Malaria in a Liver Transplant Recipient: A Case Report

Malaria is an exotic complication in liver transplants patients. It can be acquired either by transfusion of blood products or through the transplanted organ. Infections caused by Plasmodium spp are unusual in liver transplants; to date, only four cases have been reported in the literature. Herein we have presented a case of Plasmodium vivax in a liver transplant patient. This diagnosis must be excluded in febrile transplant patients in endemic areas, especially during the first 2 months. An epidemiological history relevant for malaria both in the donor and in the recipient must be routinely included with screening tests.

[Plasmodium vivax malaria with clinical presentation mimicking acute type idiopathic thrombocytopenic purpura]

Causes of thrombocytopenia are diverse, and infection with plasmodia often brings about thrombocytopenia. Japan is not an endemic area of malaria infection at present and most cases are travelers to endemic areas. In some cases, initial clinical diagnoses may not be correct because of a variety of symptoms, physical findings and laboratory abnormalities. A 67-year-old female, who had traveled to South American countries 2 months before the onset of the disease, presented with a case of vivax malaria. Because of the patient's high fever, profound thrombocytopenia (1.5 x 10(4)/microl), and elevated platelet-associated IgG on admission, our initial diagnosis was acute type idiopathic thrombocytopenic purpura (ITP). However, we recognized her tertian fever and plasmodial vivax in erythrocytes 4 days later. She responded promptly to anti-parasitic therapy after diagnosis of malaria and her laboratory data also improved. Travel history is indicative of malaria infection in some cases with thrombocytopenia mimicking acute ITP.

Tertian malaria (Plasmodium vivax and Plasmodium ovale) in two travelers despite atovaquone-proguanil prophylaxis

There is limited data regarding the efficacy of prophylaxis with atovaquone/proguanil (A/P) against non-falciparum malaria in travelers. Two cases, one Plasmodium vivax infection and another Plasmodium ovale infection, in travelers despite A/P prophylaxis are presented.

Assessing the genetic diversity of the aldolase genes of Plasmodium falciparum and Plasmodium vivax and its potential effect on performance of aldolase-detecting rapid diagnostic tests

Malaria-specific rapid diagnostic tests (RDTs) targeting aldolase show highly variable sensitivities. We assessed diversity in Plasmodium falciparum and P. vivax aldolases by sequencing the coding genes from parasites of various origins. The results show that aldolases are highly conserved, indicating that antigenic diversity is not a cause of variable RDT sensitivity.

Thrombocytopenia--an indicator of acute vivax malaria

Thrombocytopenia is frequently observed in vivax malaria but the exact mechanism has not been elucidated. We studied 27 cases of acute vivax malaria out of which 24 cases had thrombocytopenia. This was the most common hematological finding. None had bleeding from any site. Anaemia and splenomegaly were not present in any of the cases. Platelet counts reverted to normal on treatment. Other causes of thrombocytopenia were ruled out by complete history and physical examination, dengue serology and blood culture. DIC was ruled out by peripheral smear examination and measurement of FDP levels. Our study stresses the importance of thrombocytopenia as an early indicator for acute malaria; a finding that is frequent and present even before anemia and splenomegaly set in. The possible mechanisms leading to thrombocytopenia in malaria have been discussed which include immune mechanisms, oxidative stress, alterations in splenic functions and a direct interaction between plasmodium and platelets.

Avaliação da confiabilidade da gota espessa em um estudo de campo conduzido em uma área endêmica de malária no Médio Rio Negro, Estado do Amazonas

Com o objetivo de medir a confiabilidade da gota espessa em uma área de infecção pelo Plasmodium foi realizado um estudo no qual foram avaliadas 322 gotas espessas, lidas em condições normais de campo, por microscopista treinado. Posteriormente, as mesmas lâminas foram examinadas por outro microscopista que fez a leitura em condições ideais. A concordância foi medida usando o índice Kappa. Nos pacientes com sintomas de malária foi encontrada uma concordância de 0,91 (IC 95% 0,57-0,98 p<0,05) enquanto nos pacientes com infecção assintomática o valor do índice Kappa foi de 0,42 (IC 95% 0,15-0,68 p<0,05). Conclui-se que em áreas onde há infecção assintomática é fundamental aumentar a confiabilidade da gota espessa aumentando o número de campos lidos.

Amplification of LDH gene from indian strains of Plasmodium vivax

BACKGROUND & OBJECTIVES

Plasmodium vivax is geographically widespread and responsible for > 50% of malaria cases in India. Increased drug resistance of the parasite highlights the immediate requirement of early and accurate diagnosis as well as new therapeutics. In view of this, the present study was undertaken to amplify P. vivax (Indian strains) lactate dehydrogenase gene (PvLDH) which has been identified as a good target for antimalarials as well as diagnostics.

METHODS

P. vivax infected clinical blood samples were collected from southern part of India and were tested with established diagnostic parameters (ICT, Giemsa staining). Total DNA was extracted from blood samples and subjected to PCR using two sets of primers, one for the amplification of full PvLDH gene (951 bp) and the other for a partial PvLDH gene fragment (422bp), covering a variable antigenic region (140aa) as compared to other plasmodial species.

