The Star, May 28, 1999

Steps Taken to Check
Viral Outbreak

by Datuk Dr Abdul Aziz Mahmood,
Deputy Director General of Health, Health Ministry

I refer to the articles entitled "Killer Unmasked" and " Doubtful Diagnosis" which appeared in the Star of May 24th.

The articles seemed to cast doubts on the ability of the Ministry of Health to diagnose and control the disease outbreak.

They also seem to cast doubts on the ability of the laboratories and our learned virologists both within and outside the Ministry of Health, including those of other countries.

Allow me to try to explain the activities that have been done to contain the outbreak.

We were very certain that the advice we received from the experts, both from Malaysia and overseas who were working closely with us from the beginning, was correct.

You were right in saying that when farmers and farm workers in lpoh started dying last year, Japanese Encephalitis (JE) was suspected. in fact even before the first death was notified to the Ministry of Health on Nov 4 last year, we had already set up a task force in June to investigate sporadic cases of viral encephalitis reported among pig farmers earlier in the year.

This task force comprised highly qualified and experienced people such as physicians, veterinary surgeons, public health officers and scientists.

They met in June and thoroughly reviewed all cases of viral encephalitis that had occurred in lpoh.

They studied the clinical signs and symptoms, the epidemiology, the laboratory findings, past history, occupation, nature of work, contacts with animals etc.

By October, all suspected cases of viral encephalitis had been individually assessed and a diagnosis of JE was made.

It was based on the following:

  • JE had been endemic in Malaysia,
  • PRESENCE of Culex mosquitoes as the vector on the pig farms,
  • THERE were Malay family members who also came down with the illness,
  • PRESENCE of the pigs as amplifying host,
  • PATIENTS had signs and symptoms of fever, deterioration of mental alertness which was suggestive of encephalitis, and
  • POSITIVE serological tests for JE from blood and cerebrospinal fluids (CSF).

During the Perak outbreak, samples from cases there were sent to the Institute of Medical Research (IMR) Virology Unit (an accredited WHO collaborating laboratory for Virology).

Virologists from IMR reported that antibodies for Japanese Encephalitis were present in 11 out of 26 cases (42%).

Hence the diagnosis of JE was confirmed.

IMR also looked into the possibility of other diseases such as Dengue, Enterovirus, Rickettsia, Leptospirosis, etc.

Their report stated that no other diseases were detected.

The Ministry is aware that the antibody level in the specimens could be due to previous vaccinations or previous subclinical infections.

We were advised by our physicians that the level of antibodies from previous vaccination would not have been detected because it would be too low for the present method of detection.

Secondly they detected IgM, indicating that they were recent infections.

The IMR sent four of the confirmed samples to the WHO collaborating centre for Tropical Diseases at Nagasaki University in Japan.

They confirmed the diagnosis made by IMR to be JE.

With the above findings, the Ministry of Health had no reasons to doubt that it was JE infections that we were dealing with.

We had consulted all our physicians and health experts from the Ministry of Health, the Veterinary Department, the IMR and the WHO collaborating laboratory in Japan.

From the evidence before us at that particular time, we announced the outbreak and started massive fogging of pig farms and surrounding areas, vaccinated all farmers on and around the farms, including those living in high risk areas (2km radius from pig farms), ran a massive health education campaign, and set up operations rooms at Federal, State and District levels.

Our Health Officers worked around the clock to ensure the outbreak was quickly controlled.

It would be negligence on our part not to institute such measures in the face of the evidence we had at that particular time.

In fact the outbreak of viral encephalitis was brought under control on Feb 20 this year when the last case was admitted to a hospital in lpoh.

All the control activities in Perak were for the control of JE. We cleaned up the breeding places and killed all the adult mosquitoes, educated people on how to protect themselves from mosquito bites, and increased their resistance to JE infection.

We successfully controlled the outbreak in 72 days.

At that time we knew nothing of the new virus and we did not even talk about personal hygiene, wearing of masks and protective gowns while handling pigs.

