Toxoplasmic retinochoroiditis presenting in childhood: clinical findings in a UK survey

AIM

To compare the clinical findings in children with symptomatic toxoplasmic ocular lesions attributable to infection acquired before or after birth.

METHODS

Cases were prospectively ascertained for 24 months through national surveillance units and reference laboratories in the British Isles. Age and presenting symptoms, site of lesion and visual impairment in children who were classified as acquiring infection either before or after birth on the basis of clinical and serological findings were compared.

RESULTS

31 children had toxoplasmic retinochoroiditis, 15 had congenital infection and all but three of these presented before the age of 4 years. The remaining 16 children acquired toxoplasmosis postnatally, and 14 of 16 presented after the age of 10 years. A further four children had retinochoroiditis due to other causes. The presence of bilateral, multiple or posterior pole lesions did not distinguish between the two groups, but most children (16/19; 84%) presenting with acute ocular symptoms had postnatally acquired infection. Unilateral visual impairment (Snellen < or =6/18) was equally prevalent in the two groups (4/9 before birth v 7/16 after birth; p>0.5). Only two children had bilateral visual impairment, both of whom had congenital infection. No child was blind.

CONCLUSIONS

About 50% of children with ocular lesions due to toxoplasmosis had postnatal infection. Retinochoroidal lesions due to infection before and after birth were indistinguishable. The prognosis for bilateral visual function was good, regardless of when infection was acquired.

Congenital malaria in Thailand, an appraisal of previous cases

BACKGROUND

Malaria is an important vector-borne infectious disease. Many tropical countries are the endemic area of malaria. Thailand, a tropical country in Southeast Asia, is the well-known endemic area for malaria. Although Thailand has a high prevalence of malaria, few cases of congenital malaria were reported in the past.

METHODS

Here, the author performed a literature review of the reports of congenital malaria in Thailand in order to summarize the characteristics of this infection among Thai patients.

RESULTS

According to this study, there have been at least six reports in the literature of 27 cases of congenital malaria infection in the Thai population, of which no case was lethal. There were 22 vivax (81.5%) and five falciparum (18.5%) malarial cases. The details on clinical presentations of these cases are presented and discussed.

CONCLUSION

According to this study, it can be seen that congenital malaria may occur in the absence of clinical symptoms in mothers as well as their children. Concerning the species of malaria, the vivax malaria is more common in this case series.

Microscopic and sub-microscopic Plasmodium falciparum infection, but not inflammation caused by infection, is associated with low birth weight

Pregnancy-associated malaria is one of the leading causes of low birth weight in malaria endemic areas. In this study, 145 parturient women residing in areas endemic for Plasmodium falciparum in Lambaréné, Gabon, were recruited into the study after delivery, and the association of maternal P. falciparum infection, inflammatory response, and birth weight was studied. At delivery, 10% (15) of the mothers (12 were positive in both peripheral and placental blood smears, 1 was positive in peripheral blood only, and 2 were positive in placenta blood only) were positive for P. falciparum by microscopy and 23% (30) by real-time polymerase chain reaction (PCR). The level of C-reactive protein (CRP) was significantly elevated in microscopically P. falciparum-positive pregnant women (34 mg/L; 95% CI: 3-458) but not in those with sub-microscopic infections (6 mg/L; 95% CI: 1-40) compared with those free of P. falciparum infection (7 mg/L; 95% CI: 1-43). In a multivariate analysis, the presence of microscopic (adjusted OR = 28.6, 95% CI = 4.8-169.0) or sub-microscopic (adjusted OR = 13.2, 95% CI = 2.4-73.0) P. falciparum infection in pregnant women and age of mothers < 21 years (adjusted OR = 9.7 CI = 1.0-89.7), but not CRP levels, were independent predictors for low birth weight. This finding may have important operational implications and emphasizes the need for appropriate diagnostic methods in studies evaluating the outcome of pregnancy-associated malaria.

Serological and Parasitological Screening of Trypanosoma cruzi Infection in Mothers and Newborns Living in Two Chagasic Areas of Mexico

BACKGROUND

Maternal-fetal transmission of Trypanosoma cruzi generally occurs in 2-12% of pregnant infected mothers. This transmission form has been poorly studied in Mexico where only one case of congenital infection published in 1998 has been reported.

METHODS

We screened 145 mothers and their delivered babies in two hospitals of endemic regions in Mexico (states of Chiapas and Veracruz) searching for anti-T. cruzi antibodies and circulating parasites by hemoculture and PCR.

