Increase in oxidized proteins in Theileria sergenti-infected erythrocyte membrane

As a part of the elucidation of the pathogenesis of anemia in Theileria sergenti infection, oxidized-erythrocyte membrane proteins (OEMPs) collected from T. sergenti-infected calves were examined. The amount of OEMPs were seen to increase with the progress of the anemia and showed a maximum value around the crisis period of the infection. The increase of OEMPs coincided with band Nos. 1, 2, 2.1, 3, 4.1, 5, 6, and 7. The majority of them was located at the Triton X-100 un-extractive phase, and was confirmed as cytoskeletal proteins. This evidence indicates the enhancement of erythrocytic oxidation, and suggests that it might be one of the aggravating factors of anemia in T. sergenti infection.

[Severe malaria associated with acute renal insufficiency: apropos of a case]

Renal insufficiency as a complication of severe malaria is a rare pathology. A case was observed in young girl aged 10.5 years following Plasmodium malaria fever. Clinical features included severe anemia, oligo-anuria, and creatinemia of 80 mg/l. The haemoglobin electrophoresis was standard. Under furosemide, the resumption of diuresis was effective nine days later. Renal functions of the child affected by severe Plasmodium malarial fever must always be checked.

Anemia in parasite- and recombinant protein-immunized aotus monkeys infected with Plasmodium falciparum

Plasmodium falciparum-induced anemia was characterized in Aotus monkeys repeatedly immunized by infection with P. falciparum (FVO strain) parasites, then cross-challenged with CAMP strain, or in monkeys receiving blood stage challenges as part of malaria vaccine trials. In 4 studies, 25 (30.5%) of 82 monkeys had at least a 50% reduction in hematocrit; mean day of maximum parasitemia was 12.5, whereas the mean day of minimum hematocrit was 18.8 (P < 0.0009). Decreased hematocrit levels were not associated with reticulocytosis until parasite densities decreased significantly from peak levels. Direct antibody tests to detect IgG and C3d on the surface of erythrocytes were negative. Nonantibody/noncomplement-mediated lysis of uninfected erythrocytes seems to be the principal cause of the anemia, and it also seems that bone marrow suppression and lysis of infected erythrocytes contributed to the anemia. Partial immunity-whether induced by repeated immunization with whole parasites or with vaccine-seems important to the development of anemia.

The role of reduced red cell deformability in the pathogenesis of severe falciparum malaria and its restoration by blood transfusion

As reduced red cell deformability (RCD) can contribute to derangement of the microcirculation, a central feature in the pathogenesis of severe malaria, RCD was measured with a laser diffraction technique in 232 consecutive patients with falciparum malaria on the Kenyan coast, of whom 99 had severe disease. RCD on admission (measured as elongation index [EI] at shear stress = 1.7 Pa) was reduced in proportion with severity of disease (fatal outcome: EI = 0.182 (SD = 0.048), survivors from severe disease: EI = 0.217 (SD = 0.043), uncomplicated malaria: EI = 0.249 (SD = 0.030), healthy controls: EI = 0.268 (SD = 0.022). All but 2 survivors with severe malaria and rigid erythrocytes received a blood transfusion restoring RCD. Reduced RCD may contribute to impaired microcirculatory flow and a fatal outcome in falciparum malaria. RCD can be improved by blood transfusion. Since severely reduced RCD has a strong predictive value for mortality, blood transfusion possibly improves disease outcome not only through its beneficial effect on anaemia but also on RCD.

Plasmodium falciparum variant surface antigen expression varies between isolates causing severe and nonsevere malaria and is modified by acquired immunity

In areas of endemic parasite transmission, protective immunity to Plasmodium falciparum malaria is acquired over several years with numerous disease episodes. Acquisition of Abs to parasite-encoded variant surface Ags (VSA) on the infected erythrocyte membrane is important in the development of immunity, as disease-causing parasites appear to be those not controlled by preexisting VSA-specific Abs. In this work we report that VSA expressed by parasites from young Ghanaian children with P. falciparum malaria were commonly and strongly recognized by plasma Abs from healthy children in the same area, whereas recognition of VSA expressed by parasites from older children was weaker and less frequent. Independent of this, parasites isolated from children with severe malaria (cerebral malaria and severe anemia) were better recognized by VSA-specific plasma Abs than parasites obtained from children with nonsevere disease. This was not due to a higher infection multiplicity in younger patients or in patients with severe disease. Our data suggest that acquisition of VSA-specific Ab responses gradually restricts the VSA repertoire that is compatible with parasite survival in the semi-immune host. This appears to limit the risk of severe disease by discriminating against the expression of VSA likely to cause life-threatening complications, such as cerebral malaria and severe anemia. Such VSA seem to be preferred by parasites infecting a nonimmune host, suggesting that VSA expression and switching are not random, and that the VSA expression pattern is modulated by immunity. This opens the possibility of developing morbidity-reducing vaccines targeting a limited subset of common and particularly virulent VSA.

