ABSTRACT
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.
Subject(s)
Cryptosporidiosis/epidemiology , Cryptosporidium/isolation & purification , Hematopoietic Stem Cell Transplantation , Immunologic Deficiency Syndromes/epidemiology , Child , Child, Preschool , Cryptosporidiosis/immunology , Cryptosporidiosis/parasitology , Cryptosporidiosis/therapy , Cryptosporidium/growth & development , Europe/epidemiology , Female , Humans , Immunologic Deficiency Syndromes/immunology , Immunologic Deficiency Syndromes/parasitology , Immunologic Deficiency Syndromes/therapy , Infant , Male , Prevalence , Prospective StudiesABSTRACT
A novel Cryptosporidium genotype was identified, among travellers with gastro-intestinal symptoms returning to Great Britain from the Indian subcontinent, for which we propose the name Cryptosporidium viatorum n. sp. The epidemiology of these cases was distinctly different from those with Cryptosporidium parvum and Cryptosporidium hominis. Of the 10 cases identified involving C. viatorum, most were in the first quarter of the year. One occurred in 2007, one in 2008, three in 2010 and five to end March 2011. The median age was 19 years but most were in the 20-29 years age group and seven were male. The symptoms included diarrhoea, abdominal pain, nausea, vomiting and fever. Compared with cases due to C. hominis and C. parvum, vomiting was reported less often, although the duration of gastro-intestinal symptoms was longer. The cases of C. viatorum were all travellers to the Indian subcontinent, whereas cases of C. hominis and C. parvum were more likely to have travelled elsewhere. Cryptosporidium viatorum isolates had indistinguishable sequences at each of the 70 kDa heat shock protein (HSP70), actin and ssrRNA loci which did not match any published previously and, although phylogenetically most similar to Cryptosporidium fayeri, they were distinct (<98% similarity) at the ssrRNA, HSP70 and actin genes. Morphologically, oocysts were typical of predominantly human-infecting species. Cryptosporidium viatorum n. sp. is proposed and work is warranted to investigate further the public health significance and occurrence elsewhere of this emerging parasite.
Subject(s)
Cryptosporidiosis/diagnosis , Cryptosporidiosis/parasitology , Cryptosporidium/classification , Cryptosporidium/isolation & purification , Travel , Actins/genetics , Adolescent , Adult , Age Factors , Child , Child, Preschool , Cluster Analysis , Cryptosporidiosis/epidemiology , Cryptosporidiosis/pathology , Cryptosporidium/genetics , DNA, Protozoan/chemistry , DNA, Protozoan/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Female , Gastroenteritis/diagnosis , Gastroenteritis/epidemiology , Gastroenteritis/parasitology , Gastroenteritis/pathology , HSP70 Heat-Shock Proteins/genetics , Humans , India , Infant , Male , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 18S/genetics , Seasons , Sequence Analysis, DNA , United Kingdom/epidemiology , Young AdultABSTRACT
To compare the diagnostic sensitivity and specificity of seven Cryptosporidium diagnostic assays used in the UK, results from 259 stool samples from patients with acute gastrointestinal symptoms were compared against a nominated gold standard (real-time PCR and oocyst detection). Of the 152 'true positives', 80 were Cryptosporidium hominis, 68 Cryptosporidium parvum, two Cryptosporidium felis, one Cryptosporidium ubiquitum and one Cryptosporidium meleagridis. The Cryptosporidium spp. diagnostic sensitivities of three Cryptosporidium and Giardia combination enzyme immunoassays (EIA) coupled with confirmation of positive reactions were 91.4-93.4â%, whilst the sensitivity of auramine phenol microscopy was 92.1â% and that of immunofluorescence microscopy (IFM) was 97.4â%, all with overlapping 95â% confidence intervals. However, IFM was significantly more sensitive (Pâ=â0.01, paired test of proportions). The sensitivity of modified Ziehl-Neelsen microscopy was 75.4â%, significantly lower than those for the other tests investigated, including an immunochromatographic lateral flow assay (ICLF) (84.9â%) (Pâ=â0.0016). Specificities were 100â% when the ICLF and EIA test algorithms included confirmation of positive reactions; however, four positive EIA reactions were not confirmed for either parasite. There was no significant difference in the detection of C. parvum and C. hominis by each assay, but the detection of other Cryptosporidium spp. requires further investigation, as the numbers of samples were small. EIAs may be considered for diagnostic testing, subject to local validation, and diagnostic algorithms must include confirmation of positive reactions.