RESULTS & CONCLUSION

PCRs for both the full and partial gene targets were optimised and found to be consistent when tested on several P. vivax positive clinical samples. In addition, full gene PCR was found to specifically detect only P. vivax DNA and could be used as a specific molecular diagnostic tool. These amplified products can be cloned and expressed as a recombinant protein that might be useful for the development and screening of antimalarials as well as for diagnostic purposes.

Deployment of early diagnosis and mefloquine-artesunate treatment of falciparum malaria in Thailand: the Tak Malaria Initiative

BACKGROUND

Early diagnosis and treatment with artesunate-mefloquine combination therapy (MAS) have reduced the transmission of falciparum malaria dramatically and halted the progression of mefloquine resistance in camps for displaced persons along the Thai-Burmese border, an area of low and seasonal transmission of multidrug-resistant Plasmodium falciparum. We extended the same combination drug strategy to all other communities (estimated population 450,000) living in five border districts of Tak province in northwestern Thailand.

METHODS AND FINDINGS

Existing health structures were reinforced. Village volunteers were trained to use rapid diagnostic tests and to treat positive cases with MAS. Cases of malaria, hospitalizations, and malaria-related deaths were recorded in the 6 y before, during, and after the Tak Malaria Initiative (TMI) intervention. Cross-sectional surveys were conducted before and during the TMI period. P. falciparum malaria cases fell by 34% (95% confidence interval [CI], 33.5-34.4) and hospitalisations for falciparum malaria fell by 39% (95% CI, 37.0-39.9) during the TMI period, while hospitalisations for P. vivax malaria remained constant. There were 32 deaths attributed to malaria during, and 22 after the TMI, a 51.5% (95% CI, 39.0-63.9) reduction compared to the average of the previous 3 y. Cross-sectional surveys indicated that P. vivax had become the predominant species in Thai villages, but not in populations living on the Myanmar side of the border. In the displaced persons population, where the original deployment took place 7 y before the TMI, the transmission of P. falciparum continued to be suppressed, the incidence of falciparum malaria remained low, and the in vivo efficacy of the 3-d MAS remained high.

CONCLUSIONS

In the remote malarious north western border area of Thailand, the early detection of malaria by trained village volunteers, using rapid diagnostic tests and treatment with mefloquine-artesunate was feasible and reduced the morbidity and mortality of multidrug-resistant P. falciparum.

Diagnosis of mixed Plasmodium malariae and P. vivax infection in a development aid volunteer by examination of bone-marrow specimens by real-time PCR

Mixed Plasmodium malariae and P. vivax infections in humans are reported very infrequently. The case of a 27-year-old male who sustained malaria quartana/tertiana caused by an unbalanced mixed P. malariae-P. vivax infection is reported here. Conventional tests and serology for malarial parasites were uniformly negative. Identification and quantification of the parasites were accomplished by examining bone-marrow specimens using specific real-time TaqMan PCR.

Comparing the results of light microscopy with the results of PCR method in the diagnosis of Plasmodium vivax

BACKGROUND AND OBJECTIVES

Although polymerase chain reaction (PCR) is a new technique in the diagnosis of malaria with very high accuracy; light microscopy is still conventional diagnostic method in Iran. In this study we checked the accuracy of light microscopy using the results of PCR as gold standard in Iran.

METHODS

The blood samples were collected from 124 febrile cases in Kahnooj district. The blood slides were read by microscopists, and double checked by experts in provincial referral laboratory. DNA samples were processed by PCR to amplify species-specific sequences of 18s subunit ribosomal ribonucleic acid (18ssrRNA) genes of Plasmodium vivax and P. falciparum.

RESULTS

The sensitivity and specificity of microscopy in the detection of Plasmodium spp infection were 77% (95% CI: 46-94%) and 100% (95% CI: 95-100%), correspondingly. Also, the estimated positive and negative predictive values were 100% (95% CI: 66-100%) and 97% (95% CI: 91-99%), respectively.

INTERPRETATION AND CONCLUSION

According to these results, we believe that the accuracy of light microscopy in the diagnosis of malaria in Kahnooj was acceptable. Expert micorscopists in endemic areas of Iran such as Kahnooj and available equipments in one hand and expensive PCR test on the other hand may convince that in current situation we do not have to change the diagnostic method.

[Malaria: report of 12 non autochthonous cases]

Malaria is a protozoan infection caused by four Plasmodia species transmitted by female Anopheles mosquito. Nearly 40% of the world population is at risk of acquiring the disease because of increasing resistance to treatment, climate changes and travels to endemic zones. We report twelve patients with diagnosis of malaria, supported by the identification of parasites on blood smear. All cases had traveled to endemic zones (Peru, Ecuador, Central America, Africa), but only three used chemoprophylaxis. Seven cases were infected with Plasmodium vivax and five cases with P. falciparum. Three of latter required intensive care. All patients were treated with standard drugs according to the severity and Plasmodium specie, with excellent results and no mortality.

