The activity of aminoglycoside antibiotics against Trypanosoma brucei.

The trypanocidal activity of four aminoglycosides was determined against Trypanosoma brucei in vitro. The drug activity in descending order, was as follows; paromomycin kanamycin>gentamycin > neomycin. Paromomycin bad the highest activity and the concentration that inhibited 50% of trypanosome growth (IC50) was 11.

A competitive enzyme-linked immunosorbent assay for diminazene.

Diminazene aceturate has remained a very important therapeutic drug for trypanosomosis in cattle, sheep and goats since its introduction into the market in 1955. Despite its continued use, the methods available for its detection in body fluids are lengthy and inefficient for routine monitoring of drug levels in treated animals. A competitive enzyme linked immunosorbent assay (ELISA) has now been developed and optimized for the detection of diminazene in bovine serum.

The effects of drug-sensitive and drug-resistant Trypanosoma congolense infections on the pharmacokinetics of homidium in Boran cattle.

Two groups of five Boran (Bos indicus) cattle were infected with one of two populations of Trypanosoma congolense; one drug-sensitive (IL1180), and one drug-resistant (IL3330). The animals were then treated intramuscularly with homidium bromide at a dose rate of 1.0 mg kg(-1) bodyweight 7 days after trypanosomes were detected in the peripheral blood of all the five animals in each group.

Comparative sensitivity of dot-ELISA, PCR and dissection method for the detection of trypanosome infections in tsetse flies (Diptera: glossinidae).

A visually read dot-enzyme linked immunosorbent assay (dot-ELISA) developed for the detection of trypanosomes in tsetse flies (Glossina spp.) was evaluated in the laboratory and under field conditions. In the evaluation, the fly dissection method was used as a standard technique and compared to the polymerase chain reaction (PCR).

Development and evaluation of an enzyme-linked immunosorbent assay (ELISA) for the determination of the trypanocidal drug homidium in serum of treated cattle.

Two enzyme-linked immunosorbent assays (ELISA) for the determination of homidium in serum of treated cattle have been developed and evaluated. One is a direct competition (Assay 1) and the other an indirect competition assay (Assay 2). Both assays are highly sensitive with a limit of detection of 0.

Some pharmacokinetic parameters of the trypanocidal drug homidium bromide in Friesian and Boran steers using an enzyme-linked immunosorbent assay (ELISA).

Pharmacokinetic studies on the trypanocidal drug homidium bromide using a competitive enzyme immunoassay (detection limit 0.1 ng/mL) are reported for non-infected Friesian and Boran steers following treatment with homidium bromide at a dose of 1.0 mg/kg b.

Studies on host resistance to tick infestations among trypanotolerant Bos indicus cattle breeds in east Africa.

Recent epidemiological studies carried out in East Africa have indicated that some Bos indicus cattle breeds such as the Orma Boran and Maasai Zebu have a degree of trypanotolerance worth exploitation by their introduction into trypanosomosis endemic areas where other cattle breeds cannot survive. However, in most areas of East Africa, trypanosomosis, ticks, and tick-borne diseases occur together. It is therefore important to obtain information on the susceptibility of these breeds to tick infestation and tick-borne diseases.

Differences in cloning and sub-cloning success rates in four stocks of Trypanosoma evansi and variation in suramin resistance of the clones.

Four Trypanosoma evansi stocks with sensitivity to suramin in mice ranging from 0.05 to 160 mg kg-1 were cloned and sub-cloned and the sensitivity of the clones determined. The results suggest that it is easier to clone and sub-clone trypanosome stocks which are sensitive to suramin than those that are resistant to the action of the drug.

Comparison of isometamidium chloride and homidium bromide as prophylactic drugs for trypanosomiasis in cattle at Nguruman, Kenya.

The duration of prophylaxis provided by isometamidium chloride and homidium bromide, each at a dose rate of 1 mg kg-1 bodyweight, was compared in a 12-month field trial involving groups of 30 zebu cattle in south-west Kenya. The trial took place between February 1990 and February 1991 and included several months of high trypanosome challenge. Cattle in the prophylaxis groups were retreated on a group basis when 10% of the group had become infected since the previous group treatment.

