Severe anemia in Papua New Guinean children from a malaria-endemic area: a case-control etiologic study

Human parvovirus B19 infection in a Plasmodium vivax endemic area on the Brazil-French Guiana border

While human parvovirus B19 (B19V) infection is widespread in Brazil, over 99 % of reported malaria cases occur in the Amazon region, mainly by Plasmodium vivax. As B19V infection may contribute to anemia in children living in P. falciparum endemic areas, this study aimed to investigate the impact of B19V/P. vivax coinfection in residents of the municipality of Oiapoque, Amapá, Brazil. A total of 300 serum samples collected in 2014-2015, from individuals infected by P. vivax (n = 148) and non-infected (n = 152), were tested for B19V by serologic and molecular methods. Hemoglobin dosage and cytokine levels were evaluated by automatic method and flow cytometry/ELISA, respectively. Acute B19V infection was diagnosed in 56.8 % (84/148) of infected with P. vivax and 38.2 % (58/152) of non-infected individuals (p < 0.01), and P. vivax was considered a risk factor for B19V infection (OR=2.19; 95 % CI; p = 0.001). Participants were grouped into: B19V/P. vivax coinfected (CO), P. vivax monoinfected (M), B19V monoinfected (B19V), and endemic control (EC) who were negative for both agents. A significant association was found between the CO group and lower hemoglobin levels (RRR= 0.66; 95 % CI; p = 0.0019), but no link was found between anemia and coinfection. It was found that higher gametocyte counts (OR=1.002; 95 % CI; p = 0.0164), IL-5 (RRR=1.74, 95 % CI; p = 0.025) and IL-10 (RRR=1.45; 95 % CI; p = 0.004) levels were strongly associated with the CO group. No difference in viral load was observed between the CO and B19V groups. Our study highlights the importance of monitoring the circulation of B19V in P. vivax endemic areas.

The association of intraleucocytic malaria pigment and disease severity in Papua New Guinean children with severe P. falciparum malaria

BACKGROUND

Plasmodium falciparum pigment-containing leucocytes (PCLs) are associated with adverse clinical manifestations of severe malaria in African children. However, limited data exist on the association of PCLs in settings outside of Africa.

METHODS

Thin films on peripheral blood slides obtained from children ages 6 months-10 y with severe malaria were examined for PCLs. The intraleucocytic pigment data were correlated with clinical phenotypic data such as severe anaemia, metabolic acidosis and coma to determine the association of PCLs with clinical phenotypes of severe malaria and outcome.

RESULTS

Of the 169 children with severe P. falciparum malaria confirmed by microscopy, 76% (129/169) had PCLs. Compared with children without PCLs, the presence (adjusted odds ratio [AOR] 3.2 [95% confidence interval {CI} 1.5 to 6.9], p≤0.01) and quantity (AOR 1.0 [95% CI 1.0 to 1.1], p=0.04) of pigment-containing monocytes (PCMs) was significantly associated with severe anaemia, while the quantity of both PCMs (AOR 1.0 [95% CI 1.0 to 1.1], p≤0.01) and pigment-containing neutrophils (AOR 1.0 [95% CI 1.0 to 1.1], p=0.01) was significantly associated with metabolic acidosis. Plasma P. falciparum histidine-rich protein-2 level negatively correlated with the platelet count (r=-0.5, p≤0.01) in patients with PCLs and no PCLs.

CONCLUSIONS

In Papua New Guinean children with severe P. falciparum malaria, the presence and quantity of PCLs are predictors of disease severity, severe anaemia and metabolic acidosis.

A Health Survey Revealing Prevalence of Vector-Borne Diseases and Tuberculosis in Papua New Guinea Defence Force Personnel and Families

The Papua New Guinean Defence Force (PNGDF) and the Australian Defence Force (ADF) work and train closely. Infectious diseases pose a health threat to both forces, but recent knowledge about the risk at military bases in Papua New Guinea is limited. To improve understanding, a collaborative cross-sectional survey was conducted (March-April 2019) at Lombrum Naval base (Manus province) and Moem Army barracks (Wewak, East Sepik province) plus its Vanimo outpost (Sandaun province). Clinical data, venous blood, and sputum were collected from PNGDF personnel (DF) from the three sites, with point-of-care testing conducted for malaria (microscopy and rapid diagnostic test [RDT]), lymphatic filariasis (RDT), glucose-6-phosphate-dehydrogenase (G6PD) deficiency (RDT), tuberculosis (GeneXpert), and hemoglobin level. Finger prick blood collected from family members residing at the Wewak base was tested for malaria and hemoglobin level. Overall, 235 DF and 793 family members completed the survey. Microscopy revealed malaria prevalence as 0.4% Plasmodium falciparum and 3.1% Plasmodium vivax among DF and 3.5% P. falciparum, 14.3% P. vivax, and 0.3% mixed P. falciparum/P. vivax among family members. Among DF, 3.9% were G6PD deficient and none tested positive for tuberculosis or for lymphatic filariasis antigen. Anemia was present in 6.5% of DF and 47.3% of family members, predominantly females. Results suggest ongoing exposure to malaria, particularly P. vivax, at study sites, whereas infections of lymphatic filariasis and tuberculosis were not detected. Survey results will inform the PNGDF and the ADF regarding vector-borne disease risk for future sustainable health and disease control interventions.

Quantifying differences in iron deficiency-attributable anemia during pregnancy and postpartum

Pregnant women in resource-limited settings are highly susceptible to anemia and iron deficiency, but the etiology of postpartum anemia remains poorly defined. To inform the optimal timing for anemia interventions, changes in iron deficiency-attributable anemia through pregnancy and postpartum need to be understood. In 699 pregnant Papua New Guinean women attending their first antenatal care appointment and following up at birth and 6 and 12 months postpartum, we undertake logistic mixed-effects modeling to determine the effect of iron deficiency on anemia and population attributable fractions, calculated from odds ratios, to quantify the contribution of iron deficiency to anemia. Anemia is highly prevalent during pregnancy and 12 months postpartum, with iron deficiency increasing the odds of anemia during pregnancy and, to a lesser extent, postpartum. Iron deficiency accounts for ≥72% of anemia during pregnancy and 20%-37% postpartum. Early iron supplementation during and between pregnancies could break the cycle of chronic anemia in women of reproductive age.

Multinomial logistic regression analysis of the determinants of anaemia severity among children aged 6-59 months in Ghana: new evidence from the 2019 Malaria Indicator Survey

BACKGROUND

Anaemia among children under age five is a major public health issue. Although anaemia prevalence is declining in Ghana, the severity among anaemic children is worsening. This study aims to investigate the determinants of anaemia severity among children aged 6 to 59 months in Ghana.

METHOD

The study utilized a weighted sample of 1,258 children with anaemia with data obtained from the 2019 Ghana Malaria Indicator Survey. The predictor variables included maternal, household child and health system characteristics. SPSS version. At the multivariate level, three different multinomial logistic models were run with selected predictor variables. All tests were conducted at the 95% confidence level.

