High anti-Cryptosporidium parvum IgG seroprevalence in HIV-infected adults in Limpopo, South Africa

Biosensors as early warning detection systems for waterborne Cryptosporidium

Waterborne disease is a global health threat contributing to a high burden of diarrhoeal disease, and growing evidence indicates a prospective increase in incidence coinciding with the profound effects of climate change. A major causative agent of gastrointestinal disease is Cryptosporidium, a protozoan waterborne parasite identified in over 70 countries. Cryptosporidium is a cause of high disease morbidity in children and the immunocompromised with limited treatment options for patients at risk of severe illness. The hardy nature of the organism leads to its persistence in various water sources, with certain water treatment procedures proving inefficient for its complete removal. While diagnostic methods for Cryptosporidium are well-defined in the clinical sphere, detection of Cryptosporidium in water sources remains suboptimal due to low dispersion of organisms in large sample volumes, lengthy processing times and high costs of equipment and reagents. A need for improvement exists to identify the organism as an emerging threat in domestic water systems, and the technological advantages that biosensors offer over current analytical methods may provide a preventative approach to outbreaks of Cryptosporidium. Biosensors are innovative, versatile and adaptable analytical tools that could provide highly sensitive, rapid, on-site analysis needed for Cryptosporidium detection in low-resource settings.

Prevalence and Distribution of Cryptosporidium spp. and Giardia lamblia in Rural and Urban Communities of South Africa

OBJECTIVE

Enteric diseases remain a serious health problem globally. High prevalence is evident in regions with poor socioeconomic conditions, poor sanitation, and inadequate clean water supply, such as South Africa. Designing an effective strategy, however, requires local knowledge, which can be particularly challenging to acquire in low-and middle-income countries. As the first step in this process, we investigated the prevalence and distribution of protozoan parasites Cryptosporidium and Giardia in the rural and urban gastrointestinal clinics of South Africa.

METHODS

A cross-sectional study was conducted to assess the prevalence of enteric parasites Cryptosporidium and G. lamblia in rural and urban communities of South Africa. Stool samples were collected from November 2013 to June 2015 from patients with diarrhea (n=227) and without diarrhea (n=257). DNA was extracted and a diagnostic Taqman qPCR assay was performed to detect these protozoan parasites, which was further confirmed by the Sanger sequencing of a few samples.

RESULTS

Of the 484 stool specimens collected, 34% (166/484) were positive for either Cryptosporidium spp. or Giardia lamblia parasites, with only 5% containing both parasites (22/484). In both study populations, Cryptosporidium was the most prevalent parasite (overall 25%) followed by Giardia (19%).

CONCLUSION

This study discovered that both Giardia and Cryptosporidium parasites might contribute to diarrheal disease in South Africa and are more prevalent in rural communities. Future studies are needed to identify the source of the infection and design appropriate interventions to reduce the burden of the disease.

AMAÇ

Enterik hastalıklar küresel olarak ciddi bir sağlık sorunu olmaya devam etmektedir. Güney Afrika gibi düşük sosyo-ekonomik koşulların, kötü sanitasyonun ve yetersiz temiz su kaynaklarının olduğu bölgelerde yüksek prevalans görülmektedir. Ancak etkili bir strateji tasarlamak için, düşük ve orta gelirli ülkelerde edinilmesi özellikle zor olabilecek yerel bir bilgi gerektirmektedir. Bu süreçte biz ilk adım olarak, Güney Afrika’nın kırsal ve kentsel gastrointestinal kliniklerinde protozoan parazitler Cryptosporidium ve Giardia’nın prevalansını ve dağılımını araştırdık.

YÖNTEMLER

Güney Afrika’nın kırsal ve kentsel topluluklarında Cryptosporidium ve G. lamblia enterik parazitlerinin sıklığını araştırmak için kesitsel bir çalışma yapıldı. İshali olan (n=227) ve olmayan (n=257) hastaların Kasım 2013-Haziran 2015 tarihleri arasında dışkı örnekleri toplandı. DNA ekstrakte edildi ve bu protozoan parazitleri saptamak için tanısal bir Taqman qPCR tahlili kullanılarak, birkaç örnek Sanger dizilimi ile daha da doğrulandı.

BULGULAR

Toplanan 484 dışkı örneğinin %34’ü (166/484) Cryptosporidium spp. veya Giardia lamblia parazitleri için pozitifti ve örneklerin sadece %5’i her iki paraziti de içeriyordu (22/484). Her iki çalışma popülasyonunda da Cryptosporidium en yaygın parazitti (toplam %25) ve bunu Giardia (%19) izledi.

SONUÇ

Bu çalışma, hem Giardia hem de Cryptosporidium parazitlerinin Güney Afrika’daki ishal hastalığına katkıda bulunabileceğini ve kırsal topluluklarda daha yaygın olduğunu göstermiştir. Hem enfeksiyonun kaynağını belirlemek hem de hastalığın yükünü azaltmak için uygun müdahaleleri tasarlamak için gelecekteki çalışmalara ihtiyaç vardır.

