Ana Paula Arez

Ana Paula Arez
Institute of Hygiene and Tropical Medicine | IHMT · Medical Parasitology

PhD (w/ Habilitation)

About

62
Publications
7,972
Reads
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1,661
Citations
Citations since 2017
13 Research Items
642 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Introduction
Principal Investigator at IHMT Lisbon. Main research areas 1) Host susceptibility to disease [i) Erythrocyte enzyme deficiencies, association with malaria – population, proteomic and metabolomic studies; ii) Evaluation of 2,3-DPG toxicity and P. falciparum susceptibility], 2) Characterization and transmission dynamics of parasite populations [Factors affecting dynamics of Plasmodium concomitant infections in a malaria endemic area – Equatorial Guinea: analysis through a new modelling approach].
Additional affiliations
January 2008 - present
Universidade NOVA de Lisboa
Position
  • Instituto de Higiene e Medicina Tropical
January 2001 - present
Universidade NOVA de Lisboa
November 2000 - present
Institute of Hygiene and Tropical Medicine
Position
  • Principal Investigator

Publications

Publications (62)
Article
Full-text available
Extensive research has examined why some people have frequent Plasmodium falciparum malaria episodes in sub-Saharan Africa while others remain free of disease most of the time. In contrast, malaria risk heterogeneity remains little studied in regions where P. vivax is the dominant species. Are repeatedly infected people in vivax malaria settings su...
Article
Full-text available
Malaria remains a major world public health problem, contributing to poverty and inequality. It is urgent to find new efficacious tools with few adverse effects. Malaria has selected red blood cell (RBC) alterations linked to resistance against infection, and understanding the protective mechanisms involved may be useful for developing host-directe...
Article
Full-text available
Over the past two decades, a considerable expansion of malaria interventions has occurred at the national level in Angola, together with cross-border initiatives and regional efforts in southern Africa. Currently, Angola aims to consolidate malaria control and to accelerate the transition from control to pre-elimination, along with other country me...
Article
Full-text available
Background Sickle Cell Anemia (SCA) is a genetic disease caused by the c.20 A > T mutation in HBB gene, generally characterized by sickle erythrocytes, chronic hemolytic anemia, and vaso-occlusive events. This study aimed to investigate genetic modulators of anemia severity, chronic hemolytic rate, and clinical manifestations in pediatric SCA patie...
Article
Full-text available
Mechanisms of malaria parasite interaction with its host red blood cell may provide potential targets for new antimalarial approaches. Pyruvate kinase deficiency has been associated with resistance to malaria in both experimental models and population studies. Two of the major pyruvate kinase deficient-cell disorders are the decrease in ATP and the...
Article
Full-text available
In the south and southeast regions of Brazil, cases of malaria occur outside the endemic Amazon region near the Atlantic Forest in some coastal states, where Plasmodium vivax is the recognized parasite. Characteristics of cases and vectors, especially Anopheles (Kerteszia) cruzii, raise the hypothesis of a zoonosis with simians as reservoirs. The p...
Preprint
Full-text available
Introduction The residual malaria of Atlantic Forest systems in Brazil occurs as an endemic disease with low frequency of cases. The chronological and spatial distance among the cases indicate an absence of fitness to the classical malaria cycle. This peculiar condition raised the suspicion of a reservoir, possibly the non-human primates. Simian an...
Article
Full-text available
The aim of this study was to explore the association between alpha-thalassemia, fetal hemoglobin, hematological indices, and clinical adverse events in Angolan sickle cell disease pediatric patients. A total of 200 sickle cell disease (SCD) children were sampled in Luanda and Caxito. A venous blood sample was collected and used for hematological an...
Article
Full-text available
Plasmodium ovale curtisi and Plasmodium ovale wallikeri are two sympatric human malaria species prevalent in Africa, Asia and Oceania. The reported prevalence of both P. ovale spp. was relatively low compared to other malaria species, but more sensitive molecular detection techniques have shown that asymptomatic low-density infections are more comm...
Article
Full-text available
