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Outbreak of Japanese Encephalitis (Pig Virus) in Malaysia

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I. Identification

1.The issue

In the early 1999, Malaysia has experienced a major disease outbreak known as Japanese Encephalitis, which was caused by the Culex mosquitoes that breed in dirty polluted water surrounding the pig farms. Some experts believed that the unsanitary conditions and poor regulation of pig farmers in managing the drainage and sewage of pig waste has caused the virus to infect the pigs population in Malaysia. Therefore,this outbreak has given the Government of Malaysian an opportunity to review the status of the pig industry and the direction for the revival of the industry ( Disease Information, 1999). This outbreak has various significant impacts on Malaysia's trade, environment and culture. Malaysia's 250 million pound of pork business suffered the most due to the sudden decline in demand for Malaysia's pork related products. For example, Singapore and Thailand have banned all imports on Malaysian livestock especially pork during the outbreak. The impact on Malaysian environment however was due to the unsanitary conditions of pig's waste that has polluted few of the Malaysian rivers. On the other hand, most of the Malaysian Chinese ethnic society has to change their diet to other meat sources. In order to control this outbreak, the Malaysian Ministry of Health has issued various protocols and prompt actions to eliminate the spread of Japanese encephalitis virus in the hope to bring the outbreak to an end. Today, the viral encephalitis outbreak in Malaysia is nearing the point where the government can soon declare that the disease has been successfully controlled. Almost everything has returned to normal with few exceptions, such as those who have lost their loved ones and some pig farmers who have been declared bankrupt. The situation in Malaysia has now returned to normal and the havoc that was once created by the Japanese Encephalitis virus has subsided. However, the government is still continuing testing other animals such as domestic dogs, cats, horses and many more as to eliminate the reservoir of the virus that can affect human.

2. Description


Japanese encephalitis is endemic in many Asian countries including Malaysia and it occurs sporadically throughout the country all year around. Since 1935, Japanese encephalitis has been in Malaysia.

Although there has been no significant increase in Japanese Encephalitis in the last few decades, the outbreaks were reported:

This outbreak in Malaysia has caused human fatalities. According to the Malaysian Ministry of Health, in 1997, the illness was reported in a number of pig-farm workers and one of them died of this disease.

In 1998, there were more reported cases of viral encephalitis. According to one government official, the disease spread within the country when the infected pigs were smuggled across state boundaries. By the end of 1998, 10 more workers had died from the disease after being in a coma for periods ranging from 4 days to a few weeks.

In the beginning of 1999, the disease had spread to Sikamat, about 60km south of Kuala Lumpur(Capital of Malaysia), through the movement of infected pigs. 7 of the workers developed the disease and 5 died in January 1999.

By March 1999, the disease had spread to the major pig farming area of Bukit Pelanduk in the state of Negeri Sembilan. As the virus spreaad, residents in this area panicked: school attendance dropped, food shops closed and pork sales plummetes. The entire of Bukit Pelandok, in Negeri Sembilan, emptied and 800 pigs were left unattened. According to the report from the Ministry of Health, it stated that for the year 1999 until the month of April, the number of confirmed JE cases reported by states are (Refer to the above map of Malaysia):

Number of JE cases
               States                               Number of cases
Negeri Sembilan35
Sarawak 11
Other states-

What is Japanese encephalitis?

Japanese encephalitis (JE), the "Plague of the Orient", is a disease caused by virus transmitted through the bite of culex mosquitoes. In Malaysia, this disease that have caused many deaths is mainly caused by a mosquito-born virus carried by infected pigs.

Where do Japanese encephalitis outbreaks occur?

Japanese encephalitis is endemic in many Asian countries. It occurs chiefly in 3 main areas:

Japanese Encephalitis also may occur with a lower frequency in Japan, Taiwan, Singapore, Hong Kong and eastern Russia.

Anually, there were 30-50,000 cases reported in Asia but the JE outbreak rarely takes place in the United States (Fact Sheet: Japanese Encephalitis, 1999).

Japanese encephalitis outbreaks do not cover large areas. Outbreaks have occured in periurban and urban population of several major Asian cities. Moreover, Japanese Encephalitis also do not last more than a couple of months. It occurs when the virus is brought into the peridosmetic environment by mosquito bridge vectors where there are pigs, which serve as amplification hosts.

Is the disease seasonal in its occurence?

