Objective:To investigate the effect of diminazene aceturale(DA) alone or in combination with either levamisole and/or Vitamin C in albino rats experimentally infected with Trypanosoma brucei brucei.Methods:Thirty adul...Objective:To investigate the effect of diminazene aceturale(DA) alone or in combination with either levamisole and/or Vitamin C in albino rats experimentally infected with Trypanosoma brucei brucei.Methods:Thirty adult male albino rats,randomly assigned into 6 groups(A—F) of 5rats each were used.They were either infected with 1×10~a trypanosomes intraperitoneally(groups A-E) or uninfected(group F).The different groups were treated respectively as follows:group A-with 3.5 mg/kg DA;group B-3.5 mg/kg DA and 7.5 mg/kg levamisole;group C-3.S mg/kg DA and 100 mg/kg vitamin C;and group D-3.S mg/kg DA and 7.S mg/kg levamisole and 100 mg/kg vitamin C.Croup E was left untreated.Parameters assessed include:rectal temperature,body weight changes,packed cell volume(PCV),Haemoglobin concentration(Hb),total leucocyte count(TLC) differential leucocyte count(DLC),parasitaemia,clinical signs and survivability.Results:Average pre-patent period of 5 days was recorded.Parasites in the blood were cleared in all treated groups(A-D) within 48 hours post treatment(PT).Untreated rats in group E died between25 and 32 days post infection(PI).Relapse was not recorded in all the treated groups(A-D).The initial reduction in PCV,Hb,TLC and increases in rectal temperature following infection were reversed by the treatments.The rats that received drug combinations(groups B,C and D)showed faster and higher recovery rates than the uninfected control and group A.Conclusions:Levamisole and/or Vitamin C combination with DA were more effective in the treatment of rats infected with Trypanosoma brucei brucei.展开更多
Objective:To investigate thein vitroandin vivoeffect of whole plant extracts ofPeristrophe bicalyculataonTrypanosoma brucei brucei-infected rats.Methods:The experiment wasdivided into two phases:In the first phase,the...Objective:To investigate thein vitroandin vivoeffect of whole plant extracts ofPeristrophe bicalyculataonTrypanosoma brucei brucei-infected rats.Methods:The experiment wasdivided into two phases:In the first phase,the anti-trypanosomal activity of the hot water,cold water,methanol and butanol extracts of the whole plant were determined by incubatingwithTrypanosoma brucei brucei.The cold water extract was partially-purified and the anti-trypanosomal activity of the fractions determined.In the second phase,Trypanosoma brucei brucei-infected rats were treated with fraction 2c for nine days.Packed cell volume(PCV),highdensity lipoprotein(HDL),low density lipoprotein(LDL),total cholesterol(TC),triacylglycerol(TAG),aspartate aminotransferase,alanine aminotransferases(ALT),alkaline phosphatase(ALP),total and direct bilirubin levels were determined at the end of the experiment.Results:Cold water extract immobilized 90%of the parasites after 60 min of incubation,and fraction 2ccompletely immobilized the parasites after 35 min.It significantly increased PCV inTrypanosoma brucei brucei-infected rats.Decreased TC,TAG,HDL and LDL levels of infected rats increasedsignificantly when rats were treated with the fraction,while elevated levels of total bilirubinand ALT also decreased.The difference in urea,direct bilirubin and ALP was not significantwhen infected rats were compared to rats in other groups.Conclusions:The ability of the plantto ameliorate the infection-induced biochemical changes calls for detailed investigation of thepotentials of the plant for antitrypanosomiasis drug delivery.展开更多
Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei(T.brucei) on dam and offspring.Methods:Sixty female Albino rats(Rattus norvegicus) weighing between 130-170 g were us...Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei(T.brucei) on dam and offspring.Methods:Sixty female Albino rats(Rattus norvegicus) weighing between 130-170 g were used as animal model.The animals were divided as follows: 25 infected between 1-5 days post partum;10 infected unbred as positive controls;and 25 uninfected as negative controls.The following parameters were evaluated:packed cell volume (PCV),level of parasitaemia,survival time,litter size and litter weight at birth and on days 7, 14 and 21 post delivery,using conventional methods.Possible trans-mammary transmission of infection to litter through milk was also assessed.Results:The results showed a comparatively (P【0.05) higher mean PCV value for the uninfected negative control on the 8 day post infection compared with the infected groups which corresponded with the increasing level of parasitaemia in the two infected groups.Mean litter size and litter weights were higher(P【0.05) in the uninfected controls on the 21<sup>st</sup> day.Survival time in the infected groups were similar.No evidence of trans-mammary transfer of infection was recorded.Conclusion:T.brucei infection during immediate post partum period is detrimental to the dam and impairs growth of the offspring.展开更多
Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wi...Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wide range of therapies.The utilization of animals and plants products has presented therapeutic potential for identifying novel anti-trypanosomal drugs.This study evaluated toad venom for anti-trypanosomal potency in-vivo in Swiss mice.Toads were collected from July to August 2019.The acute oral toxicity and biochemical characterization of the toad venom were determined.The experimental mice were administered various doses(130 mg/kg,173 mg/kg and 217 mg/kg)of the toad venom crude extract and 0.75 mg/mL of Diamizan Plus standard drug for the treatment of trypanosomiasis,once daily for 3 days.The in-vivo anti-trypanosomal activity was evaluated by a curative test,after infecting the mice with Trypanosoma brucei brucei.The pre-patent period was 72 hours before treatment commenced.The overall results showed that trypanosomal load was highest in the control group while the group treated with Diamizan drug had the least trypanosomal load.As such,the mean trypanosomal load in relation to treatments showed a very high significant difference(P<0.05).Also,the mean trypanosomal load in Swiss mice in relation to the highest dosage of toad venom versus Diamizan drug showed a very high significant difference(P<0.05).The mean change in relation to the haematological parameters across treatments groups varied significantly(P<0.05)with the exception of Hb which showed no significant difference(P>0.05)across treatment groups.The over 50%reduction in the trypanosomal load in the 130 mg/kg group in comparison with the control group brings to bare the anti-trypanosomal potency of the toad venom.The anti-trypanosomal activity demonstrated by the toad venom has provided basis for development of new therapeutic agents from different toad species.The study recommends further studies(both in-vivo and in-vitro)followed by the characterization of the active compounds present in the toad venom responsible for the anti-tyrpanosomal activity observed alongside the management and conservation of these species.展开更多
Apoptosis in single-cell organisms like Trypanosoma or Leishmania was characterized in several studies in the last few years [1]-[4]. Cell death in these caspase lacking protozoa is still poorly understood and a concl...Apoptosis in single-cell organisms like Trypanosoma or Leishmania was characterized in several studies in the last few years [1]-[4]. Cell death in these caspase lacking protozoa is still poorly understood and a conclusive apoptotic pathway has not been identified so far. In the work presented here, we studied the effects of prostaglandin D2 and staurosporine induced cell death in blood-forms of Trypanosoma brucei in a time dependent manner and focused on the role of a nuclease similar to endonuclease G of higher eukaryotes. We found that these parasites undergo apoptotic cell death as demonstrated by the appearance of several canonical hallmarks of apoptosis in higher eukaryotes, but that different stimuli induce remarkable differences in the way these cells die. We compared the effects of prostaglandin D2 and staurosporine in trypanosomes with and without endonuclease G overexpression by flow cytometric and electron microscopic methods with the result that endonuclease G overexpression led to a significant modification of intracellular organelles and accelerated apoptotic cell death in prostaglandin D2 or staurosporine treated cells. Our results demonstrate that different stimuli induce apoptosis even in these ancient organisms in different caspase-independent ways. Whereas central processes of apoptosis like ROS formation, loss of mitochondrial membrane potential, endonuclease G release, phosphatidylserine exposure and DNA fragmentation appeared in the same chronology during treatment with either one of both drugs, other effects like cell cycle arrest or change of cell shape occurred only in the case of prostaglandin D2 or staurosporine treatment. We conclude from these results that trypanosomes react to stimuli of apoptosis with the concerted action of cellular responses but cannot control the final outcome if additional stress, as in the case of staurosporine, is superimposed.展开更多
