Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmo- dium falciparum (Pf). Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high preva- lence of Duffy negativity provided a rationale for excluding the possibility of Plasmodiumvivax (Pv) transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified frame- work to reflect the strength of evidence of indigenous Pv transmissionin terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 coun- tries were attributed with infections of visiting travellers. Overall, moderate to conclusive evi- dence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection inAfricain 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low fre- quency of susceptible hosts found that reports of Pv prevalence were consistent with trans- mission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria par- asite across most of sub-Saharan Africa, the evidence presented here highlights its wide- spread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health significance of Pv, as well as the other neglected non- Pf parasites, which are currently invisible to most public health authorities inAfrica, but which can cause severe clinical illness and require specific control interventions.
Woreda (Halaba) and Hawasa town in Sidama Zone (Hawassa) (Fig 1). Details on the local population and malaria epidemiology in each of the districts are provided in the Supplemen- tary Material (S1 Table). Patients were enrolled to the study during the peak malaria transmis- sion season between May and November 2013. In Arbaminch, the majority of patients were enrolled within the framework of a P. vivax chloroquine sensitivity survey conducted at Shele Health Center. Additional patients were recruited by cross-sectional sampling from Arba- minch Hospital. In Badawacho and Halaba, patients were recruited in the framework of a P. vivax chloroquine survey conducted at Shone Health Center and Guba Health Center, respec- tively. In Hawassa, all patients were recruited by cross-sectional sampling at Adare Hospital and Millenium Health Center. Enrolment criteria were uncomplicated P. vivax mono-infection with microscopy-determined parasite density above 250 μl -1 , an axillary temperature of 37.5°C or history of fever within 48 hours of presentation, and residence in close proximity to the health center (i.e. within 10 km radius). Patients were asked to donate a capillary (50– 150 μl) blood sample spotted onto filter paper (Whatman 1 3MM filter paper, Cat
The epidemiological findings from the investigation indicated that the autochthonous transmission route occurred by means of the bite of a locally infected Anopheles spp mosquito. As the individuals of the cases did not have any history of traveling to endemic areas or other possible exposures relating to malaria transmission of malaria, the presence of prospectors who were positive for Plasmodiumvivax, along the Tejuco River, established a focus for the transmission. Imported cases of falciparum malaria were not encountered. However, one of the individuals of the imported cases reported that he had acquired mixed malaria in his region of origin (State of Pará), in December 2004 and that he had not undergone appropriate treatment. This suggests that a low parasitemia of gametocytes of Plasmodium falciparum may have persisted in this individual, at a level below the sensitivity of the thick blood smear test, for some weeks. This could explain the origin of the cases of malaria falciparum. On average, the ratio of gametocytes of Plasmodium falciparum to the asexual stages of the parasite is 1:156. The mean duration of circulation of these gametocytes is 6.4 days, although gametocytes with longevity of up to four weeks have been reported in the bloodstream 4 15 . The cases identified in
DISCUSSION: Malaria infects mankind globally. According to World Health Organization assessment, about 40% of the world population is at risk of developing malaria. About 300- 500 million people are infected with it. Every year about 2 million people die due to malaria and its complications. The highest mortality is inAfrica, mainly in young children.. Plasmodiumvivax is the most widely distributed human malaria parasite with an at risk population of 2.5 billion persons. Although the exact burden of disease caused by P. vivax infection is still a matter of debate, this parasite causes approximately 100–300 million clinical cases each year.. The trend of disease with plasmodiumvivax malaria is changing. It is increasingly recognized that serious and life threatening complications can occur with vivax malaria. 
The incidence of malaria in Brazil has increased dramatically in recent decades, from 52,000 cases recorded in 1970 to more than 630,000 cases in 1999. A major change has also been observed in the distribution of Plasmodium species over the last years: in the 1980s, P. falciparum and P. vivax were similarly prevalent, while in 1999 P. vivax was detected in more than 80% of malaria cases diagnosed microscopically in Brazil. P. malariae has been officially reported in less than 0.5% of malaria patients in the 1990s (National Health Foundation, unpublished data). Malar ia transmissionin Brazil occurs essentially in the Amazon Basin, where more than 99% of infections are acquired. Most affected subjects are migrants living in frontier agricultural settlements and mining areas 8 .