Background: After the introduction of an artemisinin-based combination therapy, the reduction of prevalence of malaria infections has shown a remarkable progress during the last decade. However due to the lack of a consistent malaria control programme and socioeconomic inequalities, Plasmodium infection is still one of the major cause of disease i...
Poster
Full-text available
MOLECULAR EVIDENCE OF POSITIVE SELECTION IN TRANSGLUTAMINASES OF ANOPHELES GAMBIAE Faleiro B. D.1, Mendes C.1, Custódio A.1, Pinto J.1,2, Arez A. P.1,2, Salgueiro P.1,2, Silveira H.1,2 1 Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical. Universidad Nova de Lisboa. Lisbon, Portugal. 2 GHTM –VBD group. Instituto de Higiene e...
Article
Full-text available
The efforts to control malaria may affect malaria parasite genetic variability and drug resistance, the latter associated with genetic events that promote mechanisms to escape drug action. The worldwide spread of drug resistance has been a major obstacle in controlling Plasmodium falciparum malaria, thus the study of the origin and spread of associ...
Article
Full-text available
Background: Clarifying the role of the innate immune system of the malaria vector Anopheles gambiae is a potential way to block the development of the Plasmodium parasites. Pathogen recognition is the first step of innate immune response, where pattern recognition proteins like GNBPs play a central role. Results: We analysed 70 sequences of the...
Conference Paper
Full-text available
A resistência de Plasmodium falciparum à maioria dos antimaláricos em uso é um dos maiores obstáculos ao controlo eficaz da malária. Fenómenos de resistência parasitária à terapia combinada na administração de artemisininas (ACT) foram relatados recentemente no Sudoeste Asiático, comprometendo os programas de controlo e eliminação da malária em tod...
Article
Full-text available
We report the presence of SNPs in Plasmodium falciparum K13-propeller gene in two African countries, Angola and Mozambique, where malaria is a serious public health problem. Samples were collected before and after ACT introduction as first-line treatment. In each country 50 samples collected before and 50 after ACT introduction were analysed. A tot...
Article
Full-text available
Background: In Plasmodium, the high level of genetic diversity and the interactions established by co-infecting parasite populations within the same host may be a source of selection on pathogen virulence and drug resistance. As different patterns have already been described in humans and mosquitoes, parasite diversity and population structure sho...
Data
Full-text available
Objective To investigate malaria prevalence and socio-economic conditions in East Timor. Methods Blood samples were collected from 650 individuals distributed among six districts in East Timor. 434 and 216 individuals were sampled by passive and active case detection, respectively (PCD, ACD). Results The results showed that the plasmodium infecti...
Data
Background: In response to chloroquine (CQ) resistance, the policy for the first-line treatment of uncomplicated malaria in the Democratic Republic of East Timor (DRET) was changed in early 2000. The combination of sulphadoxine-pyrimethamine (SP) was then introduced for the treatment of uncomplicated falciparum malaria.
Article
Full-text available
Background Pyruvate kinase (PK) deficiency, causing hemolytic anemia, has been associated to malaria protection and its prevalence in sub-Saharan Africa is not known so far. This work shows the results of a study undertaken to determine PK deficiency occurrence in some sub-Saharan African countries, as well as finding a prevalent PK variant underl...
Data
List of primers and annealing temperatures (a.t.) used in the amplification of PKLR promoter (Prom) and coding regions by PCR. (DOCX)
Data
Primers used for mitochondrial genome sequencing. (DOCX)
Data
Outgroup weights for haplotypes (>0.01). (DOCX)
Article
Full-text available
Plasmodium vivax, the second most prevalent of the human malaria parasites, is estimated to affect 75 million people annually. It is very rare, however, in west and central Africa, due to the high prevalence of the Duffy negative phenotype in the human population. Due to its rarity in Africa, previous studies on the phylogeny of world-wide P. vivax...
Article
Full-text available
Plasmodium vivax shows a small prevalence in West and Central Africa due to the high prevalence of Duffy negative people. However, Duffy negative individuals infected with P. vivax have been reported in areas of high prevalence of Duffy positive people who may serve as supply of P. vivax strains able to invade Duffy negative erythrocytes. We invest...
Article
