Background:The speedy rate of change in the environmental and socio-economics factors may increase the incidence,prevalence and risk of schistosomiasis infections in Zambia.However,available information does not provi...Background:The speedy rate of change in the environmental and socio-economics factors may increase the incidence,prevalence and risk of schistosomiasis infections in Zambia.However,available information does not provide a comprehensive understanding of the biogeography and distribution of the disease,ecology and population dynamics of intermediate host snails.The current study used an information-theoretical approach to understand the biogeography and prevalence schistosomiasis and identified knowledge gaps that would be useful to improve policy towards surveillance and eradication of intermediate hosts snails in Zambia.Methods:To summarise the existing knowledge and build on past and present experiences of schistosomiasis epidemiology for effective disease control in Zambia,a systematic search of literature for the period 2000-2017 was done on PubMed,Google Scholar and EBSCOhost.Using the key words:‘Schistosomiasis’,‘Biomphalaria’,‘Bulinus’,‘Schistosoma mansoni’,‘Schistosoma haematobium’,and‘Zambia’,in combination with Booleans terms‘AND’and‘OR’,published reports/papers were obtained and reviewed independently for inclusion.Results:Thirteen papers published in English that fulfilled the inclusion criteria were selected for the final review.The papers suggest that the risk of infection has increased over the years and this has been attributed to environmental,socio-economic and demographic factors.Furthermore,schistosomiasis is endemic in many parts of the country with infection due to Schistosoma haematobium being more prevalent than that due to S.mansoni.This review also found that S.haematobium was linked to genital lesions,thus increasing risks of contracting other diseases such as HIV and cervical cancer.Conclusions:For both S.haematobium and S.mansoni,environmental,socio-economic,and demographic factors were influential in the transmission and prevalence of the disease and highlight the need for detailed knowledge on ecological modelling and mapping the distribution of the disease and intermediate host snails for effective implementation of control strategies.展开更多
Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood.In contrast,very little is known about such mechanisms in cases of malaria c...Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood.In contrast,very little is known about such mechanisms in cases of malaria co-infections with tissue-dwelling parasites.This is lack of knowledge is exacerbated by misdiagnosis,lack of pathognomonic clinical signs and the chronic nature of tissue-dwelling helminthic infections.A good understanding of the implications of tissuedwelling parasitic co-infections with malaria will contribute towards the improvement of the control and management of such co-infections in endemic areas.This review summarises and discusses current information available and gaps in research on malaria co-infection with gastro-intestinal helminths and tissue-dwelling parasites with emphasis on helminthic infections,in terms of the effects of migrating larval stages and intra and extracellular localisations of protozoan parasites and helminths in organs,tissues,and vascular and lymphatic circulations.展开更多
Background:Given that increase in temperature may alter host-parasite relationships,the anticipated rise in temperature due to global warming might change transmission patterns of certain diseases.However,the extent t...Background:Given that increase in temperature may alter host-parasite relationships,the anticipated rise in temperature due to global warming might change transmission patterns of certain diseases.However,the extent to which this will happen is not well understood.Methods:Using a host-parasite system involving Bulinus globosus and Schistosoma haematobium,we assessed the effect of temperature on snail fecundity,growth,survival and parasite development under laboratory conditions.Results:Our results show that temperature may have a non-linear effect on snail fecundity and snail growth.Snails maintained at 15.5℃ and 36.0℃ did not produce egg masses while those maintained at 25.8℃ laid 344 and 105 more egg masses than snails at 31.0℃ and 21.2℃,respectively.Attainment of patency led to a reduction in egg mass production among the snails.However,the reduction in fecundity for snails maintained at 21.2℃ occurred before snails started shedding cercariae.Parasite development was accelerated at high temperatures with snails maintained at 31.0℃ reaching patency after three weeks.Furthermore,snail growth rate was highest at 25.8℃ while it was inhibited at 15.5℃ and reduced at 31.0℃.Increase in temperature increased snail mortality rates.Snails maintained at 36.0℃ had the shortest survival time while those maintained at 15.5℃ had the longest survival time.Conclusions:We concluded that temperature influences fecunxdity,growth,survival and parasite development in the snail and thus dictates the time it takes the parasite to complete the life cycle.This has implications on transmission of schistosomiasis in the context of global warming.展开更多