RESULTS

The overall anaemia prevalence among children under age five was 43.5%. Of these, 2.6% were severely anaemic, 48.5% were moderately anaemic, and 48.9% had mild anaemia. The multinomial analysis showed that maternal, household, child and health system factors significantly predicted anaemia levels among anaemic children. The results indicate that a lower likelihood of anaemia severity is likely to be found among children whose mothers belong to Pentecostal/Charismatic faith (AOR = 0.18-model I; AOR = 0.15-model III) and children who tested negative for malaria (AOR = 0.28-model II and III). Again, a higher probability of anaemia severity was found among anaemic children whose mothers were not aware of NHIS coverage of malaria (AOR = 2.41-model II, AOR = 2.60-model III). With regard to moderate anaemia level, children who belong to the poorest, poorer and middle household wealth index had a higher likelihood of being moderately anaemic compared to those in rich households. Similarly, anaemic children who were less than 12 months old (AOR = 2.21-model II, AOR = 2.29-model III) and those between the ages of 1-2 years (AOR = 1.84-model II, AOR = 1.83-model III) were more likely to have moderate anaemia levels.

CONCLUSION

The study findings show the importance of understanding the interrelation among different factors that influence anaemia severity among children under age five as critical in developing strategies and programmes aimed at addressing childhood anaemia.

Age-specific differences in the magnitude of malaria-related anemia during low and high malaria seasons in rural Zambian children

Background

Malaria causes anemia by destruction of red blood cells and inhibition of erythropoiesis.

Objective

We assessed whether the magnitude of the malaria-specific effect on anemia differs by age, during low and high malaria seasons.

Method

In rural Zambian children participating in a pro-vitamin A efficacy trial, we estimated differences in the prevalence of anemia (defined as hemoglobin < 110 g/L for children < 60 months. and < 115 g/L in older children) by malaria status and assessed malaria-age interactions. Regression models (with anemia as the outcome) were used to model malaria-age interaction in both the low and high malaria seasons, controlling for potential confounders.

Results

Average age was 68 months at baseline (n = 820 children). In the low malaria season, anemia prevalence was 29% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with no malaria-age interactions (p = 0.44). In the high malaria season, anemia prevalence was 41% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with significant malaria-age interactions (p = 0.02 for anemia). Age-stratified prevalence of anemia in malaria positive versus negative children was 67.0% versus 37.1% (in children < 60 months); 57.0% versus 37.2% (in 60-69 months.); 46.8% versus 37.2% (in 70-79 months.); 37.0% versus 37.3% (in 80-89 months) and 28.0% versus 37.4% (in 90+ months).

Conclusions

Malarial anemia is most severe in younger children, especially when transmission is intense. Anemia control programs must prioritize this vulnerable group.

Severe Anemia Is Associated with Systemic Inflammation in Young Children Presenting to a Tertiary Hospital in Uganda

The role of inflammation in severe anemia (SA) in African children has not been well characterized. We conducted a study to evaluate risk factors for SA in young children admitted at a tertiary unit in Uganda. Clinical, infectious, and micronutrient risk factors for anemia, along with markers of inflammation, were evaluated in children aged < 5 years in Jinja Hospital, Uganda. Participants included 284 children with SA (Hemoglobin [Hb] < 5.0 g/dL), and two control groups: 63 children admitted with acute illness without SA (Hb > 9.3 g/dL) and 53 asymptomatic community control children. Appropriate logistic analysis was performed to determine factors associated with SA. Of the 284 children with SA, 36.5% had Plasmodium falciparum parasitemia, 32.7% had blackwater fever (one of the types of severe malaria), and 15.5% had vitamin B12 deficiency. HIV infection, bacteremia, hookworm infection, severe acute malnutrition, and folate deficiency were relatively uncommon (each accounting for < 8%). Factors independently associated with SA compared with the combined control groups included (adjusted odds ratio [OR]; 95% CI) the following: P. falciparum parasitemia (OR: 4.3; 95% CI: 1.4-13.8), total white blood count (OR: 1.3; 95% CI: 1.1-1.4), C-reactive protein (OR: 1.8; 95% CI: 1.3-2.4), and ferritin (OR: 2.7; 95% CI: 1.9-4.0). In this area of Uganda, malaria and markers of inflammation were independently associated with SA in children. Additional studies are required to determine the role of inflammation in children with SA in this population.

A cross-sectional study on risk factors for infection with Parvovirus B19 and the association with anaemia in a febrile paediatric population in Ghana

Parvovirus B19 (B19V) occurs globally and can cause severe anaemia. The role of co-infections with Plasmodium falciparum (P. falciparum) has been controversially discussed. The study aimed to determine prevalence and severity of B19V infection, and the effect of co-infections on the risk for anaemia. Between November 2013 and April 2015 a total of 1186 hospital visits of children with fever admitted to a hospital in Ghana were recorded. Malaria, B19V and additional diagnostics for fever causes were performed. Recent B19V infection was defined as PCR and/or IgM positivity. Risk factors for a B19V infection and for anaemia were analysed. The prevalence of anaemia was compared between children with/without B19V infection, stratified for the presence of malaria. B19V IgM/PCR was positive in 6.4% (n = 76; 40 IgM + , 30 PCR + , 6 IgM + and PCR +). Among the B19V cases 60.5% had a simultaneous P. falciparum infection. B19V IgM positivity but not PCR positivity was associated with moderate-severe anaemia (OR = 2.6; 95%-CI: 1.3-5.3; P < 0.01 vs. OR = 0.9; 95%-CI: 0.4-1.8; P = 0.70). P. falciparum and IgM positive B19V infection were independent risk factors for anaemia with no evidence of effect modification. Our data show a significant association between B19V infection, defined as IgM but not PCR positivity, and moderate-severe anaemia. A multiplicative effect of B19V and P. falciparum infection was not found.

Blackwater Fever in Ugandan Children With Severe Anemia is Associated With Poor Postdischarge Outcomes: A Prospective Cohort Study

BACKGROUND

Blackwater fever (BWF), one of the complications of severe malaria, has recently re-emerged as a cause of severe anemia (SA) in African children. However, postdischarge morbidity in children with BWF has previously not been described.

METHODS

This was a descriptive cohort study in which children, aged 0-5 years, admitted to Jinja Regional Referral Hospital with acute episodes of SA (hemoglobin ≤5.0 g/dL) were followed up for 6 months after hospitalization. Incidence of readmissions or deaths during the follow-up period was compared between SA children with BWF and those without BWF.

RESULTS

A total of 279 children with SA including those with BWF (n = 92) and no BWF (n = 187) were followed for the duration of the study. Overall, 128 (45.9%) of the study participants were readmitted at least once while 22 (7.9%) died during the follow-up period. After adjusting for age, sex, nutritional status, and parasitemia, SA children with BWF had higher risk of readmissions (hazard ratio [HR], 1.68; 95% confidence interval [CI], 1.1-2.5) and a greater risk of death (HR. 3.37; 95% CI, 1.3-8.5) compared with those without BWF. Malaria and recurrence of SA were the most common reasons for readmissions.

