Vivax Mono-infection Research Articles

A Case of Vivax Malaria Complicated by Adult Respiratory Distress Syndrome and Successful Management with Extracorporeal Membrane Oxygenation

Complicated malaria is mainly caused by Plasmodium falciparum, but, increasingly, Plasmodium vivax is also being reported as a cause. Since the reemergence of indigenous vivax malaria in 1993, cases of severe malaria have been steadily reported in Korea. Herein, we report a case of vivax malaria complicated by adult respiratory distress syndrome (ARDS) that was successfully managed with extracorporeal membrane oxygenation (ECMO). A 59-year-old man presented at our hospital with fever and abdominal pain, which had persisted for 10 days. On admission, the patient had impaired consciousness, shock, hypoxia and haziness in both lungs, jaundice, thrombocytopenia and disseminated intravascular coagulation, metabolic acidosis, and acute kidney injury. A peripheral blood smear and a rapid diagnostic test verified P. vivax mono-infection. Ten hours after admission, hypoxia became more severe, despite providing maximal ventilatory support. The administration of antimalarial agents, ECMO, and continuous venovenous hemofiltration resulted in an improvement of his vital signs and laboratory findings. He was discharged from the hospital 7 weeks later, without any sequelae.

Adherence to human lung microvascular endothelial cells (HMVEC-L) of Plasmodium vivax isolates from Colombia

BackgroundFor years Plasmodium vivax has been considered the cause of benign malaria. Nevertheless, it has been observed that this parasite can produce a severe disease comparable to Plasmodium falciparum. It has been suggested that some physiopathogenic processes might be shared by these two species, such as cytoadherence. Recently, it has been demonstrated that P. vivax-infected erythrocytes (Pv-iEs) have the capacity to adhere to endothelial cells, in which intercellular adhesion molecule-1 (ICAM-1) seems to be involved in this process.MethodsAdherence capacity of 21 Colombian isolates, from patients with P. vivax mono-infection to a microvascular line of human lung endothelium (HMVEC-L) was assessed in static conditions and binding was evaluated at basal levels or in tumor necrosis factor (TNF) stimulated cells. The adherence specificity for the ICAM-1 receptor was determined through inhibition with an anti-CD54 monoclonal antibody.ResultsThe majority of P. vivax isolates, 13 out of 21 (61.9%), adhered to the HMVEC-L cells, but P. vivax adherence was at least seven times lower when compared to the four P. falciparum isolates. Moreover, HMVEC-L stimulation with TNF led to an increase of 1.6-fold in P. vivax cytoadhesion, similar to P. falciparum isolates (1.8-fold) at comparable conditions. Also, blockage of ICAM-1 receptor with specific antibodies showed a significant 50% adherence reduction.ConclusionsPlasmodium vivax isolates found in Colombia are also capable of adhering specifically in vitro to lung endothelial cells, via ICAM-1 cell receptor, both at basal state and after cell stimulation with TNF. Collectively, these findings reinforce the concept of cytoadherence for P. vivax, but here, to a different endothelial cell line and using geographical distinct isolates, thus contributing to understanding P. vivax biology.

Plasmodium vivax associated severe malaria complications among children in some malaria endemic areas of Ethiopia.

BackgroundAlthough, Plasmodium vivax is a rare parasite in most parts of Africa, it has significant public health importance in Ethiopia. In some parts of the country, it is responsible for majority of malaria associated morbidity. Recently severe life threatening malaria syndromes, frequently associated to P. falciparum, has been reported from P. vivax mono-infections. This prompted designing of the current study to assess prevalence of severe malaria complications related to P. vivax malaria in Ethiopia.MethodsThe study was conducted in two study sites, namely Kersa and Halaba Kulito districts, located in southwest and southern parts of Ethiopia, respectively. Children, aged ≤ 10 years, who visited the two health centers during the study period, were recruited to the study. Clinical and demographic characteristics such as age, sex, temperature, diarrhea, persistent vomiting, confusion, respiratory distress, hepatomegaly, splenomegaly, hemoglobinuria, and epitaxis were assessed for a total of 139 children diagnosed to have P. vivax mono-infection. Parasitological data were collected following standard procedures. Hemoglobin and glucose level were measured using portable hemocue instrument.ResultsMedian age of children was 4.25 ± 2.95 years. Geometric mean parasite count and mean hemoglobin level were 4254.89 parasite/μl and 11.55 g/dl, respectively. Higher prevalence rate of malaria and severe malaria complications were observed among children enrolled in Halaba district (P < 0.001). However, severe parasitemia was higher (72.4%) among children who visited Serbo health center (Kersa district). Male children had significantly higher risk of malaria infection (OR = 1.9, 95% CI, 1.08 to 3.34), while female had higher risk to anemia (OR = 1.91, 95% CI, 1.08 - 3.34). The observed number of anemic children was 43%, of which most of them were found in age range from 0–3 years. Furthermore, P. vivax malaria was a risk factor for incidence of anemia (P < 0.05) in the two sites.ConclusionP. vivax associated severe malaria complications observed in this study was lower than those reported from other countries. However, incidence of severe malaria complications in one of the sites, Halaba district, where there is highest treatment failure to first line drug, could have significant impact on national malaria prevention and control activities.

