Plasmodium ovale malaria acquired in central Spain

Modelling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases

Malaria remains one of the most important infectious diseases globally due to its high incidence and mortality rates. The influx of infected cases from endemic to non-endemic malaria regions like Europe has resulted in a public health concern over sporadic local outbreaks. This is facilitated by the continued presence of competent Anopheles vectors in non-endemic countries.We modelled the potential distribution of the main malaria vector across Spain using the ensemble of eight modelling techniques based on environmental parameters and the Anopheles maculipennis s.l. presence/absence data collected from 2000 to 2020. We then combined this map with the number of imported malaria cases in each municipality to detect the geographic hot spots with a higher risk of local malaria transmission.The malaria vector occurred preferentially in irrigated lands characterized by warm climate conditions and moderate annual precipitation. Some areas surrounding irrigated lands in northern Spain (e.g. Zaragoza, Logroño), mainland areas (e.g. Madrid, Toledo) and in the South (e.g. Huelva), presented a significant likelihood of A. maculipennis s.l. occurrence, with a large overlap with the presence of imported cases of malaria.While the risk of malaria re-emergence in Spain is low, it is not evenly distributed throughout the country. The four recorded local cases of mosquito-borne transmission occurred in areas with a high overlap of imported cases and mosquito presence. Integrating mosquito distribution with human incidence cases provides an effective tool for the quantification of large-scale geographic variation in transmission risk and pinpointing priority areas for targeted surveillance and prevention.

Predicting the risk of malaria re-introduction in countries certified malaria-free: a systematic review

BACKGROUND

Predicting the risk of malaria in countries certified malaria-free is crucial for the prevention of re-introduction. This review aimed to identify and describe existing prediction models for malaria re-introduction risk in eliminated settings.

METHODS

A systematic literature search following the PRISMA guidelines was carried out. Studies that developed or validated a malaria risk prediction model in eliminated settings were included. At least two authors independently extracted data using a pre-defined checklist developed by experts in the field. The risk of bias was assessed using both the prediction model risk of bias assessment tool (PROBAST) and the adapted Newcastle-Ottawa Scale (aNOS).

RESULTS

A total 10,075 references were screened and 10 articles describing 11 malaria re-introduction risk prediction models in 6 countries certified malaria free. Three-fifths of the included prediction models were developed for the European region. Identified parameters predicting malaria re-introduction risk included environmental and meteorological, vectorial, population migration, and surveillance and response related factors. Substantial heterogeneity in predictors was observed among the models. All studies were rated at a high risk of bias by PROBAST, mostly because of a lack of internal and external validation of the models. Some studies were rated at a low risk of bias by the aNOS scale.

CONCLUSIONS

Malaria re-introduction risk remains substantial in many countries that have eliminated malaria. Multiple factors were identified which could predict malaria risk in eliminated settings. Although the population movement is well acknowledged as a risk factor associated with the malaria re-introduction risk in eliminated settings, it is not frequently incorporated in the risk prediction models. This review indicated that the proposed models were generally poorly validated. Therefore, future emphasis should be first placed on the validation of existing models.

Malaria Falciparum: Relapse After a Decade

Malaria is an infection caused by the Plasmodium malaria (PM) parasite. There are still cases of malaria that are reported in the United States on an annual basis. All these cases were a result of travelers who did not receive or follow their prescribed chemoprophylaxis, recommendations for avoiding mosquito bites while traveling, or relapsed dormant plasmodium. The malaria parasite can be transmitted by the bite of an infected female mosquito, through contact with infected blood products, or from mother to child during pregnancy through the placenta. It can take anywhere from 12 to 20 days for symptoms to appear, but there are cases of delayed development and/or relapse that can occur up to 13 years after the infection. We report a 31-year-old female with a history of malarial infection in Liberia, which had been treated ten years prior to her arrival in the United States. She presented to the hospital with abdominal pain, fever, and headache. She was eventually diagnosed with plasmodium malaria infection relapse and treated with a 14-day course of primaquine 300 mg daily, with the symptoms resolving a few days after. We believe her malarial infection was caused by a dormant malarial parasite that evaded the immune system and relapsed without having a risk factor for relapse or re-infection 10 years after her original infection.

