ANIMAL HEALTH

Zoonotic diseases significantly affect public health and also the economy. It is reported that developing countries lose 30% of the total animal production value due to animal diseases. This situation reveals the importance and urgency of a solution to eliminate animal diseases for these countries that produce with high input costs and low productivity.

Animal diseases represent threats to the environment, animal welfare, public health and the economy. Animal diseases contribute to losses through increased mortality, decreased productivity, control costs, loss of trade, decreased market value and food insecurity. The economic and social impacts of livestock diseases have been recognized globally in both developed and developing countries. Measuring the economic impact of an animal disease outbreak is important in supporting prevention and control decisions to improve animal health.

The economic costs of animal diseases can be categorized as direct or indirect losses.

This highlights that indirect costs are an important aspect of the economic impact of an animal disease epidemic and may be greater than direct costs, as these estimates suggest. While the direct costs of disease are significant, the indirect costs are also worrying because the costs of disease will not stop at the farm gate, in the agricultural sector, or after being declared disease-free. The disease can affect a wide variety of sectors of the economy, including rural trade and tourism.

A country’s animal disease status changes over time. Therefore, we assume that direct costs are the sum of the losses from the initial confirmation of a notifiable disease outbreak to the declaration of being disease-free. Accordingly, indirect costs are defined as economic losses in the affected goods markets (e.g. domestic and foreign trade) and other sectors (e.g. tourism).

Public health may be seriously threatened due to zoonotic diseases transmitted to humans from animals and animal products. It is not possible to protect human health and ensure food security in an environment where animal health cannot be guaranteed.

• High mortality rate, especially among young animals,
• Economic losses arising from restrictions on foreign trade,
• Cost in treatment costs. There is a 15% loss of milk annually due to foot and mouth disease. The financial damage stemming from the loss of milk is approximately 8 million US dollars. Loss of meat is around 10%.

The financial damage stemming from the loss of meat is 81 million US dollars. Trade in livestock and animal products may be stopped in areas where the disease appears, and imports of many agricultural products may be restricted by other countries. In Europe and in countries that have eradicated the disease, a systematic intensive vaccination program was implemented every year.

An appropriate vaccination method requires the administration of the right antigen at the right dose, at the right time and in the right way to build up optimum immunity. It is more important to prevent certain diseases, which may endanger the life of the living or cause permanent damage, before they occur, than to treat these diseases after they occur. Vaccines developed against many viral or bacterial diseases have been used in preventive medicine for a very long time. Therefore, vaccines are very important to protect animal health and prevent problems caused by zoonotic diseases.

Adjuvants are components in vaccines that help to elicit a stronger immune response and prolong vaccine protection. In other words, adjuvants help vaccines to be more effective. Some vaccines made from weakened or killed microbes contain naturally occurring adjuvants and help the body elicit a strong protective immune response. Adjuvants help the body build an immune response strong enough to protect the person from the disease for which they are vaccinated.

Adjuvants, etymologically derived from the Latin word “adjuvare” meaning “helpful” or “enhancing”, are designed to develop vaccines that have low immunogenic properties.

Adjuvants alone are not immunogenic agents.

They are substances that enable the vaccine to elicit a stronger immune response and strengthen its effect when it is added to the vaccine.

In general, adjuvants work by;

Maintaining the Th1/Th2 (helper T cell CD8+/CD4+) balance by increasing the stimulation and efficiency of the cells in the immune system, and thus reducing the amount of antigen needed for the expected immunity (antigen-vaccine dose). Moreover, they;

To date, a large number of compounds of organic, inorganic, synthetic and natural origin have shown the ability to stimulate immune responses and potent adjuvant properties. These substances can be divided into two different groups in general:

1. Distribution agents (emulsions, microparticles, mineral salts)
2. Immunostimulants [saponins, Toll-like receptor (TLR) agonists, cytokines]

Immunostimulants stimulate antigen presenting cells (APCs) and promote the secretion of various cytokines. On the other hand, it helps maintain the conformation of antigens (Ag) for proper presentation to APCs and provides a slow release for continued immune stimulation. For example, TLR agonists and other immunostimulating agents can increase immune cell recruitment and cytokine secretion, while emulsions and mineral salts can create a storage effect at the injection area with prolonged release of antigen and sustained stimulation of immune cells.
Vaccine development for food animals is different from human and companion animals. The health and well-being of the individual is of paramount importance for humans, while disease control measures need to be cost-effective for livestock.