A time-series study of sick building syndrome: chronic, biotoxin-associated illness from exposure to water-damaged buildings

Fungal Contamination of Building Materials and the Aerosolization of Particles and Toxins in Indoor Air and Their Associated Risks to Health: A Review

It is now well established that biological pollution is a major cause of the degradation of indoor air quality. It has been shown that microbial communities from the outdoors may significantly impact the communities detected indoors. One can reasonably assume that the fungal contamination of the surfaces of building materials and their release into indoor air may also significantly impact indoor air quality. Fungi are well known as common contaminants of the indoor environment with the ability to grow on many types of building materials and to subsequently release biological particles into the indoor air. The aerosolization of allergenic compounds or mycotoxins borne by fungal particles or vehiculated by dust may have a direct impact on the occupant’s health. However, to date, very few studies have investigated such an impact. The present paper reviewed the available data on indoor fungal contamination in different types of buildings with the aim of highlighting the direct connections between the growth on indoor building materials and the degradation of indoor air quality through the aerosolization of mycotoxins. Some studies showed that average airborne fungal spore concentrations were higher in buildings where mould was a contaminant than in normal buildings and that there was a strong association between fungal contamination and health problems for occupants. In addition, the most frequent fungal species on surfaces are also those most commonly identified in indoor air, regardless the geographical location in Europe or the USA. Some fungal species contaminating the indoors may be dangerous for human health as they produce mycotoxins. These contaminants, when aerosolized with fungal particles, can be inhaled and may endanger human health. However, it appears that more work is needed to characterize the direct impact of surface contamination on the airborne fungal particle concentration. In addition, fungal species growing in buildings and their known mycotoxins are different from those contaminating foods. This is why further in situ studies to identify fungal contaminants at the species level and to quantify their average concentration on both surfaces and in the air are needed to be better predict health risks due to mycotoxin aerosolization.

Sick Building Syndrome and Other Building-Related Illnesses

Sick building syndrome (SBS) and building-related illnesses are omnipresent in modern high-rise buildings. The SBS is a complex spectrum of ill health symptoms, such as mucous membrane irritation, asthma, neurotoxic effects, gastrointestinal disturbance, skin dryness, sensitivity to odours that may appear among occupants in office and public buildings, schools and hospitals. Studies on large office buildings from USA, UK, Sweden, Finland, Japan, Germany, Canada, China, India, Netherlands, Malaysia, Taiwan, and Thailand, substantiate the occurrence of SBS phenomena. The accumulated effects of a multitude of factors, such as the indoor environmental quality, building characteristics, building dampness, and activities of occupants attribute to SBS. A building occupant manifests at least one symptom of SBS, the onset of two or more symptoms at least twice, and rapid resolution of symptoms following moving away from the workstation or building may be defined as having SBS. Based on the peer-reviewed documentation, this chapter elaborates the magnitude of building-related health consequences due to measurable environmental causations, and the size of the population affected. The mechanisms and causative factors of SBS and illnesses include, for example, the oxidative stress resulting from indoor pollutants, VOCs, office work-related stressors, humidification, odours associated with moisture and bioaerosol exposure. Related regulatory standards and strategies for management of SBS and other illnesses are elaborated.

Antifungal properties of essential oils for improvement of indoor air quality: a review

Concerns regarding indoor air quality, particularly the presence of fungi and moulds, are increasing. The potential for essential oils to reduce, control or remove fungi, is gaining interest as they are seen as a "natural" alternative to synthetic chemical fungicides. This review examines published research on essential oils as a method of fungal control in indoor environments. It was difficult to compare the relative performances of essential oils due to differences in research methods and reporting languages. In addition, there are limited studies that scale up laboratory results and assess the efficacy of essential oils within building environments. However, generally, there appears to be some evidence to support the essential oils clove oil, tea tree oil, oregano, thyme and lemon as potential antifungal agents. Essential oils from heartwood, marjoram, cinnamon, lemon basil, caraway, bay tree, fir, peppermint, pine, cedar leaf and manuka were identified in at least one study as having antifungal potential. Future studies should focus on comparing the effectiveness of these essential oils against a large number of fungal isolates from indoor environments. Studies will then need to focus on translating these results into realistic application methods, in actual buildings, and assess the potential for long-term antifungal persistence.