Malaria in pregnancy in Hodiedah, Republic of Yemen

In the Republic of Yemen, Plasmodium falciparum is the predominant causative agent of malaria and is associated with adverse consequences for pregnant women and their babies. The prevalence and clinical manifestations of malaria among 500 pregnant (260) and non-pregnant (240) women were compared. Clinical examinations, laboratory investigations and a structured questionnaire were used to collect data. The prevalence of malaria was higher among pregnant women (55%) than non-pregnant women (20%). Anaemia was significantly more prevalent among pregnant woman than non-pregnant women and also more prevalent in pregnant women with malaria than non-pregnant women with malaria.

The effect of macrophages on the erythrocyte oxidative damage and the pathogenesis of anemia in Babesia gibsoni-infected dogs with low parasitemia

The role of macrophages in the erythrocyte membrane oxidative damage and the pathogenesis of anemia in Babesia gibsoni-infected dogs with low parasitemia were investigated. Macrophages derived from peripheral blood monocytes (PBM) from B. gibsoni-infected dogs produced significantly higher chemiluminescent responses, indicating the release of reactive oxygen intermediates, than those from non-infected dogs when the cells were subjected to non-specific stimulation with phorbol 12-myristate 13-acetate (PMA) and opsonized zymosan (OZ), or infected dog erythrocyte membranes opsonized with infected dog serum. These results indicate that PBM of B. gibsoni-infected dogs with low parasitemia were highly activated compared to those of non-infected dogs. Furthermore, the membrane lipid peroxidation of normal dog erythrocytes incubated with PBM from B. gibsoni-infected dogs was significantly higher (p<0.05) than that of erythrocytes incubated with PBM from non-infected dogs when the PBM were stimulated with the opsonized membranes. These results suggest that the oxidative damage of erythrocytes observed in B. gibsoni-infected dogs with low parasitemia might be induced, in part, by reactive oxygen species released from the activated PBM. On the other hand, the present study also showed a significant increase (p<0.001) of IgG-bound erythrocytes in B. gibsoni-infected dogs compared with such erythrocytes in non-infected dogs. The increase of IgG-bound erythrocytes in infected dogs might reflect the increase of erythrocytes with oxidative damage induced by the infection with B. gibsoni. The results of the present study suggest that the increase of IgG-bound erythrocytes in the circulation of infected dogs induce a high degree of erythrocyte loss via immunological phagocytosis by activated macrophages, resulting in severe anemia in spite of low parasitemia.

Babesia canis infection in a splenectomized dog

The present report describes a fatal case of non-experimental babesiosis in a splenctomized 3-year-old fox terrier. A very intense parasitaemia including clusters of up to 16 Babesiae and a prominent haemophagocytic activity were the most relevant findings. A marked leukocytosis, thrombocytopenia and regenerative anaemia were observed. Despite prompt treatment with babesiacidal compounds the condition progressed to acute renal failure and resulted in the death of the animal 48 hours after the onset of symptoms.

Hematological and coagulation profiles in dogs experimentally infected with Angiostrongylus vasorum (Baillet, 1866)

Hematological and coagulation profiles were studied in crossbred dogs experimentally infected with Angiostrongylus vasorum. Two groups of five dogs were experimentally inoculated with 50 and 100 third stage infective larvae (L(3)) of A. vasorum per kilogram of body weight. A third group of five uninfected animals was used as control. One sample of 10 ml of blood was collected from each animal on the 10, 20, 30, and 45 days after inoculation (dai) and at 30-day intervals thereafter for the remainder of the 210-day experimental period. The blood sample was used for the complete hemogram and platelet count, as well as measurements of prothrombin time, partial thromboplastin time and factors V and VIII. Anemia was observed in infected dogs, 6 weeks after the infection. The eosinophils presented peaks in four periods after infection. Thrombocytopenia became accentuated on the 72 dai. Decreased prothrombin time activity and increased partial thromboplastin time were observed at the 6 and 9 weeks after infection and decreased of factors VIII and V activities occurred from 4 to 6 weeks after infection. It may be conclude that infection by A. vasorum in dogs may cause a discrete anemia during the acute phase which is probably regenerative. In addition, important hemostatic alterations due to the infection suggest a chronic intravascular consumption coagulopathy.

