Interview: Why is Eimeria Prevention Important in Your Flock?

Eimeria is a genus of parasites that infect chickens and cause coccidiosis, an extremely important disease affecting profitability for poultry producers.
calendar icon 2 August 2016
clock icon 6 minute read

The Poultry Site’s Editor Alice Mitchell spoke to Martina Dardi, Corporate Group Product Manager for Poultry at animal health company HIPRA, about this problem in the wake of the launch of the company’s new website dedicated to Eimeria prevention.

What are Eimeria and why are these species important?

Most commonly recognised coccidia parasites that infect chickens are of the genus Eimeria and all are placed within the phylum Apicomplexa. The Eimeria species that infect chickens do not infect other animals, nor do those of other animals infect chickens.

Click here to visit HIPRA’s new website dedicated to Eimeria prevention.

Coccidiosis is a disease which has always been present in every poultry flock since the first chick appeared on the earth; in fact, Eimeria is an ever-present parasite impossible to eradicate. For this reason, farms must plan preventive measures to protect chickens from coccidiosis for every single flock.

Worldwide losses due to coccidiosis in poultry are estimated to be around US$1.5 billion per year, based on direct production losses and indirect costs through the application of control measures.

How does the parasite infect birds?

This parasite has a direct life cycle, which does not involve intermediate hosts. It spreads from bird to bird and from flock to flock thanks to the ability of its oocysts to survive in the litter or soil, where they may be eaten by another susceptible chicken.

How do the different species of Eimeria differ?

All of the coccidia are pathogenic, although some, like Eimeria praecox and E. mitis, to a lesser degree. The life cycle of each Eimeria species has a different duration inside the host and as a consequence a different prepatent period. This represents a valuable diagnostic tool in identifying the species of Eimeria, together with the location and appearance of lesions, which are very specific to each different species.

How does coccidiosis impact on bird performance?

Coccidiosis causes death and in less severe cases causes intermittent diarrhoea, poor growth rates, poor feed conversion and variation in body weight.

However, we have to make a distinction: for the broiler industry, it is subclinical coccidiosis that has more impact, by undermining the efficiency of feed digestion. In contrast, the biggest concern in the breeder industry is clinical coccidiosis, which causes the death of the bird and promotes opportunistic pathologies associated with intestinal damage or birds’ stress.

The most commonly recognised species in broiler chickens are Eimeria acervulina, E. tenella and E. maxima. Eimeria praecox and Eimeria mitis are common but are recognised as responsible for subclinical coccidiosis.

In layer and breeder pullets, apart from Eimeria acervulina, E. tenella and E. maxima, we also have to consider E. necatrix and E. brunetti, which impact late in the production cycle but produce severe damage to the gut and mortality.

How can poultry farmers reduce the impact of Eimeria?

In broilers, the most commonly used prevention method by far is the inclusion of in-feed anticoccidials. These products have many merits, but the two main issues associated with their use are (i) reduced sensitivity of Eimeria parasites when a certain product is used too long or too often and (ii) cross resistance between certain compounds.

Therefore, there is an intensified need for alternative coccidiosis prevention approaches. One approach that is increasingly popular is the regular use of coccidiosis vaccines in rotation with anticoccidials as part of a long term prevention strategy. Nowadays the current regulations are focussed on prevention rather than the use of antibiotics. Coccidiosis vaccination can help to achieve these objectives.

When it comes to breeders, the situation is completely different; in fact, almost all the breeders use coccidiosis vaccines as the only prevention method. In this category of animals, which live much longer compared to a broiler, the use of anticoccidials would result in an expensive and in most cases inefficient prevention method.

What are the benefits of HIPRA’s vaccine, EVALON®, in fighting Eimeria, and how does it work?

EVALON® is a live attenuated vaccine and its composition has been formulated to protect breeders and laying hens from coccidiosis. The vaccine is a suspension of sporulated oocysts that start replication in the chicks’ guts soon after ingestion.

EVALON® is administered at one day of age via coarse spray, so the onset of immunity is achieved starting from 21 days of age. In this way, birds are already immunised when the coccidiosis field challenge usually occurs, which is starting from 28 days of age.

Moreover, EVALON® is the only coccidiosis vaccine worldwide with a demonstrated duration of immunity up to 60 weeks after vaccination. This has been achieved thanks to the adjuvant that is contained in the vaccine solvent HIPRAMUNE®T. The adjuvant boosts the cellular immune response by activating the production of Interferon-γ and IL-2, which are fundamental for protection against coccidiosis.

We truly believe that good vaccination is crucial in order to obtain a correct and timely onset of immunity. For this reason, HIPRA has decided to develop a dedicated spray device for EVALON®. This includes Hipraspray®, a special vaccination device for the hatchery with specific precision mechanisms that improve coarse spray application, and HIPRAlink®, a system that traces the entire process from the preparation of the vaccine in the hatchery to the arrival of the chicks on the rearing farm. Hipraspray® is the first spray machine on the market which is able to give traceability to the entire vaccination process.

What other products does HIPRA provide to help poultry farmers combat Eimeria?

HIPRA also has another live attenuated vaccine against coccidiosis in its portfolio - HIPRACOX®, which is intended for broilers. HIPRACOX®, in the same way as EVALON®, comes with a dedicated colouring agent and a vanillin aroma, thus enhancing intake of the vaccine even under low light conditions.

Moreover, it is the first attenuated coccidiosis vaccine for broilers which contains Eimeria praecox, a controversial species often considered as irrelevant, but that in recent studies has been demonstrated to be a possible cause of subclinical coccidiosis and consequent losses in rate of weight gain.

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