One key opportunity to better control cryptosporidiosis lies in the proper use of environmental cryptosporicidal agents to prevent calves from becoming infected within the facilities.
Current data from successive samplings indicate that calves aged 3 to 21 days are universally exposed to the pathogen, regardless of whether they show clinical symptoms. The Cryptosporidium oocysts excreted in faeces remain viable under conditions of cold, humidity, and direct sunlight across various substrates. Simply removing faeces is insufficient to prevent newborns from being exposed to the pathogen. Therefore, products that are effective in different levels of solar radiation are essential. Even in cows around the peripartum period without clinical signs, the pathogen load can reach 2.4 x 109 oocysts per 100 grams of faeces, highlighting the significant contamination risk.
The study performed by Vaszques Flores et al. (2024) compared the following disinfectants:
- A commercial control
- Hydrogen peroxide 35% at two doses
- Prophyl® S (chlorocresol 17.0% and glycolic acid 4.9%) at two doses
All disinfectant treatments were tested in field conditions using common bedding types and subjected to sun, sun and shade, and shade, with a predetermined number of oocysts.
The objective was to determine the quantification and viability of Cryptosporidium spp. oocysts after treatment compared to the control groups.
Materials and method
Fifteen areas of controlled contamination were placed on substrates combined with sand, seeding the area with a controlled number of oocysts (3.3 x 105; Figure 1).
- Five in site A: front of the corral with direct sunlight
- Five in site B: inside the hutch with some exposure to sunlight
- Five in site C: inside the hutch without any exposure to sunlight
Each site (A, B and C) was treated with the disinfectant under the contact conditions indicated on the label. Laboratory and culture tests were performed to identify the level of efficiency of the product:
- Hydrogen peroxide 35% 1:50 dilution - 2 hours treatment
- Hydrogen peroxide 35% 1:100 dilution - 2 hours treatment
- Prophyl® S 2% 1:50 dilution with treatment for 6 hours
- Prophyl® S 2% 1:100 dilution with treatment for 6 hours
- Water as a control for 6 hours
Results
Table 1 shows the number of destroyed oocysts per treatment group and site.
The greatest damage to oocysts was observed with the 1:50 Prophyl® S group, due to the number of oocysts destroyed, in general counts and linear regressions in direct sunlight. This same disinfectant showed greater resistance to the sun with the highest number of whole oocysts, and oocysts that did not hatch.
The Prophyl® S 1:100 treatment presented the highest number of non-viable oocysts in the half-shade block, and in the sun and shade.
Conclusion
In all conditions, Prophyl® S outperformed hydrogen peroxide, even at a lower dilution. Prophyl® S is therefore the best choice to deactivate and destroy Cryptosporidium oocysts in field conditions both under direct sunlight and in the shade.
