ZIKA VIRUS (09: AMERICAS, ASIA, EUROPE, RESEARCH, OBSERVATIONS

Posted on 18TH MAY 2017
tagged Zika Virus, Americas; Asia; Europe

A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org

In this update:
[1] Cases in various countries:
Americas
Americas cumulative case numbers
North America
Florida
Central America
Belize
Costa Rica
Honduras
Caribbean
USA Virgin Islands (St. Thomas)
South America
Brazil
Ecuador
Imported cases with no possibility of ongoing mosquito transmission
China (Jiangsu province)
Romania
USA:
Case numbers mainland
Texas
Territories and Commonwealth
[2] Neonate postmortem findings
[3] Abnormal fetal MRIs
[4] CDC: Interpreting test results for pregnant women
[5] _Aedes vexans_ susceptibility
[6] Virus-like particle vaccine
[7] Antiviral drug
[8] Diagnostic test
[9] Economic burden USA

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[1] Cases in various countries
Americas
Americas cumulative case numbers
Date: Thu 11 May 2017
Source: World Health Organization [edited]
http://www.paho.org/hq/index.php?option=com_content&view=article&id=1239...

Country / Locally acquired: suspected / Confirmed /Imported / Deaths / Conf. Congenital Syndrome
North America:
Bermuda / 0 / 0 / 6 / 0 / 0
Canada / 0 / 0 / 499 / 0 / 1
USA / 0 / 225 / 4973 / 0 / 66

Latin America:
Mexico / 0 / 8731 / 15 / 0 / 5

Central American Isthmus:
Belize / 1294 / 206 / 0 / 0 / 0
Costa Rica / 6327 / 1800 / 32 / 0 / 5
El Salvador / 11 499 / 51 / 0 / 0 / 4
Guatemala / 3634 / 921 / 0 / 0 / 59
Honduras / 32 130 / 302 / 0 / 0 / 4
Nicaragua / 0 / 2060 / 3 / 0 / 2
Panama / 4178 / 969 / 42 / 0 / 7

Latin Caribbean:
Cuba / 0 / 187/ 58 / 0 / 0
Dominican Republic / 4906 / 345 / 0 / 0 / 54
French Guiana / 10 385 / 483 / 10 / 0 / 17
Guadeloupe / 30 845 / 382 / 0 / 0 / 18
Haiti / 2955 / 5 / 0 / 0 / 1
Martinique / 36 680 / 21 / 0 / 0 /23
Puerto Rico / 0 / 40 139 / 137 / 5 / 29
Saint Barthelemy / 990 / 61 / 0 / 0 / 0
Saint Martin / 3280 / 200 / 0 / 0 / 1

Non-Latin Caribbean:
Anguilla / 29 / 23 / 1/ 0 / 0
Antigua and Barbuda / 465 / 14 / 2 / 0 / 0
Aruba / 1208 / 468 / 7 / 0 / 0
Bahamas / 0 / 25 / 3/ 0 / 0
Barbados / 705 / 150 / 0 / 0 / 1
Bonaire, St Eustatius and Saba / 235 / 381 / 0 / 0 / 0
Caymans / 232 / 31 / 10 / 0 / 0
Curacao / 2589 / 1259 / 0 / 0 / 0
Dominica / 1154 / 79 / 0 / 0 / 0
Grenada / 336 / 117 / 0 / 0 / 2
Guyana / 0 / 37 / 0 / 0 / 0
Jamaica / 7655 / 203 / 0 / 0 / 0
Montserrat / 18 / 5 / 0 / 0 / 0
Saint Kits and Nevis / 554/ 33 / 0 / 0 / 0
Saint Lucia / 822 / 50 / 0 / 0 / 0
Saint Vincent and the Grenadines / 508 / 83 / 0 / 0 / 0
Sint Maarten / 247 / 147 / 0 / 0 / 0
Suriname / 2768 / 723 / 0 / 4 / 4
Trinidad and Tobago / 0 / 718 / 1 / 0 / 3
Turks and Caicos / 201/ 25 / 3 / 0 / 0
Virgin Islands (UK) / 74 / 52 / 0 / 0 / 0
Virgin Islands (USA) / 1093 / 1026 / 2 / 0 / 0