Updated occurrence and bionomics of potential malaria vectors in Europe: a systematic review (2000-2021)

Despite the eradication of malaria across most European countries in the 1960s and 1970s, the anopheline vectors are still present. Most of the malaria cases that have been reported in Europe up to the present time have been infections acquired in endemic areas by travelers. However, the possibility of acquiring malaria by locally infected mosquitoes has been poorly investigated in Europe, despite autochthonous malaria cases having been occasionally reported in several European countries. Here we present an update on the occurrence of potential malaria vector species in Europe. Adopting a systematic review approach, we selected 288 papers published between 2000 and 2021 for inclusion in the review based on retrieval of accurate information on the following Anopheles species: An. atroparvus, An. hyrcanus sensu lato (s.l.), An. labranchiae, An. maculipennis sensu stricto (s.s.), An. messeae/daciae, An. sacharovi, An. superpictus and An. plumbeus. The distribution of these potential vector species across Europe is critically reviewed in relation to areas of major presence and principal bionomic features, including vector competence to Plasmodium. Additional information, such as geographical details, sampling approaches and species identification methods, are also reported. We compare the information on each species extracted from the most recent studies to comparable information reported from studies published in the early 2000s, with particular reference to the role of each species in malaria transmission before eradication. The picture that emerges from this review is that potential vector species are still widespread in Europe, with the largest diversity in the Mediterranean area, Italy in particular. Despite information on their vectorial capacity being fragmentary, the information retrieved suggests a re-definition of the relative importance of potential vector species, indicating An. hyrcanus s.l., An. labranchiae, An. plumbeus and An. sacharovi as potential vectors of higher importance, while An. messeae/daciae and An. maculipennis s.s. can be considered to be moderately important species. In contrast, An. atroparvus and An. superpictus should be considered as vectors of lower importance, particularly in relation to their low anthropophily. The presence of gaps in current knowledge of vectorial systems in Europe becomes evident in this review, not only in terms of vector competence but also in the definition of sampling approaches, highlighting the need for further research to adopt the appropriate surveillance system for each species.

Imported Malaria in Portugal: Prevalence of Polymorphisms in the Anti-Malarial Drug Resistance Genes pfmdr1 and pfk13

Malaria is one of the ‘big three’ killer infectious diseases, alongside tuberculosis and HIV. In non-endemic areas, malaria may occur in travelers who have recently been to or visited endemic regions. The number of imported malaria cases in Portugal has increased in recent years, mostly due to the close relationship with the community of Portuguese language countries. Samples were collected from malaria-infected patients attending Centro Hospitalar Lisboa Ocidental (CHLO) or the outpatient clinic of Instituto de Higiene e Medicina Tropical (IHMT-NOVA) between March 2014 and May 2021. Molecular characterization of Plasmodium falciparum pfk13 and pfmdr1 genes was performed. We analyzed 232 imported malaria cases. The majority (68.53%) of the patients came from Angola and only three patients travelled to a non-African country; one to Brazil and two to Indonesia. P. falciparum was diagnosed in 81.47% of the cases, P. malariae in 7.33%, P. ovale 6.47% and 1.72% carried P. vivax. No mutations were detected in pfk13. Regarding pfmdr1, the wild-type haplotype (N86/Y184/D1246) was also the most prevalent (64.71%) and N86/184F/D1246 was detected in 26.47% of the cases. The typical imported malaria case was middle-aged male, traveling from Angola, infected with P. falciparum carrying wild type pfmdr1 and pfk13. Our study highlights the need for constant surveillance of malaria parasites imported into Portugal as an important pillar of public health.

Identification of Three Distinct Groups of Anopheles lindesayi in Japan by Morphological and Genetic Analyses

