Concentrations of isometamidium in the sera of cattle challenged with drug-resistant Trypanosoma congolense

cg.identifier.doihttps://doi.org/10.1016/s0001-706x(96)00602-xen_US
cg.issn0001-706Xen_US
cg.issue2-3en_US
cg.journalActa Tropicaen_US
cg.subject.ilriCATTLEen_US
cg.subject.ilriANIMAL HEALTHen_US
cg.subject.ilriLIVESTOCKen_US
cg.volume63en_US
dc.contributor.authorEisler, M.C.en_US
dc.contributor.authorGault, E.A.en_US
dc.contributor.authorMoloo, S.K.en_US
dc.contributor.authorHolmes, P.H.en_US
dc.contributor.authorPeregrine, A.S.en_US
dc.date.accessioned2013-06-11T09:25:40Zen_US
dc.date.available2013-06-11T09:25:40Zen_US
dc.identifier.urihttps://hdl.handle.net/10568/29975en_US
dc.titleConcentrations of isometamidium in the sera of cattle challenged with drug-resistant Trypanosoma congolenseen_US
dcterms.abstractThe relationship between serum concentrations of the prophylactic trypanocidal drug isometamidium chloride and protection against tsetse challenge with two populations of Trypanosoma congolense was investigated in Boran (Bos indicus) cattle, using an isometamidium-ELISA. Isometamidium chloride (Samorin) was administered to cattle at a dose rate of 1.0 mg/kg body weight by deep intramuscular injection. Thereafter, the animals were challenged at monthly intervals with either a drug-sensitive clone (T. congolense IL 1180) or a clone expressing a moderate level of resistance to isometamidium (T. congolense IL 3343). Untreated control cattle were used to confirm the infectivity of each challenge. Of ten drug-treated cattle that were challenged with T. congolense IL 3343, all were refractory to infection at the first challenge, 1 month after drug administration. However, all ten animals succumbed to infection at either the second (seven cattle) or third (three cattle) monthly challenges. By contrast, all five drug-treated cattle challenged with T. congolense IL 1180 resisted four monthly challenges. The mean isometamidium concentration at the time of the first, 1 month, challenge was 5.6 (+ or -) 2.8 ng/ml. At the time of the second monthly challenge the mean concentration was 2.0 (+ or -) 0.86 ng/ml; at this time, concentrations were not significantly different between those cattle refractory to challenge with T. congolense IL 3343 and those cattle that were not. Thus, differences in susceptibility to challenge at this time would appear to be due to differences in the drug sensitivity of the parasite challenge. Finally, the mean isometamidium concentration in uninfected cattle at the time of the fourth monthly challenge was 0.4 (+ or -) 0.18 ng/ml. These results indicate that when T. congolense infection occurs in cattle under isometamidium prophylaxis, the parasites may be considered at least moderately drug resistant if the concentration of isometamidium in serum is 2.0 ng/ml. At concentrations between 0.4 and 2.0 ng/ml a low level of drug resistance may be inferred. Below 0.4 ng/ml, however, no inference regarding drug resistance should be made.en_US
dcterms.accessRightsLimited Accessen_US
dcterms.bibliographicCitationActa Tropica;63(2,3): 89-100en_US
dcterms.extentp. 89-100en_US
dcterms.issued1997-02en_US
dcterms.languageenen_US
dcterms.licenseCopyrighted; all rights reserveden_US
dcterms.publisherElsevieren_US
dcterms.subjecttrypanosoma congolenseen_US
dcterms.subjectdrugsen_US
dcterms.subjectresistance to chemicalsen_US
dcterms.subjectelizaen_US
dcterms.subjectchemoprophylaxisen_US
dcterms.subjectcattleen_US
dcterms.subjectglossinidaeen_US
dcterms.subjectblood serumen_US
dcterms.typeJournal Articleen_US

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