Diagnosing infection levels of four human malaria parasite species by a polymerase chain reaction/ligase detection reaction fluorescent microsphere-based assay

Improving strategies for diagnosing infection by the four human Plasmodium species parasites is important as field-based epidemiologic and clinical studies focused on malaria become more ambitious. Expectations for malaria diagnostic assays include rapid processing with minimal expertise, very high specificity and sensitivity, and quantitative evaluation of parasitemia to be delivered at a very low cost. Toward fulfilling many of these expectations, we have developed a post-polymerase chain reaction (PCR)/ligase detection reaction-fluorescent microsphere assay (LDR-FMA). This assay, which uses Luminex FlexMAP microspheres, provides simultaneous, semi-quantitative detection of infection by all four human malaria parasite species at a sensitivity and specificity equal to other PCR-based assays. In blinded studies using P. falciparum-infected blood from in vitro cultures, we identified infected and uninfected samples with 100% concordance. Additionally, in analyses of P. falciparum in vitro cultures and P. vivax-infected monkeys, comparisons between parasitemia and LDR-FMA signal intensity showed very strong positive correlations (r > 0.95). Application of this multiplex Plasmodium species LDR-FMA diagnostic assay will increase the speed, accuracy, and reliability of diagnosing human Plasmodium species infections in epidemiologic studies of complex malaria-endemic settings.

Anemia and thrombocytopenia in children with Plasmodium vivax malaria

Clinico-epidemiological features of pediatric patients with malaria due Plasmodium vivax that developed anemia and thrombocytopenia requiring hospitalization are herein reported. Over a 3-year period, 78 children with P. vivax infection were admitted to our Hospital in Sucre, Venezuela. Clinical manifestations at admission were 93.59 per cent fever, 41.03 per cent chills and 14.10 per cent headache, among others. On paraclinical evaluations 94.87 percent presented with anemia (10.26 per cent severe), 25.64 percent with malnutrition, and 10.26 percent had intestinal parasitosis. The mean hemoglobin levels on admission were 8.09 g/dl and mean platelet counts 127 402 cells/mm3. Among these patients 58.97 per cent developed thrombocytopenia (24.36 per cent severe) requiring transfusion in 25.64 per cent of patients. After antimalarial treatment with chloroquine and primaquine and supportive care all patients were successfully discharged. No deaths or further complications were seen, except for persistent mild thrombocytopenia in 17.95 per cent of the patients.

Standardization of a very specific and sensitive single PCR for detection of Plasmodium vivax in low parasitized individuals and its usefulness for screening blood donors

Here, we describe the standardization of a very sensitive and specific single Plasmodium vivax polymerase chain reaction (PCR) and its usefulness for diagnosis and screening procedures when a Plasmodium falciparum PCR was also utilized. The P. vivax PCR sensitivity threshold was 0.019 parasites per microliter, and a PCR fragment was only detected when P. vivax DNA was present. Among the 11 febrile patients with negative parasitological examination that attended the malaria service of Fundação de Medicina Tropical do Amazonas, we diagnosed one P. vivax malaria by PCR. Among the 286 individuals considered suitable for blood donation, we also detected by PCR an individual with P. vivax malaria, and conversely, we did not detect any malaria infection in blood donor candidates considered unsuitable due to its past malaria history. We conclude that PCR is the method of choice for low-parasitized individuals and could therefore represent a complementary tool to safely rescue blood donor candidates considered unsuitable on the basis of malaria history.

[Efficacy of a rapid test to diagnose Plasmodium vivax in symptomatic patients of Chiapas, Mexico]

OBJECTIVE

To evaluate, under laboratory conditions, the sensitivity and specificity of a rapid diagnostic test (OptiMAL), based on immunoreactive strips, to detect Plasmodium vivax infection in febrile patients in Southern Chiapas, Mexico.

MATERIAL AND METHODS

The presence of parasites in blood samples of 893 patients was investigated by Giemsa-stained thick blood smear microscopic examination (gold standard). A blood drop from the same sample was smeared on immunoreactive strips to investigate the presence of the parasite pLDH. Discordant results were resolved by PCR amplification of the parasite's 18S SSU rRNA, to discard infection.

RESULTS

OptiMAL had an overall sensitivity of 93.3% and its specificity was 99.5%. Its positive and negative predictive values were 96.5% and 98.9%, respectively. Signal intensity in OptiMAL strips correlated well with the parasitemia density in the blood samples (r = 0.601, p = 0.0001).

CONCLUSION

This rapid test had acceptable sensitivity and specificity to detect P. vivax under laboratory conditions and could be useful for malaria diagnosis in field operations in Mexico.

Malaria in a seaport worker in Haifa

A healthy port worker who had traveled to Azerbaijan 2 years previously was diagnosed with vivax malaria. This is most likely a case of seaport malaria, which has been reported only four times previously. The importance of obtaining a proper occupational, as well as travel, history when evaluating febrile patients is emphasized.

Comparative study of microscopic detection methods and haematological changes in malaria

Quantitative buffy coat (QBC) technique, thick smears, thin smears and conventional buffy coat smears were compared for malarial parasite detection. Of 200 blood samples studied, 70 (35%) samples were positive by QBC technique, 62 (31%) samples by thick smears, 50 (25%) samples by thin smears and only 34 (17%) samples were positive by conventional buffy coat technique. 8 (4%) samples detected by QBC technique alone, had low parasitic index. Haematological analysis was performed on samples positive for malarial parasite. Anaemia was present in 66 (94.28%) samples of which 37 (56.06%) were Plasmodium falciparum, 21 (31.81%) were Plasmodium vivax and 8 (12.12%) had mixed infection (Plasmodium falciparum and Plasmodium vivax). 35 (50%) cases showed normocytic normochromic anaemia. Majority of the samples showed normal total and differential leukocyte count. Thrombocytopenia was found in 49 (70%) samples of which 33 (67.34%) were Plasmodium falciparum.

