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.

Immune response and intestinal permeability in children with acute gastroenteritis treated with Lactobacillus rhamnosus GG: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Probiotics have a possible role in the treatment of pediatric acute gastroenteritis. We report the effect of the probiotic Lactobacillus rhamnosus GG (LGG) on intestinal function, immune response, and clinical outcomes in Indian children with cryptosporidial or rotavirus diarrhea. METHODS: Children with gastroenteritis aged 6 months to 5 years, testing positive for either rotavirus or Cryptosporidium species in stool (coinfections were excluded), were randomized to LGG (ATCC 53103) or placebo, once daily for 4 weeks. Baseline demographic and clinical details were obtained. Sera were tested for immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies to Cryptosporidium and rotavirus, and the lactulose to mannitol ratio for intestinal permeability was determined at baseline and at the end of follow-up. RESULTS: Of the 124 children enrolled, 82 and 42 had rotavirus and cryptosporidial diarrhea, respectively. Median diarrheal duration was 4 days; one-third of the children had severe diarrhea. Baseline and clinical parameters were comparable between children receiving LGG and placebo. At the end of follow-up, fewer children with rotavirus diarrhea on LGG had repeated diarrheal episodes (25% vs 46%; P = .048) and impaired intestinal function (48% vs 72%; P = .027). Significant increase in IgG levels postintervention (456 vs 2215 EU; P = .003) was observed in children with rotavirus diarrhea receiving LGG. Among children with cryptosporidial diarrhea, those receiving LGG showed significant improvement in intestinal permeability. CONCLUSIONS: LGG has a positive immunomodulatory effect and may be useful in decreasing repeated episodes of rotavirus diarrhea. Improvement in intestinal function in children with rotavirus and cryptosporidial gastroenteritis emphasizes the role of probiotics in treating intestinal impairment after infection. CLINICAL TRIALS REGISTRATION: CTRI/2010/091/000339.

Novel in vitro and in vivo models and potential new therapeutics to break the vicious cycle of Cryptosporidium infection and malnutrition.

BACKGROUND: Although several animal models of cryptosporidiosis have been reported, most involve genetically or pharmacologically immune-suppressed hosts. METHODS: We report challenge with excysted (in vitro and in vivo) and unexcysted (in vivo) Cryptosporidium parvum oocysts in human colonic adenocarcinoma (HCT-8) cells and weaned nourished and malnourished C57BL/6 mice, following outcomes of growth rate, stool shedding, and tissue burden. We tested treatment with an oligodeoxynucleotide containing unmethylated CpG motif (CpG-ODN) and alanyl-glutamine in vivo and in vitro. RESULTS: C. parvum-challenged mice showed prolonged weight loss (>10% over 4 days), robust stool shedding (>3 logs/d over 7 days), and epithelial infection in the ileum, cecum, and colon. Of 2 potential therapeutic compounds evaluated in the model, CpG-ODN reduced body weight loss (to <6% on days 3-7 after challenge), reduced shedding of organisms (by 25% on days 1 and 3 after challenge), and decreased the burden of parasites in the ileum. Alanyl-glutamine showed similar benefits. In vitro findings suggested that effects on the epithelial component of the mucosa probably likely responsible for beneficial effects seen in vivo. CONCLUSIONS: Weaned mice provide a convenient and reproducible model of cryptosporidial disease, including its vicious cycle with body weight loss and heavier infection with malnutrition, and this model may be useful in exploring innovative therapeutic solutions for this challenging infectious disease.

Indole metabolites generated by microbiota inhibit Cryptosporidium growth.

Funkhouser-Jones et al. recently identified gut metabolites that affected Cryptosporidium growth. A key focus, indole, was shown to inhibit the parasite in vivo and in vitro by decreasing the host mitochondria function and the membrane potential of parasite mitosomes. These findings help clarify the role microflora and metabolites play in host resistance.

Cholangiocarcinoma complicating secondary sclerosing cholangitis from cryptosporidiosis in an adult patient with CD40 ligand deficiency: case report and review of the literature.

