Accuracy, acceptability, and feasibility of diagnostic tests for the screening of Strongyloides stercoralis in the field (ESTRELLA): a cross-sectional study in Ecuador.

BACKGROUND: WHO recommends the implementation of control programmes for strongyloidiasis, a neglected tropical disease caused by Strongyloides stercoralis. Specific recommendations on the diagnostic test or tests to be used for such programmes have yet to be defined. The primary objective of this study was to estimate the accuracy of five tests for strongyloidiasis. Secondary objectives were to evaluate acceptability and feasibility of use in an endemic area. METHODS: The ESTRELLA study was a cross-sectional study for which we enrolled school-age children living in remote villages of Ecuador. Recruitment took place in two periods (Sept 9-19, 2021, and April 18-June 11, 2022). Children supplied one fresh stool sample and underwent blood collection via finger prick. Faecal tests were a modified Baermann method and an in-house real-time PCR test. Antibody assays were a recombinant antigen rapid diagnostic test; a crude antigen-based ELISA (Bordier ELISA); and an ELISA based on two recombinant antigens (Strongy Detect ELISA). A Bayesian latent class model was used to analyse the data. FINDINGS: 778 children were enrolled in the study and provided the required samples. Strongy Detect ELISA had the highest sensitivity at 83·5% (95% credible interval 73·8-91·8), while Bordier ELISA had the highest specificity (100%, 99·8-100). Bordier ELISA plus either PCR or Baermann had the best performance in terms of positive and negative predictive values. The procedures were well accepted by the target population. However, study staff found the Baermann method cumbersome and time-consuming and were concerned about the amount of plastic waste produced. INTERPRETATION: The combination of Bordier ELISA with either faecal test performed best in this study. Practical aspects (including costs, logistics, and local expertise) should, however, also be taken into consideration when selecting tests in different contexts. Acceptability might differ in other settings. FUNDING: Italian Ministry of Health. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

A Low-Cost SARS-CoV-2 rRBD ELISA to Detect Serostatus in Ecuadorian Population with COVID-19.

Laboratory diagnosis of the COVID-19 relies on RT-PCR to amplify specific fragments of SARS-CoV-2 genome. However, serological tests are required to determine the immune response elicited after infection. Here, we analyzed convalescent sera collected from positive individuals by RT-PCR to SARS-CoV-2 (n = 78), Zika (n = 20), dengue (n = 20), chikungunya (n = 54), intestinal parasites (n = 11), and HIV (n = 1), from different areas of Ecuador, with an in-house ELISA using a SARS-CoV-2 receptor binding domain recombinant (rRBD) antigen to detect IgG antibodies elicited by SARS-CoV-2 infection. Of the 78 samples positive for SARS-CoV-2 by RT-PCR, 73 showed high absorbance value compared with the cutoff and five were negative. All tested sera from other infections showed no reactivity. Sensitivity, specificity, positive predictive value, and negative predictive value were 93.6%, 100%, 100%, and 95.4%, respectively. This in-house anti-IgG rRBD ELISA offers an economic and simple alternative to determine IgG immune responses after SARS-CoV-2 infection.

Community Epidemiology Approach to Parasitic Infection Screening in a Remote Community in Ecuador.

The Awa indigenous people of Ecuador live in remote areas and were included in health programs only recently. The first screening for parasitic infections in the Awa communities was implemented in the context of community epidemiology. During the site visits in each community, the health-care staff collected the samples for stool microscopy and serology for Strongyloides. A total of 705 individuals consented for the study, representing 40% of the Awa population living in the targeted communities; 184 (26%) participants supplied a stool sample. Giardia intestinalis was found in about 11% of samples. Prevalence of Ascaris lumbricoides and Trichuris trichiura was 54.9% and 36.9%, respectively. No hookworm eggs were found. In addition, Strongyloides stercoralis larvae were found in eight individuals (4.3%), whereas serology was positive in 22.7% of the individuals tested. The community-based approach resulted in an impressive participation. There was a high prevalence of parasites associated with relevant morbidity.

Use of Real-Time Polymerase Chain Reaction to Differentiate between Pathogenic Entamoeba histolytica and the Nonpathogenic Entamoeba dispar in Ecuador.

Microscopic examination of stool samples has been considered to be the "gold standard" for diagnosis of intestinal parasites. Recently, polymerase chain reaction (PCR) has been approved by the World Health Organization as the method of choice for the diagnosis of Entamoeba histolytica. Of the 106 stool samples collected from the Esmeraldas and Pichincha provinces of Ecuador, all (100%) were positive for E. histolytica/Entamoeba dispar by light microscopy, whereas using real-time PCR (RT-PCR) DNA amplification, 74 (69.8%) were positive for E. dispar and only three (2.8%) were positive for E. histolytica. Some 29 (27.4%) samples were negative for the presence of either E. histolytica or E. dispar, this may be due the presence of Entamoeba mosksvskii, which is morphologically identical to E. histolytica/E. dispar and not specifically targeted by the RT-PCR used. These results indicate the necessity of reevaluating the epidemiology of amebiasis in Ecuador as the prominent species found are nonpathogenic.