Acute respiratory distress syndrome due to vivax malaria: case report and literature review

Severe pulmonary involvement in malaria has been frequently reported in cases of Plasmodium falciparum infection, but rarely in vivax malaria. Among the 11 previous cases of vivax-related severe respiratory involvement described in the literature, all except one developed it after the beginning of anti-malarial treatment; these appear to correspond to an exacerbation of the inflammatory response. We report the case of a 43-year-old Brazilian woman living in a malaria-endemic area, who presented acute respiratory distress syndrome (ARDS) caused by P. vivax before starting anti-malarial treatment. The diagnosis was made based on microscopic methods. A negative rapid immunochromatographic assay, based on the detection of Histidine Rich Protein-2 (HRP-2) of P. falciparum, indicated that falciparum malaria was unlikely. After specific anti-plasmodial therapy and intensive supportive care, the patient was discharged from the hospital. We conclude that vivax malaria-associated ARDS can develop before anti-malarial therapy.

Sources of variability in determining malaria parasite density by microscopy

Enumeration of parasites by microscopic examination of blood smears is the only method available for quantifying parasitemia in infected blood. However, the sources and scale of error inherent in this technique have not been systematically investigated. Here we use data collected in outpatient clinics in Peru and Thailand to elucidate important sources of variation in parasite density measurements. We show that discrepancies between readings from two independent microscopists and multiple readings from a single microscopist are inversely related to the density of the infection. We present an example of how differences in reader technique, specifically the number of white blood cells counted, can contribute to the differences between readings. We discuss the implications of this analysis for field studies and clinical trials.

Pseudo-borreliosis in patients with malaria

Malaria and relapsing fever are arthropod-borne infections characterized by fever, myalgia, headache, and a tendency to relapse. Both are diagnosed through examination of stained blood films, and both might respond to tetracycline therapy. In at least four published case reports, the presence of malarial microgametes possibly resulted in misdiagnosis of borreliosis in patients with malaria. An additional case is presented, and the mechanism of microgamete production in clinical specimens is discussed.

Occult Plasmodium vivax infection diagnosed by a polymerase chain reaction-based detection system: a case report

After a trip to Zambia, a previously healthy adult traveler presented with a prolonged illness characterized by low-grade fevers and fatigue. Although malaria smears and antibody tests results for Plasmodium species were negative, a diagnosis of malaria was ultimately determined by polymerase chain reaction (PCR) amplification and species-specific nucleic acid hybridization techniques. The patient was successfully treated and cured. Clinical use of PCR technology may facilitate the identification of cases of smear-negative malaria, which up to the present time, have been difficult to diagnose.

Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community

Background

There is a low incidence of malaria in Iquitos, Peru, suburbs detected by passive case-detection. This low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections.

Methods

Passive case-detection (PCD) during the malaria season (February-July) and an active case-detection (ACD) community-wide survey (March) surveyed 1,907 persons. Each month, April-July, 100-metre at-risk zones were defined by location of Plasmodium falciparum infections in the previous month. Longitudinal ACD and PCD (ACP+PCD) occurred within at-risk zones, where 137 houses (573 persons) were randomly selected as sentinels, each with one month of weekly active sampling. Entomological captures were conducted in the sentinel houses.

Results

The PCD incidence was 0.03 P. falciparum and 0.22 Plasmodium vivax infections/person/malaria-season. However, the ACD+PCD prevalence was 0.13 and 0.39, respectively. One explanation for this 4.33 and 1.77-fold increase, respectively, was infection clustering within at-risk zones and contiguous households. Clustering makes PCD, generalized to the entire population, artificially low. Another attributable-factor was that only 41% and 24% of the P. falciparum and P. vivax infections were associated with fever and 80% of the asymptomatic infections had low-density or absent parasitaemias the following week. After accounting for asymptomatic infections, a 2.6-fold increase in ACD+PCD versus PCD was attributable to clustered transmission in at-risk zones.

Conclusion

Even in low transmission, there are frequent highly-clustered asymptomatic infections, making PCD an inadequate measure of incidence. These findings support a strategy of concentrating ACD and insecticide campaigns in houses adjacent to houses were malaria was detected one month prior.

Diagnostic and prognostic utility of an inexpensive rapid on site malaria diagnostic test (ParaHIT f) among ethnic tribal population in areas of high, low and no transmission in central India

BACKGROUND

Malaria presents a diagnostic challenge in most tropical countries. Rapid detection of the malaria parasite and early treatment of infection still remain the most important goals of disease management. Therefore, performance characteristics of the new indigenous ParaHIT f test (Span diagnostic Ltd, Surat, India) was determined among ethnic tribal population in four districts of different transmission potential in central India to assess whether this rapid diagnostic test (RDT) could be widely applied as a diagnostic tool to control malaria. Beyond diagnosis, the logical utilization of RDTs is to monitor treatment outcome.

METHODS

A finger prick blood sample was collected from each clinically suspected case of malaria to prepare blood smear and for testing with the RDT after taking informed consent. The blood smears were read by an experienced technician blinded to the RDT results and clinical status of the subjects. The figures for specificity, sensitivity, accuracy and predictive values were calculated using microscopy as gold standard.