Andean Area:
Bolivia / 1767 / 585 / 4 / 0 / 14
Colombia / 97 936 / 9802 / 0 / 0 / 150
Ecuador / 3972 / 1330 / 15 / 0 / 3
Peru / 4782 / 1006 / 22 / 0 / 0
Venezuela / 5965 / 2413 / 0 / 0 / 0

[Brazil and] Southern Cone:
Brazil / 223 330 / 133 527 / 0 / 11 / 2653
Argentina / 869 / 86 / 40 / 0 / 2
Chile / 0 / 0 / 34 / 0 / 0
Paraguay / 651 / 14 / 0 / 0 / 2
Uruguay / 0 / 0 / 1 / 0 / 0

Totals, Americas / 553 168 / 211 500 / 5920 / 20 / 3130

[Maps showing the location of the affected islands and countries in the Americas mentioned above and below
can be accessed at
http://healthmap.org/promed/p/35574;
North America at http://healthmap.org/promed/p/106;
Central America http://healthmap.org/promed/p/39455;
Caribbean http://www.mapsofworld.com/caribbean-islands/ and
South America at http://healthmap.org/promed/p/6186. - Mod.TY]

North America
Florida. 3 May 2017. (reported) 4000 _Wolbachia_-infected male _Aedes aegypti_ are released per week on Stock Island, near Key West to reduce the population of these Zika virus vector mosquitoes.
http://www.foxnews.com/health/2017/05/03/zika-fight-bacteria-laden-mosqu...

Central America
Belize. 13 May 2017. (conf.) 124 cases this year (2017); Northern Belize most affected: Corozal 94 cases, Orange Walk 23 cases.
http://amandala.com.bz/news/zika-takes-root-northern-belize/

Costa Rica. 16 May 2017. (susp.) in 1st 16 weeks of 2017, 759 cases (conf.) 152 cases of whom 26 pregnant; Probable Zika virus congenital syndrome 3 cases.
http://www.plenglish.com/index.php?o=rn&id=12967&SEO=zika-chikungunya-de...

Honduras. 1 May 2017. (reported) 155 cases this year (2017); Microcephaly 200 cases in 9 months attributed to _Aedes aegypti_ transmitted Zika virus infection.
http://spanish.china.org.cn/international/txt/2017-05/01/content_4072339...
[Report provided by Kathryn Soderholm ]

Caribbean
USA Virgin Islands (St. Thomas). 7 May 2017. From January 2016 - 1 May 2017 (susp.) 7744 cases, (conf.) 203 cases; Microcephaly (reported) 181 cases of which (susp.) 51 cases, 35 non-severe, 12 severe, 3 probable.
http://jamaica-gleaner.com/article/lead-stories/20170507/st-thomas-zika-...

South America
Brazil. 12 May 2017. (reported) January - 15 April 7911 cases (compared to 170 535 cases for the same period in 2016); Microcephaly and other central nervous system disorders (susp., under investigation) 2837 cases (conf.) 230 cases in 2017, since November 2015, 2653 cases; Zika emergency declared over on 11 May 2017.
http://riotimesonline.com/brazil-news/rio-politics/brazil-lifts-state-of...

Ecuador. 5 May 2017. Since April 2016, (reported) 400 Zika virus infected pregnant women in 8 provinces; 9 other women with vertical virus transmission to their fetuses and 3 cases of fetal malformation.
https://www.elcomercio.com/tendencias/neonatos-microcefalia-ministeriode... [in Spanish]

Imported cases with no possibility of ongoing mosquito transmission
China (Jiangsu province). 13 May 2017. (conf.) 1 case ex Ecuador.
http://www.military-technologies.net/2017/05/13/chp-closely-monitors-fir...

[A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/155.]

Romania. 1 May 2017. (conf.) the 1st 2 cases of imported infection reported in the country in July 2016.
http://online.liebertpub.com/doi/full/10.1089/vbz.2016.2076

[A HealthMap/ProMED-mail map of Europe sowing the location of Romania can be found at http://healthmap.org/promed/p/75.]

