HAVANA (Reuters) - Cuban President Raul Castro called on the entire Cuban population to help eradicate the mosquitoes that carry the Zika virus on Monday and ordered 9,000 army troops to help stave off the disease.

Cuba has yet to detect a case of Zika but the outbreak is affecting large parts of Latin America and the Caribbean and is likely to spread to all countries in the Americas except for Canada and Chile, the World Health Organization (WHO) has said.

"It's necessary for every single Cuban to take up this battle as a personal matter," Castro wrote in a national message sounding the alarm over Zika, which is carried by mosquitoes that transmit the virus to humans and which is suspected of causing birth defects after infecting pregnant women.

Cubans should clean up potential environments for the Aedes genus of mosquitoes, said Castro, who also is general of the armed forces.

"The Revolutionary Armed Forces will assign more than 9,000 troops, among them active duty officers and reserve officers ... to the anti-vector and cleanup efforts, with the additional support of 200 officers of the National Revolutionary Police," Castro said.

The ruling Communist Party and the government have adopted an action plan under the direction of the Health Ministry to deal with the Zika that will also help combat the mosquito-borne diseases dengue and chikungunya, Castro said.

One Health Ministry employee, who asked not to be identified as she was not authorized to talk with journalists, said the country's vast network of neighborhood doctors and clinics were watching for Zika symptoms and suspected cases would be quarantined in hospital wards prepared for an eventual outbreak.

"There are no confirmed cases yet but there will be. To date there have been two suspected cases that turned out negative," said the employee, who has real-time access to epidemiological data.

The government, which has fumigated neighborhoods and homes for decades to contain dengue, put doctors on alert for the virus weeks ago and ramped up mosquito eradication efforts.

Military officers could be seen over the weekend, clip boards instead of rifles in hand, directing fumigation in Havana.

The WHO declared the outbreak an international health emergency on Feb. 1, citing a "strongly suspected" relationship between Zika infection in pregnancy and microcephaly, a condition marked by abnormally small head size.

However, much remains unknown about Zika, including whether the virus actually causes microcephaly.

(Reporting by Marc Frank and Daniel Trotta; Editing by Bill Trott)