Tropical biomedicine最新文献

Neurocysticercosis (NCC) is a parasitic infection of the nervous system and is responsible for considerable morbidity and mortality. Praziquantel (PZQ) is one of the antiparasitics mostly used in managing NCC, however, there have been only a few studies on the treatment outcome of this drug. The present study aimed to evaluate the efficacy and safety of PZQ in patients with NCC. Sixty patients with typical characteristics of NCC received three 10-day cycles of PZQ and the interruption between these cycles was 10 days. Additional treatment included antiinflammation (steroids), antiepileptics and analgesics. Clinical and imaging studies were done at baseline and six months after therapy to assess the efficacy of treatment. Laboratory evaluation was done before and after each cycle to investigate laboratory safety profiles. By six months after finishing therapy, all patients had clinical improvement and 75% of them were free of symptoms. The rates of complete, partial or no resolution of cysts on brain magnetic resonance imaging were 61.7%, 28.3% and 10% respectively. The efficacy of therapy was not associated with the number of cysts. There was no difference between the levels of aspartate aminotransferase, alanine aminotransferase, urea and creatinine before and after treatment. Conclusion: Praziquantel is effective and safe in the treatment of patients with neurocysticercosis.

Trypanosoma brucei parasites are flagellated kinetoplastid protozoan which is responsible for Human African Trypanosomiasis (HAT). Current chemotherapy drugs have a number of side effects and drug resistance has emerged as a major issue in current treatment. Active bisindole alkaloid compound ochrolifuanine was previously isolated from the leaves of Dyera costulata. In vitro antitrypanosomal activity of ochrolifuanine against Trypanosoma brucei brucei strain BS221 showed strong activity with an IC₅₀ value of 0.05 ± 0.01 µg/ml. We compared the effect of ochrolifuanine and reference compound staurosporine in T. b. brucei apoptosis. The apoptosis-inducing activity of ochrolifuanine was evaluated using TUNEL assay and cell cycle analysis. Trypanosoma brucei brucei was shown to undergo apoptotic cells death as demonstrated by the appearance of several conical hallmarks of apoptosis. Ochrolifuanine was found to induce apoptosis in parasites in a dose- and time-dependent manner. The cell cycle study revealed 0.025 and 0.05 µg/ml of ochrolifuanine arrested the growth of T. b. brucei at two different growth phases (G₀/G₁ and in S phases). While at concentration 0.10 µg/ml arrested at the G2/M phase. In conclusion, the results indicate that ochrolifuanine displayed an antitrypanosomal effect on T. b. brucei by inducing apoptosis cell death and causing the arrest of parasite cells at different growth phases. The results suggested that ochrolifuanine may be a promising lead compound for the development of new chemotherapies for African trypanosomiasis.

Newcastle Disease (ND) is a highly pathogenic disease of avian species which is caused by Newcastle Disease Virus (NDV). It is one of the major causes of mortality and morbidity to poultry industry in the third world countries. Currently, there is no treatment measures against ND; the only existing measure is vaccination, though it is incapable to offer 100% immunity. In Tanzania, the leaves of Synadenium glaucescens Pax. are traditionally used for treatment of various ailments including ND. Previously, its leaves extract has been scientifically confirmed to exhibit anti-NDV activity though bioactive compound(s) responsible for this activity is/are unknown. Therefore, this study was aimed to evaluate anti-NDV activity of 3β-Friedelanol (1) and 3α-friedelanol (2) isolated from its leaves extract. Isolation of these compounds was achieved by column chromatography method whereas, their chemical structures were determined by Nuclear Magnetic Resonance (NMR) data and by comparing with the available literature NMR data. Anti-NDV activity study was done in embryonated chicken eggs (ECEs). Treatment of NDV inoculated ECEs with 3β-Friedelanol (1) reduced the viral load to zero and maintained the survival of embryos, this was revealed by continuous organs formation and increase in embryo weights with no significant different (p > 0.05) from un-inoculated ECE. These effects suggest that, 3β-Friedelanol (1) possesses anti-NDV activity. Therefore, existence of 3β-Friedelanol (1) in the leaves of S. glaucescens may justify its earlier described anti-NDV activity and traditional use in the treatment of ND. Hence, its leaves extract may be considered for development of anti-NDV herbal formulation while 3β-Friedelanol could either serve as a drug or lead compound for synthesis of anti-NDV drugs.