CONCLUSIONS

There is a high rate of readmissions and deaths in the immediate 6 months after initial hospitalization among SA children in the Jinja hospital. SA children with BWF had increased risk of readmissions and deaths in the postdischarge period. Postdischarge malaria chemoprophylaxis should be considered for SA children living in malaria endemic areas.

Severe childhood anemia and emergency blood transfusion in Gadarif Hospital, eastern Sudan

BACKGROUND

Anemia is a major cause of global morbidity and mortality, particularly among children. Management of anemia depends on causes and severity of anemia. However blood transfusion is a lifesaving intervention in severe and life-threatening anemia. There are no published data on blood transfusion for anemia in Sudan.

METHODS

A descriptive study was conducted in Gadarif Hospital in eastern Sudan during 1 August, 2017 to 31 March, 2018. Consecutive children who presented at the emergency room with an indication for blood transfusion were enrolled in the study. A detailed history was gathered from all patients. Physical examinations, including vital signs, were performed. The World Health Organization guidelines for blood transfusion were followed.

RESULTS

During the study period, a total of 1800 children were admitted to the emergency pediatric ward in Gadarif Hospital and were assessed for anemia, 513 (28.5%) were anemic and 141 (7.8%) had severe anemia. Three hundred anemic children received blood transfusion. The median (interquartile) of the age of the 300 children who received blood transfusion was 4.2 4.2(2.0-9.0) years. A total of 148 (49.3%) of the children were boys and 151 (50.3%) were younger than 5 years. The diagnoses associated with the order for blood transfusion were sickle cell disease (129, 43.0%), active bleeding (58, 19.3%), malaria (50, 16.7%), visceral leishmaniasis (25, 8.3%), severe acute malnutrition (16, 5.30%), snake bite (11, 3.7%), sepsis (5, 1.7%), and others. Two hundred eighty-five (95.0%) children improved, nine children were discharged against medical advice, and six (2.0%) children died.

CONCLUSION

There is a high burden of anemia in eastern Sudan. Sickle cell disease, malaria, and visceral leishmaniasis are the main causes of anemia in this region. Further research on blood transfusion is needed.

Community perceptions of paediatric severe anaemia in Uganda

Background

Severe anaemia remains a major cause of morbidity and mortality among children in sub-Saharan Africa. There is limited research on the beliefs and knowledge for paediatric severe anaemia in the region. The effect of these local beliefs and knowledge on the healthcare seeking of paediatric severe anaemia remains unknown.

Objective

To describe community perceptions of paediatric severe anaemia in Uganda.

Methods

Sixteen in-depth interviews of caregivers of children treated for severe anaemia and six focus group discussions of community members were conducted in three regions of Uganda between October and November 2017.

Results

There was no common local name used to describe paediatric severe anaemia, but the disease was understood in context as ‘having no blood’. Severe anaemia was identified to be a serious disease and the majority felt blood transfusion was the ideal treatment, but concomitant use of traditional and home remedies was also widespread. Participants articulated signs of severe pediatric anemia, such as palmar, conjunctival, and tongue pallor. Other signs described included jaundice, splenomegaly, difficulty in breathing and poor appetite. Poor feeding, malaria, splenomegaly and evil spirits were perceived to be the common causes of severe anaemia. Other causes included: human immunodeficiency virus (HIV), haemoglobinuria, fever, witchcraft, mosquito bites, and sickle cell. Splenomegaly and jaundice were perceived to be both signs and causes of severe anaemia. Severe anaemia was interpreted to be caused by evil spirits if it was either recurrent, led to sudden death, or manifested with cold extremities.

Conclusion

The community in Uganda perceived paediatric severe anaemia as a serious disease. Their understanding of the signs and perceived causes of severe anaemia to a large extent aligned with known clinical signs and biological causes. Belief in evil spirits persists and may be one obstacle to seeking timely medical care for paediatric severe anaemia.

Validation of a Dried Blood Spot Ceftriaxone Assay in Papua New Guinean Children with Severe Bacterial Infections

Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK) studies in situations where venous blood sampling is logistically and/or ethically challenging. In this study, we aimed to demonstrate the validity of a DBS ceftriaxone assay in a PK study of children with severe illness from Papua New Guinea (PNG), a setting in which health care resources are limited and anemia is common. Using a previously validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay, serial plasma and DBS ceftriaxone concentrations were measured in PNG children aged 5 to 10 years with acute bacterial meningitis or severe pneumonia. The concentration-time data were incorporated into population PK models. Ten children were recruited with an admission hematocrit of 0.22 to 0.52. Raw data demonstrated good correlation between plasma and DBS concentrations (Spearman's rank correlation coefficient [r_s] = 0.94 [95% confidence interval, 0.91 to 0.97], P < 0.0001). A marked systematic hematocrit bias was observed, with lower hematocrits resulting in underestimation of DBS-predicted plasma concentration. After adjustment for red cell partitioning and hematocrit bias, a population PK model comparing plasma and DBS-predicted plasma concentrations did not differ in terms of key PK parameters, including clearance, volume of distribution, and residual variability. The performance of the ceftriaxone DBS assay is robust and provides reassurance that this platform can be used as a surrogate for plasma concentrations to provide valid PK and PK/pharmacodynamic studies of severely unwell children hospitalized in a resource-limited setting. It highlights the importance of hematocrit bias in validation studies of DBS assays.

Intergenerational influences on childhood anaemia

Prior research on assessing intergenerational influences on child anaemia has largely approached it from purely maternal perspective. Although there is much merit to focus on that, it is an extremely limited/reductionist view of understanding intergenerational influences. We expanded the intergenerational influences to include the fathers and overall of intergenerational household transfers. We analysed a sample of 19,619 mother-father-offspring trios from the 2015-2016 Indian National Fertility and Health Survey with available data on haemoglobin (Hb). Multinomial logistic regression models were used to establish associations between parent anaemia, household characteristics, and categories of offspring anaemia. Maternal and paternal Hb was measured as in children using a finger prick blood sample. The primary outcome was child's Hb level (in g/dl) and grades of anaemia defined as mild (10-10.9 g/dl), moderate (7-9.9 g/dl), and severe (<7 g/dl). Mean Hb was 10.1 g/dl for children, 14.2 g/dl among fathers, and 11.4 g/dl among mothers. Hb correlation was 0.1 between fathers and offspring and 0.2 between mothers and offspring (P < 0.001 for all correlations). Maternal-paternal Hb correlations were consistent across quintiles of wealth index. Maternal anaemia was associated with odds ratio of 1.3 (95% CI [1.1, 1.4]) and 1.6 (95% CI [1.4, 1.7]) for childhood mild and moderate/severe anaemia, respectively. Paternal mild anaemia was associated with an odds ratio of 1.1 (95% CI [0.9, 1.4]) and 1.4 (95% CI [1.2, 1.7]) for child moderate/severe anaemia. The clustering of poor circumstances suggests that public health strategies target social deprivation at the household level. A comprehensive perspective will provide holistic interventions to control childhood anaemia.

High rate of inappropriate blood transfusions in the management of children with severe anemia in Ugandan hospitals

BACKGROUND

Severe anaemia (SA) is a common reason for hospitalisation of children in sub-Saharan Africa but the extent to which blood transfusion is used appropriately in the management of severe anemia has hitherto remained unknown. We report on the use of blood transfusion in the management of anemic children in two hospitals in Uganda.

