Zika increases by approximately 1 in 10,000 for every 1 per 100,000 person-days increase in Zika incidence. Symptom based screening reduces this by 7% (RR 0.93, 93% CI 0.86-0.99), and antibody screening by 29% (RR 0.71, 95% CI: 0.28-0.88). Conclusions Symptom or antibody-based surveillance can do little to reduce the risk of Zika contaminated blood donations. High incidence areas may consider PCR testing to identify lots safe for use in pregnant women.

scholarly journals Serological Investigations of Brucellosis in Cattle, Farmers and Veterinarians in the Kars District of Turkey

2008 ◽  
Vol 77 (1) ◽  
pp. 117-121 ◽  
Author(s):  
S. Otlu ◽  
M. Sahin ◽  
H. I. Atabay ◽  
A. Unver
Keyword(s):  
Control Measures ◽  
Serum Samples ◽  
Serological Tests ◽  
Significant Difference ◽  
High Prevalence ◽  
History Of ◽  
And Control

The prevalence of brucellosis was investigated in cattle, farmers and veterinarians in the Kars district of Turkey between 2004 - 2006. In order to achieve this, a total of 407 serum samples of cattle from 27 herds having history of abortions were examined for Brucella antibodies by RBPT and SAT. In addition, the sera collected from 246 farmers (130 males and 116 females) and 28 veterinarians in the same district were analysed serologically by RBPT, SAT and ELISA. Of the cattle sera analysed, 134 (32.92%) and 141 (34.64%) were determined as positive by RBPT and SAT, respectively. Thirty-two (13%), 35 (14.22%) and 44 (17.88%) of the farmers' sera were found positive for brucellosis by RBPT, SAT and ELISA, respectively. There was no significant difference between sexes for Brucella seropositivity. Of the 28 sera from veterinarians, 13 (46.42%) were positive by the three serological tests. The high prevalence of brucellosis both in cattle and humans suggests that brucellosis is common in this area. Preventive and control measures should be implemented and pursued more strictly to reduce and/or eradicate brucellosis from the area.

Life cycle studies on two Digenea, Paradistomum geckonum (Dicrocoeliidae) and Mesocoelium sociale (Mesocoeliidae), in geckonid lizards from Indonesia

1987 ◽  
Vol 65 (10) ◽  
pp. 2491-2497 ◽  
Author(s):  
Murray J. Kennedy ◽  
L. M. Killick ◽  
M. Beverley-Burton
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Intermediate Hosts ◽  
Larval Stages ◽  
Hemidactylus Frenatus ◽  
Pulmonate Gastropod ◽  
First Intermediate Host

Life cycle studies of Paradistomum geckonum (Dicrocoeliidae) were attempted experimentally. The pulmonate gastropod Lamellaxis gracilis served as the first intermediate host; geckonid lizards (Cosymbotus platyurus, Gehyra mutilata, and Hemidactylus frenatus) served as definitive hosts. The life cycle of Mesocoelium sociale (Mesocoeliidae) was studied in naturally infected first intermediate hosts (L. gracilis, Huttonella bicolor) and experimentally in geckonid definitive hosts (C. platyurus, G. mutilata, and H. frenatus). Some naturally infected L. gracilis were infected concurrently with larval stages of both digeneans. Second intermediate hosts, presumed to be arthropods, were experimentally unnecessary. Metacercariae of P. geckonum were not found. Cercariae of M. sociale formed encysted metacercariae in the same individual snails.

Observations on the suitability and importance of the domestic intermediate hosts of Echinococcus granulosus in Uttah Pradesh, India

1989 ◽  
Vol 63 (1) ◽  
pp. 39-45 ◽  
Author(s):  
M. Irshadullah ◽  
W. A. Nizami ◽  
C. N. L. Macpherson
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Echinococcus Granulosus ◽  
Frequency Distribution ◽  
Host Species ◽  
Control Measures ◽  
The Other ◽  
Hydatid Cysts ◽  
Intermediate Hosts ◽  
Cyst Size

ABSTRACTThe present study investigated the suitability and importance of buffaloes, camels, sheep, goats and pigs in maintaining the life-cycle of Echinococcus granulosus in Aligarh, India. A total of 565 (36%) of 1556 buffaloes, 20 (2%) of 1208 goats, 5 (1%) of 559 pigs, 6 (6%) of 109 sheep and two of three camels were found to harbour hydatid cysts. The frequency distribution of the hydatid cysts in each intermediate host species was over-dispersed and in buffaloes cyst fertility increased with increasing cyst size. Of 2171, 95 and four buffalo, goat, and camel cysts examined 327 (15%), two (2%) and three cysts respectively were fertile. No pig or sheep cysts were found to contain protoscoleces. The unfenced buffalo abattoir and the large number of dogs allowed access to the abattoir coupled to the number of buffaloes slaughtered in comparison to the other potential hosts, indicates that the buffalo is the most significant host for maintaining the life-cycle of the parasite in this area of India. Applicable control measures for the region are suggested.

scholarly journals The History of Rabies in Trinidad: Epidemiology and Control Measures

2017 ◽  
Vol 2 (3) ◽  
pp. 27 ◽  
Author(s):  
Janine Seetahal ◽  
Alexandra Vokaty ◽  
Christine Carrington ◽  
Abiodun Adesiyun ◽  
Ron Mahabir ◽  
...  
Keyword(s):  
Control Measures ◽  
History Of ◽  
And Control

Parasite life-cycle studies: a plea to resurrect an old parasitological tradition