RESULTS

In Poza Rica, Veracruz, 3/85 (3.5%) mothers were seropositive for T. cruzi infection and in Palenque, Chiapas, 3/60 (5%) cases. In total 6/145 (4.1%) were seropositive subjects. Although cord blood samples of delivered babies from seropositive mothers have IgG anti-T. cruzi antibodies, none presented PCR and positive hemoculture.

CONCLUSIONS

Although a high relative seroprevalence of T. cruzi infection in pregnant women was detected, no case of vertical transmission was recognized. Undoubtedly, further studies of large samples are necessary to evaluate maternal transmission risk in Mexico.

Murine malaria infection induces fetal loss associated with accumulation of Plasmodium chabaudi AS-infected erythrocytes in the placenta

Malarial infection in nonimmune women is a risk factor for pregnancy loss, but the role that maternal antimalarial immune responses play in fetal compromise is not clear. We conducted longitudinal and serial sacrifice studies to examine the pathogenesis of malaria during pregnancy using the Plasmodium chabaudi AS/C57BL/6 mouse model. Peak parasitemia following inoculation with 1,000 parasite-infected murine erythrocytes and survival were similar in infected pregnant and nonpregnant mice, although development of parasitemia and anemia was slightly accelerated in pregnant mice. Importantly, pregnant mice failed to maintain viable pregnancies, most aborting before day 12 of gestation. At abortion, maternal placental blood parasitemia was statistically significantly higher than peripheral parasitemia. Infected mice had similar increases in spleen size and cellularity which were statistically significantly higher than in uninfected mice. In contrast, splenocyte proliferation in response to mitogenic stimulation around peak parasitemia was statistically significantly reduced in both groups of infected mice compared to uninfected, nonpregnant mice, suggesting that lymphoproliferation is not a good indicator of the antimalarial immune responses in pregnant or nonpregnant animals. This study suggests that while pregnant and nonpregnant C57BL/6 mice are equally capable of mounting an effective immune response to and surviving P. chabaudi AS infection, pregnant mice cannot produce viable pups. Fetal loss appears to be associated with placental accumulation of infected erythrocytes. Further study is required to determine to what extent maternal antimalarial immune responses, anemia, and placental accumulation of parasites contribute to compromised pregnancy in this model.

Humoral immune reaction of newborn calves congenitally infected with Neospora caninum and experimentally treated with toltrazuril

Neospora caninum is widely recognized as one of the most important infectious organisms causing abortion and stillbirth in cattle. This parasite causes severe economical losses worldwide. Infection is mostly passed vertically from mother to calf during pregnancy. Under certain circumstances, an infection can lead to abortion, but in most cases it results in a chronically infected calf, which itself will represent the next endogenously infectious generation. So far, no reliable therapeutic or metaphylactic tool has been developed. One possibility to control the problem may consist of treating newborn calves that became vertically infected by a persistently infected mother. This may allow parasite-free offspring. The aim of the present study was to address the questions: (1) can serology be used to assess efficiency of treatment in toltrazuril-medicated animals? and (2) is a strategic prevention measure possible by means of producing N. caninum-free calves from positive cows? Calves from Neospora-seropositive cows and heifers were randomly split into two different medication groups: 36 calves were medicated with toltrazuril and 36 calves obtained a placebo. Medication (20 mg toltrazuril per kg bw) was administered three times, every second day, within the 7 days post natum. Three months after medication, there was no difference in antibody reactivity between the two groups. At later time points (4-6 months), however, significant differences were found, as explained by a strong humoral immunity after chemotherapeutical affection of parasites, while the placebo-treated animals only responded weakly to the persistent infection. In summary, we concluded that (1) serology was not an entirely appropriate tool to answer our initial question and (2) toltrazuril has the potential to eliminate N. caninum in newborn calves. As a consequence, we plan to follow up toltrazuril-medicated calves clinically and serologically over a longer period and investigate if they give birth to Neospora-free calves.

Pregnancy outcomes in women with or without placental malaria infection

OBJECTIVE

To assess delivery outcomes in women with placental malaria who presented at public hospitals in Kisumu, a holoendemic region in western Kenya.

