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Plasmodium vivax

Genetic polymorphism and natural selection of circumsporozoite protein in Myanmar Plasmodium vivax

September 8, 2020 - 11:46 -- Open Access
Author(s): 
Tuấn Cường Võ, Hương Giang Lê, Jung-Mi Kang, Mya Moe, Haung Naw, Moe Kyaw Myint, Jinyoung Lee, Woon-Mok Sohn, Tong-Soo Kim and Byoung-Kuk Na
Reference: 
Malaria Journal 2020 19:303, 4 September 2020

Circumsporozoite surface protein (CSP) of malaria parasites has been recognized as one of the leading vaccine candidates. Clinical trials of vaccines for vivax malaria incorporating Plasmodium vivax CSP (PvCSP) have demonstrated their effectiveness in preventing malaria, at least in part. However, genetic diversity of pvcsp in the natural population remains a major concern.

Not Open Access | Measuring of IgG2c isotype instead of IgG2a in immunized C57BL/6 mice with Plasmodium vivax TRAP as a subunit vaccine candidate in order to correct interpretation of Th1 versus Th2 immune response

September 5, 2020 - 15:36 -- NOT Open Access
Author(s): 
Nazeri S, Zakeri S, Mehrizi AA, Sardari S, Djadid ND
Reference: 
Exp Parasitol. 2020 Sep;216:107944

Evaluation of the murine isotype antibodies is essential in subunit vaccine development because inbred mouse strains with diverse genetic backgrounds respond different to recombinant proteins. In this regard, the main goal of this study was to measuring and comparing the profile of IgG isotype responses in C57BL/6 mice. For this purpose, the extracellular region of plasmodium vivax thrombospondin-related adhesive protein (PvTRAP) gene was expressed in Escherichia coli Rosetta (DE3)-pET23a.

Investigation of glucose-6-phosphate dehydrogenase (G6PD) deficiency prevalence in a Plasmodium vivax-endemic area in the Republic of Korea (ROK)

September 2, 2020 - 11:47 -- Open Access
Author(s): 
Wonsig Lee, Sang-Eun Lee, Min Jun Lee and Kyung Tae Noh
Reference: 
Malaria Journal 2020 19:317, 1 September 2020

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most prevalent inborn disorder. This X-chromosome-linked recessive disease affects more than 400 million people globally, and is associated with haemolytic anaemia after medication with the anti-latent malaria drug, primaquine. To prevent malaria, the Republic of Korea (ROK) Army administers malaria chemoprophylaxis. Due to the previously low G6PD deficiency prevalence in the ROK, prior to primaquine administration, testing for G6PD deficiency was not mandatory. In this study, to evaluate the risk from malaria chemoprophylaxis in the ROK, G6PD deficiency prevalence was investigated.

Not Open Access | Exposure to chloroquine in male adults and children aged 9-11 years with malaria due to Plasmodium vivax

August 25, 2020 - 15:26 -- NOT Open Access
Author(s): 
Ferreira Vieira MVD, Vieira JLF
Reference: 
Trans R Soc Trop Med Hyg. 2020 Aug 24:traa079

Chloroquine is effective against the asexual blood stage of Plasmodium vivax. A high proportion of children are underdosed with the drug, but there are no studies comparing chloroquine exposure in adults and children aged 8–11 years old. The present study intends to compare these populations using the area under the curve (AUC) derived from the plasma concentration-time profile in patients with P. vivax.

Recombinant Plasmodium vivax circumsporozoite surface protein allelic variants: antibody recognition by individuals from three communities in the Brazilian Amazon

August 24, 2020 - 15:18 -- Open Access
Author(s): 
Soares IF, López-Camacho C, Lima-Junior JDC, et al.
Reference: 
Sci Rep. 2020 Aug 20;10(1):14020

Circumsporozoite protein (CSP) variants of P. vivax, besides having variations in the protein repetitive portion, can differ from each other in aspects such as geographical distribution, intensity of transmission, vectorial competence and immune response. Such aspects must be considered to P. vivax vaccine development. Therefore, we evaluated the immunogenicity of novel recombinant proteins corresponding to each of the three P. vivax allelic variants (VK210, VK247 and P. vivax-like) and of the C-terminal region (shared by all PvCSP variants) in naturally malaria-exposed populations of Brazilian Amazon.

