Interactions among urogenital, intestinal, skin, and oral infections in pregnant and lactating Panamanian Ngäbe women: a neglected public health challenge

Multiple Infections, Nutrient Deficiencies, and Inflammation as Determinants of Anemia and Iron Status during Pregnancy: The MINDI Cohort

In pregnant women with multiple infections, nutrient deficiencies, and inflammation (MINDI), the study of anemia and iron status is limited. For this cross-sectional study (n = 213 Panamanian indigenous women), we investigated if hemoglobin, anemia (Hb < 110 g/L), ferritin, serum iron, serum transferrin receptor, and hepcidin were associated with (1) maternal nutritional status and supplementation practices, (2) biomarkers of inflammation, and (3) presence/absence of infections. Hierarchical generalized linear and logistic regression models and dominance analyses identified the relative importance of these predictors. Anemia (38%), which was likely underestimated due to low plasma volume (95%), was associated with lower ferritin, vitamin A, and weight-for-height, suggesting anemia of undernutrition. Inflammation was not associated with Hb or anemia; nevertheless, higher CRP was associated with increased odds of low serum iron and higher ferritin and hepcidin, indicating iron restriction due to inflammation. The length of iron supplementation did not enter models for anemia or iron indicators, but a multiple nutrient supplement was associated with higher ferritin and hepcidin. Moreover, iron supplementation was associated with higher odds of vaginal trichomoniasis but lower odds of caries and bacterial vaginosis. The complex pathogenesis of anemia and iron deficiency in MINDI settings may require other interventions beyond iron supplementation.

Helminth-host-environment interactions: Looking down from the tip of the iceberg

In 1978, the theory behind helminth parasites having the potential to regulate the abundance of their host populations was formalized based on the understanding that those helminth macroparasites that reduce survival or fecundity of the infected host population would be among the forces limiting unregulated host population growth. Now, 45 years later, a phenomenal breadth of factors that directly or indirectly affect the host-helminth interaction has emerged. Based largely on publications from the past 5 years, this review explores the host-helminth interaction from three lenses: the perspective of the helminth, the host, and the environment. What biotic and abiotic as well as social and intrinsic host factors affect helminths? What are the negative, and positive, implications for host populations and communities? What are the larger-scale implications of the host-helminth dynamic on the environment, and what evidence do we have that human-induced environmental change will modify this dynamic? The overwhelming message is that context is everything. Our understanding of second-, third-, and fourth-level interactions is extremely limited, and we are far from drawing generalizations about the myriad of microbe-helminth-host interactions.Yet the intricate, co-evolved balance and complexity of these interactions may provide a level of resilience in the face of global environmental change. Hopefully, this albeit limited compilation of recent research will spark new interdisciplinary studies, and application of the One Health approach to all helminth systems will generate new and testable conceptual frameworks that encompass our understanding of the host-helminth-environment triad.

Oral Health Status of Ngäbe-Buglé Children in Panama: A Cross Sectional Study

BACKGROUND

Poor oral health is often more prevalent in rural and resource-limited areas. Evaluating oral health status in these communities is the first step in ensuring adequate future health care for the population. The aim of this study was to assess the oral health status of children aged 6-12 years living in the indigenous Ngäbe-Buglé communities.

METHODS

A cross-sectional study was conducted in two rural indigenous communities of Ngäbe-Buglé on San Cristobal Island in Bocas del Toro, Panama. All children between 6 and 12 years of age and attending local schools were invited to participate, and those whose parents provided oral consent were enrolled. Dental examinations were performed by one trained dentist. To describe oral health, plaque index, DMFT/dmft (decayed, missing, and filled for permanent and primary teeth) index, and developmental defects of enamel index were recorded. Orthodontic characteristics were also evaluated, assessing the prevalence of different molar classes and the prevalence of open bite, lateral crossbite, and scissor bite.

RESULTS

A total of 106 children, representing 37.3% of the child population in the age range attending local schools, were included in this study. The mean plaque index of the entire population was 2.8 (SD 0.8). Caries lesions were more common in children living in San Cristobal (80.0%) compared to those living in Valle Escondido (78.3%), p = 0.827. The mean DMFT/dmft for the entire population was 3.3 (SD 2.9). Developmental defects of enamel were recorded in 49 children (46.2%). The majority of the population had a class I molar relationship (80.0%). Anterior open bite, lateral crossbite, and anterior crossbite were found in 10.4%, 4.7%, and 2.8% of the participants, respectively.

