Risk factors leading to Cryptosporidium infection in men who have sex with men

Cryptosporidium-induced acute kidney injury in a patient with acquired immunodeficiency syndrome

Cryptosporidium is a pathogen that can cause infectious enteritis especially in immunocompromised patients. Acute kidney injury, electrolyte imbalance, and acid-base disorders may occur as a result of high volumes of intestinal fluid loss, which has not been previously reported to be a common manifestation of cryptosporidiosis. Numerous antigen detection methods can be used to ensure early diagnosis of Cryptosporidium infection, which is crucial to prevent morbidities. We report a unique case of cryptosporidiosis in a 33-year-old male patient with acute kidney injury and profound hypokalemia, hyponatremia, hypocalcemia, hypophosphatemia, hypomagnesemia, and metabolic acidosis. Following the initiation of antiretroviral therapy to human immunodeficiency virus, the patient's symptoms improved and he recovered fully from kidney injury and electrolyte imbalance, highlighting the importance of early antiretroviral therapy.

Factors associated with Cryptosporidium in men who have sex with men: A systematic review

BACKGROUND

Cryptosporidium parasites are an important cause of diarrhoea globally and sexual transmission may occur in men who have sex with men (MSM). We aimed to systematically review the literature to explore any factors associated with transmission of Cryptosporidium in MSM to provide insight for future guidelines and public health strategies.

METHODS

We searched MEDLINE, Embase, CINAHL and Web of Science for manuscripts published up to July 2023. A primary author conducted an initial screen of abstracts and full text eligibility, and risk of bias was assessed independently by two authors using the Joanna Briggs Institute critical appraisal tools. We used the nine-point synthesis without meta-analysis method to synthesise narrative data. The review was registered on PROSPERO (CRD42023374279).

RESULTS

Six manuscripts were included in the final review from the USA (n = 3), Europe (n = 1) and Australia (n = 2) and were case series (n = 2), cross sectional (n = 2) and case control studies (n = 2) published between 1984 and 2021 and overall there were 1582 cases of Cryptosporidium in MSM. We identified demographic factors (living with HIV, younger age [<30 years old], geographical areas [Southern Europe v Northern Europe], previous Treponema pallidum, previous Entamoeba histolytica) and behavioural factors (recreational drug use, higher number of sexual partners and MSM attending sex on premises venues with spa/sauna) associated with Cryptosporidium in MSM.

CONCLUSIONS

Despite a small number of manuscripts in this review, we identified demographic and behavioural factors associated with Cryptosporidium in MSM. These data will provide insight for public health interventions for future outbreaks of Cryptosporidium in MSM.

Enteric Infections in Men Who Have Sex With Men

BACKGROUND

Enteric pathogens are often associated with exposure to food, water, animals, and feces from infected individuals. However, in sexual networks of men who have sex with men (MSM), transmission of enteric pathogens may occur during direct or indirect oral-anal contact.

METHODS

We performed a scoping review of the literature for studies prior to July 2019 with key terms for gastrointestinal syndromes ("proctitis," "enteritis," "proctocolitis"), enteric pathogens or sexually transmitted infections (STIs), and outbreaks using multiple electronic databases.

RESULTS

We identified 5861 records through database searches, bibliography reviews, and keyword searches, of which 117 references were included in the pathogen-specific reviews.

CONCLUSIONS

The strength of observational data describing enteric pathogens in MSM and possible sexual transmission of enteric pathogens varies by pathogen; however, a robust body of literature describes the sexual transmission of Campylobacter, Giardia lamblia, and Shigella (particularly antimicrobial-resistant strains) in sexual networks of MSM. Providers are encouraged to consider enteritis or proctocolitis in MSM as possibly having been sexually transmitted and encourage targeted STI testing. Risk/harm reduction and prevention messages should also be incorporated, though there is an acknowledged paucity of evidence with regards to effective strategies. Further research is needed to understand the transmission and prevention of enteric pathogens in MSM.

