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Kenyataan Akhbar KPK 22 November 2019 – Keberkesanan Teknik Inovatif Kawalan Denggi dengan Menggunakan Nyamuk Aedes Aegypti Berwolbachia

Para saintis telah melaporkan kaedah yang berkesan dan mesra alam untuk menyekat penularan virus denggi yang dibawa oleh nyamuk Aedes aegypti. Wolbachia merupakan symbion bakteria yang wujud secara meluas dalam serangga. Penggunaan Aedes aegypti berWolbachia adalah kaedah mampan dan inovatif untuk mengawal penyakit bawaan nyamuk Aedes.

Aedes berwolbachia

Penyelidik-penyelidik daripada Unit Kajiserangga Perubatan, Institut Penyelidikan Perubatan (IMR), Kementerian Kesihatan Malaysia (KKM), bersama-sama dengan penyelidik di Universiti Glasgow (UK) dan Universiti Melbourne (Australia) telah berjaya mengurangkan kes denggi di lokaliti hotspot denggi di negeri Selangor dengan menggunakan bakteria Wolbachia ini. Wolbachia mampu menghalang nyamuk Aedes aegypti daripada menyebarkan virus denggi kepada manusia. Hasil penyelidikan yang telah diterbitkan dalam jurnal Current Biology  pada 21 November 2019 menunjukkan bahawa nyamuk berWolbachia (strain wAlbB) apabila dilepaskan ke alam sekitar berkesan mengurangkan hampir 40% kes demam denggi. Selain denggi, Wolbachia (strain wAlbB) juga berkesan dalam menyekat penularan virus Zika dan chikungunya yang disebarkan melalui nyamuk.

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Sebelum ini, para saintis di luar negara telah menjalankan pelepasan nyamuk berWolbachia dengan menggunakan strain yang berbeza. Namun keberkesanan strain tersebut adalah tidak setara strain wAlbB, di mana strain wAlbB adalah lebih sesuai digunakan di negara tropika yang bersuhu panas seperti Malaysia.

Di Malaysia, lebih 100,000 kes demam denggi dilaporkan pada 2016 dengan kos tahunan dianggarkan USD 175 juta. Bagi tahun 2019, jumlah kes denggi dari Januari hingga 16 November 2019 berjumlah 114,745 kes iaitu peningkatan sebanyak 48,175 kes (72.4%) berbanding 66,570 kes pada jangkamasa yang sama pada tahun 2018. Sekitar 1% kes merupakan kes demam denggi berdarah yang mengancam nyawa atau shock syndrome. Ketiadaan vaksin dan rawatan anti-virus yang efektif menyebabkan penyakit denggi tersebar ke seluruh dunia secara mendadak.

Pada fasa awal penyelidikan, para penyelidik telah melepaskan nyamuk Aedes berWolbachia (strain wAlbB) di 6 lokaliti iaitu AU2 Keramat, PKNS AU2 Keramat, Seksyen 7 Shah Alam, Flat PKNS, Jalan Plumbum 101/103 Shah Alam, Mentari Court  dan  Pusat Komersial Seksyen 7 yang merupakan lokaliti hotspot denggi berterusan. Nyamuk Aedes berWolbachia jantan dan betina yang dilepaskan akan mengawan dengan nyamuk liar di lapangan. Hasil daripada pengawanan ini akan menyebabkan Wolbachia tersebar di dalam populasi nyamuk lapangan yang seterusnya akan menghentikan penularan demam denggi. Di sesetengah lokaliti, frekuensi nyamuk berWolbachia telah mencapai tahap 90% selepas pelepasan dihentikan lebih daripada setahun.

Kejayaan menurunkan kes demam denggi di lokaliti-lokaliti pelepasan nyamuk berWolbachia telah menyebabkan tiada lagi penggunaan racun serangga sekaligus memberi manfaat pada alam sekitar dan ekonomi negara.

Berikutan kejayaan dan impak yang memberangsangkan dalam menurunkan kes demam denggi, Bahagian Kawalan Penyakit KKM bersama-sama dengan IMR, Makmal Kesihatan Awam Kebangsaan, Bahagian Pendidikan Kesihatan, Institut Penyelidikan Tingkahlaku Kesihatan, Jabatan Kesihatan Negeri, Pejabat Kesihatan Daerah, Pihak Berkuasa Tempatan, Kerajaan Negeri dan komuniti kini telah menjalankan operasi pelepasan Aedes berWolbachia ke kawasan hotspot denggi lain di Selangor, Kuala Lumpur dan Pulau Pinang.

