A technician demonstrates a laboratory instrument used to test the Zika virus at the Bamrasnaradura Infectious Diseases Institute in Nonthaburi province. Health officials have just found two more patients in Chiang Mai province. (Photo by Pattarapong Chatpattarasill)

Two more women, aged 18 and 74, have been confirmed infected by the Zika virus in San Sai district, Chiang Mai, where seven other people recently diagnosed with the infection in the district have fully recovered.

Chiang Mai governor Pawin Chamniprasart said on Friday that an 18-year-old university student fell sick last Saturday, saw a doctor on Tuesday and was diagnosed with the disease on Thursday.

The elderly woman fell sick on Wednesday and her infection was also confirmed on Thursday. Both women live in tambon Nong Han of San Sai district, where previous patients were found, Mr Pawin said.

There have been nine Zika patients diagnosed in the northern province in the past week. Seven have recovered.

Nearly 3,000 people have also been recorded with dengue haemorrhagic fever in Chiang Mai this year.  A nine-year-old girl recently died of it in Hang Dong district, raising the death toll to three.

The striped mosquitoes, Aedes aegypti, are the carriers of both Zika and haemorrhagic fever. The two diseases are related.