Management through the Environment

Please refer to the Life Cycle page for better understanding of this section.

To become infectious and survive, oocysts need proper temperature, relative humidity and oxygen.  Best sporulation occurs at temperatures around 29°C, relative humidity (RH) of 30-70% and with adequate access to oxygen (1-9).

Producers may reduce sporulation if any of these requirements is not met. However, because of the close relation between Eimeria and their host, changing the environment dramatically may also impact bird health.  

WARNING: The type of coccidiosis prevention program used on your farm (e.g. preventative drugs or live vaccines) can impact how you manage Eimeria through the environment. See the "Methods of Control" section for further details.

There are three main atmospheric components that can impact oocyst sporulation (1-9):

1)      Temperature

a.       Oocysts become infectious under temperatures ranging between 4 and 37°C, with an optimal temperature of about 29°C. Extreme temperatures outside of this range can kill the oocyst.

b.      As from placement (day old chicks) to two weeks of age the temperature in a typical chicken barn is maintained between 28 and 36°C, it is an ideal environment for oocysts to become infective.

2)      Relative humidity

Because barns require ventilation, the outside temperature and humidity can impact the environment of the barn. Especially if the equipment does not control the RH of the air feeding the barn. There is not a designated optimal relative humidity percentage set-out for sporulation but an RH of 35-70% is considered adequate.

 a.       Different Eimeria species may respond differently to various moisture levels, such that onset of sporulation, percentage of sporulation and viability/survivability of the sporulated oocysts could be impacted. However, faster sporulation and longer survival in the environment will increase the likelihood that an oocyst will become infective and available for ingestion to contribute to parasite transmission.  

3)      Oxygen access

a.       If the oocyst does not have adequate oxygen access during sporulation, it may not become infective. For example, the accumulation and compaction of litter can decrease oxygen access which can act to kill the oocyst. In addition, high ammonia levels resulting from accumulated litter can also kill oocysts.

Example of the minimum outside temperature needed paired with the temperature gradient needed in a generic chicken barn over the first 6 weeks of rearing to achieve an RH of 35% inside the barn (if air handling equipment does not control the RH of the air feeding the barn).    

 

Day 1-2

Day 3-4

Day 5-7

Week 2

 Week 3

 Week 4

 Week 5-6

 Relative humidity (%) inside the barn

 35

 35

 35

 35

 35

 35

 35

 Temperature (°C) inside the barn

 36

 34

 32

 29

 27

 24

 20

 Dew Point (°C) inside the barn

 18

 16

 15

 12

 10

 8

4

 

References

1. Al-Badri, R., and J.R. Barta. The kinetics of oocyst shedding and sporulation in two immunologically distinct strains of Eimeria maxima, GS and M6. Parasitology Research 111:1947-1952.2013.

2. Marquardt, W.C., C.M. Senger, and L. Seghetti. The effect of physical and chemical agents on the oocyst of Eimeria zurnii (Protozoa, Coccidia). Journal of Protozoology 7:186-189. 1960.

3. Graat, E.A., A.M. Henken, H.W. Ploeger, J.P.T.M. Noordhuizen, and M.H. Vertommen. Rate and course of sporulation of oocysts of Eimeria acervulina under different environmental conditions. Parasitol 108:497-502. 1994.

4. Waldenstedt, L., K. Elwinger, A. Lunden, P. Thebo, and A. Uggla. Sporulation of Eimeria maxima oocysts in litter with different moisture contents. Poultry science 80:1412-1415. 2001.

5. Lal, A., M.G. Baker, S. Hales, and N.P. French. Potential effects of global environmental changes on cryptosporidiosis and giardiasis transmission. Trends in parasitology 29:83-90. 2013.

6. Awais, M.M., M. Akhtar, Z. Iqbal, F. Muhammad, and M.I. Anwar. Seasonal prevalence of coccidiosis in industrial broiler chickens in Faisalabad, Punjab, Pakistan. Tropical animal health and production 44:323-328. 2012.

7. Farr, M.M., and E.E. Wehr. Survival of Eimeria acervulina, E. tenella, and E. maxima oocysts on soil under various field conditions. Annals NY Acad Sci 52:468-472. 1949.

8. Reyna, P.S., L.R. McDougald, and G.F. Mathis. Survival of coccidia in poultry litter and reservoirs of infection. Avian Diseases 27:464-473. 1983.

9. Edgar, S.A. Sporulation of oocysts at specific temperatures and notes on the prepatent period of several species of avian coccidia. Journal of Parasitology 41:214-216. 1955.