Dose dependent responses of cattle to Theileria parva stabilate

Dolan, T.T.; Young, A. S.; Losos, G.J.; McMilian, I.; Minder, Ch. E.; Soulsby, K.

doi:10.1016/0020-7519(84)90017-1

Cited by 51 publications

(23 citation statements)

References 27 publications

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“…In cattle, after inoculation with as little as one red blood cell infected with Babesia bovis , another apicomplexan parasite, there was an increase in the prepatent period (as we also observed) but the high morbidity and mortality of animals was not altered in comparison to those infected with higher inocula [18]. These findings are in contrast to those for infections with the haemoparasite Theileria parva , where infection of cattle with a low inoculum resulted in decreased severity of disease and lower mortality [19]. Interestingly, in studies of Eimeria infection of chickens and rats, it was especially noticeable that with the greatest infecting dose, the number of oocysts produced per oocyst inoculated was smaller [20].…”

Section: Discussionsupporting

confidence: 62%

Cryptosporidium parvum Infection in SCID Mice Infected with Only One Oocyst: qPCR Assessment of Parasite Replication in Tissues and Development of Digestive Cancer

et al. 2012

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Dexamethasone (Dex) treated Severe Combined Immunodeficiency (SCID) mice were previously described as developing digestive adenocarcinoma after massive infection with Cryptosporidium parvum as soon as 45 days post-infection (P.I.). We aimed to determine the minimum number of oocysts capable of inducing infection and thereby gastrointestinal tumors in this model. Mice were challenged with calibrated oocyst suspensions containing intended doses of: 1, 10, 100 or 105 oocysts of C. parvum Iowa strain. All administered doses were infective for animals but increasing the oocyst challenge lead to an increase in mice infectivity (P = 0.01). Oocyst shedding was detected at 7 days P.I. after inoculation with more than 10 oocysts, and after 15 days in mice challenged with one oocyst. In groups challenged with lower inocula, parasite growth phase was significantly higher (P = 0.005) compared to mice inoculated with higher doses. After 45 days P.I. all groups of mice had a mean of oocyst shedding superior to 10,000 oocyst/g of feces. The most impressive observation of this study was the demonstration that C. parvum-induced digestive adenocarcinoma could be caused by infection with low doses of Cryptosporidium, even with only one oocyst: in mice inoculated with low doses, neoplastic lesions were detected as early as 45 days P.I. both in the stomach and ileo-caecal region, and these lesions could evolve in an invasive adenocarcinoma. These findings show a great amplification effect of parasites in mouse tissues after challenge with low doses as confirmed by quantitative PCR. The ability of C. parvum to infect mice with one oocyst and to develop digestive adenocarcinoma suggests that other mammalian species including humans could be also susceptible to this process, especially when they are severely immunocompromised.

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Section: Discussionsupporting

confidence: 62%

Cryptosporidium parvum Infection in SCID Mice Infected with Only One Oocyst: qPCR Assessment of Parasite Replication in Tissues and Development of Digestive Cancer

et al. 2012

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“…If all the immunized cattle had a similar neutralizing antibody effect on sporozoites, then variation in disease reactions could be explained by differences in their infectivity thresholds (33). However, the antibody titers in the immunized cattle were not similar nor did they correlate with disease reactions, suggesting that the quality of antibody may also be important.…”

Section: Discussionmentioning

confidence: 99%

A recombinant sporozoite surface antigen of Theileria parva induces protection in cattle.

Musoke¹,

Morzaria²,

Nkonge³

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

107

106

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At present immunization against Theileria parva is by infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. This method has major limitations in that live organisms are used and the immunity engendered is parasite stock specific. In an attempt to develop an alternative immunization procedure, the gene encoding p67, a major surface antigen of sporozoites, has been expressed by using the plasmid expression vector pMG1. The gene, which has been characterized previously, encodes 709 amino acid residues, contains a single intron of 29 base pairs, and is only transcribed during sporogony. The recombinant p67 sequences were fused to the first 85 amino acid residues derived from a nonstructural gene (NS1) of influenza virus A. Immunization with a partially purified recombinant antigen emulsified in 3% saponin induced sporozoite neutralizing antibodies in cattle and provided protection in six of nine animals on homologous challenge with T. parva sporozoites. This recombinant antigen is therefore a candidate for development of a vaccine against T. parva.

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“…The onset and severity of ECF disease clinical signs is related to the number of parasites inoculated into the host. Cattle receiving higher numbers of sporozoites generally develop clinical signs earlier with higher parasitemia than those receiving lower doses [12, 57]. As the exact number of sporozoites each animal received through tick feeding is unknown, it is difficult to know if animal BF003 and BF030 did not develop disease clinical signs due to their higher p67 antibody titres or a chance lower tick infection rate.…”

Section: Discussionmentioning

confidence: 99%

Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission

et al. 2016

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Background: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tickborne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model. Methods: Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model.

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Dose dependent responses of cattle to Theileria parva stabilate

Cited by 51 publications

References 27 publications

Cryptosporidium parvum Infection in SCID Mice Infected with Only One Oocyst: qPCR Assessment of Parasite Replication in Tissues and Development of Digestive Cancer

Cryptosporidium parvum Infection in SCID Mice Infected with Only One Oocyst: qPCR Assessment of Parasite Replication in Tissues and Development of Digestive Cancer

A recombinant sporozoite surface antigen of Theileria parva induces protection in cattle.

Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission

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