A 43-year-old man with a hyper-immunoglobulin M syndrome due to CD40 ligand deficiency presented with insidious onset of recurrent diarrhoea and deranged liver function tests. Standard stool microscopy was repeatedly negative for cryptosporidia but immunofluorescent testing and polymerase chain reaction demonstrated the presence of infection eventually. Despite both paromomycin and nitazoxanide, he developed sclerosing cholangitis secondary to cryptosporidial infection. Whilst being considered for dual bone marrow and liver transplantation, he was found to have cholangiocarcinoma on imaging after three biopsies of a suspicious lesion. This is a rare complication of this combined immune deficiency predominantly in children that has not been reported previously in a long-term survivor with this condition.

Minireview: clinical cryptosporidiosis.

Cryptosporidium has emerged as an important cause of diarrhoeal illness worldwide, especially amongst young children and patients with immune deficiencies. Usually presenting as a gastro-enteritis-like syndrome, disease ranges in seriousness from mild to severe and signs and symptoms depend on the site of infection, nutritional and immune status of the host, and parasite-related factors. Sources and routes of transmission are multiple, involving both zoonotic and anthroponotic spread, and facilitated by the resistance of the parasite to many commonly used disinfectants. Prevention and control measures are important for the protection of vulnerable groups since treatment options are limited. This review covers the life cycle, pathogenesis, clinical presentations, diagnosis, prevention and management of cryptosporidiosis in humans.

[Cryptosporidiose (C. parvum) in a foal with diarrhea]. / Cryptosporidiose (C. parvum) bei einem Fohlen mit Durchfall.

The protozoon parasite Cryptosporidium parvum is an important cause of diarrhea in farm animals, but it can also infect other animals and humans. In this case report, oocysts of Cryptosporidium spp. were microscopically detected by modified Ziehl-Neelsen staining in the feces of a 9 day old Arabian colt presented with yellowish, foul smelling, diarrhea and fever of 40 degrees C. PCR and sequencing of the isolate revealed C. parvum (bovine genotype). Hemato-chemical analysis of the foals blood revealed a marked hypogammaglobulinaemia (IgG 108mg/dl). The colt responded well to a supportive therapy and administration of plasma (until a gammaglobulin-concentration of 620 mg/dl was reached) and was released in good health from the clinic after 10 days. Follow-up testing for Cryptosporidium oocycsts remained negative. Cryptosporidiosis with life-threatening diarrhea is a rare diagnosis in foals in Switzerland. Immunodeficiency increases the risk for cryptosporidiosis. We hypothesize that the low concentration of gammaglobulins together with the weak INF-gamma response normally observed in young foals may have favored the clinical manifestation with diarrhea. Foals with diarrhea should be screened for cryptosporidia with specific tests.

Oral delivery of L-arginine stimulates prostaglandin-dependent secretory diarrhea in Cryptosporidium parvum-infected neonatal piglets.

OBJECTIVES: To determine if oral supplementation with L-arginine could augment nitric oxide (NO) synthesis and promote epithelial defense in neonatal piglets infected with Cryptosporidium parvum. MATERIALS AND METHODS: Neonatal piglets were fed a liquid milk replacer and on day 3 of age infected or not with 10(8) C. parvum oocysts and the milk replacer supplemented with L-arginine or L-alanine. Milk consumption, body weight, fecal consistency, and oocyst excretion were recorded daily. On day 3 postinfection, piglets were euthanized and serum concentration of NO metabolites and histological severity of villous atrophy and epithelial infection were quantified. Sheets of ileal mucosa were mounted in Ussing chambers for measurement of barrier function (transepithelial resistance and permeability) and short-circuit current (an indirect measurement of Cl secretion in this tissue). RESULTS: C. parvum-infected piglets had large numbers of epithelial parasites, villous atrophy, decreased barrier function, severe watery diarrhea, and failure to gain weight. L-Arginine promoted synthesis of NO by infected piglets, which was unaccompanied by improvement in severity of infection but rather promoted epithelial chloride secretion and diarrhea. Epithelial secretion by infected mucosa from L-arginine-supplemented piglets was fully inhibited by the cyclooxygenase inhibitor indomethacin, indicating that prostaglandin synthesis was responsible for this effect. CONCLUSIONS: Results of these studies demonstrate that provision of additional NO substrate in the form of L-arginine incites prostaglandin-dependent secretory diarrhea and does not promote epithelial defense or barrier function of C. parvum-infected neonatal ileum.