Human African trypanosomiasis (HAT) affects up to half a million people every year in sub-Saharan Africa. Interruption of transmission of the disease by early diagnosis and treatment is core to the control and eventua...Human African trypanosomiasis (HAT) affects up to half a million people every year in sub-Saharan Africa. Interruption of transmission of the disease by early diagnosis and treatment is core to the control and eventual elimination of HAT. The routine diagnostic method for HAT is light microscopy of blood samples. The present study sought to evaluate the potential of TbgI2 and TbgI17 tandem repeat antigens as candidates for the diagnosis of Trypanosoma brucei rhodesiense. The expressed proteins were purified and the antigenic reactivity evaluation was done using multiplex assay using sera obtained from HAT patients. Receiver operating characteristic analysis showed that recombinant antigen, TbgI2 had high sensitivity for sera from patients infected with T. b. rhodesiense with the area under the curve being 0.577 and a sensitivity of 0.641 and specificity 0.650. The results suggest that TbgI2 is a potential biomarker for T. b. rhodesiense HAT serodiagnostic tests.展开更多
Background:Human African trypanosomiasis(HAT)is one of the most complex parasitic diseases known to humankind.It usually occurs in endemic areas in Africa,but is occasionally detected in returning travelers and migran...Background:Human African trypanosomiasis(HAT)is one of the most complex parasitic diseases known to humankind.It usually occurs in endemic areas in Africa,but is occasionally detected in returning travelers and migrants in non-endemic countries.Case presentation:In August 2017,a case of HAT was diagnosed in China in a traveler returning from the Masai Mara area in Kenya and the Serengeti area in Tanzania.The traveler visited Africa from 23 July to 5 August,2017.Upon return to China,she developed a fever(on 8 August),and Trypanosoma brucei rhodesiense infection was confirmed by laboratory tests(on 14 August)including observation of parasites in blood films and by polymerase chain reaction.She was treated with pentamidine followed by suramin,and recovered 1 month later.Conclusions:This is the first imported rhodesiense HAT case reported in China.This case alerts clinical and public health workers to be aware of HAT in travelers,and expatriates and migrants who have visited at-risk areas in Africa.展开更多
Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats.Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanos...Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats.Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats.Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei.Results:Parasitaemia was recorded in Group B by(3.86±0.34)d and the peak of parasitaemia was observed at Day 5 post infection.Classical signs observed included squint eyes,raised whiskers,lethargy,no weight loss,pyrexia,isolation from the other rats,and starry hair coat.Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.展开更多
Objective:To establish the modulatory effects of coenzyme Q_(10)on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalop...Objective:To establish the modulatory effects of coenzyme Q_(10)on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy(PTRE).Methods:Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q_(10)after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense(T.b.rhodesiense).The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE.Parasitaemia development,packed cell volume,haematological and pathological changes were determined.Results:A histological study in the brain tissue of T.b.rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups.A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q_(10)was administered.Furthermore,the mean tissue weight of spleen to body ratio in coenzyme Q_(10)supplemented group was significantly(P<0.05)different compared to un-supplemented groups,and clearly indicated that coenzyme Q_(10)prevented full blown splenomegaly pathogenesis by T.b.rhodesiense.A significant(P<0.05)increase in hemoglobin levels and red blood cells was observed in coenzyme Q_(10)mice compared to those infected and un-supplemented with coenzyme Q_(10).Conclusions:The capacity of coenzyme Q_(10)to alter the pathogenesis of T.b.rhodesiense infection in mice and following treatment with melarsoprol,may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.展开更多
