Cryptosporidium hominis infection of the human respiratory tract

The risk of wild birds contaminating source water with zoonotic Cryptosporidium and Giardia is probably overestimated

Cryptosporidium and Giardia are important waterborne protozoan parasites that are resistant to disinfectants commonly used for drinking water. Wild birds, especially wild migratory birds, are often implicated in the contamination of source and wastewater with zoonotic diseases, due to their abundance near water and in urban areas and their ability to spread enteric pathogens over long distances. This review summarises the diversity of Cryptosporidium and Giardia in birds, with a focus on zoonotic species, particularly in wild and migratory birds, which is critical for understanding zoonotic risks. The analysis revealed that both avian-adapted and zoonotic Cryptosporidium species have been identified in birds but that avian-adapted Cryptosporidium species dominate in wild migratory birds. Few studies have examined Giardia species and assemblages in birds, but the non-zoonotic Giardia psittaci and Giardia ardeae are the most commonly reported species. The identification of zoonotic Cryptosporidium and Giardia in birds, particularly C. parvum and G. duodenalis assemblages A and B in wild migratory birds, is likely due to mechanical carriage or spillback from birds co-grazing pastures contaminated with C. parvum from livestock. Therefore, the role of wild migratory birds in the transmission of zoonotic Cryptosporidium and Giardia to source water is likely overestimated. To address knowledge gaps, it is important to conduct more extensive studies on the prevalence of Cryptosporidium and Giardia in a broader range of migratory wild birds. There is also a need to investigate the extent to which zoonotic infections with C. hominis/C. parvum and G. duodenalis assemblages A and B are mechanical and/or transient, and to assess the load and viability of zoonotic oo/cysts shed in avian faeces. Understanding the contribution of birds to zoonoses is essential for effective disease surveillance, prevention, and control.

Respiratory cryptosporidiosis detected by commercial multiplex-PCR in immunosuppressed pediatric patients

We report the off-label use of a commercial gastrointestinal protozoa multiplex-PCR panel for bronchoalveolar lavage samples, detecting respiratory cryptosporidiosis in 2 immunocompromised pediatric patients. We suggest that implying this readily available assay in cases in which systemic cryptosporidiosis is suspected, may widen our understanding regarding this rarely reported syndrome.

A Pilot Study on the Evaluation of Cryptosporidium Infection in Patients with Lung Cancer; Respiratory Cryptosporidiosis

Lung carcinoma is one the most common cancer and the leading cause of cancer-related death worldwide. Increasing evidences have shown that Cryptosporidium spp., an opportunistic parasite, is associated with cancers, causing a life-threatening infection. The most common clinical form of Cryptosporidium is intestinal infection. However, respiratory cryptosporidiosis has been rarely documented although the parasite infects respiratory epithelium cells as well as GIS epithelium cells. To evaluate respiratory cryptosporidiosis in patients with lung cancer, we investigated Cryptopsoridium spp. in patients with lung cancer (n=69) by comparing with healthy groups (n=40). Sputum and stool samples were tested by microscopic examination and polymerase chain reaction. Two cancer patients were diagnosed with respiratory cryptosporidiosis (2.9%), by PCR examination of the sputum samples. Cryptopsoridium spp. was detected in the stool sample of one patient (1.5%), and two healthy individuals (5.4%), by PCR and microscopy. Firstly, respiratory cryptosporidiosis was documented in two patients with lung cancer. Cryptosporidium is an important agent of respiratory tract infection as well as GIS infection, in cancer patients. These new findings highlight the molecular prevalence of Cryptosporidium spp., an opportunistic infection, in patients with lung cancer, and respiratory cryptosporidiosis should also be considered when patients have respiratory symptoms.

Respiratory cryptosporidiosis in Malawian children with diarrheal disease

Background

Respiratory cryptosporidiosis has been documented in children with diarrhea. We sought to describe the dynamics of respiratory involvement in children hospitalized with gastrointestinal (GI) diarrheal disease.

Methods

We conducted a prospective, observational longitudinal study of Malawian children 2–24 months hospitalized with diarrhea. Nasopharyngeal (NP) swabs, induced sputum and stool specimens were collected. Participants that were positive by Cryptosporidium PCR in any of the three compartments were followed up with fortnightly visits up to 8 weeks post-enrollment.

Results

Of the 162 children recruited, participants had mild-moderate malnutrition (mean HAZ -1.6 (SD 2.1)), 37 (21%) were PCR-positive for Cryptosporidium at enrollment (37 stool, 11 sputum, and 4 NP) and 27 completed the majority of follow-up visits (73%). Cryptosporidium was detected in all compartments over the 4 post-enrollment visits, most commonly in stool (100% at enrollment with mean cycle thresholds (Ct) of 28.8±4.3 to 44% at 8 weeks with Ct 29.9±4.1), followed by sputum (31% at enrollment with mean Ct 31.1±4.4 to 20% at 8 weeks with Ct 35.7±2.6), then NP (11% with mean Ct 33.5±1.0 to 8% with Ct 36.6±0.7). Participants with Cryptosporidium detection in both the respiratory and GI tract over the study period reported respiratory and GI symptoms in 81% and 62% of study visits, respectively, compared to 68% and 27%, respectively, for those with only GI detection, and had longer GI shedding (17.5±6.6 v. 15.9±2.9 days).

