Poor feed quality management and chicken health management in farms lead to immune deficiency of chicken. There are some toxins from fungus and various diseases such as Marek's disease, Gumboro or Infectious Bursal Disease (IBD), Lymphoid Leukosis, Avian Reovirus Infections and Chicken Infectious Anaemia found in the poor quality feed.

 

Marek's disease is one of the most common chicken epidemics universally. From 2001 to 2002, there was a serious outbreak of Marek's disease in Thailand, which caused a large number of chicken death. In 2004, many chickens were destroyed during the outbreak of bird flu. It drove chicken producers to pay more attention to farm bio-security management and various diseases did not appear in Thailand again since then.

 

In the last one to two years, Marek's disease was wide-spread in Thailand again. Marek's disease is a Herpes virus infection which led to Myelocytomatosis and death of chicken. Marek's disease is highly contagious among chicken but it will not spread to human or other mammals. Marek's disease cannot be transmitted vertically, but chicks may be exposed to the virus after hatch through infected layers. Currently, there is no effective treatment for Marek's disease and chicken will be infected by Marek's disease if exposed, in spite of vaccination.

 

 

 

Effective environmental management of farms and proper vaccination programmes are believed to be the most effective disease preventive measures for most poultry diseases.

 

For environmental management of farms, producers are recommended to improve their disease protection system and strict sterilisation of all areas in farms. Farms have to pay attention to ventilation system, feed, water supply and equipment used. Good control of feed raw materials and good feed processing system could avoid feed contamination by fungus. In order to control the spread of disease in farms, each barn should use separate tools and equipment.

 

New chicks should not be kept in barns where Marek's disease outbreak occurs. Although all chicks are vaccinated, it takes 7-28 days for chicks to build its immune system. Marek's disease can survive in room temperature for 16 weeks and new chicks may be exposed to the disease and be infected with Marek's disease.

 

Vets recommend farms to provide CVI988 strain in both single or combined vaccine with Live Attenuated Vaccine. Farms have to follow proper vaccination instruction and transfer the chicks back to farms immediately after vaccination to avoid hot weather to affect the chicks' immunity.

 

 

 

Porcine Epidemic Diarrhea virus (PED), Porcine Reproductive and Respiratory Syndrome (PRRS), Actinobacillus Pleuropneumonia (APP) and Circovirus are wide- spread in all regions of Thailand, especially in the Eastern and Western regions. The hog disease situation is more serious than that in April with more PED cases are reported.

 

PED virus in Thailand occurs from Ribonucleic Acid (RNA) virus which is composed of four main control genes, including spike protein (S), envelope protein (E), membrane glycoprotein (M) and nucleocapsid protein (N). PED virus may infect pigs of all ages, but it is most commonly found in weaned piglets. Clinical signs of infected include diarrhoea and vomitting. The intestinal wall of the dead piglet is thinner than normal pigs with milk curd in stomach.

 

Besides PED, other diseases such as PRRS, APP and Circovirus are still threatening all farms in every region of Thailand.

 

 

 

PED virus can be prevented by building proper bio-security system in farms and building immunity of piglets. Farms should be fully sterilised to remove the presence of PED virus. Feed and water supply have to be well-controlled to avoid the presence of toxin and fungus. Producers should closely monitor the health of sows by keep them away from pigs infected by PRRS, PCV2 and APP.

 

Producers can stimulate piglets' self-immunity against PED virus by giving both Live Attenuated Vaccine and Killed Vaccine. Live Attenuated Vaccine will stimulate immunity better than Killed Vaccine, while oral vaccine works better than injection vaccine. In order to build up Lactogenic Immunity, new-born piglets have to be feed by their own mother within six hours after birth.

 

In case PED is found in the farm, producers are recommended to use polyphenol, lysozyme and antimicrobial peptide to build immunity against PED virus. Prebiotic, probiotic and symbiotic should be given to the pigs to promote intestine health. When there is no sign of diarrhoea, it is recommended that farms give dehydration treatment fluid to infected pigs dissolved in water or by injection.