In Vivo Efficacy of Artemether-Lumefantrine and Chloroquine against Plasmodium vivax: A Randomized Open Label Trial in Central Ethiopia

Background In vivo efficacy assessments of antimalarials are essential for ensuring effective case management. In Ethiopia, chloroquine (CQ) without primaquine is the first-line treatment for Plasmodium vivax in malarious areas, but artemether-lumefantrine (AL) is also commonly used.Methods and FindingsIn 2009, we conducted a 42-day efficacy study of AL or CQ for P. vivax in Oromia Regional State, Ethiopia. Individuals with P. vivax monoinfection were enrolled. Primary endpoint was day 28 cure rate. In patients with recurrent parasitemia, drug level and genotyping using microsatellite markers were assessed. Using survival analysis, uncorrected patient cure rates at day 28 were 75.7% (95% confidence interval (CI) 66.8–82.5) for AL and 90.8% (95% CI 83.6–94.9) for CQ. During the 42 days of follow-up, 41.6% (47/113) of patients in the AL arm and 31.8% (34/107) in the CQ arm presented with recurrent P. vivax infection, with the median number of days to recurrence of 28 compared to 35 days in the AL and CQ arm, respectively. Using microsatellite markers to reclassify recurrent parasitemias with a different genotype as non-treatment failures, day 28 cure rates were genotype adjusted to 91.1% (95% CI 84.1–95.1) for AL and to 97.2% (91.6–99.1) for CQ. Three patients (2.8%) with recurrent parasitemia by day 28 in the CQ arm were noted to have drug levels above 100 ng/ml.ConclusionsIn the short term, both AL and CQ were effective and well-tolerated for P. vivax malaria, but high rates of recurrent parasitemia were noted with both drugs. CQ provided longer post-treatment prophylaxis than AL, resulting in delayed recurrence of parasitemia. Although the current policy of species-specific treatment can be maintained for Ethiopia, the co-administration of primaquine for treatment of P. vivax malaria needs to be urgently considered to prevent relapse infections.Trial RegistrationClinicalTrials.gov NCT01052584

Rosetting in Plasmodium vivax: A Cytoadhesion Phenotype Associated with Anaemia

Background Plasmodium vivax can potentially lead to life-threatening episodes but the mechanisms underlying severe disease remain poorly defined. Cytoadhesion of infected erythrocytes may contribute to P. vivax sequestration and organ injury although its physiological impact is still unknown. Here, we aimed to describe clinically-relevant cytoadhesive phenotypes of P. vivax isolates.Methodology/Principal findingsRosetting and adhesion to CSA, CD36, ICAM1, placental and brain cryosections were determined in P. vivax peripheral isolates from 12 pregnant women, 24 non-pregnant women and 23 men from Manaus (Brazil). P. falciparum co-infection was excluded by PCR and P. vivax isolates were genotyped by assessing the size polymorphism of microsatellites ms2, ms20 and msp1F3 through capillary electrophoresis of PCR products. P. vivax monoinfection was confirmed by PCR in 59 isolates, with 50 (85%) of them being single-clone infections. One P. vivax haplotype was more frequently found among pregnant women (33%) than in non-pregnant women (0%) and men (4%; p = 0.010). Rosetting was observed in 64% of the isolates, adhesion to CSA in 15%, to ICAM1 in 12% and to placental cryosections in 9%, being similar among pregnant and non-pregnant groups. Intensity of rosetting was higher among anaemic individuals compared to non-anaemic (p = 0.010) and decreased with increasing haematocrit (p = 0.033) and haemoglobin levels (p = 0.015).Conclusions/Significance P. vivax peripheral isolates from pregnant women do not exhibit a prominent adhesion to CSA, although other parasite phenotypes still unknown may increase the propagation of certain P. vivax clones observed among pregnant hosts. Rosetting is a frequent cytoadhesive phenotype in P. vivax infections that may contribute to the development of anaemia.