CONCLUSIONS

The oral health of children living in Ngäbe-Buglé communities is generally poor. Oral health education programs for children and adults might play a crucial role in improving the oral health status of the Ngäbe-Buglé population. In addition, the implementation of preventative measures, such as water fluoridation as well as regular toothbrushing with fluoridated toothpaste and more accessible dental care, will be essential in improving future generations' oral health.

Sex—the most underappreciated variable in research: insights from helminth-infected hosts

The sex of a host affects the intensity, prevalence, and severity of helminth infection. In many cases, one sex has been found to be more susceptible than the other, with the prevalence and intensity of helminth infections being generally higher among male than female hosts; however, many exceptions exist. This observed sex bias in parasitism results primarily from ecological, behavioural, and physiological differences between males and females. Complex interactions between these influences modulate the risk of infection. Indeed, an interplay among sex hormones, sex chromosomes, the microbiome and the immune system significantly contributes to the generation of sex bias among helminth-infected hosts. However, sex hormones not only can modulate the course of infection but also can be exploited by the parasites, and helminths appear to have developed molecules and pathways for this purpose. Furthermore, host sex may influence the efficacy of anti-helminth vaccines; however, although little data exist regarding this sex-dependent efficacy, host sex is known to influence the response to vaccines. Despite its importance, host sex is frequently overlooked in parasitological studies. This review focuses on the key contributors to sex bias in the case of helminth infection. The precise nature of the mechanisms/factors determining these sex-specific differences generally remains largely unknown, and this represents an obstacle in the development of control methods. There is an urgent need to identify any protective elements that could be targeted in future therapies to provide optimal disease management with regard to host sex. Hence, more research is needed into the impact of host sex on immunity and protection.

Characteristics of the Skin Microbiome in Selected Dermatological Conditions: A Narrative Review

The skin is the largest and outermost organ of the human body. The microbial diversity of the skin can be influenced by several variable factors such as physiological state, lifestyle, and geographical locations. Recent years have seen increased interest in research aiming at an improved understanding of the relationship between the human microbiota and several diseases. Albeit understudied, interesting correlations between the skin microbiota and several dermatological conditions have been observed. Studies have shown that a decrease or increase in the abundance of certain microbial communities can be implicated in several dermatological pathologies. This narrative review (i) examines the role of the skin microbiota in the maintenance of skin homeostasis and health, (ii) provides examples on how some common skin diseases (acne inversa, candidiasis, psoriasis) are associated with the dysbiosis of microbial communities, and (iii) describes how recent research approaches used in skin microbiome studies may lead to improved, more sensitive diagnostics and individual therapeutics in the foreseeable future.

Multiple Indicators of Undernutrition, Infection, and Inflammation in Lactating Women Are Associated with Maternal Iron Status and Infant Anthropometry in Panama: The MINDI Cohort

Maternal infections, nutrient deficiencies, and inflammation (MINDI) co-exist in lactating indigenous women in Panama, but their impact on maternal iron status and infant growth is unknown. For this secondary analysis of cross-sectional data of lactating mothers from our MINDI cohort, we investigated associations of MINDI variables with maternal anemia, elevated serum transferrin receptor (sTfR), low serum iron, hepcidin, ferritin, and infant weight-for-age (WAZ), length-for-age (LAZ), and head-circumference-for-age (HCAZ) Z-scores in 99 mother-infant dyads. A bootstrapping resampling procedure preselected covariates for inclusion in multivariable regressions models from chronic maternal infections and nutritional status [folate, vitamins A, D, retinol-binding protein (RBP), insulin-growth factor-1 (IGF-1)] and inflammation [C-reactive protein (CRP), cytokines, platelet indices] indicators. Anemia was prevalent (53.5%) but underestimated due to widespread low plasma volume (<2.2 L, 79.9%) and was associated with indicators of malnutrition [lower IGF-1, body mass index (BMI), vitamin D, and intake of green/leafy vegetables], but not inflammation. Higher CRP was associated with lower serum iron, and higher hepcidin and ferritin, whereas maternal platelets were associated with lower HCAZ (β = −0.22), WAZ (β = −0.17), and LAZ (β = −0.17). Higher LAZ was also associated with maternal serum vitamin D (β = 0.23), whereas maternal iron supplementation lowered LAZ (β = −0.22). Assessment of iron status in this MINDI cohort is complex and supplementation strategies must consider consequences for both the mother and the infant.