Antifungal activity of essential oils against fungi isolated from air

Fungal contamination of indoor air is an issue of increasing public health concern. Essential oils have been demonstrated to have antifungal capabilities, but there are limited studies investigating the efficacy of essential oils against fungi relevant to air quality. This study provides a preliminary screening of the antifungal properties of clove, lavender and eucalyptus essential oils against a range of fungal species isolated from environmental air samples. The ability of the essential oils to inhibit fungal growth was examined using the disk diffusion assay on malt extract agar and was compared with vinegar, bleach and limonene, with phenol as a positive control. Results identified essential oils which demonstrated antifungal potential against species of environmental origin. Clove oil was found to be most efficacious, with eucalyptus and lavender oils showing some antifungal potential albeit less broad spectrum and with less persistence over time in this assay. All essentials oils performed better than traditional cleaning compounds such as vinegar. Clove oil would be a suitable candidate for further research to validate its use in improving indoor air quality. Further research should next take into consideration the practical application method, concentration and long-term persistence of antifungal properties.

An Evolutionary-Based Framework for Analyzing Mold and Dampness-Associated Symptoms in DMHS

Among potential environmental harmful factors, fungi deserve special consideration. Their intrinsic ability to actively germinate or infect host tissues might determine a prominent trigger in host defense mechanisms. With the appearance of fungi in evolutionary history, other organisms had to evolve strategies to recognize and cope with them. Existing controversies around dampness and mold hypersensitivity syndrome (DMHS) can be due to the great variability of clinical symptoms but also of possible eliciting factors associated with mold and dampness. An hypothesis is presented, where an evolutionary analysis of the different response patterns seen in DMHS is able to explain the existing variability of disease patterns. Classical interpretation of immune responses and symptoms are addressed within the field of pathophysiology. The presented evolutionary analysis seeks for the ultimate causes of the vast array of symptoms in DMHS. Symptoms can be interpreted as induced by direct (toxic) actions of spores, mycotoxins, or other fungal metabolites, or on the other side by the host-initiated response, which aims to counterbalance and fight off potentially deleterious effects or fungal infection. Further, individual susceptibility of immune reactions can confer an exaggerated response, and magnified symptoms are then explained in terms of immunopathology. IgE-mediated allergy fits well in this scenario, where individuals with an atopic predisposition suffer from an exaggerated response to mold exposure, but studies addressing why such responses have evolved and if they could be advantageous are scarce. Human history is plenty of plagues and diseases connected with mold exposure, which could explain vulnerability to mold allergy. Likewise, multiorgan symptoms in DMHS are analyzed for its possible adaptive role not only in the defense of an active infection, but also as evolved mechanisms for avoidance of potentially harmful environments in an evolutionary past or present setting.

Rapid assemblage of diverse environmental fungal communities on public restroom floors

An increasing proportion of humanity lives in urban environments where they spend most of their lives indoors. Recent molecular studies have shown that bacterial assemblages in built environments (BEs) are extremely diverse, but BE fungal diversity remains poorly understood. We applied culture-independent methods based on next-generation sequencing (NGS) of the fungal internal transcribed spacer to investigate the diversity and temporal dynamics of fungi in restrooms. Swab samples were collected weekly from three different surfaces in two public restrooms (male and female) in San Diego, CA, USA, over an 8-week period. DNA amplification and culturing methods both found that the floor samples had significantly higher fungal loads than other surfaces. NGS sequencing of floor fungal assemblages identified a total of 2550 unique phylotypes (~800 per sample), less than half of which were identifiable. Of the known fungi, the majority came from environmental sources and we found little evidence of known human skin fungi. Fungal assemblages reformed rapidly in a highly consistent manner, and the variance in the species diversity among samples was low. Overall, our study contributes to a better understanding of public restroom floor fungal communities.

