Live Eimeria vaccines have been widely used in poultry for more than 50 years now and we already described the differences among each other in a previous post (Part I). Since the 80s, attempts to develop next-generation recombinant coccidiosis vaccines have led to the identification of several candidate antigens (Blake et al. 2017). In spite of this, no recombinant Eimeria vaccine has been brought to market so far. So has anything new come to market since the 1950’s?
The reality is that nothing more than classic live Eimeria vaccines has been developed since the 1950s when the first coccidiosis vaccine reached the market. At first glance, if we think about all the other vaccines that have been brought to market in the meantime – both viral and bacterial -, and given that recombinant vaccines have been available for almost a decade now, it seems that research in the field of Eimeria vaccines has failed to keep pace.
Eimeria vaccines have been widely used in poultry since the early 1950’s and their advantages have been clearly shown. In spite of this, there are some differences between them -attenuation, composition, administration route-, but they all consist of live parasites that need to undergo two and sometimes three entire life cycles inside the host gut in order to trigger the immune system and subsequently establish full protective immunity.
There are both live non-attenuated and attenuated Eimeria vaccines on the market. Live non-attenuated vaccines consist of parasites that still maintain their natural virulence. Control of the development of adverse reactions (coccidiosis disease) is achieved by using low numbers of oocysts in vaccine preparations and in some cases even by the use of anticoccidials to control the excessive spread of vaccine strains. This strategy of “controlled exposure” allows protective immunity to develop before the contamination of litter with non-attenuated oocysts becomes severe.
The importance of information and data quality in any production process is no longer a matter for debate. Poultry production is no exception to this and we are increasingly seeing how the use of technology and relevant information is on the rise. The vaccination process and, more specifically, the control of Eimeria should form part of this new information model.
In the 2016 ‘Power of Meat’ survey, one of the emerging trends was consumers’ increasing awareness regarding traceability and transparency in the production process of the meat they consume.
There is a general consensus that consumers in the future will be more sensitive towards where their meat comes from and treatments given to animals used for meat production. For example, the same survey from 2017 stated that “antibiotic-free” was the most highly valued specific characteristic for poultry meat consumers ahead of others such as “organic” or “natural”.
A vaccine dose does not depend on body weight: the mechanism of action of vaccines is different to that of antibiotics and, as a result, the dose does not depend on the body weight of the target animal. When considering vaccines against coccidiosis in poultry, the dose is made up of a suspension of sporulated oocysts of different species of Eimeria.
In this suspension, the oocysts are not evenly distributed unless it is mixed thoroughly. If, in addition to this, the dose is reduced, the chance that the chicks will receive all the oocysts of every species decreases exponentially.
A vaccine does not have to be distributed throughout the body and the vaccine components (antigen and adjuvant) do not act directly on the pathogen. In general, the activity of vaccines starts with a rapid and local innate response depending on the route of administration.
HIPRA, the reference in Animal Health and prevention, positions itself as the only company able to develop a system of vaccine administration against the main Eimeria species with its own traceability, with the development and production of its own machines and software developed internally and entirely to create traceability and services for our customers.
So Hipraspray® is the first device specially developed for the administration of the coccidia vaccines EVALON®, developed especially for long life-cycle birds, and HIPRACOX®, a vaccine developed mainly for short life-cycle birds, the formulation of which contains E. praecox, an Eimeria strain that sets it apart from its competitors.
HIPRA has overcome structural and strategic changes to develop its own vaccine administration medical devices to ensure the maximum efficacy and correct administration of its vaccines. Not only that, HIPRA’s innovation in vaccination also provides valuable information to support the decision-making process.
Market situation and acceptance of new Eimeria vaccine administration devices for poultry.
In light of the desperate need for parameter optimisation in the livestock farming industry, HIPRA has emerged as leader in the traceability of vaccination processes.
In terms of prevention against diseases caused by Eimeria in chickens, Hipraspray® represents a turning point and a major leap forward in the use of vaccination devices. With this system, HIPRA offers a high performance vaccination device specifically designed to ensure maximum efficacy of its EVALON® and HIPRACOX® products. In short, HIPRA brings some added value to both the hatchery and the final producer.
Coccidiosis – due to parasites of the genus Eimeria – is one of the most devastating diseases in poultry: a disease which has always being present in every poultry flock since the first chick appeared on the earth; in fact, Eimeria is an ever-present parasite that it is impossible to eradicate. For this reason, a coccidiosis prevention strategy needs to be put in place for each batch of chickens that arrives on a farm. Worldwide losses due to coccidiosis in poultry are estimated to be around US$1.5 billion/year.
From the 1950s the use of some chemical molecules has been implemented to prevent the effects of the several Eimeria species that cause the disease. Whereas the use of vaccines is quite commune in breeders, only between 5 and 6% of broilers in the world are actually vaccinated instead of being treated with anticoccidials.
The Eimeria species responsible for coccidiosis in the species Gallus gallus are: E. acervulina, E. maxima, E. mitis, E. praecox and E. tenella, which are responsible for the disease in short life-cycle poultry (broilers), and E. necatrix and E. brunetti, which, together with the above 5 species, are responsible for the occurrence of outbreaks in long life-cycle poultry (breeders and layers). They are all ubiquitous in their behaviour and vary in their pathogenicity.
There are seven Eimeria species that are responsible for avian coccidiosis, 5 of which cause the disease in broilers: E. acervulina, E. mitis, E. tenella, E. maxima and E. praecox.
Seven species of Eimeria (E. acervulina, E. brunetti, E. maxima, E. mitis, E. necatrix, E. praecox and E. tenella) are recognized to be causative agents of coccidiosis in chickens of the genus Gallus gallus. Until recently, Eimeria praecox was considered to be a non-pathogenic species unable to cause adverse effects in the host.
In fact, in 1970, when Johnson & Reid wrote the milestone article that for the first time standardized and described the scoring scale for lesions caused by all Eimeria spp., Eimeria praecox was not included. It was, and still is, well know that E. praecox is not able to provoke pathognomonic lesions like E. acervulina, E. brunetti, E. maxima, E. necatrix and E. tenella, however even then some researchers were investigating whether this species of Eimeria was truly non-pathogenic.