Molecular epidemiology and clinical manifestations of human cryptosporidiosis in Sweden.

This study describes the epidemiology and symptoms in 271 cryptosporidiosis patients in Stockholm County, Sweden. Species/genotypes were determined by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) of the Cryptosporidium oocyst wall protein (COWP) and 18S rRNA genes. Species were C. parvum (n=111), C. hominis (n=65), C. meleagridis (n=11), C. felis (n=2), Cryptosporidium chipmunk genotype 1 (n=2), and a recently described species, C. viatorum (n=2). Analysis of the Gp60 gene revealed five C. hominis allele families (Ia, Ib, Id, Ie, If), and four C. parvum allele families (IIa, IIc, IId, IIe). Most C. parvum cases (51%) were infected in Sweden, as opposed to C. hominis cases (26%). Clinical manifestations differed slightly by species. Diarrhoea lasted longer in C. parvum cases compared to C. hominis and C. meleagridis cases. At follow-up 25-36 months after disease onset, 15% of the patients still reported intermittent diarrhoea. In four outbreaks and 13 family clusters, a single subtype was identified, indicating a common infection source, which emphasizes the value of genotyping for epidemiological investigations.

Two geographically separated food-borne outbreaks in Sweden linked by an unusual Cryptosporidium parvum subtype, October 2010.

The number of sporadic cases of Cryptosporidium identified in the Stockholm county area increased above the expected limit during October 2010. Additionally, two food-borne outbreaks of cryptosporidiosis occurred in two other Swedish cities: Umeå (4 October) and Örebro (9 October). The outbreak investigations did not reveal any responsible food item, however fresh herbs were suspected. Thirty stool samples, originating from all three events, tested positive for Cryptosporidium oocysts. Polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) revealed that 27 individuals were infected with C. parvum, two with C. hominis, and one with C. felis. Using sequence analysis of the GP60 glycoprotein gene, a polymorphic marker with high intra-species diversity, we identified the same C. parvum subtype IIdA24G1 in samples from both the Umeå outbreak and the Stockholm area cases, thus indicating a possible outbreak in the Stockholm area and establishing a link between these two events. C. parvum IIdA24G1 has not previously been described in connection with a food-borne outbreak. For the outbreak in Örebro, another subtype was identified: C. parvum IIdA20G1e. These findings demonstrate that subtyping C. parvum isolates using GP60 gene amplification can be used to link cases in an outbreak investigation and we recommend its use in future similar events.

A food-borne outbreak of cryptosporidiosis among guests and staff at a hotel restaurant in Stockholm county, Sweden, September 2008.

In September 2008, 21 cases of cryptosporidiosis occurred among guests and staff at a wedding reception in a hotel restaurant in Stockholm county, Sweden. The most probable source of the outbreak was bearnaise sauce containing chopped fresh parsley.

Imported rocket salad partly responsible for increased incidence of hepatitis A cases in Sweden, 2000-2001.

An increased incidence of domestic hepatitis A without any obvious source of infection in Sweden and a small outbreak in late spring 2001 led to the undertaking of a case-control study. Consumption of imported rocket salad was clearly associated with disease (odds ratio 9.1, 95% confidence interval 1.5 to 69). The importation of vegetables from countries where hepatitis A is endemic to countries where this disease is not endemic continues to be a public health problem.

Molecular typing of Cryptosporidium parvum associated with a diarrhoea outbreak identifies two sources of exposure.

An outbreak of cryptosporidiosis associated with exposure to outdoor swimming-pool water affected an estimated 800-1000 individuals. PCR products were obtained from faecal specimens from 30 individuals who tested positive for Cryptosporidium oocysts. RFLP and sequencing analyses showed that all individuals were infected with Cryptosporidium parvum. Among the infected individuals, five had just swum in an adjacent indoor pool during the same period, and had no identified contact with individuals linked to the outdoor pool. With the use of subgenotyping based on analysis of three mini- and microsatellite loci, MS1, TP14, and GP15, we could identify two sources of exposure. One subtype was associated with the outdoor pool and another with the indoor pool. These data demonstrate that the use of mini- and microsatellite loci as markers for molecular fingerprinting of C. parvum isolates are valuable in the epidemiological investigation of outbreaks.