My husbandf and I are spending 3 days in Anghor Watt the end of February. Then we
go on to Bangkok and SE Asia.

We took Malerone in October/November for our trip to Tanzania...do we need to repeat this processl again?

Where else besides Bangkok are you going in SE Asia? Bangkok is not malarial risk, but almost all of Cambodia, including the area around angkor Wat is.

Here is the page on the cdc site:
wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/malaria-risk-information-and-prophylaxis/cambodia.aspx

As you can see, Malarone is a good option here. Doxycycline is also an option.

We're going on a cruise from Bangkok to Bejing...with stops in HCMC, Danang, HaLong Bay, Japan, Taiwan, Seoul, Shanghai,
HongKong,and an island in Thailand. The only maleria area
is Anghor Watt where we'll be pre-cruise for 3 days...guess I'd better be safe rather than sorry...so we'll get the malerone.

The Scottish National Health Service (part of the UK Health Service) considers the area around Ankor Wat to be a “low” malarial risk and anti-malerials are usually not advised. See http://www.fitfortravel.nhs.uk/desti...ContentHeading or generally see http://www.fitfortravel.scot.nhs.uk/home.aspx (see esp their Malaria page). The UK basically invented tropical medicine, so they can be a good source of info.

For a three day trip and assuming you are staying in an air-conditioned hotel, if you wear mosquito repellent (which you need to wear for things like Dengue Fever in any event) the NHS advises that you should not need medication. Malarial mosquitoes are most active and dawn and dusk so if you are asleep in your air-conditioned hotel at dawn, and take precautions at dusk, this may be sufficient for such a short trip.

Cicerone, I know the map on the Fit for Travel site makes it look like Siem Reap and Angkor are on the border between high risk and low risk, but the text reads "Malaria risk is present throughout the country. Risk is minimal in capital city Phnom Penh, the nearby Mekong river delta and in the rice growing areas around the large inland lake of Tonle Sap."

I'd suggest you consult with a travel med doc about this. In part, what to do depends on your comfort and on whether you are someone who gets bitten by mosquitoes even taking all precautions. But it also depends on any other health issues you have. Sort this out with your physician.

Tonle Sap is where Ankor Wat is located.

No, Tonle Sap is "near" where Angkor is located - it's maybe 45 minutes drive away. A great many of the travel med websites (including the cdc) say specifically that Tonele Sap is not malarial risk but the area around Anhor Temples is malarial risk.

The cdc is US-based and is quite conservative in their recommendations, and I just wanted to point out that there are other views. The World Health Organization’s 2009 Country Risk list indicates that there is only a “limited” risk for Ankor Wat, see http://www.who.int/ith/ITH2009Countrylist.pdf.

Tonle Sap is about 15 miles from Ankor Wat. I agree that even a difference of that few miles can affect whether one area is malarial and another is not; however it is also important to note that if the OP was looking for support for her decision not to take the meds, that it was out there.