The seasonality of the illness varies by country. In most regions, the period of transmission starts in April or May, and lasts until September or October. In some tropical and subtropical areas, the incidence peaks during and shortly after the rainy season, the timing depending on the region. However, where irrigation permits mosquito breeding throughout the year, transmission may occur even in the dry season. In short, whenever a particular region is temperate with seasonal rain caused by monsoon, it is the perfect place for mosquitoes to breed. For information on the risk of Japanese Encephalitis by Country, Region and Season, go to this web site.

Why Japanese encephalitis is more concentrated in Asia?

Japanese Encephalitis occurred in most of the Asian countries because these countries such as China, Malaysia, Taiwan and many more are the main exporter of pork in Asia that is still practising the traditional ways of rearing pigs.

The farmers that are still using the old ways, did not vaccinated their pigs eventhough the farms are built in areas of known JE activity. The staff that works in these farms are lacking of vaccination too. These farmers also did not invest in treatment plants to clear the effluents because the traditional ways can help them to cut down their cost which can lead to higher profitability.As a result of using the traditional ways, the rivers are clogged with pig waste because those farmers just "dump everything" into the river. The clogged river then becomes the perfect place for Culex mosquito to breed. To make the situation worse, those farmers and workers does not wear any protection gear such as mask, apron and gloves during their daily work in those pig farm, making them an easy target for the Culex mosquito. Majority of those farmers also stay near their pig farms. This also contribute to the spread of the disease.To summarize the whole scenario, the spread of this disease is because of poor management and condition of those pig farms.

By using the traditional way of pig farming, the Culex mosquitoes will have a higher possibility to breed and the virus will be easily transmitted to human.

The old methods of pig farming is the possible reason that caused the attack of Japanese encephalitis virus in Malaysia. After the spread of JE outbreak, one of the farmers in the Bukit Pelanduk village realized that the traditional ways of pig farming is not feasible anymore because it is harmful to human beings and the environment (Sittamparam and Leonard, 1999: p.7).

How is the Japanese encephalitis virus transmitted?

Japanese Encephalitis can be transmitted and spread to humans. Although the patients of JE in Malaysia were mainly Chinese, other races such as Malay and Indian are vulnerable to this disease too.

The transmission all started when the Japanese encephalitis virus multiplies in the pig's body and if the female Culex mosquito sucks the blood of the pig, she will picks up the Japanese encephalitis virus (Refer to the left picture). After an incubation period of 14 days, the Culex mosquito is able to transmit the virus to a new host, especially pigs.

Japanese encephalitis can infect humans and animals. Besides pigs as the host for the virus, other animals like cows, buffaloes, goats, sheep, dogs and cats also have shown positive reaction rates ranging from 6-66% ( Report on Japanese encephalitis,1999).

The virus cannnot be spread from human to human. Eating pork too cannot transmit the disease.

Habits of mosquitoes which carry Japanese encephalitis?

The only mosquitoes that can transmit the Japanese encephalitis virus are the Culex mosquitoes. These types of mosquito breed in dirty polluted water such as in the ponds, pools, ditches, puddles, drain and rice fields. The Culex mosquitoes are normally active between dawn and dusk that is normally from 6.30 p.m. to 6.30 a.m. Culex mosquitoes prefer pig's blood rather than human blood.

Symptoms of Japanese encephalitis ?

Japanese encephalitis begins clinically as a flu-like illness with headache, fever and often gastrointestinal symptoms. At the early stage, confusion and disturbances in behavior may occur. After 3-14 days of fever and headache, drowsiness and disorientation would take place. Later, the illness may progress to a serious infection of the brain that can lead to coma within 24-48 hours. A quarter of patients with symptoms die and the remaining one third of survivor will suffer brain damage.

Out of the reported 229 cases, most of them were men working on pig farms in Perak and Negeri Sembilan. Few other cases have been reported in abattoirs where the workers were exposed and had close contact to swine. The reason is that the virus can be transmitted when an infected pig's body fluids such as saliva, nasal discharge, blood, uterine discharge, urine and faeces, had a direct contact with human mucus. For example, a worker handling pigs sometimes feeds the pigs by hand without any protection gears such as gloves or mask. This could lead to pig's mucus secreted from its nostril to have contact with worker's hand or palm. Then, the worker does not take care of his own hygiene by eating without washing hands properly. This careless mistake mentioned above can lead to the infection of JE virus.

