Association between Giardia and arthritis or joint pain in a large health insurance cohort: could it be reactive arthritis?

Prevalence of Giardia duodenalis among Asian children: a systematic review and meta-analysis

Giardia duodenalis is one of the major causes of diarrhea among children. We performed a systematic review and meta-analysis to assess the prevalence of G. duodenalis and associated risk factors among Asian children. We searched online databases (PubMed, Scopus and Web of Science) and Google Scholar search engine for studies published from 1 January 2000 to 15 March 2022 that measured the prevalence of G. duodenalis among Asian children. Accordingly, the pooled prevalence and 95% CIs were estimated using a random-effects meta-analysis model for the included studies. A total of 182 articles from 22 Asian countries met the inclusion criteria. The pooled prevalence of G. duodenalis infection among Asian children was estimated as 15.1% (95% CI 14.1 to 16%). The highest and lowest pooled prevalence values of G. duodenalis infection were estimated for Tajikistan and China as 26.4% (95% CI 22.9 to 30%) and 0.6% (95% CI 0.001 to 1.02%), respectively. The infection had a higher prevalence in males than in females (OR=1.24; 95% CI 1.16 to 1.31; p<0.001), which was statistically significant. Giardiasis is common among Asian children, hence, a prevention and control scheme of this protozoan in children should be considered by health officials and health policymakers, especially in Asian countries where the prevalence is highest.

Molecular detection and genetic characteristics of Giardia duodenalis in dairy cattle from large-scale breeding farms in Xinjiang, China

Giardia duodenalis is an intestinal protozoan that can infect both humans and animals, leading to public health issues and economic losses in the livestock industry. G. duodenalis has been reported to infect dairy cattle, but there is limited information available on large-scale dairy farms in Xinjiang, China. The study collected 749 fresh faecal samples from five large-scale cattle farms in Xinjiang, China. The study used a nested PCR assay of the small subunit ribosomal RNA (SSU rRNA*) gene to determine the presence of G. duodenalis. The results showed that 24.0% (180/749) of dairy cattle were positive for G. duodenalis, with the highest infection rate observed in pre-weaned calves (45.1%, 69/153). Among the 180 G. duodenalis positive samples, three assemblages were identified: assemblage E (n = 176), assemblage A (n = 3) and assemblage B (n = 1). Sixty-nine, 67 and 49 sequences were obtained for the beta-giardin (bg*) gene, the glutamate dehydrogenase (gdh*) gene and the triose phosphate isomerase (tpi*) gene, respectively. Thirteen novel sequences of assemblage E were identified, including five sequences from the bg* gene, four sequences from the gdh* gene and four sequences from the tpi* gene. This study found that 32 G. duodenalis assemblage E isolates formed 26 MLGs, indicating genetic variation and geographic isolation-based differentiation in bovine-derived G. duodenalis assemblage E. These findings provide fundamental insights into the genetic diversity of G. duodenalis in dairy cattle and can aid in the prevention and control of its occurrence in large-scale dairy cattle farms.

Repurposing Terfenadine as a Novel Antigiardial Compound

Giardia lamblia is a highly infectious protozoan that causes giardiasis, a gastrointestinal disease with short-term and long-lasting symptoms. The currently available drugs for giardiasis treatment have limitations such as side effects and drug resistance, requiring the search for new antigiardial compounds. Drug repurposing has emerged as a promising strategy to expedite the drug development process. In this study, we evaluated the cytotoxic effect of terfenadine on Giardia lamblia trophozoites. Our results showed that terfenadine inhibited the growth and cell viability of Giardia trophozoites in a time-dose-dependent manner. In addition, using scanning electron microscopy, we identified morphological damage; interestingly, an increased number of protrusions on membranes and tubulin dysregulation with concomitant dysregulation of Giardia GiK were observed. Importantly, terfenadine showed low toxicity for Caco-2 cells, a human intestinal cell line. These findings highlight the potential of terfenadine as a repurposed drug for the treatment of giardiasis and warrant further investigation to elucidate its precise mechanism of action and evaluate its efficacy in future research.