Generic hyper-diversity in Stachybotriaceae

The family Stachybotriaceae was recently introduced to include the genera Myrothecium, Peethambara and Stachybotrys. Members of this family include important plant and human pathogens, as well as several species used in industrial and commercial applications as biodegraders and biocontrol agents. However, the generic boundaries in Stachybotriaceae are still poorly defined, as type material and sequence data are not readily available for taxonomic studies. To address this issue, we performed multi-locus phylogenetic analyses using partial gene sequences of the 28S large subunit (LSU), the internal transcribed spacer regions and intervening 5.8S nrRNA (ITS), the RNA polymerase II second largest subunit (rpb2), calmodulin (cmdA), translation elongation factor 1-alpha (tef1) and β-tubulin (tub2) for all available type and authentic strains. Supported by morphological characters these data resolved 33 genera in the Stachybotriaceae. These included the nine already established genera Albosynnema, Alfaria, Didymostilbe, Myrothecium, Parasarcopodium, Peethambara, Septomyrothecium, Stachybotrys and Xepicula. At the same time the generic names Melanopsamma, Memnoniella and Virgatospora were resurrected. Phylogenetic inference further showed that both the genera Myrothecium and Stachybotrys are polyphyletic resulting in the introduction of 13 new genera with myrothecium-like morphology and eight new genera with stachybotrys-like morphology.

Antifungal properties of silver nanoparticles against indoor mould growth

The presence of moulds in indoor environments causes serious diseases and acute or chronic toxicological syndromes. In order to inhibit or prevent the growth of microorganisms on building materials, the disruption of their vital processes or the reduction of reproduction is required. The development of novel techniques that impair the growth of microorganisms on building materials is usually based on silver nanoparticles (AgNPs). It makes them an alternative to other biocides. AgNPs have proven antibacterial activity and became promising in relation to fungi. The aim of the study was to assess growth and morphology of mycelia of typical indoor fungal species: Penicillium brevicompactum, Aspergillus fumigatus, Cladosporium cladosporoides, Chaetomium globosum and Stachybotrys chartarum as well as Mortierella alpina, cultured on agar media. The antifungal activity of AgNPs was also tested in relation to C. globosum and S. chartarum grown on the surface of gypsum drywall. It was found that the presence of AgNPs in concentrations of 30-200mg/l significantly decreased the growth of fungi. However, in the case of M. alpina, AgNPs stimulated its growth. Moreover, strong changes in moulds morphology and colour were observed after administration of AgNPs. Parameters of conidiophores/sporangiophores varied depending on mould region and changed significantly after treatment with AgNPs. The experiments have shown antifungal properties of AgNPs against common indoor mould species. Their application to building materials could effectively protect indoor environments from mould development. However, consideration must be given to the fact that the growth of some fungal strains might be stimulated by AgNPs.

Transcriptomic signatures in whole blood of patients who acquire a chronic inflammatory response syndrome (CIRS) following an exposure to the marine toxin ciguatoxin

Background

Ciguatoxins (CTXs) are polyether marine neurotoxins found in multiple reef-fish species and are potent activators of voltage-gated sodium channels. It is estimated that up to 500,000 people annually experience acute ciguatera poisoning from consuming toxic fish and a small percentage of these victims will develop a chronic, multisymptom, multisystem illness, which can last years, termed a Chronic Inflammatory Response Syndrome (CIRS). Symptoms of ciguatera CIRS include fatigue, cognitive deficits, neurologic deficits, pain and sensitivity to light. There are few treatment options for ciguatera CIRS since little is known about its pathophysiology.