Anopheles (Anopheles) lindesayi Giles consists of 5 subspecies. In Japan, only one subspecies, An. l. japonicus Yamada, has been reported. Its geographical populations are morphologically diverse; however, they are regarded as a single subspecies. In this study, we re-evaluated the taxonomic status of An. l. japonicus in Japan, and that of another subspecies, An. l. pleccau, distributed in Taiwan, by comparative morphological and molecular analyses based on the gene sequences of mitochondrial DNA cytochrome c oxidase I (COI) and ribosomal DNA internal transcribed spacer 2 (ITS2). Nucleotide sequence divergence was calculated using the Kimura-two-parameter (K2P) distance model. Phylogenetic trees based on COI and ITS2 sequences showed 3 distinct clades: Eastern Japan, Western Japan, and the Ryukyus. The sequences of the Ryukyu specimens were located within the same clade as that of the sequences of the Taiwanese specimens. Regarding the COI sequences, the 3 geographical groups in Japan were genetically distinct. The following morphological characteristics distinguished the groups: larval seta 1-S, pupal setae 5 through segments IV-VII, and pupal setae 6 on segments IV-VII. Based on these results, it was revealed that An. l. japonicus included 3 genetically and morphologically distinct groups: 2 groups of An. l. japonicus and a group in the Ryukyus, which was a synonym of An. l. pleccau.

Symptomatic Falciparum Malaria After Living in a Nonendemic Area for 10 Years: Recrudescence or Indigenous Transmission?

AbstractWe report the case of a patient from Mali who, after 10 years of living in Spain, presented with symptomatic Plasmodium falciparum malaria without having visited an endemic area during that time. We cannot completely rule out the possibility of indigenous transmission, but this case most likely represents recrudescence of an infection acquired over 10 years earlier.

Non-imported malaria in non-endemic countries: a review of cases in Spain

Spain declared the elimination of malaria in 1964. In non-endemic areas, the overwhelming majority of malaria cases are acquired abroad, and locally acquired infections are rare events. In Spain, malaria is a statutorily notifiable disease. During these fifty years more than ten thousand malaria cases have been reported, and about 0.8% of them did not have a history of recent travel. In this report, it was carried out a review of the ways in which malaria can be transmitted in non-endemic areas and a short description of the Spanish cases, aggregated by their transmission mechanisms. Four cases contracted malaria by mosquito bites; there were two autochthonous cases and two of "airport malaria". The other 28 cases were: congenital malaria cases, transfusion-transmitted malaria, post-transplant cases, nosocomial transmission and cases in intravenous drug users. In addition, in 1971 there was an outbreak of 54 cases due to exposure to blood or blood products. So, while malaria usually is an imported disease in non-endemic areas, it should not be excluded in the differential diagnosis of persons who have fever of unknown origin, regardless of their travel history.

Source identification of autochthonous-introduced Plasmodium vivax Malaria, Spain

In 2014, an autochthonous case of introduced malaria caused by Plasmodium vivax was identified in Spain. The strain that infected this patient was identical to that of a prior imported case from Pakistan. This is the first case where the source of infection could be identified since elimination in Spain.

Autochthonous Plasmodium vivax malaria in a Greek schoolgirl of the Attica region

In August 2009, one case of autochthonous malaria due to Plasmodium vivax was diagnosed in Greece in a young woman residing in the Eastern Attica region. The source of infection could not be identified. No other autochthonous malaria cases have been described in the Attica region since 1974. This was a sporadic case with no evidence of further local transmission, and no more cases have been reported in Attica up to now, two years later.

Imported malaria in an area in southern Madrid, 2005-2008

BACKGROUND

In Spain, malaria cases are mostly due to migrants and travellers returning from endemic areas. The objective of this work was to describe the malaria cases diagnosed at the Severo Ochoa University Hospital (HUSO) in Leganés in the south of the Madrid Region from 2005 to 2008.

METHODS

Descriptive retrospective study performed at HUSO. Data sources are registries from the Microbiology Department and malaria cases notified to the Preventive Medicine Department. Analysed parameters were: administrative, demographical, related to the stay at the endemic country, clinical, microbiological diagnosis method, pregnancy, treatment and prophylaxis, co-infections, and days of hospital stay.

RESULTS

Fifty-seven patients diagnosed with malaria were studied. Case distribution per year was 13 in 2005, 15 in 2006, 15 in 2007 and 14 in 2008. Thirty-three patients were female (57.9%) and 24 male (42.1%). Mean age was 27.8 years. Most of the malaria cases were acquired in Nigeria (49.1%) and Equatorial Guinea (32.7%). 29.1% of the patients were immigrants who had arrived recently, and 61.8% acquired malaria when travelling to their countries of origin to visit friends and relatives (VFR). Majority of cases were diagnosed between June and September. Microscopy was positive in 39 cases (68.4%) immunochromatography in 42 (73.7%) and PCR in the 55 cases where performed. Plasmodium falciparum was responsible for 94.7% of the cases. The more frequent symptoms were fever (77.2%), followed by headache and gastrointestinal symptoms (33.3%). Nine cases needed hospital admittance, a pregnant woman, three children, four VFR and an African tourist, but all evolved favourably. Chemoprophylaxis data was known from 55 patients. It was taken correctly in one case (1.8%), in five (9.1%) the prophylaxis was improper while the others 49 (89.1%) cases had not followed any anti-malarial prophylaxis.

