2005 dengue outbreak in Singapore

Last updated

2005 dengue outbreak in Singapore
Disease Dengue fever
Virus strain Dengue virus
Location Singapore
Date 2005
Confirmed cases14,006 [1]
Severe cases381 [1]
Deaths
27 [1]
Fatality rate0.19% [1]
Government website
NEA Dengue Cases

In the 2005 dengue outbreak in Singapore, a significant rise in the number of dengue fever cases was reported in Singapore, becoming the country's worst health crisis since the 2003 SARS epidemic. In October 2005, there were signs that the dengue fever outbreak had peaked, as the number of weekly cases had declined and the outbreak of this infectious disease declined by the end of 2005.

Contents

Status of outbreak

The number of dengue fever cases per week in 2005. Between 18 June and 29 October, the number of weekly dengue fever cases exceeded the epidemic threshold of 237. 2005 weekly dengue cases.png
The number of dengue fever cases per week in 2005. Between 18 June and 29 October, the number of weekly dengue fever cases exceeded the epidemic threshold of 237.
Status (as of 31 December 2005)
Number of cases14,209 [2]
Number of deaths27 [1]

In 2005, there were a total of 14,209 dengue fever cases and 27 people died, a record death toll that would not be surpassed until 2020. [3] The outbreak peaked in the months of September and October, when it caused hospitals to cancel some elective surgery due to the need to allocate more beds for dengue patients.[ citation needed ]

Singapore's health-care system is helping to maintain a low fatality rate at 0.2% (2005), which is lower than Southeast Asia's regional average of 0.8% in 2004, according to the World Health Organization.[ citation needed ]

The National Environment Agency (NEA) said that the dengue fever problem may be worsening because of higher temperatures and changes in viral strains. The mean temperature has risen to 28.2 °C (82.8 °F) from 27.8 °C in 2003.[ citation needed ]

In the second week of September, more than 100 new cases were reported daily and many were admitted to public hospitals. [4]

Health Minister Khaw Boon Wan said that one of the concerns is that more Singaporeans are infected with Dengue Type 3, which is a new strain of the dengue virus.[ citation needed ]

Some experts, such as Dr Paul Reiter, Professor of Entomology at the Pasteur Institute in France, suggested that Singapore's success in suppressing the dengue has partly contributed to this year sudden increase in dengue cases. The population born over the last two decades has a low herd immunity and therefore more susceptible to the virus. [5]

In January 2006, Environment and Water Resources Minister Yaacob Ibrahim declared the dengue outbreak is under control with average 84 cases weekly compared to a peak of more than 700. [6]

Inter-ministerial and inter-agency committees

Dengue hotspots: geographical distribution of dengue cases. Dengue hotspot.png
Dengue hotspots: geographical distribution of dengue cases.
Larva of Aedes aegypti mosquito, the primary vector for dengue. Aedes aegypti larva.jpg
Larva of Aedes aegypti mosquito, the primary vector for dengue.

In September, an inter-ministerial committee headed by Minister for the Environment and Water Resources, Yaacob Ibrahim, was formed to tackle the dengue outbreak. Yaacob Ibrahim delivered a ministerial statement on the issue in the parliament on 19 September. [7]

An inter-agency Dengue Coordination Committee and a community-centred Dengue Watch Committee have also been established. [8] The Dengue Coordination Committee involves the permanent secretaries of the Environment, Health, and National Development ministries, and Chief Executive Officers of key government statutory boards, and it aims to ensure that the various policy initiatives by the various ministries are well-coordinated. Land Transport Authority (LTA) would make sure that bus-stops, Mass Rapid Transit stations, construction sites are free of mosquito breeding. Singapore Land Authority (SLA) were also stepping up their checks on vacant state land and properties, while the Housing and Development Board (HDB) and town councils are stepping up the cleaning of common areas. [9]

