In malaria-endemic areas, by young adulthood people have developed functional immunity to malaria. However, during pregnancy this immunity is breached and infection occurs, leading to increased risks for mother and child. In the past this effect has been attributed to nonspecific immunosuppression, but recent research has revealed a specific pathogenic mechanism, involving the adherence of rare parasite variants to the placenta. This commentary explores the current state of research in this area and proposes a model of immune evasion and placental colonization. This model points the way to the development of future therapeutic interventions.
Female ; Humans ; Malaria, Falciparum - immunology ; Pregnancy ; Pregnancy Complications ; Parasitic - immunology

Female ; Humans ; Infant, Newborn ; Infectious Disease Transmission, Vertical ; Malaria ; congenital ; diagnosis ; transmission ; Pregnancy ; Pregnancy Complications, Parasitic

This study determined the prevalence of intestinal parasitic infections and associations with risk factors among pregnant women in their second or third trimester in Goroka, Eastern Highlands Province, Papua New Guinea. Among the 201 pregnant women enrolled in this study, 163 (81%) were infected with one or more intestinal parasites. Infections with protozoan parasites (65%) were more prevalent than infections with nematodes (31%); protozoan infections included Entamoeba histolytica (43%), Giardia lamblia (39%) and Pentatrichomonas hominis (14%), and nematode infections included hookworm (18%), Ascaris lumbricoides (14%), Strongyloides stercoralis (3%) and Trichuris trichiura (2%). Factors associated with higher risk of intestinal parasitic infections in pregnancy included being a primigravida for protozoan-only infections and education limited to primary school for nematode infections. Altitude-adjusted haemoglobin levels were assessed at the beginning of labour for 110 women, with 69 (63%) found to be anaemic (haemoglobin < 11 g/dl). There were no associations found between being infected in pregnancy and anaemia.
Adult ; Anemia/*epidemiology ; Feces/parasitology ; Female ; Humans ; Intestinal Diseases, Parasitic/*epidemiology ; Papua New Guinea/epidemiology ; Pregnancy ; Pregnancy Complications, Parasitic/*epidemiology ; Prevalence ; Risk Factors ; Surveys and Questionnaires

The sequestration of infected erythrocytes in the placenta can activate the syncytiotrophoblast to release cytokines that affect the micro-environment and influence the delivery of nutrients and oxygen to fetus. The high level of IL-10 has been reported in the intervillous space and could prevent the pathological effects. There is still no data of Th17 involvement in the pathogenesis of placental malaria. This study was conducted to reveal the influence of placental IL-17 and IL-10 levels on fetal weights in malaria placenta. Seventeen pregnant BALB/C mice were divided into control (8 pregnant mice) and treatment group (9 pregnant mice infected by Plasmodium berghei). Placental specimens stained with hematoxylin and eosin were examined to determine the level of cytoadherence by counting the infected erythrocytes in the intervillous space of placenta. Levels of IL-17 and IL-10 in the placenta were measured using ELISA. All fetuses were weighed by analytical balance. Statistical analysis using Structural Equation Modeling showed that cytoadherence caused an increased level of placental IL-17 and a decreased level of placental IL-10. Cytoadherence also caused low fetal weight. The increased level of placental IL-17 caused low fetal weight, and interestingly low fetal weight was caused by a decrease of placental IL-10. It can be concluded that low fetal weight in placental malaria is directly caused by sequestration of the parasites and indirectly by the local imbalance of IL-17 and IL-10 levels.
Animals ; Female ; *Fetal Weight ; Humans ; Interleukin-10/*analysis/metabolism ; Interleukin-17/*analysis/metabolism ; Malaria/*metabolism/parasitology/physiopathology ; Male ; Mice ; Mice, Inbred BALB C ; Placenta/*chemistry/metabolism ; Plasmodium berghei/*physiology ; Pregnancy ; Pregnancy Complications, Parasitic/*metabolism/parasitology/physiopathology

Toxoplasma gondii is one of the major agents of infectious abortions and due to its worldwide distribution can threat healthy pregnant women who had no previous exposure to this parasite. The present study was designed to investigate the contribution of T. gondii to spontaneous abortions in Zanjan, Northwest of Iran, using ELISA method. Blood Samples were collected from 264 mothers referred to the provincial hospitals of Zanjan due to spontaneous abortion. The sera were isolated and subjected to evaluate the anti-Toxoplasma IgG, IgM and IgA antibodies. The results showed IgG positive (IgG+) in 99 cases (37.5%). A total of 68 women (25.8%) showed seroconversion with IgM or IgA or both IgM and IgA. They included: IgM+ in 21 (8.0%), IgA+ in 23 (8.7%) and both IgM+ and IgA+ in 24 (9.1%) subjects. In 23 cases, positive titers of IgM and IgG were accompanied. In general, the analysis of anti-Toxoplasma antibody patterns, showed that about 17% of the spontaneous abortions were associated with serological patterns of acute infection. According to these findings, a considerable proportion of spontaneous abortions can be attributed to T. gondii in the study area.
Abortion, Spontaneous/immunology/*parasitology ; Antibodies, Protozoan/*blood ; Cross-Sectional Studies ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunoglobulin A/blood ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Iran/epidemiology ; Mothers ; Pregnancy ; Pregnancy Complications, Parasitic/*immunology/parasitology ; Toxoplasma/*immunology ; Toxoplasmosis, Congenital/*immunology/parasitology