A meta-analysis of Cryptosporidium species in humans from southern Africa (2000-2020)

Abstract

The epidemiology of cryptosporidiosis in southern Africa is largely unknown. The disease is associated with diarrhea and nutritional deficiencies, leading to severe morbidity and mortality among immune-compromised patients. This study aimed to assess the pooled prevalence of Cryptosporidium spp. infection among immune-compromised humans in southern Africa over the past 20 years. Reports of Cryptosporidium spp. infection in humans published between 2000 and 2020 using Google Scholar, PubMed, Ovid Medline, African Journal Online (AJOL), and Web of Science literature databases were obtained. Inclusion criteria of sorted articles for Cryptosporidium spp. infection were standardized using preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. A total of 22 eligible studies were sorted for meta-analysis. Overall prevalence of Cryptosporidium spp. infection in southern African countries with reports was 16.8% (95% CI 9.7-25.3). Sub-group analysis showed a pooled prevalence of 25.2, 20.5, and 17.9% among HIV/AIDS patients, children, and diarrhoeic individuals, respectively. Pooled prevalence was highest in South Africa and lowest in Zimbabwe across examined individuals. The pooled prevalence of Cryptosporidium spp. infections in diarrhoeic patients was highest in individuals from Botswana (17.6%) which is significantly different (Χ ² = 9.337; P = 0.002) from South Africans (12.7%). South African individuals with HIV/AIDS showed the highest pooled prevalence of Cryptosporidium infections than other countries. The high prevalence of Cryptosporidium spp. infections among immune-compromised patients in southern Africa showed that the pathogen is of significant importance in this region. Continuous studies on the genetic characterization of Cryptosporidium spp. isolates and associated risk factors are needed across southern Africa to identify the predominant subtypes in humans.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-021-01436-4.

Cryptosporidiosis in HIV-positive patients and related risk factors: A systematic review and meta-analysis

Cryptosporidium is one of the major causes of diarrhea in HIV-positive patients. The aim of this study is to systematically review and meta-analyze the prevalence of Cryptosporidium in these patients. PubMed, Science Direct, Google Scholar, Web of Science, Cochrane and Ovid databases were searched for relevant studies dating from the period of 1 January 2000 to 31 December 2017. Data extraction for the included studies was performed independently by two authors. The overall pooled prevalence was calculated and subgroup analysis was performed on diagnostic methods, geographical distribution and study population. Meta-regression was performed on the year of publication, proportion of patients with diarrhea, and proportion of patients with CD4 < 200 cells/mL. One hundred and sixty-one studies and 51,123 HIV-positive participants were included. The overall pooled prevalence of Cryptosporidium infection in HIV-positive patients was 11.2% (CI95%: 9.4%–13.0%). The pooled prevalence was estimated to be 10.0% (CI95%: 8.4%–11.8%) using staining methods, 13.5% (CI95%: 8.9%–19.8%) using molecular methods, and 26.3% (CI95%: 15.0%–42.0%) using antigen detection methods. The prevalence of Cryptosporidium in HIV patients was significantly associated with the country of study. Also, there were statistical differences between the diarrhea, CD4 < 200 cells/mL, and antiretroviral therapy risk factors with Cryptosporidiosis. Thus, Cryptosporidium is a common infection in HIV-positive patients, and safe water and hand-hygiene should be implemented to prevent cryptosporidiosis occurrence in these patients.

Widespread occurrence of Cryptosporidium infections in patients with HIV/AIDS: Epidemiology, clinical feature, diagnosis, and therapy

Cryptosporidium infection is a serious threat for HIV/AIDS patients, causing severe diarrhea and even death. The overall prevalence of Cryptosporidium in HIV/AIDS patients was calculated as approximately 8.69% (7,799/89,724), with higher prevalence observed in individuals with diarrhea, individuals with low CD4⁺ T-lymphocyte counts, and antiretroviral therapy-naïve individuals. Cryptosporidium infection was not significantly associated with patient age or gender, national development levels, or continent of residence. Over the period from 2007 to 2017, Cryptosporidium prevalence was 10.09% (3,282/32,517); this figure was higher than that observed in each of the previous observation periods (1985-1995 and 1996-2006), suggesting that the prevalence of cryptosporidiosis has been increasing over time in HIV/AIDS patients. Ten Cryptosporidium species and genotypes have been identified from 1,252 isolates, with C. hominis, C. parvum, and C. meleagridis accounting for 93.53% of infections. Five subtypes each of C. hominis (Ia, Ib, Id, Ie, and If), C. parvum (IIa to IIe), and C. meleagridis (IIIa to IIIe) have been described by sequence analyses of the 60-kDa glycoprotein (gp60) gene. Variation in the clinical manifestations observed in HIV/AIDS patients might be attributed to infection by different Cryptosporidium species, genotypes and subtypes, as well as different sites of infection. New molecular and immunological diagnostic techniques are in development or already commercially available. High-throughput screening methods for development of new or repurposed therapeutics as well as novel parasite genetic manipulation strategies offer hope for improving human cryptosporidiosis therapies. Painstaking efforts by researchers as well as support from governments and funding agencies will be required to make lasting achievements in this field.

