ABSTRACT
AbstractPCR-based diagnostics has revealed the previously largely unknown Cryptosporidium transmission and infections in high-income countries. This study aimed to determine domestic and imported subtypes of Cryptosporidium species in Norway, evaluate their demographic distribution, and identify potential small outbreaks. Cryptosporidium-positive human faecal samples were obtained from six medical microbiology laboratories between February 2022 and January 2024, together with 22 Cryptosporidium-positive animal samples. Species and subtypes were identified by sequencing PCR products from gp60 and SSU rRNA genes. Most cryptosporidiosis cases occurred during late summer/early autumn, primarily in children and young adults. Of 550 human samples, 359 were successfully characterized molecularly (65%), revealing infection with 10 different Cryptosporidium species. C. parvum occurred in 245 (68%) human isolates with IIa and IId being major allele families, with distinct regional distribution patterns of common subtypes. A kindergarten outbreak with 5 cases was due to C. parvum IIaA14G1R1. C. mortiferum was identified in 33 (9.2%) human cases of which 24 were known to be of domestic origin, making it the second most common species in human autochthonous cases in Norway. All C. mortiferum isolates were of the same genotype; XIVaA20G2T1, including 13 cases from a suspected small outbreak in Trøndelag. C. hominis occurred in 68 typed cases (19%), but mostly in infections acquired abroad, with allele families Ib and If occurring most often. In conclusion, this study of recent Cryptosporidium spp. and subtypes in Norway, highlights the predominance of C. parvum and the emergence of C. mortiferum among autochthonous cases.
ABSTRACT
OBJECTIVE: The Norwegian Cervical Cancer Screening Programme recommends follow-up of histologically confirmed normal/cervical intraepithelial neoplasia (CIN) 1 with combined cytology and human papillomavirus testing within 6 to 12 months. This study examines adherence to guidelines and subsequent risk for CIN 3+ within this subset of women. MATERIALS AND METHODS: Women aged 25 to 69 years attending the Norwegian Cervical Cancer Screening Programme in Norway's 2 northernmost counties were included. An exposed cohort with histologically confirmed normal/CIN 1 after an atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion or atypical squamous cells - cannot exclude high-grade squamous intraepithelial lesion/high-grade squamous intraepithelial lesion enrolment cytology (n = 374) was compared with a nonexposed cohort with a normal enrolment cytology attending primary screening (N = 25,948). Risk calculations were stratified by outcomes of the first follow-up cytology. The study end point was CIN 3+ or censored at 78 months of follow-up. RESULTS: In the exposed cohort, the 42-month cumulative incidence of CIN 3+ was 9.4% (95% CI = 4.1-14.7) for women with an abnormal first follow-up cytology and 1.6% (95% CI = 0.0-3.4) for women with a normal first follow-up cytology versus 0.21% (95% CI = 0.15-0.27) in the nonexposed cohort (p < .01). The CIN 3+ risk was higher in the exposed cohort when the first follow-up cytology was abnormal (hazard ratio = 20.4, 95% CI = 11.2-37.1) compared with normal (hazard ratio = 4.7, 95% CI = 1.9-11.6) with the nonexposed cohort as reference. CONCLUSIONS: After a negative cervical biopsy, a normal first follow-up cytology provided a CIN 3+ risk considered acceptable to recommend return to routine screening in 3 years. Cytology and human papillomavirus co-testing in post-colposcopy follow-up of negative biopsies may improve risk stratification.