No delay in malaria notification, says MOH

22 Jun 2009, The Straits Times

Question

Malaria: Why is action so slow in coming?

Delay in notifying the mosquito-busters can result in more cases

DOCTORS are required by law, on pain of a fine and/or a jail term, to alert the Ministry of Health (MOH) within 24 hours of diagnosing a patient with certain infectious diseases.

This is so that the authorities can swoop in and nip the spread of these diseases - such as mosquito-borne ones like dengue, malaria and chikungunya - in the bud.

To be effective, notification must be prompt and follow-up action immediate.

The current outbreak of malaria has raised questions as to whether the notification system is imbued with enough sense of urgency.

By the time the National Environment Agency (NEA) activated its mosquito-busters, at least 17 more people had become infected.

Why did it take two to three weeks after Patient Zero surfaced for the NEA to swing into action?

An NEA spokesman said the agency was told of the Jurong cluster on May 25 - 22 days after the first patient there showed symptoms of malaria. It moved in with its search-and-destroy team the next day.

As for the Mandai cluster, it got the news on May 29, 13 days after the first patient there became ill. Fogging began the next day.

This is not the first time that a time lag between symptoms appearing in the first patient and NEA being told has resulted in more infections.

Singapore's fight against chikungunya last year was also bugged by similar delays.

It is difficult to ascertain how many of the more than 100 locally-transmitted chikungunya cases last year, and the 250 so far this year, can be traced to the slow eradication of Aedes mosquitoes in the affected areas. But the existence of clusters of cases suggests that delay played a role in the spread of the disease.

The fact that a doctor's failure to inform MOH of a notifiable disease like malaria within 24 hours could land him in jail for up to six months and/or a fine of up to $10,000 is indication enough that the law views the spread of such diseases seriously. Why then the delay?

The question has been posed to MOH several times, but no answer has been forthcoming.

The lapses appear to be in the reporting system. Either doctors are not reporting cases early enough, laboratories are taking too long to revert with test results, or ministry officials are not following up on tip-offs as quickly as they should.

Malaria is transmitted from patient to patient via mosquito bites. When someone is infected and symptoms appear, it means that the person has the malaria-bearing parasite in his blood.

The biting is done by the female Anopheles mosquito, which requires blood meals to go into breeding mode. A mosquito which picks up the parasites from the blood of an infected person passes them on to the next person it bites.

The only way to break the chain of transmission is to ensure that the patient is not bitten while still infectious. This means the patient either has to be kept in air-conditioned isolation and away from all insects, or all Anopheles mosquitoes in the vicinity have to be killed, and their breeding places destroyed.

In the recent outbreaks, people were getting infected and falling ill over a period of almost a month. This means several patients - and mosquitoes - were involved in spreading the disease.

The NEA is confident that it has wiped out the Anopheles mosquito in Jurong and Mandai, so there should not be any more infections there. If they had been alerted earlier, some of the victims could have been spared the fever, headache, chills and vomiting that come with malaria.

Laxity in reacting could see both malaria and chikungunya become endemic here - the way dengue already is. If they do become endemic, the fight to keep people from falling ill with these diseases will become more difficult.

Worldwide, about 240 million people are infected with malaria each year, and a million die from it.

Chikungunya rarely kills, but the illness is more severe than dengue. Its victims suffer from severe joint aches that can last weeks or even months.

Health Minister Khaw Boon Wan has warned that Singapore should not 'belittle' this malaria outbreak.

But perhaps Singapore's malaria-free status for the past 27 years has bred a certain complacency, and chikungunya is relatively new. As a result, neither disease was on our radar screen, unlike dengue, which has been around for some time

But as Mr Khaw noted, it took a lot of effort for Singapore to become malaria-free. If the disease takes root here as dengue has, it will take a long time to eradicate it again.

Everyone - doctors, lab technicians and government officials - needs to take these diseases more seriously, and take action as soon as the diseases are detected.

Every citizen and resident in the country has a role to play too, since dengue, malaria and chikungunya are all spread by mosquitoes: Be assiduous in preventing this insect from breeding in the first place and none of these diseases will be able to spread.

No one is immune. The next person to be bitten by an infected mosquito could well be you.

Reply

Reply from MOH 

LAST Thursday's column, 'Malaria: Why is action so slow in coming?', questioned the time lag before the two malaria outbreaks were notified by the Ministry of Health (MOH) to the National Environment Agency (NEA).

The writer was concerned as any delay in notification would affect NEA's mosquito eradication efforts.

In the Jurong Island cluster, the first patient was diagnosed on May 12 by his doctor, who notified MOH on May 13. The second patient was diagnosed and notified to MOH on May 18.

Two notifications would trigger an epidemiological investigation but do not necessarily imply a local transmission. This is because malaria cases here are virtually all imported and foreign workers are particularly susceptible to the disease which could recur from time to time.

Hence, unlike dengue where every notification will trigger an immediate vector control operation by NEA, MOH needs to conduct epidemiological investigations to determine any local malaria transmission. This requires meticulous field investigations and will typically take several days.

In the Mandai-Sungei Kadut cluster, the first notification to MOH was on May23. The second notification was on May 24, triggering the epidemiological investigations of that cluster.

MOH treats the possible re-emergence of malaria in Singapore very seriously. In these two instances, there was no undue delay in notification. There was, however, a delay of several days as the patients did not seek immediate medical attention.