The Dengue Watch Committee is chaired by Khoo Tsai Kee who is the Senior Parliamentary Secretary for the Environment and Water Resources. He will co-ordinate with the five mayors in Singapore to reach out to the 84 advisers and the town councils, to oversee dengue prevention measures at the community level.[ citation needed ]

A panel of experts had also been set up to advise the government on anti-dengue measures. The panel is chaired by Dr Chee Yam Cheng, Clinical Professor and Assistant chief executive officer of National Healthcare Group.[ citation needed ]

Preventive measures

Larvae in stagnant water Mosquito larvae.jpg
Larvae in stagnant water

Singapore launched a number of measures to contain the dengue outbreak, including public awareness campaigns and regular fogging with insecticides. 4,200 volunteers, 970 environmental control officers hired by construction sites, 350 so-called "mozzie busters" made up of girl guides and scouts, have participated in the preventive efforts.[ citation needed ]

The Ministry of Health stepped up its monitoring of common mosquito breeding sites and launched an online map listing "hotspots" for the insects. Residents who allow mosquitoes to breed in their homes can be fined between S$100 to S$200, and heavier penalties may be issued for construction sites found with standing water. The number of officers conducting such checks have tripled since the start of the year to 360, and may increase to 510 by December.[ citation needed ]

The National Environment Agency has allocated an additional S$7.5 million on top of its existing S$2.5 million budget to clear drains of stagnant water where mosquitoes breed. Singapore Land Authority has also stepped up its checks on vacant state properties.[ citation needed ]

On 10 September, National Environment Agency started collecting blood samples from residents of Sims Avenue, a dengue hotspot, to help track the infection. The residents were asked to provide voluntarily 5 millilitres of blood sample and a swab of saliva for the study. The samples were to be analysed for antibodies against dengue infection in the last 2 months. [4]

The National Parks Board (NParks) is considering removing broad-leafed plants which may breed mosquitoes. [10] These plants like palm trees or any plants with axils capable of trapping water, are potential breeding sites. [10] Some town councils had removed some or all palm trees in their jurisdictions. [10] Additional trimming of palm trees had been done by NParks to reduce potential breeding sites. [10] As holes in tree trunks are also a concern, NParks had regularly filling these holes with sands. [10] NParks has engaged 16 pest companies to prevent mosquito breeding in the parks it manages. [10] Due to the dengue threat, some schools are cancelling excursions to the parks. [10]

By end of October, town councils are to employ dedicated pest control officers and engage in more frequent drain cleanings. [11]

Community response

Health Minister Khaw Boon Wan urged the public to help in the fight against the disease. As households are common breeding grounds for mosquitos and are less accessible for fogging, residents can help by checking for stagnant water in their households and neighbourhood and ensuring no blockage of drains. Due to the short life cycle of Aedes aegypti mosquitos (7 to 10 days), frequent checks are necessary to eradicate dengue. These checks only take several minutes and could potentially save lives.[ citation needed ]

Dr Kevin Palmer, World Health Organization's regional adviser for mosquito-borne diseases, said that it is important for ordinary residents to play their part. He added that fogging alone was not effective as winds could blow the insecticide away. [12] Yaacob Ibrahim also said that fogging only kills adult mosquitoes, but not the larva and therefore less effective compared to removing breeding sites. [13]

Singapore residents are also arming themselves with anti-mosquito products including insecticides, repellents and electronic mosquito traps. For repellents, experts are recommending those with an active ingredients, such as DEET which provide more effective and lasting protection.[ citation needed ]

As a preventive measure, some residents bought a perennial grass plant, Citronella, and placing it at their home to repel mosquitos. [14] The plant gives off a strong lemon-like fragrance which supposedly repels mosquitoes. [14]

To prevent the spread of the virus, those who are already infected with dengue are encouraged to use mosquito repellents, wear long-sleeved clothing and sleep under mosquito nets to prevent mosquitoes from biting them again and spreading the virus to others.[ citation needed ]