Malaria is a global public health problem,with about 3.2 billion people at risk of infection.The populations at risk mainly reside in Africa,Asia and America,with African populations accounting for the largest burden ...Malaria is a global public health problem,with about 3.2 billion people at risk of infection.The populations at risk mainly reside in Africa,Asia and America,with African populations accounting for the largest burden of the disease.In 2013,close to 198 million malaria cases were reported,leading to 584,000 deaths.Much(90%)of the mortality rates were recorded from the World Health Organization(WHO)database in the African region and 78%of these occurred in children under the age of five.In Zimbabwe,approximately half of the population is at risk of infection with malaria.Insecticide residual spraying(IRS)has been documented as an effective way to control malaria and has been adopted globally by the WHO and national governments.However,both insecticide resistance and climate change threaten to reverse the progress made by IRS in malaria control.Resistance has been reported in all four classes of insecticides approved by the WHO for vector control intervention.Variability of environmental temperature is suspected to complicate the situation through alteration in the genetic structure,and enzyme and protein profiles of mosquitoes.In Zimbabwe,little research has been done on the interaction between climate change,temperature variability and insecticide resistance in malarial mosquitoes over time.Such information is important for informing policies on insecticide selection for IRS.We reviewed literature on insecticide sensitivity among malarial mosquitoes in Zimbabwe from 1972 to 2014.International peer-reviewed articles on insecticide sensitivity in Zimbabwe,published in English in this time period,were searched using MEDLINE®(PubMed),Google Scholar,Google and grey literature.Eight publications were eligible for the present study,with one of the articles being a review paper.Six articles covered insecticide resistance,while the other two articles,published in 2000,were about the absence of resistance.Contradicting resistance results were reported in 2014.The insecticide sensitivity status and distribution of insecticide resistance in mosquitoes are still under debate in Zimbabwe,as studies report differing results.The resistance trend in Zimbabwe is characterised by fluctuations in the status of the sensitivity of existing insecticides.Inconsistencies in data collection methods may be responsible for the inconsistencies in the results.None of the studies have determined a link between climate/temperature variability and insecticide resistance as yet.The current insecticide sensitivity status of mosquitoes still needs to be verified.展开更多
Background:Community Engagement(CE)in health research ensures that research is consistent with the sociocultural,political and economic contexts where the research is conducted.The greatest challenges for researchers ...Background:Community Engagement(CE)in health research ensures that research is consistent with the sociocultural,political and economic contexts where the research is conducted.The greatest challenges for researchers are the practical aspects of CE in multicentre health research.This study describes the CE in an ecohealth community-based research project focusing on two vulnerable and research naive rural communities.Methods:A qualitative,longitudinal multiple case study approach was used.Data was collected through Participatory Rural Appraisals,Focus Group Discussions,In-depth Interviews,and observations.Results:The two sites had different cultural values,research literacy levels,and political and administrative structures.The engagement process included 1)introductions to the administrative and political leaders of the area;2)establishing a community advisory mechanism;3)community empowerment and 4)initiating sustainable post-study activities.In both sites the study employed community liaison officers to facilitate the community entry and obtaining letters of permission.Both sites opted to form Community Advisory Boards as their main advisory mechanism together with direct advice from community leaders.Empowerment was achieved through the education of ordinary community members at biannual meetings,employment of community research assistants and utilising citizen science.Through the research assistants and the citizen science group,the study has managed to initiate activities that the community will continue to utilise after the study ends.General strategies developed are similar in principle,but implementation and emphasis of various aspects differed in the two communities.Conclusions:We conclude that it is critical that community engagement be consistent with community values and attitudes,and considers community resources and capacity.A CE strategy fully involving the community is constrained by community research literacy levels,time and resources,but creates a conducive research environment.展开更多
基金The writing of this review was made possible through the post-doctoral fellowship from the University of KwaZulu-Natal,College of Health Sciences that was awarded to Dr.Chester Kalinda。
