Chikungunya and Zika Virus Dissemination in the Americas

Different Arboviruses Reflecting the Same Spreading Routes and Poor Vector-Control Policies

Ildefonso Fernández-Salas; Esteban E. Díaz-Gonzá lez; Hugo López-Gatelld; Celia Alpuche-Aranda

Disclosures

Curr Opin Infect Dis. 2016;29(5):467-475. 

In This Article

Abstract and Introduction

Abstract

Purpose of review This review gathers the most recent investigations about chikungunya and zika viruses in America and would help in creating new research approaches.

Recent findings Clinical descriptions of chikungunya fever have been performed in the American outbreak observing that fever, polyarthalgia, myalgia and rash are the most common symptoms in the acute phase, while chronic arthralgia has persisted in 37–90% of small cohorts. The Asian origin of American strains of chikungunya virus (CHIKV) and zika virus (ZIKV) evidences a dissemination route in common and both are being transmitted by Aedes aegypti. Regarding zika fever, the association of congenital malformations with previous ZIKV exposure of pregnant women and potential sexual transmission of ZIKV are the most important discoveries in the New World.

Summary Massive outbreaks of chikungunya fever in 2014 and then followed by zika fever epidemics of lower magnitude in the next year throughout the American continent have their origins in Asia but may have used Pacific Islands as a path of dissemination. Reports of chronic arthralgia have been little described in the continent and more research is needed to measure the economic and health impact in patients who contracted CHIKV before. On the contrary, zika is menacing newborns' health because of its link with congenital microcephaly and sexual health by prolonged presence of viral particles in semen and urine.

Introduction

Although zika virus (ZIKV) is strongly calling attention since the beginning of 2016 due to the World Health Organization international alert, we cannot forget that currently the same Latin-American countries are experiencing more outbreaks and suffering with prolonged joint sequels of past chikungunya fever (CHIKF) epidemics.[1] The overlapping circulation of three arboviruses, dengue virus (DENV) included, is an historical opportunity for the academic field of infectious diseases to analyse and to learn the dynamics of public health epidemiology under this dramatic multipathogen scenario.[2]

From their African original foci and after moving to Asia during several years, both viruses have flourished in naive Latin-American territories impacting with serious incidence rates mostly explained by finding abundant Aedes aegypti mosquito populations in urban and rural settings. Primary health attention centres now have to face patients showing confusing disease symptoms caused by these three arboviruses, that is haemorrhagic manifestations, painful articular swelling with lasting and debilitating damage and potential microcephaly of newborns, along with neurological symptoms such as Guillian-Barre. The hope of dengue vaccine for mass distribution has been diluted because governments are doubtful of its protecting effectiveness taking into account cocirculation of two viral families with differential immune response, that is Flaviviridae and Togaviridae.

The Dengue route, a golden triangle of the Caribbean islands, South and Central America (including Mexico), is a known road seeded with continuous epidemics and built after its reemergence in Latin America during the late 1970; [3] it has remained untouchable since then and has been served now as the chikungunya virus (CHIKV) and ZIKV corridor. It is a geographical pattern matching smoothly with migrant and trade paths; however, these regions also hold perfect Ae. aegypti environments wherein poverty, tropical rainy season, including high moisture and temperature interact to rise abundant mosquito vector populations.[4] A serious concern is the fast speed that these two emergent arboviruses have disseminated through Latin America in a period of almost less than 2 years. Lack of herd immunity in Latin America along with enormous poorly controlled Ae. aegypti living domestically may have undoubtedly triggered important outbreak of CHIKV and ZIKV, but including a rise of Guillain-Barre syndrome cases and congenital malformations associated with the latter.

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