Systematic review of modifiable risk factors shows little evidential support for most current practices in Cryptosporidi
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TREATMENT AND PROPHYLAXIS - REVIEW
Systematic review of modifiable risk factors shows little evidential support for most current practices in Cryptosporidium management in bovine calves Julii Brainard 1
&
Lee Hooper 1 & Savannah McFarlane 1 & Charlotte C. Hammer 1 & Paul R. Hunter 1 & Kevin Tyler 1
Received: 13 April 2020 / Accepted: 13 September 2020 / Published online: 30 September 2020 # The Author(s) 2020
Abstract Cryptosporidiosis is common in young calves, causing diarrhoea, delayed growth, poor condition and excess mortality. No vaccine or cure exists, although symptomatic onset may be delayed with some chemoprophylactics. Other response and management strategies have focused on nutritional status, cleanliness and biosecurity. We undertook a systematic review of observational studies to identify risk or protective factors that could prevent Cryptosporidium parvum infection in calves. Included studies used multivariate analysis within cohort, cross-sectional or case-control designs, of risk factors among young calves, assessing C. parvum specifically. We tabulated data on characteristics and study quality and present narrative synthesis. Fourteen eligible studies were found; three of which were higher quality. The most consistent evidence suggested that risk of C. parvum infection increased when calves had more contact with other calves, were in larger herds or in organic production. Hard flooring reduced risk of infection and calves tended to have more cryptosporidiosis during warm and wet weather. While many other factors were not found to be associated with C. parvum infection, analyses were usually badly underpowered, due to clustering of management factors. Trials are needed to assess effects of manipulating calf contact, herd size, organic methods, hard flooring and temperature. Other factors need to be assessed in larger observational studies with improved disaggregation of potential risk factors. Keywords Calves . Cryptosporidiosis . Risk factors . Colostrum . Organic . Herd size . Flooring . Co-infection
Background Cryptosporidium parvum is a common protozoan parasite in cattle. It causes chronic diarrhoea (scour) leading to stunted growth, loss of yield and potentially death (Thomson et al. 2017; Wells and Thomson 2014). Young calves (under 6 weeks old) are at greatest risk of both catching and spreading pathogenic infection (Silverlås et al. 2009a; Wells and Thomson 2014). Economic costs in Great Britain were Section Editor: Yaoyu Feng Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00436-020-06890-2) contains supplementary material, which is available to authorized users. * Julii Brainard [email protected] 1
Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
estimated in 2014 to be £100–£200 per infected calf (Shaw 2014), arising mostly from veterinary treatment, reduced future milk yield and lower weight gain. Prevalence of C. parvum in stool samples of European cattle herds were reported to range from 13 to 100% (Imre an
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