CONCLUSIONS

Children, pregnant women and the VFR have the highest risk to present severe malaria and to need hospital admittance. Another important risk factor for acquiring malaria is incorrect prophylaxis. The first place for malaria acquisition was Nigeria and the main species causing malaria was P. falciparum.

Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain

BACKGROUND

International travel and immigration have been related with an increase of imported malaria cases. This fact and climate change, prolonging the period favouring vector development, require an analysis of the malaria transmission resurgence risk in areas of southern Europe. Such a study is made for the first time in Spain. The Ebro Delta historically endemic area was selected due to its rice field landscape, the presence of only one vector, Anopheles atroparvus, with densities similar to those it presented when malaria was present, in a situation which pronouncedly differs from already assessed potential resurgence areas in other Mediterranean countries, such as France and Italy, where many different Anopheles species coexist and a different vector species dominates.

METHODS

The transmission risk was assessed analysing: 1) climate diagrams including the minimum temperature for Plasmodium falciparum and Plasmodium vivax development; 2) monthly evolution of the Gradient Model Risk (GMR) index, specifying transmission risk period and number of potential Plasmodium generations; 3) ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI); 4) evaluation of A. atroparvus population dynamics.

RESULTS

Climatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for P. falciparum, and from May until October for P. vivax. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and A. atroparvus maximum abundance correspond to months with maximum growth of the rice fields.

CONCLUSIONS

The Ebro Delta presents the ecological characteristics that favour transmission. The temperature increase has favoured a widening of the monthly potential transmission window with respect to when malaria was endemic. The combined application of modified climate diagrams and GMR index, together with spatial characterization conforms a useful tool for assessing potential areas at risk of malaria resurgence. NDVI is a good marker when dealing with a rice field area.

[Could malaria and dengue reappear in Spain?]

The recent increase in immigration to Spain has facilitated the importation of many tropical diseases. Among these diseases, those of vectorial origin are among the most difficult to study. Some of the reasons for this difficulty are the complexity due to the variety of hosts involved in the transmission cycles and the need to know all the physiological, bioecological and biogeographic parameters related to the vector in order to infer the actual possibilities of the emergence or reemergence of these diseases. This article provides information on imported diseases of unquestionable epidemiological interest for the population in Spain due to the presence of several species of culicid mosquitoes (Diptera, Culicidae) capable of transmitting these diseases in our country. Parasitic diseases such as malaria, which was highly endemic in Spain until 50 years ago, and other arboviral infections such as dengue and yellow fever, are analyzed in these terms. Various aspects related to the health system, as well as the different ways of tackling these issues, are also discussed.

A 2-year entomological study of potential malaria vectors in central Italy

Europe was officially declared free from malaria in 1975; nevertheless, this disease remains a potential problem related to the presence of former vectors, belonging to the Anopheles maculipennis complex. Autochthonous-introduced malaria cases, recently reported in European countries, together with the predicted climatic and environmental changes, have increased the concern of health authorities over the possible resurgence of this disease in the Mediterranean Basin. In Italy, to study the distribution and bionomics of indigenous anopheline populations and to assess environmental parameters that could influence their dynamics, an entomological study was carried out in 2005-2006 in an at-risk study area. This model area is represented by the geographical region named the Maremma, a Tyrrhenian costal plain in Central Italy, where malaria was hyperendemic up to the 1950s. Fortnightly, entomological surveys (April-October) were carried out in four selected sites with different ecological features. Morphological and molecular characterization, blood meal identification, and parity rate assessment of the anophelines were performed. In total, 8274 mosquitoes were collected, 7691 of which were anophelines. Six Anopheles species were recorded, the most abundant of which were Anopheles labranchiae and An. maculipennis s.s. An. labranchiae is predominant in the coastal plain, where it is present in scattered foci. However, this species exhibits a wider than expected range: in fact it has been recorded, for the first time, inland where An. maculipennis s.s. is the most abundant species. Both species fed on a wide range of animal hosts, also showing a marked aggressiveness on humans, when available. Our findings demonstrated the high receptivity of the Maremma area, where the former malaria vector, An. labranchiae, occurs at different densities related to the kind of environment, climatic parameters, and anthropic activities.

