Systematic surveys of the wild macaques of South Asia by blood culture resulted in the discovery that trypanosomiasis is enzootic in the simians of Indonesia, Malaysia, India, and Thailand. The isolates obtained differ in morphology, metabolism, and ability to multiply in arthropods. Following this discovery, interest focused on possible transmissions of these trypanosomiases. Laboratory-reared and wild-caught insects were studied to determine which are satisfactory intermediate hosts and potential natural vectors. Successful results were obtained with insectary-reared reduviids and Indonesian isolates. In Rhodnius prolixus and Triatoma rubrofasciata the Indonesian trypanosomes multiply for periods which can exceed 40 days. The flagellate infections are in the digestive tract, whereas trypanosomes have never been seen in the salivary glands or in the hemolymph. The feces of trypanosome-carrying reduviids are infective, suggesting a stercoreal method of infection of mammals, and infection was produced in experiments in which feeding by the insects was not possible. The relevance of these findings to natural transmission in Indonesia is not known. Experiments with insects and all other trypanosomal isolates have been negative. The natural transmission mechanism(s) of the simian trypanosomiases in South Asia remains an unsolved problem.
An investigation into the epidemiology of Trypansoma evansi infection in crossbred dairy cattle was conducted for a period of 12 months on a dairy cattle farm in Penninsular Malaysia. The prevalence of parasitaemia was highest in lactating animals (13.4%), followed by those in the dry herd (8.8%), late pregnant animals (8.1%), early pregnant animals (4.7%), calves (0.3%) and heifers (0.2%). The prevalence of antigenaemia was highest in the lactating animals (54.7%), followed by that in dry animals (53.7%), heifers (51.1%), late pregnant animals (47.7%), early pregnant animals (46.5%) and calves (24.2%).
Dichloromethane extracts of the root bark and stem bark of Kigelia pinnata collected from Zimbabwe exhibited antitrypanosomal activity against Trypanosoma brucei brucei in vitro. Activity-guided fractionation led to the isolation of four naphthoquinones from both the root and stem bark of the plant. The compounds were identified as 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-quinone (1), isopinnatal (2), kigelinol (3), and isokigelinol (4). Subsequently, the compounds were assessed for antitrypanosomal activity against T. brucei brucei and T. brucei rhodesiense bloodstream form trypomastigotes in vitro. Compound 1 with a furanonaphthoquinone structure was found to possess pronounced activity against both parasites with IC50 values of 0.12 and 0.045 microM, respectively, although it was less active than the standard drug pentamidine. Compounds 2, 3, and 4 also exhibited activity against the parasites, although to a lesser extent. The activities of the compounds were further assessed by comparison with the cytotoxic activities obtained against KB cell lines.
Three new 5,1'-coupled naphthylisoquinoline alkaloids, ancistrobenomine A (1), 6-O-demethylancistrobenomine A (2), and 5'-O-demethylancistrocline (3), have been isolated from the stem bark of a botanically as yet undescribed highland liana Ancistrocladus sp., proposed to be named "A. benomensis" according to the region in Peninsular Malaysia where it has been discovered on the mountain of Gunung Benom. Two of the compounds possess an unprecedented structure with a novel hydroxymethylene group at C-3 of the fully dehydrogenated isoquinoline moiety. The structural elucidation was achieved by chemical, spectroscopic, and chiroptical methods. As typical of the so-called Ancistrocladaceae type, all of the compounds isolated bear an oxygen at C-6. Biological activities of these alkaloids against different protozoic pathogens are described.