Immunoassay of circulating trypanosomal antigens in sleeping sickness patients undergoing treatment.

Sera from 99 patients infected with Trypanosoma brucei rhodesiense and undergoing treatment, were analyzed for circulating trypanosomal antigens using a sandwich antigen-trapping enzyme-linked immunosorbent assay (ELISA). Trypanosomal antigens were detected in 83 (84%) of the patients. Post-treatment antigen profile in 67 patients showed five distinct patterns: in 48% of the patients antigen levels remained elevated throughout the time of hospitalisation and follow-up; in 31%, antigens dropped to the negative value by the second month; in 7.

Drug sensitivity screening in vitro of populations of Trypanosoma congolense originating from cattle and tsetse flies at Nguruman, Kenya.

An in vitro assay that utilises in vitro-derived metacyclic trypanosomes was used to determine the drug sensitivity of 7 populations of Trypanosoma congolense collected from cattle and tsetse flies at Nguruman; a trypanosomiasis-endemic area in southwest Kenya. The metacyclic trypanosomes used in the assay were obtained from cultures initiated directly from either the blood of cattle with low levels of parasitaemia or from guts of infected tsetse flies. Sensitivities to isometamidium chloride, diminazene aceturate and homidium salts were assessed at various drug concentrations (0.

An in vitro assay for drug sensitivity of Trypanosoma congolense using in vitro-derived metacyclic trypanosomes.

The sensitivity of seven populations of T. congolense to the salts of three trypanocides, diminazene, isometamidium and homidium, were determined in vitro using in vitro-derived metacyclic trypanosomes. The trypanosomes were incubated at 35 degrees C for 48 h with various drug concentrations (0.

The effect of cattle infection by Trypanosoma congolense on the attraction, and feeding success, of the tsetse fly Glossina pallidipes.

An incomplete ring of electric nets was placed around uninfected cattle and cattle infected with Trypanosoma congolense. The numbers of fed and unfed Glossina pallidipes caught on the nets were used to estimate the attractiveness of infected and uninfected cattle to tsetse, and the feeding success of tsetse on the cattle. There was no difference in the attractiveness of infected and uninfected cattle to G.

Preliminary observations on the efficacy of mel Cy (Cymelarsan) in domestic animals infected with stocks of Trypanosoma brucei brucei and T.b. evansi.

The trypanocidal activity of an arsenical compound (RM 110; mel Cy; Cymelarsan) was evaluated against Trypanosoma brucei brucei and T. brucei evansi in cultures, in goats and pigs. The trypanosome stocks used differed in their levels of susceptibility to cymerlarsan in an in vitro test, their IC50 values (drug concentration which inhibits growth by 50%) ranging from 4.

Failure of chemoprophylaxis against bovine trypanosomiasis on Galana Ranch in Kenya.

The duration of prophylaxis provided by 1 mg kg-1 bodyweight of homidium bromide was compared with that provided by 1 mg kg-1 bodyweight of isometamidium chloride in a 12 month field trial involving 90 Boran cattle exposed to trypanosome challenge on Galana Ranch in Kenya. Weekly trypanosome prevalences of over 30% were observed during 4 of the 12 months. During these periods of heavy challenge, parasites were detected 2-3 weeks after administration of both homidium bromide and isometamidium chloride.

Evaluation of DL-alpha-difluoromethylornithine against susceptible and drug-resistant Trypanosoma brucei brucei.

The antitrypanosomal activity of the ornithine decarboxylase inhibitor DL-alpha-difluoromethylornithine (DFMO, eflornithine) was tested in ten stocks and one clone of the hemoflagellate Trypanosoma brucei brucei in an in vitro system. They showed varying levels of susceptibility to DFMO, their IC50 (the concentration which inhibited growth by 50%) values ranging from 81-691 microM. Differences in DFMO susceptibility were also demonstrated in mice.

The relapse of Trypanosoma brucei brucei infections after chemotherapy in rabbits.

Infections of T. brucei in the rabbit were found to relapse after chemotherapy. The results indicated that 25 mg/kg diminazene aceturate given 3 days after infection resulted in a complete cure but if given 7 days after infection relapses frequently occurred.