Cyclic development and longevity of theileria parva in the tick rhipicephalus appendiculatus.
TL;DR: Stages of T. parva discovered in intestinal contents, gut epithelial cells, and the cells of the salivary glands are fully described, confirming the fact that the contained parasites die before the tick.
About: This article is published in Experimental Parasitology.The article was published on 1964-12-01. It has received 66 citations till now. The article focuses on the topics: Theileria parva & East Coast fever.
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TL;DR: Comparative biological and morphological studies show that the economically important piroplasms comprise three groups: (1) Babesia species sensu strictu ; (2) Bubesia equi , B. microti ; and (3) Theileria species.
Abstract: Publisher Summary The piroplasms are protozoa that are highly pathogenic to cattle, sheep, goats, and occasionally even to man. They comprise two genera—namely, Theileria and Babesia . The diseases they induce, known collectively as “theilerioses” and “babesioses,” cause fevers and lead to important economic losses in the tropics, subtropics, and southern Europe. This chapter highlights the differences between the life cycles of Babesia and Theileria species with respect to their morphology, studied by means of light and electron microscopy. The chapter describes the life cycle of piroplasms. They have a typical sporozoan life cycle comprising three phases: (1) Schizogony, an asexual reproduction phase in the vertebrate host. (2) Gumogony, the formation and fusion of gametes inside the intestinal cells of ixodid ticks. (3) Sporogony, an asexual reproduction in the salivary gland of the tick leading to the infectious, saliva-transmitted sporozoites. Comparative biological and morphological studies show that the economically important piroplasms comprise three groups: (1) Babesia species sensu strictu ; (2) Bubesia equi , B. microti ; and (3) Theileria species.
443 citations
TL;DR: This chapter discusses various aspects of the host response that affect tick feeding directly and studies the dependence on tick salivary glands of the disease-causing organisms Theileria and Babesia for their development and transmission.
Abstract: Publisher Summary Argasid ticks feed rapidly and pass through numerous moults to reach the engorged female stage On the other hand, the feeding of ixodid ticks is characterized by the capacity of each instar to ingest large volumes of host blood and so avoid the frequent host-finding associated with argasids These concentrate their meal with the coxal organ but ixodid ticks eliminate most excess water via the salivary glands, which have the capacity to secrete large volumes of water, particularly during the later stages of feeding This chapter discusses various aspects of the host response that affect tick feeding directly It also studies the dependence on tick salivary glands of the disease-causing organisms Theileria and Babesia for their development and transmission In many species, the salivary glands secrete cement that attaches the tick to the host for several days They synthesize and release a variety of enzymes and other chemicals, which may assist in the development of a feeding lesion and provide an ample flow of blood for engorgement In concentrating the blood meal, the salivary glands not only secrete excess water but also maintain the ionic balance of the hemolymph by selective secretion and retention of ions
107 citations
TL;DR: It was concluded that with this strain of ticks, reared and infected under the described conditions, the most suitable time for the recovery of the infective forms of T. parva would be the 4th day of feeding.
Abstract: Sections of salivary glands from the tick R. appendiculatus have been studied to obtain data on the incidence and development of Theileria parva during feeding. Adult ticks previously fed as nymphs on infected cattle were allowed to attach to rabbits after different periods following moulting and removed for dissection after different periods of attachment. The maximum number of parasites was present from the 3rd to the 5th days of attachment when 30·5–42 % of salivary glands were infected. A small number of undeveloped parasites was observed in the salivary glands of unfed ticks. The parasites were classified by their appearance into young, intermediate and mature forms and it was shown that the greatest numbers of mature forms were present on the 4th and 5th days of attachment. It was concluded that with this strain of ticks, reared and infected under the described conditions, the most suitable time for the recovery of the infective forms of T. parva would be the 4th day of feeding. Acknowledgements are due to the technical staff who contributed to this work, but especially to Mrs D. Backhurst who supervised the processing of the many sections, to Mr B. Wood who prepared the photomicrographs and to Mr K. P. Bailey who maintained the colony of infected R. appendiculatus . This work was carried out during the assignment of one of us (L.P.J.) by the Food and Agricultural Organization of the United Nations to the East African Veterinary Research Organization.