文摘Background:The speedy rate of change in the environmental and socio-economics factors may increase the incidence,prevalence and risk of schistosomiasis infections in Zambia.However,available information does not provide a comprehensive understanding of the biogeography and distribution of the disease,ecology and population dynamics of intermediate host snails.The current study used an information-theoretical approach to understand the biogeography and prevalence schistosomiasis and identified knowledge gaps that would be useful to improve policy towards surveillance and eradication of intermediate hosts snails in Zambia.Methods:To summarise the existing knowledge and build on past and present experiences of schistosomiasis epidemiology for effective disease control in Zambia,a systematic search of literature for the period 2000-2017 was done on PubMed,Google Scholar and EBSCOhost.Using the key words:‘Schistosomiasis’,‘Biomphalaria’,‘Bulinus’,‘Schistosoma mansoni’,‘Schistosoma haematobium’,and‘Zambia’,in combination with Booleans terms‘AND’and‘OR’,published reports/papers were obtained and reviewed independently for inclusion.Results:Thirteen papers published in English that fulfilled the inclusion criteria were selected for the final review.The papers suggest that the risk of infection has increased over the years and this has been attributed to environmental,socio-economic and demographic factors.Furthermore,schistosomiasis is endemic in many parts of the country with infection due to Schistosoma haematobium being more prevalent than that due to S.mansoni.This review also found that S.haematobium was linked to genital lesions,thus increasing risks of contracting other diseases such as HIV and cervical cancer.Conclusions:For both S.haematobium and S.mansoni,environmental,socio-economic,and demographic factors were influential in the transmission and prevalence of the disease and highlight the need for detailed knowledge on ecological modelling and mapping the distribution of the disease and intermediate host snails for effective implementation of control strategies.
基金This study received financial support from the College of Health Sciences,University of KwaZulu-Natal through a PhD studentship bursary awarded to NWO.
文摘Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood.In contrast,very little is known about such mechanisms in cases of malaria co-infections with tissue-dwelling parasites.This is lack of knowledge is exacerbated by misdiagnosis,lack of pathognomonic clinical signs and the chronic nature of tissue-dwelling helminthic infections.A good understanding of the implications of tissuedwelling parasitic co-infections with malaria will contribute towards the improvement of the control and management of such co-infections in endemic areas.This review summarises and discusses current information available and gaps in research on malaria co-infection with gastro-intestinal helminths and tissue-dwelling parasites with emphasis on helminthic infections,in terms of the effects of migrating larval stages and intra and extracellular localisations of protozoan parasites and helminths in organs,tissues,and vascular and lymphatic circulations.
基金The study received financial support from University of KwaZulu-Natal College of Health Sciences through the student scholarship programme,and from United Nations International Children's Fund/United Nations Development Programme/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseasesfrom the Canadian International Development Research Centre through their support towards a Malaria and Bilharzia in Southern Africa project.
文摘Background:Given that increase in temperature may alter host-parasite relationships,the anticipated rise in temperature due to global warming might change transmission patterns of certain diseases.However,the extent to which this will happen is not well understood.Methods:Using a host-parasite system involving Bulinus globosus and Schistosoma haematobium,we assessed the effect of temperature on snail fecundity,growth,survival and parasite development under laboratory conditions.Results:Our results show that temperature may have a non-linear effect on snail fecundity and snail growth.Snails maintained at 15.5℃ and 36.0℃ did not produce egg masses while those maintained at 25.8℃ laid 344 and 105 more egg masses than snails at 31.0℃ and 21.2℃,respectively.Attainment of patency led to a reduction in egg mass production among the snails.However,the reduction in fecundity for snails maintained at 21.2℃ occurred before snails started shedding cercariae.Parasite development was accelerated at high temperatures with snails maintained at 31.0℃ reaching patency after three weeks.Furthermore,snail growth rate was highest at 25.8℃ while it was inhibited at 15.5℃ and reduced at 31.0℃.Increase in temperature increased snail mortality rates.Snails maintained at 36.0℃ had the shortest survival time while those maintained at 15.5℃ had the longest survival time.Conclusions:We concluded that temperature influences fecunxdity,growth,survival and parasite development in the snail and thus dictates the time it takes the parasite to complete the life cycle.This has implications on transmission of schistosomiasis in the context of global warming.