Other than that, the pigs too would suffered illness which occured 1-2 weeks before the illness in human. The disease in swine is not as well defined as the humans' but it appears to include rapid and labored breathing; an explosive nonproductive cough; and neurologic changes such as lethargy or aggressive behavior.

What is the possible treatment?

An effective antiviral drugs have yet to be found. The drug Ribavirin is now being given to all Japanese encephalitis patients or those suspected to have been infected with the disease to help improve their chance of recovery. According to the Health Minister of Malaysia,Datuk Chua Jui Meng, said that this treatment is given free, which costs RM 3,000 for an 11-day course of treatment per patient to save lives ( Patients given Ribavirin drug,1999:p.4 ).

What are the ways of preventing Japanese encephalitis?

Some ways of preventing the disease are:

    Eliminating all Culex breeding places

  • Providing good and proper drainage system
  • Drain or fill up all pools and puddles with sand
  • Maintain cleanliness in the piggeries
  • Conduct regular fogging exercise in and around the pig farms

    Who are those that require the vaccination against Japanese cncephalitis?

  • Workers in the pig farms
  • People staying in or near the pig farms up to a radius of 2 km, especially children

What are the ways of preventing Japanese encephalitis taken by the government?

The following actions of preventing Japanese Encephalitis have been taken by the various Ministries of Malaysia to control the outbreak of this virus ( Japanese Encephalitis and Hendra-Like Virus, 1999 ):

    Vaccination of high risk groups of the human population. According to the government, they reported that 11,276 pig farm workers were examined for signs and symptoms by active case detection, 74,647 people were vaccinated and 194,615 doses of vaccine were acquired.

    Vector control against the Culex mosquitoes by fogging and larviciding including destroying Culex breeding sites by land filling and improving sanitation/drainage. There were about 6,317 pig farms were inspected, 180,267 houses and 11,797 pig farms were fogged for the whole country untill 4 April 1999.

    Hospital management of J.E. patients.

    Health education through the mass media to inform the public on preventive measures to be taken. About 74,888 people attended the health education sessions, 200,000 pamphlets and information booklets on JE were printed and distributed by the ministry of health.

    The mass slaughter of the 1,071,631 infected pigs has been culled by the soldiers and police officers. Vaccination of 2.4 million pigs too has begin since the outbreak of J.E.( One million pigs culled during viral outbreak,1999:p.A9 ).

    Due to the isolation of the new virus additional measures must be taken by pig handlers such as wearing protective clothings, boots, gloves, gowns, goggles and face shields; and washing of hands and body parts with soap before leaving the pig farms.

    Restricting the movement of pigs from infected farms to other areas is done by the police.

    Setting up a central Control operations room to co-ordinate the activities carried out by the various ministries.

    The Malaysian authorities have banned the transport of pigs within the country. The Veterinary Services Department Director General Datuk Dr. Mohd. Nordin Mohd. Nor also said that other imports animals and horses had to be placed under quarantine before allowed into the country.

As a result of all the prevention methods that have been used by the government, the number of JE cases have dropped since December till March :

  • December - 50%
  • January - 36%
  • February - 33.3%
  • March - 9.4%

Even though the number of JE cases have reduced, the control and preventive measures by the government will still have to go on.

Below is the latest outbreak Information from The Ministry Of Health, Malaysia.

Case reported261
People Dead105
People Vaccinated 83,942
Pigs Vaccinatedstopped
Houses Fogged238,715
Farms Fogged14,167
Pigs culled1,071,631
Estimated Loss Ringgit Malaysia 4.0 Million

(Approximately US$1.05 Million)

3. Related Cases







4. Draft Author:

Kong Say Hong ( July 8,1999)

II. Legal Clusters

5. Discourse and Status:

Agreement and Completed case

6. Forum and Scope:

Malaysia and Unilateral

7. Decision Breadth:

1 country

8. Legal Standing:


III. Geographic Clusters

9. Geographic Locations

a. Geographic Domain: Asia

b. Geographic Site: East Asia

c. Geographic Impact: Malaysia

10. Sub-National Factors:


11. Type of Habitat:

Tropical Rain Forest

IV. Trade Clusters

12. Type of Measure:

Export Ban (EXBAN)

Before the viral encephalitis hit Malaysia, Malaysia is the greatest concentration of pig farms in Southeast Asia. The export ban of pork to other countries has strongly affect the pig-rearing (a $395 million industry) and other pork-related businesses. The table below shows the quantity and value (Ringgit Malaysia) of import and export of swine in Malaysia and this clearly shows that there were a huge differences in the export amount if to be compared with the year of 1998 and 1999.