Neither did we get any wise advice from experts elsewhere at that time.

I agree with the statement quoting Dr Henry Too as saying that: "For a disease that causes neurological disorders affecting people who are associated with pigs, JE was a logical presumptive diagnosis during the early days of the outbreak, based on the fact that it was the only documented disease that affects the brain of those who work. with pigs."

Also that of Prof Mary Jane Cordosa that "JE normally occurs in the months of November to January. An increase in JE cases during this period is therefore nothing new nor particularly unusual."

Hence we took actions to control JE because all the evidence available before us at that particular time showed that we were dealing with JE outbreak. Then came the episode in Sikamat, Negri Sembilan.

On Dec 26 last year the first suspected case of viral encephalitis was reported by Hospital Seremban.

There were seven cases with five deaths, three of which were confirmed as JE.

From investigations done by our Health officers, we knew that pigs from Perak had been transported to the Sikamat farms.

Looking at the clinical signs and symptoms, its epidemiology, history of people movement prior to illness, the only logical conclusion was that JE had spread from Perak to Sikamat.

Our suspicions were strengthened when a Malay male living near the pig farm, aged 50 year who went fishing about 10 days prior to onset, came down with the illness and subsequently died.

From his history given by the family, he absolutely had no previous contact with pigs or the farms or even the lorry which transported the pigs from Perak.

Our health officers found Culex mosquitoes breeding in and around the Sikamat farms.

As in Perak, we instituted all the actions to control JE and the whole episode ended within nine days.

There were again no advice given by any concerned party regarding the possibility of a new infectious agent. As to the question why very few of the cases were positive for JE, and whether we made the right diagnosis, we were well aware that we cannot get 100% of patients with signs and symptoms of JE and history of contact with mosquitoes, positive for JE serologically.

Experts in medicines and virologists told us that certain cases will be negative serologically depending on when the blood is taken from the patients. However our diagnosis of JE was also confirmed by the Head of the Virology Department of Universiti Malaya, as per the letter he wrote to the Director-General of Health dated April 1 this year signed by Prof Lam Sai Kit.

I quote para three of the said letter: "A panel of serum samples from the Seremban outbreak was subjected to Quality Assurance Programme, conducted by Ms Jody Mitchell of PanBio Pty Ltd, Brisbane, and by Dr Jane Cardosa and Dr Tio Phaik Hooi of Unimas.

The preliminary results showed that the concordance were between 80% and 90%, thus confirming our JE IgM serology. In fact, Unimas picked up two additional JE positives which were not detected by UH and Pan Bio Australia.

We even called in Prof Lam to discuss with our senior officers together with the Minister of Health and he assured us that we were definitely dealing with JE infection.

The head of CDC Atlanta, Dr Tom Kziazek, in his letter to the Ministry of Health on May 17, stated and I quote: "The viral encephalitis outbreak in Perak and Negri Sembilan included cases caused by two viruses, Japanese Encephalitis (JE) virus and a Hendra-like virus, now named the Nipah virus.

"The Malaysian Government instituted immediate control measures to reduce transmission of JE and this resulted in a reduction of JE cases.

"When further studies on the specimens received showed the presence of the Nipah virus, the Malaysian Government again acted promptly to control the outbreak by instituting universal precautionary measures such as face masks, gloves and gowns even though the exact mode of transmission had yet to be established.

"These measures were again successful and the number of new cases decreased rapidly and no additional cases of the Nipah virus have been reported in Perak and Negri Sembilan since April 21.

"Both the Ministry of Health and the CDC recognise that there was a preponderance of cases of Nipah virus during the present outbreak of viral encephalitis."

Hence you are incorrect in saying that despite lack of conclusive evidence that it was JE, the authorities staged JE vaccination programme for people living in high-risk zones.

Even pigs were vaccinated.

We were also encouraged in our decision by the fact that our statistics showed increasing percentage of patients were found positive serologically for JE.