Conclusion

Cryptosporidium was detected in both respiratory and GI tracts throughout the 8 weeks post-enrollment. The development of therapeutics for Cryptosporidium in children should target the respiratory as well as GI tract.

We conducted a prospective, observational longitudinal study of Malawian children 2–24 months hospitalized with diarrhea. NP swabs, induced sputum and stool specimens were collected. Participants that were positive by Cryptosporidium PCR in any of the three compartments were followed up with fortnightly visits up to 8 weeks post-enrollment. Cryptosporidium was detected by PCR in 21%, 7% and 3% in stool, sputum and nasopharynx of children hospitalized with diarrhea. Of those positive at enrollment, detection was noted in 44%, 20%, and 8%, respectively, by 8 weeks post-enrollment.

Disseminated Cryptosporidium infection in an infant with CD40L deficiency

The protozoan Cryptosporidium affects the digestive tract of humans and animals. Cryptosporidiosis leads to diarrhoea mimicking a cholera-like course with dehydration and may even result in death in immunodeficient patients, as patients with hyper-IgM syndrome. We describe a rare case of disseminated Cryptosporidium infection in a seven- year-old boy with CD40 L deficiency. During the pre-graft phase, the patient presented an intestinal cryptosporidiosis which became complicated few days later during the aplasia period with a cholangitis and pulmonary cryptosporidiosis. Cryptosporidium hominis was identified. After treatment with nitazoxanide and azithromycine the patient was doing well.

Competency Assessment: Diagnostic Methods for Detection of Cryptosporidium, Microsporidia, and Toxoplasma in Bronchoalveolar Lavage Samples

Background: Protozoa have the ability to replace the human lung. Over recent years, the incidence of pulmonary infections caused by these microorganisms has increased, particularly in individuals with an immunodeficiency. The use of appropriate diagnostic methods is particularly important in the identification of parasites in pulmonary secretions. Objectives: The present study aimed to evaluate and compare PCR-based diagnostic methods with the gold standard method to detect three pathogenic protozoa, including Toxoplasma, Cryptosporidium, and Microsporidia in bronchoalveolar lavage (BAL) samples obtained from immunocompromised patients with chronic obstructive pulmonary disease. Methods: A BAL sample of immunodeficient patients suffering from chronic obstructive pulmonary disease (COPD) was examined by direct microscopy and PCR methods. Results: In this study, we examined 64 patients with immunodeficiency accompanied by COPD. Microsporidia were not identified in the samples. Direct methods identified three and nine cases of Toxoplasma and Cryptosporidium, respectively. However, the molecular method identified two and two cases of pulmonary infection with these parasites. Conclusions: Determining the standard diagnostic method for parasites is dependent on factors, such as the type of specimen and the type of parasite. Based on the results of the present study, the direct microscopic method is the optimal diagnostic method for Toxoplasma and Cryptosporidium in BAL samples.

Novel allosteric covalent inhibitors of bifunctional Cryptosporidium hominis TS-DHFR from parasitic protozoa identified by virtual screening

Protozoans of the genus Cryptosporidium are the causative agent of the gastrointestinal disease, cryptosporidiosis, which can be fatal in immunocompromised individuals. Cryptosporidium hominis (C. hominis) bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) is an essential enzyme in the folate biosynthesis pathway and a molecular target for inhibitor design. Previous studies have demonstrated the importance of the ChTS-DHFR linker region "crossover helix" to the enzymatic activity and stability of the ChDHFR domain. We conducted a virtual screen of a novel non-active site pocket located at the interface of the ChDHFR domain and crossover helix. From this screen we have identified and characterized a noncompetitive inhibitor, compound 15, a substituted diphenyl thiourea. Through subsequent structure activity relationship studies, we have identified a time-dependent inhibitor lead, compound 15D17, a thiol-substituted 2-hydroxy-N-phenylbenzamide, which is selective for ChTS-DHFR, and whose effects appear to be mediated by covalent bond formation with a non-catalytic cysteine residue adjacent to the non-active site pocket.

Prevalence of Cryptosporidium spp. in calves under one year old in Ilam county (Iran), from March 2014 to February 2015

Introduction

Cryptosporidium is a coccidian parasite that can infect most mammals, including humans. This parasite is an important cause of neonatal diarrhea and morbidity in calves, causing substantial economic loss to animal husbandry. Because of the importance of this parasite in calves, this study was designed in order to determine prevalence of Cryptosporidium spp. among calves under one year old in Ilam county (Iran).