METHODS

A cross-sectional study using both histology and molecular biology was conducted with 90 consecutive pregnant women who presented at 3 hospitals during a 2-week period. Data collectors completed standardized questionnaires using each patient's hospital record and physical examination results, and registered birth indices such as weight, head circumference, and weight-head ratio. Malaria infection of the placenta was assessed using a molecular biology approach (for genomic differences among parasite species) as well as histology techniques. Of the 5 histologic classes of placental infection, class 1 corresponds to active infection and class 4 to past infection; class 2 and 3 to active chronic infection; and class 5 to uninfected individuals. Plasmodium species typing was determined by polymerase chain reaction amplification of the parasite's genome.

RESULTS

In newborns at term, low birth weight was directly associated with classes 2 and 4 of placental infection (P = 0.053 and P = 0.003, respectively), and differences in birth weight remained significant between the 5 classes (P < 0.001) even after adjusting for parity and mother's age. Plasmodium falciparum was the only detected parasite.

CONCLUSIONS

In Kisumu, infection with P. falciparum is an important cause of low birth weight and morbidity when it is associated with histologic classes 2 and 4 of placental infection. Moreover, polymerase chain reaction assays should be supported by ministries of health as an ancillary method of collecting data for malaria control during pregnancy and providing a baseline for future interventions.

Precolostral serology in calves born from Neospora-seropositive mothers

The present study was designed to exploratively determine (a) how many healthy calves, born from seropositive mothers, were also precolostrally seropositive; (b) how many precolostrally negative calves became postcolostrally positive; and (c) in these calves, how the IgG1/IgG2 situation developed pre- and postcolostrally. All calves were born from mothers that were determined to be seropositive in a conventional Neospora caninum-ELISA and by immunoblotting. When the diagnostic performance of the conventional ELISA was compared with that of immunoblotting and an IgG1/IgG2-ELISA in the calves, the latter two exhibited a higher sensitivity: From a total of 15 precolostral calf sera, 7 were positive in the conventional ELISA (diagnostic sensitivity 47%) compared to 15 that were positive by immunoblotting (diagnostic sensitivity 100%) and 12 that were positive by the IgG1/IgG2-ELISA (diagnostic sensitivity 80%). With regard to IgG1/IgG2 findings in the dams, IgG2 appeared as the dominant subclass in the humoral immune response of adult cattle, while in calves, IgG1 appeared as the main prenatally/precolostrally reactive antibody isotype. Provided that precolostral seropositivity reflects postnatal persistent infection with N. caninum, we then postulate that, basically, all of our study calves born form N. caninum-seropositive mothers were prenatally infected with the parasite, and may, thus, all become members of the next transmitting generation.

Ocular toxoplasmosis in pregnancy

PURPOSE

To describe the course of ocular toxoplasmosis during pregnancy.

METHODS

This study was a retrospective, non-comparative case series of four pregnant women who were treated for ocular toxoplasmosis during pregnancy.

RESULTS

All of the participants had severe and treatment-resistant toxoplasmic retinochoroiditis during pregnancy, leaving three of them with decreased visual acuity in spite of aggressive therapy. Delivery of the infant appeared to help the recovery in two patients.

CONCLUSIONS

Pregnant state may provoke the recurrence of ocular toxoplasmosis.

Cortisol and susceptibility to malaria during pregnancy

We measured cortisol and prolactin concentrations in the peripheral venous blood of 23 non-pregnant and 59 pregnant Gabonese women from the second trimester of pregnancy until delivery. Cortisol concentrations were significantly higher in primigravidae women than in multigravidae women between 20 and 25 weeks' gestational age (166 vs. 132 ng/ml, respectively), between 28 and 37 weeks (226 vs. 161 ng/ml) and at delivery (287 vs. 188 ng/ml). Conversely, plasma prolactin levels were highest in multigravidae women. Cortisol and prolactin concentrations both increased with the period of pregnancy (P = 0.01 and P < 0.01, respectively), suggesting that a sustained increase in cortisol level underlies the increased susceptibility of pregnant women, particularly primigravidae women, to malaria. In support of this hypothesis, we found a significant association between cortisol concentration and Plasmodium falciparum infection, on the one hand, and strong correlations with parasite load in P. falciparum-infected primigravidae women, on the other hand (rho between 0.35 and 0.45 with P < 0.01).

Malaria in pregnancy

Recently, there has been a resurgence of malaria in densely populated areas of the United States secondary to human migration from endemic areas where factors such as cessation of vector control, vector resistance to insecticides, disease resistance to drugs, environmental changes, political instability, and indifference, have played a role for malaria becoming an overwhelming infection of these tropical underdeveloped countries. It is important for health care providers of gravida to be alert of the disease and its effects on pregnancy.

