Can pregnant women pass the dengue virus to their unborn children?

Yes, it is possible, said Associate Professor Leo Yee Sin, the clinical director of the Communicable Disease Centre - though no case has been reported in Singapore so far. A mother's placenta does not filter the dengue virus from crossing over to the foetus.

The survival of the foetus depends on the clinical condition of its mother. Although the foetus does not die from the virus itself, it can be harmed if its mother develops a more severe case of dengue, or goes into dengue shock syndrome.

Dr Jenny Low, associate consultant at the department of internal medicine at the Singapore General Hospital, said there is no known treatment so far.

Can you get dengue from any other vector such as rats?

No.

Can dengue be passed through blood transfusion?

Technically, it is possible for dengue to be transmitted through blood transfusions, said Prof Leo, though again there is no known case of such a thing happening in Singapore. But in October 2003, two patients died of multi-organ failure when they received dengue-infected kidneys through a transplant. Doctors were not aware at the time that the donor, who died of severe head injuries, had the disease.

Does papaya juice help to increase blood platelet count?

E-mails were circulated in November last year with testimonies from patients who had increased their blood platelet count by drinking raw papaya leaf juice. The body contains two types of blood cells: red and white. White blood cells help to fight off illnesses.

Dengue fever decreases the amount of white blood cells, exposing the patient to illness. Papaya juice is believed to increase the number of white blood cells in the body. There is no scientific proof of this, however. Prof Leo said she does not know of any proven effect from consuming papaya juice.

When are dengue patients admitted at hospitals?

The Ministry of Health's criteria for admitting patients with dengue are when their blood platelet count drops to 80,000 and below, which puts them in danger of haemorrhaging. The platelet count tends to drop when the patient's fever starts to subside. A normal person's average count ranges from 150,000 to 450,000.

Can dengue be treated at home?

As long as the blood platelet count is above the critical number, it is okay for patients to remain at home. But, they should go for check-ups every day at a clinic to check their blood count.

Can dengue be spread to pets?

Pets may get bitten by an Aedes mosquito looking for an available bloodmeal, though Aedes prefer humans. If the mosquito is infected, then virus transmission could occur. However, animals do not fall sick with dengue, said DrChristina Liew, senior research scientist at the Environmental Health Institute.

What are the complications caused by dengue or dengue haemorrhagic fever (DHF)?

Ophthalmologists at Tan Tock Seng Hospital (TTSH) have found some dengue patients to develop eye problems, causing blurred vision during day six or seven of getting dengue fever.

Between mid-2004 to 2005, TTSH saw about 100 cases of eye complications related to dengue infections. This year, the hospital has seen about 10 to 20 such cases. Doctors do not yet know what the relation is between eye complications and dengue, but most disappear on their own within three months, said Dr Stephen Teoh. In extreme cases, a patient will not recover full vision.

Dengue fever and DHF also cause inflammation of the liver in most patients.

Can one get all four strains of the virus? Does that make you immune to dengue?

Yes. There is no known research from Singapore so far, but evidence from surveys done in other countries show there are individuals with all four serotype infections. How many there are in Singapore is not known as doctors do not screen for all four serotypes in a clinical setting. These individuals are in theory immune to dengue after experiencing all four.

What are some advancements in diagnosing dengue?

There is no on-the-spot test available in clinics at the moment. Blood samples are sent to laboratories to test for two things. First, to detect the dengue virus in the blood stream and second, to detect antibodies produced in patients against the dengue virus.

Prof Leo hopes that research will be done to develop an on-the-spot test to detect the virus in patients.

What should I be careful of after recovering from dengue?

Allow the body to recover fully. Post-viral asthenia, or weakness, is fairly common after dengue fever. Patients are recommended to continue being vigilant and to keep the environment clean to prevent re-infection.

Is dengue infectious? Are doctors and nurses dealing with dengue patients safe?

Dengue does not transmit from human to human. It needs a vector, in this case the Aedes mosquito, to spread the disease. Hence, doctors and nurses dealing with patients are safe.