Severe sepsis and septic shock due to Plasmodium vivax infection

Plasmodium vivax malaria is typically characterized by a mild and benign clinical course. Organ dysfunction is rarely seen, whereas acute lung injury has been found to occur after starting antimalarial treatment. We present an unusual case of severe sepsis and septic shock due to Plasmodium vivax monoinfection.

Clinico-laboratory profile of severe Plasmodium vivax malaria in a tertiary care centre in Kolkata

Background:Vivax malaria is the most widely distributed human malaria and is responsible for up to 400 million infections every year. Recently, it has become evident that Plasmodium vivax monoinfection could also result in multiple organ dysfunction and severe life-threatening disease as seen in Plasmodium falciparum infection.Materials and Methods:The aim of this study was to note the different clinical and biochemical profiles of adult patients with the severe vivax malaria with regards to complications and outcome. This was a prospective observational study carried out at a tertiary care hospital in Kolkata over 9 month's period. Detailed history and examination findings were noted in all patients. Their clinical presentations, complications, course in ward until discharge or death was noted.Results:A total of 900 cases of vivax malaria were included in the study. Severe disease was present in 200 (22.2%) cases of malaria. There were 108 (54%) patients with single complication (SC) and 92 (46%) patients with the multiple complications (MC). Patients with SC had jaundice (48.1%) followed by cerebral involvement (25.9%), renal failure (7.4%), and pulmonary involvement (3.7%). The MC was found in various combinations and the majority (47.8%) had constellation of two different complications. The mortality rate of patients with the SC and MC was 7.4% and 34.8%. The overall mortality observed in severe vivax malaria was 20% (40/200).Conclusions:In recent years, the clinical pattern of vivax malaria has changed. Severe vivax malaria is now very common with increasing mortality. Not only the number, but also the type of complication influences the outcome of complicated malaria.

Postrenal transplant Plasmodium vivax malaria: neglected and not benign

Plasmodium vivax is causing increasingly more cases of severe malaria worldwide. We reported a case of postrenal transplantation acute kidney injury (AKI) associated with P. vivax, a neglected human malaria parasite. The diagnosis of P. vivax monoinfection was confirmed by direct visualization of the parasite in blood smear and rapid diagnostic test. On admission, serum creatinine (SCr.) increased from 1.45 to 3.7mg/dl. The other etiologies of fever and AKI were ruled out. He responded to prompt therapy with antimalarial drugs. There was no change in tacrolimus trough level before and after antimalarial drugs. Two weeks after discharge, his SCr. was 1.43mg/dl. Our patient lived in an endemic malarial area and the transplant took place in December 2010. The patient subsequently presented with clinical malaria in June 2012, so we thought that posttransplantation transmission by the mosquito was a possibility and very less likely that other dormant form of the parasite had been the source of the clinical infection. P. vivax can lead to as AKI in renal transplant recipient. P. vivax should be considered in the differential diagnosis of fever in transplant recipients who had received organs or blood products from malaria-endemic area to facilitate a prompt diagnosis and adequate treatment.

Molecular survey of pathogenic trypanosomes in naturally infected Nigerian cattle

Microscopy and polymerase chain reaction (PCR) were used to survey pathogenic trypanosome infection in naturally infected Nigerian cattle. In 411 animals sampled, microscopy detected 15.1% positive infection of at least one of Trypanosoma brucei, Trypanosoma congolense or Trypanosoma vivax, while PCR detected 63.7% positive infections of at least one of those species and Trypanosoma evansi. PCR detected 4.4%, 48.7%, 26.0% and 0.5% respectively of T. brucei, T. congolense, T. vivax and T. evansi infections. All of the T. congolense detected were savannah-type, except for two forest-type infections. Prevalence of mixed infections was 13.9%, being primarily co-infection by T. congolense and T. vivax while prevalence of mixed infections by T. evansi, T. vivax and T. congolense was 1.5%. Microscopy showed poor sensitivity but specificity greater than 94%. Infection rates were much higher in Southern than in Northern Nigeria. Infections were lowest in N’dama compared to Muturu, Sokoto Gudali and White Fulani breeds. Animals with T. vivax monoinfection and mixed infections showed significantly lower packed cell volume (PCV) values. Those infected with any Trypanosoma species with <200 parasites/μl showed higher PCV values than those infected with >200 parasites/μl. The new finding of savannah- and forest- type T. congolense in Nigeria and the relatively high abundance of mixed infections are of significant clinical relevance. This study also suggests that T. congolense is the most prevalent species in Nigeria.

