Controlling coccidiosis is a major challenge to the poultry industry, but innovative management strategies could help prevent the disease in broilers.
Coccidiosis
Coccidiosis is caused by protozoan parasites belonging to the Eimeria genus. Infection occurs when birds ingest litter, soil, feed or water containing sporulated Eimeria oocysts. As the parasite goes through its normal lifecycle in the bird, it infects cells in the intestinal tract.
Without intervention, the parasite can multiply uninhibited and cause loose droppings, poor nutrient absorption, reduced performance and sometimes death. During the Eimeria replication, birds can become more prone to develop necrotic enteritis caused by Clostridium perfringens.
“Coccidiosis is ranked as the number one concern for broiler production,” Dr. Matilde Alfonso, a technical services veterinarian at Ceva Animal Health, said. "It costs the industry millions of dollars every year and it is not something that can be eradicated so you must control it."
There are a variety of treatment and prevention approaches, including coccidia vaccines, ionophores and chemical anticoccidials. In addition, litter management and stocking density are also critical.
Anticoccidial drugs have been used for more than 50 years. The poultry industry faced challenges with this control method due to the development of resistance and drug residues in the carcass.
The industry’s move to reduce or eliminate the use of antibiotics led to the prohibition of the usage of anticoccidial ionophores in birds classified as no antibiotics ever (NAE). Anticoccidial ionophores are classified as antibiotics in North America, so they cannot be used.
Vaccination against coccidiosis gained popularity with broiler producers in the last decade. This strategy emerged as a sustainable, safe and efficacious solution for two key industry needs. Vaccination simultaneously combats the development of resistance and meets the increased need for birds raised without antibiotics.
Coccidiosis vaccination
Coccidiosis vaccines expose birds to drug-sensitive strains of live coccidia and are administered by water-based spray or gel spray in the hatchery. This timing gives birds a uniform, controlled dose of the necessary Eimeria species, early in life. This happens before the bird gets an uncontrolled variable exposure in the poultry house.
Finding the right combination of mitigation tools takes time but leads to long-term success in staying ahead of the disease. Uniform application of a consistent vaccine is the key to a successful vaccination program. If producers start and stop vaccination, they can eventually end up chasing the disease leading to economic loss and associated animal welfare issues.
“All coccidiosis vaccines contain sporulated oocysts, but the number of oocysts that is in the vaccine can differ from vaccine to vaccine,” Dr. Roberto Soares, Ceva Animal Health's Immucox range manager, said. “This plays a significant role in the field as the vaccine cycles and the number of oocysts increases exponentially.
"Since coccidiosis vaccines contains live oocysts, the longer the vaccine is in storage before application, the more energy is consumed, and less energy is available for Eimeria to infect the cells and stimulate robust immunity."
Routine checks on storage conditions and expiration dates of vaccines are critical. Additional considerations for monitoring coccidiosis vaccination programs include assessing how the vaccine is prepared and applied, as well as measuring the effectiveness of the treatment on flock health. This should be followed by regular monitoring on the farm of how the vaccine is cycling in the flock.
Probiotics
In NAE production environments, coccidiosis control requires extra considerations.
“We definitely have more limited options” when it comes to NAE, Dr. Francene Van Sambeek, a technical consultant with Elanco Animal Health said.
“We need to make sure that the growers are really attuned to their bird health because they’re the ones that are there every day," she said. "If a problem arises, it needs to be addressed quickly because if something happens, we’ll have to go in and treat with antibiotics.”
Although vaccines are commonly used in NAE houses for coccidiosis control, probiotics are another emerging preventative. In recent years, research revealed the crucial role of poultry gut health in maintaining immunity against disease. Probiotics contain good bacteria to help support and improve intestinal integrity in the bird.
This is important because coccidia is one of the most common causes of intestinal wall damage in poultry.
“By maintaining a really high level of intestinal integrity, we can hopefully ensure optimal functionality in the gut,” Van Sambeek said.
Conveyer belt vaccination
One recent advancement in coccidiosis control is a platform technology that can individually vaccinate up to 100,000 chicks per hour against coccidiosis, infectious bronchitis and Newcastle disease.
“Fundamentally, it’s a marriage of high-speed imaging with artificial intelligence (AI),” Ramin Karimpour, CEO, TARGAN Inc., said. “It can look and recognize the features of the chick, particularly the eyes and nasal passage, at a high speed as they go through the system on a conveyer belt.
The precision technology uses a conveyer belt system to humanely deliver so-called microdoses of vaccines to day-old chicks.
This technology, which was highlighted at the 2020 Virtual Poultry Tech Summit, is currently in the commercial beta testing phase. The first commercial units were recently installed for validation in the field.
Future solutions
There are several other innovations currently in development that could transform modern coccidiosis control in poultry.
Predictive diagnostics can analyze current disease outbreak patterns to draw conclusions about the future. This gives poultry producers the ability to make preemptive changes and avoid future catastrophes, such as drug resistance.
“There’s a lot of challenges in this because coccidiosis is a wily pathogen," Dr. Jon Schaeffer, senior director of poultry technical services for Zoetis, said. "You sample litter at a chicken house, but there’s a lot of uncertainty of whether you’ve got a representative sample.”
Future technologies could tackle Eimeria’s ability to develop drug resistance. For example, researchers recently discovered a mutation in a single gene helped malaria, the human analog to coccidiosis, develop resistance to the drug Chloroquine. If that were also true in coccidiosis, a PCR probe might be able to detect resistance instantaneously, Schaeffer said.
Finally, a new platform technology uses oocysts per gram (OPG) patterns to monitor the effectiveness of coccidiosis control programs. Poultry veterinarians can use this information to make program adjustments three to four weeks earlier than could have been accomplished by waiting for flock performance results.