Objective:To determine the effect of Trypanosoma brucei(T.brucei)on blood sugar level of infected rats.Methods:The experiment was done with 42 albino rats grouped into 3 groups of 14 members each.Group A was uninfecte...Objective:To determine the effect of Trypanosoma brucei(T.brucei)on blood sugar level of infected rats.Methods:The experiment was done with 42 albino rats grouped into 3 groups of 14 members each.Group A was uninfected(control group),Group B was infected with T.brucei and treated with diminazene aceturate,and Group C was infected with T.brucei and treated with imidocarb dipropionate.Blood samples were collected from the media canthus of the experimental rats on Days 0,1,2,3,4,5,6,7,8,9,10 for the assessment of change in blood sugar levels.The blood sugar levels were determined with a glucometer(Accu-chek active serial No.GN:10023338).Results:By 4 to 5 days post infection,there was a significant increase(P<0.05)in the blood sugar of Group B and Group C.By Day 6 post infection(Day 2 post treatment),no significant difference(P>0.05)was observed in the groups when compared with the control group till Day 12 of the experiment.Conclusions:T.brucei caused a significant increase in blood sugar of infected rats.展开更多
Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10&...Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10<sup>5</sup> Trypanosoma in normal saline.Five days when a high level of parasiteamia was established treatment commenced until ten days.The mice were treated with 10,20 and 40 mg/kg bt.of the extract and 5 and 10 mg/kg bt.of the fraction(F<sub>2</sub>),respectively for 5 days.Diminazene acelurate at the dose of 3.5 mg/kg bt.for two days was used as the reference drug.The level of parasitaemia and packed cell volume(PCV) of the animals estimated. Results:At doses of 10,20 and 40 mg/kg the crude extract showed a sharp reduction in the level of parasitaemia in mice compared with the untreated group.The mice treated with F,at doses of 5 and 10 mg/kg showed a sharp reduction in the level of parasitamia to zero in day 9,and a gradual recovery from the 12th day of treatment.This effect is comparable to that of the mice treated with 7 mg/kg of standard drug diminazene aceturate.The PCV of the treated showed a gradual decrease with time,but not as much as the untreated group.Phytochemical screening revealed the presence of glycosides,alkaloids,carbohydrates,tannins and proteins in the Abrus precatorius powder while F<sub>2</sub> was rich in alkaloids.Conclusions:This study shows that both the extract and the fractions of Abrus precatorius seeds exhibited a promising trypanocidal property.Alkaloids may be responsible for the observed activity.展开更多
Objective:To investigated the prevalence of human African trypanosomiasis(HAT),a neglected tropical disease caused by Trypanosoma brucei gambiens in an endemic focus of Nigeria,as it relates to age,sex and occupationa...Objective:To investigated the prevalence of human African trypanosomiasis(HAT),a neglected tropical disease caused by Trypanosoma brucei gambiens in an endemic focus of Nigeria,as it relates to age,sex and occupational differences.Methods:A total of 474 human subjects were screened using card agglutination test for trypanosomiasis kit.Positive samples were further investigated for parasite positivity in blood/serum and cerebrospinal fluid(CSF).Results:Of the 474 screened,44(9.3%) were seropositive with seroprevalence of 22(9.6%) in Urhouka,14(9.5%) in Umeghe and 8(7.9%) for Ugonu.The number of seropositives,observed for weakly,moderately and strongly positives for the three communities were 4,7 and 11 in Urhouka,4,5 and 5 in Umeghe and 3,2 and 3 in Ugonu respectively.Among the 16 volunteers with detected parasite in their blood,4 of them were weakly positive,5 of them were moderately positive and 7 of them strongly positive.4 volunteers from Urhouka community were found parasites in their CSF and they were all strongly positive.The difference between the seroprevalence of males and females was not statistically significant(OR=1.14,95%CI=0.37-3.4,P】0.05).The prevalence difference between age group 21-30 years old and the youngest and oldest age groups was statistically significant(OR=3.5,95%CI= 1.08-12.57,P【0.05) but not significant for other age categories (P】0.05),It was observed that farmers had significantly higher prevalence of HAT infection as well as greater risk of Trypanosoma brucei gambiense infection than inhabitants with other occupations (OR=3.25,95%CI=0.99-11.79,P【0.05).Conclusions:Human activities such as farming and visits to the river have been identified as major risk factors to HAT.Also the breakdown of HAT control program has been advanced for the rise in HAT in Abraka,an endemic focus in Nigeria.展开更多