A scoping review of risk factors and transmission routes associated with human giardiasis outbreaks in high-income settings

The flagellated pathogen Giardia duodenalis is one of the leading causes of parasitic gastrointestinal illness worldwide. In many higher income countries, such as the United Kingdom, the disease is often perceived as being travel-related, likely leading to the under-reporting of sporadic cases and outbreaks. A summary of the literature describing outbreaks and risk factors in higher income countries is necessary to improve our understanding of this pathogen and identify existing knowledge gaps. Initial literature searches were carried out in September 2016 and updated at regular intervals until November 2021, using appropriate search terms in Medline, Embase and PubMed databases. A total of 75 papers met the inclusion criteria, revealing that the consumption of contaminated water and contact with young children of diaper-wearing age were the most common transmission routes leading to outbreaks of giardiasis. Of the ten studies where food was primarily associated with outbreaks, food handlers accounted for eight of these. Another reported transmission route was direct contact with fecal material, which was reported in six studies as the primary transmission route. Travel-associated giardiasis was considered the sole transmission route in two studies, whereas multiple transmission routes contributed to giardiasis outbreaks in eleven studies. The evidence around zoonotic transmission was less clear and hampered by the lack of robust and regularly applied parasite molecular typing techniques. This literature review summarizes the findings of Giardia outbreak investigations and epidemiological studies in high-income countries. Transmission routes are identified and discussed to highlight the associated risk factors. These data also indicate gaps in our current knowledge that include the need for robust, in-depth molecular studies and have underscored the importance of water as a transmission route for Giardia cysts. These future molecular studies will improve our understanding of Giardia epidemiology and transmission pathways in higher income countries to prevent spread of this significantly under-reported pathogen.

Current pharmacotherapy of cryptosporidiosis: an update of the state-of-the-art

Introduction: Cryptosporidiosis has emerged as a major cause of diarrheal disease worldwide. It has especially serious health consequences for young, malnourished children living in endemic areas and for individuals with highly impaired T-cell function, such as HIV-positive individuals with low CD4 counts or immunosuppressed solid-organ transplant recipients.Areas covered: A selective literature search using PubMed was performed to review the available therapeutics to treat cryptosporidiosis, as well as related advances in drug development.Expert opinion: The only FDA-approved antiparasitic treatment in immunocompetent patients is nitazoxanide; however, it has failed to demonstrate convincing effectiveness among HIV-positive patients, immunosuppressed individuals and malnourished children. Thus, restoring HIV-positive patients' cellular immune response through effective antiretroviral therapy (ART), or reducing or changing immunosuppressive drugs, is important. Several new targets have been identified for chemotherapy, and the development of drugs for these targets has progressed, including parasite kinases, nucleic acid synthesis and processing, proteases and lipid metabolism. Candidate drugs that have been shown to be effective and safe in a neonatal calf model will most likely constitute the next advance for clinical trials in humans. However, developing an effective and inexpensive vaccination, as well as complementing structural preventive measures, would most decisively reduce the global cryptosporidiosis burden.

Epidemiology of Cryptosporidiosis, New York City, New York, USA, 1995-20181

Cryptosporidiosis is a parasitic diarrheal infection that is transmitted by the fecal-oral route. We assessed trends in incidence and demographic characteristics for the 3,984 cases diagnosed during 1995-2018 in New York City, New York, USA, and reported to the New York City Department of Health and Mental Hygiene. Reported cryptosporidiosis incidence decreased with HIV/AIDS treatment rollout in the mid-1990s, but the introduction of syndromic multiplex diagnostic panels in 2015 led to a major increase in incidence and to a shift in the demographic profile of reported patients. Incidence was highest among men 20-59 years of age, who consistently represented most (54%) reported patients. In addition, 30% of interviewed patients reported recent international travel. The burden of cryptosporidiosis in New York City is probably highest among men who have sex with men. Prevention messaging is warranted for men who have sex with men and their healthcare providers, as well as for international travelers.