The Quantity and Value of Import and Export of Swine

Quantity Value(RM)
Import of swine,1998

(Thailand,Italy,Australia,China,France,Switzerland,Vietnam,Denmark,India, U.S.)



Import of swine,1999

(Netherland,Switzerland,Thailand,Vietnam,Denmark,India,New Zealand,U.S.)



Export and re-export of swine,1998

(Brunei Darussalam, United Kingdom, Australia)



Export and re-export of swine,1999

(Brunei Darussalam)



*CIF-Cost, insurance and freight

*FOB-Free on Board

*RM 3.80 = US$1.00 (subject to fluctuation)

*Taken from MITI( Ministry of International Trade and Industry, Malaysia).

Due to the outbreak of Japanese Encephalitis in pig farms, Malaysia government will not export pork to other countries such as Singapore and Thailand. According to the Singapore Primary Product Department Director Dr. Ngiam Tong Tau, All imports of drugs, cats, horses and other livestock and mammals from Malaysia were strictly not allowed to enter Singapore. Only poultry and birds from Malaysia are allowed. The government too will impose a total ban on the import of pigs and pork from Malaysia and its neighboring countries within the next 21 months (Singapore: Only Poultry And Birds, 1999:p.3). Before the virus scare in Malaysia, Singapore usually imported 3,500 to 4,000 live pigs a day where 80% of pork came from Malaysia. As a result of high demand for pork, Singapore has started to import pork from Australia to satisfy consumers and filling a vacuum left after live pig imports from Malaysia were banned.

Other than Singapore, Thailand too has banned all imports of live pigs and pork from Malaysia. They even have set up a patrol unit on the border to detect any illegal smuggling activities.

13. Direct v. Indirect Impacts:


14. Relation of Trade Measure to Environmental Impact

a. Directly Related to Product: Yes

b. Indirectly Related to Product:Yes

c. Not Related to Product: Not Available

d. Related to Process:Yes

15. Trade Product Identification:


16. Economic Data


From the 1950's when it was a backyard industry, pig production has developed into a major component of livestock industry.

Although the production of pork has been more than sufficient to meet local demand for some years now, there is still considerable import of some 3,000-4,000 tonnes a year of processed products. This need is being addressed in recent years with some of the bigger producers bringing out locally produced bacon and ham.

Malaysia is one of the largest exporter in Southeast Asia and its pork production has been more than sufficient to meet local demand for some years now, it still compare unfavoraly to those of more agriculturally advanced countries like Taiwan. As a result, the slow improvement in bloodlines should be encouraged to boost up the production of pork.


As the population increases and becomes richer, the demand for livestock products will increase. These tables below refer to the projected demand and production respectively for livestock products,1990-2000.

Projected Demand For Livestock Products,1990-2000
Beef(tonnes) 41,00045,40054,200
Mutton(tonnes) 7,2007,6008,500
Poultry meat(tonnes) 290,000300,000416,000
Pork(tonnes) 160,000261,400288,900
Eggs(million) 4,1005,1006,100
Milk(million litres) 8201,0001,710

Projected Production For Livestock Products,1990-2000
Beef(tonnes) 14,56017,40020,200
Mutton(tonnes) 5601,0001,500
Poultry meat(tonnes) 35,640428,220539,140
Pork(tonnes) 185,000250,600290,000
Eggs(million) 4,6695,0805,980
Milk(million litres) 306080

*Source: Department Of Veterinary Services, Malaysia.

The consumption of poultry meat is expected to show the greatest increase to the year 2000 and it shows that there is much potential for further investment in the livestock industry merely to keep abreast of projected demand without unneccessary worry about marketing surplus production.

17. Impact of Trade Restriction:

High Impact


Due to the trade restriction in the pork industry, Malaysia has suffered losses of $395 million in the pig rearing and pork related businesses. For instant, Malaysia has suffered losses about RM 4.0 million due to the import banned of pork by Singapore.

Domestic Pork Sales

According to the Health Minister, Datuk Chua Jui Meng said that the domestic sales of pork have dropped drastically by 70%. He also commented that the prices of pigs were normally sold at between RM 280 and RM300 for a 80 kg pig were now going only for half that price as reported by the Federation of Livestock Farmers Association Malaysia (FLFAM) (Can pork for better sale, 1999).

