Epidemiology of Plasmodium-Helminth coinfection in Africa: potential impact on anaemia and prospects for combining control.

London School of Hygiene and Tropical Medicine, Kepel Street, London, United Kingdom.
The American journal of tropical medicine and hygiene (Impact Factor: 2.7). 01/2008; 77(6 Suppl):88-98.
Source: PubMed


Human co-infection with Plasmodium falciparum and helminths is ubiquitous throughout Africa, although its public health significance remains a topic for which there are many unknowns. In this review, we adopted an empirical approach to studying the geography and epidemiology of co-infection and associations between patterns of co-infection and hemoglobin in different age groups. Analysis highlights the extensive geographic overlap between P. falciparum and the major human helminth infections in Africa, with the population at coincident risk of infection greatest for hookworm. Age infection profiles indicate that school-age children are at the highest risk of co-infection, and re-analysis of existing data suggests that co-infection with P. falciparum and hookworm has an additive impact on hemoglobin, exacerbating anemia-related malarial disease burden. We suggest that both school-age children and pregnant women--groups which have the highest risk of anemia--would benefit from an integrated approach to malaria and helminth control.

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Available from: Peter J. Hotez
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    • "Human infections with these organisms remain prevalent in countries where the malaria parasite is also endemic [2]. Consequently , coinfections with both parasites occur frequently [3] [4]. These interactions could have potential fitness implications for both the host (morbidity and/or mortality) and the parasite (transmission). "
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    ABSTRACT: More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.
    Full-text · Article · Sep 2014 · BioMed Research International
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    • "prehensively investigated, with contradictory evidence (Douglas et al. 2012). In a study from the same area of this study, it has been suggested that helminthic infection leads to a less severe decrease in Hb concentration during acute P. vivax episodes in children (Melo et al. 2010), while in most P. falciparum studies, co-infection with hookworms was found to contribute synergistically to increased risk of anaemia (Stoltzfus et al. 2000, Brooker et al. 2007), illustrating the need to further investigate this association. Although the prevalence of glucose-6-phos- phate deficiency and haemoglobinopathies is presumed to be low in the Brazilian western Amazon Region (Ha-Haematology and Haemotherapy Foundation, unpublished observations), the well-established knowledge of their influence on the clinical epidemiology of malaria (Mason et al. 2007, Taylor et al. 2012), highlights the need for these factors to be assessed in future studies. "
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    ABSTRACT: Anaemia is amongst the major complications of malaria, a major public health problem in the Amazon Region in Latin America. We examined the haemoglobin (Hb) concentrations of malaria-infected patients and compared it to that of malaria-negative febrile patients and afebrile controls. The haematological parameters of febrile patients who had a thick-blood-smear performed at an infectious diseases reference centre of the Brazilian Amazon between December 2009-January 2012 were retrieved together with clinical data. An afebrile community control group was composed from a survey performed in a malaria-endemic area. Hb concentrations and anaemia prevalence were analysed according to clinical-epidemiological status and demographic characteristics. In total, 7,831 observations were included. Patients with Plasmodium falciparum infection had lower mean Hb concentrations (10.5 g/dL) followed by P. vivax-infected individuals (12.4 g/dL), community controls (12.8 g/dL) and malaria-negative febrile patients (13.1 g/dL) (p < 0.001). Age, gender and clinical-epidemiological status were strong independent predictors for both outcomes. Amongst malaria-infected individuals, women in the reproductive age had considerably lower Hb concentrations. In this moderate transmission intensity setting, both vivax and falciparum malaria are associated with reduced Hb concentrations and risk of anaemia throughout a wide age range.
    Full-text · Article · Aug 2014 · Memórias do Instituto Oswaldo Cruz
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    • "Malaria and helminth infections are two of the major causes of mortality and morbidity in developing countries (Brooker et al. 2007; Hotez and Kamath 2009; Mwangi et al. 2006). Both infections are highly endemic in tropical and sub tropical areas (Adegnika and Kremsner 2012; Akue et al. 2011; Brooker et al. 2007). In the tropics, Sub Saharan Africa (SSA) bears the heaviest burden of Plasmodium spss. "
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    ABSTRACT: Background Malaria and helminth co infection are common in tropical and subtropical areas where they affect the life of millions of people. While both helminth and malaria parasites have immunomodulatory activities, little is known about the consequence of co-infections on malaria antigen specific immune responses. Method/Design This study will be conducted in two rural areas of the Moyen Ogooué province in Gabon, endemic for both Plasmodium falciparum and Schistosoma haematobium infections. Participants, 5 to 50 years old, will be enrolled and grouped according to their infection status. S. haematobium and malaria parasites will be detected, demographic and clinical data will be recorded and blood will be collected for hematological as well as for immunological assays. The level of antibody specific to Plasmodium falciparum blood stage and gametocyte antigens will be measured using ELISA. PBMC will be isolated for phenotyping of different T cell subsets ex vivo by flow cytometry and for culture and cytokine response assessment. Discussion We will provide a comprehensive picture of the interaction between schistosomes and malaria parasites which co-localize in peripheral blood. We will test the hypothesis that schistosome infection has an impact on specific humoral as well as on cellular immune responses to malaria antigens.
    Full-text · Article · Jul 2014 · SpringerPlus
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