The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.
Adult ; Antibodies, Protozoan/*analysis/blood ; Blotting, Western/*methods ; Female ; Fluorescent Antibody Technique/*methods ; Humans ; Immunoenzyme Techniques/*methods ; Immunoglobulin M/*analysis/blood ; Pregnancy ; Pregnancy Complications, Parasitic/blood/*diagnosis ; Toxoplasmosis/blood/*diagnosis ; Young Adult

OBJECTIVETo determine the seroprevalence of toxoplasmosis in pregnant women, as well as the proportion of acutely infected and risk factors in the Democratic Republic of Congo.

METHODSThirty maternities in Kinshasa were randomly selected and women attending antenatal consultation were invited to participate. They were interviewed with a structured questionnaire about known risk factors (age, meat consumption, contact with soil, and presence of cat) and a venous blood sample was taken. Sera were analysed for total immunoglobulins (Ig) by VIDAS Toxo Competition using Enzyme Linked Fluorescent Assay. IgM was determined by VIDIA Toxo IgM and IgG avidity by VIDAS Toxo IgG avidity.

RESULTSA total of 781 women were included. Median age was 28 years old (IQR: 8.5). And 627 women (80.3%; 95% CI: 77.5-83.1) were found to be positive to total Ig and 17 out of 387 (4.4%; 95% CI: 2.3-6.4) were positive to IgM. IgG avidity was low for 2 (11.8%) women, intermediate for 2 (11.8%) and high for 13 women (76.4%). There was no statistically significant association between Toxoplasma gondii infection and any risk factors assessed.

CONCLUSIONIn Kinshasa, toxoplasmosis endemicity is highly prevalent. One woman out of twenty five had a recent toxoplasmosis infection and 20% were not protected against primo-infection, indicating a need for measures to prevent and control toxoplasmosis during pregnancy.

Adolescent ; Adult ; Antibodies, Protozoan ; blood ; Cross-Sectional Studies ; Democratic Republic of the Congo ; epidemiology ; Female ; Humans ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Middle Aged ; Pregnancy ; Pregnancy Complications, Parasitic ; blood ; epidemiology ; Risk Factors ; Seroepidemiologic Studies ; Toxoplasmosis ; blood ; epidemiology ; Young Adult

In Nigeria, malaria causes up to 11% of maternal mortality. Our main aim was to find out the most common mosquito control measures employed by the pregnant women in Lagos and their effects on malaria infection. The study was carried out over a period of 6 months during which trained interviewers administered questionnaires to 400 pregnant women. The prevalence of malaria was 8.4%. There was no significant association between the prevalence of malaria and age, level of education, or occupation of the participants. Pregnant women in the age range 26-30 had the mean parasite density (409.9+/-196.80). Insecticide spray (32.8%), mosquito coil (27.5%), and insecticide-treated nets (ITN) (15.5%) were the major mosquito control measures employed by the participants while the prevalence of infection among them were 2.3%, 6.2%, and 3.2%, respectively (P<0.05). Only 18.3% of the women had taken more than one dose of intermittent preventive treatment (IPT), while another 11.8% had taken a single dose. The infection rate among them was 4.1% and 6.4%, respectively. Malaria prevalence was highest among those who had not received any dose of IPT (10%). This study showed that the use of ITN and IPT among the pregnant women were still unacceptably low. It also showed that the use of insecticide spray which was the most common malaria control measure adopted by the participants was effective despite the fact that it is not a National Malaria Control Policy. We recommend that a sustained integrated mosquito management and public education should be strengthened in Nigeria.
Adolescent ; Adult ; Animals ; *Culicidae/parasitology ; Female ; Health Knowledge, Attitudes, Practice ; Humans ; *Insect Vectors/parasitology ; Insecticides ; Malaria/epidemiology/*prevention & control ; Mosquito Control/*methods ; Nigeria/epidemiology ; Plasmodium/*physiology ; Pregnancy ; Pregnancy Complications, Parasitic/epidemiology/*prevention & control ; Prenatal Care ; Prevalence ; Public Health ; Questionnaires ; Young Adult