Human African trypanosomiasis (HAT), or sleeping sickness, caused by Trypanosoma brucei gambiense, is associated with diverse clinical outcomes. Host’s genetic factors involved in immunity are potential factors that ...Human African trypanosomiasis (HAT), or sleeping sickness, caused by Trypanosoma brucei gambiense, is associated with diverse clinical outcomes. Host’s genetic factors involved in immunity are potential factors that can regulate infection. Genetic polymorphisms within HLA-G could influence the level of HLA-G expression and therefore play a critical role in infection outcomes. The goal of our study was to investigate the association of 14 bp Indel HLA-G polymorphism with the susceptibility/resistance to HAT. DNA samples were collected from 119 cases, 221 controls and 43 seropositive individuals living in Ivorian HAT foci. The 14 bp Indel polymorphism was determined by PCR. Homozygous individuals for 14 bp insertion had a lower risk of progressing to active HAT (p = 0.012, OR = 0.27, 95% CI: 0.09 - 0.8). Moreover, the frequency of 14 bp insertion homozygous genotype was higher in the seropositive group (11%) than in the HAT cases group (3%) (p = 0.043, OR = 0.27, 95% CI: 0.07 - 0.99), which suggested a protective effect of 14 bp insertion homozygous genotype. Genetic polymorphisms in HLA-G may be associated with a variable risk to develop HAT. The 14 bp insertion appears to favour the occurrence of long-lasting T. b. gambiense latent infections.展开更多
文摘Objective:To investigate the effect of diminazene aceturale(DA) alone or in combination with either levamisole and/or Vitamin C in albino rats experimentally infected with Trypanosoma brucei brucei.Methods:Thirty adult male albino rats,randomly assigned into 6 groups(A—F) of 5rats each were used.They were either infected with 1×10~a trypanosomes intraperitoneally(groups A-E) or uninfected(group F).The different groups were treated respectively as follows:group A-with 3.5 mg/kg DA;group B-3.5 mg/kg DA and 7.5 mg/kg levamisole;group C-3.S mg/kg DA and 100 mg/kg vitamin C;and group D-3.S mg/kg DA and 7.S mg/kg levamisole and 100 mg/kg vitamin C.Croup E was left untreated.Parameters assessed include:rectal temperature,body weight changes,packed cell volume(PCV),Haemoglobin concentration(Hb),total leucocyte count(TLC) differential leucocyte count(DLC),parasitaemia,clinical signs and survivability.Results:Average pre-patent period of 5 days was recorded.Parasites in the blood were cleared in all treated groups(A-D) within 48 hours post treatment(PT).Untreated rats in group E died between25 and 32 days post infection(PI).Relapse was not recorded in all the treated groups(A-D).The initial reduction in PCV,Hb,TLC and increases in rectal temperature following infection were reversed by the treatments.The rats that received drug combinations(groups B,C and D)showed faster and higher recovery rates than the uninfected control and group A.Conclusions:Levamisole and/or Vitamin C combination with DA were more effective in the treatment of rats infected with Trypanosoma brucei brucei.
基金Supported by Education Trust Fund of Nigeria with the grant number ETF/DESS/AS&D/UNIV/ABU/ZARIA/V2
文摘Objective:To investigate thein vitroandin vivoeffect of whole plant extracts ofPeristrophe bicalyculataonTrypanosoma brucei brucei-infected rats.Methods:The experiment wasdivided into two phases:In the first phase,the anti-trypanosomal activity of the hot water,cold water,methanol and butanol extracts of the whole plant were determined by incubatingwithTrypanosoma brucei brucei.The cold water extract was partially-purified and the anti-trypanosomal activity of the fractions determined.In the second phase,Trypanosoma brucei brucei-infected rats were treated with fraction 2c for nine days.Packed cell volume(PCV),highdensity lipoprotein(HDL),low density lipoprotein(LDL),total cholesterol(TC),triacylglycerol(TAG),aspartate aminotransferase,alanine aminotransferases(ALT),alkaline phosphatase(ALP),total and direct bilirubin levels were determined at the end of the experiment.Results:Cold water extract immobilized 90%of the parasites after 60 min of incubation,and fraction 2ccompletely immobilized the parasites after 35 min.It significantly increased PCV inTrypanosoma brucei brucei-infected rats.Decreased TC,TAG,HDL and LDL levels of infected rats increasedsignificantly when rats were treated with the fraction,while elevated levels of total bilirubinand ALT also decreased.The difference in urea,direct bilirubin and ALP was not significantwhen infected rats were compared to rats in other groups.Conclusions:The ability of the plantto ameliorate the infection-induced biochemical changes calls for detailed investigation of thepotentials of the plant for antitrypanosomiasis drug delivery.