INTERGROWTH-21 Identifies High Prevalence of Low Symphysis-Fundal Height in Indigenous Pregnant Women Experiencing Multiple Infections, Nutrient Deficiencies, and Inflammation: The Maternal Infections, Nutrient Deficiencies, and Inflammation (MINDI) Cohort

BACKGROUND

In the absence of ultrasound, symphysis-fundal height (SFH) can assess maternal-fetal well-being as it is associated with gestational age, fetal weight, and amniotic fluid volume. However, other modifiers of SFH, including maternal infections, nutrient deficiencies, and inflammation (MINDI), have not been widely explored.

OBJECTIVES

Our objectives were 2-fold: 1) to assess prevalence of low SFH in indigenous Panamanian women using both Pan-American Health Organization (PAHO) and INTERGROWTH-21 standards and 2) to explore associations of SFH with maternal health indicators: infections (oral, skin, urogenital, nematode infections), nutrient deficiencies [protein and iron indicators (ferritin, serum iron, serum transferrin receptor, hepcidin), folate, and vitamins A, D, and B-12], and inflammation [leukocytes, C-reactive protein (CRP), cytokines].

METHODS

For this cross-sectional study, low-SFH-for-gestational-age was assessed using PAHO and INTERGROWTH <10th centile in 174 women at ≥16 weeks of gestation. Bootstrapping selected MINDI variables for inclusion in multivariable fractional polynomial (MFP) logistic regressions for low SFH. Associations of MINDI variables with hepcidin were also investigated.

RESULTS

Prevalence of low SFH was 8% using PAHO, but using INTERGROWTH, 50.6% had SFH <10th centile, including 37.9% <3rd centile. Both PAHO-SFH <10th centile and INTERGROWTH-SFH <3rd centile were associated with higher hepcidin (OR = 1.12, P = 0.008, and OR = 3.04, P = 0.001, respectively) and with lower TNF-α (OR = 0.73, P = 0.012, and OR = 0.93, P = 0.015, respectively). Wood-smoke exposure increased the odds of PAHO-SFH <10th centile (OR = 1.19, P = 0.009), whereas higher BMI decreased the odds of INTERGROWTH-SFH <3rd centile (OR = 0.87, P = 0.012). Lower pulse pressure (OR = 0.90, P = 0.009) and lower inflammatory responses [lower lymphocytes (OR = 0.21, P = 0.026), IL-17 (OR = 0.89, P = 0.011)] distinguished SFH <3rd centile from SFH ≥3rd to <10th centiles using INTERGROWTH-21 standards. The MFP regression for hepcidin controlling for SFH (adjusted R 2 = 0.40, P = 0.001) revealed associations with indicators of inflammation (CRP, P < 0.0001; IL-17, P = 0.012), acidic urinary pH (P = 0.008), and higher intake of supplements (P = 0.035).

CONCLUSIONS

Associations of low SFH with MINDI variables, including hepcidin, highlight its potential for early detection of multicausal in utero growth faltering.

Associations between the vaginal microbiome and Candida colonization in women of reproductive age

BACKGROUND

The composition of bacteria within the vaginal microbiome has garnered a lot of recent attention and has been associated with reproductive health and disease. Despite the common occurrence of yeast (primarily Candida) within the vaginal microbiome, there is still an incomplete picture of relationships between yeast and bacteria (especially lactobacilli), as well as how such associations are governed. Such relationships could be important to a more holistic understanding of the vaginal microbiome and its connection to reproductive health.

OBJECTIVE

The objective of the study was to perform molecular characterization of clinical specimens to define associations between vaginal bacteria (especially Lactobacillus species) and Candida colonization. In vitro studies were conducted to test the 2 most common dominant Lactobacillus species (Lactobacillus crispatus and Lactobacillus iners) in their ability to inhibit Candida growth and to examine the basis for such inhibition.

