Experimental Work with the Tsetse-fly, Glossina palpalis, in Uganda

1936 ◽  
Vol 27 (4) ◽  
pp. 611-632 ◽  
Author(s):  
Kenneth Mellanby
Keyword(s):  
Life Cycle ◽  
East Africa ◽  
Experimental Work ◽  
Laboratory Experiments ◽  
Climatic Conditions ◽  
Tsetse Fly ◽  
London School ◽  
East African ◽  
Laboratory Assistant ◽  
Glossina Palpalis

This is an account of laboratory experiments made with the tsetse Glossina palpalis. The results deal mainly with the effects of climatic conditions, temperature and humidity in particular, on the metabolism and life-cycle. Some work was also done on the activity and behaviour of the fly, but this is very incomplete, though it shows the importance of the problem and the need for further study.The work was done during a visit of just over a year to East Africa, in 1935-36, as Wandsworth Scholar of the London School of Hygiene and Tropical Medicine. I spent most of the time at the Human Trypanosomiasis Institute, Entebbe, Uganda, and also visited tsetse areas in Kenya and Tanganyika. I am grateful to all those who helped to make my visit profitable. Among others, to the Directors of Medical Services of the East African territories, in particular the Hon. W. H. Kauntze of Uganda, and many members of their departments. To Mr. C. B. Symes, Medical Entomologist, Kenya, and to Mr. W. H. Potts, of the Department of Tsetse Research, Tanganyika. I am especially grateful to Dr. H. Lyndhurst Duke, Director of the Human Trypanosomiasis Institute, for many kindnesses. Considerable assistance was received from Mrs. Helen Mellanby, who was working on allied problems at Entebbe. And mention must be made of the intelligent and conscientious help of my laboratory assistant, Omw. Bonaventure Semalwadde.

Aircraft Applications of Insecticides in East Africa. I.—Preliminary Experiments in Areas supporting Populations of the Tsetse Fly (Glossina palpalis (R.-D.))

1953 ◽  
Vol 44 (3) ◽  
pp. 589-600 ◽  
Author(s):  
K. S. Hocking ◽  
D. Yeo
Keyword(s):  
East Africa ◽  
Meteorological Conditions ◽  
Tsetse Fly ◽  
Treated Area ◽  
Dense Forest ◽  
Glossina Palpalis

Preliminary experiments are described of applications from aircraft of coarse sprays and coarse aerosols. The experiments were carried out over dense forest areas containing the tsetse fly G. palpalis.At dosages of 0·2 lb. per acre of the p,p'isomer of DDT, or 0·032 lb. per acre of the γ isomer of BHC, both the sprays and the aerosols were relatively ineffective, and significant kills were obtained only with the aerosols.The sprays were ineffective not only because they did not penetrate the canopy, but also because the nominal dosage was in any case too small to produce lethal deposits upon vegetation.Much of the aerosol was filtered out by the upper layers of the canopy. The meteorological conditions in the area were also unsuitable for the application of aerosols, and much of the insecticide did not reach the canopy, but was blown away from the treated area.It is concluded that aircraft applications of insecticide against G. palpalis are wasteful of insecticide, and would be very costly if substantial reductions in fly population were to be obtained. If insecticides are to be of value in such areas, ground methods of applying them would be almost certainly more effective, and less costly.

The life cycle of Paramphistomum microbothrium Fischoeder, 1901 (Trematoda, Paramphistomidae)

Parasitology ◽  
1954 ◽  
Vol 44 (3-4) ◽  
pp. 285-299 ◽  
Author(s):  
J. A. Dinnik ◽  
N. N. Dinnik
Keyword(s):  
Life Cycle ◽  
Life Span ◽  
Intermediate Host ◽  
East Africa ◽  
Laboratory Experiments ◽  
First Generation ◽  
Infected Snail ◽  
Successive Generations ◽  
Whole Life Cycle ◽  
Further Development