Increased Urinary Trimethylamine N-Oxide Following Cryptosporidium Infection and Protein Malnutrition Independent of Microbiome Effects

Cryptosporidium infections have been associated with growth stunting, even in the absence of diarrhea. Having previously detailed the effects of protein deficiency on both microbiome and metabolome in this model, we now describe the specific gut microbial and biochemical effects of Cryptosporidium infection. Protein-deficient mice were infected with Cryptosporidium parvum oocysts for 6-13 days and compared with uninfected controls. Following infection, there was an increase in the urinary excretion of choline- and amino-acid-derived metabolites. Conversely, infection reduced the excretion of the microbial-host cometabolite (3-hydroxyphenyl)propionate-sulfate and disrupted metabolites involved in the tricarboxylic acid (TCA) cycle. Correlation analysis of microbial and biochemical profiles resulted in associations between various microbiota members and TCA cycle metabolites, as well as some microbial-specific degradation products. However, no correlation was observed between the majority of the infection-associated metabolites and the fecal bacteria, suggesting that these biochemical perturbations are independent of concurrent changes in the relative abundance of members of the microbiota. We conclude that cryptosporidial infection in protein-deficient mice can mimic some metabolic changes seen in malnourished children and may help elucidate our understanding of long-term metabolic consequences of early childhood enteric infections.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model

Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (10⁶ oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3⁺CD8⁺CD103⁺ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children.

Cryptosporidium attributable morbidities in malnourished children are increasingly recognized. Exactly how malnutrition interferes with host mucosal immunity to diarrheal pathogens and mucosal vaccine responses remains unclear. Dissecting these interactions in an experimental model of cryptosporidiosis can uncover new insights into novel therapeutic approaches against a pathogen for which effective therapies and vaccines are currently unavailable. We demonstrate that although malnutrition diminishes baseline (primary) Th1-type mucosal immunity these deficits can be partially overcome via non-specific mucosal strategies (S. Typhi and CpG) and completely restored after a sub-clinical (low-dose) exposure to viable C. parvum. These results add insight into preventive strategies to help alleviate Cryptosporidium-specific diarrhea in children in low-resource settings and abrogate prolonged post-infection sequelae.

Therapeutic effects of acetylspiramycin and garlicin on cryptosporidiosis among drug users

Cryptosporidiosis affects humans of all ages, particularly malnourished children and those with compromised immune systems such as HIV/AIDS. This study investigated the therapeutic effects of acetylspiramycin and garlicin on Cryptosporidium infection in institutionalized male drug users receiving rehabilitative treatment. Examination of stool specimens from 903 drug users via modified acid-fast bacilli staining resulted in 172 positive cases. Among them 151 subjects consented to participate in a randomized trial of acetylspiramycin and garlicin in four groups: acetylspiramycin plus garlicin, acetylspiramycin only, garlicin only, and placebo control. The cryptosporidiosis rate was higher in younger subjects with longer drug use history than subjects who are older with shorter history of drug use. After two segments of treatments, 76.2% of the cases achieved negative test results, with the four groups achieving the rates of 92.1%, 76.7%, 72.2%, and 61.8%, respectively (χ(2) = 9.517, P = 0.023). These results indicate clinical potential of garlicin in conjunction with acetylspiramycin in treating cryptosporidiosis.

Prevalence and Genotyping of Cryptosporidium Infection in Pet Parrots in North China

Cryptosporidiosis is a worldwide zoonosis caused by Cryptosporidium spp., sometimes leading to severe diarrhea in humans and animals. In the present study, 311 parrots, belonging to four species, namely, Budgerigars (Melopsittacus undulatus), Lovebirds (Agapornis sp.), Alexandrine parakeets (Psittacula eupatria), and Cockatiel (Nymphicus hollandicus), from Beijing and Weifang cities, were examined for Cryptosporidium spp. infection. Blood samples of each bird were examined using enzyme linked immunosorbent assay (ELISA) and fecal samples were examined by Sheather's sugar flotation technique. Prevalence of Cryptosporidium infection were 3.22% (10/311) and 0.64% (2/311) by ELISA and Sheather's sugar flotation technique, respectively. Seroprevalence of Cryptosporidium infection in different breeds varied from 0 to 15.39%. Sequencing analysis showed that both positive samples from fecal samples belonged to Cryptosporidium avian genotype V. This is the first report of Cryptosporidium avian genotype V in Budgerigars. The results of the present study provided foundation-data for prevention and control of cryptosporidiosis in pet birds in China.