Malaria is still endemic in the Upper-Maroni area, despite of sanitary service commitments for many years. Disease control in the villages of Twenké, Taluène and Cayodé is actually based on curative treatment of sus- pected and confirmed cases and quarterly house spray- ing operations with deltamethrin insecticide. Attempts to control malaria transmitted by An. darlingi by spray- ing houses with residual insecticides have been unsuc- cessful in many areas for a combination of entomologi- cal, environmental and sociological reasons (Rozendaal et al. 1989, Roberts & Alecrim 1991). The main limiting factor for successful control in Amerindian villages is the difficulty of implementing a strategy adapted to the culture of the local populations. In the villages of Twen- ké, Taluène and Cayodé, construction practices probably contribute to the persistence of malaria. In the tradition- al Amerindian houses, residual insecticide house spray- ing is expected to be ineffective, due in part to repel- lency. Discontinuing insecticide spraying in houses and instead supporting the use of personal protection and, in particular, promoting the use of insecticide impreg- nated materials could improve malaria control in such a situation. Amerindian people in the villages of Twenké, Taluène and Cayodé use hammock nets which are gener- ally not impregnated with insecticides, allowing feed- ing of mosquitoes on people through the net during the night; in other cases, the nets have holes or are inade- quately tucked in around the edges. The protective effect would probably be greatly improved by net impregnation with a pyrethroid insecticide. Demonstrations of a reduc- tion in mosquito biting and resting densities in villages where all inhabitants sleep under impregnated nets are numerous in the literature. The use of impregnated nets, coupled with the use of repellents and the early treatment
Malaria is a world wide problem and it still remains as a concern in the Eastern Mediterranean region and in Iran (Sadrizadeh 1999, WHO 2003). Iran was divided into two malaria zones, North and South of the Zagros Range of Mountains (Manouchehri et al. 1992), including South- eastern (SE) and Northwestern (NW) provinces (Zakeri et al. 2004, Nahrevanian et al. 2006). The prevalent species is Plasmodiumvivax followed by Plasmodium falcipar- um (Zaim 1987, Edrissian 2002) and mixed-infections (Assmar et al. 2003). Out of 23,562 malaria cases have been reported in the country in 2003, more than 70% oc- curred in the SE part (Zakeri et al. 2002, WHO 2003). Recently, a new threat of imported malaria emerged from the NW part of the country, Parsabad area, which was affected by a serious epidemic of P. vivax (Sadrizadeh 1999). To date, the malaria situation in SE corner is seri- ous (Zakeri et al. 2002). However, in other endemic areas, malaria is hypoendemic with uncomplicated cases (Edris- sian et al. 1993). A malaria eradication programme began in Iran in 1949 and changed to malaria control in 1985 as a result of constraints and challenges. In the SE provinces, the major peak of malaria transmission occurs between September and November, with 21% of malaria cases in this region caused by P. falciparum (WHO 2004). Chlo- roquine (CQ) is still being recommended as the first-line treatment for uncomplicated cases of P. falciparum ma- laria, with a combination of sulfadoxine-pyrimethamine and quinine recommended for the CQ treatment failures.
In Honduras malaria transmission is seasonal and in 2010 there were 9,078 reported malaria cases. Plasmodiumvivax mono-infection accounted for 88% and 12% were due to Plasmodium falciparum mono-infection and mixed P. vivax and P. falciparum infections. The country is divided into 20 health regions and there are 1,743 health facilities . Samples were collected from patients that sought medical attention at the Hospital Escuela that is a teaching hospital in Distrito Central-Tegucigalpa, the regional hospitals in Trujillo, La Ceiba and Juticalpa, two primary health centres in Puerto Lempira and Iriona and one regional laboratory in Juticalpa. Samples were col- lected at Hospital Escuela between 2004 and 2006 and during 2009 at all other sites. The locations of all sites are shown in Figure 1. At the Hospital Escuela sample collec- tion was considered to be part of routine malaria surveil- lance and did not involve additional sampling or collection of patient data. At the other health facilities patients who sought medical attention and were diagnosed with malaria
Since Duffy negative individuals are largely refractory to P. vivax infection , high population frequencies of this phenotype have a dramatic suppressing effect on endemicity, even where conditions are otherwise well suited for transmission . The predominance of Duffy negativity inAfrica has led to a historical perception that P. vivax is absent from much of the continent, and a dearth of surveys or routine diagnoses testing for the parasite have served to entrench this mantra . However, evidence exists of autochthonous P. vivaxtransmission across the continent , and therefore we did not preclude any areas at risk a priori. Instead, we used a recent map of estimated Duffy negativity phenotypic frequency  and incorporated the potential influence of this blood group directly in the MBG modelling framework. The mapped Duffy-negative population fraction at each location was excluded from the denominator in PvPR survey data, such that any P. vivax positive individuals were considered to have arisen from the Duffy positive population subset. Thus in a location with 90% Duffy negativity, five positive individuals in a survey of 100 would give an assumed prevalence of 50% amongst Duffy positives. Correspondingly, prediction of PvPR was then restricted to the Duffy positive proportion at each pixel, with the final prevalence estimate re-converted to relate to the total population. This approach has two key advantages. First, predicted PvPR at each location could never exceed the Duffy positive proportion, therefore ensuring biological consistency between the P. vivax and Duffy negativity maps. Second, where PvPR survey data were sparse across much of Africa, the predictions could effectively borrow strength from the Duffy negativity map because predic- tions of PvPR were restricted to a much narrower range of possible values.