Does malaria during pregnancy affect the newborn?

OBJECTIVE

To investigate the effect of malarial infection during pregnancy on the newborn.

METHODS

A retrospective cohort study was conducted at The Aga Khan University Hospital (AKUH), Karachi, using in-patient hospital records over an 11-year period from 1988 to 1999. The incidence of preterm delivery, low birth weight (LBW) and intrauterine growth retardation (IUGR) in 29 pregnant women with malaria, was compared with that in 66 selected pregnant women without malaria, who delivered at the AKUH during the same time period.

RESULTS

Pregnant women with malaria had a 3.1 times greater risk of preterm labor (p=0.14). They were more likely to be anaemic compared to women without malaria (RR=2.9, 95% CI=1.6-5.4) and had a significantly lower mean haemoglobin level (p=0.0001). Maternal malaria was significantly associated with LBW babies (p=0.001). The mean birth weight of infants born to pregnant women with malaria was 461 g less (p=0.0005). No significant association was, however, found between malarial infection during pregnancy and IUGR (p=0.33).

CONCLUSION

Malarial infection during pregnancy is associated with poor maternal and fetal outcome. It is significantly associated with maternal anaemia and LBW infants. Appropriate measures must, therefore, be taken to prevent malaria during pregnancy, especially in endemic areas.

Trichomoniasis among women with vaginal discharge in Jeddah city, Saudi Arabia

During the year of 2003, vaginal discharge specimens were collected from 1767 women aged (15-50) in 6 cardinal hospitals in Jeddah city of Saudi Arabia. The samples were examined for Trichomonas vaginalis, a prevalence rate of 12 (0.7%) were positive. Demographic characters did not show significant relation to the infection rate. All accompanied symptoms were insignificant (P>0.05) except the vaginal consistency which was significant (P<0.05). The studied risk factors were insignificant to the T. vaginalis infection. So, the symptoms were neither reliable to diagnose the vaginal trichomoniasis nor specific underlying factors provoke the infection.

Adverse birth outcomes in a malarious area

To determine factors associated with fetal growth, preterm delivery and stillbirth in an area of high malaria transmission in Southern Malawi, a cross-sectional study of pregnant women attending and delivering at two study hospitals was undertaken. A total of 243 (17.3%) babies were preterm and 54 (3.7%) stillborn. Intra-uterine growth retardation (IUGR) occurred in 285 (20.3%), of whom 109 (38.2%) were low birthweight and 26 (9.1%) preterm. Factors associated with IUGR were maternal short stature [adjusted odds ratio (AOR) 1.6, 95% confidence interval (CI) 1.0-2.5]; primigravidae (AOR 1.9, 95% CI 1.4-2.7); placental or peripheral malaria at delivery (AOR 1.4, 95% CI 1.0-1.9) and maternal anaemia at recruitment (Hb<8 g/dl) (AOR 1.9, 95% CI 1.3-2.7). Increasing parasite density in the placenta was associated with both IUGR (P=0.008) and prematurity (P=0.02). Factors associated with disproportionate fetal growth were maternal malnutrition [mid-upper arm circumference (MUAC)<23 cm, AOR 1.9, 95% CI 1.0-3.7] and primigravidae (AOR 1.8, 95% CI 1.0-3.1). Preterm delivery and stillbirth were associated with <5 antenatal care visits (AOR 2.2, 95% CI 1.3-3.7 and AOR 3.1, 95% CI 1.4-7.0 respectively) and stillbirth with a positive Venereal Disease Research Laboratory (VDRL) test (AOR 4.7, 95% CI 1.5-14.8). Interventions to reduce poor pregnancy outcomes must reduce the burden of malaria in pregnancy, improve antenatal care and maternal malnutrition.

