A series of economic, environmental, and epidemiological factors have combined to present public health officials in Brazil with a very challenging situation this year.
On the economic front, overall financial instability combined with recent currency devaluation has put a significant strain on the ability of the Ministry of Health to conduct vector control and surveillance operations. In addition, a series of government corruption scandals has diminished the willingness of municipalities to partner with private companies.
At the same time, increasing drought conditions have led many residents to install private water storage tanks, which create additional breeding grounds for vector insects, mainly Aedes aegypti.
Taken together, these conditions create an ideal environment for the spread of familiar viruses such as dengue and chikungunya, and the rates of infection have been increasing. But a new viral threat has emerged this year that has public health officials worried.
ZIKA VIRUS—A NEWLY EMERGING THREAT
April 2015 saw the introduction of a new and very dangerous virus toBrazil-the Zika virus. The virus had previously been reported only in Africa and some Pacific islands before it made its appearance in Latin America. A flavivirus like dengue and West Nile, Zika is also carried by Aedes aegypti. In most cases, the virus causes relatively mild symptoms (fever and rash) in infected people who are otherwise healthy. But the Zika virus has been associated with a dangerous birth defect when expectant mothers are infected.
The number of babies born with microcephaly (abnormally small head size, which causes developmental delays) has risen sharply in areas where the Zika virus has been found, particularly in the state of Pernambuco in the northeast. As public health officials have worked diligently in recent months to study the possible connection, the population has grown increasingly concerned.
For more information on the Zika virus, visit www.cdc.gov/zika
DENGUE – THE BATTLE CONTINUES
The dengue virus has a long history in the tropical and subtropical regions of Brazil, dating back to the late 19th century. The first recorded outbreaks occurred in Sáo Palo in 1916 and Rio de Janeiro in 1923. By 1981, it had reached the northern region of Boa Vista. But it was between 2002 and 2011 that dengue established itself as one of the greatest public health challenges in Brazil. The dynamics of viral circulation during this time showed alternating dominance of the DENV1–3 serotypes, with DENV–4 being introduced in the latter half of 2010 and spreading rapidly during the first half of 2011. In 2015, the Health Surveillance Department of the Ministry of Health reported a total of more than 1.5 million cases of dengue through November, representing a 176% increase over the same period in 2014.
CHIKUNGUNYA – ANOTHER RECENT ADVERSARY
Local transmission of the chikungunya virus first occurred in Brazil in 2014, and the virus has been spreading steadily since it established a foothold. In 2015, a total of 9,048 cases were reported through November, 6,985 of which have been confirmed-a 91% increase compared to 2014. The two states with the majority of infections have been Bahia in the northeast and Amapá in the north.
NEW STRATEGIES, NEW APPROACHES
To combat the challenges, engineers from Guarany Machines (a Brazilian manufacturer of application equipment with more than 90 years in business) have been working with product specialists from Valent BioSciences to develop optimal calibrations for wide-area spray applications of VectoBac WG®.
In October 2015, public health companies from Brazil gathered in Itu São Paulo state for two days of technical lectures and hands-on demonstrations of larvicide application strategies and techniques.
The objective is to equip local municipalities with the latest tools and highly detailed technical knowledge to effectively treat hard-to-reach breeding sites for Aedes mosquitoes and help break the transmission cycles of these rapidly spreading viruses.