Plasmodium sex determination and transmission to mosquitoes

In order to be transmitted by their mosquito vector, malaria parasites undergo sexual reproduction, which occurs between specialized male and female parasites (gametes) within the blood meal in the mosquito. Nothing was known about how Plasmodium determines the sex of its gametocytes (gamete precursors), which are produced in the vertebrate host. Recently, erythropoietin, the vertebrate hormone controlling erythropoiesis in response to anaemia, was implicated in Plasmodium sex determination in animal models of malaria. This review examines the available information and addresses the relevance of such a sex determining mechanism for Plasmodium falciparum transmission to mosquitoes, with special reference to low gametocytaemias.

An investigation of symptomatic malaria parasitaemia and anaemia in nursery and primary school children in Buea District Cameroon

OBJECTIVES

To investigate the prevalence of asymptomatic malaria parasitaemia and anemia in nursery and primary school children and correlate parasite density with haemoglobin levels.

DESIGN

Cross sectional study.

SETTING

Samples were collected from children attending the Saint Theresa's bilingual school and the Government Primary school, Buea, South West Province, Cameroon.

SUBJECTS

297 nursery and primary school children two to 11 years old selected based on parental consent. MAIN OUTOME MEASURES: Relationship between asymptomatic malaria and anaemia.

RESULTS

The prevalence of asymptomatic malaria in children was 30.3%. Parasite prevalence and density was independent of age and sex (p > 0.05). The mean haemoglobin level for parasitaemic children was 11.9 g/dl (+/- SD1.1) compared with 12.1 g/dl (+/- 1.2) for non-parasitaemic children. The difference was not significant (t = 1.918, p > 0.05). Anaemia when present was mild. No correlation was found between malaria parasite density and haemoglobin levels (r = -0.065; p > 0.05).

CONCLUSION

Asymptomatic malaria was accompanied by low grade parasitaemia, which did not seem to have a significant effect on haemoglobin levels.

Anemia and interleukin-10, tumor necrosis factor alpha, and erythropoietin levels among children with acute, uncomplicated Plasmodium falciparum malaria

Anemia is an important complication of malaria, and its pathogenesis is not well understood. To gain insight into potential age-related relationships between tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), erythropoietin, and anemia during acute malaria, 273 children of ages 12 to 120 months presenting with acute, uncomplicated malaria in Kampala, Uganda, were monitored at enrollment and 3 and 7 days later. Younger children had higher geometric mean erythropoietin, TNF-alpha, and alpha(1)-acid glycoprotein (AGP) concentrations than older children. Univariate regression analysis revealed that age, log(10) erythropoietin levels, IL-10/TNF-alpha ratio, and AGP levels were each significantly associated with hemoglobin levels at baseline. Hemoglobin concentrations were inversely correlated with the log(10) erythropoietin level at all three visits. For the older age groups, higher levels of TNF-alpha were significantly associated with higher IL-10 levels at all three visits, but this relationship was significant only at baseline for younger children. These data suggest that younger children do not maintain IL-10 production in response to the inflammatory process, and this mechanism may contribute to the more severe anemia found in younger children. Acute malaria is an illness whose incidence and severity are largely age dependent. Further studies are needed to understand the relationships between age-related immune responses to malaria and their role in the pathogenesis of malarial anemia.

[Anemia, eosinophilia and generalized weakness in a 20-year old African]

CASE HISTORY AND DIAGNOSIS

A 20-year-old African man was admitted to hospital with anemia, eosinophilia, raised liver enzymes and hepatosplenomegaly. Previously, on arrival in Germany, he had undergone a routine medical check-up where simple microscopy of a feces sample as well as serology for lues, AIDS and hepatitis B had all been negative. In our hospital a stool specimen was examined for ova and parasites and revealed ova of Schistosoma mansoni and confirmed the diagnosis of bilharziosis. For the detection of helmintic ova repeated stool examinations with use of concentration techniques are required. Staging by endoscopies, ultrasonography revealed colon pseudopolyposis and periportal fibrosis complicated by portal hypertension and esophageal varices.

TREATMENT AND COURSE

Chemotherapy with Praziquantel was effective in eliminating the parasites but in advanced stages chronic fibrotic changes are usually irreversible. Further monitoring will therefore be necessary in our patient.

CONCLUSION

Due to increasing migration and international travel, also doctors working in industrialized countries should be aware of tropical diseases.