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.

Molecular targets for detection and immunotherapy in Cryptosporidium parvum.

Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrheal illness cryptosporidiosis in humans and animals. Although C. parvum is particularly pathogenic in immunocompromised hosts, the molecular mechanisms by which C. parvum invades the host epithelial cells are not well understood. Characterization of molecular-based antigenic targets of C. parvum is required to improve the specificity of detection, viability assessments, and immunotherapy (treatment). A number of zoite surface (glyco)proteins are known to be expressed during, and believed to be involved in, invasion and infection of host epithelial cells. In the absence of protective treatments for this illness, antibodies targeted against these zoite surface (glyco)proteins offers a rational approach to therapy. Monoclonal, polyclonal and recombinant antibodies represent useful immunotherapeutic means of combating infection, especially when highly immunogenic C. parvum antigens are utilized as targets. Interruption of life cycle stages of this parasite via antibodies that target critical surface-exposed proteins can potentially decrease the severity of disease symptoms and subsequent re-infection of host tissues. In addition, development of vaccines to this parasite based on the same antigens may be a valuable means of preventing infection. This paper describes many of the zoite surface glycoproteins potentially involved in infection, as well as summarizes many of the immunotherapeutic studies completed to date. The identification and characterization of antibodies that bind to C. parvum-specific cell surface antigens of the oocyst and sporozoite will allow researchers to fully realize the potential of molecular-based immunotherapy to this parasite.

Cryptosporidium and Giardia Infections in Children: A Review.

Diarrheal disease remains the second leading cause of mortality in children in developing countries. Cryptosporidium is a leading cause and its importance stands to increase as rotavirus vaccine becomes used around the world. Cryptosporidium is particularly problematic in children younger than 2 years old and in the immunocompromised. Giardia lamblia is a common intestinal protozoan that is associated with diarrhea and, perhaps, growth faltering in impoverished settings. This review establishes the current prevalence of these infections in global settings and reviews current diagnosis and management approaches.

Prevalence of Cryptosporidium Carriage and Disease in Children With Primary Immune Deficiencies Undergoing Hematopoietic Stem Cell Transplant in Northern Europe.

A prospective cohort study of children with primary immunodeficiencies undergoing hematopoietic stem cell transplant in the United Kingdom investigated the extent and significance of Cryptosporidium carriage in this high risk group. Three of 42 children recruited were infected with Cryptosporidium, a lower proportion than previously described. One had serious disease. The underlying immunodeficiency likely had a bearing on the clinical presentation and possible outcome of infection.

Human cryptosporidiosis in Europe.

Cryptosporidium has emerged as a significant cause of diarrhoeal disease worldwide, with severe health consequences for very young, malnourished children living in endemic areas and for individuals with highly impaired T-cell functions. In Europe, as elsewhere, the burden of disease has been difficult to measure as a result of the lack of appropriate, standardized surveillance and monitoring systems. The recent occurrence of large water- and foodborne outbreaks in several EU countries, as well as the results of many surveys of human and animal cryptosporidiosis, indicate that this parasite is widespread. Specific subtypes of the zoonotic Cryptosporidium parvum and the anthroponotic C. hominis are responsible for the majority of human cases in Europe. No treatment is currently available to clear the infection, but recent progress in genetic engineering of the parasite, coupled with advances in genomics, have opened important avenues for future research. Here we explore the possible reasons for underascertainment of cryptosporidiosis and the importance of accurate diagnosis in clinical management, the epidemiology of human cryptosporidiosis and key messages from recent outbreaks to highlight important interventions and emerging public health issues.

Treating opportunistic infections among HIV-exposed and infected children: recommendations from CDC, the National Institutes of Health, and the Infectious Diseases Society of America.

