The New Straits Times, February 1, 1999
QUESTION: There is a pig farm near my residential area. I am worried about being infected by the Japanese Encephalitis virus. I have four children, two of them under 12 years. What should I do? Is there a cure for the disease as reported recently?
A: SINCE the risk of acquiring Japanese B Encephalitis is proportional to exposure to mosquitoes that breed especially in rice-growing and pig-farming areas, it is advisable that you seek some protection for yourself and your children.
Under the present circumstances, if you are living within a 2km radius of the pig farm, then your area would be considered high-risk. This is because the carrier mosquitoes are said to be able to fly within a range of two kilometres.
One form of protection is getting vaccinated against the JE virus. The vaccine is quite effective and is usually given in three doses over a number of days. There is however no absolute guarantee of full protection. It can also be expensive with some private clinics reportedly charging between RM40 to RM80 per dose.
Generally there are no known serious side-effects associated with the vaccine. Fever and local reactions such as redness, swelling and pain are reported in fewer than 10 per cent of those vaccinated.
It is however contraindicated for pregnant women and those having liver and kidney diseases, and certain types of cancer. A new vaccine more specific for the virus involved in the present outbreak is now reportedly being developed.
Because there is no absolute protection from JE, you and your family may want to consider other types of protection. For example, cut down on the time spent outdoors especially between dusk and dawn when the infected mosquitoes normally feed. This will reduce or eliminate the chances of getting into contact with the mosquitoes.
You and your family should also use mosquito repellent or spray the surrounding area with insecticide. Repellents containing DEET (diethyltouamide) as an active ingredient are preferred.
However, some adults and children may be sensitive to chemicals which may cause allergic reactions. If this happens, wash the affected area and seek medical attention. Also be very careful especially with children since DEET-containing repellents can be toxic if ingested. Choose products which contain six to 10 per cent DEET. They can only be used on children over the age of two. Avoid the eyes and mouth.
When necessary, use mosquito netting when sleeping. Otherwise, be clothed. Always keep the environment mosquito-free.
Although the situation is now reported to be under control, it is better to be vigilant. This is because JE is endemic, making it a seasonal problem coinciding with the monsoon season in this country and elsewhere. In this country, JE can be traced way back to 1951, with a number of cases reported almost every year.
In 1992, 82 cases were reported. Statistics between 1993 and 1997 showed that the number of victims under four years were about 19 per cent, and those between five and 14 were almost 59 per cent. The number of males infected was almost double that of females. A Malaysian strain (said to be much closer to the Taiwan strain) was detected in the early 1960s, and more recently, an Ipoh strain was also detected.
Morever, there is no specific cure for the disease. Most treatments are symptomatic and supportive in nature. In this regard, one has to be very careful of any claims of an instant cure. Recently, an article in in the New Straits Times (Dec 29) reported that a "gamat" gel made from the sea cucumber could cure encephalitis, among other things.
The merit of this claim has still to be validated. It is also not clear whether this claim has withstood the stringent scrutiny of the various phases of clinical trials. It is also unclear whether health and scientific authorities have approved such claims and allowed its use as alleged.
Notwithstanding this, it is better to exercise caution and avoid getting into contact with JE-carrier mosquitoes, Culex tritaeniorhyncus.
Stay away at all costs from pig farms which serve as the breeding ground for the JE virus. Even though various animal species like wild birds, ducks, horses, cows and buffaloes could be the host, pigs seem to be more implicated at this stage. There were studies which showed that pigs had higher positive antibodies, indicating they are the preferred reservoirs for the virus in Malaysia. At times the virus may remain inactive.
Since the pig skin is relatively hairless (compared to other known hosts), it is more vulnerable to mosquito bites. Moreover pigs provide a larger surface area for mosquitoes to prey on. The pig's body temperature also allows the virus to multiply more rapidly. This is aided by the climate, especially the rainy season.
Going by on-site reports, many of the pig farms are environmentally more conducive to mosquito infestations. Most have ponds of stagnant water, often dirty and polluted, which encourage the breeding of the Culex larvae. Thus while pigs are important hosts, current farming practices contribute to the spread of the disease. It is a multi-faceted problem, suggesting there is no single step that can tackle the problem.
As such, you should insist that the relevant authorities take a serious view of your situation by dealing with the nearby pig-farming areas, especially in relation to hygiene and health. Regular fogging of the farms and their surroundings can effectively control, if not eliminate much of the mosquito breeding areas.
