Zika outbreak: are we affected?

The Zika virus outbreak in Brazil has been associated with a significant rise in the number of babies born with microcephaly and neurological disorders, and has been declared a "Global Emergency" by the World Health Organization.

Let’s talk about Zika!

Zika Virus outside Africa.  Zika virus infection presents with acute onset of fever, maculopapular rash, arthralgia and conjunctivitis.  It is an Aedes mosquito-borne flavivirus  that was first discovered in 1947 in the Zika Forest of Uganda, infecting a rhesus monkey. Its serum was inoculated into mice.  Zika virus was isolated from mouse brains.  Zika was isolated from humans in Nigeria during studies conducted in 1968 and during 1971-1975.  From 1951 through 1981, serologic evidence of human ZIKV infection was reported from other African countries such as Uganda, Tanzania, Egypt, Central African Republic, Sierra Leone and Gabon, and in parts of Asia including India, Malaysia, Philippines, Thailand, Vietnam and Indonesia.

Zika Virus Infection in the Philippines.  In an active surveillance for acute febrile illness initiated in Cebu City, Philippines, in 2012, there was a report of a 15-year old boy who reported a subjective fever.  ZIKV RNA was detected in his serum sample.  The boy recovered fully by 3 weeks. Most infections are asymptomatic, and symptomatic disease generally is mild.

Between 2012-2014, the Pacific experienced a high burden of mosquito-borne disease due to concurrent epidemics of dengue, chikungunya and Zika virus infections.  Data from the French Polynesia documented a concomitant epidemic of 73 cases of Guillain-Barre syndrome and other neurologic conditions.  

Zika Virus Transmission from French Polynesia to Brazil.  There are some theories on the introduction of ZIKV to Brazil from the French Polynesia: during a World Cup soccer competition in 2014, or during the Va'a World Spirit Championship canoe race in Rio de Janeiro in 2014.   In May 2015, Zika spreads through local transmission in Brazil.  Following the spread of the Zika virus in Brazil, there has been a marked reported increase in the number of infants born with microcephaly. Until more is known, pregnant women should consider postponing travel to any area with ongoing Zika virus transmission.  Health authorities recommend that pregnant women take meticulous precautions to avoid mosquito bites and even to delay pregnancy.

LINK BETWEEN ZIKA AND MICROCEPHALY

Carlos Brito (2015) explained it well in his article Zika Virus:  New Chapter in the History of Medicine:

The increase in cases of microcephaly could be associated to Zika virus infection based on the following clinical-epidemiological aspectsand in the different diagnosis:

• the outbreak of many cases in a short space of time, occuring simultaneously in different cities and states characterizes a disease with high attack rates and rapid dispersion, a phenomenon associated with disease transmitted by arthropods;
• besides microcephaly, image exams presented some common characteristics such as: periventricular and cortical microcalcifications, vernix cerebellar hypoplasia and in some cases lisencephaly compatible with the pattern of congenital infections;
• diseases associated to TORCH, because of the transmission pattern, are not associated with large outbreaks; 
• the investigation in prenatal and perinatal were negative for TORCH infections;
• most of the mothers (70%) reported compatible features of Zika disease in the first trimester of pregnancy, the period in which the Zika V outbreak occured in the region.

Identification of zika virus in the amniotic fluid samples, brain tissue and placental tissues strengthen the link between Zika virus and microcephaly.

Alerts from the Brazil Ministry of Health, European Centre for Disease Prevention and Control, and the CDC concerning the possible association of microcephaly with the recent outbreak of Zika virus infection.  Several reports were posted as MMWR Early Release on the MMWR website, including interim guidelines on pregnant women, on infants with congential Zika virus infection, on healthcare providers caring for pregnant women and women of reproductive age, on prevention of sexual transmission.

Preventive measures would involve prevention of transmission.  Zika virus infection has been known to be transmitted through mosquito bites, through sexual transmission (proven by cases in Tahiti and USA) and through blood transfusion of blood infected with the Zika virus.

Let's talk about Zika now!  ...and do something about it!