Bacterial identification of the vaginal microbiota in Ecuadorian pregnant teenagers: an exploratory analysis.

BACKGROUND: Bacterial vaginosis (BV) is a microbial imbalance (i.e., dysbiosis) that can produce serious medical effects in women at childbearing age. Little is known, however, about the incidence of BV or vaginal microbiota dysbiosis in pregnant teenagers in low and middle-income countries such as Ecuador. The scope of this exploratory analysis was to study the relationship between epidemiologic and microbial risk factors. Among the microbiology risk factors this study investigated five Lactobacillus species, two of them know in preview studies as microbiology risk factors for BV development (Lactobacillus acidophilus and Lactobacillus iners), and the last three known for being associated with a healthy vaginal tract (Lactobacillus crispatus, Lactobacillus gasseri and Lactobacillus jensenii). In addition, fastidious anaerobes known to be microbial risk factors for BV development in pregnant teenagers were searched as well, more exactly, Gardnerella vaginalis, Atopobium vaginae and Mobiluncus mulieris. METHODS: Ninety-five healthy adolescent pregnant women, visiting a secondary level hospital in Quito, Ecuador, were enrolled into the study in 2015. The enrolled patients were between 10 to 13 weeks of pregnancy. Four epidemiological risk factors were collected in a survey: age, civil status, sexual partners and condom use. Also, vaginal pH was measured as a health risk factor. DNA was extracted from endocervical and exocervical epithelia from all the patients' samples. PCR analysis was performed in order to characterize the presence of the eight bacterial species known as risk factors for BV development, targeting three anaerobes and five Lactobacillus species. Univariate and multivariate analysis were performed to identify associated factors for the presence of anaerobic species using logistic regression. RESULTS: The 95 vaginal microflora samples of these teenagers were analyzed. Two of the bacterial species known to cause BV: A. vaginae (100%) and G. vaginalis (93.7%) were found in high prevalence. Moreover, the most predominant bacterial Lactobacillus species found in the pregnant teenagers' vaginal tract were L. crispatus (92.6%), L. iners (89.5%) and L. acidophilus (87.4%). In addition, the average vaginal pH measured in the study population was 5.2, and high pH was associated with the presence of the three-anaerobic species (p = 0.001). Finally, L. jensenii's presence in the study decreased in 72% the occupation of the three anaerobes. DISCUSSION: This work identified a high pH as a risk factor for BV anaerobes' presence in adolescent pregnant women. Moreover, this study identified L. crispatus, L. iners and L. acidophilus to be the most abundant species in our study population. From all fastidious anaerobes analyzed in this study, A. vaginae was present in all pregnant teenagers. To conclude, L. jensenii could be a potential healthy vaginal microbiota candidate in pregnant teenagers and should be further analyzed in future studies.

First description of Trypanosoma cruzi human infection in Esmeraldas province, Ecuador.

Chagas disease was described in Ecuador in 1930 in the province of Guayas and thereafter in various provinces. Triatomine were reported in the province of Esmeraldas but no human infection has been described. Here we report the first evidence that the disease does exist in the province of Esmeraldas. In indigenous Awá communities located in the northwest jungle of the Esmeraldas province, 144 individuals were tested using ELISA and PCR for T.cruzi of which 5 (3.47%) were positive. Twenty eight triatomine were collected, 27 were Triatoma dispar and 1 Pastrongylus rufotuberculatus, T.cruzi was detected in 11 (42.3%) of 26 insects.

Effect of intravenous hydralazine infusion on maternal plasma nitric oxide levels in gestations complicated with severe preeclampsia: a pilot study.

AIM: To investigate the effect of intravenous hydralazine infusion on maternal nitric oxide (NO) levels. METHODS: This pilot study comprised 40 (n = 40) gestations complicated with severe preeclampsia to whom maternal plasma NO levels were determined by chemiluminescence before and after hydralazine administration. Blood pressure values were concomitantly assessed. RESULTS: After 20 min of intravenous hydralazine infusion blood pressure values decrease significantly in term and preterm gestations. This was accompanied by an overall significant decrease in mean plasma NO values (38.7 ± 12.9 to 35.4 ± 13.9 µmol/L, p < 0.05). Despite this, NO values decreased in 67.5% of cases (a 17.6% from baseline) and increased in 32.5% (a 14.8% from baseline) (p < 0.05 for both). Blood pressure decrease (%) was lower (systolic and diastolic) among those displaying a NO decrement than in the increment group. Interestingly, gestational age was higher in the group displaying decreased NO; however, this did not reach statistical significance (37.5 ± 2.7 vs. 35.9 ± 2.8 weeks, p = 0.08). CONCLUSION: The results of this study fail to demonstrate a similar NO secretion after hydralazine infusion in women with severe preeclampsia.