METHODS

Inpatient records of children 0-5 years of age admitted to Lira and Jinja regional referral hospitals in Uganda were reviewed for children admitted on selected days between June 2016 and May 2017. Data was extracted on the results, if any, of pre-transfusion hemoglobin (Hb) level, whether or not a blood transfusion was given and inpatient outcome for all children with a diagnosis of 'severe anemia'. Qualitative data was also collected from health workers to explain the reasons for the clinical practices at the two hospitals.

RESULTS

Overall, 574/2275 (25.2%) of the children admitted in the two hospitals were assigned a diagnosis of SA. However 551 (95.9%) of children assigned a diagnosis of SA received a blood transfusion, accounting for 551/560 (98.4%) of the blood transfusions in the pediatric wards. Of the blood transfusions in SA children, only 245 (44.5%) was given appropriately per criteria (Pre-transfusion Hb ≤ 6 g/dL), while 306 (55.5%) was given inappropriately; (pre-transfusion Hb not done, n = 216, or when a transfusion is not indicated [Hb > 6.0 g/dl], n = 90). SA children transfused appropriately per Hb criteria had lower inpatient mortality compared to those transfused inappropriately, (7 (2.9%) vs. 22 (7.2%), [OR 0.4, 95% CI 0.16, 0.90]). Major issues identified by health workers as affecting use of blood transfusion included late presentation of SA children to hospital and unreliable availability of equipment for measurement of Hb.

CONCLUSION

More than half the blood transfusions given in the management of anemic children admitted to Lira and Jinja hospitals was given inappropriately either without pre-transfusion Hb testing or when not indicated. Verification of Hb level by laboratory testing and training of health workers to adhere to transfusion guidelines could result in a substantial decrease in inappropriate blood transfusion in Ugandan hospitals.

Human parvovirus B19-induced anaemia in pre-school children in Ilorin, Nigeria

Sera collected from 57 anaemic and 115 non-anaemic age-matched pre-school children in Ilorin, Nigeria, between November 2014 and December 2015 were assayed for human parvovirus B19-specific IgM antibodies by using the enzyme linked immunosorbent assay technique. A total of 17 (29.8%) anaemic children and 18 (15.7%) non-anaemic children were positive for parvovirus B19 infection. Infection with parvovirus B19 is common in this population, and screening for the virus during differential diagnosis is recommended.

Insecticide-treated nets and malaria prevalence, Papua New Guinea, 2008-2014

Objective

To investigate changes in malaria prevalence in Papua New Guinea after the distribution of long-lasting Insecticide-treated nets, starting in 2004, and the introduction of artemisinin-based combination therapy in 2011.

Methods

Two malaria surveys were conducted in 2010–2011 and 2013–2014. They included 77 and 92 randomly selected villages, respectively. In each village, all members of 30 randomly selected households gave blood samples and were assessed for malaria infection by light microscopy. In addition, data were obtained from a malaria survey performed in 2008–2009.

Results

The prevalence of malaria below 1600 m in altitude decreased from 11.1% (95% confidence interval, CI: 8.5–14.3) in 2008–2009 to 5.1% (95% CI 3.6–7.4) in 2010–2011 and 0.9% (95% CI 0.6–1.5) in 2013–2014. Prevalence decreased with altitude. Plasmodium falciparum was more common than P. vivax overall, but not everywhere, and initially the prevalence of P. vivax infection decreased more slowly than P. falciparum infection. Malaria infections were clustered in households. In contrast to findings in 2008–2009, no significant association between net use and prevalence was found in the later two surveys. The prevalence of both fever and splenomegaly also decreased but their association with malaria infection became stronger.

Conclusion

Large-scale insecticide-treated net distribution was associated with an unprecedented decline in malaria prevalence throughout Papua New Guinea, including epidemic-prone highland areas. The decline was accompanied by broader health benefits, such as decreased morbidity. Better clinical management of nonmalarial fever and research into residual malaria transmission are required.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

Complicated malaria symptoms associated with Plasmodium vivax among patients visiting health facilities in Mendi town, Northwest Ethiopia

BACKGROUND

Malaria is still a major health problem in some parts of the world. Plasmodium falciparum is the common pathogenic parasite and is responsible for majority of malaria associated deaths. Recently the other benign parasite, P. vivax, is reported to cause life threatening severe malaria complications. Thus, this study was aimed to assess incidence of severe malaria symptoms caused by P. vivax parasite in some malaria endemic areas of Ethiopia.

MATERIALS AND METHODS

Presumptive malaria patients (all age groups) seeking medication at the selected health facilities in Mendi town, Northwest Ethiopia, were recruited for the study. Socio-demographic, clinical and parasitological characteristics were assessed following standard procedures. Data was analyzed using descriptive statistics, chi-square test and relative risk.

RESULTS

Of the 384 patients enrolled in the study for P. vivax mono-infection, 55 (14.3 %) of them were fulfilled at least one of the WHO criteria for severe malaria indicators. Some of these clinical manifestations were: prostration 14 (25.45 %), persistent vomiting 9 (16.36 %), respiratory distress 6 (10.9 %), hypoglycemia 5 (9.1 %), hyperpyrexia 8 (14.5 %), and severe anemia 13 (23.63 %). Differences in parasite load did not affect the frequency of some severe malaria symptoms. However, severe anemia, prostration, and persistent vomiting were significantly affected (P < 0.05) by relatively higher load of parasitemia, (OR = 3.8, 95 % CI, 1.1-13.7; OR = 4.4, 95 % CI, 1.4-13.9; and OR = 7, 95 % CI, 1.8-27.4) respectively.

CONCLUSION

P.vivax associated severe malaria symptoms observed in this study is supportive evidence for the notion that P.vivax is no longer benign parasite but rather virulent. Thus, to meet international and regional targets of malaria eradication, a holistic prevention and control approaches should be designed.

Changes in malaria burden and transmission in sentinel sites after the roll-out of long-lasting insecticidal nets in Papua New Guinea

Background

Papua New Guinea exhibits a complex malaria epidemiology due to diversity in malaria parasites, mosquito vectors, human hosts, and their natural environment. Heterogeneities in transmission and burden of malaria at various scales are likely to affect the success of malaria control interventions, and vice-versa. This manuscript assesses changes in malaria prevalence, incidence and transmission in sentinel sites following the first national distribution of long-lasting insecticidal nets (LLINs).

Methods

Before and after the distribution of LLINs, data collection in six purposively selected sentinel sites included clinical surveillance in the local health facility, household surveys and entomological surveys. Not all activities were carried out in all sites. Mosquitoes were collected by human landing catches. Diagnosis of malaria infection in humans was done by rapid diagnostic test, light microscopy and PCR for species confirmation.

