June 30, 2014
Rainy season in Thailand lowers immunity in poultry, increases bird flu, Newcastle, fowl Cholera and salmonella threats (Thailand Animal Disease Update) (Jun 2014)
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Avian diseases:
i. Coccidiosis
In summer, infectious diseases such as Coccidiosis are the most threatening diseases in the layer and broiler industry. The most common species are Eimeria Necatrix, Eimeria Tenella, Eimeria Maxima and Eimeria Acervulina. Eimeria Necatrix and Eimeria Tenella are the most serious types of Coccidiosis but they will not affect the mortality of chicken.
Two preventive measures are commonly used to prevent Coccidiosis infections, including vaccination and mixing of antibiotics in feed or water. Vaccination is preferred as infectious chicken will suffer from poor appetite. There are various medicines, such as Lonophorous (Monensin, Narasin, Salinamycin, Lasalocid, Madurmicin), Quinolones, Sulfanamides and Thiamine, which can be mixed with feed for Coccidiosis prevention.
ii. Bird Flu, New Castle and Fowl Colera
From June to September, the rainy season in Thailand increases the chances of infection of bird flu, Newcastle and fowl cholera. In June, the weather in Thailand changed from hot to tropical wet, which lowers the immunity of chicken and increases disease infections during transportation.
Although the Thai Department of Livestock Development provides vaccine for Newcastle disease and fowl cholera, the efficiency of fowl cholera vaccine is relatively low. According to Thai livestock law, vaccination for bird flu is still prohibited in Thailand.
Although Bird Flu is not found in Thailand, one man died from Bird Flu strain H5N6 in China last month. Thailand is in the negotiation process with many countries to reopen their fresh chicken market, hence it is actively monitoring bird flu outbreaks.
iii. Salmonella
Prevention of Salmonella is very important as it directly affects food safety. Salmonella protection is needed in every stage of chicken production, including at breeder farms, broiler farms and slaughterhouses. Therefore, Salmonella contamination control measures should involve coordination between farms and at every stage of production.
"Salmonella Pullorum" and "Salmonella Gallinarum" will not cause infection to human. "Salmonella Enteritidis" and "Salmonella Typimurium" will cause infection to both human and chicken. Salmonella infection in human can cause diarrhoe, fever, stomachache and dehydration. Initial clinical sign starts from fever and it may cause death in some cases of serious infection.
As the European Union is one of the main export markets of Thai cooked and fresh chicken, disease control in the Thai chicken industry is mainly based on EU regulations. EU regulations on salmonella are as follow:
  • Regulation (EC) No. 2160/2003 of the European Parliament and of the Council on the control of salmonella and other specified food-borne zoonotic agents.
  • Regulation (EC) No. 1003/2005 as regards a Community target for the reduction of the prevalence of certain salmonella serotypes in breeding flocks of Gallus.
  • Regulation (EC) No 1168/2006 as regards a Community target for the reduction of the prevalence of certain salmonella serotypes in laying hens of Gallus.  
  • Regulation (EC) No. 646/2007 as regards a Community target for the reduction of the prevalence of Salmonella enteritidis and Salmonella typhimurium in broilers.
  • Regulation (EC) No. 1177/2006 as regards requirements for the use of specific control methods in the framework of the national programmes for the control of salmonella in poultry.
Swine diseases:
PRRS remain long time problem in Thai pig industry
Recently more Porcine Epidemic Diarrhoe virus (PEDv) outbreaks are reported in Thailand. But various strains of Porcine Reproductive and Respiratory Syndrome (PRRS) remain a long-standing problem in the Thai pig industry for many years. Serious PRRS outbreak in 2010 originating from the Laos border continues to be present in every region of Thailand, particular in the western and eastern regions.
Outbreaks of Porcine Epidemic Diarrhea virus (PED), Porcine Reproductive and Respiratory Syndrome (PRRS), Antinobacillus Pleuropneumonia (APP) and Circovirus are present in all regions of Thailand. These diseases have decreased current pig production by 20%, leading to a shortage in live pig and pork in the retail market. The price of live pig increased to THB 80/kg (US$ 2.46/kg) and pork retail price increased to THB 155-160/kg (US$ 4.77-4.92/kg).
PRRS Overview
PRRS is the main disease which continues to threaten the Thai pig industry. Even though Thai pig farmers have learnt more measures in disease prevention, they are still faced with this problem.
Porcine reproductive and respiratory syndrome (PRRS) is caused by the Porcine Reproductive and Respiratory Syndrome virus. This disease causes reproductive failure in breeding stock, respiratory tract illness in young pigs and could cause immediate death of pigs. Its damage depends on their strain and infection will affect directly a pig's immunity against any other diseases. Infection in sows will bring more damage to farms as infected sows will pass the PRRS virus to their piglets.
PRRS Preventive Measure
The PRRS virus can survive in pig's blood for one month before they build immunity and it will take more than six weeks to spread the virus to other organs. Infectious PRRS virus is a chronic infection as it can stay in a pig's body for a longer time. Sero surveillance measurement for S/P ratio can help to control PRRS in farms. High S/P ratio reflects a higher chance of PRRS infection in farms while low S/P ratio means lower chances of PRRS spread.
Many pig farms seem to have difficulty in getting rid of PRRS, although the infection can be controlled. Farms should separate infected pigs from other pigs to prevent the spread of PRRS. Vaccination and good bio-security will increase efficiency in PRRS protection in pig farms.

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