Methods

This study characterizes the transcriptional profile in whole blood of 11 patients with ciguatera-induced CIRS and 11 normal controls run in duplicate using Agilent one color whole genome microarrays. Differential expression was determined by using a combination of moderated t-test p-value and fold change (FC). Significant genes were subjected to gene ontology, principal component analysis and SVM classification. Seven significant genes found by microarray were validated by PCR.

Results

Using a low stringency (p < 0.05 and FC > 1.4) and a high stringency (p < 0.01 and FC > 1.5) filter, the resulting gene sets of 185 and 55, respectively, showed clear separation of cases and controls by PCA as well as 100% classification accuracy by SVM, indicating that the gene profiles can separate patients from controls. PCR results of 7 genes showed a 95% correlation to microarray data. Several genes identified by microarray are important in wound healing (CD9, CD36, vWF and Factor XIII), adaptive immunity (HLA-DQB1, DQB2, IL18R1 and IL5RA) and innate immunity (GZMK, TOLLIP, SIGIRR and VIPR2), overlapping several areas shown to be disrupted in a mouse model of acute exposure to ciguatoxin. Another area of interest was differential expression of long, non-coding sequences, or lncRNA.

Conclusions

Disruptions of innate and adaptive immune mechanisms were recorded at both the genomic and proteomic level. A disruption in the HLA-T cell receptor axis could indicate HLA haplotype sensitivity for this chronic syndrome, as noted in many autoimmune conditions. Taken together, these indicators of illness provide additional insights into pathophysiology and potential therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-015-0089-x) contains supplementary material, which is available to authorized users.

Structural brain abnormalities in patients with inflammatory illness acquired following exposure to water-damaged buildings: a volumetric MRI study using NeuroQuant®

Executive cognitive and neurologic abnormalities are commonly seen in patients with a chronic inflammatory response syndrome (CIRS) acquired following exposure to the interior environment of water-damaged buildings (WDB), but a clear delineation of the physiologic or structural basis for these abnormalities has not been defined. Symptoms of affected patients routinely include headache, difficulty with recent memory, concentration, word finding, numbness, tingling, metallic taste and vertigo. Additionally, persistent proteomic abnormalities in inflammatory parameters that can alter permeability of the blood-brain barrier, such as C4a, TGFB1, MMP9 and VEGF, are notably present in cases of CIRS-WDB compared to controls, suggesting a consequent inflammatory injury to the central nervous system. Findings of gliotic areas in MRI scans in over 45% of CIRS-WDB cases compared to 5% of controls, as well as elevated lactate and depressed ratios of glutamate to glutamine, are regularly seen in MR spectroscopy of cases. This study used the volumetric software program NeuroQuant® (NQ) to determine specific brain structure volumes in consecutive patients (N=17) seen in a medical clinic specializing in inflammatory illness. Each of these patients presented for evaluation of an illness thought to be associated with exposure to WDB, and received an MRI that was evaluated by NQ. When compared to those of a medical control group (N=18), statistically significant differences in brain structure proportions were seen for patients in both hemispheres of two of the eleven brain regions analyzed; atrophy of the caudate nucleus and enlargement of the pallidum. In addition, the left amygdala and right forebrain were also enlarged. These volumetric abnormalities, in conjunction with concurrent abnormalities in inflammatory markers, suggest a model for structural brain injury in "mold illness" based on increased permeability of the blood-brain barrier due to chronic, systemic inflammation.

Comparison of work-related symptoms and visual contrast sensitivity between employees at a severely water-damaged school and a school without significant water damage

BACKGROUND

The National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation (HHE) of a water-damaged school in New Orleans (NO), Louisiana. Our aim in this evaluation was to document employee health effects related to exposure to the water-damaged school, and to determine if VCS testing could serve as a biomarker of effect for occupants who experienced adverse health effects in a water-damaged building.

METHODS

NIOSH physicians and staff administered a work history and medical questionnaire, conducted visual contrast sensitivity (VCS) testing, and collected sticky-tape, air, and dust samples at the school. Counting, culturing, and/or a DNA-based technology, called mold-specific quantitative PCR (MSQPCR), were also used to quantify the molds. A similar health and environmental evaluation was performed at a comparable school in Cincinnati, Ohio which was not water-damaged.

