Costa Rica has witnessed a significant surge in the number of cases of both dengue and chikungunya so far this year, according to the latest statistics by Costa Rica’s Ministry of Health.

The number of cases of dengue had spiked nearly 600 percent while cases of chikungunya had increased nearly seven-fold as of the last week of April compared to the same period last year, according to official statistics.

The country recorded 6,357 cases of dengue between January and April of this year compared to just 981 cases during the same period in 2015, while cases of chikungunya during the same period skyrocketed from 198 last year to 1,372 this year.

Meanwhile, officials expect those numbers to significantly increase with the arrival of the country’s rainy season this month, when the Aedes aegypti mosquito, which spreads both viruses, breeds more fervently.

Authorities are also concerned that the arrival of the rainy season could lead to more significant outbreaks of the Zika virus, which is spread by the same mosquito.

The number of confirmed, indigenous cases of Zika infection in Costa Rica rose to 25 this week after an outbreak in the coastal resort city of Jacó, where health authorities confirmed 11 cases of the virus on Monday.

Health officials continue to urge the public to be vigilant in removing any areas of standing water around their homes, where mosquitos tend to breed.

Experts admit, however that the Aedes aegypti mosquito is hard to contain. It prefers human blood to that of animals, and is a daytime biter.