A decade ago, Dengue Fever guitarist Zac Holtzman, fresh off a 10-year stint with the San Francisco band Dieselhed who recorded two LPs for Bong Load Records in 1999 and 2000, started a new band, a Cambodian-American rock hybrid inspired by cassettes he had of popular Khmer musicians.

During theVietnam War, Holtzman says by phone from his home in Echo Park, Calif., American troops dropped rock music on an unsuspecting Cambodia, forever changing the musical landscape of the diminutive country at the same time bombs altered the Southeast Asian countryside. “In addition to bombs, we dropped Hendrix, Funkadelic andJames Brown,” explains Holtzman. “It totally changed their music.”

The brutal modern history of Cambodia, which is bordered by Vietnam, Laos,Thailand and the Gulf of Thailand and whose population overwhelmingly comprises the Khmer ethnic group, is well known. The Khmer monarchy became a French protectorate in 1863, at the end of a two-decade-long flowering of the arts under King Ang Duong. Nearly a century later, in 1953,PrinceNorodom Sihanouk proclaimed Cambodia's independence, abdicated his throne, and became Head of State. On March 18, 1970, a military coup overthrew Sihanouk's government, and the Khmer Republic was born. Around that time, theVietnam War began spilling over into Cambodia.

An entire generation of Cambodians was largely wiped out after the Khmer Rouge assumed control on April 17, 1975, and, in the next four years, killed two million Cambodians, including thousands of respected intellectuals and artists. (The lost musicians and their music is the subject of Don't Think I've Forgotten: Cambodia's LostRock and Roll, adocumentary in production but already showing in Singapore.) The reign of terror ended in 1979, but a national constitution, along with a coalition government and a reinstated monarchy, wouldn't arrive until 1993.

To Cambodians, DF is a reflection, late '60s Cambodian pop in a mirror, informed by three subsequent decades of development in Western pop, back to its own shores, a sort of nonviolent, considerably sophisticated musical invasion. With a well-placed musical gesture, a foreign or familiar melodic mode, chord progression or beat, DF jumps between Western and Eastern territory, between the retro garage/surf rock of “Cement Slippers,” the second track on their latest Fantasy recording Cannibal Courtship, and the Afrobeat-heavy “Only A Friend,” or from the French pop of Stereolab on the title track, with harmonies by the Living Sisters, to its own punishing, mid-tempo chorus. It's like flipping a switch.

“I don't think we write them that way,” says Holtzman. “We don't plan out which modes we are going to use. But sometimes we just end up on those modes. A lot of the droning stuff too: When we play that rehearsal [lead singer Chhom] Nimol just starts singing along. If I just play something she'll just start singing. There are these different genres of Cambodian music that have dances that go along with them.” Nimol, Holtzman says, hears something familiar, and dives in.

Dengue Fever filmed its first band trip to Cambodia in 2005, a homecoming for Nimol, who hadn't been home in five years. “We wanted to capture that, and we wanted to film and record Cambodians' reactions to our playing their style of music,” Holtzman says. “Before we got there there were rumors that Nimol had started playing music with a Hollywood band and that they didn't know what to expect. They thought she'd becomeCeline Dion.” When Cambodians hear Dengue Fever they often “circle dance,” a slow, tai chi-like move, reminiscent of traditional Khmer social courtship dances — roam vung, roam kbach, saravine and liam Leav. The way Holtzman tells it, it's sort of comical for those used to Western rock audiences.

“The dance floor will be completely empty,” Holtzman says. “Then the band will start playing the song. Everyone takes one more bite of their food or another drink and they all go out on the dance floor. Then they'll go back to their food. It's like they are pacing themselves for the whole night.”

Dengue Fever released Electric Cambodia: 14 Rare Gems From Cambodia's Past, a compilation of songs by the original artists, in 2010. They give the proceeds to Cambodian Living Arts, an organization that helps underprivileged kids to sing and to dance and to learn from traditional master musicians. Cannibal Courtship, DF's fifth full-length album of original songs, Holtzman says, is “a game of tag, artistic tag of inspiration. That's how we came up with the name. It's us [the U.S. and Cambodia] being inspired by each other.” A gold double-necked Fender Jazzmaster/electric chapey — The Mastodong, as it's known — graces the cover. Nimol assumes the posture of a Khmer dancer. “We are dating each other's cultures and we are feeding off of each other,” Holtzman says.

A week after their show in Northampton, DF heads to England to headline the Meltdown Festival, curated by the Kinks'Ray Davies, and then at theGlastonbury Festival. In November, they'll return to Cambodia to play a show attheU.S. Embassy to celebrate 30 years of the two countries getting along. “It's great to be arock and roll ambassador,” Holtzman says, and he thinks of his band as part of the current transformation of world music.

“It was a bad word, at least for us,” Holtzman says. “It used to mean Guatemalan pants.”

Write to mhamad@hartfordadvocate.com. Follow me on Twitter at @MikeHamad.

Dengue Fever With the Eternals. June 6, 7 p.m., $12-$14,Iron Horse Music Hall, 20 Center St., Northampton, (413) 586-8686, iheg.com