During a period of four consecutive years, trypanosomosis surveys were conducted in a tsetse-infested and tsetse-free area of the Amhara Region of north-west Ethiopia. In each study area randomly selected communal cattle were sampled and their blood was investigated using parasitological diagnostic methods. At the same time the population of biting flies was sampled. The monthly average prevalence of trypanosome infections in cattle did not differ significantly between study areas. In both study areas, the prevalence of trypanosome infections was highest during the long rainy season. Trypanosome infections were mainly due to Trypanosoma vivax and they significantly reduced the average packed cell volume and the body condition of the animals. The monthly prevalence of infection was correlated with the density of biting flies, such as Tabanidae and Stomoxys spp., in the preceding month suggesting an important role of mechanical transmission in the epidemiology of trypanosomosis in both areas.
Three new fully dehydrogenated naphthylisoquinoline alkaloids, the 7,1'-coupled ent-dioncophylleine A (3a), the likewise 7,1'-coupled 5'-O-demethyl-ent-dioncophylleine A (4), and the 7,8'-linked dioncophylleine D (5), have been isolated from the leaves of the recently described Malaysian highland liana Ancistrocladusbenomensis. All of them lack an oxygen function at C-6; this so-called Dioncophyllaceae-type structural subclass had previously been found only in naphthylisoquinoline alkaloids from West and Central African plants. Moreover, compounds 3a and 4 are the first fully dehydrogenated, i.e., only axially chiral, naphthylisoquinoline alkaloids of this type that are optically active; compound 5, by contrast, is fully racemic, due to its configurationally unstable biaryl axis. The structural elucidation was achieved by spectroscopic and chiroptical methods. Biological activities of these alkaloids against different protozoan parasites are described.
A study was conducted to determine the incidence of trypanosome infections in cattle in tsetse-free and tsetse-infested zones of the Amhara Region of northwest Ethiopia. A total of six sentinel herds were established and the cattle observed during a period of 8 consecutive months. The prevalence of seropositive cattle was high in both the tsetse-free and tsetse-infested zones. The average monthly incidence of trypanosome infection, determined using molecular diagnostic tools, was 20.9% and 25.7% in the tsetse-free and the tsetse-infested zones, respectively. In the tsetse-free, Trypanosoma vivax was responsible for 90.9% of the cattle trypanosome infections. In the tsetse-infested zone, Trypanosoma congolense and T. vivax contributed almost equally to the trypanosome infections in cattle. Trypanosome infection, regardless of species, resulted in anaemia as evidenced by a significant decrease in the packed cell volume of the infected animal. The outcome of this longitudinal study suggests that control of trypanosomiasis in the Amhara Region cannot be achieved by tsetse control alone. Supplemental measures to include drug therapy and biting fly control are discussed.
A map on a group is not necessarily an automorphism on the group. In this paper we study the necessary and sufficient conditions for a map on a non-split metacyclic p-group to be an automorphism, where we only consider p as an odd prime number. The metacyclic group can be defined by a presentation and it will be beneficial to have a direct relation between the parameters in the presentation and an automorphism of the group. We consider the action of an automorphism on the generators of the group mentioned. Since any element of a metacyclic group will be mapped to an element of the group by an automorphism, we can conveniently represent the automorphism in a matrix notation. We then use the relations and the regularity of the non-split metacyclic p-group to find conditions on each entry of the matrix in terms of the parameters in its presentation so that such a matrix does indeed represent an automorphism.
A comparative seroprevalence study on bovine trypanosomiasis and anaplasmosis was conducted. Sera of adult cattle and buffaloes of different breeds from farms from five different states in Malaysia were collected and tested for the presence of Trypanosoma evansi antibodies by CATT and Anaplasma marginale antibodies by c-ELISA. Of the 116 samples, 14.7% tested positive for bovine trypanosomiasis and 77.6% for bovine anaplasmosis.