The relapse patterns and variations in the length of the incubation period, including a delay of four months or longer, was first described by Korteweg in Holland between 1901 and 1902 (cited by Swellengrebel and De Buck ). Later, in 1935, Nikolaev proposed that there were two strains of P. vivax (cited by Tiburskaya ) with different incubation periods and gave the sub-spe- cific taxonomic name of P. vivax hibernans to the vari- ety with the longest incubation period. It was suggested that this sub-species had adapted to more northern lati- tudes where the anopheles vector was absent for much of the year. Shute (1946)  proposed that the sporo- zoite infective inoculum would be inversely related to the prepatent and incubation period. However, in Mos- cow, Tiburskaya  demonstrated situations in which the length of the incubation period did not depend on the number of inoculated sporozoites, but instead was determined by the inherent properties of the strains. It was also believed that strains with prolonged latency could be attributed either to the “senility” of the sporo- zoite towards the end of the season or to the low num- ber of sporozoites in the infective bite .
A plausible explanation for the low immunogenicity of PvDBP is the fact that this protein is localised in the micronemes until the beginning of the process of eryth- rocyte invasion by merozoites (Adams et al. 1990). As a consequence of its brief exposure, the host immune system seems to have little opportunity to produces an efficient antibody response. However, the “just-in-time” hypothesis of PvDBP exposure (Singh et al. 2006) does not completely explain the large proportion of individu- als who remain unresponsive to PvDBP after prolonged exposure to malaria. The reasons for this are not clear, but may relate to the complexity of the immune response, in terms of genetic diversity of both the parasite and hu- man populations. With regard to the genetic diversity of the parasite, several studies now indicate the existence of strain-specificity in the natural immune response against PvDBP (Ceravolo et al. 2009, Cole-Tobian et al. 2009, Chootong et al. 2012). In a study conducted dur- ing a malaria outbreak outside of the Brazilian endemic area, we demonstrated that the majority of responders had developed inhibitory antibodies against the homolo- gous DBPII sequence identified in the outbreak isolate (Ceravolo et al. 2009). These findings provided the first clear evidence that naturally-acquired inhibitory anti- bodies to DBPII are biased towards a specific allele in individuals with no previous exposure to malaria infec- tion (Ceravolo et al. 2009). In Thailand, an area of low unstable transmission of P. vivax, the inhibitory anti- body responses against DBPII also correlated with ho- mologous protection (Chootong et al. 2012). Similarly, a profile of strain-specific inhibitory activity was fre- quently observed among asymptomatic children from PNG (Cole-Tobian et al. 2009).
Nucleotide sequence analyses of the Pvs48/45 and Pvs47 genes were conducted in 46 malaria patients from the Republic of Korea (ROK) (n = 40) and returning travellers from India (n = 3) and Indonesia (n = 3). The domain structures, which were based on cysteine residue position and secondary protein structure, were similar between Plasmodiumvivax (Pvs48/45 and Pvs47) and Plasmodium falciparum (Pfs48/45 and Pfs47). In comparison to the Sal-1 reference strain (Pvs48/45, PVX_083235 and Pvs47, PVX_083240), Korean isolates revealed seven polymor- phisms (E35K, H211N, K250N, D335Y, A376T, I380T and K418R) in Pvs48/45. These isolates could be divided into five haplotypes with the two major types having frequencies of 47.5% and 20%, respectivelfy. In Pvs47, 10 poly- morphisms (F22L, F24L, K27E, D31N, V230I, M233I, E240D, I262T, I273M and A373V) were found and they could be divided into four haplotypes with one major type having a frequency of 75%. The Pvs48/45 isolates from India showed a unique amino acid substitution site (K26R). Compared to the Sal-1 and ROK isolates, the Pvs47 isolates from travellers returning from India and Indonesia had amino acid substitutions (S57T and I262K). The current data may contribute to the development of the malaria transmission-blocking vaccine in future clinical trials.
