Might procalcitonin help predict imported falciparum malaria in children?

BACKGROUND: Procalcitonin (PCT) has been proposed as a marker for malaria severity in adults, with a threshold of 10 ng/ml for severe falciparum disease. Whether PCT is useful in children is debated. PATIENTS & METHODS: A retrospective case-control study was conducted to compare initial PCT levels in children with uncomplicated malaria and a control group, and between children with uncomplicated and severe malaria. RESULTS: Results showed significantly higher PCT levels in malaria cases compared to the control group and in malaria severe cases compared to uncomplicated cases. A Receiving Operator Characteristic curve established a PCT threshold of 0.65 ng/ml with a negative predictive value of 98.8 % based on a prevalence of 10 %. Analyzing the pooled results of five studies suggested a threshold of 6.17 ng/ml for differentiating uncomplicated and severe malaria. CONCLUSION: PCT might be a useful tool to help rule out malaria and predict potential disease severity in returning travelers.

Major imbalance of thyroid function after laparoscopic sleeve gastrectomy.

In patients with substituted hypothyroidism, laparoscopic sleeve gastrectomy may interfere with thyroid balance by varying body weight or by altering the absorption of hormone therapy. A 58-year-old female patient presented with a major thyroid imbalance after sleeve gastrectomy, manifesting itself in large-scale changes in thyroid stimulating hormone (TSH) levels. The transition from a tablet treatment to a liquid form alleviated burden of treatment, unfortunately without normalising TSH. Our case emphasises the importance of the understanding of hypothalamic-pituitary-thyroid feedback control mechanisms together with good galenic choice, management of associated conditions and the elimination of other causes of variations of TSH levels during the management of hypothyroid patients after sleeve gastrectomy.

Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples.

BACKGROUND: Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI-TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR). METHODS/PRINCIPAL FINDINGS: The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm. CONCLUSIONS/SIGNIFICANCE: Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.

Submicroscopic infections with Plasmodium falciparum during pregnancy and their association with circulating cytokine, chemokine, and cellular profiles.

The immunological consequences of pregnancy-associated malaria (PAM) due to Plasmodium falciparum have been extensively investigated in cross-sectional studies conducted at delivery, but there have been very few longitudinal studies of changes due to PAM during pregnancy. We conducted a prospective study in Benin to investigate the changes associated with PAM in groups of 131 and 111 women at inclusion in the second trimester and at delivery, respectively. Infected women were identified by standard microscopic examinations of blood smears and by quantitative PCR (qPCR) assays and were matched to uninfected control women by age, gestational age, and gravidity. We quantified plasma levels of a panel of soluble immunological mediators and other mediators, as well as the frequencies of peripheral blood mononuclear cell types. Comparisons of these variables in infected and uninfected women used multivariate analyses, and we also assessed the predictive value of variables measured at inclusion for pregnancy outcomes at delivery. In multivariate analyses, peripheral plasma interleukin 10 (IL-10) and gamma interferon-inducible protein 10 (IP-10) levels were associated with PAM at inclusion and at delivery, while higher IL-10 levels distinguished qPCR-detectable submicroscopic infections at inclusion but not at delivery. Maternal anemia at delivery was associated with markers of proinflammatory (increased frequency of monocytes) and anti-inflammatory (increased IL-10 levels and increased activation of regulatory T cells) activity measured at inclusion. Elevated concentrations of IL-10 are associated with the majority of P. falciparum infections during pregnancy, but this marker alone does not identify all submicroscopic infections. Reliably identifying such occult infections will require more sensitive and specific methods.

Plasmodium vivax malaria during pregnancy, Bolivia.

Plasmodium vivax is a major cause of illness in areas with low transmission of malaria in Latin America, Asia, and the Horn of Africa. However, pregnancy-associated malaria remains poorly characterized in such areas. Using a hospital-based survey of women giving birth and an antenatal survey, we assessed the prevalence rates of Plasmodium spp. infections in pregnant women in Bolivia, and evaluated the consequences of malaria during pregnancy on the health of mothers and newborns. P. vivax infection was detected in 7.9% of pregnant women attending antenatal visits, and placental infection occurred in 2.8% of deliveries; these rates did not vary with parity. Forty-two percent of all P. vivax malaria episodes were symptomatic. P. vivax-infected pregnant women were frequently anemic (6.5%) and delivered babies of reduced birthweight. P. vivax infections during pregnancy are clearly associated with serious adverse outcomes and should be considered in prevention strategies of pregnancy-associated malaria.