Results

Following the roll-out of LLINs, the average monthly malaria incidence rate dropped from 13/1,000 population to 2/1,000 (incidence rate ratio = 0.12; 95 % CI: 0.09–0.17; P < 0.001). The average population prevalence of malaria decreased from 15.7 % pre-LLIN to 4.8 % post-LLIN (adjusted odds ratio = 0.26; 95 % CI: 0.20–0.33; P < 0.001). In general, reductions in incidence and prevalence were more pronounced in infections with P. falciparum than with P. vivax. Additional morbidity indicators (anaemia, splenomegaly, self-reported fever) showed a decreasing trend in most sites. Mean Anopheles man biting rates decreased from 83 bites/person/night pre-LLIN to 31 post-LLIN (P = 0.008). Anopheles species composition differed between sites but everywhere diversity was lower post-LLIN. In two sites, post-LLIN P. vivax infections in anophelines had decreased but P. falciparum infections had increased despite the opposite observation in humans.

Conclusions

LLIN distribution had distinct effects on P. falciparum and P. vivax. Higher resilience of P. vivax may be attributed to relapses from hypnozoites and other biological characteristics favouring the transmission of P. vivax. The effect on vector species composition varied by location which is likely to impact on the effectiveness of LLINs. In-depth and longer-term epidemiological and entomological investigations are required to understand when and where residual transmission occurs and whether observed changes are sustained.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1635-x) contains supplementary material, which is available to authorized users.

Micronutrient Deficiencies and Plasmodium vivax Malaria among Children in the Brazilian Amazon

Background

There is a growing body of evidence linking micronutrient deficiencies and malaria incidence arising mostly from P. falciparum endemic areas. We assessed the impact of micronutrient deficiencies on malaria incidence and vice versa in the Brazilian state of Amazonas.

Methodology/Principal Findings

We evaluated children <10 years old living in rural communities in the state of Amazonas, Brazil, from May 2010 to May 2011. All children were assessed for sociodemographic, anthropometric and laboratory parameters, including vitamin A, beta-carotene, zinc and iron serum levels at the beginning of the study (May 2010) and one year later (May 2011). Children were followed in between using passive surveillance for detection of symptomatic malaria. Those living in the study area at the completion of the observation period were reassessed for micronutrient levels. Univariate Cox-proportional Hazards models were used to assess whether micronutrient deficiencies had an impact on time to first P. vivax malaria episode. We included 95 children median age 4.8 years (interquartile range [IQR]: 2.3–6.6), mostly males (60.0%) and with high maternal illiteracy (72.6%). Vitamin A deficiencies were found in 36% of children, beta-carotene deficiency in 63%, zinc deficiency in 61% and iron deficiency in 51%. Most children (80%) had at least one intestinal parasite. During follow-up, 16 cases of vivax malaria were diagnosed amongst 13 individuals. Micronutrient deficiencies were not associated with increased malaria incidence: vitamin A deficiency [Hazard ratio (HR): 1.51; P-value: 0.45]; beta-carotene [HR: 0.47; P-value: 0.19]; zinc [HR: 1.41; P-value: 0.57] and iron [HR: 2.31; P-value: 0.16]). Upon reevaluation, children with al least one episode of malaria did not present significant changes in micronutrient levels.

Conclusion

Micronutrient serum levels were not associated with a higher malaria incidence nor the malaria episode influenced micronutrient levels. Future studies targeting larger populations to assess micronutrients levels in P. vivax endemic areas are warranted in order to validate these results.

Associação entre malária e anemia em área urbana de transmissão do Plasmodium: Mâncio Lima, Acre, Brasil

Resumo: O objetivo deste trabalho é analisar a prevalência de anemia atribuível à malária na população urbana residente no Município de Mâncio Lima, Acre, Brasil. Trata-se de um estudo de coorte não concorrente com 1.167 pessoas acompanhadas por três meses anteriores à data da entrevista mediante dados do SIVEP-Malária. Foram calculadas as medidas de frequência e a prevalência de anemia em pacientes com e sem histórico de malária recente, conforme as variáveis de interesse. Os resultados mostraram que 50,2% dos indivíduos eram do sexo masculino e 67,96% encontravam-se na faixa etária de 15 anos ou mais. A prevalência geral de anemia foi de 7,1%, sendo maior na faixa etária de 6 meses até 5 anos de idade. Com relação ao histórico de malária recente, verificou-se que 8,3% dos homens que tiveram malária apresentaram anemia. No geral, a prevalência de anemia atribuível à malária foi nulo, exceto para os homens (2,4%) e no bairro Cobal (51,4%). Os resultados demonstram que a prevalência de anemia é baixa e que a contribuição da malária para anemia existe apenas em homens e áreas geográficas específicas.

Prevalence of malaria across Papua New Guinea after initial roll-out of insecticide-treated mosquito nets

OBJECTIVES

To assess the population prevalence of malaria in villages across Papua New Guinea (PNG) following the first roll-out of free long-lasting insecticidal nets (LLIN).

METHODS

Between October 2008 and August 2009, a household survey was conducted in 49 random villages in districts covered by the LLIN distribution campaign. The survey extended to 19 villages in sentinel sites that had not yet been covered by the campaign. In each village, 30 households were randomly sampled, household heads were interviewed and capillary blood samples were collected from all consenting household members for microscopic diagnosis of malaria.

RESULTS

Malaria prevalence ranged from 0% to 49.7% with a weighted average of 12.1% (95% CI 9.5, 15.3) in the national sample. More people were infected with Plasmodium falciparum (7.0%; 95% CI 5.4, 9.1) than with P. vivax (3.8%; 95% CI 2.4, 5.7) or P. malariae (0.3%; 95% CI 0.1, 0.6). Parasitaemia was strongly age-dependent with a P. falciparum peak at age 5-9 years and a P. vivax peak at age 1-4 years, yet with differences between geographical regions. Individual LLIN use and high community coverage were associated with reduced odds of infection (OR = 0.64 and 0.07, respectively; both P < 0.001). Splenomegaly in children and anaemia were common morbidities attributable to malaria.

CONCLUSIONS

Malaria prevalence across PNG is again at levels comparable to the 1970s. The strong association of LLIN use with reduced parasitaemia supports efforts to achieve and maintain high country-wide coverage. P. vivax infections will require special targeted approaches across PNG.

Ultrasonographic assessment of splenic volume at presentation and after anti-malarial therapy in children with malarial anaemia

Background

Splenic enlargement is a component of the host response to malaria and may also influence the genesis and progression of malarial anaemia. Few cross-sectional and no longitudinal studies have assessed the relationship between splenic volume measured ultrasonographically and haemoglobin concentrations in children with malaria.

Methods

Fifteen Papua New Guinean children with severe malarial anaemia (SMA; haemoglobin <50 g/L) and ten with moderate malarial anaemia (MMA; 51–99 g/L) were recruited. The SMA patients were given intramuscular artemether followed by oral artemisinin combination therapy (ACT), and were transfused one unit of packed cells 0.3-4.0 days post-admission. The MMA patients were treated with ACT. Splenic enlargement (Hackett’s grade, subcostal distance and ultrasonographically determined volume) and haemoglobin concentrations were measured on days 0, 1, 2, 3, 7, 14, 28, and 42.