92 citations
TL;DR: The appearance of large nuclear-numbered macroschizonts and piroplasms was timedependent and not dose-dependent, suggesting that the switch to the maturation phase, from the exponential division phase or phases, occurs after a fixed number of divisions.
81 citations
01 Jan 1981
TL;DR: There have been few studies specifically on the epidemiology of theileriosis in East Africa as mentioned in this paper, however, the classical studies of Yeoman (1966a,b; 1967, 1967) and McCulloch et al (1968a, b) investigated the cause of the large epidemics of East Coast fever (E.C.F.) which occurred in Sukumal& Tanzania, concentrating on the populations of the tick vector Rhipicephalus appendiculatus.
Abstract: There have been few studies specifically on the epidemiology of theileriosis in East Africa. The classical studies of Yeoman (1966a,b; 1967) and McCulloch et al (1968a,b) investigated the cause of the large epidemics of East Coast fever (E.C.F.) which occurred in Sukumal& Tanzania, concentrating on the populations of the tick vector Rhipicephalus appendiculatus. Barnett (1968, 1977) and Barnett & Bailey (1955) reported studies in the field and laboratory which threw considerable light on the epidemiology of Theileria parva in endemic areas of Kenya. FAO (1975) undertook an enormous survey of the tick populations and T. parva antibodies from cattle in Kenya.
72 citations
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76 citations
TL;DR: Although the general arrangement of the musculature in the two families of the Ixodoidea is not fundamentally different, the comparative anatomy of the muscles offers some difficulty, owing to the great morphological differences which the two Families present.
Abstract: The muscular system is so highly developed in the Ixodoidea, that it is no matter of surprise that it has been the subject of more or less detailed treatment in most of the publications dealing with tick anatomy; but, with a single exception, the existing descriptions do not extend beyond a general classification of the various muscles, with the addition of brief remarks, in some instances, on the histological structure of the muscle fibres. In the majority of cases, also, the observations only apply to the Ixodid ticks, and although the general arrangement of the musculature in the two families of the Ixodoidea is not fundamentally different, the comparative anatomy of the muscles offers some difficulty, owing to the great morphological differences which the two families present.
64 citations
51 citations
01 Jan 1934
TL;DR: Die Verdauung ist bei Ixodes intracellular, der Darminhalt bleibt füissig oder es bilden rich Hämoglobinkrystalle, je nach dem artspezifischen Verhalten des gesogenen Blutes, und eigentlichen Darmzellen vermehren rich und wölben sich in das Darmlumen hinein.
Abstract: Die Verdauung ist bei Ixodes intracellular. Im Darm des nuchternen Weibchens gibt es drei Arten von Zellen, degenerierende Zellen, eigentliche Darmzellen and Driisenzellen. Nach dem Saugen findet sofort Hamolyse und Eindickung des aufgenommenen Blutes statt. Der Darminhalt bleibt fuissig oder es bilden rich Hamoglobinkrystalle, je nach dem artspezifischen Verhalten des gesogenen Blutes. Die eigentlichen Darmzellen vermehren rich und wolben sich in das Darmlumen hinein. Die Nahrung wird wenig verandert in flussigem Zustand in die Zellen aufgenommen, sammelt sich hier in Nahrungskugeln an und wird zu Exkreten abgebaut. Wenn alle Nahrung aus dem Darmlumen verschwunden ist, zerfallen die nur noch mit Exkreten erfullten Zellen und bleiben beim absterbenden Weibchen im Darmlumen liegen. Bei den Jugendstadien werden sic nach der Hautung durch den Enddarm entleert. Eine Anzahl von Zellen macht diesen ProzeB nicht mit, sondern liefert das Darmepithel des nachsten Entwicklungsstadiums oder degeneriert beim Weibchen. Uber die Natur der Exkrete konnte nichts ermittelt werden. Bei Ixodes plumbeus wird das Chromatin der Vogelblutkerne innerhalb der Darmzellen abgebaut. Die Wasserstoffionenkonzentration liegt wahrend der ganzen Verdauung zwischen 7,2 und 7,6. Solange noch Nahrung im Darmlumen ist, last sick das Wirtseiweis serologisch nachweisen. Bis auf Degenerationsstadien enthalten alle Darmzellen viel Fett. Symbionten werden bei Ixodes ricinus nicht beobachtet.
31 citations