Molecular Investigation and Risk Assessment of Neonatal Calf Diarrhea in Morocco: Emphasis on Rotavirus and Coronavirus Infections

Choukri, Imane and Touil, Nadia and Zouagui, Zaid and Rhazzar, Zineb and El Ouadi, Hanan and Belouad, El Mehdi and Fassi Fihri, Ouafaa and El Berbri, Ikhlass (2026) Molecular Investigation and Risk Assessment of Neonatal Calf Diarrhea in Morocco: Emphasis on Rotavirus and Coronavirus Infections. World's Veterinary Journal. 436 - 448. ISSN 23224568

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Abstract

Neonatal calf diarrhea represents a major health and economic burden in Moroccan cattle farming and remains a leading cause of calf mortality. It is commonly associated with infectious agents such as rotavirus, bovine coronavirus, Escherichia coli, and Cryptosporidium parvum, and is often aggravated by dehydration and electrolyte imbalances. The present study aimed to update the epidemiological profile of viral pathogens involved in neonatal calf diarrhea in Morocco, with particular emphasis on rotavirus group A (RVA) and bovine coronavirus (BCoV). A total of 889 newborn calves from 20 farms located in five Moroccan regions (Casablanca-Settat, Rabat-Salé-Kenitra, Souss-Massa, Fes-Meknes, and Beni Mellal-Khenifra) were included in this cross-sectional observational study. Among them, 130 rectal swabs were collected from diarrheic calves between November 2022 and March 2023 and analyzed using reverse transcription quantitative PCR (RT-qPCR). The results indicated that 34 of diarrheic calves tested positive for RVA and 62 for BCoV, with a co-infection rate of 24. Infection rates were influenced by several factors, including calf age, geographic region, dam vaccination status, calving rank, production system, and farm size. RVA infection peaked in calves aged 8�14 days, whereas BCoV was most prevalent in calves aged 21�29 days. Notably, RVA positivity was higher in calves born to vaccinated dams (40) compared to those from unvaccinated dams (20), while BCoV infection was more frequently detected in calves from heifers than from multiparous cows. Higher infection rates in calves were also observed in intensive farming systems. Overall, these findings confirmed the major role of rotavirus and bovine coronavirus in neonatal calf diarrhea in Morocco and suggest that the limited effectiveness of vaccination may be influenced by herd management, colostrum transfer, and biosecurity practices. The potential mismatch between vaccine and circulating strains highlights the need for continuous molecular surveillance. © The Author(s) 2026 Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

Item Type:	Article
Keywords:	Bovine coronavirus; Calf; Neonatal diarrhea; Risk factor; Rotavirus A
Subjects:	S Agriculture > SF Animal culture
Divisions:	World's Veterinary Journal (WVJ)
Page Range:	436 - 448
Journal or Publication Title:	World's Veterinary Journal
Journal Index:	Scopus
Volume:	16
Number:	2
Publisher:	Scienceline Publication
Identification Number:	https://doi.org/10.54203/scil.2026.wvj41
ISSN:	23224568
Depositing User:	Dr. Alireza Sadeghi
URI:	https://eprints.science-line.com/id/eprint/1712

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