Renocila richardsonae Williams & Bunkley-Williams, 1992 is recorded for the first time from Sarawak coastal waters. During a survey of marine fishes at depth of 200 metres in South China Sea, off the coast of Sarawak from 3° to 5°N and 110° to 111°E, five specimens of Renocila richardsonae were collected from Japanese goatfish, Upeneus japonicus (Houttuyn, 1782) (Mullidae) with average prevalence of 17% and mean intensity of one isopod per fish from examination of 64 fish. The isopod was observed to cause tissue damage on the site of attachment to the host.

Conventional culture method and biochemical tests remain as the 'gold standard' method for the identification of S. sonnei which are time-consuming. We have discovered previously the potential of three OMPs of S. sonnei (33.3 kDa, 43.8 kDa and 100.3 kDa) as biomarkers in the diagnostic test for shigellosis. Here, we evaluated the performance of the outer membrane proteins of S. sonnei for the development of an antibody-based immunoassay for the detection of S. sonnei infections. All threetarget proteins were specifically recognized when probed with S. sonnei sera. In addition, another two potential proteins of molecular weight 29.0 kDa and 88.2 kDa in size were also exclusively recognized by the IgA when probed with S. sonnei sera. The optimized ELISA demonstrated higher sensitivity and specificity which exceeded 86.0%. In conclusion, the identified target proteins showed great potential as diagnostic biomarkers for the detection of S. sonnei infections in patients.

At present, there are several synthetic medications for toxoplasmosis therapy; however, these agents cannot be permanently applied because of adverse side effects or therapeutic failures and drug resistance in parasites. The present experimental investigation was aimed to study the effects of royal jelly (RJ) obtained from Apis mellifera in comparison with atovaquone against Toxoplasma gondii infection in mice. After treatment of infected mice with RJ at the doses of 200, 400, and 600 mg/kg for 14 consecutive days, we evaluated the therapeutic activity of RJ by measuring the mean number and the mean size of T. gondii tissue cysts, oxidant-antioxidant enzymes, pro-inflammatory cytokines, the mRNA expression levels of bradyzoite surface antigen 1 (BAG1), as well as the toxic effect on liver and kidney function. Treatment of the infected mice with RJ significantly (p < 0.001) decreased the mean number and the mean diameter of T. gondii tissue cysts and downregulated BAG1 in a dose-dependent response. After treatment of infected mice with RJ, the level of oxidative stress markers was significantly diminished, but a significant increase (p < 0.05) in the level of antioxidant markers such as glutathione peroxidase (GPx) and superoxide dismutase (SOD) enzymes was observed. Treatment of the infected mice with RJ significantly enhanced the level of pro-inflammatory cytokines IFN-γ and IL-1β, whereas it caused no substantial change in the serum levels of liver and kidney enzymes. The findings of this in vivo study revealed the favorable therapeutic effect of RJ on latent T. gondii infection in mice. It was found that RJ considerably inhibited the infection by decreasing the number and size of tissue cysts, reducing oxidative stress, and boosting the level of pro-inflammatory cytokines, but had no significant toxic impact on the function of vital organs such as liver and kidney. However, additional surveys are required to confirm these findings and clarify the exact mechanisms and their efficiency in clinical subjects.

The Bornean sun bear, a subspecies of the endangered Malayan sun bear, resides only on Borneo Island and little is known about diseases or parasites that may impact their health. In 2019, blood and ticks were collected from 46 captive bears held at the Bornean Sun Bear Conservation Centre in Sabah, Malaysia during annual health examinations in response to previous blood smear analysis that revealed presumptive haemoparasites in more than half the resident bears. Polymerase chain reaction detected a unique Babesia sp. in one of the bears. Disease surveillance of mosquitoes trapped along the outer perimeter of the bears' outdoor enclosure did not reveal any malaria parasites. This research marks the first documented case in Bornean sun bears of both a Babesia sp. and the Ixodes tick Haemaphysalis nr koningsbergeri. More research on incriminating the vector and the effects of Babesia infection on the health of Bornean sun bears is needed. Due to the zoonotic nature of babesiosis, mitigative actions should be taken to protect any humans that work with or come into close contact with these captive bears or their enclosures.