This is mainly because many pork-eater have substituted the pork to chicken and vegetable. As a result, The Health Minister has suggested that Malaysia should produce more canned pork as this can revive the crippling billion Ringgit pig rearing industry.

More Demand For Chicken

The reason why demand for chicken shot up so suddenly is because the public (Chinese) are afraid that Japanese Encephalitis will be transmitted through pork. Although eating pork cannot transmit Japanese Encephalitis, the public is still concerned about the disease issue thus changing their diet to chicken.

This sudden huge demand for chicken has resulted in the increase of chicken price in the market. Prices of chicken were as high as RM6 per kilo during April and May 1999, which is the Japanese Encephalitis period compared to now, which cost RM 4.20 to 4.70.

However, this scenario remains as a short-lived joy for chicken farmers. This is because with the higher price, chicken farmers begins to import as many as RM 5 million young chicken from Thailand during the Japanese Encephalitis outbreak thus 'flooding' the market with chicken. Therefore, after the outbreak subsided, people resume eating pork thus causing the demand for chicken to fall and results in oversupply of chicken in the market. This also results in sudden drop of chicken prices causing farmers to lose about RM 0.50 per bird (Lee Yuk Peng, 1999:p.18).

Illegal Smuggling of Pigs

Due to the mass slaughter of the infected pigs, some farmers will try to smuggle their pigs to other areas or even to other countries as to help cut down their looses. There are many reports of pigs being smuggled out by land and by boat within the states in Malaysia. As a result, the authorities have set up roadblocks which under tight police surveillance to ensure farmers do not attempt to smuggle out the pigs.

18. Industry Sector:


19. Exporters and Importers:

Malaysia and many

V. Environment Clusters

20. Environmental Problem Type:


A deadly epidemic caused by Japanese Encephalitis virus in Malaysia has exposed serious flaws in the inspection, management and sanitation of pig farms and the control of infection diseases in the country.

Beyond the search to identify and control the virus, experts say it appears that unsanitary condition and poor regulation of pig farmers may have facilitated the spread of the virus (Anil Netto, 1999).

For example, the entire for example, river in mainland Penang (Malaysia) are heavily polluted with pig waste because many pig farmers did not invest in treatment plants to clear the effluents. As a result, Datuk Seri Dr. Ling Liong Sik, Deputy Chairman of Cabinet Taskforce for Japanese Encephalitis said that the authorities have decided to impose stricter enforcement on existing farms and a higher standard of cleanliness for pig-rearing activities will be introduced soon. He also insisted that the existing farms to implement cleaner and modern system or else they will have to venture into other businesses such as into vegetables, fruit farming and fish rearing (Hizreen Kamal, 1999:p.A1).

21. Name, Type, and Diversity of Species




22. Resource Impact and Effect:

Middle Impact and Scale

23. Urgency and Lifetime:-

24. Substitutes:


VI. Other Factors

25. Culture:


Ethnic Background of Malaysia

Malaysia is a multiracial country, which consists of 3 main races such as the Malays, Chinese and Indians. There is a significant contrast of culture and religion among these races. For example, the Malays (Muslims) are prohibited from consuming pork because it is regarded as unclean in Islamic thinking while the Chinese (Buddhist) consume pork as their daily diet. To make this simpler, in Malaysia, the pork meat is revered by the country's ethnic Chinese minority, but reviled by its Muslim majority. This is always a very sensitive issue among the races in Malaysia but during the outbreak of the virus, the Malaysian (all races) worked as a team to help the victims and co-operated in many activities to control the widespread of the pig virus. Although the culling operation could engender resentment among the Malaysia's Muslims, there are still majority of them involved in the operation, such as the soldiers, police officers and civil servants (mostly Muslims). From here, we can clearly see that these races have the strong bond of relationship, which can unite all Malaysian and make Malaysia a peaceful and harmony country ever in the coming millenium.

The Chinese Culture in Malaysia

In Malaysia, there are roughly about 21 million people, and out of that, 30% consist of Chinese ethnic background population.

From generation to generation, starting from China itself, pork has been part of Chinese culture in one way or the other. Pork has also been used in many important Chinese rituals and ceremonies such as Chinese New Year and "Ching Ming" (the day to worship, pray and cleaning ancestors' burial site.) The pork will be roasted and used during praying ceremonies and as offerings to the gods and ancestors.