Placental Infection With Plasmodium vivax: A Histopathological and Molecular Study

Evidence of the presence of Plasmodium vivax in the placenta is scarce and inconclusive. This information is relevant to understanding whether P. vivax affects placental function and how it may contribute to poor pregnancy outcomes. Histopathologic examination of placental biopsies from 80 Papua New Guinean pregnant women was combined with quantitative polymerase chain reaction (qPCR) to confirm P. vivax infection and rule out coinfection with other Plasmodium species in placental and peripheral blood. Leukocytes and monocytes/macrophages were detected in placental sections by immunohistochemistry. Monoinfection by P. vivax and Plasmodium falciparum was detected by qPCR in 8 and 10 placentas, respectively. Seven of the 8 women with P. vivax placental monoinfection were negative in peripheral blood. By histology, 3 placentas with P. vivax monoinfection showed parasitized erythrocytes in the intervillous space but no hemozoin in macrophages nor increased intervillous inflammatory cells. In contrast, 7 placentas positive for P. falciparum presented parasites and hemozoin in macrophages or fibrin as well as intervillous inflammatory infiltrates. Plasmodium vivax can be associated with placental infection. However, placental inflammation is not observed in P. vivax monoinfections, suggesting other causes of poor delivery outcomes associated with P. vivax infection.

Plasmodium vivax malaria admissions and risk of mortality in a tertiary-care children’s hospital in North India

Background: In 2010, there was an increase in the severity of malaria admissions to Kalawati Saran Children’s Hospital, New Delhi and this report describes the morbidity and mortality profile.Method: A retrospective chart review of patients admitted with parasitologically confirmed malaria between January and December 2010.Results: There were 156 cases: P. vivax 105 (67·3%), P. falciparum 39 (25%) and mixed infections 12 (7·7%). Thrombocytopenia (platelet count <150×109/L) was present in 90 (85·7%) patients with P. vivax mono-infection. There were 91 (58·3%) patients with severe malaria: P. vivax mono-infection 46 (50·5%), P. falciparum mono-infection 35 (38·5%) and mixed 10 (11%). Severe anaemia and severe thrombocytopenia (platelet count <20×109/L) were detected significantly more often in P. falciparum and P. vivax mono-infection, respectively. Complications including cerebral malaria, acute renal failure, shock, acute respiratory distress syndrome (ARDS) and multiple-organ dysfunction syndrome (MODS) were similar in both groups. The mortality rate of around 20% was similar in severe P. vivax and P. falciparum mono-infection. Risk of mortality in vivax malaria was highest in patients with ARDS followed by MODS and shock.Conclusion: Increased morbidity owing to P. vivax malaria was observed and risk of mortality was highest in patients with ARDS and MODS.

An unusual case of Plasmodium vivax malaria monoinfection associated with crescentic glomerulonephritis: a need for vigilance

Plasmodium vivax infection is increasingly a major public health burden and the second most frequent human malaria. Higher levels of clinical severity and chloroquine resistance are major factors responsible for such increases. Malarial glomerular injury is uncommon and mainly observed in Plasmodium malariae-infected patients. Occasionally, transient immune complex-mediated glomerulonephritis is associated with Plasmodium falciparum infection. Coexistent crescentic glomerulonephritis and vivax malaria have not previously been reported. We report a fatal case of P. vivax malaria, who presented with acute renal failure. P. vivax monoinfection status was diagnosed with peripheral blood smear and rapid antigen test. Further evaluation for renal failure related to systemic illness and immunological markers were inconclusive. He was treated with antimalarial drugs, hemodialysis, and supportive therapy. Renal biopsy performed for nonrecovering renal failure reveled crescentic glomerulonephritis. This case highlights the need to thoroughly search for malaria-associated crescentic glomerulonephritis using renal biopsy after nonrecovering renal failure.