Figura 4. Índices populacionais de imunidade à malária por P. falciparum. Dados representativos de uma série de estudos em Kilifi, no Quênia. O padrão de idade e prevalência parasitária tanto malária clínica grave como em infecções assintomáticas. (Adaptado de Marsh & Kinyanjui, 2006). ............................................................................. 26 Figura 5. Resposta imune na malária: A célula dendrítica (CD) processa e apresenta epitopos do parasito. A produção de IL-12 pela CD ativa células NK, que produzem IFN- e induzem a diferenciação de linfócito T CD4 + . A expansão clonal dos linfócitos específicos induz a ativação de NK, CD e macrófagos, amplificando a resposta imune adaptativa. Os macrófagos secretam NO e TNF. A ativação de linfócitos B específicos estimula a produção de anticorpos IgG. A regulação negativa da resposta imune inata e adaptativa envolve a participação das citocinas IL-10 e TGF- . (Adaptado de STEVENSON & RILEY, 2004.) 27 Figura 6. Mapa do Brasil evidenciando a localização da região de estudo no estado do Amazonas. ............................................................................................................................. 39 Figura 7. Estratégias de análise para fenotipagem celular. Células previamente presentes em gate de linfócitos (distribuição pontual de forward scatter x side scatter) foram analisadas em relação a sua fluorescência tipo I (CD4 FITC) e tipo III (CD45RO PE-Cy5). A frequência de linfócitos duplo positivos (CD4 + CD45RO + , gate retangular) que expressam CCR7 (A) ou CD62L (B) foram determinados por citometria de fluxo. ..................................................... 42 Figura 8. Perfil fenotípico da expressão de IFN- e IL-10 em células T CD4 + em malária- naïve e pacientes infectados por P. vivax. Resultados foram expressos em números absolutos (células/mm 3 ) de células T CD4 + expressando (A) IFN- e (B) IL-10. ............................... 46 Figura 9. Análise de células T CD4 + naïve e de memória por citometria de fluxo. Resultados expressos em número absoluto (células/mm 3 ) de (A) CD4 + CD45RA + e (B) CD4 + CD45RO high de indivíduos negativos e infectados por P. vivax ................................... 47 Figura 10. Expressão de citocinas IFN- e IL-10 por células T CD 4 +
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Neste volume, Novaretti e colaboradores apresentam uma revisão sobre o sistema de grupos sangüíneos Duffy. Os autores discutem os aspectos estruturais da proteína FY e mostram resultados recentes obtidos por análise molecular dos genes funcionais e silenciosos do locus FY. Traçam o perfil dos anticorpos desse sistema e comentam sua impor- tância na medicina transfusional e na doença hemolítica perinatal. Além disso, abordam o papel dos antígenos Duffy, também denominados DARC (Duffy Antigen/Receptor for Chemokines), como receptores para o Plasmodiumvivax e para a interleucina 8, dando destaque ao papel biológico re- sultante da expressão desse sistema em outros tecidos.
In Iran, both Plasmodiumvivax and P. falciparum malaria have been detected, but P. vivax is the predominant species. Point mutations in dihydrofolate reductase (dhfr) gene in both Plasmodia are the major mechanisms of pyrimethamine resistance. From April 2007 to June 2009, a total of 134 blood samples in two endemic areas of southern Iran were collected from patients infected with P. vivax and P. falciparum. The isolates were analyzed for P. vivax dihydrofolate reductase (pvdhfr) and P. falciparum dihydrofolate reductase (pfdhfr) point mutations using various PCR-based methods. The majority of the isolates (72.9%) had wild type amino acids at five codons of pvdhfr. Amongst mutant isolates, the most common pvdhfr alleles were double mutant in 58 and 117 amino acids (58R-117N). Triple mutation in 57, 58, and 117 amino acids (57L/58R/117N) was identified for the first time in the pvdhfr gene of Iranian P. vivax isolates. All the P. falciparum samples analyzed (n = 16) possessed a double mutant pfdhfr allele (59R/108N) and retained a wild-type mutation at position 51. This may be attributed to the fact that the falciparum malaria patients were treated using sulfadoxine–pyrimethamine (SP) in Iran. The presence of mutant haplotypes in P. vivax is worrying, but has not yet reached an alarming threshold regarding drugs such as SP. The results of this study reinforce the importance of performing a molecular surveillance by means of a continuous chemoresistance assessment.
O artesunato demostrou ser droga mais veloz que a cloroquina tanto na negativação da parasitemia assexuada, quanto na cura clínica, indicando ser uma excelente opção em casos especiais de impossibilidade do uso de cloroquina, corroborando os resultados de outros estudos feitos com esta droga no tratamento de malária vivax 2 7 12 .
