SUMMARY


That humans in endemic areas become immune to malaria offers encouragement to the idea of developing protective vaccines However natural immunity is relatively inefficient, being bought at the cost of substantial childhood mortality, and current vaccines are only partially protective Understanding potential targets and mechanisms of protective immunity is important in the development and evaluation of future vaccines Some of the problems in identifying such targets and mechanisms in humans naturally exposed to malaria may stem from conceptual and methodological issues related to defining who in a population is susceptible, problems in defining immune responsiveness at single time points and issues related to antigenic polymorphism, as well as the failure of many current approaches to examine functional aspects of the immune response Protective immune responses may be directed to the pre erythrocytic parasite, to the free merozoite of the blood stage parasite or to new antigens induced on the infected red cell surface Tackling the methodological issues of defining protection and immune response, together with studies that combine functional assays with new approaches such as allelic exchange and gene knock out offer opportunities for better defining key targets and mechanisms

Immune effector mechanisms in malaria.

Malaria is a significant public health problem in more than 100 countries and causes an estimated 200 million new infections every year. Despite the significant effort to eradicate this dangerous disease, lack of complete knowledge of its physiopathology compromises the success in this enterprise. In this paper we review oxidative stress mechanisms involved in the disease and discuss the potential benefits of antioxidant supplementation as an adjuvant antimalarial strategy.

https://www.mdpi.com/1422-0067/13/12/16346/pdf

Oxidative Stress in Malaria

a b s t r a c t Schistosomiasis, a neglected tropical disease of poverty ranks second among the most widespread parasitic disease in various nations in sub-Saharan Africa. Neglected tropical diseases are causes of about 534,000 deaths annually in sub-Saharan Africa and an estimated 57 million disability-adjusted life-years are lost annually due to the neglected tropical diseases. The neglected tropical diseases exert great health, social and financial burden on economies of households and governments. Schistosomiasis has profound negative effects on child development, outcome of pregnancy, and agricultural productivity, thus a key reason why the “bottom 500 million” inhabitants of sub-Saharan Africa continue to live in poverty. In 2008, 17.5 million people were treated globally for schistosomiasis, 11.7 million of those treated were from sub-Saharan Africa. This enervating disease has been successfully eradicated in Japan, as well as in Tunisia. Morocco and some Caribbean Island countries have made significant progress on control and management of this disease. Brazil, China and Egypt are taking steps towards elimination of the disease, while most sub-Saharan countries are still groaning under the burden of the disease. Various factors are responsible for the continuous and persistent transmission of schistosomiasis in sub-Saharan Africa. These include climatic changes and global warming, proximity to water bodies, irrigation and dam construction as well as socio-economic factors such as occupational activities and poverty. The morbidity and mortality caused by this disease cannot be overemphasized. This review is an exposition of human schistosomiasis as it affects the inhabitants of various communities in sub-Sahara African countries. It is hoped this will bring a re-awakening towards efforts to combat this impoverishing disease in terms of vaccines development, alternative drug design, as well as new point-of-care diagnostics.

/pdf/impact-of-human-schistosomiasis-in-sub-saharan-africa-2597biq0pq.pdf

Impact of human schistosomiasis in sub-Saharan Africa

Schistosomiasis is a major neglected tropical disease that afflicts more than 240 million people, including many children and young adults, in the tropics and subtropics. The disease is characterized by chronic infections with significant residual morbidity and is of considerable public health importance, with substantial socioeconomic impacts on impoverished communities. Morbidity reduction and eventual elimination through integrated intervention measures are the focuses of current schistosomiasis control programs. Precise diagnosis of schistosome infections, in both mammalian and snail intermediate hosts, will play a pivotal role in achieving these goals. Nevertheless, despite extensive efforts over several decades, the search for sensitive and specific diagnostics for schistosomiasis is ongoing. Here we review the area, paying attention to earlier approaches but emphasizing recent developments in the search for new diagnostics for schistosomiasis with practical applications in the research laboratory, the clinic, and the field. Careful and rigorous validation of these assays and their cost-effectiveness will be needed, however, prior to their adoption in support of policy decisions for national public health programs aimed at the control and elimination of schistosomiasis.