Postmortem Characterization of Patients With Clinical Diagnosis of Plasmodium vivax Malaria: To What Extent Does This Parasite Kill?

Severe disease attributable to Plasmodium vivax infection is already well described worldwide; however, autopsies in these patients are scarce. From 1996 to 2010, 19 patient deaths with a clinical diagnosis of P. vivax infection occurred in a tertiary care center in the Brazilian Amazon. Seventeen of these 19 deaths were fully autopsied. Clinical charts, macroscopic autopsy reports, and stored paraffinized tissue blocks were retrieved. Nested polymerase chain reaction was performed in paraffinized samples of spleen and lung to confirm P. vivax monoinfection. Immunohistofluorescence was used to detect P. vivax parasitized red blood cells (RBCs). Of 17 autopsies, 13 revealed that death could be attributed to P. vivax infection; in the remaining 4, acute diseases other than malaria were found to be the cause of death. The primary complication in patients in which malaria contributed to death was acute respiratory distress syndrome (ARDS) and pulmonary edema associated with the accumulation of neutrophils in the interalveolar space (6 cases). Spleen rupture (3 cases) and multiorgan dysfunction syndrome (3 cases) were the second most common complications. One child evolving with coma was also characterized, but no parasite was detected in the brain tissue. In one patient who developed ARDS and presented negative peripheral parasitemia by the time of death, scattered parasitized red blood cells were seen inside pulmonary capillaries, suggesting some sequestration in the lung. In 13 of 17 deceased patients, P. vivax infection was the plausible cause of death. However, more studies are needed to understand pathogenesis related to severe disease.

Renal cortical necrosis and acute kidney injury associated with Plasmodium vivax: a neglected human malaria parasite

Plasmodium vivax is causing increasingly more cases of severe malaria worldwide. There is an urgent need to reexamine the clinical spectrum and burden of P. vivax so that adequate control measures can be implemented against this emerging but neglected disease. Herein, we report a case of renal acute cortical necrosis and acute kidney injury (AKI) associated with P. vivax monoinfection. Her initial serum creatinine was 7.3 mg/dL on admission. Modification of Diet in Renal Disease (MDRD) Study glomerular filtration rate (GFR) value was 7 mL/min/1.73 m(2) (normal kidney function-GFR above 90 mL/min/1.73 m(2) and no proteinuria). On follow-up, 5 months later, her SCr. was 2.43 mg/dl with no proteinuria. MDRD GFR value was 24 mL/min/1.73 m(2) suggesting severe chronic kidney disease (CKD; GFR less than 60 or kidney damage for at least 3 months), stage 4. Our case report highlights the fact that P. vivax malaria is benign by name but not always by nature. AKI associated with P. vivax malaria can lead to CKD. Further studies are needed to determine why P. vivax infections are becoming more severe.

Risk Factors and Characterization of Plasmodium Vivax-Associated Admissions to Pediatric Intensive Care Units in the Brazilian Amazon

Background Plasmodium vivax is responsible for a significant proportion of malaria cases worldwide and is increasingly reported as a cause of severe disease. The objective of this study was to characterize severe vivax disease among children hospitalized in intensive care units (ICUs) in the Western Brazilian Amazon, and to identify risk factors associated with disease severity.Methods and FindingsIn this retrospective study, clinical records of 34 children, 0–14 years of age hospitalized in the 11 public pediatric and neonatal ICUs of the Manaus area, were reviewed. P. falciparum monoinfection or P. falciparum/P. vivax mixed infection was diagnosed by microscopy in 10 cases, while P. vivax monoinfection was confirmed in the remaining 24 cases. Two of the 24 patients with P. vivax monoinfection died. Respiratory distress, shock and severe anemia were the most frequent complications associated with P. vivax infection. Ninety-one children hospitalized with P. vivax monoinfections but not requiring ICU were consecutively recruited in a tertiary care hospital for infectious diseases to serve as a reference population (comparators). Male sex (p = 0.039), age less than five years (p = 0.028), parasitemia greater than 500/mm3 (p = 0.018), and the presence of any acute (p = 0.023) or chronic (p = 0.017) co-morbidity were independently associated with ICU admission. At least one of the WHO severity criteria for malaria (formerly validated for P. falciparum) was present in 23/24 (95.8%) of the patients admitted to the ICU and in 17/91 (18.7%) of controls, making these criteria a good predictor of ICU admission (p = 0.001). The only investigated criterion not associated with ICU admission was hyperbilirubinemia (p = 0.513)].ConclusionsOur study points to the importance of P. vivax-associated severe disease in children, causing 72.5% of the malaria admissions to pediatric ICUs. WHO severity criteria demonstrated good sensitivity in predicting severe P. vivax infection in this small case series.