Gut Microbial Perturbation and Host Response Induce Redox Pathway Upregulation along the Gut-Liver Axis during Giardiasis in C57BL/6J Mouse Model

Apicomplexan infections, such as giardiasis and cryptosporidiosis, negatively impact a considerable proportion of human and commercial livestock populations. Despite this, the molecular mechanisms of disease, particularly the effect on the body beyond the gastrointestinal tract, are still poorly understood. To highlight host-parasite-microbiome biochemical interactions, we utilised integrated metabolomics-16S rRNA genomics and metabolomics-proteomics approaches in a C57BL/6J mouse model of giardiasis and compared these to Cryptosporidium and uropathogenic Escherichia coli (UPEC) infections. Comprehensive samples (faeces, blood, liver, and luminal contents from duodenum, jejunum, ileum, caecum and colon) were collected 10 days post infection and subjected to proteome and metabolome analysis by liquid and gas chromatography-mass spectrometry, respectively. Microbial populations in faeces and luminal washes were examined using 16S rRNA metagenomics. Proteome-metabolome analyses indicated that 12 and 16 key pathways were significantly altered in the gut and liver, respectively, during giardiasis with respect to other infections. Energy pathways including glycolysis and supporting pathways of glyoxylate and dicarboxylate metabolism, and the redox pathway of glutathione metabolism, were upregulated in small intestinal luminal contents and the liver during giardiasis. Metabolomics-16S rRNA genetics integration indicated that populations of three bacterial families-Autopobiaceae (Up), Desulfovibrionaceae (Up), and Akkermanasiaceae (Down)-were most significantly affected across the gut during giardiasis, causing upregulated glycolysis and short-chained fatty acid (SCFA) metabolism. In particular, the perturbed Akkermanasiaceae population seemed to cause oxidative stress responses along the gut-liver axis. Overall, the systems biology approach applied in this study highlighted that the effects of host-parasite-microbiome biochemical interactions extended beyond the gut ecosystem to the gut-liver axis. These findings form the first steps in a comprehensive comparison to ascertain the major molecular and biochemical contributors of host-parasite interactions and contribute towards the development of biomarker discovery and precision health solutions for apicomplexan infections.

Patterns of enteric infections in a population-wide cohort study of sequelae, British Columbia, Canada

We assessed patterns of enteric infections caused by 14 pathogens, in a longitudinal cohort study of sequelae in British Columbia (BC) Canada, 2005-2014. Our population cohort of 5.8 million individuals was followed for an average of 7.5 years/person; during this time, 40 523 individuals experienced 42 308 incident laboratory-confirmed, provincially reported enteric infections (96.4 incident infections per 100 000 person-years). Most individuals (38 882/40 523; 96%) had only one, but 4% had multiple concurrent infections or more than one infection across the study. Among individuals with more than one infection, the pathogens and combinations occurring most frequently per individual matched the pathogens occurring most frequently in the BC population. An additional 298 557 new fee-for-service physician visits and hospitalisations for enteric infections, that did not coincide with a reported enteric infection, also occurred, and some may be potentially unreported enteric infections. Our findings demonstrate that sequelae risk analyses should explore the possible impacts of multiple infections, and that estimating risk for individuals who may have had a potentially unreported enteric infection is warranted.

Decreased fecal calprotectin levels in Spondyloarthritis patients colonized by Blastocystis spp

Spondyloarthritis (SpA) is a group of chronic inflammatory systemic diseases mainly characterized by inflammation in the spine and/or peripheral joints. Although a link between SpA-pathogenesis, intestinal inflammation and gut dysbiosis has been proposed, studies have been focused on bacteria-host interactions and very little has been reported regarding intestinal parasites. Here, intestinal parasitic infection of 51 SpA-patients were evaluated and compared to healthy control individuals. No significant differences in the frequency of any parasite between SpA-patients and control individuals were found. Significantly higher levels of fecal calprotectin (FCP) were found in the SpA-patients compared to the control individuals. However, FCP levels were the same when comparing SpA-patients and control individuals, both colonized by Blastocystis spp. On the other hand, when comparing Blastocystis spp. colonized and Blastocystis spp. free SpA-patients, FCP levels were significantly higher in those Blastocystis spp. free. Without ignoring the small sample size as a study limitation, the results showed that in the SpA-patients colonized by Blastocystis spp., the FCP levels were significantly lower than those in the Blastocystis spp. free group and comparable to those in the control group. These findings seem to suggest a relationship between Blastocystis spp. and intestinal inflammation in SpA-patients, but studies intended to explore that interaction specifically should be designed.

Evaluation of clinical and paraclinical findings in patients with reactive arthritis caused by giardiasis: A systematic review

INTRODUCTION

The aim of this study was to systematically review the clinical and paraclinical findings in patients with reactive arthritis (ReA) caused by giardiasis.