Gestational age-related changes in the peripheral blood cell composition of sub-Saharan African women.

Gestational age-related changes in the cellular composition of peripheral blood have not been described in sub-Saharan African settings. We conducted longitudinal cohort studies in Beninese and Tanzanian mothers with quantification of peripheral blood mononuclear cell-types ex vivo using flow cytometry. Between the second trimester and delivery the frequency of CD4(+) T cells declined significantly, contrasting with a non-significant increase in CD8(+) T cells, but no changes in T-regulatory, NK or NKT cell frequencies. Antigen-presenting cell profiles were also unaltered, although non-significant trends were evident. These changes resemble in some respects those reported during pregnancies in developed countries, but differ in others.

Evaluation of compliance to congenital Chagas disease treatment: results of a randomised trial in Bolivia.

BACKGROUND: A randomised, unblinded, clinical trial comparing two benznidazole regimens for congenital Chagas disease was carried out to determine whether simplification and reduction in the length of treatment could lead to better treatment compliance. METHODS: This study was conducted in Santa Cruz, Bolivia. Serological screening was carried out in pregnant women, and parasites were sought in the blood of newborns from seropositive mothers. Infected infants were randomly assigned to two treatment groups. Recovery was assessed by parasite seeking at 1 month and 2 months as well as serological tests at 9 months. Assessment of treatment adherence was based on weekly home visits and use of electronic monitors. RESULTS: Benznidazole was given to 63 newborns in group A (5 mg/kg in two daily doses for 60 days) and 61 newborns in group B (7.5 mg/kg in a single daily dose for 30 days). There was no difference in compliance between the two groups. The study confirmed the efficacy and good tolerance of both benznidazole regimens in the treatment of congenital Chagas disease. CONCLUSIONS: The short treatment should be preferred as it allows reducing the dose of benznidazole as well as the cost of treatment.

Peripheral blood cell signatures of Plasmodium falciparum infection during pregnancy.

Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM) is scarce. We conducted a longitudinal, prospective study, both in Benin and Tanzania, including ∼1000 pregnant women in each site with systematic follow-up at scheduled antenatal visits until delivery. We used ex vivo flow cytometry to identify peripheral blood mononuclear cell (PBMC) profiles that are associated with PAM and anaemia, determining the phenotypic composition and activation status of PBMC in selected sub-groups with and without PAM both at inclusion and at delivery in a total of 302 women. Both at inclusion and at delivery PAM was associated with significantly increased frequencies both of B cells overall and of activated B cells. Infection-related profiles were otherwise quite distinct at the two different time-points. At inclusion, PAM was associated with anaemia, with an increased frequency of immature monocytes and with a decreased frequency of regulatory T cells (Treg). At delivery, infected women presented with significantly fewer plasmacytoid dendritic cells (DC), more myeloid DC expressing low levels of HLA-DR, and more effector T cells (Teff) compared to uninfected women. Independent associations with an increased risk of anaemia were found for altered antigen-presenting cell frequencies at inclusion, but for an increased frequency of Teff at delivery. Our findings emphasize the prominent role played by B cells during PAM whenever it arises during pregnancy, whilst also revealing signature changes in other circulating cell types that, we conclude, primarily reflect the relative duration of the infections. Thus, the acute, recently-acquired infections present at delivery were marked by changes in DC and Teff frequencies, contrasting with infections at inclusion, considered chronic in nature, that were characterized by an abundance of immature monocytes and a paucity of Treg in PBMC.

Influence of pregnancy on Trypanosoma cruzi parasitemia in chronically infected women in a rural Bolivian community.

To determine the role of pregnancy on Trypanosoma cruzi parasitemia, a matched cohort study was carried out in a rural Bolivian community comparing parasite rates in gravidae, puerperae, and non-pregnant infected women. A selection of 67 chronically infected women, who delivered between March 2004 and May 2005, were initially evaluated during the third trimester of pregnancy and again after delivery. They were matched for age, parity, and location with 104 seropositive non-pregnant women, who likewise had submitted blood for microscopic examination for T. cruzi parasites in June 2005. Seroreactive pregnant women had a higher rate of T. cruzi parasitemia (14.9%) than matched non-pregnant infected women (2.9%; P = 0.004). After delivery, parasitemia significantly decreased during puerperium (1.5%) compared with the period of pregnancy (14.9%; P = 0.03). This study showed an increase of parasite loads in maternal peripheral blood, during the third trimester, and a significant decline after delivery.