USA:
Case numbers mainland. Zika virus disease in the United States, 1 Jan 2017 - 10 May 2017
http://www.cdc.gov/zika/geo/united-states.html
State/ Symptomatic cases / Viremic blood donors
Alabama 3 / 0
Arizona 1 / 0
Arkansas 0 / 0
California 12 / 1
Colorado 3 / 0
Connecticut 0 / 0
Delaware 0 / 0
District of Columbia 0 / 0
Florida 12 / 3
Georgia 1 / 0
Hawaii 0 / 0
Idaho 0 / 0
Illinois 2/ 0
Indiana 1 / 0
Iowa 1 / 1
Kansas 2 / 0
Kentucky 1 / 0
Louisiana 1 / 0
Maine 1 / 0
Maryland 3 / 0
Massachusetts 5 / 1
Michigan 6 / 0
Minnesota 0 / 0
Mississippi 2 / 0
Missouri 1 / 0
Montana 0 / 0
Nebraska 0 / 0
Nevada 0 / 0
New Hampshire 0/ 0
New Jersey 2 / 0
New Mexico 0 / 0
New York 18 / 1
North Carolina 3 / 0
North Dakota 0 / 0
Ohio 3 / 0
Oklahoma 0 / 0
Oregon 1 / 0
Pennsylvania 3 / 0
Rhode Island 2 / 0
South Carolina 0 / 0
South Dakota 0 / 0
Tennessee 0 / 0
Texas 10 / 1
Utah 0 / 0
Vermont 2 / 0
Virginia 3 / 0
Washington 2 / 0
West Virginia 0 / 1
Wisconsin 2 / 0
Wyoming 2 / 0
Total 110/ 7

Texas. 5 May 2017. (reported) 18 pregnant Zika virus infected women, 2 babies with microcephaly, 7 normal and 9 pregnancies ongoing.
http://www.cbsnews.com/news/mosquito-season-pregnant-women-texas-zika/
[Report provided by ProMED-mail Rapporteur Mary Marshall.]

Territories and Commonwealth:
Symptomatic / Blood donors
American Samoa 3 / 0
Puerto Rico 456 / 3
US Virgin Islands 34 / 0
Total 493/ 3
[A map of the USA showing the states and territories mentioned above can be accessed at
http://www.mapsofworld.com/usa/]

--
Communicated by:
ProMED-mail

and
Roland Hubner
Superior Health Council
Brussels
Belgium

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[2] Neonate postmortem findings
Date: July 2017 ahead of print
Source: Emerg Infect Dis https://doi.org/10.3201/eid2307.162019 [edited]
https://wwwnc.cdc.gov/eid/article/23/7/16-2019_article

Sousa AQ, Cavalcante DIM, Franco LM, Araújo FMC, Sousa ET, Valença-Junior JT, et al. Postmortem findings for 7 neonates with congenital Zika virus infection.

Abstract
Postmortem examination of 7 neonates with congenital Zika virus infection in Brazil revealed microcephaly, ventriculomegaly, dystrophic calcifications, and severe cortical neuronal depletion in all and arthrogryposis in 6. Other findings were leptomeningeal and brain parenchymal inflammation and pulmonary hypoplasia and lymphocytic infiltration in liver and lungs. Findings confirmed virus neurotropism and multiple organ infection.

--
Communicated by:
ProMED-mail

[ProMED-mail readers interested in the details of these post mortems can find them at the above URL. - Mod.TY]

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[3] Abnormal fetal MRIs
Date: Thu 4 May 2017
Source: Children's National Health System through Science Daily [edited]
https://www.sciencedaily.com/releases/2017/05/170504131707.htm

During a recent trip Sarah B. Mulkey, M.D., Ph.D., made to Colombia, where Children's National Health System researchers are collaborating on a clinical study, she tested Zika-affected babies' motor skills as they sat, stood, and lay facing upward and face down. The international study aims to answer one of the most vexing questions about Zika: If babies' brains appear "normal" at birth, have they survived Zika exposure in the womb with few neurological repercussions?

The research sought to evaluate the utility of using magnetic resonance imaging (MRI) to evaluate fetal brain abnormalities in 48 babies whose mothers had confirmed Zika infection during pregnancy. Of the women/infant pairs enrolled in the prospective study, 46 are Colombian, and 2 are Washington, D.C. women who were exposed during travel to a Zika hot zone.