Essential oil from Cymbopogon nardus was evaluated for activity against Trypanosoma brucei brucei BS221 (IC50 = 0.31 ± 0.03 μg/mL) and cytotoxic effect on normal kidney (Vero) cells (IC50 = >100 μg/mL). The crude essential oil was subjected to various chromatography techniques afforded active sub fractions with antitrypanosomal activity; F4 (IC50 = 0.61 ± 0.06 μg/mL), F6 (IC50= 0.73 ± 0.33 μg/mL), F7 (IC50 = 1.15 ± 0 μg/mL) and F8 (IC50 = 1.11 ± 0.01 μg/mL). These active fractions did not exhibit any toxic effects against Vero cell lines and the chemical profiles investigation indicated presence of α-and γ-eudesmol, elemol, α-cadinol and eugenol by GC/MS analysis.
A cross-sectional study was designed to assess the seroprevalence and risk factors associated with Trypanosoma evansi infection among horses, using a total of 527 blood samples obtained from eight states in Peninsular Malaysia. A structured questionnaire was used to collect data on risk factors associated with T. evansi seroprevalence. The overall seroprevalence detected by card agglutination test for T. evansi (CATT/T. evansi) was 13.90% (73/527, CI: 11.2-17.1%). Female and exogenous horses showed a higher risk in association with the disease seroprevalence compared to other groups. The majority of the horse owners were not familiar with surra (85.30%). However, most of them were very cautious with the health of their animals. In conclusion, this study showed that T. evansi occurred in low frequency among horses in Peninsular Malaysia, and the good management system adopted by horse owners was probably responsible for the low T. evansi occurrence.
Apart from occasional reports of clinical disease affecting horses, there is no information about Trypanosoma evansi in horses in Peninsula Malaysia. Thus, a cross-sectional study was conducted in eight states in Peninsula Malaysia to determine the active presence of T. evansi in horses. A total of 527 blood samples were obtained and examined by haematocrit centrifugation technique (HCT), Giemsa-stained thin blood smear (GSS), morphometric measurements, polymerase chain reaction (PCR) and cloning of PCR products. The results showed an overall parasitological prevalence of 0.57% (3/527, CI: 1.6-0.19%) with both HCT and GSS. Morphometric study revealed the mean total length of the trypanosomes including the free flagellum was 27.94 ± 2.63 μm. PCR successfully amplified a trypanosome specific 257 bp in 1.14% of samples (6/527, CI: 2.4-0.52%) and was confirmed by nucleotide sequences. The mean packed cell volume (PCV) for the positive cases detected by HCT was lower (23% ± 7.00) compared to the positive cases detected by PCR alone in the state of Terengganu (35% ± 4.73). In conclusion, this study showed T. evansi infection occurred in low frequency in horses in Peninsula Malaysia, and anaemia coincided with parasitaemic animals. PCR is considered as a sensitive diagnostic tool when parasitaemia is undetectable. The slight lengthier mean of parasite and anaemia may indicate a virulent strain of T. evansi circulating throughout the country. Thus, it's highly recommended to shed light on host-parasite relationship for better epidemiological understanding.
Oligopeptidase B (OPB) is a member of the prolyl oligopeptidase (POP) family of serine proteases. OPB in trypanosomes is an important virulence factor and potential pharmaceutical target. Characteristic structural features of POP family members include lack of a propeptide and presence of a β-propeller domain (PD), although the role of the β-PD has yet to be fully understood. In this work, residues Glu(172), Glu(490), Glu(524) and Arg(689) in Trypanosoma brucei OPB (Tb OPB), which are predicted to form inter-domain salt bridges, were substituted for Gln and Ala, respectively. These mutants were evaluated in terms of catalytic properties and stability. A negative effect on kcat/Km was obtained following mutation of Glu(172) or Arg(689). In contrast, the E490Q mutant exhibited markedly decreased thermal stability, although this mutation had less effect on catalytic properties compared to the E172Q and R689A mutants. Trypsin digestion showed that the boundary regions between the β-PD and catalytic domains (CDs) of the E490Q mutant are unfolded with heat treatment. These results indicated that Glu(490) in the CD plays a role in stabilization of Tb OPB, whereas Glu(172) in the β-PD is critical for the catalytic activity of Tb OPB.