Use of gender distribution in routine surveillance data to detect potential transmission of gastrointestinal infections among men who have sex with men in England

Detecting gastrointestinal (GI) infection transmission among men who have sex with men (MSM) in England is complicated by a lack of routine sexual behavioural data. We investigated whether gender distributions might generate signals for increased transmission of GI pathogens among MSM. We examined the percentage male of laboratory-confirmed patient-episodes for patients with no known travel history for 10 GI infections of public health interest in England between 2003 and 2013, stratified by age and region. An adult male excess was observed for Shigella spp. (annual maximum 71% male); most pronounced for those aged 25-49 years and living in London, Brighton and Manchester. An adult male excess was observed every year for Entamoeba histolytica (range 59.8-76.1% male), Giardia (53.1-57.6%) and Campylobacter (52.1-53.5%) and for a minority of years for hepatitis A (max. 69.8%) and typhoidal salmonella (max. 65.7%). This approach generated a signal for excess male episodes for six GI pathogens, including a characterised outbreak of Shigella among MSM. Stratified analyses by geography and age group were consistent with MSM transmission for Shigella. Optimisation and routine application of this technique by public health authorities elsewhere might help identify potential GI infection outbreaks due to sexual transmission among MSM, for further investigation.

Exposures associated with infection with Cryptosporidium in industrialised countries: a systematic review protocol

BACKGROUND

Cryptosporidium is a protozoan parasite of humans and other animals worldwide and is one of the greatest contributors to human diarrhoeal illness. Transmission can occur indirectly via contaminated food or water, or directly via contact with animals or other infected people. Risk exposures are often identified from outbreak investigations, but a subset of cases remains unexplained, and sources for sporadic disease and pathways to infection are still unclear. Given the few systematic syntheses of reported evidence in industrialised populations, the aim of this review is to consolidate the literature to describe exposures associated with human cryptosporidiosis in industrialised countries, specifically including the UK, and describe any differences between outbreak-associated and sporadic disease.

METHODS/DESIGN

Where relevant, methods will follow the recommendations made in the Cochrane Handbook for Systematic Reviews of Interventions. Three steps will be used to identify the literature including electronic database searching using PubMed, Scopus, Embase and Web of Science; reference list trawling; and an exploration of the grey literature. Screening of results will be undertaken by two reviewers using pre-defined criteria. Studies conducted in industrialised countries and reporting on human subjects will be included. All observational studies will be included where they report exposures and relevant quantitative results. Data will be extracted using a standardised form. Study quality will be assessed using the ROBINS-I tool. Data will be summarised presenting the papers' main findings including population under study, outcomes, and exposures, and whether these were considered outbreak or sporadic cases. A narrative summary will also be included. Where populations are appropriate, available data will be pooled in a meta-analysis combining the significant exposures across studies.

DISCUSSION

This review aims to consolidate the evidence for transmission routes and exposures for Cryptosporidium in industrialised countries, with particular reference to how these may apply to the UK. In addition, the review will seek to describe differences between outbreak and sporadic cases. This will help to identify those most vulnerable, highlighting pathways where interventions and public health response may be appropriate.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO number CRD42017056589 .

Opportunistic and non-opportunistic intestinal parasites in HIV/ AIDS patients in relation to their clinical and epidemiological status in a specialized medical service in Goiás, Brazil

Patients infected with the Human Immunodeficiency Virus (HIV) often have opportunistic infections, among which strongyloidiasis and coccidiosis are the most common parasitic infections that aggravate their health status. This study examined the prevalence of intestinal parasites, particularly of Strongyloides stercoralis and intestinal coccidia in patients with the Human Immunodeficiency Virus (HIV)/ Acquired Immunodeficiency Syndrome (AIDS) who were treated at the Specialized Assistance Service (SAE) of Jataí, State of Goiás, Brazil, and analyzed its correlation with clinical, laboratory, and socio-epidemiological parameters. A total of 270 stool samples were analyzed by the Lutz technique, Rugai's method, Agar Plate Culture, Ritchie's method and specific staining, Ziehl-Neelsen modified technique, Kinyoun's method and the rapid safranin method. The prevalence of intestinal parasites was 28.88% including 3.8% of S. stercoralis, Cryptosporidium sp. and Cystoisospora belli. There was a significant positive correlation between intestinal parasites and the clinical status and the use of antiretroviral therapy (ART), smoking, CD4+ lymphocyte counts and sexual orientation. In conclusion, the widespread use of antiretroviral therapy and health assistance contributed to the low prevalence of S. stercoralis and coccidiosis in patients with HIV/ AIDS who were followed up at the SAE.