Door-to-door screening as a strategy for the detection of congenital Chagas disease in rural Bolivia.

OBJECTIVE: To demonstrate the feasibility of a house-to-house screening system used for congenital Chagas disease in rural areas based on an active search for pregnant women and newborns in their homes in addition to passive case detection in health facilities. METHODS: Exploratory phase conducted by the research team followed by an operational period coordinated by municipal health service. A blood sample was taken for serological and parasitological tests of Trypanosoma cruzi from pregnant women who were searching antenatal care or visited at home by field investigators. Infants born to T. cruzi-infected women were examined for infection at birth and again at 1 and 7 months of age. RESULTS: 64.5% of the pregnant women were infected. Congenital infection was diagnosed at birth in 4.0% (12/299) of the children born to seroreactive mothers. Twelve additional cases of infection (4%) were diagnosed in children between 1 and 7 months of age. Finally, 37% of the children were lost to follow-up in the exploratory phase and 53% during the operational phase (P=0.002), significantly fewer than in most passive case detection studies. CONCLUSION: Despite poorer outcomes after door-to-door screening activities have been transferred to the health system, a combined strategy based on active and passive case detection appeared to be efficient for identifying rural cases of congenital Chagas disease.

Detectable Trypanosoma cruzi parasitemia during pregnancy and delivery as a risk factor for congenital Chagas disease.

Vector control has led to a drastic decrease in the prevalence of acquired Chagas disease in Latin America, thus redirecting attention to congenital Chagas disease. We report results of a longitudinal study of 359 pregnant women in Yacuiba in southern Bolivia, of whom 147 (40.9%) were infected with Trypanosoma cruzi, to evaluate the relationship between the patency period of the parasitemia and the risk of congenital infection. Maternal infection was assessed by using T. cruzi-specific serologic tests, and parasitemia in mothers and newborns was diagnosed by using microscopic examination of blood in heparinized microhematocrit tubes. Parasitemia was present in 28.6% of the infected women. Its prevalence increased during the third trimester, then decreased at delivery. The likelihood of congenital infection was significantly correlated with the parasite density in the mother's blood. The risk of transmission increased during the third trimester of pregnancy and could explain premature births or low-weight newborns for infected mothers.

Chagas disease: changes in knowledge and management.

More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.

Antibody drop in newborns congenitally infected by Trypanosoma cruzi treated with benznidazole.

OBJECTIVE: To compare the drop of Chagas antibody titres between non-infected and congenitally infected newborns treated by two doses of benznidazole, aiming at evaluating the recovery time and giving recommendations regarding serological criteria of recovery. METHODS: During a clinical trial, the drop of Trypanosoma cruzi antibody titres measured by ELISA tests was followed during the first year of life in congenitally infected newborns treated with different doses of benznidazole and compared to T. cruzi antibody titres in non-parasitaemic newborns. Confirmation of recovery was given by two negative serological tests: Chagas Stat-Pak (CSP) (immunochromatography) and Chagatest v3.0 (ELISA). RESULTS: In non-parasitaemic infants of infected mothers, antibodies of maternal origin disappeared in <8 months while in infected infants, T. cruzi antibodies decreased more slowly and disappeared in 9-16 months allowing to confirm the recovery. All CSP tests were negative before the ninth month while about 10% of ELISA tests remained positive at the 12th month. CONCLUSIONS: Recovery may be confirmed in most cases at 10 months. The CSP test was compared to Chagatest v3.0 ELISA and appeared to give a reliable response. The decrease rate of antibodies does not depend on treatment modes.

Sensitivity and specificity of Chagas Stat-Pak test in Bolivia.

OBJECTIVE: To compare the results of an immunochromatographic test performed on whole blood, Chagas Stat-Pak, with those of an ELISA test using recombinant antigens. METHOD: We tested 995 subjects of a rural population of all ages in the south of Bolivia, 459 pregnant women of the same population and 1030 urban women giving birth from the east of Bolivia. RESULTS: The sensitivity of the CSP test for the entire studied population (n = 2484) was 94.73% [93.35-96.10]; the specificity was 97.33% [96.50-98.15]. However, the specificity differed significantly between rural pregnant and urban birthing women, which could be attributed either to differences of parasite strain or Chagas prevalence. CONCLUSION: The test is simple of use, reliable, relatively inexpensive (<2 US$ each test) and its performances are compatible with a field use for large-scale screenings.

Epidemiological evaluation of Chagas disease in a rural area of southern Bolivia.