RESULTS

Extensive mold contamination was documented in the water-damaged school and employees (n = 95) had higher prevalences of work-related rashes and nasal, lower respiratory, and constitutional symptoms than those at the comparison school (n = 110). VCS values across all spatial frequencies were lower among employees at the water-damaged school.

CONCLUSIONS

Employees exposed to an extensively water-damaged environment reported adverse health effects, including rashes and nasal, lower respiratory, and constitutional symptoms. VCS values were lower in the employees at the water-damaged school, but we do not recommend using it in evaluation of people exposed to mold. Am. J. Ind. Med. 55:844-854, 2012. This article is a U.S. Government work and is in the public domain in the USA.

Elimination of persistent toxicants from the human body

There is compelling evidence that various chemical agents are important determinants of myriad health afflictions--several xenobiotics have the potential to disrupt reproductive, developmental, and neurological processes and some agents in common use have carcinogenic, epigenetic, endocrine-disrupting, and immune-altering action. Some toxicants appear to have biological effect at miniscule levels and certain chemical compounds are persistent and bioaccumulative within the human body. Despite escalating public health measures to preclude further exposures, many people throughout the world have already accrued a significant body burden of toxicants, placing them at potential health risk. As a result, increasing discussion is underway about possible interventions to facilitate elimination of persistent toxicants from the human organism in order to obviate health affliction and to potentially ameliorate chronic degenerative illness. An overview of the clinical aspects of detoxification is presented with discussion of established and emerging interventions for the elimination of persistent xenobiotics. Potential therapies to circumvent enterohepatic recirculation and a case report highlighting a clinical outcome associated with detoxification are also presented for consideration.

Public facility workers' immunological characteristics involved with development of respiratory allergic diseases in Korea

We evaluated the immuno-pulmonary status of employees working at public facilities to determine whether they are at greater risk of developing respiratory allergies. Fifty-two employees from child daycare centers, elderly nursing homes, subway stations, and hypermarkets, and 17 office workers were recruited. All were subjected to a skin prick test (SPT) for 25 aeroallergens and the methacholine bronchial challenge test. Various immunological parameters, including plasma IgE and IgG4 levels, hematology parameters, and in vitro cytokine production from peripheral T cells, were assessed. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were also determined. Of the facility employees, 54% responded to the SPT, and house dust mite induced positive skin reactions most frequently. Compared to the SPT-negative facility employees and the office workers, the SPT-positive facility employees had upregulated plasma IgE levels and eosinophil frequency in their peripheral blood. Their peripheral T cells also showed elevated IL-4 production relative to IFNgamma production. Four public facility employees who reacted to the methacholine challenge test had elevated eosinophil frequencies, increased plasma IgE levels, and lowered FEV1/FVC values. This study suggests that workers at public facilities could show greater risk towards the development of respiratory allergic diseases.

Neurobehavioral and pulmonary impairment in 105 adults with indoor exposure to molds compared to 100 exposed to chemicals