Weekend blitz

Minister for the Environment and Water Resources Yaacob Ibrahim informed Parliament that NEA officers with volunteers would conduct weekend blitz campaigns over six weeks, covering all estates, to destroy mosquito-breeding sites. [11]

First blitz, 17–18 September

On the weekend of 17–18 September, more than 700 officers and volunteers launched a house-to-house campaign to remove breeding sites at four neighbourhoods, in what Minister Mah Bow Tan described as "sort of a carpet-combing exercise". The four neighbourhoods involved in the weekend blitz are Ang Mo Kio, Yishun, Hougang and Marsiling, which are among the worst affected regions.[ citation needed ]

In this "search-and-destroy" operation, mosquito-fighting "commandos" combed the streets, checked the drains, looked at the bins and the roof structures at all estates to seek and destroy breeding sites. They found 172 mosquito-breeding sites, mainly flower pot trays, water containers, litter in open area and tree holes. [11]

Second blitz, 24–25 September

In the following weekend, the blitz was continued and covered five other areas such as Toa Payoh/Bishan, Tampines, Choa Chu Kang, Bedok and Boon Lay/Jurong, and 220 breeding sites were found and destroyed. [15]

Third blitz, 1–2 October

More than one thousand volunteers were involved in this third blitz to cover areas including Kallang, West Coast and Jurong East. 187 breeding sites were found and removed. [16]

Treatment

In September, Singapore experienced a drastic rise of dengue cases. In the first week alone, 547 new cases were reported and many required hospital care. As the treatment lasts about 10 days, many hospitals across Singapore are experiencing shortage of hospitals beds. To cope with the strain, hospitals are postponing non-emergency operations to accommodate the dengue patients. [17]

General practitioners and polyclinics are on high alert to check for cases of dengue and are ordering more patients to have their blood tested for suspected dengue. The test, which takes fifteen minutes, is based on platelet count; dengue sufferers have 100,000 or lower platelet count as compared to 140,000 to 400,000 of a healthy person. If a suspected dengue patient is diagnosed, the patient will be referred to a hospital for more accurate testing.[ citation needed ]

Dengue diagnostic kits

In July 2005, a Singapore life science start-up company Veredus Laboratories launched a DNA- and RNA-based diagnostic kits for dengue, avian influenza and malaria. The kit is based on technologies licensed from A*STAR and the National University of Singapore. [18]

Another Singapore company Attogenix Biosystems has also developed a biochip called AttoChip which has successfully undergone an independent clinical trial conducted by Tan Tock Seng Hospital and is 98 percent accurate. The AttoChip identifies genes, viruses and bacteria-causing diseases from a blood sample. It can detect the presence of the dengue virus within two to three days of the onset of the virus. [19] [20]

See also

Related Research Articles

<span class="mw-page-title-main">Yellow fever</span> Viral disease common in tropical Africa and South America

Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased.

<span class="mw-page-title-main">Dengue fever</span> Tropical disease caused by the dengue virus, transmitted by mosquito

Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin itching and skin rash. Recovery generally takes two to seven days. In a small proportion of cases, the disease develops into a more severe dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.

<i>Aedes albopictus</i> Species of mosquito

Aedes albopictus, from the mosquito (Culicidae) family, also known as the (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia. In the past few centuries, however, this species has spread to many countries through the transport of goods and international travel. It is characterized by the white bands on its legs and body.

<span class="mw-page-title-main">Arbovirus</span> Common name for several species of virus

Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.

<span class="mw-page-title-main">Singapore Green Plan 2012</span>

Singapore Green Plan 2012 was released in 2002 by the Ministry of the Environment and Water Resources (MEWR) as a continuation of the Singapore Green Plan first issued in 1992. Comprising eight distinct key measures, SGP 2012 aims to create an environmentally-conscious Singapore, promoting conservation of the nation's natural resources and the use of green technology to conserve the environment, both locally and globally. It also aims to ensure sustainability in the country's development and to instill within Singaporeans personal duty and commitment towards the environment.