2017 ◽  
Vol 91 (6) ◽  
pp. 647-656 ◽  
Author(s):  
I. Blasco-Costa ◽  
R. Poulin
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Integrative Taxonomy ◽  
Life Cycles ◽  
Intermediate Hosts ◽  
Parasite Life Cycle ◽  
Quantitative Evidence ◽  
Research Areas ◽  
Food Web Ecology ◽  
And Control

AbstractMany helminth taxa have complex life cycles, involving different life stages infecting different host species in a particular order to complete a single generation. Although the broad outlines of these cycles are known for any higher taxon, the details (morphology and biology of juvenile stages, specific identity of intermediate hosts) are generally unknown for particular species. In this review, we first provide quantitative evidence that although new helminth species are described annually at an increasing rate, the parallel effort to elucidate life cycles has become disproportionately smaller over time. We then review the use of morphological matching, experimental infections and genetic matching as approaches to elucidate helminth life cycles. Next we discuss the various research areas or disciplines that could benefit from a solid knowledge of particular life cycles, including integrative taxonomy, the study of parasite evolution, food-web ecology, and the management and control of parasitic diseases. Finally, we end by proposing changes to the requirements for new species descriptions and further large-scale attempts to genetically match adult and juvenile helminth stages in regional faunas, as part of a plea to parasitologists to bring parasite life-cycle studies back into mainstream research.

scholarly journals Almond Replant Disease and Its Management with Alternative Pre-Plant Soil Fumigation Treatments and Rootstocks

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 869-876 ◽  
Author(s):  
G. T. Browne ◽  
J. H. Connell ◽  
S. M. Schneider
Keyword(s):  
Methyl Bromide ◽  
Prunus Dulcis ◽  
Soil Fumigation ◽  
Control Measures ◽  
Plant Soil ◽  
Replant Disease ◽  
Almond Trees ◽  
History Of ◽  
And Control ◽  
Conducive Soil

Trials were conducted in orchards near Chico, CA and microplots near Parlier, CA to examine symptoms and control measures for a replant disease (RD) on almond (Prunus dulcis). In the orchard trials, areas with a recent history of severe RD were cleared, given soil fumigation treatments in the fall, and replanted with almond trees on various rootstocks the following winter. The replants in nonfumigated soil developed severe RD (stunting, wilting, chlorosis, defoliation) by the following summer, while those in most fumigated treatments remained healthy. Trees in nonfumigated soil developed smaller trunk diameters and fewer healthy roots ≤1 mm diameter, compared with the healthy trees. Almond developed RD on all rootstocks evaluated (Marianna 2624, Lovell, and Nemaguard), but the trees on Marianna 2624 were the most severely affected. Pre-plant tree-site (spot) fumigation treatments with methyl bromide (MB), chloropicrin (CP), 1,3-dichloropropene (1,3-D), 1,3-D + CP, iodomethane, and iodomethane + CP all prevented severe RD. Broadcast soil fumigation with CP also was effective, but broadcast MB and 1,3-D were ineffective. In microplots filled with RD-conducive soil, CP was more potent than MB for prevention of RD on Nemaguard peach. There was no association between nematodes and RD in orchard or microplot trials. The RD apparently was mediated by a biological agent(s) other than nematodes and can be prevented by appropriate fumigation with CP or other MB alternatives.

Metamorphosis of Miracidia into Cercariae of Schistosoma mansoni in vitro

Parasitology ◽  
1969 ◽  
Vol 59 (2) ◽  
pp. 365-371 ◽  
Author(s):  
M. Muftic
Keyword(s):  
Schistosoma Mansoni ◽  
Snail Host ◽  
Control Measures ◽  
Intermediate Hosts ◽  
Host Parasite ◽  
And Control

At present our knowledge of the host-parasite relationships of the Schistosomatidae and their snail intermediate hosts is meagre. Because this knowledge is necessary in the search for effective therapeutic and control measures it would be useful to find an in vitro procedure facilitating continuous progenesis of schistosomes without the use of a snail host.

Continued Enhancement of SGT-600 Gas Turbine Design and Maintenance

2008 ◽  
Author(s):  
Vladimir Navrotsky ◽  
Mats Blomstedt ◽  
Niklas Lundin ◽  
Claes Uebel
Keyword(s):  
Life Cycle ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Life Cycle Cost ◽  
High Reliability ◽  
Medium Size ◽  
Power Turbine ◽  
History Of ◽  
And Control ◽  
Reliability And Availability

Current power generation and oil & gas markets are dynamic with continuously growing requirements on gas turbines for high reliability and availability and low emissions and life cycle cost. In order to meet these growing requirements on the gas turbines, the OEM should sustain continued product improvement and employment of innovative solutions and technologies in the area of design, operation and maintenance. This paper describes the successful development and operation experiences of SGT-600 Siemens’ medium size gas turbine and in particular the latest achievements in maintenance and life cycle improvements. High reliability and availability of SGT-600 gas turbine were enabled by further improvements and modifications of the combustor, compressor turbine blade 1 and vane 1, power turbine diffuser and control system. The developed modifications enable operators to utilize the opportunity: • to extend the life cycle of the engine beyond 120,000 EOH (Equivalent Operating Hours), up to 180,000 EOH, depending on the previous operation profile and history of the installation; • to extend the maintenance intervals from 20,000 EOH to 30,000 EOH and that to increase the availability of the engine by up to 1%; • to reduce the emission level to the latest SGT-600 standards.

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