RESULTS

The prevalence of malaria infection estimated by RDT in parallel with microscopy provide evidence of the type of high, low or no transmission in the study area. Analysis revealed (pooled data of all four epidemiological settings) that overall sensitivity, specificity and accuracy of the RDT were >90% in areas of different endemicity. While, RDT is useful to confirm the diagnosis of new symptomatic cases of suspected P. falciparum infection, the persistence of parasite antigen leading to false positives even after clearance of asexual parasitaemia has limited its utility as a prognostic tool.

CONCLUSION

The study showed that the ParaHIT f test was easy to use, reliable and cheap. Thus this RDT is an appropriate test for the use in the field by paramedical staff when laboratory facilities are not available and thus likely to contribute greatly to an effective control of malaria in resource poor countries.

Diagnostic and therapeutic pitfalls associated with primaquine-tolerant Plasmodium vivax

We describe a U.S. Army Ranger returning from duty in Afghanistan and Iraq with life-threatening infection due to Plasmodium vivax. Morphological variants were observed in blood films prepared using samples collected by venipuncture. The patient's multiple relapses indicate infection with primaquine-tolerant P. vivax. Strategies for relapse prevention using primaquine are reviewed.

Pathogenesis and Management of a Late Manifestation of Vivax Malaria after Deployment to Afghanistan: Conclusions for NATO Armed Forces Medical Services

Because of the worldwide engagement of the German armed forces, tropical diseases may come to the attention of their medical services. In particular, acquired malarial infections, which sometimes become symptomatic only months or even years after soldiers return from military operations, need to be addressed. Other forces, such as the British, U.S., Australian, and Italian armed forces, reported cases of vivax malaria up to approximately 20 months after soldiers returned from military operations. The importance of a sound history and rapid diagnosis, leading to appropriate treatment, is emphasized in this case report of a 27-year-old German soldier who reported for sick call in his unit complaining of a flu-like illness, which later proved to be vivax malaria. The special parasitological features of Plasmodium vivax infection are discussed.

Rapid immunochromatography-based detection of mixed-species malaria infection in Pakistan

We report the identification of mixed Plasmodium infections in four recent patients with malaria clinically refractory to empiric chloroquine therapy using the rapid antigen detection kit, NOW ICT Malaria Pf/Pv. A rapid in vitro immunodiagnostic test, the NOW ICT Malaria Pf/Pv test kit was used for the detection of circulating Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) antigens in whole blood. Peripheral blood microscopy confirmed mixed-species infection in all the cases. Thick and thin peripheral blood films were made and stained with Giemsa stain and examined by both hospital laboratory staff and an experienced parasitologist who was blinded to the results of the rapid malarial antigen tests. Four recent patients (all male; mean age, 24 years) with mixed malarial infection were identified. All the subjects were males working for an oil company in a coastal area of Pakistan, and all had been diagnosed presumptively with malaria based on clinical grounds (without microbiologic confirmation), and were treated empirically with chloroquine without clinical response. Semiquantitative malaria counts via microscopy were as follows: P. vivax, scanty (2 patients) and moderate (2 patients); for P. falciparum--scanty (1 patient), moderate (2 patients), and heavy (1 patient). The present case series, although limited by the small number of patients with proven mixed P. falciparum-P. vivax infection, highlights the usefulness of the rapid antigen test in a highly malarious region of Pakistan where chloroquine resistance is prevalent. Although there was full concordance between the results of blood smear microscopy and rapid antigen testing, these techniques are potentially most useful when there is a discrepancy with microscopy findings. Accurate and rapid diagnosis of parasites, particularly in cases of mixed P. falciparum and P. vivax infection, is of immense importance for individual patient management and in reducing the burden of disease, especially in regions of chloroquine resistance.

Status febrilis mit Bewusstlosigkeit

Cerebral malaria with Plasmodium vivax is uncommon. Normally Plasmodium falciparum is the cause of cerebral malaria. We report about a 18 year old patient from Pakistan with a history of intermittent fever for several months. The patient recovered within a few days; however prognosis can be severe when cerebral malaria is complicating the course of Plasmodium vivax infection.

Plasmodium vivax malaria

We report 11 cases of severe Plasmodium vivax malaria in Bikaner (western India). Patients exhibited cerebral malaria, renal failure, circulatory collapse, severe anemia, hemoglobinurea, abnormal bleeding, acute respiratory distress syndrome, and jaundice. Peripheral blood microscopy, parasite antigen-based assays, and parasite 18s rRNA gene-based polymerase chain reaction showed the presence of P. vivax and absence of P. falciparum.

[A transfusion-transmitted malaria case]

Malaria is a rare but potentially serious complication of blood transfusion. In this report a transfusion-transmitted malaria case has been presented. A 47-years-old woman admitted to our clinic with the complaints of striking fever with chills, diarrhea and vomiting. She had history of an operation and transfusion before 10 days of admission. On physical examination jaundice, splenomegaly and abdominal tenderness were detected. Laboratory results revealed anemia, and elevated LDH and bilirubin levels. Examination of thin blood films yielded Plasmodium vivax trophozoites. Chloroquine was initiated for therapy and the patient was successfully treated. On the other hand, informations about her blood donor indicated that he had been in the military service in Southeast Anatolia of Turkey where malaria is endemic. All the efforts to reach the donor, for his diagnosis and treatment, were failed. Since our region (Northeast Anatolia) is not an endemic area for malaria and the patient had no travel history to an endemic area, it has been considered that the transmission route of malaria in this case was blood transfusion. In conclusion, as there are no available approved tests for malaria screening of donations, the transfusion-transmitted malaria can only be prevented by careful questioning of the donors.

