MUMBAI (Reuters) – At least 55 people have tested positive for the Zika virus in India’s tourist city of Jaipur, up from 22 a week ago, the local health department said on Sunday, raising fears the virus is spreading just ahead of peak tourist season.

Around 280 health officials are doing the rounds of houses in Jaipur in the western state of Rajasthan to detect larvae to control the mosquito-borne virus, the health department said in a statement late on Saturday.

Known for its palaces and museums and deserts close by, Jaipur is a big draw with both foreign and Indian tourists.

This is the third Zika outbreak in India, with the first in the western city of Ahmedabad in January 2017 and the second in the southern state of Tamil Nadu in July 2017 – both of which were “successfully contained”, the government said last week.

First discovered in 1947, the zika virus reached epidemic proportions in Brazil in 2015, when thousands of babies were born with microcephaly, a disorder that causes babies to be born with abnormally small heads and underdeveloped brains.

Of the 55 people found to have tested positive for Zika over the past month in Rajasthan, 38 are no longer showing symptoms of the disease, the department said, adding that officials were conducting fogging to control the mosquito population.

Women in their first trimester of pregnancy are being paid particular attention, said Veenu Gupta, the additional chief health secretary of Rajasthan. Research has shown women are at greatest risk of microcephaly during this period.

There is no vaccine for Zika yet, though Japan’s Takeda Pharmaceutical and some other companies are trying to developing one.

The latest cases come amid a spike in cases of other mosquito-borne diseases in the country, according to the World Health Organization.

The capital New Delhi has reported a rise in cases of dengue fever this year, with 169 reported in the first week of October, taking the total for the year to 650, according to local channel NDTV.

(Reporting by Zeba Siddiqui in Mumbai; Editing by Euan Rocha and Mark Potter)