文摘Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei(T.brucei) on dam and offspring.Methods:Sixty female Albino rats(Rattus norvegicus) weighing between 130-170 g were used as animal model.The animals were divided as follows: 25 infected between 1-5 days post partum;10 infected unbred as positive controls;and 25 uninfected as negative controls.The following parameters were evaluated:packed cell volume (PCV),level of parasitaemia,survival time,litter size and litter weight at birth and on days 7, 14 and 21 post delivery,using conventional methods.Possible trans-mammary transmission of infection to litter through milk was also assessed.Results:The results showed a comparatively (P【0.05) higher mean PCV value for the uninfected negative control on the 8 day post infection compared with the infected groups which corresponded with the increasing level of parasitaemia in the two infected groups.Mean litter size and litter weights were higher(P【0.05) in the uninfected controls on the 21<sup>st</sup> day.Survival time in the infected groups were similar.No evidence of trans-mammary transfer of infection was recorded.Conclusion:T.brucei infection during immediate post partum period is detrimental to the dam and impairs growth of the offspring.
文摘Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wide range of therapies.The utilization of animals and plants products has presented therapeutic potential for identifying novel anti-trypanosomal drugs.This study evaluated toad venom for anti-trypanosomal potency in-vivo in Swiss mice.Toads were collected from July to August 2019.The acute oral toxicity and biochemical characterization of the toad venom were determined.The experimental mice were administered various doses(130 mg/kg,173 mg/kg and 217 mg/kg)of the toad venom crude extract and 0.75 mg/mL of Diamizan Plus standard drug for the treatment of trypanosomiasis,once daily for 3 days.The in-vivo anti-trypanosomal activity was evaluated by a curative test,after infecting the mice with Trypanosoma brucei brucei.The pre-patent period was 72 hours before treatment commenced.The overall results showed that trypanosomal load was highest in the control group while the group treated with Diamizan drug had the least trypanosomal load.As such,the mean trypanosomal load in relation to treatments showed a very high significant difference(P<0.05).Also,the mean trypanosomal load in Swiss mice in relation to the highest dosage of toad venom versus Diamizan drug showed a very high significant difference(P<0.05).The mean change in relation to the haematological parameters across treatments groups varied significantly(P<0.05)with the exception of Hb which showed no significant difference(P>0.05)across treatment groups.The over 50%reduction in the trypanosomal load in the 130 mg/kg group in comparison with the control group brings to bare the anti-trypanosomal potency of the toad venom.The anti-trypanosomal activity demonstrated by the toad venom has provided basis for development of new therapeutic agents from different toad species.The study recommends further studies(both in-vivo and in-vitro)followed by the characterization of the active compounds present in the toad venom responsible for the anti-tyrpanosomal activity observed alongside the management and conservation of these species.
文摘Apoptosis in single-cell organisms like Trypanosoma or Leishmania was characterized in several studies in the last few years [1]-[4]. Cell death in these caspase lacking protozoa is still poorly understood and a conclusive apoptotic pathway has not been identified so far. In the work presented here, we studied the effects of prostaglandin D2 and staurosporine induced cell death in blood-forms of Trypanosoma brucei in a time dependent manner and focused on the role of a nuclease similar to endonuclease G of higher eukaryotes. We found that these parasites undergo apoptotic cell death as demonstrated by the appearance of several canonical hallmarks of apoptosis in higher eukaryotes, but that different stimuli induce remarkable differences in the way these cells die. We compared the effects of prostaglandin D2 and staurosporine in trypanosomes with and without endonuclease G overexpression by flow cytometric and electron microscopic methods with the result that endonuclease G overexpression led to a significant modification of intracellular organelles and accelerated apoptotic cell death in prostaglandin D2 or staurosporine treated cells. Our results demonstrate that different stimuli induce apoptosis even in these ancient organisms in different caspase-independent ways. Whereas central processes of apoptosis like ROS formation, loss of mitochondrial membrane potential, endonuclease G release, phosphatidylserine exposure and DNA fragmentation appeared in the same chronology during treatment with either one of both drugs, other effects like cell cycle arrest or change of cell shape occurred only in the case of prostaglandin D2 or staurosporine treatment. We conclude from these results that trypanosomes react to stimuli of apoptosis with the concerted action of cellular responses but cannot control the final outcome if additional stress, as in the case of staurosporine, is superimposed.
