ZIKA VIRUS WHAT IS IT? WHERE DID IT COME FROM? HOW DID IT GET HERE? [PDF]

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L I L I A N A V . R I O S , M . D . I N F E C T I O U S D I S E A S E C O N S U L T A N T S

ZIKA VIRUS

WHAT IS IT? WHERE DID IT COME FROM? HOW DID IT GET HERE?

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EPIDEMIOLOGY

A single stranded RNA

virus

Genus: Flavivirus
Classified amongst

better known : Dengue Virus (DEN), West Nile Virus (WNV), Yellow Fever (YF) Virus, Japanese encephalitis (JE) virus

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EPIDEMIOLOGY

Vector: spread by the

bite of an infected female Aedes mosquito.

Distinctive black &

white markings

Usually bites during the

daytime

Breeds in standing

water, particularly manmade containers [1]

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ZIKA VIRUS DISEASE

Presents similarly to Dengue

and Chikungunya

Asymptomatic infection 80%
Or a mild febrile illness 20%
Symptoms include:
Fever
Rash
Joint pains
Red eyes
In less than 1%, neurologic

syndromes can occur

Guillain-Barré syndrome
Microcephaly In the

developing fetus[2]

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THE ORIGIN OF THE VIRUS

Discovered: 1947
As scientists worked on

YF transmission.

A. J. Haddow, MD
Aedes Africanis
Rhesus monkey
Officially named

in1948, after the Zika Forest in Uganda.[3]

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ZIKA VIRUS : AN EMERGING VIRUS

Between 1947 and 2006
Only 14 reports of human cases documented
First native case in 1954
A 10 yr old girl in Nigeria who had a mild febrile

illness and recovered completely.[4]

First experimental infection in a human volunteer

in 1956

Experienced a mild febrile illness and recovered

completely.[5]

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ZIKA VIRUS : AN EMERGING VIRUS

In 2007
An outbreak occurred on the island of Yap

(Federal States of Micronesia).

49 confirmed and 59 probable cases of Zika

virus disease

An estimated 73% of Yap residents >3 years of

age had been recently infected with Zika virus

Aedes hensilli was the mosquito identified[6]

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ZIKA VIRUS : AN EMERGING VIRUS

In 2013
An epidemic of Zika virus emerged in French

Polynesia where Dengue is endemic.

A larger scale of people were exposed at an

estimated 28,000 cases; approximately 11% of the population.

And yet the true incidence of exposure was

likely under reported as infection is most commonly asymptomatic.

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ZIKA VIRUS : AN EMERGING VIRUS

In contrast to YAP, serious effects become obvious

when the virus affects a lot of people in French Polynesia.

Correlations to the more uncommon clinical

neurologic manifestations of Guillain-Barré syndrome are unmasked and first associated to Zika virus. [7]

Smaller outbreaks then followed from French

Polynesia to the cook islands, Easter Island and the Solomon Islands.[8]

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ZIKA VIRUS : AN EMERGING VIRUS

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RACE TO THE AMERICAS

Northeastern Brazil, 2015
The Aedes mosquito is endemic here as is Dengue

fever.

However, up to 60,000 cases with non-Dengue and

non-Chikungunya began accumulating.

Thus, scientists take note at the Oswaldo Cruz

foundation and began investigating.

On June 2015, the first domestic transmission of Zika

virus was confirmed and documented in Brazil.

They used phylogenetic analysis and traced the virus to the

Asian clade of Zika virus

confirmed by PCR DNA sequencing[9]

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RACE TO THE AMERICAS

The precise means by which Zika Virus was

introduced to the Western Hemisphere is unknown.

Brazil reported 1.5 million cases, and more than

4,000 suspected cases of microcephaly in babies.

The predominant incidence however was in the poorer

northeast.

Zika rapidly spread throughout Latin America and

the Caribbean, such that within 1 year most countries in the region reported local transmission.

[10]

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HOW IT GOT TO THE AMERICAS

Postulates from Journal of Virology and Scientific

American:

The viremic traveler from the French Polynesia via:
FIFA Confederations Cup, which was held in

Brazil from 15 June to 30 June 2013

World cup soccer competition July 2014

(what an upset!)