<span class="mw-page-title-main">National Environment Agency</span> Government agency of Singapore

National Environment Agency (NEA) is a statutory board under the Ministry of Sustainability and the Environment of the Government of Singapore.

<span class="mw-page-title-main">Epidemiology of chikungunya</span>

Chikungunya is a mosquito-borne alpha virus that was first isolated after a 1952 outbreak in modern-day Tanzania. The virus has circulated in forested regions of sub-Saharan African in cycles involving nonhuman primate hosts and arboreal mosquito vectors. Phylogenetic studies indicate that the urban transmission cycle—the transmission of a pathogen between humans and mosquitoes that exist in urban environments—was established on multiple occasions from strains occurring on the eastern half of Africa in non-human primate hosts. This emergence and spread beyond Africa may have started as early as the 18th century. Currently, available data does not indicate whether the introduction of chikungunya into Asia occurred in the 19th century or more recently, but this epidemic Asian strain causes outbreaks in India and continues to circulate in Southeast Asia.

<span class="mw-page-title-main">Health in Singapore</span>

Singapore is one of the wealthiest countries in the world, with a gross domestic product (GDP) per capita of more than $57,000. Life expectancy at birth is 82.3 and infant mortality is 2.7 per 1000 live births. The population is ageing and by 2030, 20% will be over 65. However it is estimated that about 85% of those over 65 are healthy and reasonably active. Singapore has a universal health care system.

<i>Zika virus</i> Species of flavivirus

Zika virus is a member of the virus family Flaviviridae. It is spread by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Ziika Forest of Uganda, where the virus was first isolated in 1947. Zika virus shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–2016 Zika virus epidemic.

<span class="mw-page-title-main">Dengue fever outbreaks</span> Disease outbreak

As of 2010, dengue fever is believed to infect 50 to 100 million people worldwide a year with 1/2 million life-threatening infections. It dramatically increased in frequency between 1960 and 2010, by 30 fold. This increase is believed to be due to a combination of urbanization, population growth, increased international travel, and global warming. The geographical distribution is around the equator with 70% of the total 2.5 billion people living in endemic areas from Asia and the Pacific. Many of the infected people during outbreaks are not virally tested, therefore their infections may also be due to chikungunya, a coinfection of both, or even other similar viruses.

Dengue fever is an important infectious disease in Pakistan with increasingly frequent epidemics. Despite the efforts of the Government of Pakistan, especially in Punjab, the high cost of prevention has limited the ability of Pakistan to control epidemics. In Pakistan, in the summer of 2011, more than 300 people died of Dengue fever. The prevalence of the disease was over 14,000. The outbreaks occurred mostly in the Lahore area, Punjab, Pakistan.

In the 2013 dengue outbreak in Singapore, a significant rise in the number of dengue fever cases was reported in Singapore. The outbreak began in January, with the number of infections beginning to surge in April, before eventually reaching a peak of 842 dengue cases in the week of 16–22 June 2013. This figure was far beyond the highest number of cases per week in the previous three years. Although there were concerns that the rate of infection could exceed 1,000 per week, these fears did not materialize.

<span class="mw-page-title-main">Lethal ovitrap</span> Mosquito-killing trap

A lethal ovitrap is a device which attracts gravid female container-breeding mosquitoes and kills them. The traps halt the insect's life cycle by killing adult insects and stopping reproduction. The original use of ovitraps was to monitor the spread and density of Aedes and other container-breeding mosquito populations by collecting eggs which could be counted, or hatched to identify the types of insects. Since its conception, researchers found that adding lethal substances to the ovitraps could control the populations of these targeted species. These traps are called lethal ovitraps. They primarily target Aedes aegypti and Aedes albopictus mosquitoes, which are the main vectors of dengue fever, Zika virus, west Nile virus, yellow fever, and chikungunya.