文摘Human African trypanosomiasis (HAT) affects up to half a million people every year in sub-Saharan Africa. Interruption of transmission of the disease by early diagnosis and treatment is core to the control and eventual elimination of HAT. The routine diagnostic method for HAT is light microscopy of blood samples. The present study sought to evaluate the potential of TbgI2 and TbgI17 tandem repeat antigens as candidates for the diagnosis of Trypanosoma brucei rhodesiense. The expressed proteins were purified and the antigenic reactivity evaluation was done using multiplex assay using sera obtained from HAT patients. Receiver operating characteristic analysis showed that recombinant antigen, TbgI2 had high sensitivity for sera from patients infected with T. b. rhodesiense with the area under the curve being 0.577 and a sensitivity of 0.641 and specificity 0.650. The results suggest that TbgI2 is a potential biomarker for T. b. rhodesiense HAT serodiagnostic tests.
基金This work was supported by the National Key Research and Development Program of China(Grant Nos.2016YFC1202000,2016YFC1202002)by the International Development Research Center(IDRC),Canada(grant No.108100–001).
文摘Background:Human African trypanosomiasis(HAT)is one of the most complex parasitic diseases known to humankind.It usually occurs in endemic areas in Africa,but is occasionally detected in returning travelers and migrants in non-endemic countries.Case presentation:In August 2017,a case of HAT was diagnosed in China in a traveler returning from the Masai Mara area in Kenya and the Serengeti area in Tanzania.The traveler visited Africa from 23 July to 5 August,2017.Upon return to China,she developed a fever(on 8 August),and Trypanosoma brucei rhodesiense infection was confirmed by laboratory tests(on 14 August)including observation of parasites in blood films and by polymerase chain reaction.She was treated with pentamidine followed by suramin,and recovered 1 month later.Conclusions:This is the first imported rhodesiense HAT case reported in China.This case alerts clinical and public health workers to be aware of HAT in travelers,and expatriates and migrants who have visited at-risk areas in Africa.
文摘Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats.Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats.Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei.Results:Parasitaemia was recorded in Group B by(3.86±0.34)d and the peak of parasitaemia was observed at Day 5 post infection.Classical signs observed included squint eyes,raised whiskers,lethargy,no weight loss,pyrexia,isolation from the other rats,and starry hair coat.Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.
基金Supported by a grant from graduate school(GSEU 20RR0234/2011),Egerton University Faculty Research Committee.
文摘Objective:To establish the modulatory effects of coenzyme Q_(10)on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy(PTRE).Methods:Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q_(10)after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense(T.b.rhodesiense).The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE.Parasitaemia development,packed cell volume,haematological and pathological changes were determined.Results:A histological study in the brain tissue of T.b.rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups.A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q_(10)was administered.Furthermore,the mean tissue weight of spleen to body ratio in coenzyme Q_(10)supplemented group was significantly(P<0.05)different compared to un-supplemented groups,and clearly indicated that coenzyme Q_(10)prevented full blown splenomegaly pathogenesis by T.b.rhodesiense.A significant(P<0.05)increase in hemoglobin levels and red blood cells was observed in coenzyme Q_(10)mice compared to those infected and un-supplemented with coenzyme Q_(10).Conclusions:The capacity of coenzyme Q_(10)to alter the pathogenesis of T.b.rhodesiense infection in mice and following treatment with melarsoprol,may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.
文摘Objective:To determine the effect of Trypanosoma brucei(T.brucei)on blood sugar level of infected rats.Methods:The experiment was done with 42 albino rats grouped into 3 groups of 14 members each.Group A was uninfected(control group),Group B was infected with T.brucei and treated with diminazene aceturate,and Group C was infected with T.brucei and treated with imidocarb dipropionate.Blood samples were collected from the media canthus of the experimental rats on Days 0,1,2,3,4,5,6,7,8,9,10 for the assessment of change in blood sugar levels.The blood sugar levels were determined with a glucometer(Accu-chek active serial No.GN:10023338).Results:By 4 to 5 days post infection,there was a significant increase(P<0.05)in the blood sugar of Group B and Group C.By Day 6 post infection(Day 2 post treatment),no significant difference(P>0.05)was observed in the groups when compared with the control group till Day 12 of the experiment.Conclusions:T.brucei caused a significant increase in blood sugar of infected rats.
