Examining Brazil's Zika virus up close

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Michele Schifino is a Brazilian journalist who for the last 13 years has been engaged in social causes. The views stated in this report are her own and do not represent the position of the company that she currently works for.




Zika & babies’ anomalies in Brazil: mosquitoes or human rights?

The Zika virus was first identified in 1947, during a routine research on yellow fever in Uganda. It wasn’t until 2007 that the current pandemic amongst humans began on the island of Yap, Micronesia, with 185 positive cases from a population of just 11,250 people. Between 2013 and 2014 thousands of cases in French Polynesia, Easter Islands, The Cook Islands and New Caledonia were reported to the WHO. However it wasn’t until the Brazilian epidemic of 2015 that the Zika virus rose to global prominence. The Brazilian Ministry of Health recently reported 1.6 million suspected cases of Dengue occurred during 2015, with at least 497,593 of these cases potentially connected to the Zika virus. Although at the outbreak of the epidemic in 2015 there were no examinations available to confirm positive cases for the Zika virus. In addition to this, many of those infected didn’t contact the Brazilian health services, with only 20% of positive cases having high symptoms.

Like the Dengue virus and Chikungunya, Zika is also transmitted by the mosquito Aedes aegypti. Due to a lack of knowledge of the virus it was considered a simple pathology. This was because it could be treated 2-7 days after manifestation of high fever, which is commonly followed by skin rashes, joints and ocular pain. If it was not for the thousands of anomalies in babies infected by the Zika virus during pregnancy, it may still have been treated as a simple pathology. The mosquito has become notorious not only with the Brazilian Health Services, but also with other Latin American countries as Zika cases are reported there.

But is Zika really causing microcephaly in babies?

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The relation between Zika and microcephaly

There has been an alarming growth in the number of microcephaly cases since October 2015 in seven states of Northeast, especially in Pernambuco. As a result, in November 2015, the Ministry of Health declared a state of emergency in Brazil. In the following two months, the number of confirmed cases of microcephaly doubled, compared to the total number of confirmed cases throughout the year 2014. Following this sharp increase in the number of cases, the authorities began to relate the Zika virus to the outbreak of babies with congenital abnormalities – other causes can be syphilis, toxoplasmosis, rubella, cytomegalovirus, herpes and infectious agents.

Adriana Melo, the Brazilian doctor who was the pioneer on this issue, identified the association of the same factors in the cases of fetuses with microcephaly: Firstly infections during the first trimester of pregnancy had similar symptoms of the Zika Virus, which coincided at the same time when the epidemic started in Northeastern Brazil. Secondly, calcifications in the brain of the fetuses, which relates to a congenital infection disease. Thirdly, the Zika virus genome was detected in the amniotic fluid of pregnant women.

Following two months of self-funded examinations, Adriana was able to prove the congenital infection of the fetus by the virus and brought it to the attention of fellow doctors, the Ministry of Health and the WHO. But is this linear model of cause-and-effect the best way to study and prevent these malformations in babies?

The most recent Ministry of Health report regarding the occurrence of microcephaly launched on the 12th of February, shows that only 41 of 462 confirmed cases of congenital anomalies were demonstrably connected to the Zika virus. While 765 potential cases were discarded due to no relation with congenital infections, 3852 other reported cases are still currently being investigated. 

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Firstly, these numbers show that Zika is present in less than 10% of confirmed congenital microcephaly cases. The veracity of the results and the data baseline are potentially unreliable, due to the previously unknown nature of the virus. Due to a lack of knowledge of the virus and the fact the symptoms were similar to Dengue and Chikungunya, potential Zika cases were not recorded. It should also be noted that Zika was considered only a factor rather than the main cause for anomalies in babies. This is mainly because outbreaks of microcephaly were never reported as a consequence of the Zika virus, even in countries which had recorded a high number of cases of the virus.

The publication of an article in the New York Times on Zika’s epidemic in Colombia calls into question the credibility of its association with microcephaly. According to the Colombia's President, Juan Manuel Santos, there is no evidence of anomalies in babies in the country, although 3,177 pregnant women have been diagnosed with the Zika virus since October. It is estimated that 25,000 people in Colombia were infected with the Zika virus with no microcephaly cases being reported. Nevertheless, three people died due to paralysis caused by Guillain-Barre syndrome, which is also associated with the Zika virus.

It’s important to take into account that Brazilian studies indicate the congenital infection by Zika happens mainly during the first trimester of pregnancy – so it’s too early to disassociate Zika from microcephaly using Colombia as an example. The outbreak of the virus started in Colombia four months ago and women who have been infected within the first three months of pregnancy can only be examined for identification of anomalies when the woman reaches 32 weeks of pregnancy. Only then can the studies determine association (or disassociation) between Zika and microcephaly. 

Behind the scenes: the human right to water and sanitation

If Colombia keeps its population free from microcephaly cases in the following months, it will then be possible to investigate the spatial distribution and the environmental aspects that make this a localised crisis for Northeast countries in Brazil. Doctors and researchers have stated that a lack of basic sanitation, poor quality of water and the use of chemical mechanisms to repel the mosquito are the three biggest obstacles to reducing the number of Zika cases. An example of this being the majority of people already affected by microcephaly come from poor communities with houses supplied by reservoir water. From the second half of 2014, the water was chemically modified by Larvicide to avoid – guess what? – the mosquito.

This chemical model for vector control was highlighted in a technical note from the Brazilian Association of Collective Health. They are relating microcephaly cases with many factors, such as the use of Pyroproxyfen, the larvicide applied directly by the Brazilian Ministry of Health on drinking-water reservoirs (tank storages) over the last 18 months. This poison, recommended by the WHO, is a growth inhibitor of mosquito larvae, which alters the process larva-pupa-adult, thus generating malformations and inhibiting the development of adult insect characteristics, which means that it acts by endocrine disruption and that is teratogenic. The product is being used in Pernambuco, the most affected state regarding microcephaly.

For now, there is no evidence that to validate these theories – but after these recent announcements, one Brazilian state has already prohibited the use of Pyroproxyfen in drinking water for precaution. The Ministry of Health has immediately published a note confirming that there are no scientific studies relating the pesticide with brain damages in humans.

While babies are being condemned to an unhealthy life, the Government fails in trying to find a linear cause for microcephaly, instead of adopting a holistic approach that considers the human right for water and sanitation.  It is impossible to ignore the comparison with earlier outbreaks in other regions of the world, as well as the environmental aspects once there’s a restricted spatial and social distribution of the microcephaly in Brazil. So maybe the question is not if the Zika is causing microcephaly, but why is this anomaly highly concentrated in the Northeast of Brazil, when the entire country is being affected by the mosquitoes?

Notifications of Microcephaly: spatial distribution since 2015

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Further information:

WHO: www.who.org

- Zika Virus Q&A
- Zika Virus Fact Sheet
- Microcephaly Key Facts
- Microcephaly Q&A
- Guillain-Barré Syndrome Fact Sheet