Results

Associations between Hackett’s grade, subcostal distance and splenic volume were modest (r_s ≤ 0.62, P <0.001). Baseline splenic volume was not associated with age or haemoglobin (P ≥0.90). Mean splenic volume had fallen by approximately 50 % at day 14 in children with MMA (P ≤0.011 vs days 0, 1 and 2), but there was no change in the SMA group (P ≥0.30). There was no change in haemoglobin in the MMA group during follow-up but a rise in the SMA group to day 7 (P ≤0.05 vs days 0, 1, 2, and 3) which paralleled the packed cell volume transfused.

Conclusions

Clinical assessment of splenomegaly is imprecise compared with ultrasonography. Serial splenic volumes and haemoglobin concentrations suggest that the spleen does not influence post-treatment haemoglobin, including after transfusion.

Factors Associated with Anemia among Children Aged 6-23 Months Attending Growth Monitoring at Tsitsika Health Center, Wag-Himra Zone, Northeast Ethiopia

Background. Globally, about 47.4% of children under five are suffering from anemia. In Ethiopia, 60.9% of children under two years are suffering from anemia. Anemia during infancy and young childhood period is associated with poor health and impaired cognitive development, leading to reduced academic achievement and earnings potential in their adulthood life. However, there is scarcity of information showing the magnitude of iron deficiency anemia among young children in Ethiopia. Therefore, this study aimed at assessing prevalence and associated factors of iron deficiency anemia among children under two (6-23 months). Methods. Institution based cross-sectional study was carried out from March to May, 2014, at Tsitsika Health Center in Wag-Himra Zone, Northeast Ethiopia. Systematic random sampling technique was employed. Automated hemoglobin machine was used to determine the hemoglobin level. Socioeconomic and demographic data were collected by using a pretested and structured questionnaire. Binary logistic regression analysis was used to identify associated factors and odds ratio with 95% CI was computed to assess the strength of association. Results. Total of 347 children participated in this study. The overall prevalence of anemia was 66.6%. In multivariate logistic regression analysis, male sex (AOR = 3.1 (95% CI: 1.60-5.81)), 9-11 months of age (AOR = 9.6 (95% CI: 3.61-25.47)), poor dietary diversity (AOR = 3.2 (95% CI: 1.35-7.38)), stunting (AOR = 2.7 (95% CI: 1.20-6.05)), diarrhea (AOR = 4.9 (1.63-14.59)), no formal education (AOR = 2.6 (95% CI: 1.26-5.27)), early initiation of complementary food (AOR = 11.1 (95% CI: 4.08-30.31)), and lowest wealth quintile (AOR = 3.0 (95% CI: 1.01-8.88)) were significantly associated with anemia. Conclusion. The overall prevalence of anemia among children who aged 6-23 months has sever public health importance in the study area. Integrated efforts need to be prioritized to improve health as well as appropriate infant and young child feeding practice among children under.

Artemether-lumefantrine versus artemisinin-naphthoquine in Papua New Guinean children with uncomplicated malaria: a six months post-treatment follow-up study

BACKGROUND

In a recent trial of artemisinin-naphthoquine (artemisinin-NQ) and artemether-lumefantrine (AM-LM) therapy in young children from Papua New Guinea (PNG), there were no treatment failures in artemisinin-NQ-treated children with Plasmodium falciparum or Plasmodium vivax compared with 2.2% and 30.0%, respectively, in AM-LM-treated children during 42 days of follow-up. To determine whether, consistent with the long elimination half-life of NQ, this difference in efficacy would be more durable, clinical episodes of malaria were assessed in a subset of trial patients followed for six months post-treatment.

METHODS

For children completing trial procedures and who were assessable at six months, all within-trial and subsequent clinical malaria episodes were ascertained, the latter by clinic attendances and/or review of hand-held health records. Presentations with non-malarial illness were also recorded. Differences between allocated treatments for pre-specified endpoints were determined using Kaplan-Meier survival analysis.

RESULTS

Of 247 children who were followed to Day 42, 176 (71.3%) were included in the present sub-study, 87 allocated to AM-LM and 89 to artemisinin-NQ. Twenty children in the AM-LM group (32.8%) had a first episode of clinical malaria within six months compared with 10 (16.4%) in the artemisinin-NQ group (P = 0.033, log rank test). The median (interquartile range) time to first episode of clinical malaria was 64 (50-146) vs 116 (77-130) days, respectively (P = 0.20). There were no between-group differences in the incidence of first presentation with non-malarial illness (P = 0.31).

CONCLUSIONS

The greater effectiveness of artemisinin-NQ over conventional AM-LM extends to at least six months post-treatment for clinical malaria but not non-malarial illness.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12610000913077 .

Iron prevents the development of experimental cerebral malaria by attenuating CXCR3-mediated T cell chemotaxis

Cerebral malaria is a severe neurological complication of Plasmodium falciparum infection. Previous studies have suggested that iron overload can suppress the generation of a cytotoxic immune response; however, the effect of iron on experimental cerebral malaria (ECM) is yet unknown. Here we determined that the incidence of ECM was markedly reduced in mice treated with iron dextran. Protection was concomitant with a significant decrease in the sequestration of CD4+ and CD8+ T cells within the brain. CD4+ T cells demonstrated markedly decreased CXCR3 expression and had reduced IFNγ-responsiveness, as indicated by mitigated expression of IFNγR2 and T-bet. Additional analysis of the splenic cell populations indicated that parenteral iron supplementation was also associated with a decrease in NK cells and increase in regulatory T cells. Altogether, these results suggest that iron is able to inhibit ECM pathology by attenuating the capacity of T cells to migrate to the brain.

Multiparasitism and intensity of helminth infections in relation to symptoms and nutritional status among children: a cross-sectional study in southern Lao People's Democratic Republic

The occurrence and spatial distribution of intestinal helminth infection in children is fairly well understood. However, knowledge on how helminth infections govern intestinal morbidity is scarce. We conducted a cross-sectional study to assess and quantify the relationship between single and multiple species helminth infection with clinical and self-reported morbidity indicators and nutritional status in Champasack province, southern Lao People's Democratic Republic (Lao PDR). A random sample of 1313 children, aged 6 months to 12 years, from villages in nine rural districts were enrolled and examined for helminth infection using duplicate Kato-Katz thick smears. Morbidity was assessed by self-reported symptoms, coupled with clinical examination and appraisal of nutritional status and anaemia. Bivariate and multivariate logistic regression was employed to study associations between helminth infection and morbidity indicators and anaemia. We found considerable morbidity among the surveyed children, including hepatomegaly (13.7%), pale conjunctiva (13.2%) and abdominal pain (10.4%). Anaemia was recorded in 60.4% of the children, whilst signs of stunting and low body mass index (BMI) were observed in 49.8% and 33.3% of the surveyed children, respectively. Hookworm and Opisthorchis viverrini were the predominant helminth species with prevalences of 51.0% and 43.3%, respectively. The prevalence of Schistosoma mekongi in the surveyed children was 5.6%. Multiple species helminth infections were recorded in 40.4% of the study cohort. Morbidity was associated with specific helminth species infection (e.g. S. mekongi with hepatomegaly; adjusted odds ratio (aOR): 9.49, 95% confidence interval (CI): 2.07-43.51) and multiparasitism (e.g. two or more helminth species with abdominal pain; aOR: 2.40, 95% CI: 1.46-3.93). Anaemia was associated with hookworm infection (aOR: 1.64, 95% CI: 1.16-2.34) and multiparasitism (aOR: 1.64, 95% CI: 1.18-2.29). Low BMI was associated with O. viverrini infection (aOR: 1.68, 95% CI: 1.14-2.49) and multiparasitism (aOR: 1.42, 95% CI: 1.01-2.00). The multiple strong associations reported here between helminth infections (single or multiple species) and intestinal morbidity among children in rural parts of southern Lao PDR call for concerted efforts to control helminth infections, which in turn might improve children's health and development.