KKM dengan ikhlas menghargai dan merasa bangga di atas penglibatan, sumbangan dan kerjasama sepadu oleh komuniti-komuniti di lokaliti pelepasan nyamuk Aedes berWolbachia untuk menjayakan projek ini.

Kertas penyelidikan bertajuk ‘Establishment of Wolbachia strain wAlbB in Malaysian populations of Aedes aegypti for dengue control’ telah diterbitkan di jurnal Current Biology dan boleh didapati di https://www.cell.com/current-biology/fulltext/S0960-9822(19)31446-0 . Kajian ini telah dibiayai oleh Wellcome Trust, National Health and Medical Research Council of Australia Awards dan Kementerian Kesihatan Malaysia.

 

DATUK DR. NOOR HISHAM BIN ABDULLAH

Ketua Pengarah Kesihatan Malaysia

22 November  2019

 


Press Statement

Director General Of Health Malaysia

 Aedes Aegypti Carrying Wolbachia Bacteria A Biologically Viable Tool

For Dengue Control

 

Scientists have reported an effective and environmentally sustainable way to block the transmission of the mosquito-borne dengue virus, in field trials carried out in Malaysia. Wolbachia, a widespread bacterial symbiont of insects, has emerged as a viable tool to control Aedes borne diseases.

Using a strain of the bacteria Wolbachia, which inhibits mosquitoes from transmitting viruses to human, researchers at the Medical Entomology Unit, Institute for Medical Research (IMR), Ministry of Health Malaysia (MOH), together with the Universities of Glasgow (UK) and Melbourne (Australia) were successfully able to reduce cases of dengue at dengue hotspot sites in the state of Selangor. Their data, published on 21 November 2019 in the peer-reviewed journal Current Biology, shows that mosquitoes carrying the wAlbB strain of Wolbachia, when released into the environment, had the effect of reducing the incidence of dengue cases by at least 40%. Besides dengue, the wAlbB strain of Wolbachia is also effective in blocking transmission of other mosquito borne viruses including Zika and chikungunya.

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Previously, scientists elsewhere, have carried out successful mosquito releases using a different strain of Wolbachia, but while this strain was effective in some conditions, it did not appear to be suitable for use in the hot tropical conditions experienced in Malaysia.

In Malaysia, over 100,000 dengue cases were reported in 2016 with an annual cost estimated at USD 175 million. For 2019, the total number of dengue cases between January to 16 November 2019 reached 114,745 cases which is an increase of 48,175 cases (72.4%) compared to 66,570 cases during the same period in 2018. Severe disease occurs in around 1% of cases, including life-threatening haemorrhage or shock syndrome. In the absence of an effective vaccine and anti-viral treatment, the scourge of dengue is rapidly spreading globally.

Researchers released batches of Aedes aegypti mosquitoes carrying the wAlbB strain of Wolbachia into the environment in 6 different sites initially, namely AU2 Keramat, PKNS AU2 Keramat, Shah Alam Section 7, Flat PKNS, Jalan Plumbum 101/103 Shah Alam, Mentari Court  and  Pusat Komersial Section 7 with previously high levels of dengue transmission. The Wolbachia carrying mosquitoes – both male and female – then went on to mate with the wild mosquito population, resulting in the spread and establishment of the virus-inhibiting bacteria. In some sites, Wolbachia-carrying mosquitoes were measured at over 90% frequency more than a year after the mosquito releases ended.

The success of lowering dengue cases at these sites has led to a cessation of insecticide fogging in these areas, highlighting both the environmental and economic benefits of this method.

Seeing the promising impact in the initial releases and impressed by the evident success of this trial, the MOH’s Disease Control Division together with IMR, National Public Health Laboratory, Health Education Division, Institute for Health Behavioural Research, State Health Departments, District Health Offices, local authorities, State Governments and communities are now recruiting Aedes aegypti carrying Wolbachia operationally and extending this approach into different dengue persistent hotspots in Selangor, Kuala Lumpur and Penang.

With sincere appreciation, we proudly recognise and honour the outstanding contributions of the members of the community in the trial sites, who with their dedicated efforts and generous cooperation helped to ensure the success of the project.

The paper, ‘Establishment of Wolbachia strain wAlbB in Malaysian populations of Aedes aegypti for dengue control’ is published in Current Biology and available at https://www.cell.com/current-biology/fulltext/S0960-9822(19)31446-0 .The study was funded by the Wellcome Trust, National Health and Medical Research Council of Australia Awards and the Ministry of Health Malaysia.

 

DATUK DR. NOOR HISHAM BIN ABDULLAH

Director General of Health Malaysia

22 November 2019

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