Brazil is booming. The currency is soaring, people are buying houses and cars at a record pace, global financiers are keen to invest and tourists keep arriving. The country seems poised to acquire official First World status.

But residents of Rio de Janeiro, Brazil’s self-proclaimed “city of wonders,” are worried and angry about a Third World affliction — dengue fever, the tropical disease spreading in epidemic fashion here.

This year, dengue has killed about 90 people in the state of Rio de Janeiro and sickened more than 93,000. Most cases occurred in the city, Brazil’s principal tourist attraction. Dengue has become an annual scourge in a broad swath of tropical Brazil, but this year’s epidemic seems likely to be Rio’s deadliest in recent history.

Rather than blaming the stripe-bellied Aedes aegypti mosquito that spreads the ailment, many cariocas, as Rio residents are known, are lashing out at what they call a confused and belated government response. Critics say officials were slow to fumigate and take other action during the Southern Hemisphere’s summer, when heavy rains created optimum mosquito breeding grounds.

With the number of cases soaring and clinics overwhelmed, officials this month belatedly directed more than 1,000 soldiers to join firefighters, volunteers and others patrolling streets and inspecting tens of thousands of homes in a much-publicized anti-dengue offensive. The teams fumigate and destroy stands of still water where mosquitoes breed.

The dengue epidemic, like the gunbattles pitting police against traffickers in the city’s slums, or favelas, has become a nasty blemish on Rio’s glamorous image. Some accuse the government of trying to keep a lid on dengue to avoid scaring off tourists.

There have been scattered reports of reduced hotel occupancy rates, but no mass cancellations. Indeed, life continues at a hedonistic pace along chic beachfronts such as Copacabana and Ipanema. Few signs warn visitors of the dengue threat at major hotels, the international airport or at approaches to tourist icons such as Corcovado and Pao de Acucar (Sugar Loaf) mountains.

But word is out. The U.S. and other embassies have advised visitors to take precautions, such as wearing long-sleeved shirts and avoiding short pants.

Dengue fever, a viral disease transmitted by infected mosquitoes, is a flulike ailment that causes headaches and elevated temperatures but is usually not fatal. However, physicians worry that a more deadly variant may be spreading here and in neighboring Paraguay, which also faces a dengue crisis.

There is no vaccine for dengue. Treatment usually involves rest and increased intake of fluids.