In November last year we had 25% of cases positive and December 50% of cases positive serologically for JE.

However, we were not disheartened to see the positive rate drop to 36% in January, because that was how it should be with our massive control actions in place.

We knew that Bukit Pelandok was the largest pig farming area with highest density of pigs in Southeast Asia.

The first case of viral encephalitis was reported on Feb 23, despite the control measures have been instituted since Dec 4.

This time an arrangement was made with Hospital Seremban that all pathology specimens from patients from Bukit Pelanduk be sent to the University Hospital Virology Department Laboratory which is another WHO Collaborating Centre for Arboviruses for the Western Pacific Region.

In the meantime,we were made aware of the fact that by the end of January, our statistics showed that the positive rate for JE had fallen from 50 percent in December to 36 percent in January and 33.3% in February, and 9.4% in March.

While we said that our control measures were effective in controlling JE, we still see patients from Bukit Pelanduk coming into Hospital Seremban with signs and symptoms of encephalitis.

Our suspicion whether there was another type of infection on top of the JE viral infection was confirmed on March 5, when the Universiti Malaya Virology Department suspected a new virus found in the cerebrospinal fluid of one of the patients from Bukit Pelanduk.

Specimens were then sent to the Centres for Disease Control (CDC) in Atlanta, USA, and a new type of virus belonging to the family Paramyxovirus, not unsimilar to the to the Hendra Virus found in Australia, was confirmed on March 18.

It was named the Hendra-like virus and later the Nipah Virus.

From this time on we concentrated all our ef- forts in controlling the spread of this new virus while at the same time keeping at the back of our mind that there could still be JE infection.

The farmers must still keep their farms clean from potential breeding places for Culex mosquitoes.

The Ministry of Health immediately extended invitations to some of the scientists from CDC and the Commonwealth Scientific and Industrial Research Organisation (CSIRO).

On March 19, the public was told of the new virus and what precautions had to be taken to prevent the spread of this disease. Thousands of pamphlets in major languages were distributed to farmers, lorry drivers, abattoir workers and all persons related to the pig farming industry.

Face-to-face health education measures were given to thousands of people.

Up to now 468,989 pamphlets have been distributed, 21,6452 (?) health education sessions were held, and 19,262 workers in pig farms were personally examined and counselled by our Health officers.

The Government had taken very serious and fast actions in handling the outbreak. On March 17, a task force first chaired by the Minister of Health but later chaired by none other than the Deputy Prime Minister, with 10 ministers and deputy ministers, was immediately set up.

Meetings to review the progress were convened every week. A technical Committee chaired by the Director-General of Health with members from Director- Generals, physicians, virologists, Health experts, veterinary experts, from the Ministry of Health, Universiti Malaya, Veterinary Department and several other Ministries were also formed.

Meetings were held almost daily including Saturdays, Sundays and public holidays. The national operations room was set up to collect, coordinate and disseminate all information regarding the disease and the control measures taken.

It was opened 24 hours daily.

A website, and several hot-lines, were set up, with officers manning them round-the-clock.

This will enable the mass media and the general public access to all the information available.

Regular announcements were made through the media.

Up till now we have 258 cases with 101 deaths.

Of these 11 were confirmed JE, 27 have both JE and Nipah Virus, and 149 just Nipah Virus infections.

Sixty one cases are still awaiting results.

We humbly offer our condolences to the family of those who died.

We sympathise with those who have suffered.

The Ministry of Health congratulates and thanks the thousands of staff in Ministry of Health hospitals, University Hospital and private hospitals who had given time and energy in the past and perhaps in the future.

Their efforts were rewarded when 136 were discharged from hospitals.

Referring again to your article, you are incorrect to say that "not only is the disease rarely seen in adults, the JE virus also rarely shows visible signs in a patient.

"The high rate of deaths also did not match JE mortality rate of 10% to 50%, usually affecting victims who are either very young or very old."