Advances in the Diagnosis of Human Schistosomiasis

Publisher Summary This chapter discusses the studies on the biology, life history, infectivity, immunology, pathology, epidemiology, physiology, and biochemistry of Echinostoma . Some studies on other genera of Echinostomatidae are considered as they relate to Echinostoma. The systematics of the 37-collar-spined Echinostoma in the E. revoluturn group is discussed and is based on morphological, biometrical, isoenzymatical, and biological characteristics. The chapter focuses on E. trivolvis, E. caproni, and E. revolutum. Echinostome adults are cosmopolitan, hermaphroditic digeneans that live in the intestines and bile ducts of numerous vertebrate hosts, particularly, aquatic or semi-aquatic birds and mammals. Results derived from the experimental infection of laboratory rodents have provided insight into the pathogenesis of echinostomes. The diagnosis of echinostomiasis is made by recovering the eggs in the feces. The time of deposition of eggs in the feces will vary between species. Species diagnosis is based mainly on the morphological study of the adult worm, which can be obtained after anthelmintic treatment. The transplantation studies and cultivation of Echinostoma in vivo and in vitro are also discussed. The use of echinostomes in physiological, biochemical, and behavioral studies is an untapped resource. Many of the studies done on E. trivolvis need to be performed on E. caproni , E. revohturn , and other echinostomes for comparative purposes. The gross and histopathological effects of echinostome infections are well documented in experimental infections in mice and hamsters.

Echinostoma and echinostomiasis.

Malaria merozoite surface protein 1 (MSP1) is cleaved in an essential step during erythrocyte invasion. The responses of children to natural malaria infection included antibodies that inhibit this cleavage and others that block the binding of these inhibitory antibodies. There was no correlation between the titer of the antibody to the 19-kDa fragment of MSP1 and its inhibitory activity. These findings have implications for the design of MSP1-based vaccines.

The Human Immune Response to Plasmodium falciparum Includes Both Antibodies That Inhibit Merozoite Surface Protein 1 Secondary Processing and Blocking Antibodies

Summary The current status of urinary schistosomiasis was assessed in Ibadan, an urban community in south-western Nigeria. Of 1331 children examined for eggs of S. haematobium in their urine, 17.4% were infected. Prevalence in postprimary schoolchildren was significantly (P 50 eggs/10 ml urine. 2.2% excreted S. mansoni eggs in urine. Water contact activities were more frequent (P < 0.01) in males (31.8%) than females (38.2%). Nine species of snails were encountered, with B. (p) globosus being the the most abundant and widespread. These results show that urinary schistosomiasis is still being actively being transmitted in Ibadan.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-3156.1999.00388.x

Urinary schistosomiasis among schoolchildren in Ibadan, an urban community in south-western Nigeria

Background & objectives: Oyo is an urban community in Oyo state of south-western Nigeria and it is holoendemic for malaria. Information was collected on the knowledge, attitudes and practices (KAP) of inhabitants of Oyo town in relation to malaria. Methods: A cross-sectional survey of 192 households with the aid of self- or researcher-administered questionnaires was carried out to identify factors associated with the disease in the area. Results: About 93.2% (n=192) of respondents recognized mosquito bites as the cause of malaria. A small proportion of children (13.7%) and adults (5.3%) received prompt treatment; however, more adults (65.8%) got correct dosage of antimalarials than children (38.7%). About 90% of suspected malaria cases in children and adults were first treated at home with local herbs or drugs, purchased from medicine stores. The use of insecticide-treated nets (ITNs) was scarce as only 16.7% of households used them for their children. Other reported malaria prevention methods include the use of insecticides (79.7%) and herbs (44.3%). In all, 17 (8.9%) of households did not have screening nets on their windows and 6.3% of 175 households with screening nets on their windows had rusty and torn nets. The level of education of heads of households was a strong predictor of positive malaria-related KAP. Window types and environmental hygiene were associated with prevalence of malaria in households. Interpretation & conclusion: The control of malaria cannot be achieved without full involvement of the affected communities; the available tools for control can only be effective and sustainable if the local communities are mobilized and empowered with knowledge. It is suggested that health education campaigns be intensified; chemist shop-keepers and mothers being important target groups.

Knowledge, attitudes and practices about malaria in an urban community in south-western Nigeria.

Establishment, survival, and fecundity in Echinostoma caproni (Trematoda) infections in NMRI mice

Etude de la reponse regulatrice de souris a des infestations secondaires et repetees de E.c. et des effets de la coinfection avec N.d..

Alexander B. Odaibo

Papers

The Human Immune Response to Plasmodium falciparum Includes Both Antibodies That Inhibit Merozoite Surface Protein 1 Secondary Processing and Blocking Antibodies

Urinary schistosomiasis among schoolchildren in Ibadan, an urban community in south-western Nigeria

Knowledge, attitudes and practices about malaria in an urban community in south-western Nigeria.

Establishment, survival, and fecundity in Echinostoma caproni (Trematoda) infections in NMRI mice

Further studies on the population regulation in Echinostoma caproni infections in NMRI mice