Identification and characterization of an interspersed repetitive DNA fragment in Plasmodium vivax with potential use for specific parasite detection

We cloned and characterized a Plasmodium vivax repeat element of 7872bp named PvRE7.8. Several internal tandem repeats were found along the sequence. The repetitive nature of the PvRE7.8 element was confirmed by hybridization of a P. vivax YAC library. Based on the data bank analysis and the presence of two contiguous putative genes that may encode proteins related to DNA metabolism, PvRE7.8 could be considered an inactivated transposon-LINE element. By using Pv79 as probe or primers derived from Pv79-flanking sequences, P. vivax DNA Could be detected from whole blood and mosquito samples. We consider that the repeat element described here has potential for P. vivax malaria diagnosis and for epidemiological analysis of P. vivax transmission areas.

Automated detection of malaria by means of the haematology analyser CoulterR GEN.STM

The haematology analysers Coulter(R) GEN.S(TM) and LH(TM) give a set of data--'positional parameters'--which define each WBC population by mean of index values, the mean and the standard deviation (SD) of volume, conductivity and scatter, used to identify the WBC populations. These parameters were analysed in patients investigated for suspicion of malaria, in order to show a difference between malaria negative and malaria positive patients and to use it for malaria detection. The six parameters exhibiting a significant difference between the two groups were submitted to a ROC analysis, which showed both sensitivity >90% and specificity >60% for two parameters, lymphocyte and monocyte SDs of volumes. A discriminator combining the two parameters showed a sensitivity of 96.9% and a specificity of 82.5%. The cut off of the discriminative value was calculated. Because of the good stability and reproducibility of the parameters selected, the test can be used in order to detect patients having a high probability to be malaria positive and to pay particular attention to these blood smears. For more extensive diagnostic use, a standard control procedure of the positional parameters should be introduced.

Travel histories as risk factors in the analysis of urban malaria in Colombia

Self-reported travel histories were used in a case-control study to determine whether movement of local residents to neighboring endemic areas was a risk factor for malaria in the town of Quibdo, Colombia. Multivariate analyses showed that among residents of Quibdo, traveling to an endemic area 8-14 days before disease onset was the strongest risk factor for both Plasmodium falciparum (adjusted odds ratio [OR] = 28.96, 95% confidence interval [CI] = 13.9-60.32) and P. vivax (adjusted OR = 14.24, 95% CI = 5.27-38.46) malaria. For P. falciparum, individuals who did not travel outside Quibdo during the 8-14 days before disease onset, but who reported traveling 1-7, 15-21, or 22-30 days before disease onset also had an increased risk of malaria. Conversely, use of protection against mosquitoes was negatively associated with P. falciparum. These results highlight the need for malaria control measures that target mobile populations. A definition of imported malaria that allows distinction of imported from autochthonous cases in Quibdo town is proposed.

Relative utility of dipsticks for diagnosis of malaria in mesoendemic area for Plasmodium falciparum and P. vivax in northeastern India

For diagnosis of malaria, popular brands of rapid test kits collectively termed as "dipsticks" were subject to field evaluation in northeastern India for their comparative sensitivity and specificity vis-à-vis conventional microscopic results. Dipsticks based on Plasmodium falciparum-specific histidine-rich protein (Pf HRP-2) antigen capture assay revealed 100% sensitivity and high specificity (94-100%); thus, they were concluded to be reliable tools for confirmed diagnosis of malarial infection. However, an advanced version of the same kit, having incorporated additional pan-malarial monoclonal antibody, was found to be less sensitive (71%) for non-falciparum infections. Besides, Pf HRP-2-based kits continued to show positive results up to day 7, even after clearance of parasitemia on account of persistent antigenemia. This very limitation seemed to have been overcome by parasite-specific lactate dehydrogenase (pLDH) enzyme-based kit. This kit was observed to have high sensitivity (81-89%) and specificity (100%) for both falciparum and non-falciparum malaria, but cannot distinguish mono-infection from mixed infections. It is concluded that the rational use of these kits would accord health benefits in terms of early detection and prompt treatment, reduce drug pressure, and possibly delay the emergence and spread of multi-drug-resistant strains of malarial parasites.

Evaluation of the rapid diagnostic test OptiMAL for diagnosis of malaria due to Plasmodium vivax

OBJECTIVE

To determine the sensitivity and specificity of the rapid diagnostic test OptiMAL for diagnosis of Plasmodium vivax malaria.

MATERIAL AND METHODS

We included all the patients who sought medical attention in the San Martin Pangoa Hospital, Junin, an area endemic for vivax malaria in Peru, between October and December 1998, who had fever during the previous 72 hours and who were older than 12 months. The gold standard for diagnosis was thick blood film microscopy. We determined the parasitemia rate for each of the positive slides. We calculated sensitivity, specificity, positive predictive value and negative predictive value of the test.

