Brazil: Reported cases of dengue, Zika, and chikungunya down in 2017

Event

Rates of dengue fever, the Zika virus, and chikungunya are down in Brazil through most of 2017, compared to the same period in 2016. Through November 11, the number of suspected cases of dengue fever reported in 2017 was 239,076 - 83.7 percent lower than over the same period in 2016, according to the Brazilian Ministry of Health. The number of reported cases of the Zika virus also precipitously declined in 2017: 16,970 cases have been reported through mid-November 2017 - a 92.1 percent drop from the same period in 2016. A 32 percent drop in suspected cases of chikungunya was reported in 2017 through mid-November compared to the same period in 2016 (217,631 reported in 2016 versus 184,458 reported in 2017).

Health officials attributed the decreased incidence of the three mosquito-borne diseases to both government prevention campaigns and improved personal prevention measures taken by Brazilian citizens. Despite the improved prevention measures against the illnesses, the risk of an incipient epidemic remains in many municipalities, according to the country's Aedes aegypti Infestation Index.

Context

Symptoms of dengue fever include fever, headache, muscle and joint pain, fatigue, nausea, and rashes. Dengue Hemorrhagic Fever (DHF) is a potentially deadly complication that is characterized by high fever, the enlargement of the liver, and hemorrhaging.

Although the Zika virus is usually relatively benign, links between it and severe birth defects as well as the potentially fatal neurological disorder Guillain-Barre syndrome (GBS) have been established. The virus is asymptomatic in approximately 80 percent of cases; when symptoms do occur, they generally appear two to seven days after infection, and include fever, headache (behind the eyes), conjunctivitis, rashes, vomiting, and muscle and joint pain. The disease can also be transmitted via sexual intercourse.

Symptoms of chikungunya include fever, headache, joint and muscle ache, fatigue, nausea, diarrhea, and rashes. The virus is infrequently fatal but potentially debilitating joint pain can last for weeks, even months, after the initial recovery.

Advice

Individuals present in Brazil are advised to monitor developments to the situation and take measures to protect themselves from mosquito bites (e.g. by wearing covering clothing, using insect repellent, and sleeping in a screened-in or air-conditioned room). Additionally, eliminate possible mosquito breeding grounds (small pockets of fresh water, such as rain water that has collected in cans, bottles, tires, flower pots, clogged gutters, etc.).​