The whole life cycle of Paramphistomum microbothrium Fischoeder, 1901, found in cattle of Kenya, East Africa, has been established experimentally.In laboratory conditions, the eggs hatched miracidia on the 14th to 16th day, if they were kept in water at a temperature of 26–28° C.In a snail, Bulinus alluaudi (Dautzenberg), kept at the temperature of 18–20° C., the miracidium developed into a sporocyst, the elongated body of which, containing young rediae, reached a length of 3·6 mm. in about 2 weeks.The first rediae which emerged from a sporocyst were observed on the 14th day, and on the 20th day the first generation rediae began to produce second-generation rediae. From the 28th day onward the first-generation parent rediae ceased to produce daughter rediae and began to develop cercariae only. This period of production of cercariae by the redia lasted about 30 days, and when the life of the first-generation rediae drew to its close, the old rediae developed a few daughter rediae again.Cercariae began to emerge from the first-generation rediae 30 days after exposure of the snail to miracidia. The cercariae left the parent redia in a very immature state and further development occurred in the liver of the snail. The emergence of cercariae from the infected snail began on the 43rd day after exposure to miracidia. Shortly after emerging from the snail, the cercariae attached themselves to vegetation and encysted.Development of rediae of the second, third, fourth and apparently more successive generations followed an identical course to that outlined for the rediae of the first generation. As a result the successive generations of rediae maintain the infection going in an intermediate host and the infected snails were continually shedding cercariae as long as they lived. In the laboratory experiments the life span of some of the infected snails exceeded a year.In cattle infected experimentally P. microbothrium reached maturity and began passing out the eggs about a 100 days after the encysted cercariae were fed to the animals.

Studies onTrypanosoma grayi. III. Life-Cycle in the Tsetse-fly and in the Crocodile

Parasitology ◽  
1931 ◽  
Vol 23 (4) ◽  
pp. 449-484 ◽  
Author(s):  
Cecil A. Hoare
Keyword(s):  
Life Cycle ◽  
Peripheral Circulation ◽  
Tsetse Fly ◽  
Peritrophic Membrane ◽  
Invertebrate Host ◽  
Hind Gut ◽  
Time Required ◽  
Very High ◽  
Glossina Palpalis

An account is given of the life cycle and morphology ofT. grayiin the crocodile (Crocodilus niloticus) and in the tsetse-fly (Glossina palpalis). The immunological relations of this trypanosome to its hosts and its affinities to other species are also dealt with.T. grayibelongs to the group of trypanosomes developing in the posteriorstation of the invertebrate host and transmitted by the contaminative method (“lewisigroup”).T. grayioccurs in very small numbers in the crocodile and is concentrated chiefly in the peripheral circulation of the skin (about 200 parasites per 1 c.c. of blood). It is one of the largest trypanosomes, the blood forms measuring up to 91μWhen fed on an infected crocodile the tsetse-fiy takes up not more than about six trypanosomes. These commence their development in the mid-gut, giving rise to crithidial and trypanosome forms, and later extend to the hind-gut where their evolution is completed and the infective metacyclic trypanosomes are produced. These, when voided with the faeces, serve to infect the crocodileper os.Since the incubation period ofT. grayiin the crocodile is about four days, this is the time required for the small metacyclic trypanosomes to develop into the large blood forms.The distribution ofT. grayiin the gut of the fly in the course of its development is determined by the presence of the peritrophic membrane and involves three successive waves of migration in opposite directions: (1) From the intraperitrophic space backwards, into the colon, thence (2) forwards into the extraperitrophic space up to and including the mid-gut; and finally (3) they again migrate backwards, to the hind-gut. (Diagrams of the life cycle and distribution ofT. grayiinGlossinaare given in Text-figs. 2 and 3.)Evidence is produced to show that the so-called “cysts” ofT. grayidescribed by previour authors are really artifacts.Apparently the majority of crocodiles in Victoria Nyanza harbourT. grayi. The trypanosome has no harmful efleet upon the crocodile and it was proved that the infection can persist for more than two years.The crocodile appears to possess anaturalpartial or tolerance immunity againstT. grayi, which does not protect it from invasion by the parasite, but maintains its numbers at a constantly low level.The infection rate in the experimental tsetse-ffies is very high (average 61 per cent.) in the early days of infection, but later f ails to an average of 17·3 per cent. The majority of the flies, originally fully susceptible to infection, appear toacquirean immunity after the fifth day.The average degree of infection in “wild” flies is 11·2 per cent. This compares closely with that in the experimental flies. Hence it is inferred that the majority of these flies had fed in nature on infected crocodiles.T. grayiis closely allied to trypanosomes of the “lewisigroup” and to some of the trypanosomes of land reptiles and amphibia. On the strength of the clifterence existing between these two groups of trypanosomes, some modification in the accepted classification of these species is introduced.A name,T. theodorisp.n., is proposed for the goat trypanosome described by Theodor (1928).

