Yellow Fever Cases Rapidly Increase in Brazil and Health Risks

• 2018 has seen a substantial increase in cases of yellow fever in the states of Rio de Janeiro, Sao Paulo, and Minas Gerais.
• Brazilian health authorities are struggling to deal with the crisis; 154 fatalities were reported between 01 July 2017 and 16 February 2018.
• Yellow fever kills between three and eight per cent of those infected.

Health: The Yellow Fever outbreak in Brazil has reached crisis levels, with a rapid increase in the number of confirmed cases in the states of Rio de Janeiro, Sao Paulo, and Minas Gerais. From 01 July 2017 to 16 February 2018, 464 confirmed cases of yellow fever have been reported in Brazil, including 154 deaths. The outbreak locations are broken down as follows:

Sao Paulo – 181 cases, 53 deaths. 57 per cent of confirmed cases were likely to have been infected in Mairipora Municipality

Minas Gerais – 225 cases, 76 deaths. 45 per cent of the confirmed cases were among residents of Valenca and Teresopolis municipalities.

Rio de Janeiro – 57 cases, 24 deaths. 47 per cent of those infected reside in municipalities located south and southeast of the city of Belo Horizonte. No human cases were reported here during the same period in 2016/2017.

The Federal District (Brasilia) – One fatal case.

The World Health Authority (WHO) has released a concerning assessment. Researchers have been able to find higher than usual levels of infection in wildlife, a higher density of yellow fever in at-risk locations, and in municipalities that were previously not considered at-risk for yellow fever; this third concern is what elevated the current outbreak to a crisis. Unlike the recent zika epidemic, yellow fever is not transmitted by Aedes aegypti, the urban-dwelling mosquito. For this reason, many in urban areas are not vaccinated against the disease.

Two confirmed cases have also occurred in France, the Netherlands, and Argentina, and three in Chile in unvaccinated travellers who had been to infected areas.

What is Yellow Fever?

Yellow fever virus is transmitted to monkeys by forest dwelling mosquitoes such as Haemagogus and Sabethes. Humans who are exposed to these mosquitoes can become infected if they are not vaccinated. Symptoms of yellow fever include fever, headache, jaundice, muscle pain, nausea, vomiting, and fatigue; in most cases, symptoms disappear in three to six days. A small number of patients who contract yellow fever develop severe symptoms and around half of those die within seven to ten days. Yellow fever can be difficult to diagnose in the early stages and can be confused with other diseases such as malaria. The virus is endemic to tropical areas of Africa (where 34 countries are judged to be at risk) and South and Central America (where 13 countries are at risk). The largest outbreaks occur when those infected with yellow fever bring it into highly-populated areas where most people have no immunity to the virus. This allows mosquitoes to transfer the disease from person to person.

What is Being Done?

National authorities have been intensifying vaccination efforts and increasing education surrounding yellow fever. Vaccination campaigns began in 69 municipalities in Sao Paulo and Rio de Janeiro States in late January 2018. The most recent figures suggest that 4.3 million people have vaccinated out of a planned total of 20 million; this represents only 21 per cent (12.1 per cent in Rio de Janeiro and 29.6 per cent in Sao Paulo). The WHO suggests that the low vaccination rates show that there is still a significant number of at-risk people, meaning more must be done, especially to reach high-risk and hard-to-reach groups.