Va’a world sprint Championship canoe race in

Rio de Janeiro Brazil in August 2014

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THE ZIKAVIRUS, CLASS DIVIDE, AND CLIMATE CLASH

In our current scholarly articles; Asian Pac J Trop

Biomed and New England Journal of Medicine:

Emergence of the world as a global village.
Climate change
summer heat waves, drought, and heavy rains with flash

floods.

Human factors
many inhabitants in large cities
Lack of : electricity, running water, garbage collection,

sewers and drains for rain.

Inadequate health service
Dev of vector resistance to insecticides[11 -12]

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AN ESTABLISHED GLOBAL THREAT

On Nov 1, 2015 the Brazil Ministry of Health declared a

public health emergency as the number of cases of microcephaly continued to increase.

On February 1, 2016 The World Health Organization

(WHO) declared the cluster of microcephaly cases and

ther neurological disorders a health emergency.
On February 8, 2016, the Centers for Disease Control

(CDC) elevated its response efforts to a Level 1 activation.

The WHO launched the global Strategic Response Framework

to encompass surveillance, response activities and research.

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HOW IT GOT TO THE US*? FLORIDA DEPT. OF HEALTH

Local transmission via domestic mosquito vector has

been reported in Puerto Rico (*US territory), but not elsewhere in the United States.

Cases of Zika fever have been reported in travelers

returning to the United States.

secondary transmission is possible via sex.

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CDC UPDATE JANUARY 1, 2015 – JUNE 1, 2016.

US States

Travel-associated cases reported: 618
Florida cases – 128
Locally acquired vector-borne cases reported: 0
Total: 618
Sexually transmitted: 11
Guillain-Barré syndrome: 1

US Territories

Travel-associated cases reported: 4
Locally acquired cases reported: 1,110
Total: 1,114
Guillain-Barré syndrome: 8

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THE ZIKA VIRUS TIME LINE

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R E P O R T S 6 0 C O U N T R I E S A N D T E R R I T O R I E S R E P O R T C O N T I N U I N G M O S Q U I T O - B O R N E T R A N S M I S S I O N .

AS OF 1 JUNE 2016, THE WHO

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INFECTIOUS DISEASE CONSULTANTS

We specialize in

Infectious Diseases & Travel Health.

For an appointment

call: 407.830.5577

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CITATIONS

1. http://www.floridahealth.gov/diseases-and-conditions/zika-virus/index.html 2. CDC.gov 3. Zika Virus (I). Isolations and serological specificity. G.W. A. Dick, S.F. Kitchen,

A. J. Haddow. Trans R Soc Trop Med Hyg (1952)46 (5): 509-

520.doi: 10.1016/0035-9203(52)90042-4. 4. MacNamara, F.N. (March 1954). "Zika virus: a report on three cases of human infection during an epidemic of jaundice in Nigeria.". Transactions

f the Royal Society of Tropical Medicine and Hygiene 48 (2): 139–45.

5. Bearcroft, W.G. (September 1956). "Zika virus infection experimentally induced in a human volunteer." Transactions of the Royal Society of Tropical Medicine and Hygiene 50 (5): 442–8. 6. Tai-Ho Chen, M.D., W. et al. Zika Virus Outbreak on Yap Island, Federated States of Micronesia. Mark R. Duffy, D.V.M., M.P.H., N Engl J Med 2009; 360:2536-2543

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CITATIONS

7. Search and one will find: Zika virus everywhere Trans R Soc Trop Med

Hyg (2016)110 (4): 207-208.doi: 10.1093/trstmh/trw020. 8. Musso D. Zika virus transmission from French Polynesia to

Brazil. Emerg Infect Dis. 2015;21(10):1887.

9. Camila Zanluca et al. Mem. Inst. Oswaldo Cruz vol.110 no.4 Rio de Janeiro June 2015 Epub June 09, 2015. 10. Zika Virus: New Clinical Syndromes and Its Emergence in the Western Hemisphere. Helen M. Lazear and Michael S.

Diamond. J. Virol. May 2016 vol. 90 no. 104864-4875

11. Troncoso A, Zika threatens to become a huge worldwide

pandemic. Asian Pac J Trop Biomed (2016)

12. Anthony S. Fauci, M.D., and David M. Morens, M.D. Zika Virus in the Americas — Yet Another Arbovirus Threat. N Engl J Med 2016; 374:601-604.

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