The War of Legs

Transfers ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 102-120
Author(s):  
Michael Pesek
Keyword(s):  
World War I ◽  
Medical Care ◽  
East Africa ◽  
Transport Infrastructure ◽  
World War ◽  
East African ◽  
Colonial State ◽  
History Of ◽  
Main Factors ◽  
Belgian Congo

This article describes the little-known history of military labor and transport during the East African campaign of World War I. Based on sources from German, Belgian, and British archives and publications, it considers the issue of military transport and supply in the thick of war. Traditional histories of World War I tend to be those of battles, but what follows is a history of roads and footpaths. More than a million Africans served as porters for the troops. Many paid with their lives. The organization of military labor was a huge task for the colonial and military bureaucracies for which they were hardly prepared. However, the need to organize military transport eventually initiated a process of modernization of the colonial state in the Belgian Congo and British East Africa. This process was not without backlash or failure. The Germans lost their well-developed military transport infrastructure during the Allied offensive of 1916. The British and Belgians went to war with the question of transport unresolved. They were unable to recruit enough Africans for military labor, a situation made worse by failures in the supplies by porters of food and medical care. One of the main factors that contributed to the success of German forces was the Allies' failure in the “war of legs.”

scholarly journals Metabolic reprogramming during the Trypanosoma brucei life cycle

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 683 ◽  
Author(s):  
Terry K. Smith ◽  
Frédéric Bringaud ◽  
Derek P. Nolan ◽  
Luisa M. Figueiredo
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Model Organism ◽  
Protozoan Parasite ◽  
Tsetse Fly ◽  
Metabolic Reprogramming ◽  
Mammalian Host ◽  
Insect Vector ◽  
Environmental Signals ◽  
Cellular Metabolic Activity

Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.

scholarly journals Integrated economic and environmental building classification and optimal seismic vulnerability/energy efficiency retrofitting

2021 ◽  
Author(s):  
Martina Caruso ◽  
Rui Pinho ◽  
Federica Bianchi ◽  
Francesco Cavalieri ◽  
Maria Teresa Lemmo
Keyword(s):  
Energy Efficiency ◽  
Life Cycle ◽  
Seismic Hazard ◽  
Environmental Impacts ◽  
Classification System ◽  
Seismic Vulnerability ◽  
Performance Metrics ◽  
Climatic Conditions ◽  
Economic Losses ◽  
Operational Energy

AbstractA life cycle framework for a new integrated classification system for buildings and the identification of renovation strategies that lead to an optimal balance between reduction of seismic vulnerability and increase of energy efficiency, considering both economic losses and environmental impacts, is discussed through a parametric application to an exemplificative case-study building. Such framework accounts for the economic and environmental contributions of initial construction, operational energy consumption, earthquake-induced damage repair activities, retrofitting interventions, and demolition. One-off and annual monetary expenses and environmental impacts through the building life cycle are suggested as meaningful performance metrics to develop an integrated classification system for buildings and to identify the optimal renovation strategy leading to a combined reduction of economic and environmental impacts, depending on the climatic conditions and the seismic hazard at the site of interest. The illustrative application of the framework to an existing school building is then carried out, investigating alternative retrofitting solutions, including either sole structural retrofitting options or sole energy refurbishments, as well as integrated strategies that target both objectives, with a view to demonstrate its practicality and to explore its ensuing results. The influence of seismic hazard and climatic conditions is quantitatively investigated, by assuming the building to be located into different geographic locations.

scholarly journals Crustal variability along the rifted/sheared East African margin: a review