The biology of unconventional invasion of Duffy-negative reticulocytes by Plasmodium vivax and its implication in malaria epidemiology and public health

August 24, 2020 - 14:13 -- Open Access
Author(s): 
Lemu Golassa, Lucas Amenga-Etego, Eugenia Lo and Alfred Amambua-Ngwa
Reference: 
Malaria Journal 2020 19:299, 24 August 2020

Plasmodium vivax has been largely neglected over the past century, despite a widespread recognition of its burden across region where it is endemic. The parasite invades reticulocytes, employing the interaction between Plasmodium vivax Duffy binding protein (PvDBP) and human Duffy antigen receptor for chemokines (DARC). However, P. vivax has now been observed in Duffy-negative individuals, presenting a potentially serious public health problem as the majority of African populations are Duffy-negative.

Primaquine alternative dosing schedules for preventing malaria relapse in people with Plasmodium vivax

August 22, 2020 - 16:04 -- Open Access
Author(s): 
Rachael Milligan, André Daher, Gemma Villanueva, Hanna Bergman, Patricia M Graves
Reference: 
Cochrane Database of Systematic Reviews 2020, Issue 8. Art. No.: CD012656

Plasmodium vivax liver stages (hypnozoites) may cause relapses, prolonging morbidity, and impeding malaria control and elimination. The World Health Organization (WHO) recommends three schedules for primaquine: 0.25 mg/kg/day (standard), or 0.5 mg/kg/day (high standard) for 14 days, or 0.75 mg/kg once weekly for eight weeks, all of which can be difficult to complete. Since primaquine can cause haemolysis in individuals with glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, clinicians may be reluctant to prescribe primaquine without G6PD testing, and recommendations when G6PD status is unknown must be based on an assessment of the risks and benefits of prescribing primaquine. Alternative safe and efficacious regimens are needed.

Prevalence of CYP2D6 Genotypes and Predicted Phenotypes in a Cohort of Cambodians at High Risk for Infections with Plasmodium vivax

August 12, 2020 - 15:12 -- Open Access
Author(s): 
Spring MD, Lon C, Sok S, Sea D, Wojnarski M, Chann S, Kuntawunginn W, Kheang Heng T, Nou S, Arsanok M, Sriwichai S, Vanachayangkul P, Lin JT, Manning JE, Jongsakul K, Pichyangkul S, Satharath P, Smith PL, Dysoley L, Saunders DL, Waters NC
Reference: 
Am J Trop Med Hyg. 2020 Aug;103(2):756-759.

Clinical failure of primaquine (PQ) has been demonstrated in people with CYP450 2D6 genetic polymorphisms that result in reduced or no enzyme activity. The distribution of CYP2D6 genotypes and predicted phenotypes in the Cambodian population is not well described. Surveys in other Asian countries have shown an approximate 50% prevalence of the reduced activity CYP2D6 allele *10, which could translate into increased risk of PQ radical cure failure and repeated relapses, making interruption of transmission and malaria elimination difficult to achieve.

Polymorphism in the IL-1β promoter is associated with IgG antibody response to circumsporozoite protein repeats of Plasmodium vivax

August 10, 2020 - 15:58 -- Open Access
Author(s): 
Capobianco MP, Cassiano GC, Machado RLD, et al.
Reference: 
Trans R Soc Trop Med Hyg. 2020 Aug 7:traa055

It is well established that infection by Plasmodium vivax is a result of host-parasite interactions. In the present study, association with the IL1/IL2 cytokine profiles, anticircumsporozoite protein antibody levels and parasitic loads was evaluated in individuals naturally infected with P. vivax in an endemic area of the Brazilian Amazon.

Molecular surveillance for drug resistance markers in Plasmodium vivax isolates from symptomatic and asymptomatic infections at the China–Myanmar border

August 10, 2020 - 14:51 -- Open Access
Author(s): 
Yan Zhao, Lin Wang, Yaming Cao, et al.
Reference: 
Malaria Journal 2020 19:281, 5 August 2020

In the Greater Mekong sub-region, Plasmodium vivax has become the predominant species and imposes a major challenge for regional malaria elimination. This study aimed to investigate the variations in genes potentially related to drug resistance in P. vivax populations from the China–Myanmar border area. In addition, this study also wanted to determine whether divergence existed between parasite populations associated with asymptomatic and acute infections.

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