The 2013–2014 chikungunya outbreak represented the first recorded outbreak of the disease outside of tropical Africa and Asia. In December 2013, the first locally transmitted case of chikungunya in the Americas was detected in Saint Martin. Shortly after the first case the disease began to spread rapidly throughout the Caribbean region. By the end of the year, it had spread to Martinique and Guadeloupe, with suspected cases in Saint Barthélemy. By the end of January 2014, cases had been confirmed in Saint Barthélemy, as well as the British Virgin Islands, Dominica, and French Guiana. On the basis of 4,000 confirmed cases and over 30,000 suspected cases, the Caribbean Public Health Agency (CARPHA) declared a Caribbean-wide epidemic of the virus in early May. By the end of May, four cases of chikungunya had been confirmed in Florida. By July 2014 there were an estimated 355,000 cases in the Caribbean. By August 2014, 25 Caribbean countries had confirmed at least one case. The epidemic was over by 2015.

<span class="mw-page-title-main">2015–16 Zika virus epidemic</span> Widespread epidemic of Zika fever

An epidemic of Zika fever, caused by Zika virus, began in Brazil and affected other countries in the Americas from April 2015 to November 2016. The World Health Organization (WHO) declared the end of the epidemic in November 2016, but noted that the virus still represents "a highly significant and long term problem". It is estimated that 1.5 million people were infected by Zika virus in Brazil, with over 3,500 cases of infant microcephaly reported between October 2015 and January 2016. The epidemic also affected other parts of South and North America, as well as several islands in the Pacific.

In October 2013, there was an outbreak of Zika fever in French Polynesia, the first outbreak of several Zika outbreaks across Oceania. With 8,723 cases reported, it was the largest outbreak of Zika fever before the outbreak in the Americas that began in April 2015. An earlier outbreak occurred on Yap Island in the Federated States of Micronesia in 2007, but it is thought that the 2013–2014 outbreak involved an independent introduction of the Zika virus from Southeast Asia. Investigators suggested that the outbreaks of mosquito-borne diseases in the Pacific from 2012 to 2014 were "the early stages of a wave that will continue for several years", particularly because of their vulnerability to infectious diseases stemming from isolation and immunologically naive populations.

<span class="mw-page-title-main">Zika virus outbreak timeline</span>

This article primarily covers the chronology of the 2015–16 Zika virus epidemic. Flag icons denote the first announcements of confirmed cases by the respective nation-states, their first deaths, and relevant sessions and announcements of the World Health Organization (WHO), and the U.S. Centers for Disease Control (CDC), as well as relevant virological, epidemiological, and entomological studies.

<span class="mw-page-title-main">2019–2020 dengue fever epidemic</span> Dengue fever epidemic in 2019–2020

The 2019–2020 dengue fever epidemic was an epidemic of the infectious disease dengue fever in several countries of Southeast Asia, including the Philippines, Malaysia, Vietnam, and Bangladesh, Pakistan, India, Thailand, Singapore, and Laos. The spread of the disease was exacerbated by falling vaccination levels in certain areas, and by a growing population of mosquitoes, which are the primary carriers of the disease, and which are able to reproduce in larger numbers where humans have littered the environment with plastic containers, which provide an ideal breeding ground for mosquitoes. Affected countries have sought to control the epidemic through increased vaccination efforts, and through efforts to control the mosquito population.

<span class="mw-page-title-main">Climate change and infectious diseases</span> Overview of the relationship between climate change and infectious diseases

Global climate change has resulted in a wide range of impacts on the spread of infectious diseases. Like other ways in which climate change affects on human health, climate change exacerbates existing inequalities and challenges in managing infectious disease. Infectious diseases whose transmission can be impacted by climate change include dengue fever, malaria, tick-borne diseases, leishmaniasis and Ebola virus disease. For example, climate change is altering the geographic range and seasonality of the mosquito that can carry dengue.