METHODS

In this study, papers describing ReA in patients with giardiasis were found after searching in international databases including MEDLINE/PubMed, Web of Science, Scopus, and ScienceDirect up to 2021. Google Scholar was also searched to find more articles.

RESULTS

Finally, 16 studies met the inclusion criteria with reporting 115 patients, ranging in age from 19 months to 49 years. This disease was more reported in children and adolescents than adults. The most frequently involved joints with arthritis were the knee and ankle followed by the hip, wrist, elbow, shoulder, axial skeleton, metatarsophalangeal, and proximal interphalangeal. The most common extra-articular symptoms included diarrhea, allergic symptoms, and abdominal pain.

CONCLUSION

The signs and symptoms of ReA caused by giardiasis can be various, from moderate to severe manifestations. Also, they can be similar to some other diseases, so it is recommended that physicians and specialists have more knowledge about this disease to treat patients with a correct diagnosis.

Taxonomy and molecular epidemiology of Cryptosporidium and Giardia - a 50 year perspective (1971-2021)

The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing tools has facilitated the expanding range of named species. Currently at least 44 Cryptosporidium spp. and >120 genotypes, and nine Giardia spp., are recognised. Many of these Cryptosporidium genotypes will likely be described as species in the future. The phylogenetic placement of Cryptosporidium at the genus level is still unclear and further research is required to better understand its evolutionary origins. Zoonotic transmission has long been known to play an important role in the epidemiology of cryptosporidiosis and giardiasis, and the development and application of next generation sequencing tools is providing evidence for this. Comparative whole genome sequencing is also providing key information on the genetic mechanisms for host specificity and human infectivity, and will enable One Health management of these zoonotic parasites in the future.

Giardia duodenalis: Biology and Pathogenesis

Giardia duodenalis captured the attention of Leeuwenhoek in 1681 while he was examining his own diarrheal stool, but, ironically, it did not really gain attention as a human pathogen until the 1960s, when outbreaks were reported. Key technological advances, including in vitro cultivation, genomic and proteomic databases, and advances in microscopic and molecular approaches, have led to an understanding that this is a eukaryotic organism with a reduced genome rather than a truly premitochondriate eukaryote. This has included the discovery of mitosomes (vestiges of mitochondria), a transport system with many of the features of the Golgi apparatus, and even evidence for a sexual or parasexual cycle. Cell biology approaches have led to a better understanding of how Giardia survives with two nuclei and how it goes through its life cycle as a noninvasive organism in the hostile environment of the lumen of the host intestine. Studies of its immunology and pathogenesis have moved past the general understanding of the importance of the antibody response in controlling infection to determining the key role of the Th17 response. This work has led to understanding of the requirement for a balanced host immune response that avoids the extremes of an excessive response with collateral damage or one that is unable to clear the organism. This understanding is especially important in view of the remarkable ranges of early manifestations, which range from asymptomatic to persistent diarrhea and weight loss, and longer-term sequelae that include growth stunting in children who had no obvious symptoms and a high frequency of postinfectious irritable bowel syndrome (IBS).

Evolving Epidemiology of Reported Giardiasis Cases in the United States, 1995-2016

BACKGROUND

Giardiasis is the most common intestinal parasitic disease of humans identified in the United States (US) and an important waterborne disease. In the United States, giardiasis has been variably reportable since 1992 and was made a nationally notifiable disease in 2002. Our objective was to describe the epidemiology of US giardiasis cases from 1995 through 2016 using National Notifiable Diseases Surveillance System data.

METHODS

Negative binomial regression models were used to compare incidence rates by age group (0-4, 5-9, 10-19, 20-29, 30-39, 40-49, 50-64, and ≥ 65 years) during 3 time periods (1995-2001, 2002-2010, and 2011-2016).

RESULTS

During 1995-2016, the average number of reported cases was 19 781 per year (range, 14 623-27 778 cases). The annual incidence of reported giardiasis in the United States decreased across all age groups. This decrease differs by age group and sex and may reflect either changes in surveillance methods (eg, changes to case definitions or reporting practices) or changes in exposure. Incidence rates in males and older age groups did not decrease to the same extent as rates in females and children.

CONCLUSIONS

Trends suggest that differences in exposures by sex and age group are important to the epidemiology of giardiasis. Further investigation into the risk factors of populations with higher rates of giardiasis will support prevention and control efforts.