Maternal plasma and amniotic fluid coenzyme Q10 levels in preterm and term gestations: a pilot study.

OBJECTIVE: To measure maternal plasma and amniotic fluid coenzyme Q10 (CoQ10) levels in preterm and term gestations. STUDY DESIGN: This pilot study comprised a convenience sample of 72 women admitted for labor with singleton live gestations and intact membranes (preterm n = 27 and term n = 45). RESULTS: Median [interquartile range] maternal plasma CoQ10 levels did not differ among the studied women (preterm, 0.47 [0.12] vs. term, 0.47 [0.23] mmol/L, p = 0.90). Overall CoQ10 amniotic fluid levels were nearly tenfold lower than those found in maternal plasma, with a significant lower level observed among those delivering preterm (0.050 [0.05] vs. 0.062 [0.04] mmol/L, p = 0.007). Multiple linear regression analysis controlling for several covariates determined a significant correlation between amniotic fluid CoQ10 levels and neonatal gestational age. CONCLUSION: This is the first study to assess CoQ10 levels in amniotic fluid during pregnancy in which levels were significantly lower among those delivering preterm. More research is warranted in this regard.

Plasma and placental nitric oxide levels in women with and without pre-eclampsia living at different altitudes.

OBJECTIVE: To investigate the nitric oxide (NO) levels in the plasma and the placentas of pregnant women with pre-eclampsia and women without pre-eclampsia, and to determine the effect of high or low altitude of residence. METHODS: NO was determined by chemoluminescence and group comparisons were performed. RESULTS: Women with pre-eclampsia (n=63) had higher plasma NO levels (38.6+/-17.44 vs 30.6+/-12.44 micromol/L, P=0.004) and higher placental NO levels (38.5+/-17.0 vs 24.3+/-7.16 ng/mg protein, P<0.05) compared with women without pre-eclampsia. A similar trend was found when comparisons were made according to altitude of residence. NO levels were significantly higher in the plasma of pre-eclamptic women living at sea level (41.11+/-18.78 vs 28.96+/-9.57 micromol/L, P=0.003), and in the placentas of women living at high altitude (39.51+/-16.98 vs 21.91+/-6.64 ng/mg protein, P<0.0001). CONCLUSION: Women with pre-eclampsia had higher plasma and placental NO levels and the differences were associated with altitude of residence.

Coenzyme Q10 levels in women with preeclampsia living at different altitudes.

BACKGROUND: Preeclampsia is a common disorder of pregnancy exhibiting abnormal plasma and placental coenzyme Q10 (CoQ10) levels when compared to normal pregnancies. OBJECTIVE: To evaluate CoQ10 levels both in plasma and placenta among normal pregnant (n = 60) and preeclamptic (n = 63) primigravid women and determine the effect of high or low altitude residency. STUDY DESIGN: CoQ10 was determined using High Performance Liquid Chromatography (HPLC) technique and group comparisons were performed. RESULTS: Preeclamptic women living at high altitude displayed significantly lower CoQ10 plasma levels (0.64 +/- 0.23 vs. 0.82 +/- 0.46 micromol/L, p = 0.05). No differences were found in CoQ10 plasma levels among women living at sea level. Interestingly, plasma CoQ10 levels at low altitude in normal pregnancies were significantly lower than high altitude normal pregnancies. Compared to normal pregnancies, preeclamptic women displayed higher placental CoQ10 content, which was only significant among those living at sea level (0.120 +/- 0.07 vs. 0.076 +/- 0.04 ng/mg protein, p < 0.005). Normal pregnant women living at high altitude displayed higher placental CoQ10 content when compared to those residing at sea level (p < 0.0005). CONCLUSION: Women suffering from preeclampsia (high or low altitude) display high placental CoQ10 content, with significant low plasma CoQ10 levels among those residing in high altitude. More research is warranted to establish the cause-effect relationship between CoQ10 levels and preeclampsia.

Coenzyme Q10 is increased in placenta and cord blood during preeclampsia.