STUDY DESIGN

A nested cross-sectional study of reproductive-age women from the Contraceptive CHOICE Project was conducted. Vaginal swabs from 299 women were selected to balance race and bacterial vaginosis status, resulting in a similar representation of black and white women in each of the 3 Nugent score categories (normal [0-3], intermediate [4-6], and bacterial vaginosis [7-10]). Sequencing of the 16S ribosomal gene (V4 region) was used to determine the dominant Lactobacillus species present (primarily Lactobacillus iners and Lactobacillus crispatus), defined as >50% of the community. Subjects without dominance by a single Lactobacillus species were classified as Diverse. A Candida-specific quantitative polymerase chain reaction targeting the internally transcribed spacer 1 was validated using vaginal samples collected from a second cohort of women and used to assess Candida colonization. Two hundred fifty-five nonpregnant women with sufficient bacterial biomass for analysis were included in the final analysis. Generalized linear models were used to evaluate associations between Lactobacillus dominance, sociodemographic and risk characteristics, and vaginal Candida colonization. In separate in vitro studies, the potential of cell-free supernatants from Lactobacillus crispatus and Lactobacillus iners cultures to inhibit Candida growth was evaluated.

RESULTS

Forty-two women (16%) were vaginally colonized with Candida. Microbiomes characterized as Diverse (38%), Lactobacillus iners-dominant (39%), and Lactobacillus crispatus-dominant (20%) were the most common. The microbiome, race, and Candida colonization co-varied with a higher prevalence of Candida among black women and Lactobacillus iners-dominant communities compared with white women and Lactobacillus crispatus-dominant communities. Lactobacillus iners-dominant communities were more likely to harbor Candida than Lactobacillus crispatus-dominant communities (odds ratio, 2.85, 95% confidence interval, 1.03-7.21; Fisher exact test, P = .048). In vitro, Lactobacillus crispatus produced greater concentrations of lactic acid and exhibited significantly more pH-dependent growth inhibition of Candida albicans, suggesting a potential mechanism for the clinical observations.

CONCLUSION

In nonpregnant women, Lactobacillus iners-dominant communities were significantly more likely to harbor Candida than Lactobacillus crispatus-dominant communities, suggesting that Lactobacillus species have different relationships with Candida. In vitro experiments indicate that Lactobacillus crispatus may impede Candida colonization more effectively than Lactobacillus iners through a greater production of lactic acid.

Identification of High-Risk Pregnancies in a Remote Setting Using Ambulatory Blood Pressure: The MINDI Cohort

Background: Ambulatory blood pressure is a potential tool for early detection of complications during pregnancy, but its utility in impoverished settings has not been assessed. This cross-sectional study aimed to determine whether maternal infections, nutrient deficiencies and inflammation (MINDI) were associated with four measures of maternal blood pressure (BP) and to determine their association with symphysis-fundal-height (SFH). Methods: Environmental and dietary factors, intake of iron and a multiple-nutrient supplement (MNS), markers of inflammation, protein, anemia, folate, vitamins B₁₂, A and D status, and urogenital, skin, oral and intestinal nematode infections were measured in indigenous pregnant Panamanian women. Stepwise multiple linear and logistic regression models explored determinants of systolic and diastolic blood pressure (SBP, DBP), hypotension (SBP < 100 and DBP < 60), mean arterial pressure (MAP), elevated MAP (eMAP), and pulse pressure (PP). Associations of BP with intestinal nematodes and with SFH Z scores (≥16 wk) were also explored. Results: Despite absence of high SBP or DBP, 11.2% of women had eMAP. Furthermore, 24.1% had hypotension. Linear regression showed that hookworm infection was associated with higher SBP (P = 0.049), DBP (P = 0.046), and MAP (P = 0.016), whereas Ascaris was associated with lower DBP (P = 0.018) and MAP (P = 0.028). Trichomonas was also associated with lower SBP (P < 0.0001) and MAP (P = 0.009). The presence of Trichuris (OR: 6.7, 95% CI 1.0-44.5) and folic acid deficiency (OR: 6.9, 95% CI 1.4-33.8) were associated with increased odds of eMAP. The odds of low BP was higher in the presence of Ascaris (OR: 3.63 ± 2.28, P = 0.040), but odds were lowered by MNS (OR: 0.35 ± 0.11, P = 0.001), more intake of animal-source foods/wk (OR: 0.7, 95% CI 0.5-0.9) and by higher concentrations of IL-17 (OR: 0.87 ± 0.05, P = 0.016). Conclusion: MINDI were bi-directionally associated with blood pressure indicators. In this MINDI cohort, infections, nutrients and cytokines both raised, and lowered BP indices. The presence of eMAP identified pregnant women at risk of hypertension whereas low PP was associated with lower SFH. Therefore, MAP and PP may help in detecting women at risk of adverse pregnancy outcomes in settings with limited access to technology.