Association between enteric protozoan parasites and gastrointestinal illness among HIV- and tuberculosis-infected individuals in the Chowke district, southern Mozambique

Human immune deficiency virus (HIV) and tuberculosis (TB) infections remain major public health issues globally, particularly in sub-Saharan Africa. Impairment of both cell-mediated and humoral immunity by HIV and/or TB infections may limit the host's defences against other pathogens, including the diarrheagenic protozoan Cryptosporidium spp., Giardia intestinalis, and Entamoeba histolytica. During September-December 2015 a cross-sectional study was conducted to assess the prevalence and molecular diversity of these enteric parasites among HIV- and/or TB-infected patients at a medical reference centre in Chowke district, southern Mozambique. A total of 99 stool specimens were initially screened by direct microscopy and further confirmed and characterised by molecular methods. DNA sequence analyses of the genes encoding the small subunit ribosomal RNA and the 60-kDa glycoprotein were used for the typing and sub-typing of Cryptosporidium isolates, respectively. G. intestinalis-positive isolates by real-time PCR were subsequently typed at the glutamate dehydrogenase locus. Differential diagnosis of E. histolytica/dispar was achieved by real-time PCR. G. intestinalis (8.1%) was the enteric protozoan more frequently detected, followed by Cryptosporidium spp. (7.1%), and Entamoeba histolytica/dispar (6.1%). Two HIV-infected (but not TB-infected) patients harbour G. intestinalis and Cryptosporidium spp. co-infections. Two (29%) G. intestinalis isolates were successfully characterised, revealing the presence of known AII and novel BIV genotypes. Four (57%) Cryptosporidium isolates were unmistakeable assigned to C. hominis, identifying two (IbA10G2 and IdA22) sub-types. Cryptosporidium infections were not associated to diarrhoea in HIV-positive patients, probably because improved immune function in the affected individuals due to antiretroviral therapy. G. intestinalis was considered a non-opportunistic pathogen, whereas the presence of E. histolytica could not be confirmed by molecular methods. Based on their common presence in the studied clinical population, we recommend the effective diagnosis and treatment of these enteropathogens for improving the management of HIV and TB patients.

Cryptosporidium pathogenicity and virulence

Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence.

Risk factor analysis and spatiotemporal CART model of cryptosporidiosis in Queensland, Australia

BACKGROUND

It remains unclear whether it is possible to develop a spatiotemporal epidemic prediction model for cryptosporidiosis disease. This paper examined the impact of social economic and weather factors on cryptosporidiosis and explored the possibility of developing such a model using social economic and weather data in Queensland, Australia.

METHODS

Data on weather variables, notified cryptosporidiosis cases and social economic factors in Queensland were supplied by the Australian Bureau of Meteorology, Queensland Department of Health, and Australian Bureau of Statistics, respectively. Three-stage spatiotemporal classification and regression tree (CART) models were developed to examine the association between social economic and weather factors and monthly incidence of cryptosporidiosis in Queensland, Australia. The spatiotemporal CART model was used for predicting the outbreak of cryptosporidiosis in Queensland, Australia.

RESULTS

The results of the classification tree model (with incidence rates defined as binary presence/absence) showed that there was an 87% chance of an occurrence of cryptosporidiosis in a local government area (LGA) if the socio-economic index for the area (SEIFA) exceeded 1021, while the results of regression tree model (based on non-zero incidence rates) show when SEIFA was between 892 and 945, and temperature exceeded 32°C, the relative risk (RR) of cryptosporidiosis was 3.9 (mean morbidity: 390.6/100,000, standard deviation (SD): 310.5), compared to monthly average incidence of cryptosporidiosis. When SEIFA was less than 892 the RR of cryptosporidiosis was 4.3 (mean morbidity: 426.8/100,000, SD: 319.2). A prediction map for the cryptosporidiosis outbreak was made according to the outputs of spatiotemporal CART models.