Determining the long-term health burden and risk of sequelae for 14 foodborne infections in British Columbia, Canada: protocol for a retrospective population-based cohort study

INTRODUCTION

Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality, for the population of British Columbia, Canada (~4.7 million).

METHODS AND ANALYSIS

We will conduct a population-based retrospective cohort study of the British Columbia provincial population, over a 10-year study period (1 January 2005 to 31 December 2014). Exposure is defined as a provincially reported illness caused by Clostridium botulinum, Campylobacter, Cryptosporidium, Cyclospora, Giardia, hepatitis A virus, Listeria, non-typhoidal Salmonella spp, Salmonella Typhi, Salmonella Paratyphi, Shiga toxin-producing Escherichia coli, Shigella, Vibrio parahaemolyticus or Yersinia (excluding pestis). We will link individual-level longitudinal data from eight province-wide administrative health and reportable disease databases that include physician visits, hospitalisations and day surgeries, deaths, stillbirths, prescription medications (except those to treat HIV) and reportable foodborne diseases. Using these linked databases, we will investigate the likelihood of various sequelae and death. Hazard models will be used to estimate the risk of outcomes and their association with the type of foodborne infection. Epidemiological analyses will be conducted to determine the progression of illness and the fraction of sequelae attributable to specific foodborne infections. Economic analyses will assess the consequent direct healthcare costs.

ETHICS AND DISSEMINATION

This study has been approved by a University of Waterloo Research Ethics Committee (no 30645), the University of British Columbia Behavioral Research Ethics Board (no H16-00021) and McGill University's Institutional Review Board (no A03-M12-19A). Results will be disseminated via presentations to academics, public health practitioners and knowledge users, and publication in peer-reviewed journals. Where such publications are not open access, manuscripts will also be available via the University of Waterloo's Institutional Repository (https://uwspace.uwaterloo.ca).

Giardia excretory-secretory proteins modulate the enzymatic activities of mast cell chymase and tryptase

BACKGROUND

Mast cells are involved in the host immune response controlling infection with the non-invasive intestinal protozoan parasite Giardia intestinalis. Experimental infections in rodents with G. intestinalis showed increased intestinal expression of mucosal and connective mast cell specific proteases suggesting that both mucosal and connective tissue mast cells are recruited and activated during infection. During infection Giardia excretory-secretory proteins (ESPs) with immunomodulatory capacity are released. However, studies investigating potential interactions between Giardia ESPs and the connective tissue mast cell specific serine proteases, i.e. human chymase and mouse mast cell protease (mMCP)-4 and, human and mouse tryptase (mMCP-6) remain scarce.

RESULTS

We first investigated if soluble Giardia proteins (sGPs), which over-lap extensively in protein content with ESP fractions, from the isolates GS, WB and H3, could induce mast cell activation. sGPs induced a minor activation of bone marrow derived mucosal-like mast cells, as indicated by increased IL-6 secretion and no degranulation. Furthermore, sGPs were highly resistant to degradation by human tryptase while human chymase degraded a 65 kDa sGP and, wild-type mouse ear tissue extracts degraded several protein bands in the 10 to 75 kDa range. In striking contrast, sGPs and ESPs were found to increase the enzymatic activity of human and mouse tryptase and to reduce the activity of human and mouse chymase.

CONCLUSION

Our finding suggests that Giardia ssp. via enhancement or reduction of mast cell protease activity may modulate mast cell-driven intestinal immune responses. ESP-mediated modulation of the mast cell specific proteases may also increase degradation of tight junctions, which may be beneficial for Giardia ssp. during infection.

The "Biology-First" Hypothesis: Functional disorders may begin and end with biology-A scoping review

While it is generally accepted that gastrointestinal infections can cause functional disturbances in the upper and lower gastrointestinal tract-known as postinfectious irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD)-it has still not been widely recognized that such an infection can also initiate functional non-intestinal diseases, and that non-intestinal infections can provoke both intestinal and non-intestinal functional disturbances. We conducted a scoping review of the respective literature and-on the basis of these data-hypothesize that medically unexplained functional symptoms and syndromes following an infection may have a biological (genetic, endocrine, microbiological) origin, and that psychological and social factors, which may contribute to the disease "phenotype," are secondary to this biological cause. If this holds true, then the search for psychological and social theories and factors to explain why one patient develops a chronic functional disorder while another does not is-at least for postinfectious states-misleading and detracts from exploring and identifying the true origins of these essentially biological disorders. The biopsychosocial model may, as the term implies, always begin with biology, also for functional (somatoform) disorders.