Diagnosis of trypanosomiasis in experimental mice and field-infected camels by detection of antibody to trypanosome tyrosine aminotransferase.

Sera from animals with acute and chronic Trypansoma evansi infections were examined directly for trypanosome tyrosine aminotransferase activity and indirectly for their ability to inhibit tyrosine aminotransferase activity. It was shown that sera from acutely infected mice and camels with high parasitemias contained significant levels of trypanosome tyrosine aminotransferase activity. In contrast, the sera from chronically infected mice and camels did not contain significant tyrosine aminotransferase activity, but they were able to neutralize the enzyme activity in trypanosome homogenates. The sera from camels with other pathological conditions did not neutralize this enzyme activity. It is suggested that the inhibitory factor in the chronic sera is antibody. The potential use of the direct enzyme assay and the indirect neutralization assay as diagnostic tools are discussed. Finally, the use of these assays to distinguish between early (acute) and late (chronic) infections are also suggested.

Increased excretion of aromatic amino acid catabolites in animals infected with Trypanosoma brucei evansi.

Aromatic amino acid catabolism by Trypanosoma brucei evansi was investigated in vivo using C3HeB/FeJ mice. The major catabolites detected by gas chromatography in the urines of infected animals were phenylpyruvic acid, 4-hydroxyphenylpyruvic acid, and indole-3-pyruvic acid. Identity of each compound was confirmed by gas chromatography-mass spectrometry. Concentrations of catabolites in urine of infected mice were correlated with parasitemia and returned to normal following suramin treatment. Other aromatic amino acid metabolites, including indole-3-acetic acid, indole-3-lactic acid, and 4-hydroxyphenyllactic acid, were detected in urine from infected animals by gas chromatography mass spectrometry, although quantities were too low to be quantified reproducibly. Both phenylpyruvic acid and 4-hydroxyphenylpyruvic acid were also detected in urine of dogs and donkeys experimentally infected in Egypt with a recent field isolate of T. b. evansi. Tryptophan metabolites could not be assayed in dog and urine samples because formalin, which degraded the indole acids, had to be added before the samples could be imported into the U.S. Finally, concentrations of urinary catabolites during infection were correlated with the tyrosine aminotransferase activity in infected mouse sera.

Diagnosis of chronic camel trypanosomosis by detection of the antibody of trypanosome tyrosine aminotransferase.

Sera from animals with acute and chronic T. evansi infections were examined directly for trypanosome tyrosine aminotransferase activity and indirectly for the ability of these area from mice and camels with high parasitaemias contained significant levels of trypanosome tyrosine aminotransferase activity. In contrast the chronic sera from both mice and camels did not contain significant tyrosine aminotransferase activity but the chronic sera were able to neutralize the enzyme activity in trypanosome homogenates. In addition to the sera from other pathological conditions did not neutralize the enzyme activity. It is suggested that the inhibitory factor in the chronic sera is antibody. The potential use of the direct enzyme assay, and the indirect neutralization assay as diagnostic tools are discussed. Finally, the use of these assays to distinguish between early (acute) and late (chronic) infections are also suggested.

Catabolism of tryptophan by Trypanosoma evansi.

Trypanosoma brucei gambiense, which causes human African trypanosomiasis, catabolizes the aromatic amino acid tryptophan via an initial aminotransferase catalyzed reaction to form several indole end products, which have been suggested to contribute to the pathogenesis of trypanosomiasis. To determine if this same pathway exists in T. evansi, the closely related trypanosome pathogen of domestic animals, tryptophan catabolism was examined in vitro and in vivo. As is the case with human African trypanosomes, T. evansi catabolized tryptophan to form indole-3-pyruvic acid and smaller amounts of indole-3-acetic acid and indole-3-lactic acid. Large concentrations of indole-3-pyruvic acid are excreted in urine of trypanosome-infected mice. However, indole-3-ethanol could not be detected in incubates of T. evansi or T. b. gambiense, even though the latter species had previously been reported to form this neutral metabolite. A new, previously unreported tryptophan metabolite was isolated and partially characterized from incubates of T. evansi and T. b. gambiense. Although the functional significance of tryptophan catabolism to trypanosomatids remains obscure, the pathway is quantitatively significant in all species examined thus far.

Evaluation of A live trivalent vaccine for infectious bovine rhinotracheitis virus, para-influenza type-3 virus and Pasteurella multocida in calves.

A live trivalent vaccine for Infectious Bovine Rhinotracheitis virus (IBR), Para-influenza type-3 virus (PI3) and Pasteurella multocida type B vaccine was prepared. The preparation contained 10(7) TCID50 of IBR, 10(7) TCID50 of PI3 & 10(9) CFU of P. multocida type B per 3 ml. Ten calves (5-7 days old) were vaccinated intranasally while five unvaccinated calves of the same age were used as control. Vaccinated calves were examined daily for disease manifestation. Serum and nasal secretion specimens were collected prevaccination and at 7, 15, 21, 30, 45 and 60 days following vaccination. The results indicated that, intranasal vaccination with the live trivalent vaccine stimulates the development of satisfactory level of circulating and mucosal antibodies. It is concluded that the prepared vaccine may be useful for controlling Bovine respiratory disease in calves.