Antimicrobial resistant Escherichia coli have become an ever increasing problem in human, and animal health and production. The imprudent use of antibiotics and poor hygienic practices especially in poultry industries have been contributing to the emergence and spread of E. coli species resistant to broad spectrum antibiotics including Colistin. This study was conducted to detect colistin - resistance and antibiotic sensitivity patterns in E. coli isolated from broiler chickens in Kelantan. A total of 320 cloacal swabs were collected from apparently healthy broiler chickens in different districts of Kelantan and were analysed using routine microbiological methods, Kirby-Bauer method for antimicrobial susceptibility test and PCR amplification of species-specific and colistin - resistance encoding genes. Out of the 320 samples, 91 isolates were confirmed as E. coli and 21/91 (23.08%) were positive for colistin - resistant encoding gene, mcr-1. Most of the isolates were resistant to tetracycline (95.24%), chloramphenicol (85.71%), and sulphamethoxazole/ trimethoprim (85.71%). However, the isolates were less resistant towards piperacillin/ tazobactam (4.76%) and meropenem (9.52%). The findings from this study reveal the emerging threats of colistin - resistant in local food animal production, particularly in poultry production industry. However, more comprehensive, and large-scale studies focusing on more resistance patterns using determination of minimum inhibitory concentration (MIC), virulence and resistance characteristics and molecular epidemiology of colistin - resistant E. coli are recommended for better understanding of the epidemiology and to implement the appropriate control and prevention strategies.

Among strategies for decreasing diseases, the use of larvicidal plant extracts against mosquito larvae gain an important place in vector control. The aim of the present study was to reveal the insecticidal effectiveness of an endemic medicinal plant on Mosquito-Borne Diseases. The chemical composition of the dried aerial part from Origanum floribundum Essential oil, obtained by hydrodistillation, was characterized by Fourier-transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometer (GC-MS) system. The potential larvicidal activity of this extract as bioinsecticide was assessed against Culex pipiens. Results showed many functional groups such as phenols and alcohols, besides, the chemical composition by GC-MS identified thymol (86.9%) and p-Cymene (5.1%) as major components. A significant larvicidal effect against the target mosquito species was noted, with values of LC₅₀ at 21.19 mg/l and LC₉₀ at 68.37 mg/l. The results obtained showed that the essential oil of Origanum floribundum with chemotype thymol possess a potent larvicidal activity and could be considered as an eco-friendly alternative for vector control.

Highly Pathogenic Avian Influenza (HPAI) is a highly contagious disease in poultry. The outbreaks can lead to flock mortality up to 100% in two to three days. In July 2018, high mortality in a commercial layer farm in Kauluan village, Sabah was reported. Samples were sent to Veterinary Research Institute Ipoh for diagnosis. Virus isolation and molecular detection is carried out simultaneously. The causative agent was then identified as AI H5N1 virus by real time reverse transcription-polymerase chain reaction (RT-PCR). The virus was then subjected for further nucleotide sequencing of full length hemagglutinin (HA) and neuraminidase (NA) gene. The PQRERRRKR/GLF motif at the HA cleavage site indicated that the isolate was of HPAI virus. Phylogenetic analysis of the HA gene showed that the isolate was belonged to the clade 2.3.2.1c virus. In the HA gene, besides the S133A substitution, the virus possesses conserved amino acid at most of the avian receptor binding sites including the glutamine (Q) and glycine (G) at position 222 and 224 respectively, indicating that the virus retains the avian-type receptor binding preference. As such, the zoonotic potential of the virus was relatively low. On the other hand, though the N154D and T156A substitution were detected in the same gene, the pandemic potential of this Sabah 2.3.2.1c virus is low in the absence of the Q222L, G224S, H103Y, N220K and T315I. A typical 20 amino acid deletion with loss of four corresponding glycosylation sites in the NA stalk region was visible. Though three NA resistance markers were detected, the virus was predicted to be sensitive to NA inhibitor. This is the first HPAI H5N1 outbreak in Sabah. The introduction of this virus into East Malaysia for the first time raised an alert alarm of the future epidemic potential. Strict farm biosecurity, continuous surveillance programme in poultry, wild birds, migratory birds; molecular epidemiology as well as risk assessment for the virus with pandemic potential are needed in dealing with emergence of new influenza virus in the country.