Management of biliary ascariasis in pregnancy

Ascariasis is a helminthic infection of humans caused by the nematode Ascaris lumbricoides. Biliary ascariasis is one of the most common and well described entities caused by ascaris. In endemic areas pregnant women are prone to develop biliary ascariasis. Its management poses a great challenge to both the attending surgeon and the endoscopist. Between January 1993 and March 2003, 15 cases of biliary ascariasis were seen in pregnant patients in our institution. Ultrasonography was used as the main investigative tool. Treatment involved management by conservative, endoscopic, and surgical methods, taking due care of both the mother and the fetus. Ten patients (66.6%) were in the third trimester of pregnancy, and 10 (66.6%) patients were in their third pregnancy. Ultrasonography proved to be the best tool for diagnosing and monitoring worms inside the biliary ductal system. Nine (60%) patients responded to the conservative treatment; endoscopic extraction was successful in 4 (66.6%) patients. Surgical treatment was required in 2 (13.3%) patients. One (6.6%) patient had had spontaneous abortion at 12 weeks gestation, and one (6.6%) patient had a premature labor. The remaining patients had normal pregnancies. Management of biliary ascariasis in pregnancy is a challenge for both the attending surgeon and the endoscopist. Safe and effective management requires special attention to the gestational age and accurate recognition of the specific pathology in the patient. The majority of patients respond to conservative treatment, but endoscopic extraction may be needed in nonresponsive cases. Lead shielding of the fetus and limitation of the total fluoroscopic exposure during therapeutic endoscopy can minimize the teratogenic risk of ionizing radiation. Failures of endoscopic extraction may lead to surgical intervention, which carries risks of fetal wastage and premature labor. Routine worming of women in the child-bearing years is recommended in endemic areas of ascariasis. Though ascariasis is a problem in developing countries, because of increased travel and population migration, clinicians elsewhere should be aware of the problems associated with ascariasis.

Detection of Plasmodium falciparum in pregnancy by laser desorption mass spectrometry

Detection of Plasmodium falciparum malaria during pregnancy is complicated by sequestration of parasites in the placenta, which reduces peripheral blood microscopic detection. Laser desorption mass spectrometry (LDMS) has previously demonstrated sensitive detection of hemozoin from P. falciparum blood cultures and the ability to track parasitemia in a Plasmodium yoelii malaria mouse model. Here we use a simple, dilution in water, blood sample preparation protocol for LDMS detection of malaria in 45 asymptomatic, pregnant Zambian women. We compare LDMS to microscopy and polymerase chain reaction (PCR) analysis. All women were microscopy negative. LDMS detected P. falciparum hemozoin in 15 out of 45 women, while PCR results were positive in 25 women. Compared with PCR, which analyzed 20-30 microL of blood, the sensitivity of LDMS, which analyzed < 1 microL of blood, was 52%, with a specificity of 92%. LDMS is a potentially rapid and more sensitive alternate diagnostic method than microscopy.

Granulomatous villitis formed by inflammatory cells with maternal origin: a rare manifestation type of placental toxoplasmosis

We present a case of placental toxoplasmosis with granulomatous villitis. The patient was a 26-year-old gravida 1 female with the findings of intrauterine death at 16th week of gestation. The pregnancy was terminated. Pathological examination revealed an autolysed fetus and a placenta with necrotizing granulomas within the villous stroma. Encysted Toxoplasma gondii was rarely observed within the granulomas and serologic examination of the mother confirmed acute toxoplasmosis. A fluorocein in situ hybridization examination, using sex chromosome probes, revealed that the villous granulomas were formed by inflammatory cells, originated from the maternal immune system. In conclusion, T. gondii should be taken into consideration as a rare cause of placental granulomatous inflammation. To the best of our knowledge, this is the first case of granulomatous villitis due to toxoplasmosis, in which formation by maternal inflammatory cells has been demonstrated.

Congenital trichinellosis in experimentally infected mice

The present study aimed at allocating the time during pregnancy at which transplacental transmission of Trichinella spiralis (T. spiralis) larvae took place. Swiss albino mice were infected at different durations of pregnancy; five days before mating, on gestation day zero and five days after mating. Furthermore, to study the effect of immunosuppression on transplacental transmission, half of the experimental mice were immunosuppressed using cyclophosphamide drug (Endoxan). The percentage of infected uteri, embryos and placentas and the mean larval count were calculated on day 8 post infection (PI). Moreover, the percentage of infected offspring and the mean larval count in their muscles were estimated on day 30 PI. The results of the present study revealed that, transplacental transmission of T. spiralis could occur in offspring of mice when their mothers are infected before or after pregnancy. This was documented by the presence of larvae in the muscles of offspring. However, the rate of this transmission increased when the mothers are infected at late pregnancy whether they were immunosuppressed or not. The administration of the immunosuppressive drug whether before or after pregnancy increased the rate of infection and the mean larval count in both uteri of mothers and muscles of their offspring. A higher percentage of abortion was demonstrated in females infected before mating in different studied groups.