[Imported infectious diseases in Spain]

In Spain, owing to the rise of international travels and immigration, the number of patients with imported infectious diseases has increased, many of them from tropical or subtropical areas. In parallel, there has been a multiplication in the number of scientific papers with Spanish authors about imported infections due to parasites, fungus, mycobacteriae, bacteriae or viruses. The risk for public health is low, althought for their correct prevention and control it is important to ease an universal access to healthcare and fair socioeconomic conditions, along with maintaining an updated clinical and epidemiological training of the health personnel. These nationwide measures must be supplemented with worldwide initiatives of global control of these infections.

Using remote sensing to map larval and adult populations of Anopheles hyrcanus (Diptera: Culicidae) a potential malaria vector in Southern France

Background

Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus (Diptera: Culicidae). In the context of recent climatic and landscape changes, the evaluation of the risk of emergence or re-emergence of such a major disease is of great importance in Europe. When assessing the risk of emergence of vector-borne diseases, it is crucial to be able to characterize the arthropod vector's spatial distribution. Given that remote sensing techniques can describe some of the environmental parameters which drive this distribution, satellite imagery or aerial photographs could be used for vector mapping.

Results

In this study, we propose a method to map larval and adult populations of An. hyrcanus based on environmental indices derived from high spatial resolution imagery. The analysis of the link between entomological field data on An. hyrcanus larvae and environmental indices (biotopes, distance to the nearest main productive breeding sites of this species i.e., rice fields) led to the definition of a larval index, defined as the probability of observing An. hyrcanus larvae in a given site at least once over a year. Independent accuracy assessments showed a good agreement between observed and predicted values (sensitivity and specificity of the logistic regression model being 0.76 and 0.78, respectively). An adult index was derived from the larval index by averaging the larval index within a buffer around the trap location. This index was highly correlated with observed adult abundance values (Pearson r = 0.97, p < 0.05). This allowed us to generate predictive maps of An. hyrcanus larval and adult populations from the landscape indices.

Conclusion

This work shows that it is possible to use high resolution satellite imagery to map malaria vector spatial distribution. It also confirms the potential of remote sensing to help target risk areas, and constitutes a first essential step in assessing the risk of re-emergence of malaria in southern France.

Paludismo importado en un hospital general de Madrid

INTRODUCTION

To study the clinical and epidemiological characteristics of malaria and the diagnosis of this condition in a general hospital that does not have a specialized tropical medicine unit.

METHODS

Retrospective study of all malaria cases diagnosed by thick film and/or PCR-positive status for any Plasmodium spp. from 1999 to 2003 in Hospital Príncipe de Asturias in Alcalá de Henares (Madrid, Spain).

RESULTS

Over the period studied, 89 cases of malaria were diagnosed. Most patients were African immigrants who had recently left their countries of origin (52%), or immigrants residing in Spain who had traveled to Africa for a short visit (35%) and did not take prophylaxis. The distribution of cases by species was Plasmodium falciparum 89%, P. ovale 7% and P. malariae 4%. Clinical data were non-specific and the percentage of severe complications was low (6.7%). A second-generation test for rapid detection of P. falciparum antigen (PfHRP2) was studied in a group of 46 patients with suspected malaria; the results obtained were similar to thick film as compared to PCR for diagnosing P. falciparum infection.

CONCLUSIONS

Access to information on prevention and chemoprophylaxis should be available to all travelers, particularly immigrants visiting their countries of origin. Most semi-immune patients with uncomplicated malaria can be treated on an outpatient basis. PfHRP2 antigen detection, a fast, reliable method for diagnosing malaria due to P. falciparum, can be used in addition to the thick film method in our setting.