C-reactive protein is differentially modulated by co-existing infections, vitamin deficiencies and maternal factors in pregnant and lactating indigenous Panamanian women

Background

The usefulness of C-reactive protein (CRP) as a non-specific marker of inflammation during pregnancy and lactation is unclear in impoverished populations where co-existing infections and vitamin deficiencies are common.

Methods

This cross-sectional study in Panama recruited 120 pregnant and 99 lactating Ngäbe-Buglé women from 14 communities in rural Panama. Obstetric history, indoor wood smoke exposure, fieldwork, BMI, vitamins A, B₁₂, D, and folic acid, and inflammation markers (CRP, neutrophil/lymphocyte ratio (NLR), plateletcrit and cytokines) were measured. Multiple regressions explored both associations of CRP with other inflammatory markers and associations of CRP and elevated CRP based on trimester-specific cut-offs with maternal factors, infections and vitamin deficiencies.

Results

CRP was higher in pregnancy (51.4 ± 4.7 nmol/L) than lactation (27.8 ± 3.5 nmol/L) and was elevated above trimester specific cut-offs in 21% of pregnant and 30% of lactating women. Vitamin deficiencies were common (vitamin A 29.6%; vitamin D 68.5%; vitamin B₁₂ 68%; folic acid 25.5%) and over 50% of women had two or more concurrent deficiencies as well as multiple infections. Multiple regression models highlighted differences in variables associated with CRP between pregnancy and lactation. In pregnancy, CRP was positively associated with greater indoor wood smoke exposure, caries and hookworm and negatively associated with Ascaris and vaginal Lactobacillus and Bacteroides/Gardnerella scores. Consistent with this, greater wood smoke exposure, caries as well as higher diplococcal infection score increased the odds of trimester-elevated CRP concentrations whereas longer gestational age lowered the likelihood of a trimester-elevated CRP. During lactation, folic acid deficiency was associated with higher CRP whereas parity, number of eosinophils and Mobiluncus score were associated with lower CRP. Also, a higher BMI and Trichomonas vaginalis score increased the likelihood of an elevated CRP whereas higher parity and number of eosinophils were associated with lower likelihood of an elevated CRP.

Conclusions

Infections both raise and lower CRP concentrations in pregnant and lactating mothers. Only folic acid deficiency during lactation was associated with higher CRP concentrations. Caution is required when interpreting CRP concentrations in pregnant and lactating women who have co-existing nutrient deficiencies and multiple infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0307-1) contains supplementary material, which is available to authorized users.

Helminth infection during pregnancy: insights from evolutionary ecology

Helminths are parasitic nematodes and trematodes, grouped together because of morphological similarities and commonalities in the effects infections have on hosts. These include complications such as anemia and biasing of immune responses, which can alter susceptibility for other diseases. For pregnant women, these complications might have implications for pregnancy outcomes or neonatal health. Here, I review studies of helminth infections during pregnancy, and ask the following questions: Do helminths affect maternal health or pregnancy outcomes? Are there consequences of maternal infection for infants? What are the effects of antihelminth treatment during pregnancy? The evidence suggests that the answers to these questions depend on the particular helminth species in question, maternal nutritional status, and the presence or absence of comorbid infection with other species, such as malaria. Moreover, there may also be unexpected consequences of treatment, as maternal infections can affect the priming of infant immune systems, with potential effects on infants later in life. These complex interactions suggest that a consideration of the evolutionary history of human–helminth interactions, as well as the ecological context of infections, can help to clarify an understanding of these host–parasite interactions and provide direction for future investigations.