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Ferroportin is a transmembrane protein responsible for iron export from enterocytes and macrophages. Mutation c.744G → T (Q248H), located in exon 6 of the ferroportin gene SLC40A1, is found as a polymorphism in populations of African origin. This mutation has been extensively analysed in African-Americans, but poorly studied in native African popul...
Article
To evaluate the risk of transmission of vector-borne diseases, regular updates of the geographic distribution of insect vectors are required. In the archipelago of Cape Verde, nine mosquito species have been reported. Of these, four are major vectors of diseases that have been present in the archipelago: yellow fever, lymphatic filariasis, malaria...
Article
The understanding of the complex life cycle of malaria has greatly improved in the last few years, however, despite decades of research and struggle against the disease, it continues to be a major public health problem, especially in the poorest areas of the world. Due to its long-term high prevalence in certain regions of the globe, malaria has ex...
Conference Paper
Full-text available
São Tome and Principe (STP) is a small nation – archipelago in West Africa where the trend of malaria prevalence has been changing back and forth, in the last decades: from an unattempted near eradication in the early 80s, to meso-hyperendemic levels in the 90s, back to pre-elimination in present times. It is of utmost importance to evaluate the ef...
Conference Paper
São Tomé e Príncipe (STP) é um arquipélago no Golfo da Guiné onde a tendência da prevalência de malária tem sido muito irregular nas últimas décadas, com a tentativa de erradicação no início dos anos 80, para níveis meso-hiperendémicos durante a década de 90, de volta a um cenário de pré-eliminação na actualidade. É de extrema importância avaliar o...
Article
Full-text available
In the Democratic Republic of East Timor, Plasmodium falciparum and Plasmodium vivax malaria coexist, but limited information is available about the latter species. Consequently, the prevalence of P. vivax and of its corresponding antifolate resistance-associated mutations in the pvdhfr and pvdhps genes was assessed here. Blood samples were collect...
Article
The genetic component of susceptibility to malaria is both complex and multigenic and the better-known protective polymorphisms are those involving erythrocyte-specific structural proteins and enzymes. In vivo and in vitro data have suggested that pyruvate kinase deficiency, which causes a nonspherocytic haemolytic anaemia, could be protective agai...
Article
Full-text available
Malaria in humans is caused by apicomplexan parasites belonging to 5 species of the genus Plasmodium. Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease is not known. Dimorphism in defined genes has led to P. ovale parasites being divided into classic and variant types. We hypothesiz...
Article
Malaria has occurred in the Cabo Verde archipelago with epidemic characteristics since its colonization. Nowadays, it occurs in Santiago Island alone and though prophylaxis is not recommended by the World Health Organization, studies have highlight the prospect of malaria becoming a serious public health problem as a result of the presence of antim...
Article
Full-text available
In response to chloroquine (CQ) resistance, the policy for the first-line treatment of uncomplicated malaria in the Democratic Republic of East Timor (DRET) was changed in early 2000. The combination of sulphadoxine-pyrimethamine (SP) was then introduced for the treatment of uncomplicated falciparum malaria. Blood samples were collected in two diff...
Article
Population samples from Angola, Mozambique, and S. Tomé e Príncipe were screened for the TPI gene promoter variants -5A-->G, -8G-->A and -24T-->G. Three haplotypes were identified in the three populations: the haplotype -5A-8G-24T (average frequency 65.3%) and two less common haplotypes -5G-8G-24T (average frequency 24.7%) and -5G-8A-24T (average f...
Article
Full-text available
In the malaria vector Anopheles gambiae Giles sensu stricto, two molecular forms denoted M and S are considered units of incipient speciation within this species. Very low hybrid frequencies and significant genetic differentiation have been found in sympatric M- and S-form populations. We studied the molecular form composition and the degree of gen...
Article
Malaria is one of the main human public health problems in the tropical world and is possibly becoming an emerging disease too in regions where it has been controlled. It has been an excellent model in the area of molecular studies, with scientific validation of techniques, application of data mainly in studies of parasite diversity and information...
Article
Full-text available
