Immune Response Regulation in People Infected Concurrently With Malarial and Filarial Parasites
Condition: Malaria; Filarial Infection
MeSH terms: Infections
Study type: Observational

Summary: 
      This study, conducted by NIH and the University of Bamako in Mali, Africa, will study the
      effect of concurrent infections with malaria and filariasis on patients' immune response.
      Lymphatic filariasis is caused by infection with very small parasitic worms called Wuchereria
      bancrofti that are acquired from mosquitoes. The worms may cause no illness in many who are
      infected, but is some, they can cause swelling of the arms, legs, breast and genitalia, which
      may progress to permanent swelling referred to as elephantiasis. Malaria is caused by
      Plasmodium falciparum, another parasite that is spread by mosquitoes. It can cause fevers,
      headaches, body aches and weakness, and, if untreated, it can cause severe illness and death.

      The 8-month study will analyze measures of immune function in blood cells from people with or
      without filarial infections who become infected with malaria. The goal of the studies is to
      see if having a filarial worm infection affects immunity against malaria. Results of analysis
      of immune function in persons with malaria but without filaria infections will be compared
      with those harboring both filaria and malaria infections and also with results from healthy
      control subjects.

      Healthy individuals and patients with malaria and filarial infections between 1 and 8 years
      of age and between 18 to 65 years of age who live in N'Tessoni and healthy individuals living
      in Bamako, Mali (controls), may be eligible for this study.

      Participants have blood samples collected as follows during the study:

        -  A blood sample will be collected at the beginning of the study. Individuals found to
           have the filarial worm infection have a second sample drawn at nighttime when the
           filarial worms are present in the blood. Treatment for filaria infection will be offered
           to all infected individuals at the end of the study.

        -  A second sample will be collected during malaria season. Subjects will be interviewed
           about their health during the malaria season and re-tested for filarial and malaria
           infections with a finger-prick test. Those who test positive for malaria will be offered
           treatment to begin immediately after collection of the donated blood sample..

        -  A third sample will be collected after the end of the malaria season. Subjects will be
           interviewed again about their health and re-tested for filarial and malaria infections
           with a finger prick test. Those who have positive results for either infection will be
           offered treatment after collec...
    

Detailed description: 
      Residents of malaria-endemic regions are frequently exposed to a variety of other parasites
      concurrently with malarial parasites. In Mali, lymphatic filariasis co-exists in several
      regions highly endemic for malaria. Because of the chronicity of filarial infections and an
      associated bias towards the development of an adaptive immune response dominated by Th2
      cytokines, a pre-existing filarial infection has the potential to alter the immune response
      towards incoming malarial parasites, clearance of which are considered to be dependent on a
      robust Th1 response. Conversely, immune responses to filarial parasites may be modulated in
      the presence of malarial parasites. The goal of this study is to determine the effect of
      concurrent infections with malarial and filarial parasites on innate and adaptive immune
      responses to homologous and heterologous antigens. We will characterize the responses of
      peripheral blood mononuclear cells to antigens derived from both filarial (Wuchereria
      bancrofti) and malarial (Plasmodium falciparum) parasites in groups of individuals with or
      without filarial infections and follow them through a malaria transmission season, when they
      are repeatedly exposed to malarial parasites, to determine how co-infection with the filarial
      parasite affects the cellular and humoral responses to malarial and filarial antigens. These
      studies may provide the basis for modifying treatment strategies of mass treatment of malaria
      in regions co-endemic for lymphatic filariasis.
    

Keywords: Immune Regulation; Co-Infection; Filariasis; Immunology; Filarial Infection