Changing Profile of Severe Malaria in North Indian Children

To look for profile of severe malaria and contribution of vivax infection to malarial morbidity in North Indian children. Detailed clinical, biochemical and hematological characteristics of children hospitalized with severe malaria over last 3 y were recorded. Presence of malarial parasite on peripheral smear and/or positive antigen test was considered as diagnostic for malaria. A total of 131(55.3%) patients with Plasmodium vivax (Pv), 79 (33.3%) with Plasmodium falciparum (Pf) and 27 (11.4%) with mixed infections were admitted. Cerebral malaria, severe anemia and shock were significantly more frequently observed in Pf group, while hepatic, renal, respiratory, and bleeding complications were more commonly seen in Pv patients. Malaria mortality was highest in mixed infection (11.1%), followed by Pf (7.6%) and Pv (3%) group. Severe and fatal vivax malaria is an emerging recognized entity and challenges the perception of Pv as a benign disease. Further clinical studies and molecular research is required to understand emergence of severe malaria in vivax mono-infection.

Phenotyping clinical resistance to chloroquine in Plasmodium vivax in northeastern Papua, Indonesia

Chloroquine (CQ)-resistant Plasmodium vivax was first documented in 1989 and threatens much of eastern Indonesia, with>50% of therapeutic failure rates. We screened 2236 subjects for malaria infection through active case detection and identified 232 infected cases with 100 subjects carried P. vivax mono infection. We prospectively evaluated therapeutic responses to CQ in 73 subjects infected by P. vivax in northeastern Papua, Indonesia. We phenotyped these infections as susceptible or resistant to CQ using a 28-day in vivo test format. Eighteen subjects (25%) had persistent or recurrent parasitemia during the test and were provisionally classified as resistant. Among the remainder, 46 (63%) subjects had no persistent or recurrent parasitemia and were classified as having infections sensitive to CQ, 4 were lost to follow up, and 5 dropped out. Among the 18 provisionally resistant cases, 1 subject (6%) had persistent parasitemia at Day 3 and was considered as a direct treatment failure, 2 subjects (11%) had recurrent parasitemia by Day 7 and were considered early treatment failures, and 7 (39%) and 8 (44%) had recurrent parasitemia by Days 14 and 28, respectively. Analysis of blood for CQ+N-desethylchloroquine (DCQ) levels on day of recurrence from 15 of the 18 with treatment failures showed 11 subjects having CQ+DCQ blood levels⩾100ng/ml and 2 with CQ+DCQ blood levels<100ng/ml. The 28-day cumulative incidence of therapeutic failure likely due to parasite resistance was 17.5%. These findings affirm P. vivax resistance to CQ in eastern Indonesia, albeit at lower levels than reported elsewhere. This simple means of phenotyping P. vivax infections could be implemented in other malaria endemic areas of Indonesia.

Clinical profiles of 13 children withPlasmodium vivaxcerebral malaria

Bikaner region is endemic for both P. vivax and P. falciparum malaria. Usually, cerebral malaria is caused by P. falciparum but it has been reported recently also in P. vivax mono-infection. Epidemiologic studies and clinical descriptions of P. vivax cerebral malaria in children are rare. To describe the clinical features of PCR-confirmed cerebral malaria owing to P. vivax mono-infection and its clinico-laboratory profile in Bikaner, Northwest India. This observational prospective study was based on detailed clinical and laboratory investigation of children admitted with cerebral malaria owing to P. vivax between November 2008 and December 2010. Cerebral malaria was categorised according to the WHO (2000) criteria for P. falciparum and the diagnosis of P. vivax mono-infection was established by peripheral blood film and rapid diagnostic tests and confirmed by polymerase chain reaction. The possibility of other diseases/infections causing similar illness were investigated thoroughly. Thirteen children with P. vivax cerebral malaria were studied, eight of whom (61·5%) had multi-organ (two or more organs) dysfunction. Other associated severe manifestations included severe anaemia (7), hepatic dysfunction (2), renal dysfunction (2), bleeding manifestation (2), respiratory distress (2), metabolic acidosis (2) and shock (one). Hypoglycaemia was not observed in any patient. There was no evidence of neurological sequelae. All the children were managed according to WHO guidelines using intravenous artisunate. Thrombocytopenia was detected in five and hyponatraemia in four children. P. vivax mono-infection can cause cerebral malaria and multi-organ dysfunction.

