ABSTRACT
Vaccination against Plasmodium falciparum with attenuated sporozoites is the goal of the US Navy's Malaria Vaccine Program. One requirement in the development of this vaccine is an immunological test to study the sporozoite antigen and immune responses it induces. Using an indirect fluorescent antibody test (IFAT) and P. berghei in the mouse or rat as a model, we have made significant progress toward this goal. Four antigens were detected in vaccine preparations: sporozoite-specific antigens, mosquito antigens, antigens on the sporozoite that are common to erythrocytic stages, and bovine serum albumm, an antigenic element of the isolation medium no longer employed. The IFAT was a reliable monitor of vaccination in a mouse and rat model in conjunction with protection to challenge. The test was a sensitive monitor of vaccine quality. Anamnestic responses to bites of infected mosquitos were detected in mice previously immunized with irradiated sporozoites.
Subject(s)
Apicomplexa/immunology , Malaria/immunology , Plasmodium falciparum/immunology , Vaccination , Animals , Antigen-Antibody Reactions , Apicomplexa/metabolism , Fluorescent Antibody Technique , Ultraviolet RaysABSTRACT
The effects of primary, patent Plasmodium berghei infection in Sprague-Dawley rats during pregnancy upon the course of infection and the humoral antibody response to malaria in their offspring were examined. Malaria specific antibody determined by an indirect fluorescent antibody test correlated well with the parasitologic profiles of each experimental group. Utilization of foster mother groups indicated passive transfer of protective antibody through milk. Evidence for in utero sensitization by soluble malaria antigens was shown by an anamnestic-like antibody response during subsequent infection of offspring from infected mothers.
Subject(s)
Antibody Formation , Malaria/immunology , Maternal-Fetal Exchange , Animals , Animals, Newborn , Erythrocytes/parasitology , Female , Malaria/parasitology , Plasmodium berghei/immunology , Pregnancy , RatsABSTRACT
Five thousand and forty-six smears from 352 species of birds in Ethiopia were examined for blood parasites in an attempt to provide base-line data, to indicate fruitful areas for further study, on avian hematozoa. The prevalence of infection and the parasites found, with particular reference to Plasmodium, are discussed. At least 22 parasite species were recognized.
Subject(s)
Animals, Wild/parasitology , Bird Diseases/epidemiology , Parasitic Diseases, Animal/epidemiology , Animals , Bird Diseases/blood , Bird Diseases/parasitology , Birds , Ethiopia/epidemiology , Female , Male , Parasitic Diseases, Animal/blood , Seroepidemiologic Studies , Species SpecificityABSTRACT
Field trials were performed in two areas of Ethiopia with the Rieckmann in vitro test for chloroquine sensitivity of Plasmodium falciparum. Blood cultures from 82 test subjects showed growth of trophozoites to the schizont stage in control vials. Growth in test vials occurred in 21 cultures incubated with chloroquine at concentrations of 0.5 nanomoles or more per ml of blood. In vitro results confirm previous results obtained with an in vivo test.
Subject(s)
Chloroquine/pharmacology , Drug Resistance, Microbial , Plasmodium falciparum/drug effects , Ethiopia , In Vitro Techniques , Microbial Sensitivity TestsABSTRACT
The in vivo response of Plasmodium falciparum to the WHO single test dose (10 mg/kg body weight) of chloroquine base was examined in Ethiopia at four localities where malaria was meso- or hyperendemic. Parasitemias cleared by the 3rd day after chloroquine administration in all of the 150 test subjects. No recrudescences were detected during the 6-day or 11-day follow-up periods. The value of the in vivo test was severely limited by the inability to quarantine subjects and follow them for the 28-day period recommended by the World Health Organization.