Severe vivax malaria: a systematic review and meta-analysis of clinical studies since 1900

BACKGROUND

Malaria caused by Plasmodium vivax was long considered to have a low mortality, but recent reports from some geographical areas suggest that severe and complicated vivax malaria may be more common than previously thought.

METHODS

The primary objective of this systematic review and meta-analysis was to describe the reported clinical characteristics and the geographical variation in prevalence of reported severe vivax malaria and its change over time derived from English-language articles published since 1900. Medline and Scopus databases were searched for original papers on severe vivax malaria, using as inclusion criteria modified 2010 WHO criteria for the diagnosis of severe falciparum malaria. Articles before 1949 were identified through reference lists in journals, textbooks, and personal collections of colleagues.

RESULTS

A total of 77 studies with reported severe vivax malaria and 63 studies with no reported severe vivax malaria (totaling 46,411 and 6,753 vivax malaria patients, respectively) were included. The 77 studies with reported severe vivax malaria were mainly from India (n = 33), USA (n = 8), Indonesia (n = 6), and Pakistan (n = 6). Vivax endemic countries not reporting severe vivax malaria beyond individual case reports included: the Greater Mekong Sub-region, China, North Korea, Bangladesh, Afghanistan, Middle East (except Qatar), the horn of Africa, and Madagascar. Only 17/77 reports were from before 2000. Vivax mono-infection was confirmed by PCR in 14 studies and co-morbidities were ruled out in 23 studies. Among the 77 studies reporting severe vivax malaria, severe thrombocytopenia (<50,000/mm3) was the most common "severe" manifestation (888/45,775 with pooled prevalence of 8.6%). The case fatality was 0.3% (353/46,411). Severity syndromes varied widely between different geographical areas, with severe anaemia being most prominent in areas of high transmission and chloroquine resistance.

CONCLUSION

Plasmodium vivax can cause severe and even fatal disease, but there is a recent increase in reports over the past 15 years with larger series restricted to a limited number of geographical areas. The biological basis of these variations is currently not known. More detailed epidemiological studies are needed which dissociate causation from association to refine the definition and estimate the prevalence of severe vivax malaria.

Prevalence and Severity of Malaria Parasitemia among Children Requiring Emergency Blood Transfusion in a Tertiary Hospital in Imo State, Nigeria

Background:

Malaria is one of the most serious and complex health problems in Sub Saharan Africa. Anemia in Children with malaria may require blood transfusion and has been be associated with high mortality rates.

Aim:

The aim of this study is to evaluate the prevalence, pattern, and severity of malaria parasitemia among children 6 months to 14 years old, requiring blood transfusion.

Subjects and Methods:

This is a cross-sectional study carried out at the children emergency unit of the Imo state University Teaching Hospital South East Nigeria. Data were analyzed using SPSS version 21, Chicago Il, USA

Results:

A total of 409 children were recruited into the study. The overall rate of malaria parasitemia was 83.1% (340/409) lower in males 81.6% (228/276) than in females 86.3% (112/133). The peak of parasitemia is similar in both sexes (5-9 years). Most of the children had medium levels of parasitemia, which decreased with increasing age. The proportion of children transfused also decreased with increasing age. At medium and high levels of parasitemia; in children below 5 years, 92.8% (132/142) were transfused while in 5 years and above only 79.6% (39/49) of the children were transfused. At medium level parasitemia the proportion of children transfused was significantly higher than those not transfused (P < 0.001).

Conclusion:

Most children 6 months to 14 years with medium level of parasitemia may require blood transfusion. Targeted measures toward primary prevention of malaria in children should be intensified as this will not only reduce morbidity and mortality of malaria, but will reduce the economic burden of the disease in Semi-rural and rural dwellers in Sub Saharan Africa.

Is Plasmodium vivax malaria a severe malaria?: a systematic review and meta-analysis

Background

Plasmodium vivax is one of the major species of malaria infecting humans. Although emphasis on P. falciparum is appropriate, the burden of vivax malaria should be given due attention. This study aimed to synthesize the evidence on severe malaria in P. vivax infection compared with that in P. falciparum infection.

Methods/Principal Findings

We searched relevant studies in electronic databases. The main outcomes required for inclusion in the review were mortality, severe malaria (SM) and severe anaemia (SA). The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Overall, 26 studies were included. The main meta-analysis was restricted to the high quality studies. Eight studies (n = 27490) compared the incidence of SM between P. vivax infection and P. falciparum mono-infection; a comparable incidence was found in infants (OR: 0.45, 95% CI:0.04–5.68, I²:98%), under 5 year age group (OR: 2.06, 95% CI: 0.83–5.1, I²:83%), the 5–15 year-age group (OR: 0.6, 95% CI: 0.31–1.16, I²:81%) and adults (OR: 0.83, 95% CI: 0.67–1.03, I²:25%). Six studies reported the incidences of SA in P. vivax infection and P. falciparum mono-infection; a comparable incidence of SA was found among infants (OR: 3.47, 95%:0.64–18.94, I²: 92%), the 5–15 year-age group (OR:0.71, 95% CI: 0.06–8.57, I²:82%). This was significantly lower in adults (OR:0.75, 95% CI: 0.62–0.92, I²:0%). Five studies (n = 71079) compared the mortality rate between vivax malaria and falciparum malaria. A lower rate of mortality was found in infants with vivax malaria (OR:0.61, 95% CI:0.5–0.76, I²:0%), while this was comparable in the 5–15 year- age group (OR: 0.43, 95% CI:0.06–2.91, I²:84%) and the children of unspecified-age group (OR: 0.77, 95% CI:0.59–1.01, I²:0%).

Conclusion

Overall, the present analysis identified that the incidence of SM in patients infected with P. vivax was considerable, indicating that P. vivax is a major cause of SM. Awareness of the clinical manifestations of vivax malaria should prompt early detection. Subsequent treatment and monitoring of complications can be life-saving.

Until recently, vivax malaria has received less attention than falciparum malaria and was deemed neglected. There has been a surge in studies that documented the contribution of Plasmodium vivax to severe malaria in some endemic countries such as Thailand, Brazil, Indonesia, Papua New Guinea and India. We aimed to synthesize the evidence on severe malaria in P. vivax infection compared with that in P. falciparum infection. We searched relevant studies in electronic databases. The combined results of the eight relatively high quality studies showed a comparable incidence between vivax malaria and falciparum malaria in infants, under 5 year age group, the 5–15 year age group and adults. The combined results of the six relatively high quality studies revealed a comparable incidence of severe anaemia between P. vivax infection and P. falciparum mono-infection in both the infants and the 5–15 year age group. Considering that severe malaria and deaths attributable to P. vivax is not a rare event, raised clinical awareness of the manifestations of vivax malaria in patients of any age should prompt early detection of malaria. It is likely that early detection, appropriate treatment commenced in a timely manner and close monitoring of any complications could be life-saving and contribute to the attainment of the global vision of no malaria deaths.