Methods

Prevalence of Cryptosporidium spp. was estimated using a cross-sectional study. Fecal samples from 400 calves under 1 year old were collected in Ilam County, from March 2014 to February 2015 and they were microscopically analyzed using modified Ziehl-Neelsen method (mZN).

Results

The overall prevalence of Cryptosporidiosis in calves was 16% (64/400). According to age categories, the highest infection was observed in calves under one month old, and the lowest infection occurred in calves 6 to 12 months old. Age was significantly associated with Cryptosporidium spp. infection (p<0.05). The prevalence of Cryptosporidiosis in diarrheic and none diarrheic calves was 27.3 and 12.4 % respectively, which indicated a significant association between positivity and diarrhea (p<0.05). The highest prevalence was observed in winter followed by autumn, spring and summer respectively. No statically difference was found between prevalence of Cryptosporidiosis and seasons of sampling. Also, calves’ gender was not associated with Cryptosporidium spp. infection in this study.

Conclusion

Our results provide useful information about the distribution of Cryptosporidium spp. Also, the role of potential risk factors including age, sex, clinical status and seasons of sampling was indicated in studied calves from Ilam County.

Disseminated cryptosporidiosis: Case report and literature review

Cryptosporidiosis, better known as an intestinal disease may disseminate to infect other sites including the respiratory tract. Little information however is available on respiratory cryptosporidiosis that may largely be due to lower frequency of respiratory cryptosporidiosis. Respiratory cryptosporidiosis has been majorly reported in immunocompromised individuals and children. Here we report a case of respiratory and intestinal cryptosporidiosis in a fifteen months old child with CD8+ deficiency. The patient in spite of treatment with Nitazoxanide and Azithromycin followed by Intravenous immunoglobulin and Bovine colostrum had a fatal outcome. The Cryptosporidium spp. isolate was subjected to molecular characterization. The Cryptosporidium spp. was identified both in stool specimen and Endotracheal aspirate (ETA). The blood sample was negative for Cryptosporidium spp. The Cryptosporidium spp. isolate from stool as well as ETA was identified as Cryptosporidium hominis (C. hominis) using Multiplex Allele Specific Polymerase Chain Reaction assay and was subtyped as IaA23G1R1 subtype using gp60 gene polymerase chain reaction assay followed by sequencing.

The evolution of respiratory Cryptosporidiosis: evidence for transmission by inhalation

The protozoan parasite Cryptosporidium infects all major vertebrate groups and causes significant diarrhea in humans, with a spectrum of diseases ranging from asymptomatic to life-threatening. Children and immunodeficient individuals are disproportionately affected, especially in developing countries, where cryptosporidiosis contributes substantially to morbidity and mortality in preschool-age children. Despite the enormous disease burden from cryptosporidiosis, no antiprotozoal agent or vaccine exists for effective treatment or prevention. Cryptosporidiosis involving the respiratory tract has been described for avian species and mammals, including immunocompromised humans. Recent evidence indicates that respiratory cryptosporidiosis may occur commonly in immunocompetent children with cryptosporidial diarrhea and unexplained cough. Findings from animal models, human case reports, and a few epidemiological studies suggest that Cryptosporidium may be transmitted via respiratory secretions, in addition to the more recognized fecal-oral route. It is postulated that transmission of Cryptosporidium oocysts may occur by inhalation of aerosolized droplets or by contact with fomites contaminated by coughing. Delineating the role of the respiratory tract in disease transmission may provide necessary evidence to establish further guidelines for prevention of cryptosporidiosis.

Cryptosporidiosis and Cryptosporidium species in animals and humans: a thirty colour rainbow?

Parasites of the genus Cryptosporidium (Apicomplexa) cause cryptosporidiosis in humans and animals worldwide. The species names used for Cryptosporidium spp. are confusing for parasitologists and even more so for non-specialists. Here, 30 named species of the genus Cryptosporidium are reviewed and proposed as valid. Molecular and experimental evidence suggests that humans and cattle are the hosts for 14 and 13 out of 30 named species, respectively. Two, four and eight named species are considered of major, moderate and minor public health significance, respectively. There are at least nine named species that are shared between humans and cattle. The aim of this review is to outline available species information together with the most commonly used genetic markers enabling the identification of named Cryptosporidium spp. Currently, 28 of 30 named species can be identified using the complete or partial ssrRNA, serving as a retrospective 'barcode'. Currently, the ssrRNA satisfies the implicit assumption that the reference databases used for comparison are sufficiently complete and applicable across the whole genus. However, due to unreliable annotation in public DNA repositories, the reference nucleotide entries and alignment of named Cryptosporidium spp. has been compiled. Despite its known limitations, ssrRNA remains the optimal marker for species identification.