Improved performance with saliva and urine as alternative DNA sources for malaria diagnosis by mitochondrial DNA-based PCR assays

Saliva and urine from malaria-infected individuals contain trace amounts of Plasmodium DNA, and therefore, could be used as alternative specimens for diagnosis. A nested PCR targeting the mitochondrial cytochrome b gene (Cytb-PCR) of four human malaria species and Plasmodium knowlesi was developed and tested with 693 blood samples from febrile patients living in diverse malaria-endemic areas of Thailand, and compared with microscopy and nested PCR targeting small-subunit rRNA (18S-PCR). Cytb-PCR was 16% and 39.8% more sensitive than 18S-PCR and microscopy, respectively, in detecting all of these malarial species in blood samples. Importantly, 34% and 17% of Plasmodium falciparum and Plasmodium vivax mono-infections, respectively, detected by microscopy were, in fact, mixed P. falciparum and P. non-falciparum infections. Analysis of matched blood, saliva and urine from 157 individuals showed that microscopy and Cytb-PCR of saliva yielded no significant difference in detecting P. falciparum and P. vivax. However, Cytb-PCR of saliva was more sensitive than microscopy for diagnosis of mixed-species infections. A combination of Cytb-PCR of saliva and of urine significantly outperformed microscopy (p 0.0098 for P. falciparum, p 0.006 for P. vivax, and p 0.0002 for mixed infections). Furthermore, Plasmodium malariae and P. knowlesi could also be identified in saliva and urine with this method. Therefore, the Cytb-PCR developed herein offers a high potential for the use of both saliva and urine for malaria diagnosis, with a sensitivity comparable with or superior to that of microscopy.

Thrombocytopenia in childhood malaria with special reference to P. vivax monoinfection: A study from Bikaner (Northwestern India)

Thrombocytopenia is commonly seen in Plasmodium vivax malaria, but its prognostic value has not been addressed in children. This prospective study included 676 admitted children of malaria [Plasmodium falciparum (Pf) monoinfection 262, Plasmodium vivax (Pv) monoinfection 380, and mixed (Pf + Pv) infection 34], in which thrombocytopenia (platelet count <150 × 103/mm3 on admission) was found in 442 (65.38%) children [Pf monoinfection 55.3% (145/262), Pv monoinfection 73.16% (278/380), and mixed infection 55.88% (19/34)]. The association of thrombocytopenia was statistically significant with Pv monoinfection [73.16% (278/380)] in comparison to either Pf monoinfection [55.34% (145/262); odds ratio (OR) = 2.199 (95% confidence interval (CI) 1.577–3.068), p < 0.0001] or mixed infection [55.88% (19/34); OR = 2.152 (95%CI 1.054–4.394), p = 0.032]. In Pv monoinfection, thrombocytopenia was highest in 0–5 years age group and subsequently decreased with advancing age, whereas in Pf monoinfection it was reverse. Severe thrombocytopenia (platelet count <20 × 103/mm3) was present in 16.52% (73/442) children [Pv monoinfection 21.58% (60/278) and Pf monoinfection 8.97% (13/145)]. The risk of developing severe thrombocytopenia was also highest in Pv monoinfection [15.79% (60/380)] in comparison to Pf monoinfection [10.59% (13/262); OR = 3.591 (95%CI 1.928–6.690), p < 0.0001]. Bleeding manifestations were associated in 21.27% (94/442) children [Pf monoinfection 9.92% (26/262), Pv monoinfection 16.58% (63/380), and mixed malaria 14.71% (5/34)]. All the children having bleeding manifestations had thrombocytopenia but low platelet counts were not always associated with abnormal bleeding. The association of severe malaria was significantly more among children having Pv monoinfection with platelet counts <20 × 103/mm3 [OR = 2.569 (95%CI 1.196–5.517), p < 0.014] with specificity of 88.3% and positive predictive value of 85%. Till today, thrombocytopenia is not included in severe malaria criterion described by WHO, but when platelet counts <20 × 103/mm3, we advocate it to include as one of the severe malaria criteria.