In 2001, CDC, the National Institutes of Health, and the Infectious Diseases Society of America convened a working group to develop guidelines for therapy of human immunodeficiency virus (HIV)-associated opportunistic infections to serve as a companion to the Guidelines for Prevention of Opportunistic Infections Among HIV-Infected Persons. In recognition of unique considerations related to HIV infection among infants, children, and adolescents, a separate pediatric working group was established. Because HIV-infected women coinfected with opportunistic pathogens might be more likely to transmit these infections to their infants than women without HIV infection, guidelines for treating opportunistic pathogens among children should consider treatment of congentially acquired infections among both HIV-exposed but uninfected children and those with HIV infection. In addition, the natural history of opportunistic infections among HIV-infected children might differ from that among adults. Compared with opportunistic infections among HIV-infected adults, which are often caused by reactivation of pathogens acquired before HIV infection when host immunity was intact, opportunistic infections among children often reflect primary acquisition of the pathogen and, among children with perinatal HIV infection, infection acquired after HIV infection has been established and begun to compromise an already immature immune system. Laboratory diagnosis of opportunistic infections can be more difficult with children. Finally, treatment recommendations should consider differences between adults and children in terms of drug pharmacokinetics, dosing, formulations, administration, and toxicities. This report focuses on treatment of opportunistic infections that are common in HIV-exposed and infected infants, children, and adolescents in the United States.

Treatment with bovine hyperimmune colostrum of cryptosporidial diarrhea in AIDS patients.

Cryptosporidium parvum may cause severe, debilitating diarrhea in patients with AIDS. Recent anecdotal reports have suggested that hyperimmune bovine colostrum may be effective. We conducted a double-blind, controlled pilot study of hyperimmune bovine colostrum for diarrhea due to cryptosporidiosis in five AIDS patients. The patients were randomized to receive either hyperimmune or control colostrum by continuous nasogastric infusion for 10 days. All stools were collected, graded, and weighed, and the concentration of oocysts excreted was determined daily. One of the three patients treated with hyperimmune colostrum had a reduction in diarrhea and in the concentration of oocysts excreted. A second treated patient had a modest decrease in the concentration of oocysts excreted. Two patients who received control colostrum also had decreases in the volume of diarrhea but no change in the concentration of oocysts excreted. We conclude that hyperimmune colostrum with high titers of specific anti-Cryptosporidium antibody could be effective in treating patients with cryptosporidiosis. However, more studies of cow colostral immunoglobulin need to be performed so that the efficacy of this treatment can be assessed more thoroughly.

Recent advances in cryptosporidiosis: the immune response.

An increased understanding of host immune responses to Cryptosporidium parvum which are responsible for clearance of primary infection and resistance to reinfection, and characterization of the parasite molecules to which they are directed, are essential for discovery of effective active and passive immunization strategies against cryptosporidiosis. In this article, recent advances in knowledge of humoral and cellular immune responses to C. parvum, their antigen specificities, and mechanisms of protection are briefly reviewed.

Cryptosporidiosis: an update.

Cryptosporidiosis was recognised in human beings in 1976, and was prominent in the 1980s and 1990s as a cause of severe diarrhoeal illness in patients with AIDS. It is now additionally recognised as a major cause of waterborne diarrhoeal illness in developed regions, and as a pathogen with long-term effect on childhood growth and development in impoverished areas. This update focuses on recent changes in our understanding of the taxonomy of cryptosporidium, its epidemiology, effects, pathogenesis, diagnosis, and treatment.

Innate and cell-mediated immune responses to Cryptosporidium parvum.

Cryptosporidium parvum has gained much attention as a major cause of diarrhea in the world. Knowledge of the host immune mechanisms responsible for the clearance of this parasite from the gastrointestinal tract may prove to be vital for successful therapeutic treatment of cryptosporidiosis, particularly in the immunodeficient host. This chapter focuses on the innate and cell-mediated immune mechanisms associated with resistance to and resolution of a C. parvum infection. Much of the work in these areas is still in its infancy. Despite this, general consensus supports a role for interferon-gamma (IFN gamma) in mediating the initial resistance to C. parvum, although the mechanism by which this cytokine imparts resistance is unclear. It is also generally agreed that CD4+ T lymphocytes are required for the resolution of both acute and chronic cryptosporidiosis. However, the effector mechanism is again unclear. Several studies suggest that IFN gamma may also be involved in the resolution of cryptosporidiosis. However, the extent to which this cytokine is involved in the actual resolution of infection has been debated. Less extensive studies investigating the participation of other cells and cytokines in the innate and cell-mediated immune responses to C. parvum are also discussed.