Clinical evaluation of anaemia in sheep: early trials

Trials were conducted on a farm in Mpumalanga Province in South Africa to test the possibility of grading the colour of the ocular mucous membranes of sheep as an indication of the extent to which the animals are affected by Haemonchus contortus infection. The range of observed colour shades were classified into five categories, from red, through red-pink, pink and pink-white to white. Over a period of 125 days routine drenching of a flock of 388 sheep on irrigated kikuyu (Pennisetum clandestinum) pasture was terminated. During this time the animals were examined at practically weekly intervals and haematocrit determinations done for all the sheep with pale conjunctivae. Only those sheep having a haematocrit of 15% or lower were treated. Compared to a previous drenching tempo of close to every 3 weeks during the Haemonchus season on the farm, drenching was reduced by approximately 90%, as 70% of the sheep did not require salvage drenching and only 10% of the flock had to be given more than one salvage treatment. At the time of the trial the five clinical classifications were not related to predetermined haematocrit categories. However, when compared to categories that were set in later trials, 94% of the clinical estimates in the present trial were either in the correct haematocrit category, or, if not, the sheep were probably not disadvantaged by the errors. In 2.6% of cases the incorrect estimate may have placed the sheep concerned in jeopardy, as the haematocrit values were so low that salvage drenching was required, while the sheep were not regarded as anaemic. Changes in the mean haematocrit values of drenched and undrenched sheep were mirrored reciprocally by the changes in clinical colour estimates. Lactating ewes were by far the most susceptible class of sheep, as only 44.6% of them were able to manage without drenching, compared to 83% of dry, and 70.6% of pregnant ewes. Correlations between the haematocrits and clinical estimates were highly significant, although the associations were not high enough to give reasonable surety that the haematocrit values of individual animals could be predicted with confidence from their clinical classifications. Exceptionally large numbers of worms were recovered from seven of the 14 sheep that were culled because of age at the end of the trial, but these were reflected neither in their faecal worm egg counts, nor, with one exception only, in clinical signs.

Use of clinical judgement to guide administration of blood transfusions in Malawi

The aim of this study was to investigate whether clinicians in Malawi could use clinical judgement alone to administer blood transfusions in accordance with guidelines. Clinicians at a district hospital did not use the Lovibond Comparator haemoglobin results provided by their laboratory as they felt them to be unreliable, preferring instead to rely on their clinical judgement alone to guide transfusion practice. Their transfusion practice and the Lovibond haemoglobin results were monitored against the World Health Organization recommended haemiglobincyanide method for haemoglobin measurement without the clinicians having access to this result. The Lovibond Comparator method was shown to have a sensitivity of only 21% to detect trigger haemoglobin values for transfusion published in local guidelines. Without access to a useful haemoglobin result, clinicians gave 67% of transfusions in accordance with the haemoglobin trigger values in the guidelines. This study shows that clinical features alone can provide a reasonable guide about the need for transfusion, and that poor quality laboratory tests limit the effectiveness of transfusion guidelines.

Spread of Neoheterobothrium hirame (Monogenea), a serious pest of olive flounder Paralichthys olivaceus, to Korea

Neoheterobothrium hirame is a large, blood-feeding gill-worm infecting the highly prized olive flounder Paralichthys olivaceus in Japan. There is strong evidence that this worm is the primary cause of anaemia, a common and serious condition causing losses among both wild and cultured olive flounders. N. hirame was first detected in Japanese waters less than a decade ago, and its population then proliferated and spread throughout most of Japan, except Hokkaido. In neighbouring Korea, olive flounder is the most important species of cultured marine fish, and production currently exceeds that in Japan. However, until now, there have been no reports of any monogeneans or anaemia among olive flounders in Korea. Our survey conducted in 2000 of 100 cultured individuals from 4 provinces revealed 2 immature specimens of N. hirame: 1 from a land-based pond-culture system in southern Cheju Island (off the SW coast of Korea) and the other from a floating net cage near Yosu (in the mid-S part of the peninsula). The geographic range of this pathogen may have been enlarged as a result of introduction(s) of infected broodstock from Japan, but this seems unlikely. (The raising of this species in hatcheries developed in Korea in 1985, 7 years before the earliest detection of the worm in Japan.) Low numbers of flounders were also clearly anaemic. This, and the current rarity of N. hirame in Korean farms, appears to favour the hypothesis of a more recent, natural dispersal of the worm, during migrations of infected flounder across the narrow and shallow Tsushima and Korea Straits. Regardless of route of entry, we expect this pathogen will have an impact on Korean flounder fisheries equally serious to that being experienced in Japan.