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Maren Vormann ◽  
Wilfried Jokat
Keyword(s):  
East Africa ◽  
Shear Zone ◽  
Structural Changes ◽  
The South ◽  
East African ◽  
The North ◽  
Rifted Margins ◽  
Continental Block ◽  
Seismic Lines ◽  
Southeastern Madagascar

AbstractThe East African margin between the Somali Basin in the north and the Natal Basin in the south formed as a result of the Jurassic/Cretaceous dispersal of Gondwana. While the initial movements between East and West Gondwana left (oblique) rifted margins behind, the subsequent southward drift of East Gondwana from 157 Ma onwards created a major shear zone, the Davie Fracture Zone (DFZ), along East Africa. To document the structural variability of the DFZ, several deep seismic lines were acquired off northern Mozambique. The profiles clearly indicate the structural changes along the shear zone from an elevated continental block in the south (14°–20°S) to non-elevated basement covered by up to 6-km-thick sediments in the north (9°–13°S). Here, we compile the geological/geophysical knowledge of five profiles along East Africa and interpret them in the context of one of the latest kinematic reconstructions. A pre-rift position of the detached continental sliver of the Davie Ridge between Tanzania/Kenya and southeastern Madagascar fits to this kinematic reconstruction without general changes of the rotation poles.

Aircraft Applications of Insecticides in East Africa. VIII.—An Experiment against the Tsetse Fly, Glossina swynnertoni Aust., in an isolated Area of Thronbush and Thicket

1954 ◽  
Vol 45 (3) ◽  
pp. 613-622 ◽  
Author(s):  
K. S. Hocking ◽  
G. F. Burnett ◽  
R. C. Sell
Keyword(s):  
East Africa ◽  
Apparent Density ◽  
Significant Degree ◽  
Tsetse Fly ◽  
Central Province ◽  
The North ◽  
Insecticidal Treatment ◽  
Bad Weather ◽  
Glossina Swynnertoni ◽  
Better Than

An isolated area of 2,200 acres of thicket and thronbush in the Central Province, Tanganyika, was treated from the air with a DDT-in-oil aerosol in an attempt to eliminate the tsetse fly, Glossina swynnertoni Aust. Eight applications of 0·25 lb. technical DDT per acre were planned to be done at fortnightly intervals.Delays due to unseasonal bad weather reduced this to seven at a slightly higher rate and over a longer-period.G. swynnertoni was reduced from an apparent density of about 7 to zero at the end of the second application. No flies were caught after the fifth application for a period of six months.It is not possible to say whether the few caught since then have been brought in or are the offspring of survivors of the insecticidal treatment.This experiment was more successful than that on the Galapo Block in the same ares, to a highly significant degree, and this is attributed to the vulnerability of the smaller population present. It was doubtfully better than the first treatment of the North Block, also in this area, because the increase in population in the latter block may have been assisted by immigration.

scholarly journals Epidemic malaria and warmer temperatures in recent decades in an East African highland

2010 ◽  
Vol 278 (1712) ◽  
pp. 1661-1669 ◽  
Author(s):  
David Alonso ◽  
Menno J. Bouma ◽  
Mercedes Pascual
Keyword(s):  
Climate Change ◽  
East Africa ◽  
Nonlinear Response ◽  
Climate Change Impacts ◽  
Human Model ◽  
Recent Past ◽  
East African ◽  
Highly Nonlinear ◽  
The Impact

Climate change impacts on malaria are typically assessed with scenarios for the long-term future. Here we focus instead on the recent past (1970–2003) to address whether warmer temperatures have already increased the incidence of malaria in a highland region of East Africa. Our analyses rely on a new coupled mosquito–human model of malaria, which we use to compare projected disease levels with and without the observed temperature trend. Predicted malaria cases exhibit a highly nonlinear response to warming, with a significant increase from the 1970s to the 1990s, although typical epidemic sizes are below those observed. These findings suggest that climate change has already played an important role in the exacerbation of malaria in this region. As the observed changes in malaria are even larger than those predicted by our model, other factors previously suggested to explain all of the increase in malaria may be enhancing the impact of climate change.

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