Cross-sectional household transmission study of Cryptosporidium shows that C. hominis infections are a key risk factor for spread

BMC Infectious Diseases

Heather Ayres¹  Kristin Elwin¹  Rachel M. Chalmers²  Robert M. Christley³  Sarah J. O’Brien⁴  Roberto Vivancos⁵  Caoimhe McKerr⁶ 

[1] Cryptosporidium Reference Unit, Public Health Wales, Swansea, UK;Public Health Wales, Cardiff, UK;Cryptosporidium Reference Unit, Public Health Wales, Swansea, UK;Swansea Medical School, Swansea University, Swansea, UK;Public Health Wales, Cardiff, UK;NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, The University of Liverpool, Liverpool, UK;Institute of Infection and Global Health, University of Liverpool, Liverpool, UK;NIHR Health Protection Research Unit in Gastrointestinal Infections, The University of Liverpool, Liverpool, UK;NIHR Health Protection Research Unit in Gastrointestinal Infections, The University of Liverpool, Liverpool, UK;NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, The University of Liverpool, Liverpool, UK;Field Epidemiology Services, Public Health England, Liverpool, UK;NIHR Health Protection Research Unit in Gastrointestinal Infections, The University of Liverpool, Liverpool, UK;NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, The University of Liverpool, Liverpool, UK;Institute of Infection and Global Health, University of Liverpool, Liverpool, UK;Swansea Medical School, Swansea University, Swansea, UK;Public Health Wales, Cardiff, UK;

关键词: Cryptosporidium;    Protozoa;    Sporadic disease;    Household transmission;    Person-to-person;    Secondary spread;    Zoonoses;    Gastrointestinal infection;    Risk factors;    Epidemiology;   

DOI  :  10.1186/s12879-022-07086-y

来源: Springer

【 摘 要 】

BackgroundInfection with the Cryptosporidium parasite causes over 4000 cases of diagnosed illness (cryptosporidiosis) in England and Wales each year. The incidence of sporadic disease has not been sufficiently established, and how frequently this arises from contact with other infected people is not well documented. This project aimed to explore potential transmission in the home and attempt to identify asymptomatic infections, which might play a role in transmission. Risk factors and characteristics associated with spread of infection in the home were described including any differences between Cryptosporidium species.MethodsThe study identified cryptosporidiosis cases from North West England and Wales over a year and invited them and their household to take part. Each household was sent a study pack containing study information and a questionnaire, and stool sample kits to provide samples from consenting household members. Cryptosporidium-positive stool samples, identified by immunofluorescence microscopy, were characterised using molecular methods to help describe any patterns of transmission. Characteristics of households with and without additional cases were described, and compared using odds ratios (OR) and a multivariable logistic regression identified independent risk factors for household transmission. Data collection ran for one year, beginning in September 2018 with an initial pilot phase.ResultsWe enrolled 128 index cases and their households. Additional illness occurred in over a quarter of homes, each reporting an average of two additional cases. The majority of these were undiagnosed and unreported to surveillance. This burden was even greater in households where the index case was infected with C. hominis versus C. parvum, or the index case was under five years old, with mums and siblings most at risk of secondary infection. Only having an index case of C. hominis was independently associated with transmission in the multivariable model (OR 4.46; p = 0.01).ConclusionsCryptosporidium was a considerable burden in the home. At-risk homes were those where the index was less than five years old and/or infected with C. hominis. Of particular risk were female caregivers and siblings. Hygiene advice should be specifically directed here.This work provides evidence for humans as sources of C. hominis infection and that person-person is a key pathway. We recommend that all stools submitted for the investigation of gastrointestinal pathogens are tested for Cryptosporidium to better capture cases, inclusion of speciation data in routine surveillance, and the consideration of specific clinical advice on prevention for high-risk homes.

【 授权许可】

CC BY