Plasmodium malariae, the parasite responsible for quartan malaria, is transmitted in most areas of malaria endemicity and is associated with significant morbidity. The sequence of the gene coding for the enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) was obtained from field isolates of P. malariae and from the closely related simian...
Conference Paper
Objectives: We have characterised the genetic diversity of Plasmodium falciparum populations in São Tomé and Príncipe islands (STP), West Africa, in order to assess patterns of population substructure and to relate these with epidemiological and control aspects of malaria. Methods: Blood samples were collected from 3 localities of São Tomé and 1 f...
Article
Full-text available
Malaria has come near eradication at archipelago of Cabo Verde in 1970. Infections are now only observed in Santiago, where outbreaks occur. In these islands, malaria is considered by the international community as being of limited risk and, therefore, no prophylaxis is recommended. Since the understanding of factors that determine malaria outbreak...
Article
Full-text available
We compared the distribution patterns of individual Plasmodium species and mixed-species infections in two geographically close endemic areas, but showing environmental differences. Comparisons concerned circulating Plasmodium infections in both human and mosquito vector populations in the dry and wet seasons, at a micro-epidemiological level (hous...
Article
Full-text available
An entomological study on vectors of malaria and their relative contribution to Plasmodium falciparum transmission in the semi-urban area of Ifakara, south-eastern Tanzania, was conducted. A total of 32 houses were randomly sampled from the area and light trap catches (LTC) performed in one room in each house every 2 weeks for 1 year. A total of 14...
Article
Clinical treatment failures of the hydroxynaphthoquinone atovaquone or its combination with proguanil (Malarone) in Plasmodium falciparum malaria has been recently documented. These events have been associated to single nucleotide polymorphisms (SNPs) in the parasite cytochrome b gene (cytb). In this report we describe a set of nest PCR-RFLP method...
Article
Full-text available
We studied malaria transmission by comparing parasite populations in humans and mosquito vectors at the household level. Blood samples were collected from all inhabitants for microscopic detection of gametocytes and polymerase chain reaction analysis. The next morning, blood-fed resting mosquitoes were collected inside the bed nets used by the indi...
Article
Genetic diversity of malaria parasites represents a major issue in understanding several aspects of malaria infection and disease. Genotyping of Plasmodium falciparum infections with polymerase chain reaction (PCR)-based methods has therefore been introduced in epidemiological studies. Polymorphic regions of the msp1, msp2 and glurp genes are the m...
Article
Arez, A. P., Lopes, D., Pinto, J., Franco, A. S., Snounou, G., and do Rosário, V. E. 2000. Plasmodium sp.: Optimal protocols for PCR detection of low parasite numbers from mosquito (Anopheles sp.) samples. Experimental Parasitology94, 269–272.
Article
Full-text available
We present the first parasitological, molecular and longitudinal analysis of an isolated outbreak of malaria. This outbreak occurred on Santiago Island (Republic of Cabo Verde), a region where malaria is hypoendemic and controlled, and thus the population is considered non-immune. Blood samples were collected from the inhabitants over 1 month and d...
Article
Full-text available
Polymerase chain reaction (PCR) is now widely used in malaria research for analysis of field samples. However, little has been reported regarding loss of sensitivity due to field methodology. Therefore, studies were carried out in relation to blood sampling (anticoagulants, culture medium, filter paper), storage (temperature, time and immediate lys...
Article
Full-text available
Tests for antibodies against CSP-protein by ELISA were used to assess mosquito mediated malaria transmission in the village of Achada Leite on the archipelago of Cabo Verde, an area with very low mosquito densities where a clonal Plasmodium falciparum outbreak occurred in October 1995. Anti-CSP antibodies were found among individuals who had previo...
Article
Full-text available
Parasites present in blood samples of asymptomatic carriers and in the midgut of mosquitoes collected within a few days from the same households, have been analysed by PCR. A high prevalence (32%) of infected mosquitoes was observed and, in half of these, two parasite species were found simultaneously. The distribution of parasite species in the mo...

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