RESULTS

We included 72 patients; 39 of them were positive for P. vivax by microscopic examination. The sensitivity of the Optimal test was 92.3%, the specificity 100%, the positive predictive value 100% and the negative predictive value 91.6%. The accuracy of the test was 95.8%. The sensitivity of the OptiMAL test progressively decreased when parasitemia was lower than 1,000 parasites/microliter.

CONCLUSIONS

the OptiMAL test has a high sensitivity and specificity for diagnosis of P. vivax malaria. However, its sensitivity decreased when parasitemia levels were lower. It is a very simple technique, which makes it a good alternative for malaria diagnosis in remote places, although its elevated cost is still a problem.

Thrombocytopenia in malaria

Malaria continues to be a cause of high mortality and morbidity. Imported cases of malaria are increasing in New York City. Yet, New York physicians, when evaluating patients for fever, frequently missed the diagnosis of malaria. We evaluated the role of platelet count for predicting malarial infection. The study included patients seen between 1996 and 2000 in a New York community hospital for fever who had traveled to a malaria-endemic area. Forty patients with malaria were identified. Our study found the sensitivity of platelet count for diagnosing malaria was 100%, and the specificity was 70%. The negative predictive value was 100% and the positive predictive valve was 86%. Hence, we propose that in any patient with fever and recent travel history, platelet count is an important clue to the diagnosis of malaria. A finding of thrombocytopenia should increase the suspicion of malaria and lead to performance of more specific tests, including multiple peripheral smears and ELISA for parasite-specific antigen, etc.

Exflagellation of microgametocytes in Plasmodium vivax malaria: a diagnostic conundrum

OBJECTIVE

To present a clinical diagnostic conundrum of unidentified structures in a blood smear from a patient with Plasmodium vivax malaria.

CLINICAL PRESENTATION AND INTERVENTION

A 37-year-old Ethiopian male presented with a 4-month history of chills, chronic diarrhea and weight loss. He was diagnosed with P. vivax malaria, advanced HIV infection and Isospora belli enteritis. Unidentified structures initially confusing to the diagnosticians were seen in blood smears taken on admission. The structures were initially considered to represent atypical spirochetes, but were later identified as microgametes and other exflagellation forms of P. vivax. The patient recovered after receiving adequate treatment for his infections.

CONCLUSION

This case illustrates that exflagellation may be observed in blood smears from patients with P. vivax malaria. Size and morphological characteristics differentiate malaria microgametes and other exflagellation forms from microfilaria, spirochetes and trypanosomes.

Evaluation of a rapid whole blood immunochromatographic assay for the diagnosis of Plasmodium falciparum and Plasmodium vivax malaria

OBJECTIVE

Microscopic examination of blood smears is the 'gold standard' for malaria diagnosis, but is labour intensive and requires skilled operators. Plasmodium vivax malaria accounts for up to 70% of infections in Sri Lanka. The objective of this study was to determine the effectiveness of an immunochromatographic test which can detect both the species of Plasmodium, P. vivax and P. falciparum, present in Sri Lanka.

DESIGN

Prospective study from May 2001 to March 2002.

SETTING AND METHODS

All persons above 5 years of age who presented to the Malaria Research Station, Kataragama or the Anti-malaria Clinic, Kurunegala, with a history of fever were recruited to the study. Thick and thin blood smears were examined for malarial parasites. The rapid diagnostic test (RDT), ICT Malaria P.f/P.v (AMRAD ICT, Australia) was performed simultaneously by an independent investigator. The severity of clinical disease of all patients was evaluated.

RESULTS

The study sample comprised 328 individuals of whom 126 (38%) were infected, 102 with P. vivax (31.1%) and 24 with P. falciparum (7.3%). The RDT was found to be highly sensitive (100%) and specific (100%) for the diagnosis of P. falciparum when compared with field microscopy. The sensitivity for the diagnosis of P. vivax malaria was only 70%. When P. vivax parasitaemia was greater than 5000 parasites/microL the RDT was 96.2% sensitive. A significant association was noted between the band intensity on the dipstick and both peripheral blood parasitaemia (p < 0.001) and clinical severity of disease with P. vivax (p = 0.011).

CONCLUSIONS

The ICT Malaria P.f/P.v test can be used in Sri Lanka in the absence of microscopists.

Thrombocytopenia in malaria--correlation with type and severity of malaria

AIM OF THE STUDY

Malaria is a major health problem in the tropics with increased morbidity and mortality. Thrombocytopenia is a common finding in malaria. Although a reliable diagnostic marker, prognostic implications could vary in the two types of malaria. This study was undertaken to correlate the presence and severity of thrombocytopenia with the type of malaria.

DESIGN

A total of 1565 subjects were included in the study and identified positive for malaria parasites on peripheral smear examination with conventional microscopy. Platelet count was done on a fully automated, quantitative, hematology Coulter analyser.

RESULTS

Normal platelet count was noted in 21.6% cases. The mean platelet count in vivax malaria (n=973) was 1,15,390/microl (SD 64,580) with a range of 8000-5,73,000/microl, as against falciparum malaria (n=590) where the mean platelet count was 100,900/microl (SD 75,437) with a range of 2000-497,000/microl (Pearson coefficient 8.825, p < 0.0001). Platelet count < 20,000/microl was noted in only 1.5% cases in vivax malaria as against 8.5% cases of falciparum malaria, and none of the subjects with vivax malaria had a platelet count less than 5000/microl.