3 glicoproteína homodimérica secretada por células Th1, células natural killer (NK) e linfócitos TCD8 + (Lammas et al, 2000). Possui potente efeito imunomodulador em diferentes células do sistema imunológico in vivo e in vitro (Young e Hardy, 1995; Billiau, 1996). Outros estudos com P. vivax têm avaliado o nível de citocinas séricas no soro de indíduos infectados (Andrade et al, 2010; Gonçalves et al, 2010). O TGF- em alguns estudos mostrou ser importante nas respostas inflamatórias associadas com a patologia das formas infectantes por P. falciparum (Noone et al, 2013). Tanto na malária humana quanto na murina, pouco se conhece sobre as ações do TGF- , porém sua capacidade de estimular a produção de quimiocinas importantes para o recrutamento de neutrófilos e linfócitos T CD8 + para o tecido, a faz um importante alvo de estudo, já que estas células parecem estar envolvidas na suscetibilidade e resistência à forma cerebral (Campanella et al, 2008; Miu et al, 2008). Estudos realizados em pacientes infectados por P. vivax, apresentaram aumento da expressão da célula produtora de IL-17 (Bueno et al, 2012). As células Th17 também podem estar envolvidas na resposta de defesa para infecção por bactérias, fungos e protozoários (Matsuzaki & Umemura, 2007). No entanto, o papel da citocina IL-17 nos mecanismos reológicos em processos infecciosos de indivíduos infectados com P. vivax constituem um campo aberto para novos estudos.
126.96.36.199.Nycodenz method. After sacrificing one mouse per each parasite line, heparinized syringes were used to subtract the blood from each mouse by cardiac puncture. PBS was added up to a volume of 2mL. Purified gametocytes were obtained by loading the blood on a 5mL of 49% Nycodenz solution in PBS, followed by a centrifugation of 20 minutes at 450 rcf room temperature (RT) with acceleration 3 but no brake. The brownish layer was collected from the gradient and centrifuged for 5 minutes at 450 rcf at RT. The supernatant was discarded. The purified gametocytes obtained were washed two times in ice-cold “enriched” PBS with spins of 5 minutes each at 450rct at 4ºC. Lysis of the parasites was done with 210 μl of NET-2++ buffer for 30 minutes at 4°C using a shaker. After lysis the extract was centrifuged for 10 minutes at 14000 rpm and the supernatant collected. 50 μl extract were used per IP with mouse anti-GFP-antibody (1µg Roche Diagnostics, Inc.), anti-c-myc- antibody (1 μg, Sigma-Aldrich, St. Louis Missouri, USA) or beads-only and incubated for 1 hour at 4°C using a shaker. Another 50µL were saved for the control input sample. Protein G Sepharose™ 4 Fast Flow beads (GE Healthcare), 20μL packed bead volume per IP, previously washed 5x with NET-2 buffer and 2x with NET-2++ buffer were then added to each sample and incubated for 1 hour and 30 minute at 4°C in a shaker. IP samples were afterwards washed three times with 200μL NET-2 buffer with an additional final wash with 300µL NET-2 buffer. One third of the final wash was resuspended in 500µL TRIzol® (Reagent for RNA from Ambion®), while the other two thirds were centrifuged and the beads resuspended in 50µL 2X SDS-PAGE loading buffer and used for western blot analysis.
Plasmodiumvivax é o parasita causador de malária humana com maior distribuição global, responsável pela redução da qualidade de vida de milhões de pessoas ao redor do mundo. O objetivo geral do trabalho foi contribuir, através de metodologias estatísticas e de bioinformática, para o entendimento do mecanismo de escape da eliminação pelo baço do hospedeiro utilizado por P. vivax. Para isso, primeiramente realizou-se a análise estatística de um experimento de transcritômica, através de microarrays. Esse experimento foi conduzido previamente pelo grupo de colaboradores do presente estudo, utilizando um modelo animal, Aotus lemurinus griseimembra, com o objetivo de identificar genes de P. vivax expressos somente em parasitas retirados de macacos que possuíam o baço intacto. Em uma segunda fase, foi projetado um tiling array contendo todos os éxons e as regiões 5’UTR e 3’UTR disponíveis do genoma de P. vivax, que será utilizado para a realização de mais investigações a respeito da influência da presença do baço na expressão gênica de P. vivax. Na última etapa, foi conduzida uma melhoria na anotação funcional do genoma de P. vivax, através de uma metodologia automática, com o objetivo de adicionar informações para auxiliar na interpretação biológica dos resultados obtidos anteriormente e em estudos futuros.