基金This study was financially supported by the College of Health Sciences of the University of KwaZulu-Natal through PhD studentship bursary awarded to the first authorThe WHO TDR and the Canadian IDRC are also thanked for their funding.
文摘Malaria is a global public health problem,with about 3.2 billion people at risk of infection.The populations at risk mainly reside in Africa,Asia and America,with African populations accounting for the largest burden of the disease.In 2013,close to 198 million malaria cases were reported,leading to 584,000 deaths.Much(90%)of the mortality rates were recorded from the World Health Organization(WHO)database in the African region and 78%of these occurred in children under the age of five.In Zimbabwe,approximately half of the population is at risk of infection with malaria.Insecticide residual spraying(IRS)has been documented as an effective way to control malaria and has been adopted globally by the WHO and national governments.However,both insecticide resistance and climate change threaten to reverse the progress made by IRS in malaria control.Resistance has been reported in all four classes of insecticides approved by the WHO for vector control intervention.Variability of environmental temperature is suspected to complicate the situation through alteration in the genetic structure,and enzyme and protein profiles of mosquitoes.In Zimbabwe,little research has been done on the interaction between climate change,temperature variability and insecticide resistance in malarial mosquitoes over time.Such information is important for informing policies on insecticide selection for IRS.We reviewed literature on insecticide sensitivity among malarial mosquitoes in Zimbabwe from 1972 to 2014.International peer-reviewed articles on insecticide sensitivity in Zimbabwe,published in English in this time period,were searched using MEDLINE®(PubMed),Google Scholar,Google and grey literature.Eight publications were eligible for the present study,with one of the articles being a review paper.Six articles covered insecticide resistance,while the other two articles,published in 2000,were about the absence of resistance.Contradicting resistance results were reported in 2014.The insecticide sensitivity status and distribution of insecticide resistance in mosquitoes are still under debate in Zimbabwe,as studies report differing results.The resistance trend in Zimbabwe is characterised by fluctuations in the status of the sensitivity of existing insecticides.Inconsistencies in data collection methods may be responsible for the inconsistencies in the results.None of the studies have determined a link between climate/temperature variability and insecticide resistance as yet.The current insecticide sensitivity status of mosquitoes still needs to be verified.
基金This study was financially supported by the College of Health Sciences of the University of KwaZulu-Natal through a PhD studentship bursary awarded to the first authorThe WHO TDR and the Canadian IDRC are also thanked for their funding。
文摘Background:Community Engagement(CE)in health research ensures that research is consistent with the sociocultural,political and economic contexts where the research is conducted.The greatest challenges for researchers are the practical aspects of CE in multicentre health research.This study describes the CE in an ecohealth community-based research project focusing on two vulnerable and research naive rural communities.Methods:A qualitative,longitudinal multiple case study approach was used.Data was collected through Participatory Rural Appraisals,Focus Group Discussions,In-depth Interviews,and observations.Results:The two sites had different cultural values,research literacy levels,and political and administrative structures.The engagement process included 1)introductions to the administrative and political leaders of the area;2)establishing a community advisory mechanism;3)community empowerment and 4)initiating sustainable post-study activities.In both sites the study employed community liaison officers to facilitate the community entry and obtaining letters of permission.Both sites opted to form Community Advisory Boards as their main advisory mechanism together with direct advice from community leaders.Empowerment was achieved through the education of ordinary community members at biannual meetings,employment of community research assistants and utilising citizen science.Through the research assistants and the citizen science group,the study has managed to initiate activities that the community will continue to utilise after the study ends.General strategies developed are similar in principle,but implementation and emphasis of various aspects differed in the two communities.Conclusions:We conclude that it is critical that community engagement be consistent with community values and attitudes,and considers community resources and capacity.A CE strategy fully involving the community is constrained by community research literacy levels,time and resources,but creates a conducive research environment.
