noun
definition
Any of a group of protozoan parasites which are transmitted by biting insects and infect the blood of humans and other vertebrates.
Examples of trypanosomes in a Sentence
Trypanosomes were next seen in human blood 1 Trypanophis, although lacking (so far as is known) a haemal habitat, is included here, since it is undoubtedly closely related to Trypanoplasma.
Trypanosomes are harboured by members of all the chief classes of vertebrates with the exception of cyclostomes.
In considering the occurrence of Trypanosomes in mammals, careful distinction must be drawn between natural or true hosts, which are tolerant of the parasites, and casual ones, which are unaccustomed and unadapted to them.
Very many of the common domestic mammals can be successfully infected (either thus accidentally or else on purpose) with different " pathogenic " Trypanosomes, to which they succumb more or less readily, but they cannot be regarded as the natural hosts of those Trypanosomes.
Similarly with regard to the many other pathogenic Trypanosomes now known, there is undoubtedly, in each case, some indigenous wild animal tolerant of that particular form, which serves as a " latent source of supply " to strange mammals.
Until lately it remained quite uncertain, however, whether the invertebrate merely conveys the Trypanosomes or whether 1 Trypanosoma equiperdum, the cause of dourine in horses and asses, is apparently only conveyed by the act of coitus.
We cannot write quite so confidently with regard to the relation of the various pathogenic Trypanosomes to Tsetseflies (Glossinae).
By this means it has been ascertained with practical certainty that, among the family of Tsetseflies (Glossinae) for instance, at least four species are the natural carriers of different Trypanosomes.
Schaudinn had fully described the relations of certain avian Trypanosomes to their invertebrate host, Culex pipiens (females).
The Trypanosomes ultimately overrun practically all parts of the body, sometimes not even the ova escaping.
The life of the parasites while in the insect is characterized by an alternation of active periods, during which multiplication goes on, with resting-periods, when the Trypanosomes become attached to the epithelial cells of the host.
The Trypanosomes, in the active phase, are of course always free in the blood plasma (interglobular).
Ingestion and dissolution of the Trypanosomes by phagocytes has frequently been observed; and it is probable also that the haematopoietic organs secrete some substance which exerts a harmful action on the parasites, and causes them to undergo involution and assume weird-looking " amoeboid " and " plasmodial " forms.
Agglomeration consists in the grouping or union together of several Trypanosomes around a common centre; this leads to the formation of rosette-like clusters, or even of large masses composed of several rosettes.
If a favourable change in the surrounding medium sets in, the Trypanosomes are able to undergo the reverse process, namely disagglomeration; the parasites liberate themselves and the rosette is dissolved.
Trypanosomes vary greatly with regard to size; even in one and the same species this variation is often noticeable, especially under.
In many cases, at any rate, this indicates a difference in sexuality; and it is particularly necessary to bear this factor in mind when considering the avian Trypanosomes, where, perhaps, the extremes of form are to be met with.
In all other Trypanosomes there is only one flagellum, which is invariably attached to the body in the same manner as the posterior one of biflagellate forms. This flagellum, however, is most probably not to be considered homologous in all cases.
The genus Trypanosoma, in which are included at present the great majority of Trypanosomes, is rather to be regarded as derived from a Heteromastigine ancestor, such as Trypanoplasma, by the loss of the anterior flagellum.
A differentiation of the peripheral cytoplasm in the form of an ectoplasmic layer has been described in one or two instances, and it seems probable that in most Trypanosomes there is such a layer, although only poorly developed, as a rule, around the body generally.
The small Trypanosomes resulting from either of these modes of division differ from typical adults by their stumpy, pyriform shape, the position of the kinetonucleus near the flagellar end of the body, and the absence, during the first part of their youth, of an undulating-membrane.
Comprehensive researches (1905, seq.) have made it evident that Trypanosomes have a much more varied and complex development and life-history than was previously supposed.
Keysselitz (16), from fishes; also several other piscine Trypanosomes have their development phases in leeches worked on by Brumpt (5a).
In other words, he considers that these two Haemosporidian forms are really only phases in the life-history of particular Trypanosomes.
The female Trypanosomes, on the other hand, grow to a large size, laying up a store of reserve nutriment.
So far as regards the remarkable connexion between Trypanosomes and Haemosporidia indicated by Schaudinn, this has met with a great deal of criticism on the part of Novy and McNeal among others, and it must be admitted that up to 1909 no definite corroboration can be said to have been brought forward.
As remarked in the section on morphology, the Trypanosomes as a whole are preferably regarded as including tion.
Nothing definite is yet known with regard to the transmission of the parasites by an alternate invertebrate host, although there is presumptive evidence in favour of this supposition.2 A word or two must be said in conclusion with reference to the supposed connexion of the Spirochaetae with the n Trypanosomes.
On the other hand, evidence has lately been brought forward to show that certain parasites which greatly resemble a Spirochaele are really related to the Trypanosomes.
Once inoculated by an infected fly, the trypanosomes proliferate and gradually invade all the organs of the host.
Researchers, therefore, have strong reasons to suspect that a number of species transmit trypanosomes mechanically.
Despite their long-term use and limited number, little is understood on how these drugs kill trypanosomes.
So we've been investigating the early events in fly infection using fluorescent trypanosomes.
Tabanus occidentalis was understandably the biggest culprit, tho six other species had trypanosomes in their bloodmeals.
African trypanosomes have a fundamental mechanism by which they evade the immune response.
With relatively few wild animals now in the region, local cattle have become the main reservoir for human trypanosomes responsible for sleeping sickness.
They then excrete infective trypanosomes in their feces which enter the blood of a subsequent victim through the bite wound.
In this way we hope to find out where hybrid trypanosomes first appear during the complex migratory route of T. brucei in the fly.
I. Screening of activity to bacteria, fungi and American trypanosomes of 13 native plants.
Trypanosomes were first met with in cases of disease by Griffith Evans, who in 1880 found them in the blood of horses suffering from surra in India.
Schaudinn (50), who investigated certain avian Trypanosomes, considered the latter view to be correct, and believed that the carrier - in this instance a gnat - is indeed the definitive host, i.e.
In addition, there are two or three obervations to hand which shew that piscine, amphibian and mammalian Trypanosomes may also become attached.
The approach could also potentially help eliminate local foci for trypanosomes causing sleeping sickness in humans.
So we 've been investigating the early events in fly infection using fluorescent trypanosomes.