Cryptosporidium parvum in diarrheic calves detected by microscopy and identified by immunochromatographic and molecular methods

Cryptosporidium is an important protozoan parasite that causes diarrhea in neonates and young bovines. The objective of the present study was to determine the frequency of Cryptosporidium infection in animals of dairy farms of the Metropolitan Region (Santiago), Chile. Fecal samples of 205 newborn calves with diarrhea were studied and used for comparing the efficiency of two microscopic staining methods for diagnosis of the parasite, the auramine (AU) and a modified Ziehl-Neelsen (ZN) procedure. Out of the 205 fecal samples, we detected oocysts in 115 (56.1%) with AU and 102 (49.8%) with ZN. Comparison of results obtained with the two microscopic techniques showed significant difference (p<0.05), AU being more sensitive. On the other hand, concordance between the two methods was almost perfect (kappa value of 0.83). The results with these two operator dependent methods were confirmed using an operator independent immunochromatographic (IC) method. The IC method also enabled us to determine the identity of the parasite species as that of Cryptosporidium parvum. Identification of the parasite species was further corroborated by performing a Cryptosporidium species-specific polymerase chain reaction (PCR) test on few samples taken at random. Overall, the results showed a high number of infected animals suggesting the parasite C. parvum as a major parasitic disease agent of neonatal calves with diarrhea in dairy farms of the Metropolitan Region (Santiago) of Chile.

Respiratory cryptosporidiosis in HIV-seronegative children in Uganda: potential for respiratory transmission

BACKGROUND

Respiratory cryptosporidiosis is recognized as a late-stage complication in persons with human immunodeficiency virus (HIV) infection and AIDS. However, respiratory signs and symptoms are common in otherwise healthy children with intestinal cryptosporidiosis, which suggests that respiratory infection may occur in immunocompetent hosts.

METHODS

We recruited children 9-36 months of age who presented with diarrhea to Mulago Hospital in Kampala, Uganda, from November 2007 through January 2009. Children with stool samples positive or negative for Cryptosporidium species were selected for further evaluation, including sputum induction in those with cough or unexplained respiratory signs and collection of saliva and blood specimens. Sputum samples were subjected to comprehensive bacteriologic testing, and both sputum and saliva specimens were tested for Cryptosporidium species by nested polymerase chain reaction.

RESULTS

Of 926 fecal samples screened, 116 (12.5%) were positive for Cryptosporidium. Seventeen (35.4%) of 48 sputum samples tested from children with positive stool samples were positive for Cryptosporidium. Sixteen (94.1%) of the 17 children with confirmed respiratory cryptosporidiosis were HIV seronegative, and 10 (58.8%) of 17 children were not malnourished. None of the 12 sputum specimens from children with negative stool samples tested positive for Cryptosporidium (P = .013, compared with children who tested positive for Cryptosporidium in the stool). Parasite DNA was detected in only 2 (1.9%) of 103 saliva samples (P < .001, compared with sputum samples).

CONCLUSIONS

Respiratory cryptosporidiosis was documented in one-third of HIV-seronegative children who were tested. These novel findings suggest the potential for respiratory transmission of cryptosporidiosis. Trial registration. ClinicalTrials.gov identifier: NCT00507871.

Analysis of the genetic diversity within Cryptosporidium hominis and Cryptosporidium parvum from imported and autochtonous cases of human cryptosporidiosis by mutation scanning

The present study investigated sequence variation in part of the 60 kilodalton glycoprotein (pgp60) gene among Cryptosporidium hominis and Cryptosporidium parvum isolates (n=115) from citizens of the UK inferred to have been infected whilst travelling abroad (to 25 countries) or in the UK. The genomic DNA samples from these isolates were subjected to PCR-coupled single-strand conformation polymorphism analysis, followed by targeted sequencing of pgp60. Individual samples were classified to the genotypic and subgenotypic levels based on phylogenetic analysis (Bayesian inference) of pgp60 data, including published sequences for comparison. Based on this analysis, five C. hominis (Ia-If) and four C. parvum (IIa, IIc-IIe) genotypes were identified, equating to 16 and 10 subgenotypes, respectively. Of these genotypes, C. hominis Ib was predominant (n=82). Interestingly, one subgenotype (C. hominis Ib A10G2R2) accounted for the majority of the samples examined and was identified in travellers to 14 countries; the examination of published records suggested that C. hominis Ib A10G2R2 has a global distribution. Numerous new and seemingly rare subgenotypes (eight for C. hominis and six for C. parvum) were also discovered. In conclusion, the present study revealed substantial genetic variation in pgp60 within both C. hominis and C. parvum and emphasizes the need to undertake investigations of human and animal populations in countries for which there is no information on the genetic make-up of Cryptosporidium infecting humans.