Biology and dynamics of potential malaria vectors in Southern France

BACKGROUND

Malaria is a former endemic problem in the Camargue, South East France, an area from where very few recent data concerning Anopheles are available. A study was undertaken in 2005 to establish potential malaria vector biology and dynamics and evaluate the risk of malaria re-emergence.

METHODS

Mosquitoes were collected in two study areas, from March to October 2005, one week every two weeks, using light traps+CO2, horse bait traps, human bait catch, and by collecting females in resting sites.

RESULTS

Anopheles hyrcanus was the most abundant Anopheles species. Anopheles melanoon was less abundant, and Anopheles atroparvus and Anopheles algeriensis were rare. Anopheles hyrcanus and An. melanoon were present in summer, whereas An. atroparvus was present in autumn and winter. A large number of An. hyrcanus females was collected on humans, whereas almost exclusively animals attracted An. melanoon. Based on an enzyme-linked immunosorbent assay, almost 90% of An. melanoon blood meals analysed had been taken on horse or bovine. Anopheles hyrcanus and An. melanoon parity rates showed huge variations according to the date and the trapping method.

CONCLUSION

Anopheles hyrcanus seems to be the only Culicidae likely to play a role in malaria transmission in the Camargue, as it is abundant and anthropophilic.

RDNA sequences of Anopheles species from the Iberian Peninsula and an evaluation of the 18S rRNA gene as phylogenetic marker in anophelinae

The complete 18S rDNA and internal transcribed spacer (ITS)-2 rDNA sequences were obtained from Anopheles atroparvus Van Thiel and Anopheles plumbeus Stephens from two areas of Spain. The number of nucleotide differences in the 18S rDNA of the two species is high compared with differences in the same gene of other invertebrate vectors. In Anopheles, short 18S rDNA sequences are richer in AT than the longer sequences, which are richer in GC and include extremely GC-biased expanded regions. Four small regions in the variable regions V4 and V7 contain the majority of nucleotide differences. The results did not support the use of partial sequences for relationship analyses. Genetic distances and phylogenetic analyses supported the most recent classification of Anopheles. The complete 18S rDNA sequence is better for studying anopheline phylogenetics.

Drivers for the emergence and re-emergence of vector-borne protozoal and bacterial diseases

In recent years, vector-borne parasitic and bacterial diseases have emerged or re-emerged in many geographical regions causing global health and economic problems that involve humans, livestock, companion animals and wild life. The ecology and epidemiology of vector-borne diseases are affected by the interrelations between three major factors comprising the pathogen, the host (human, animal or vector) and the environment. Important drivers for the emergence and spread of vector-borne parasites include habitat changes, alterations in water storage and irrigation habits, atmospheric and climate changes, immunosuppression by HIV, pollution, development of insecticide and drug resistance, globalization and the significant increase in international trade, tourism and travel. War and civil unrest, and governmental or global management failure are also major contributors to the spread of infectious diseases. The improvement of epidemic understanding and planning together with the development of new diagnostic molecular techniques in the last few decades have allowed researchers to better diagnose and trace pathogens, their origin and routes of infection, and to develop preventive public health and intervention programs. Health care workers, physicians, veterinarians and biosecurity officers should play a key role in future prevention of vector-borne diseases. A coordinated global approach for the prevention of vector-borne diseases should be implemented by international organizations and governmental agencies in collaboration with research institutions.

Rapid diagnostic testing for malaria

Malaria rapid diagnostic devices (MRDD) have been developed with the hope that they would offer accurate, reliable, rapid, cheap and easily available alternatives to traditional methods of malaria diagnosis. The results from early malaria rapid diagnostic studies were quite promising, especially for detecting Plasmodium falciparum at densities of more than 100-500 parasites/microl. Despite the introduction of these devices over a decade ago, only a few target antigens have been introduced. Of greater concern, these devices have shown limitations in sensitivity, ability to differentiate species and robustness under field conditions in the tropics. Recent trials have revealed wide variability in sensitivity both within and between products. We review the recent trials assessing MRDD use for the diagnosis of P. falciparum and non-P. falciparum infections in endemic and non-endemic countries and describe the various aspects of these devices which need further improvement. High quality, accurate, rapid and affordable diagnostic tools are urgently needed now that new antimalarial regimens, characterized by higher cost and increased toxicity, have been introduced more widely in response to emerging multi-drug resistance.