CONCLUSION

Although absence of thrombocytopenia is uncommon in malaria, its presence is not a distinguishing feature between the two types. Thrombocytopenia less than 20,000/microl can occur in P. vivax malaria although statistically more common with P. falciparum malaria. The above findings can have therapeutic implications in context of avoiding unnecessary platelet infusions with the relatively more benign course in P. vivax malaria.

Epidemiology of malaria presenting at British Columbia's Children's Hospital, 1984-2001: lessons for prevention

BACKGROUND

Few studies have examined the epidemiology of imported malaria in Canadian children. Identifying populations at increased risk in Canada would enable targeted malaria prevention strategies within those groups. The study objective was to describe the epidemiology of malaria diagnosed at British Columbia's Children's Hospital (BCCH) between 1984 and 2001.

METHODS

This was a retrospective chart review of malaria cases identified at BCCH and confirmed through the British Columbia Centre for Disease Control. Demographic and clinical data were recorded on a standardized form.

RESULTS

Malaria was diagnosed 42 times in 40 children (age 24 days to 14.8 years). Thirty cases (71.4%) occurred in 28 Canadian residents, and 12 (28.6%) occurred in immigrant or refugee children. Twenty-six children (65%) were male. Thirty-one children (77.5%) were of East Indian descent. Thirty-three exposures (78.6%) to malaria occurred in the Indian subcontinent. Plasmodium vivax was identified in 37 cases (88.1%), P. falciparum in 3 (7.1%), and the species was unknown in 2 (4.8%). Fourteen cases in the resident children (46.7%) reported pre-travel counselling. Ten resident cases (33.3%) were prescribed chemoprophylaxis, primarily chloroquine, and at least six of them (60%) were non-compliant. The duration of symptoms prior to diagnosis was < 7 days in 27 cases (64.3%), 8 to 30 days in 10 (23.8%), > 30 days in 4 (9.5%) and the duration was unknown in 1 (2.5%). Twenty-four of 36 cases (66.7%) had seen 2 to more than 4 doctors before the diagnosis of malaria was made.

CONCLUSION

The majority of children in our review were of East Indian origin and were exposed to malaria in India. Most had not sought or had received inadequate pre-travel counselling and had been non-compliant with chemoprophylaxis. As malaria is a potentially lethal but preventable disease, strategies to ensure adequate pre-travel counselling for high-risk groups are required.

A cost analysis of the use of the rapid, whole-blood, immunochromatographic P.f/P.v assay for the diagnosis of Plasmodium vivax malaria in a rural area of Sri Lanka

Between May 2001 and March 2002, a prospective study was conducted in a malaria-endemic area of Sri Lanka, to determine the cost implications of using the immunochromatographic P.f/P.v test to detect Plasmodium vivax infection. All consecutive subjects aged >5 years who presented with a history of fever were recruited. Each was checked for P. vivax infection by the standard microscopical examination of bloodsmears and by the immunochromatographic test (ICT). The costs of diagnosis using each method and the sensitivity, specificity and predictive values of the ICT (with bloodsmear examination used as the 'gold standard') were estimated, the costs/case detected being simulated for different slide positivity 'rates' and ICT sensitivities. In the detection of P. vivax, the ICT had a sensitivity of 70% and a specificity of 99%. The costs of the ICT per subject investigated and per case detected were, respectively, approximately 14 and 20 times more than those of bloodsmear examination. The costs of the ICT per case detected would fall as the sensitivity of the test increased. The ICT gave relatively few false-positive results. The current, relatively high cost of the ICT is the most important barrier to its routine operational use in the diagnosis of malaria. The test is already useful, however, in specific situations.

Comparison of the OptiMAL rapid antigen test with field microscopy for the detection of Plasmodium vivax and P. falciparum: considerations for the application of the rapid test in Afghanistan

To establish the sensitivity and specificity of a batch of 'OptiMAL 48' rapid antigen tests procured by the World Health Organization in Afghanistan, a sample was tested, in parallel with routine, microscopical diagnosis, at basic health units (BHU) within Afghan refugee camps in Pakistan. The results of both methods of field diagnosis were compared with those of cross-checking microscopy at a reference laboratory, which were taken as the 'gold standard'. Out of 499 patients examined, 36% were diagnosed as malaria cases by field microscopy and 34% by the rapid test. For the OptiMAL 48 test, cross-checking of the corresponding smears at the reference laboratory gave a sensitivity of 79.3% and a specificity of 99.7% for Plasmodium falciparum and corresponding values of 86.1% and 98.7% for P. vivax infections. The performance of the field microscopy was better, with a sensitivity and specificity of 85.2% and 99.7% for P. falciparum, and 90.4% and 98.7% for P. vivax, respectively. These results show that the performance of OptiMAL 48 is adequate for acute- and post-emergency situations when the alternative is just clinical diagnosis. However, in the developing health system of Afghanistan, the main focus should be on the expansion of the existing network for microscopical diagnosis and quality control, to meet the needs of a stable situation. Rapid antigen tests are more suited to investigations of outbreaks in remote situations, where health services are deficient or absent.