Patients exposed at home to molds and mycotoxins and those exposed to chemicals (CE) have many similar symptoms of eye, nose, and throat irritation and poor memory, concentration, and other neurobehavioral dysfunctions. To compare the neurobehavioral and pulmonary impairments associated with indoor exposures to mold and to chemicals. 105 consecutive adults exposed to molds (ME) indoors at home and 100 patients exposed to other chemicals were compared to 202 community referents without mold or chemical exposure. To assess brain functions, we measured 26 neurobehavioral functions. Medical and exposure histories, mood states score, and symptoms frequencies were obtained. Vital capacity and flows were measured by spirometry. Groups were compared by analysis of variance (ANOVA) after adjusting for age, educational attainment, and sex, by calculating predicted values (observed/predicted x 100 = % predicted). And p < .05 indicated statistical significance for total abnormalities, and test scores that were outside the confidence limits of the mean of the percentage predicted. People exposed to mold had a total of 6.1 abnormalities and those exposed to chemicals had 7.1 compared to 1.2 abnormalities in referents. Compared to referents, the exposed groups had balance decreased, longer reaction times, and blink reflex latentcies lengthened. Also, color discrimination errors were increased and visual field performances and grip strengths were reduced. The cognitive and memory performance measures were abnormal in both exposed groups. Culture Fair scores, digit symbol substitution, immediate and delayed verbal recall, picture completion, and information were reduced. Times for peg-placement and trail making A and B were increased. One difference was that chemically exposed patients had excess fingertip number writing errors, but the mold-exposed did not. Mood State scores and symptom frequencies were greater in both exposed groups than in referents. Vital capacities were reduced in both groups. Neurobehavioral and pulmonary impairments associated with exposures to indoor molds and mycotoxins were not different from those with various chemical exposures.

An overview of conventional and emerging analytical methods for the determination of mycotoxins

Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results.

Monitoring success of remediation: seven case studies of moisture and mold damaged buildings

Based on seven case studies of buildings that underwent different degrees of moisture and mold damage remediation, we aimed to develop methodology for assessment of the success of the remediation process. Methods used in gauging the success included technical monitoring of performance of building structures and heating, ventilation and air conditioning (HVAC) systems, microbial monitoring of indoor air quality (IAQ), and health effects studies of building occupants. The assessment was based on measurable change in the situations before and after remediation. Based on technical monitoring, remediation was successful in three cases, with partial improvement noted in three cases, whereas no remediation was conducted in one case. Based on microbial monitoring, improvement was detected in one, partial improvement in two and no improvement in two cases, whereas no follow-up was conducted in two cases. Health effect studies (mainly self-reported health status) showed improvement in one case, partial improvement in two cases, and no improvement in two cases, whereas no follow-up was conducted in one case, and in one case, follow-up failed due to low response rate. The results illustrate that it is possible to monitor the effects of remediation using various metrics. However, in some cases, no improvement could be observed in IAQ or occupant health, even if the remediation was considered technically successful, i.e. the remediation was fully completed as recommended. This could be due to many reasons, including: 1) all damage may not have been addressed adequately; 2) IAQ or health may not have been perceived improved regardless of remediation; and/or 3) the methods used may not have been sensitive/specific enough to detect such improvement within the 6-12 months follow-up periods after completion of the remediation. There is a need to further develop tools for monitoring and assessment of the success of moisture damage remediation in buildings.

Current state of the science: health effects and indoor environmental quality

Our understanding of the relationship between human health and the indoor environment continues to evolve. Previous research on health and indoor environments has tended to concentrate on discrete pollutant sources and exposures and on specific disease processes. Recently, efforts have been made to characterize more fully the complex interactions between the health of occupants and the interior spaces they inhabit. In this article we review recent advances in source characterization, exposure assessment, health effects associated with indoor exposures, and intervention research related to indoor environments. Advances in source characterization include a better understanding of how chemicals are transported and processed within spaces and the role that other factors such as lighting and building design may play in determining health. Efforts are under way to improve our ability to measure exposures, but this remains a challenge, particularly for biological agents. Researchers are also examining the effects of multiple exposures as well as the effects of exposures on vulnerable populations such as children and the elderly. In addition, a number of investigators are also studying the effects of modifying building design, materials, and operations on occupant health. Identification of research priorities should include input from building designers, operators, and the public health community.

Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms

Occupants of water-damaged buildings (WDBs) with evidence of microbial amplification often describe a syndrome involving multiple organ systems, commonly referred to as "sick building syndrome" (SBS), following chronic exposure to the indoor air. Studies have demonstrated that the indoor air of WDBs often contains a complex mixture of fungi, mycotoxins, bacteria, endotoxins, antigens, lipopolysaccharides, and biologically produced volatile compounds. A case-series study with medical assessments at five time points was conducted to characterize the syndrome after a double-blinded, placebo-controlled clinical trial conducted among a group of study participants investigated the efficacy of cholestyramine (CSM) therapy. The general hypothesis of the time series study was that chronic exposure to the indoor air of WDBs is associated with SBS. Consecutive clinical patients were screened for diagnosis of SBS using criteria of exposure potential, symptoms involving at least five organ systems, and the absence of confounding factors. Twenty-eight cases signed voluntary consent forms for participation in the time-series study and provided samples of microbial contaminants from water-damaged areas in the buildings they occupied. Twenty-six participants with a group-mean duration of illness of 11 months completed examinations at all five study time points. Thirteen of those participants also agreed to complete a double-blinded, placebo-controlled clinical trial. Data from Time Point 1 indicated a group-mean of 23 out of 37 symptoms evaluated; and visual contrast sensitivity (VCS), an indicator of neurological function, was abnormally low in all participants. Measurements of matrix metalloproteinase 9 (MMP9), leptin, alpha melanocyte stimulating hormone (MSH), vascular endothelial growth factor (VEGF), immunoglobulin E (IgE), and pulmonary function were abnormal in 22, 13, 25, 14, 1, and 7 participants, respectively. Following 2 weeks of CSM therapy to enhance toxin elimination rates, measurements at Time Point 2 indicated group-means of 4 symptoms with 65% improvement in VCS at mid-spatial frequency-both statistically significant improvements relative to Time Point 1. Moderate improvements were seen in MMP9, leptin, and VEGF serum levels. The improvements in health status were maintained at Time Point 3 following a 2-week period during which CSM therapy was suspended and the participants avoid re-exposure to the WDBs. Participants reoccupied the respective WDBs for 3 days without CSM therapy, and all participants reported relapse at Time Point 4. The group-mean number of symptoms increased from 4 at Time Point 2 to 15 and VCS at mid-spatial frequency declined by 42%, both statistically significant differences relative to Time Point 2. Statistically significant differences in the group-mean levels of MMP9 and leptin relative to Time Point 2 were also observed. CSM therapy was reinstated for 2 weeks prior to assessments at Time Point 5. Measurements at Time Point 5 indicated group-means of 3 symptoms and a 69% increase in VCS, both results statistically different from those at Time Points 1 and 4. Optically corrected Snellen Distance Equivalent visual acuity scores did not vary significantly over the course of the study. Group-mean levels of MMP9 and leptin showed statistically significant improvement at Time Point 5 relative to Time Points 1 and 4, and the proportion of participants with abnormal VEGF levels was significantly lower at Time Point 5 than at Time Point 1. The number of participants at Time Point 5 with abnormal levels of MMP9, leptin, VEGF, and pulmonary function were 10, 10, 9, and 7, respectively. The level of IgE was not re-measured because of the low incidence of abnormality at Time Point 1, and MSH was not re-measured because previously published data indicated a long time course for MSH improvement. The results from the time series study supported the general study hypothesis that exposure to the indoor air of WDBs is associated with SBS. High levels of MMP9 indicated that exposure to the complex mixture of substances in the indoor air of the WDBs triggered a pro-inflammatory cytokine response. A model describing modes of action along a pathway leading to biotoxin-associated illness is presented to organize current knowledge into testable hypotheses. The model links an inflammatory response with tissue hypoxia, as indicated by abnormal levels of VEGF, and disruption of the proopiomelanocortin pathway in the hypothalamus, as evidenced by abnormalities in leptin and MSH levels. Results from the clinical trial on CSM efficacy indicated highly significant improvement in group-mean number of symptoms and VCS scores relative to baseline in the 7 participants randomly assigned to receive 2 weeks of CSM therapy, but no improvement in the 6 participants assigned placebo therapy during that time interval. However, those 6 participants also showed a highly significant improvement in group-mean number of symptoms and VCS scores relative to baseline following a subsequent 2-week period of CSM therapy. Because the only known benefit of CSM therapy is to enhance the elimination rates of substances that accumulate in bile by preventing re-absorption during enterohepatic re-circulation, results from the clinical trial also supported the general study hypothesis that SBS is associated with exposure to WDBs because the only relevant function of CSM is to bind and remove toxigenic compounds. Only research that focuses on the signs, symptoms, and biochemical markers of patients with persistent illness following acute and/or chronic exposure to WDBs can further the development of the model describing modes of action in the biotoxin-associated pathway and guide the development of innovative and efficacious therapeutic interventions.