Fatal experimental transplacental Babesia gibsoni infections in dogs

A Babesia gibsoni infected bitch was mated with an uninfected dog in order to determine whether this parasite could be vertically transmitted. The bitch delivered a litter of four live and one stillborn pup. The four pups died from congenital babesiosis between 14 and 39 days post-birth. Babesia gibsoni DNA was detected in tissue from all five pups. These results show that vertical transmission occurred by the uterine route and not via the transmammary route. This is the first confirmed report of transplacental Babesia infection in any animal species.

Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis

BACKGROUND

We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres.

METHODS

Prospective cohort study of 3 year old children, with and without congenital toxoplasmosis, who were identified by prenatal or neonatal screening for toxoplasmosis in 11 centres in 7 countries. Parents were mailed a questionnaire that comprised all or part of existing validated tools. We determined the effect of characteristics of the centre and child on response, age at questionnaire completion, and response to child drawing tasks.

RESULTS

The questionnaire took 21 minutes to complete on average. 67% (714/1058) of parents responded. Few parents (60/1058) refused to participate. The strongest determinants of response were the score for organisational attributes of the study centre (such as direct involvement in follow up and access to an address register), and infection with congenital toxoplasmosis. Age at completion was associated with study centre, presence of neurological abnormalities in early infancy, and duration of prenatal treatment. Completion rates for individual questions exceeded 92% except for child completed drawings of a man (70%), which were completed more by girls, older children, and in certain centres.

CONCLUSION

Differences in response across European centres were predominantly related to the organisation of follow up and access to correct addresses. The questionnaire was acceptable in all six countries and offers a low cost tool for assessing development, behaviour, and parental concerns and anxiety, in multinational studies.

The effect of maternal, umbilical cord and placental malaria parasitaemia on the birthweight of newborns from South-western Cameroon

AIM

The impact of maternal, umbilical cord and placental malaria parasitaemia on the incidence of low birthweight was investigated in pregnant women reporting for delivery at the Mutengene Maternity Centre, Fako Division, South West Province, Cameroon.

METHODS

The malaria parasitaemia status of 770 umbilical cords, parturient women and placental impression smears were determined by light microscopy using blood samples collected between June 1999 and September 2001. The birthweights (BW) of the newborns were recorded soon after delivery.

RESULTS

The results show that malaria parasites were present in the blood samples of 57 out of 730 (7.8%), 233/711 (32.8%) and 248/735 (33.7%) cord, maternal and placental biopsies respectively. Low birthweight (LBW) was recorded in 72 (9.6%) newborns, and the incidence was higher in primiparae. Newborns of mothers who had malaria parasites in their peripheral blood (12.4%) had a higher incidence (p=0.014) of LBW when compared with malaria parasite-free mothers (6.8%). Similarly, neonates born from malaria-positive placentas (13.5%) had a significantly higher incidence of LBW (p=0.006) than those from parasite-negative placentas (6.8%). Furthermore, newborns of malaria parasite-positive mothers, umbilical cords, placentas and primiparae had lower mean birthweight than malaria-negative mothers, placentas, umbilical cords and multiparae.

CONCLUSION

We suggest that parity and maternal and placental malaria parasitaemia at delivery have an important negative impact on birthweight, especially in first pregnancies. This observation emphasizes the need for appropriate aggressive intervention strategies such as the use of insecticide-treated bed nets or intermittent preventive treatment to control malaria in pregnancy in the study area.

The sick placenta-the role of malaria

The human placenta is an ideal site for the accumulation of Plasmodium falciparum malaria parasites, and as a consequence serious health problems arise for the mother and her baby. The pathogenesis of placental malaria is only partially understood, but it is clear that it leads to a distinct epidemiological pattern of malaria during pregnancy. The objectives of this review are: (1) To review recent data on the epidemiology of malaria in pregnancy, with emphasis on placental malaria; (2) to describe the pathological changes and immunological factors related to placental malaria; and (3) to discuss briefly the functional consequences of this infection for the mother and her baby. The review attempts to bring together local events at the maternal-fetal interface which encompass immunological and pathological processes which relate to the epidemiological pattern of malaria in pregnancy in areas of both high and low malaria transmission. An integrated understanding of the epidemiological, immunological and pathological processes must be achieved in order to understand how to control malaria in pregnancy. The yearly exposure of at least 50 million pregnancies to malaria infection makes it the commonest and most recurrent parasitic infection directly affecting the placenta. These statistics and our limited understanding of its pathogenesis suggest the research priorities on this subject.