Oxidative stress and erythrocyte damage in Kenyan children with severe Plasmodium falciparum malaria

Anaemia causes significant morbidity in children with Plasmodium falciparum malaria, but the mechanism(s) are unclear. During malarial infection, increased reactive oxygen species (ROS) are generated that may contribute to erythrocyte damage and anaemia. This study measured the concentrations of alpha-tocopherol in plasma and erythrocyte membranes, and the percentage polyunsaturated fatty acid composition (%PUFA) (an indirect marker of ROS damage) in erythrocyte membranes in children with severe P. falciparum malaria from Kilifi, Kenya, and asymptomatic children from the same district. Malarial subjects were stratified into complicated malaria and malaria anaemia. Results demonstrated significant reductions in erythrocyte membrane alpha-tocopherol concentration (1.63 +/- 0.16 versus 3.38 +/- 0.18 micromol/mg protein; P < 0.001) and total %PUFA (30.7 +/- 0.49 versus 32.8 +/- 0.44% P < 0.005) for the malarial subjects (non-stratified) compared with controls. Malarial subjects showed a significant positive correlation between membrane alpha-tocopherol and haemoglobin concentrations (P < 0.005 r = 0.63 complicated malaria group; P < 0.05 r = 0.36 non-stratified data). There were no significant differences in plasma alpha-tocopherol concentration between malaria patients and controls. In conclusion, malarial infection may be associated with oxidative damage and reduced alpha-tocopherol reserve in the erythrocyte membrane, suggesting that local antioxidant depletion may contribute to erythrocyte loss in severe malaria. Erythrocyte membrane alpha-tocopherol appeared a better indicator of ROS exposure than plasma.

[Secular trends in childhood in the city of São Paulo, Brazil (1984-1996)]

OBJECTIVE

Data from two consecutive households surveys undertaken in mid-80s and mid-90s allow to characterize and analyse secular trends in infant and child anaemia in the city of S. Paulo, Brazil.

METHODS

The two surveys included random population samples aged from zero to 59 months (1,016 in the period of 1984-85 and 1,280 in 1995-96). Capillary blood samples, collected by digital puncture in the two surveys, were analysed regarding their haemoglobin concentration. The anaemic status was determined when haemoglobin concentration was below 11 g/dL. For each survey, the study of the social distribution of child anaemia took into account tertiles of the per capita family income. For the study of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied.

RESULTS/CONCLUSIONS

In the time span from the first to the second survey, there was a significant reduction in the average haemoglobin concentration (from 11.6 g/dl to 11.0 g/dl), as well as a considerable increase in anaemia prevalence (from 35.6% to 46.9%). Unfavourable trends were observed in both sexes, all age groups and all income strata. Trends were still less favourable among the poorest families, aggravating the social burden related to child anaemia. Changes in distal (family income and maternal schooling) and proximal determinants (breast or bottle-feeding) of child anaemia were positive in the study period and therefore they cannot explain the increase in the disease. A low iron diet could explain the high prevalence of anaemia in both surveys but could not explain its further increase.

Life-threatening severe malarial anaemia

Despite our improved understanding of the pathophysiology of severe malaria, major changes in clinical management have not been forthcoming. However, in the case of life-threatening severe malarial anaemia, preliminary evidence suggests that changes in current clinical practice rather than the introduction of novel interventions may improve child survival. This review argues that further research into the clinical physiology of this syndrome is required and could provide compelling evidence for changes in practice particularly with regard to blood transfusion. We focus on the syndrome of severe, symptomatic malarial anaemia associated with a metabolic acidosis which has a high fatality rate. However, it should be remembered that a far greater number of children without signs of life-threatening disease nonetheless experience significant morbidity from severe anaemia. Many of these less-severely ill children may also require blood transfusion. However, the mode and rationale for transfusion in this less-severely ill group is specifically not addressed. Indeed, the arguments presented should not be extrapolated to suggest a uniform approach to transfusion is warranted, the role of blood in the less-critically ill child with severe malaria anaemia being a further area that requires urgent research.

Prevalence of anaemia and worm infestation in tribal areas of Madhya Pradesh

The study was conducted among school going children (6-14 years) of Baiga, Abuihmadia and Bharia tribes of Madhya Pradesh to assess the prevalence of anaemia and intestinal parasitic infestation among themselves. A total of 776 school going children were included in the study of whom blood samples of all and stool samples of 409 were collected. Their haemoglobin was measured and stool samples were examined under microscope for ova and cysts. The results revealed that 30.3% of the children had severe anaemia (Hb < 7g/dl) and 50% children had intestinal parasites. The most common parasites were hookworn (16.3%) and A lumbricoides (18.5%). Though hookworm ova loads indicated mild to moderate infestation in most of the children, the continued presence of worms in marginally nourished children could contribute significantly to blood loss in the intestine with resultant anaemia.