Antigens, Protozoan

Publication Title: 
European Journal of Immunology

Antibodies (Abs) are critical for immunity to malaria. However, Plasmodium falciparum specific Abs decline rapidly in absence of reinfection, suggesting impaired immunological memory. This study determines whether residents of Sweden that were treated for malaria following international travel maintained long-lasting malaria-specific Abs and memory B cells (MBCs).

Author(s): 
Ndungu, Francis M.
Lundblom, Klara
Rono, Josea
Illingworth, Joseph
Eriksson, Sara
F‰rnert, Anna
Publication Title: 
Blood

Ring-infected erythrocyte surface antigen (RESA)-positive, Plasmodium falciparum-negative red blood cells (RBCs) are cells from which the malaria parasite has been removed by the host without the destruction of the erythrocyte ("pitting"). The survival of RESA-RBCs in vivo was assessed in 14 severe and 6 uncomplicated falciparum malaria patients.

Author(s): 
Newton, P. N.
Chotivanich, K.
Chierakul, W.
Ruangveerayuth, R.
Teerapong, P.
Silamut, K.
Looareesuwan, S.
White, N. J.
Publication Title: 
The Journal of Infectious Diseases

In acute malaria, red blood cells (RBCs) that have been parasitized, but no longer contain a malaria parasite, are found in the circulation (ring-infected erythrocyte surface antigen [RESA]-RBCs). These are thought to arise by splenic removal of dead or damaged intraerythrocytic parasites and return of the intact RBCs to the circulation.

Author(s): 
Chotivanich, Kesinee
Udomsangpetch, Rachanee
McGready, Rose
Proux, Stephane
Newton, Paul
Pukrittayakamee, Sasithon
Looareesuwan, Sornchai
White, Nicholas J.
Publication Title: 
The American Journal of Tropical Medicine and Hygiene

Genotyping frequently is used to distinguish recrudescent from new infections in antimalarial drug efficacy trials, but methodology and interpretation of results have not been standardized. We compared the utility of polymorphisms within 3 Plasmodium falciparum genes during a longitudinal trial in Kampala, Uganda. Merozoite surface protein-1 (msp-1) and merozoite surface protein-2 (msp-2) revealed greater diversity than glutamate-rich protein. Genotypes based on msp-1, msp-2, and all 3 genes combined were compared for 394 initial and subsequent isolates.

Author(s): 
Cattamanchi, Adithya
Kyabayinze, Daniel
Hubbard, Alan
Rosenthal, Philip J.
Dorsey, Grant
Publication Title: 
The American Journal of Tropical Medicine and Hygiene

We evaluated the ICT Malaria P.f./P.v. immunochromatographic test for the detection of the panmalarial antigen (PMA) using a rodent malaria model. Mice were infected with Plasmodium berghei by mosquito bite, and blood was examined by microscopy and the ICT test. Treatment with artemether was started when the parasite density exceeded 70,000/microL. The ICT PMA band appeared when the parasite density was more than 2,000/microL, but it continued to be positive after the parasitemia became negative in response to the drug treatment.

Author(s): 
Arai, Meiji
Ishii, Akira
Matsuoka, Hiroyuki
Publication Title: 
Tropical medicine & international health: TM & IH

Molecular genotyping of baseline and post-treatment recurrent Plasmodium falciparum is recommended to distinguish recrudescent from new infections. However, genotyping performance and adjustment of treatment outcomes have not been evaluated in large field trials. Parasitological outcomes were assessed in nine double-blinded trials of uncomplicated P. falciparum malaria in African children treated with artesunate/placebo plus standard monotherapies. Day 28 failure rates were adjusted by stepwise genotyping the P.

Author(s): 
Mugittu, Kefas
Adjuik, Martin
Snounou, Georges
Ntoumi, Francine
Taylor, Walter
Mshinda, Hassan
Olliaro, Piero
Beck, Hans-Peter
Publication Title: 
The Journal of Infectious Diseases

We assessed the influence that consecutive-day blood sampling, compared with single-day blood sampling, had on polymerase chain reaction (PCR)-adjusted parasitological cure after stepwise genotyping of merozoite surface proteins 2 (msp2) and 1 (msp1) in 106 children in Tanzania who had uncomplicated falciparum malaria treated with either sulfadoxine-pyrimethamine or artemether-lumefantrine; 78 of these children developed recurrent parasitemia during the 42-day follow-up period.

Author(s): 
Mårtensson, Andreas
Ngasala, Billy
Ursing, Johan
Isabel Veiga, M.
Wiklund, Lisa
Membi, Christopher
Montgomery, Scott M.
Premji, Zul
Färnert, Anna
Björkman, Anders
Publication Title: 
JAMA

CONTEXT: Improving the accuracy of malaria diagnosis with rapid antigen-detection diagnostic tests (RDTs) has been proposed as an approach for reducing overtreatment of malaria in the current era of widespread implementation of artemisinin-based combination therapy in sub-Saharan Africa. OBJECTIVE: To assess the association between use of microscopy and RDT and the prescription of antimalarials.

Author(s): 
Hamer, Davidson H.
Ndhlovu, Micky
Zurovac, Dejan
Fox, Matthew
Yeboah-Antwi, Kojo
Chanda, Pascalina
Sipilinyambe, Naawa
Simon, Jonathon L.
Snow, Robert W.
Publication Title: 
Malaria Journal

BACKGROUND: A combination of artesunate (AS) plus sulphadoxine/pyrimethamine (SP) as first-line and artemether-lumefantrine (AL) as second-line treatment are currently recommended against uncomplicated P. falciparum infection in Sudan. However, there is limited information on the efficacy of ACTs in the country and only one report of PCR-corrected results for AS/SP only. METHODS: The WHO protocol for the assessment of antimalarial drug efficacy for the treatment of uncomplicated falciparum malaria was employed.

Author(s): 
Mukhtar, Ebtihal A.
Gadalla, Nahla B.
El-Zaki, Salah-Eldin G.
Mukhtar, Izdihar
Mansour, Fathi A.
Babiker, Ahmed
El-Sayed, Badria B.
Publication Title: 
The American Journal of Tropical Medicine and Hygiene

The interaction between Plasmodium vivax Duffy binding protein II (PvDBPII) and human erythrocyte Duffy antigen is necessary for blood stage infections. However, PvDBPII is highly polymorphic. We recently observed that certain recombinant DBPII variants bind better to erythrocytes in vitro. To examine the hypothesis that haplotypes with enhanced binding have increased parasitemia levels, we followed 206 Papua New Guinean children biweekly for six months with a total of 713 P. vivax samples genotyped.

Author(s): 
Cole-Tobian, Jennifer L.
Michon, Pascal
Dabod, Elijah
Mueller, Ivo
King, Christopher L.

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