CONCLUSIONS

The results of this study suggest that spatiotemporal CART models based on social economic and weather variables can be used for predicting the outbreak of cryptosporidiosis in Queensland, Australia.

Sexual transmission of intestinal parasites in men who have sex with men

Direct oral-anal sexual contact is a common practice among men who have sex with men (MSM) and is implicated in the transmission of various enteric pathogens including intestinal parasites. The present study reviewed data on the sexual transmission of intestinal parasites among MSM, and highlighted advances in the diagnosis of such infections. The emergence and spread of intestinal parasites is of public health concern particularly in the homosexual community. Intestinal parasitic infection should be considered in the differential diagnosis of gastrointestinal disease in this population. Combination of traditional diagnostic procedures with implementation of testing based on novel molecular methods in the accurate identification of intestinal parasites is important so that early intervention and control of infection is facilitated.

Spatial analysis of notified cryptosporidiosis infections in Brisbane, Australia

PURPOSE

This study explored the spatial distribution of notified cryptosporidiosis cases and identified major socioeconomic factors associated with the transmission of cryptosporidiosis in Brisbane, Australia.

METHODS

We obtained the computerized data sets on the notified cryptosporidiosis cases and their key socioeconomic factors by statistical local area (SLA) in Brisbane for the period of 1996 to 2004 from the Queensland Department of Health and Australian Bureau of Statistics, respectively. We used spatial empirical Bayes rates smoothing to estimate the spatial distribution of cryptosporidiosis cases. A spatial classification and regression tree (CART) model was developed to explore the relationship between socioeconomic factors and the incidence rates of cryptosporidiosis.

RESULTS

Spatial empirical Bayes analysis reveals that the cryptosporidiosis infections were primarily concentrated in the northwest and southeast of Brisbane. A spatial CART model shows that the relative risk for cryptosporidiosis transmission was 2.4 when the value of the social economic index for areas (SEIFA) was over 1028 and the proportion of residents with low educational attainment in an SLA exceeded 8.8%.

CONCLUSIONS

There was remarkable variation in spatial distribution of cryptosporidiosis infections in Brisbane. Spatial pattern of cryptosporidiosis seems to be associated with SEIFA and the proportion of residents with low education attainment.

Evaluation of a screening test for detection of giardia and cryptosporidium parasites

The Giardia/Cryptosporidium Chek test (TechLab, Inc.), a screening test for Giardia and Cryptosporidium, was evaluated with 136 fecal samples. Using the results of the Giardia II test and Cryptosporidium II test as gold standards, it was 98.4% sensitive and 100% specific and had positive and negative predictive values of 98.7% and 99.3%.

The zoonotic transmission of Giardia and Cryptosporidium

The molecular characterisation of Giardia and Cryptosporidium has given rise to a more epidemiological meaningful and robust taxonomy. Importantly, molecular tools are now available for 'typing' isolates of the parasites directly from clinical and environmental samples. As a consequence, information on zoonotic potential has been obtained although the frequency of zoonotic transmission is still poorly understood. Analysis of outbreaks and case-control studies, especially when coupled with genotyping data, is slowly providing information on the public health significance of zoonotic transmission. Such studies support the hypothesis that Cryptosporidium hominis is spread only between humans but that the major reservoir for Cryptosporidium parvum is domestic livestock, predominantly cattle, and that direct contact with infected cattle is a major transmission pathway along with indirect transmission through drinking water. The situation is less clearcut for Giardia duodenalis but the evidence does not, in general, support zoonotic transmission as a major risk for human infections. However, for both parasites there is a need for molecular epidemiological studies to be undertaken in well-defined foci of transmission in order to fully determine the frequency and importance of zoonotic transmission.