Preeclampsia is a common (approximately 7% of all pregnancies) disorder of pregnancy in which the normal hemodynamic response to pregnancy is compromised. Despite many years of intensive research, the pathogenesis of preeclampsia is still not fully understood. The objective of the present study was to investigate the levels of coenzyme Q(10) (CoQ(10)) in placental tissue compared to maternal and umbilical cord levels both during normal pregnancy and in those complicated with preeclampsia. Pregnant women (n = 30) and women with preeclampsia (n = 30) were included. Maternal, newborn cord blood levels and placental content of coenzyme Q(10) were measured by high performance liquid chromatography (HPLC). Plasma coenzyme Q(10) levels were significantly higher in normal pregnant women than in women with preeclampsia. CoQ(10) content in placenta from women with preeclampsia (mean 0.28 SEM 0.11 nmol/mg protein) was significantly higher compared to normal pregnancy (mean 0.09 SEM 0.01 nmol/mg protein; p = 0.05). Levels of CoQ(10) in cord blood from normal pregnant women (mean 0.30 SEM 0.05 micromol/l) were significantly lower than in preeclamptic women (mean 4.03 SEM 2.38 micromol/l). In conclusion, these data indicate a possible involvement of CoQ(10) in preeclampsia that might bear deep physiopathological significance and deserve to be further elucidated.

Intraplatelet cyclic guanosine-3',5'-monophosphate levels during pregnancy and preeclampsia.

OBJECTIVE: To investigate the intraplatelet cyclic guanosine-3',5'-monophosphate (cGMP) levels during normal pregnancy and preeclampsia. STUDY DESIGN: Pregnant women (n = 15), women with preeclampsia (n = 15), and nonpregnant, normotensive women (n = 15) were included. Intraplatelet cyclic guanosine-3',5'-monophosphate levels were measured by an enzyme-linked immunosorbent assay. RESULTS: Intraplatelet cGMP levels were significantly different among all groups (p < 0.02). The values were higher in normal pregnant women (mean 19.8 SD 2.6 fmol/10(5) platelets) in comparison to nonpregnant women (mean 7.6 SD 0.3 fmol/10(5)platelets; p = 0.001) and women with preeclampsia (mean 11.3 SD 1.8 fmol/10(5) platelets; p = 0.05). Plasma nitric oxide levels did not reveal differences between all groups. CONCLUSIONS: The results of this study in a high-risk Andean population demonstrated that intraplatelet cyclic guanosine-3',5'-monophosphate levels are decreased during preeclampsia compared to normal pregnancy, suggesting a lack in action of nitric oxide.

Preeclampsia is associated with a decrease in plasma coenzyme Q10 levels.

Preeclampsia is a common ( approximately 7% of all pregnancies) disorder of human pregnancy in which the normal hemodynamic response to pregnancy is compromised. Despite many years of intensive research, the pathogenesis of preeclampsia is still not fully understood. The objective of the present study was to investigate the concentration of coenzyme Q10 in normal pregnancy and preeclampsia. Pregnant women (n = 18), women with preeclampsia (n = 12), and nonpregnant normotensive women (n = 22) were included. Plasma levels of coenzyme Q10 were measured by high-performance liquid chromatography. Plasma coenzyme Q10 levels were significantly higher in normal pregnant women (mean = 1.08, SEM = 0.08 umol/l; p <.005) in comparison to nonpregnant women (mean = 0.86, SEM = 0.16 umol/l) and women with preeclampsia (mean = 0.7, SEM = 0.03 umol/l; p <.0001). These results demonstrated that during preeclampsia there is a significant decrease in plasma levels of coenzyme Q10 compared to normal pregnant women, and compared to those who are not pregnant.

Physiological changes in platelet aggregation and nitric oxide levels during menstrual cycle in healthy women.

Hormonal levels, mainly those of estrogens, protect women from the appearance of cardiovascular diseases by an increasing nitric oxide (NO) activity. NO is an endogenous vasodilator and antiaggregating substance. We decided to investigate platelet function and plasma levels of nitric oxide during preovulatory and midluteal phases in young and healthy women with normal menstrual cycles (MCs). Nine young, healthy female subjects had recorded three consecutive MCs before entering this program. Platelet-rich plasma (PRP) was used for the determination of platelet aggregation and NO measurements. Moreover, platelet sensitivity to the inhibitory effect of exogenous NO was tested. The EC(50) of collagen showed no differences between the preovulatory (1.36+/-0.16 microg/mL) and the midluteal (1.31+/-0.08 microg/mL; P, NS) phases. However, the EC(90) during the preovulatory phase was higher (2.05+/-0.2 microg/mL) than during the midluteal phase (1.8+/-0.6 microg/mL). Plasma levels of NO were lower during the preovulatory phase (19.1+/-2 microM) in comparison to the midluteal phase (20.9+/-2.3 microM). Interestingly, the exogenous amount of NO to produce at least half of the inhibition of an EC(90) collagen-induced aggregation was higher at the preovulatory phase (323.3+/-60.9 nM) than during the midluteal phase (240.0+/-37.5 nM; P, NS). We propose that during the follicular phase platelets rather use NO produced by the endothelium; therefore, it is necessary to add more agonist to activate those, but it results in higher consumption of circulating NO, whereas during luteal-phase platelets are not able to use NO, requiring lower amounts of agonist and thus resulting in higher plasma levels of NO. This is an interesting fact in research on cardiovascular diseases of women.