The most interesting part is that in any Chinese ceremonies around the world, pork has been a part of Chinese rituals and cultures and to a certain extend represent their way of life. In Chinese culture, pig has many symbolic natures. They represent fertility because they can give birth to many litters at a time. Chinese also associates laziness with pigs because all pigs do is eat and sleep. Therefore, it is clear that pigs and pork plays an important role in Chinese culture and none the less comprises a key part of Chinese diet (Anil Netto,1999).

The Impact on Chinese Culture During The Outbreak

Impact on the Chinese Diet

Due to the outbreak of Japanese encephalitis, this virus had bring a big impact to most of the pork-eater in Malaysia and also Malaysia's neighboring countries. The outbreak has causes most of the Chinese to switch their diets from pork to other meat source such as chicken and fish. They exclude pork from their daily menu mainly because they are cautious of the disease and also they are becoming more health conscious, since pork are categorized as red meat.

The Chinese way of life inevitably has also been affected. The most suitable example that can be presented is "bak kut teh" (Spicy Sparerib Consomme)( Refer to right picture) a very famous dish that is savored by many fellow Chinese. This dish comprises entirely from pork meats and other pork parts. It is very delicious and some people are willing to travel great distance just to eat it. With this outbreak, this dish was supplemented with chicken since nobody want to eat pork and it affects the livelihood of "bak kut teh" seller because "bak kut teh" supposed to be made of pork, not chicken.

Surprisingly, there are still a portion of Chinese who choose to eat pork although during the JE outbreak because they have difficulties to switch their diet to chicken and vegetable. Moreover, they also believed that eating pork couldn't transmit the virus. There is a good example that I found very interesting from a newspaper cutting (Star, 22nd May 1999), stated that more than 1500 people turned up in Klang (In the state of Selangor) for a free breakfast consisted of all pork dishes such as the "Bak Kut Teh", roast pork and many more. This situation has proved that eating pork is safe and many consumers especially Chinese, were not afraid to eat pork after the Japanese encephalitis outbreak.

Impact on the Pig Farmers

Other than the pork lover, another party severely affected with this JE outbreak is the pig farmers. Most of these farmers have been involved in pig farming for generations. Due to the outbreak, many has declared bankruptcy and others has given up hope in this industry and started to venture into ostrich farming or aquaculture with the help and encouragement from Malaysian government. These forms of venture switch is similar to that of Taiwan when 40% of Taiwan's pig farmers left the industry in a similar outbreak and venture into tilapia, eels or turtles farming (Hizreen Kamal, 1999: p. A2).

Therefore, no matter what are the arguments or opinions put forward, this current JE outbreak that hit Malaysia has definitely changed the way of life of Malaysian Chinese society in one way or the other if not drastically.

26. Trans-Boundary Issues:


27. Rights:

Not Available

28. Relevant Literature

Hizreen Kamal, "Clean up or Get out", (Malaysia:Sun,July 15 1999).

"One Million pigs Culled during Viral outbreak", (Malaysia: Sun, July 15 1999).

Lee Yuk Peng, "Farmers claims Hefty Losses", (Malaysia:Star, June 29 1999).

"Steps taken to check viral Outbreak", (Malaysia: Star, May 28 1999).

Santha Oorjitham,"On Deadly Ground", (Malaysia: Asiaweek, April 2 1999).

"Patients given Ribavirin Drug", (Malaysia:Star, March 24 1999).

"Can pork for Better Sale", (Malaysia:Star, March 16 1999).

R.Sittamparam and Timothy Leonard, "Breath of fesh air and hope as lukut folk move back", (Malaysia: New Straits Times, June 5 1999).

"Malaysia agricultural Directory and index 91/92, (malaysia: Pantai Maju Sdn. Bhd.,1992).

"Import, Export and reexport of merchandise,(Malaysia: MITI, 1998-1999).

"Japanese Encephalitis and Hendra like Virus", 1999. http://dph.gov.my/press/press2/JE_HENDRA.htm

"Report on Japanese Encephalitis", 1999. http://dph.gov.my/press/press2/english.htm

Anil Netto, "Mysterious epidemic aided by poor sanitation",1999. http://www.atimes.com/food/AD

"Fact Sheet: Japanese Encephalitis", 1999. http://www.cdc.gov/ncidod/dvbid/jefacts.htm

"Disease Information", 28 May 1999. http://www.oie.int/info/AIS-71