文摘Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10<sup>5</sup> Trypanosoma in normal saline.Five days when a high level of parasiteamia was established treatment commenced until ten days.The mice were treated with 10,20 and 40 mg/kg bt.of the extract and 5 and 10 mg/kg bt.of the fraction(F<sub>2</sub>),respectively for 5 days.Diminazene acelurate at the dose of 3.5 mg/kg bt.for two days was used as the reference drug.The level of parasitaemia and packed cell volume(PCV) of the animals estimated. Results:At doses of 10,20 and 40 mg/kg the crude extract showed a sharp reduction in the level of parasitaemia in mice compared with the untreated group.The mice treated with F,at doses of 5 and 10 mg/kg showed a sharp reduction in the level of parasitamia to zero in day 9,and a gradual recovery from the 12th day of treatment.This effect is comparable to that of the mice treated with 7 mg/kg of standard drug diminazene aceturate.The PCV of the treated showed a gradual decrease with time,but not as much as the untreated group.Phytochemical screening revealed the presence of glycosides,alkaloids,carbohydrates,tannins and proteins in the Abrus precatorius powder while F<sub>2</sub> was rich in alkaloids.Conclusions:This study shows that both the extract and the fractions of Abrus precatorius seeds exhibited a promising trypanocidal property.Alkaloids may be responsible for the observed activity.
文摘Objective:To investigated the prevalence of human African trypanosomiasis(HAT),a neglected tropical disease caused by Trypanosoma brucei gambiens in an endemic focus of Nigeria,as it relates to age,sex and occupational differences.Methods:A total of 474 human subjects were screened using card agglutination test for trypanosomiasis kit.Positive samples were further investigated for parasite positivity in blood/serum and cerebrospinal fluid(CSF).Results:Of the 474 screened,44(9.3%) were seropositive with seroprevalence of 22(9.6%) in Urhouka,14(9.5%) in Umeghe and 8(7.9%) for Ugonu.The number of seropositives,observed for weakly,moderately and strongly positives for the three communities were 4,7 and 11 in Urhouka,4,5 and 5 in Umeghe and 3,2 and 3 in Ugonu respectively.Among the 16 volunteers with detected parasite in their blood,4 of them were weakly positive,5 of them were moderately positive and 7 of them strongly positive.4 volunteers from Urhouka community were found parasites in their CSF and they were all strongly positive.The difference between the seroprevalence of males and females was not statistically significant(OR=1.14,95%CI=0.37-3.4,P】0.05).The prevalence difference between age group 21-30 years old and the youngest and oldest age groups was statistically significant(OR=3.5,95%CI= 1.08-12.57,P【0.05) but not significant for other age categories (P】0.05),It was observed that farmers had significantly higher prevalence of HAT infection as well as greater risk of Trypanosoma brucei gambiense infection than inhabitants with other occupations (OR=3.25,95%CI=0.99-11.79,P【0.05).Conclusions:Human activities such as farming and visits to the river have been identified as major risk factors to HAT.Also the breakdown of HAT control program has been advanced for the rise in HAT in Abraka,an endemic focus in Nigeria.
文摘Human African trypanosomiasis (HAT), or sleeping sickness, caused by Trypanosoma brucei gambiense, is associated with diverse clinical outcomes. Host’s genetic factors involved in immunity are potential factors that can regulate infection. Genetic polymorphisms within HLA-G could influence the level of HLA-G expression and therefore play a critical role in infection outcomes. The goal of our study was to investigate the association of 14 bp Indel HLA-G polymorphism with the susceptibility/resistance to HAT. DNA samples were collected from 119 cases, 221 controls and 43 seropositive individuals living in Ivorian HAT foci. The 14 bp Indel polymorphism was determined by PCR. Homozygous individuals for 14 bp insertion had a lower risk of progressing to active HAT (p = 0.012, OR = 0.27, 95% CI: 0.09 - 0.8). Moreover, the frequency of 14 bp insertion homozygous genotype was higher in the seropositive group (11%) than in the HAT cases group (3%) (p = 0.043, OR = 0.27, 95% CI: 0.07 - 0.99), which suggested a protective effect of 14 bp insertion homozygous genotype. Genetic polymorphisms in HLA-G may be associated with a variable risk to develop HAT. The 14 bp insertion appears to favour the occurrence of long-lasting T. b. gambiense latent infections.