Zika virus possible came to Brazil through Central America, says Fiocruz PE study
Unlike previously thought, the Zika virus did not entered the country during the 2014 World Cup, or during the Canoeing World Championships, held in August 2014 in Rio de Janeiro12/09/2018
A study published recently in the International Journal of Genomics entitled Revisiting Key Entry Routes of Human Epidemic Arboviruses into the Mainland Americas through Large-Scale Phylogenomics filled a gap in the literature about the Zika virus by tracing the route of arrival in Brazil. According to researcher Lindomar Pena, one of the authors of the research, the main importance of the study is that it identifies Central America and the Caribbean as important entry routes for Zika and other arboviruses, such as dengue and chikungunya in Brazil. This is an important information to support health managers as to monitoring and early detection of possible arbovirus imported from that region to Brazil, especially in ports, airports and border areas with other countries. Dr. Gabriel Wallau, who also participated in the research, adds that these regions, along with ports and airports, should be prioritized for viral monitoring both for people and vectors that can be carried through different means of transport. A well-mounted epidemiological surveillance could quickly detect new passing pathogen and then guide decision-making about the containment and control measures to prevent the new pathogen to spread, he says.
The virus entry route
Dr. Pena explains that, unlike what was thought, Zika virus did not enter Brazil during the 2014 World Cup, nor during the World Canoe Championship held in August 2014 in Rio de Janeiro. Still according to Dr. Sorry, the results indicate that the virus arrived in the country at the end of 2013, coming from Central America and the Caribbean. This way, the Zika virus followed the same route from the Asian genotype of chikungunya and dengue viruses: from Asia to Oceania, emerging in Central America and the Caribbean Islands, and finally coming to South America. We dont know how it was imported to Brazil and maybe we will never know, because the first patient to come to Brazil before the beginning of the epidemic has never been identified. However, as there is a flow of illegal immigrants from Haiti and Brazilian military traveled in a peace mission to that country until 2017, it becomes a possible way for Zika virus to reach Brazil , adds the researcher while observing what other possibilities cannot be discarded.
Dr. Wallau stresses the importance of clarifying that the path traveled by the zika, dengue and chikungunya virus would have been the same, at least for the four Dengue serotypes, the Chikungunya Asian genotype and the Asian Zika virus genotype, since there is another lineage of the Chikungunya virus circulating in Brazil, from Africa. According to him, another important point to note is that this path was taken at different times by different serotypes of Dengue and other arboviruses. The relation shows that the flow of people between Central and South America is intense, allowing the rapid spread of these viruses between these regions, he says.
The research and the next steps
Dr. Pena tells the search idea emerged from the detection and sequencing for the first time the Zika virus in the State of Pernambuco in 2016. By sequencing the virus circulating in Pernambuco, we detected that it was the Asian strain, not the African strain. A very important question to be answered was the origin of the virus and what was its route to Brazil. To answer this question, we have analyzed all genomic sequences of the Zika virus isolated from humans available at GenBank, a global gene bank, using state-of-the-art computational tools. He details that now it is necessary to monitor the evolution of the virus in the inter-epidemic period, in order to detect its mutations for natural evolution and to understand the meaning of these changes regarding virulence, transmissibility, antiviral resistance and the ability to escape the immune system. However, these studies are severely threatened by brutal budget cutbacks the Government has struck in the Brazilian research, he mourns.
Besides Dr. Lindomar Pena and Dr. Gabriel Wallau, the study counted with the participation of researchers Tulio Campos and Antonio Rezende, from Pernambuco Fiocruz, and Alain Kohl, a collaborator from the University of Glasgow.
Brazil may again suffer from epidemics of Zika and Chikungunya
According to Dr. Pena, we may have new outbreaks of Chikungunya, dengue Zika, or even other arboviruses. According to him, the precariousness of basic sanitation in Brazil favors the genesis and spread of arboviral diseases, against which we have no antivirals or vaccines available (except for dengue, against which there is a vaccine approved by Anvisa, but is not yet widely used). To prevent such diseases, he is categorical in stating that the best strategy is the investment in basic sanitation infrastructure, which includes drinking water supply, rainwater management, sewage collection and treatment, urban cleaning, solid waste and the control of the vectors of these diseases, such as mosquitoes from the genus Aedes and Culex. The arboviral diseases are those whose incidence is strongly influenced by environmental conditions. To control them, it is necessary to invest in health education, sanitation infrastructure and urbanization policies of cities in a sustainable way. Unfortunately, these actions do not reflect in election votes, generating little interest of politicians in implementing them, he concludes.
Dr. Wallau admits the possibility of Zika virus causing smaller outbreaks again as it mutates or reaches populations not yet infected. This analysis is based on the experience with the Dengue virus, which settled in Brazil for many years, but still causes annual outbreaks in different regions. The data indicate that it is unlikely that we will have another world-wide epidemic like 2015/2016, but also shows that the virus continues to circulate, so smaller outbreaks should happen over time. Further research is needed to monitor the evolution of this virus and detect where these new outbreaks may occur, he argues.
Despite the current data shows that the number of people infected by Zika in Brazil has dramatically decreased, which is expected since most of the population has been infected and developed antibodies against the virus, patients infected with the virus are still reported, showing that Zika still is circulating and probably will remain circulating in the country.…