Abstract
Background:
Cryptosporidium is a common intestine anthroponotic protozoan parasite that affects humans and other animals all over the world. Many different kinds of vertebrates have their gastrointestinal epithelium infected by the ubiquitous, obligatory parasites of Cryptosporidium spp. In humans, those with weakened immune systems, including those with AIDS, are most affected. Particularly prevalent in developing nations, cryptosporidiosis poses further difficulties for the underfunded public health system. Humans frequently harbor a number of Cryptosporidium species, whose prevalence varies according to socioeconomic level and level of animal husbandry.

Aim:
The present study was conducted to ascertain the prevalence of Cryptosporidium bovis and associated relevant risk factors of contracting cryptosporidiosis in calves and humans in Menoufia governorate, Egypt. In addition, a phylogenetic analysis was performed for additional molecular identification in order to study the evolution of the parasite and comprehend the mechanism of cryptosporidiosis evolution in the selected governorate.

Methods:
Using direct wet smear, sedimentation technique, simple faecal flotation technique, and modified Ziehl-Neelsen staining technique, parasitological analysis was conducted on faecal samples from 156 diarrhoec calves and 125 humans in Menoufia governorate PCR and phylogenetic analysis were further used.

Results:
Based on the microscopical examination, the prevalence of Cryptosporidium was 19.2% in humans and 64.1% in calves.‎ A statistical correlation was found between the prevalence of cryptosporidiosis in calves of American breeds, their early age, and the predominant warm climate. In the analyzed calves, the study was unable to detect any statistically significant difference between the type of diarrhoea and increased infection. In terms of people, the study found no significant correlation between the sex of the people under inquiry whereas a significant association was revealed among contracting cryptosporidiosis in young people, during warm climates, and among diarrhoea sufferers. PCR application produced a 4% positive result. Following phylogenetic analysis, the Cryptosporidium parvum species was identified from the PCR-positive samples.

Conclusion:
Different transmission trajectories were proposed by cluster analysis, and it was possible to put into consideration the role of calves for zoonotic transmission of cryptosporidiosis to humans.‎

Key words: Calves, Cryptosporidium, Humans, Menoufia governorate, Risk factors