Iron, anemia and hepcidin in malaria

Malaria and iron have a complex but important relationship. Plasmodium proliferation requires iron, both during the clinically silent liver stage of growth and in the disease-associated phase of erythrocyte infection. Precisely how the protozoan acquires its iron from its mammalian host remains unclear, but iron chelators can inhibit pathogen growth in vitro and in animal models. In humans, iron deficiency appears to protect against severe malaria, while iron supplementation increases risks of infection and disease. Malaria itself causes profound disturbances in physiological iron distribution and utilization, through mechanisms that include hemolysis, release of heme, dyserythropoiesis, anemia, deposition of iron in macrophages, and inhibition of dietary iron absorption. These effects have significant consequences. Malarial anemia is a major global health problem, especially in children, that remains incompletely understood and is not straightforward to treat. Furthermore, the changes in iron metabolism during a malaria infection may modulate susceptibility to co-infections. The release of heme and accumulation of iron in granulocytes may explain increased vulnerability to non-typhoidal Salmonella during malaria. The redistribution of iron away from hepatocytes and into macrophages may confer host resistance to superinfection, whereby blood-stage parasitemia prevents the development of a second liver-stage Plasmodium infection in the same organism. Key to understanding the pathophysiology of iron metabolism in malaria is the activity of the iron regulatory hormone hepcidin. Hepcidin is upregulated during blood-stage parasitemia and likely mediates much of the iron redistribution that accompanies disease. Understanding the regulation and role of hepcidin may offer new opportunities to combat malaria and formulate better approaches to treat anemia in the developing world.

Immunobiology of Plasmodium in liver and brain

Malaria remains one of the most serious health problems globally, but our understanding of the biology of the parasite and the pathogenesis of severe disease is still limited. Multiple cellular effector mechanisms that mediate parasite elimination from the liver have been described, but how effector cells use classical granule-mediated cytotoxicity to attack infected hepatocytes and how cytokines and chemokines spread via the unique fluid pathways of the liver to reach the parasites over considerable distances remains unknown. Similarly, a wealth of information on cerebral malaria (CM), one of the most severe manifestations of the disease, was gained from post-mortem analyses of human brain and murine disease models, but the cellular processes that ultimately cause disease are not fully understood. Here, we discuss how imaging of the local dynamics of parasite infection and host response as well as consideration of anatomical and physiological features of liver and brain can provide a better understanding of the initial asymptomatic hepatic phase of the infection and the cascade of events leading to CM. Given the increasing drug resistance of both parasite and vector and the unavailability of a protective vaccine, the urgency to reduce the tremendous morbidity and mortality associated with severe malaria is obvious.

Major burden of severe anemia from non-falciparum malaria species in Southern Papua: a hospital-based surveillance study

BACKGROUND

The burden of anemia attributable to non-falciparum malarias in regions with Plasmodium co-endemicity is poorly documented. We compared the hematological profile of patients with and without malaria in southern Papua, Indonesia.

METHODS AND FINDINGS

Clinical and laboratory data were linked for all patients presenting to a referral hospital between April 2004 and December 2012. Data were available on patient demographics, malaria diagnosis, hemoglobin concentration, and clinical outcome, but other potential causes of anemia could not be identified reliably. Of 922,120 patient episodes (837,989 as outpatients and 84,131 as inpatients), a total of 219,845 (23.8%) were associated with a hemoglobin measurement, of whom 67,696 (30.8%) had malaria. Patients with P. malariae infection had the lowest hemoglobin concentration (n = 1,608, mean = 8.93 [95% CI 8.81-9.06]), followed by those with mixed species infections (n = 8,645, mean = 9.22 [95% CI 9.16-9.28]), P. falciparum (n = 37,554, mean = 9.47 [95% CI 9.44-9.50]), and P. vivax (n = 19,858, mean = 9.53 [95% CI 9.49-9.57]); p-value for all comparisons <0.001. Severe anemia (hemoglobin <5 g/dl) was present in 8,151 (3.7%) patients. Compared to patients without malaria, those with mixed Plasmodium infection were at greatest risk of severe anemia (adjusted odds ratio [AOR] 3.25 [95% CI 2.99-3.54]); AORs for severe anaemia associated with P. falciparum, P. vivax, and P. malariae were 2.11 (95% CI 2.00-2.23), 1.87 (95% CI 1.74-2.01), and 2.18 (95% CI 1.76-2.67), respectively, p<0.001. Overall, 12.2% (95% CI 11.2%-13.3%) of severe anemia was attributable to non-falciparum infections compared with 15.1% (95% CI 13.9%-16.3%) for P. falciparum monoinfections. Patients with severe anemia had an increased risk of death (AOR = 5.80 [95% CI 5.17-6.50]; p<0.001). Not all patients had a hemoglobin measurement, thus limitations of the study include the potential for selection bias, and possible residual confounding in multivariable analyses.

CONCLUSIONS

In Papua P. vivax is the dominant cause of severe anemia in early infancy, mixed P. vivax/P. falciparum infections are associated with a greater hematological impairment than either species alone, and in adulthood P. malariae, although rare, is associated with the lowest hemoglobin concentration. These findings highlight the public health importance of integrated genus-wide malaria control strategies in areas of Plasmodium co-endemicity.

Co-infection of human parvovirus B19 with Plasmodium falciparum contributes to malaria disease severity in Gabonese patients

Background

High seroprevalence of parvovirus B19 (B19V) coinfection with Plasmodium falciparum has been previously reported. However, the impact of B19V-infection on the clinical course of malaria is still elusive. In this study, we investigated the prevalence and clinical significance of B19V co-infection in Gabonese children with malaria.

Methods

B19V prevalence was analyzed in serum samples of 197 Gabonese children with P. falciparum malaria and 85 healthy controls using polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and direct DNA-sequencing.

Results

B19V was detected in 29/282 (10.28%) of Gabonese children. B19V was observed more frequently in P. falciparum malaria patients (14.21%) in comparison to healthy individuals (1.17%) (P<0.001). Notably, the mild-malaria group revealed significantly lower hematocrit levels in B19V/P. falciparum co-infection than in P. falciparum mono-infection (P<0.05). Genetic analysis revealed a predominance of B19V genotype-1 (71.43%) in the studied population. However, B19V-genotype 2 was observed significantly more often in children with severe-malaria than in mild-malaria (P=0.04).

Conclusion

Our findings reveal that B19V-infection is frequent in Gabonese children with P. falciparum malaria and signifies a possible contribution of B19V on the clinical course of malaria in a genotype-dependent manner. B19V co-infection should be considered as a additional diagnostic measure in malaria patients with life threatening anemia.