The health news from Brazil is truly remarkable, as the Ministry of Health is advising women in the northeast not to become pregnant at this time because of the emergence of a new disease in the Americas called Zika fever. Historically, Zika fever has been a very rare disease, which until 2007 had caused only a small number of diagnosed cases in Africa and Asia. The Zika virus was native to the forest of Zika in Uganda, where it circulated amongst monkeys. The disease suddenly appeared in 2007 in Micronesia, then spread to French Polynesia in 2013, followed by Easter Island in 2014, before finally arriving in Brazil. The disease causes many of the same symptoms as dengue (high fever, headache, joint and muscle pain, nausea, stomach pain, exhaustion, pain in the back of the eyes, conjunctivitis, a maculopapular rash, and swelling of the legs). This is unsurprising because dengue and the Zika virus are members of the same viral family (flaviviridae), and are both spread by the same species of mosquitoes, particularly Aedes aegypti and Aedes albopictus. There is no treatment or vaccine for Zika fever.
When it first appeared in Bahia, in northeastern Brazil, in April 2013, it was not immediately obvious that this was a new disease. As patients were tested for dengue, however, and the results came back negative, the medical system soon realized that something unusual was happening. While worrying, the disease did not seem disastrous when it appeared in Brazil. People can be infected with Zika fever only once. The symptoms typically last four to seven days, then the patients recovers. In some cases, patients suffer from immunological or neurological disease (Guillain-Barre syndrome) as a result of their infection, but this is atypical. When it appeared, the disease seemed to be less serious than dengue. Very few people have died from it in Brazil. As the epidemic continued, however, doctors began to report a bizarre increase in the number of babies born with a serious birth defect, microcephaly. This disorder is characterized by a reduction in the size of the head of the baby. The rate of this disorder has increased sharply, perhaps ten-fold over the last year. Some doctors at Brazil’s Hospital Oswaldo Cruz are now suggesting that the problem is unrelated to Zika fever, but rather is tied to another emerging infectious disease in the region, Chikungunya.
It is very early in the outbreak to have any reliable information. Nonetheless, the health system is under intense pressure in Brazil, and is seeking to give solid medical advice without causing panic. Those women who are pregnant are taking every possible measure to avoid mosquito bites. The Brazilian media is giving widespread coverage to this issue, particularly in northeastern Brazil, which is perhaps the region most affected. The Brazilian government is now distributing ten million rapid pregnancy tests to states and health systems.
Of course, given that the epidemic has just appeared in the Americas, much remains unknown. What seems striking is the appearance of this new virus at the same time as the number of babies born with serious brain issues has increased. It is still too early, however, for the connection to be proven. Still, many of the women giving birth to babies with this problem also have a history of infection during the first three months of pregnancy, and the World Health Organization is concerned. The Ministry of Health in Brazil has said that it is “highly probable” that there is an association between the two trends. At the current time, people are being told not to panic, and communities are advised to take steps to reduce the number of mosquitoes, which are the main vector (the disease can also be spread through sexual transmission, although this is rare). The disease is now spreading throughout Latin America, and could possibly begin to appear in the border areas of the United States, such as Texas, as well as Puerto Rico, if steps are not taken to control mosquito populations.
As always happens when a new disease appears (see my article on conspiracy theories and the 2009 influenza pandemic) conspiracy theories are now circulating, such as that the disease is caused by the release of transgenic mosquitoes that were intended to fight malaria. To see some examples of these videos (in Portuguese), search Youtube using the terms “farsa” and “Zika.” The explanations for this disaster range from a deliberate attempt at population control, to a terrible accident. Of course, the transgenic mosquitoes were released in the same areas that are now experiencing an outbreak of the Zika fever, because these were the areas suffering from other mosquito-borne diseases, such as dengue and malaria. Health authorities will have counter such conspiracy theories to maintain public trust. In a broader sense, mosquito borne illnesses are becoming an increasing threat to global health, and more research and investment is needed to eradicate the mosquito species that carry dengue, Zika fever and other diseases. Ironically, this will likely include the same use of transgenic mosquitoes that people now point to as having caused the epidemic.
Sadly, Brazil’s northeast also was deeply impacted by another emerging infectious disease that appeared in the 1980s, but this was not one that attacked people, but rather cacao. What was most remarkable about this story was the likelihood that the disease had been introduced deliberately, in a case of bioterrorism. But who was responsible?
Shawn Smallman, Portland State University, December 2015