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Recently in South Kalimantan a positive AI (Avian Influenza), H5N1 clade 2.3.4.4b virus was identified in commercial duck farms without vaccine programs. This virus is relatively new and different from AI viruses that have existed, AI H5N1 clade 2.3.2. clade, 2.3.2 virus was first discovered in Indonesia in 2012, where it was initially found in ducks and then also found in chickens. We need to pay attention to this, considering that the AI ​​virus easily undergoes mutations.

Facts on farms

Research on the AI ​​H5N1 clade 2.3.4 virus is still ongoing; In fact, the most common AI cases in Indonesia are H5N1 clade 2.3.2. AI cases that are seen in farms today are a decrease in production ranging from 30% to 45% and an increase in mortality for 7-10 days. Diagnosis of AI cases in farms with vaccine programs is challenging to clarify if only from clinical symptoms and surgical results because they are similar to the symptoms of other diseases such as fowl cholera and heat stress, so further examination is needed through the laboratory. However, if AI outbreaks occur on farms without a vaccine program, it will be easier to diagnose from clinical symptoms and surgical results, such as on broiler farms. Symptoms that are often encountered are bluish comb, reddish feet, inflammation of the trachea, and bleeding in various organs such as the lungs, proventriculus, ovaries, abdominal fat, and heart.

The Importance of Biosecurity Evaluation

The emergence of AI H5N1 clade 2.3.2 which is a clade that has been discovered for a long time certainly makes us all think about how this could happen even though we have tried to take precautions in such a way. Let's try to look back on what things have been done so far. Whether the action taken is appropriate or not. The main thing to pay attention to is biosecurity. The meaning of biosecurity is an effort to prevent the entry and spread of infectious diseases both inside and outside the farm. There are 3 important things related to biosecurity, farm location, cage layout and structure, and sanitation. Currently, many farms are not implementing these 3 important things, for example, the location between farms is very close, the red-yellow-green zone has not been implemented, and the implementation of poor sanitation, such as being in a hurry to sanitize the cage, no foot deeping, and disinfectant spray to guests and vehicles, as well as disinfection of cages that have not been routinely carried out.

The large number of farms with poor biosecurity can increase the chances of AI outbreaks occurring. Biosecurity itself must be carried out thoroughly, continuously, and dynamically. Sometimes there are farms whose biosecurity doesn't seem to apply, for example, wild birds that enter the cage environment which can become virus carriers and can accelerate the spread of AI. For this reason, in addition to biosecurity, it is necessary to carry out an appropriate vaccination program.

The Importance of Vaccine Programs Evaluations

Vaccination programs may be different for each farm because they must be adjusted to the conditions and history of the disease. The recommended AI vaccination program is 3x during the pullet period and 2x during the laying period. Vaccination can use Vaksimune AI plus containing H5N1 clade 2.3.2.1.c or Vaksimune AI Multi which contains subtypes H5N1 clade 2.3.2.1c and H9N2. There are still many farms that have not implemented the 3 + 2 vaccine formula. It is often found that the vaccine program is only 3x in the pullet and 1x in the laying period and there are even only 3x while in the pullet without any vaccine in the laying period. As a result, cases of AI are often found at the age of 50 weeks. Most farmers do not want to change the vaccine program because they feel that the chickens look fine. When checking antibody titers, chickens that are not re-vaccinated in the laying period tend to have low titers, and this makes chickens susceptible to AI infection because they do not have enough AI antibodies to fight AI challenges.

It is also important that the vaccine selection must have the same strain content as the strains in the field. Farmers can ask for technical service assistance in making programs, monitoring during implementation (chicken health control and taking routine antibody titers), as well as checking and analyzing problems on the farm. In addition, the technical service also monitors cases. In this case, the technical service of Vaksindo together with Agrilab and the R&D team examined samples for virus isolation, then identified them through a phylogenetic tree and carried out antigenic cartography to select vaccine master seeds. So that the vaccine can be homologous with field viruses.

Our main focus at this time is to improve and continue to update biosecurity in the farm, as well as implement an orderly vaccination program as a real effort to face the challenges of AI viruses in the future. If cases have occurred on the farm, the action that can be taken is to separate chickens that are suspected or suspected of being infected from chickens that are still healthy. In addition, it is necessary to disinfect the cage with disinfectant and revaccinate the case cage to protect healthy chickens.

by Afifah Fadlilatul, DVM