The above could be true in ordinary endemic times as we see it in Sarawak but a study of 324 JE cases in Japan by Matsunaga et al showed 43 cases (13%) aged between 0-9 years, 30 cases (9%) aged between 10-39 years, 161 cases (50%) aged between 40-69 years and 90 cases (29%) aged above 70 years.

The highest incidence in male cases is in the age group of 50-59 years while in females it is in the 60-69 age grouping.

You also said that even those who received the full course of JE vaccination also succumbed tot he disease.

In any vaccination programme, 3% to 5% of those vaccinated will not have protection because of the physiological idiosyncracies in the persons concerned.

You are right when you said by the time the disease came to Bukit Pelanduk, the JE stand was highly questionable.

The Ministry of Health fully recognized the "JE positive" was very low.

It was only 10 days after the first case was reported in Bukit Pelanduk that we knew it was a new virus and we immediately instituted new strategies.

At the February JE conference in Ipoh, the ministry correctly stated that the otubreak was due to JE since the new virus was only discovered on March 5 and confirmed by CDC on March 18.

You are again incorrect in stating that the authorities still went all out to contain JE in the later stages especially in Negri Sembilan.

As mentioned above, all efforts to contain the new disease started the day the CDC confirmed the presence of the new virus.

The hundreds of thousands of pamphlets, posters and guidelines given to farmers, lorry drivers, farm workers and abattoir workers were distributed in all major languages in the same week.

We were very clear of our target and objectives, Dato' Dr Tee was right in stating that some people are wiser on hindsight.

It is not fair to criticize after everybody has given the answers.

The CDC team leader had denied the interview he gave to Reuters but instead had produced his own report as I had quoted above.

Dr Cardosa was quoted as saying that she offered to help analyse specimens from victims but received no response from the ministry.

We checked with all senior officers manning the Operations Room, but found no record she had offered to help.

As we always adopt an open policy for people sincerely wanting to help us, we would have certainly responded positively to her offer.

This I have done during the 1997 enterovirus outbreak in Sarawak when I personally went to her office in Unimas Sarawak to discuss how to implement her ideas.

I would have surely done the same this time if I had known at all she wanted to help.

After all, we were seeking help from all over the world.

To go to Asian Wall Street Journal is not the right thing to do.

Our main concern is to stop the spread of the disease and deaths among our people.

That is why we invited immediately all those who offered their services.

We agreed with Dr Kziazek and his remarks that "while there were some JE cases, it is clear to the CDC investigators that the predominant viral disease here is Nipah. The JE business is carried over from the early part. It's all behind us now. The numbers clearly show that it is Nipah."

That is exactly what we have been doing together with thousands of other staff, government officers, farm workers, and volunteers from the time we discovered the Nipah virus.

The ministry is surely not just trying to prove JE. We had also looked at all possibilities of other infections.

You mentioned that it was a waste of effort to vaccinate pigs and humans. On the contrary, the vaccination programme is a long-term strategy since JE is endemic in Malaysia.

The vaccination of pigs has been proven effective in Taiwan and Japan. We feel that what the Veterinary Department is doing is right.

It is clear from the scientific evidence before us that we are facing two infections from the JE virus and the Nipah virus. Both viruses cause viral encephalitis.

Even though the number of confirmed JE cases have been reduced, the control measures will still be in place. Control measures for the Nipah virus will have to be stepped up especially among the high risk groups.

The ministry will doing everything possible to ensure that the nation's health is protected.

We have to be prepared for emerging organisms which before this had not showed signs of virulence.

Man has to be vigilant and be prepared for anything.

It is however difficult to anticipate everything.

The best we can do is to act promptly and put into effect appropriate public health measures and treat cases actively when there are signs of an impending outbreak while waiting for confirmation of what the agent is and the exact cause of the outbreak.

This is what the ministry has done during the present outbreak and all that we have done has been fully supported by the WHO as shown in its press release on March 25.

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