Could one bite transmit dengue and chikungunya?

Could one bite transmit two viruses?
NEA to study mosquitoes' ability to transmit dengue and chikungunya at the same time
Lee Hui Chieh, Straits Times 25 Jan 08;

RESEARCHERS here will study local mosquitos in a bid to uncover whether the insects can transmit dengue and a similar disease, chikungunya, at the same time.

Singapore is in the midst of its first outbreak of chikungunya, with at least 10 people infected in the last two weeks.

Dengue, which is endemic here, has infected 390 people so far this year.

Scientists at the National Environment Agency's Environmental Health Institute know that both humans and the Aedes mosquito can be infected with dengue and chikungunya at the same time.

What is not clear is whether the mosquito can transmit both viruses with one bite, said the institute's senior research scientist Christina Liew, an expert on disease-carrying insects.

A mosquito's ability to spread diseases can differ according to its genetic structure, its home territory and even the temperature of its surroundings, Dr Liew said.

Researchers have found mosquitoes in the wild in Maharashtra, India, carrying both the dengue and the chikungunya viruses.

Laboratory studies have also found that mosquitoes can be infected with both viruses at the same time. Scientists, however, were unable to determine if both diseases can be transmitted simultaneously.

Unlucky patients have been hit with the double whammy of dengue and chikungunya, though.

Studies have reported that 1.7 to 3 per cent of the patients in India's 2006 chikungunya epidemic were infected with both diseases.

They could have been bitten by just one mosquito carrying both viruses or by two different mosquitoes.

Both dengue and chikungunya cause similar symptoms such as fever, joint pains, chills, nausea and vomiting.

Chikungunya symptoms usually last three to 10 days, but the joint pain can last for weeks or months.

Chikungunya appears to have a shorter incubation period in mosquitoes and humans.

It takes three to five days to incubate in mosquitoes and one to 12 days in humans, compared to dengue's eight to 12 days in mosquitoes and three to 14 days in humans.

There is some consolation for patients with either disease. While deaths have been reported, they are rare.

All quiet on Clive St
A spate of chikungunya cases has left this street in Little India half-empty

Loh Chee Kong, Today Online 25 Jan 08;

A PALPABLE air of unease filled what was usually a walkway brimming with tourists and eager shoppers looking for a good bargain along the rows of shops selling anything from pre-paid phone cards to handicrafts.

At Clive Street yesterday afternoon — 10 days after Singapore's first locally-transmitted case of chikungunya fever was detected here — the street was half-empty and a couple of eating houses were closed. Regular patrons and visitors seem to have been scared away by the outbreak and the media coverage of this new health threat.

There were sporadic activities — although different from the kind you would expect on a street in bustling Little India: Shopkeepers cleaning their wares, pest controllers prowling the back alleys and bored stall assistants gathering outside for a quick puff and chat.

So far, 10 cases of chikungunya fever, which is transmitted through the Aedes mosquito, have surfaced. Except for one who lived in a neighbouring road, all the patients had either worked or lived on Clive Street.

Since then, Government agencies have mounted massive operations to eradicate mosquito breeding sites and screen those who had set foot there. National Environment Agency (NEA) officers are also checking surrounding streets as a precautionary measure.

But visitors are still giving the street — named after a British commander whose famous victory in Bengal paved the way for the colonisation of India — a miss.

"Singaporeans are so kiasi (afraid to die). Who would want to come here now? It will be worse when your news article comes out," an irate Mr H Kumar told this reporter as he ordered his workers to stack up the messy pile of cardboards lying just outside his karung guni store. Even the crowds during the morning and evening peak periods have dwindled by half, he lamented.

Business, some shopkeepers said, has fallen by between 40 and 50 per cent in recent days. In contrast, just a few metres away, it's business as usual at adjacent Dunlop Street. Mr Ali, 30, who runs a mobile phone accessory shop, said it's hard to stay away when business appears to be especially good these days.

Down at the corner of Clive Street, a group of Chinese retirees were back at their favourite coffee shop for their regular teatime rendezvous. Its 64-year-old owner, who wished to be known only as Mr Wang, said he had earlier closed the shop because he was so disturbed by the outbreak. He reopened it only after the NEA had fumigated the entire street.

"Seeing the environment officers coming down to inspect almost every day makes me less worried now," said Mr Wang, who now routinely sprays insecticide around his stall just before he closes for the day.

Mr Iqbal, a 45-year-old tailor, went for a blood test on Tuesday. Apart from relying on his trusty can of insecticide, he makes it a point to throw out any stale water and overturn any receptacles before he leaves for home.

For others, the health alert has not affected their routine or plans at all — thanks to a combination of ignorance, nonchalance and faith in bureaucracy.

The handful of tourists checking out the shops at Clive Street said they were unaware of the outbreak. The foreign workers taking a leisurely walk on their day off said they either lived in Clive Street or nearby and it would make little difference whether they shunned the area.

For Madam Thia Lai Bing, who is in her 50s, the street serves as a daily shortcut to Tekka Market. "Once I heard about the outbreak, I told my two sons not to take this road," she said.

Noticing the puzzled look on this reporter, she continued: "I'm old already, so it's okay. My sons are young; they should take care of their health."

Another housewife Madam Masnah, who travels from Tampines to Clive Street once a week to stock up on her groceries, remarked: "As long as the Government is doing something about it, it should be safe."

Rain gutters on most buildings in Little India to be removed
Channel NewsAsia 25 Jan 08;

SINGAPORE: The rain gutters on more than half of the buildings in Little India will be removed.

The National Environment Agency (NEA) has ordered this in a further bid to contain the Chikungunya virus.

Rain gutters are a breeding ground for mosquitoes. More than 1,400 larvae have been found in Little India.

So NEA said that they will be taken out, as long as building structures are not affected.

NEA added that what should be removed are those which are in poor condition or those whose building owners show clear signs that they are unwilling or unable to maintain them in proper condition.

Removing them will help NEA officers who conduct daily routine checks.

Owners who don't comply with the order to remove the gutters may be fined up to S$20,000 or be jailed for not more than three months or both. The sentence and fine will be doubled for subsequent convictions.

Another problem that NEA officers encounter is the pails that foreign workers use to store rain water.

What's more, over 10,000 foreign workers throng Little India on weekends and this makes cleaning up a challenge.

Officials said they will only stop their daily checks when no new cases are found, in 24 days.

That's the number of days needed for mosquitoes to go through two incubation cycles.

At least eight people came down with Chikungunya fever at Clive Street, near Little India in early January and this has caused business to drop by about 10 per cent.

So shopkeepers too are playing their part to maintain cleanliness.

Johnson Kang, a hotel maintenance staff, said: "Normally when we clean all the rooms, we will try to empty whatever pail there is water in it, and every now and then we will check whichever corner. At the same time we have pest control coming once in a while to spray all and clean up all the rooms." -CNA/vm