We evaluated the prevalence of Chagas disease using a rapid screening test (Chagas Stat-Pak), confirmed by ELISA, in Caraparí, a village of 9000 inhabitants in southern Bolivian Chaco. The prevalence of Trypanosoma cruzi was estimated in a sample of 995 people. The prevalence adjusted on age was 51.2% and was proportionally related to age. We also observed a very significant cline from the south to the north of the locality, where the prevalence ranged from 40 to 80%. In children younger than 11 years, the prevalence was 21.5%, which confirmed the importance of residual vector transmission despite several years of vector control. Among women of procreation age, the prevalence was 63.9%, resulting in a high risk of congenital transmission. The control of the disease requires an increase in vector control and improvement of dwellings before considering children's treatment with trypanocide.

Comparison of Trypanosoma cruzi lineages and levels of parasitic DNA in infected mothers and their newborns.

To better understand the factors involved in maternal-fetal transmission of Trypanosoma cruzi, we compared DNA levels-obtained by use of quantitative real-time PCR and parasitic genotypes determined by PCR amplification followed by hybridization-in Bolivian mothers and their congenitally infected newborns. Mothers and their neonates displayed markedly different parasitic DNA levels, as most maternal estimated parasitemias (> 90%) were < 10 parasites/mL, whereas those of 76% of their newborns were > 1,000 parasites/mL. Comparison of T. cruzi TcII sublineages infecting mothers and newborns showed identity, without evidence of mixed infection in mothers or neonates. Analysis of minor variants of TcIId-genotyped parasites using sequence class probes hybridizing with hypervariable domains of kDNA minicircles showed discrepancies in half of mother/newborn pairs.

Confirmation of the protective effect of Ascaris lumbricoides on Plasmodium falciparum infection: results of a randomized trial in Madagascar.

A controlled randomized trial of anti-helminthic treatment was undertaken in 1996-1997 in a rural area of Madagascar where populations were simultaneously infected with Ascaris lumbricoides, Plasmodium falciparum, and Schistosoma mansoni. Levamisole was administered bimonthly to 107 subjects, whereas 105 were controls. Levamisole was highly effective in reducing Ascaris egg loads in the treated group (P < 10(-3) at all visits), whereas it had no effect on schistosomiasis. Subjects 5-14 years of age, treated with levamisole, had a significant increase of their P. falciparum densities compared with controls (P = 0.003). There was no effect of the treatment on children 6 months to 4 years of age, nor on adults > 15 years of age. This study confirms the results of a randomized trial, which showed a negative interaction in those > 5 years of age between Ascaris and malaria parasite density in another Malagasy population, submitted to a higher malaria transmission.

Congenital Chagas disease in Bolivia is not associated with DNA polymorphism of Trypanosoma cruzi.

This study aims to typify the Trypanosoma cruzi (sub)lineage(s) in umbilical cord blood of congenitally infected Bolivian newborns, using PCR amplifications of "Region Markers", mini-exon or kDNA fragments followed by hybridization or sequencing. New probes were also designed to distinguish three variants within the TcIId sublineage. The IIb, IId, or IIe T. cruzi sublineages, as well as different variants of the IId sublineage, were detected in infected neonates, whereas mixed infections were not found. The frequencies of the IId sublineage were similar in neonates (95.1%) and adults of the same area (94.1%). The IId-infected newborns displayed either asymptomatic, or severe and fatal clinical forms of congenital Chagas disease, as well as low or high parasitemia. Altogether these data show that T. cruzi DNA polymorphism, based on the presently available markers, is not associated with the occurrence of congenital infection or the development of severe clinical forms of congenital Chagas disease.

Parasitic co-infections: does Ascaris lumbricoides protect against Plasmodium falciparum infection?

A controlled randomized trial of antihelminthic treatment was undertaken in 1996-1997 in a rural area of Madagascar where populations were simultaneously infected with Ascaris lumbricoides and Plasmodium falciparum. Levamisole was administered bimonthly to 164 subjects, randomized on a family basis, whereas 186 were controls. While levamisole proved to be highly effective in reducing Ascaris egg loads in the treated group (P < 10(-3) at all bimonthly visits), subjects more than 5 years of age, treated with levamisole had a significant increase in their P. falciparum densities compared with controls (P = 0.02), whereas there was no effect of anti-helminthic treatment on children 6 months to 4 years of age. The demonstration of a clear negative interaction between Ascaris infection and malaria parasite density has important implications. Single community therapy programs to deliver treatments against several parasitic infections could avoid an increase of malaria attacks after mass treatment of ascariasis.