Atovaquone plus cholestyramine in patients coinfected with Babesia microti and Borrelia burgdorferi refractory to other treatment

Ten percent of US patients with Lyme disease are coinfected with Babesia microti. A double-blind, placebo-controlled, crossover trial enrolled 25 patients with confirmed Borrelia burgdorferi/B microti coinfection, abnormal visual contrast sensitivity (VCS), and persistent symptoms despite prior treatment with atovaquone and azithromycin. Patients were randomly assigned to atovaquone suspension or placebo plus cholestyramine for 3 weeks, were crossed over for 3 weeks, and then received open-label atovaquone and cholestyramine for 6 weeks. Symptoms and VCS scores were recorded at baseline and after weeks 3, 6, 9, and 12. Improvements in symptoms and VCS deficits were observed only after at least 9 weeks of treatment. At week 12, 5 patients were asymptomatic, and 16 had a notable reduction in the number of symptoms. The entire cohort demonstrated significant increases in VCS scores. Adverse effects were rare. Patients coinfected with B burgdorferi and B microti derive measurable clinical benefit from prolonged treatment with atovaquone and cholestyramine. Longer-term combination therapy may be indicated.

Chronic biotoxin-associated illness: Multiple-system symptoms, a vision deficit, and effective treatment

Blooms of toxigenic organisms have increased in spatial and temporal extent due to human activities and natural forces that alter ecologic habitats and pollute the environment. In aquatic environments, harmful algal blooms pose a risk for human health, the viability of organisms, and the sustainability of ecosystems. The estuarine dinoflagellate, Pfiesteria piscicida, was discovered in the late 1980s at North Carolina State University as a contaminant in fish cultures. P. piscicida was associated with fish death in laboratory aquaria, and illness among laboratory workers who inhaled the mist above aquaria. Both the fish and humans exhibited signs of toxicity. During the 1990s, large-scale mortality among fish and other aquatic organisms was associated with high concentrations of Pfiesteria sp. in estuaries on the eastern seaboard of North America from New York to Texas. Illness among humans was associated with direct exposure to estuaries and exposures to estuarine aerosols around the time of Pfiesteria-related fish kills. This review of the scientific literature on associations between Pfiesteria and human illness identified some of the possible mechanisms of action by which putative Pfiesteria toxins may have caused morbidity. Particular attention was given to the Pfiesteria-associated, human-illness syndrome known as Possible Estuary Associated Syndrome (PEAS). PEAS was characterized by multiple-system symptoms, deficits in neuropsychological tests of cognitive function, and rapid and severe decrements in visual contrast sensitivity (VCS), an indicator of neurologic function in the visual system. PEAS was diagnosed in acute and chronic illness cases, and was reacquired during re-exposure. Rapid normalization of PEAS signs and symptoms was achieved through the use of cholestyramine therapy. Cholestyramine, a non-absorbable polymer, has been used by humans to lower cholesterol levels since it was approved for that use by the U.S. Food and Drug Administration in 1958. When dissolved in water or juice and taken orally, cholestyramine binds with cholesterol, bile acids, and salts in the intestines, causing them to be eliminated rather than reabsorbed with bile during enterohepatic recirculation. Cholestyramine also has been reported to bind and eliminate a variety of toxic substances. The efficacy of cholestyramine therapy in treatment of PEAS supported the hypothesis that PEAS is a biotoxin-associated illness.