In the 2020 dengue outbreak in Singapore, a record-breaking number of dengue fever cases was reported in Singapore. This was part of the wider 2019–2020 dengue fever epidemic which also affected several neighbouring countries in Southeast Asia.

References

  1. 1 2 3 4 5 Koh, Benjamin K. W.; Ng, Lee Ching; Kita, Yuske; Tang, Choon Siang; Ang, Li Wei; Wong, Kit Yin; James, Lyn; Goh, Kee Tai (July 2008). "The 2005 dengue epidemic in Singapore: epidemiology, prevention and control". Annals of the Academy of Medicine, Singapore. 37 (7): 538–545. ISSN   0304-4602. PMID   18695764.
  2. "Dengue cases down for 4th week in a row". TODAY. 29 July 2013.
  3. Ng, Keng Gene (14 October 2020). "28 people have died of dengue this year, a new high that now matches the Covid-19 death toll". The Straits Times.
  4. 1 2 Ng, Julia (10 September 2005). "Another 125 dengue cases reported, 85 admitted to hospital". Channel NewsAsia . Archived from the original on 2 December 2005. Retrieved 30 March 2023.
  5. "Singapore's dengue outbreak has peaked: experts". Archived from the original on 20 February 2006. Retrieved 13 October 2005.
  6. "Environment Minister says dengue situation under control". Channel NewsAsia . 8 January 2006. Archived from the original on 1 October 2007. Retrieved 30 March 2023.
  7. "Inter-ministerial panel formed to tackle Singapore's dengue situation". Archived from the original on 1 October 2007. Retrieved 9 September 2005.
  8. "Inter-agency panel, watch group set up to tackle rising dengue cases". Archived from the original on 28 November 2005. Retrieved 12 September 2005.
  9. "SLA doubles dengue checks on vacant state properties". Archived from the original on 25 November 2005. Retrieved 4 December 2018.
  10. 1 2 3 4 5 6 7 Forss, Pearl (15 September 2005). "NParks considers removing trees, plants which may breed mosquitoes". Channel NewsAsia . Archived from the original on 1 December 2005. Retrieved 30 March 2023.
  11. 1 2 3 Margaret, Perry (19 September 2005). "Mosquito-breeding sites found at one in 10 housing blocks". Channel NewsAsia . Archived from the original on 1 December 2005. Retrieved 30 March 2023.
  12. "WHO'S verdict on S'pore BEST DENGUE DEFENCE IN THE WORLD WORST DENGUE OUTBREAK IN THE WORLD". 10 November 2005. Archived from the original on 10 November 2005.
  13. "ENV to study how fogging practices are conducted". Archived from the original on 9 December 2005. Retrieved 12 September 2005.
  14. 1 2 Wong, May (18 September 2005). "Singaporeans snap up Citronella to repel mosquitoes". Channel NewsAsia . Archived from the original on 5 December 2005. Retrieved 30 March 2023.
  15. Margaret, Perry (28 September 2005). "Another person dies from dengue, bringing death toll to 12 this year". Channel NewsAsia . Archived from the original on 1 December 2005. Retrieved 30 March 2023.
  16. "1,000 volunteers to go on third anti-dengue blitz this weekend". Archived from the original on 24 November 2005. Retrieved 1 October 2005.
  17. "Non-urgent operations delayed as hospitals cope with dengue cases". Archived from the original on 25 November 2005. Retrieved 4 December 2018.
  18. "Singapore start-up firm launches avian flu, dengue diagnostic kits". Archived from the original on 26 November 2005. Retrieved 10 September 2005.
  19. "Thanks to local firm, dengue detection's now 98% accurate". 26 October 2005. Archived from the original on 26 October 2005.
  20. "Clinical Trial Results of Attochip (Dengue Biochip)". archive.is. 18 May 2006. Archived from the original on 18 May 2006.

Further reading