Among the 48 study participants, 45 had "normal" fetal MRIs; 3 fetuses exposed to Zika in the 1st or 2nd trimester had abnormal fetal MRI:
- One had heterotopia and an early, abnormal fold on the surface of the brain, indications that neurons did not migrate to their anticipated destination during fetal brain development. This pregnancy was terminated at 23.9 gestational weeks.
- One had parietal encephalocele, a rare birth defect that results in a sac-like protrusion of the brain through an opening in the skull. According to the CDC, this defect affects one in 12 200 births, or 340 babies, per year. It is not known if this rare finding is related to Zika infection.
- One had a thin corpus callosum, dysplastic brainstem, heterotopias, significant ventriculomegaly and generalized cerebral/cerebellar atrophy.
Dr. Mulkey says. "The vast majority of fetuses exposed to Zika in our study had normal fetal MRI, however. Our ongoing study, underwritten by the Thrasher Research Fund, will evaluate their long-term neurodevelopment."

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Communicated by:
ProMED-mail

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[4] CDC: Interpreting test results for pregnant women
Date: Fri 5 May 2017
Source: CDC Emergency Preparedness and Response [edited]
https://emergency.cdc.gov/han/han00402.asp

Prolonged IgM Antibody Response in People Infected with Zika Virus: Implications for Interpreting Serologic Testing Results for Pregnant Women

Summary
In July 2016, CDC issued Interim Guidance for Health Care Providers Caring for Pregnant Women with Possible Zika Virus Exposure - United States, July 2016 (https://www.cdc.gov/mmwr/volumes/65/wr/mm6529e1.htm) that includes Zika virus immunoglobulin M (IgM) testing of pregnant women. However, some flavivirus infections can result in prolonged IgM responses (>12 weeks) that make it difficult to determine the timing of infection, especially in testing of asymptomatic people. Emerging epidemiologic and laboratory data indicate that Zika virus IgM can persist beyond 12 weeks in a subset of infected people. Therefore, detection of IgM may not always indicate a recent infection. Although IgM persistence could affect IgM test interpretation for all infected people, it would have the greatest effect on clinical management of pregnant women with a history of living in or traveling to areas with Zika virus transmission before conception. Pregnant women who test positive for IgM antibody may have been infected with Zika virus and developed an IgM response before conception.

For asymptomatic pregnant women living in or frequently traveling to areas with Zika virus transmission, Zika virus nucleic acid test (NAT) testing at least once per trimester should be considered, in addition to IgM testing as previously recommended. If positive, this may provide a more definitive diagnosis of recent Zika infection. However, a negative NAT does not rule out recent infection because viral ribonucleic acid (RNA) declines over time. Other diagnostic methods, such as NAT testing of amniocentesis specimens or serial ultrasounds, may provide additional information to help determine whether the IgM test results suggest a recent infection. Providers should counsel women on the limitations of all tests. In addition, providers may wish to consider IgM testing as part of pre-conception counseling to establish baseline IgM results before pregnancy; however, preconception negative IgM results might have limited value for women at ongoing risk of Zika infection. NAT testing should be performed for any pregnant woman who becomes symptomatic or who has a sexual partner who tests positive for Zika virus infection.

Recommendations
For asymptomatic pregnant women living in or frequently traveling to areas with Zika virus transmission with posted CDC Zika Travel Notices (https://wwwnc.cdc.gov/travel/page/zika-information), CDC recommends that healthcare providers take these steps:
- Screen pregnant women for risk of Zika exposure and symptoms of Zika. Promptly test pregnant women with NAT if they become symptomatic during their pregnancy or if a sexual partner tests positive for Zika virus infection.
- Consider NAT testing at least once per trimester, unless a previous test has been positive.*
- Consider NAT testing of amniocentesis specimens if amniocentesis is performed for other reasons.
- Counsel pregnant women each trimester on the limitations of IgM and NAT testing. For more information about Zika virus testing, see: https://www.cdc.gov/zika/pdfs/living_in.pdf. For more information about counseling before testing, see: https://www.cdc.gov/zika/pdfs/pretestingcounselingscript_livingin.pdf.
- Consider IgM testing to determine baseline Zika virus IgM levels as part of preconception counseling. For more information about preconception counseling, see: https://www.cdc.gov/zika/pdfs/preconception-counseling.pdf

Recommendations for testing symptomatic pregnant women, remain unchanged (https://www.cdc.gov/mmwr/volumes/65/wr/mm6529e1.htm). However, if a symptomatic pregnant woman is IgM positive and NAT negative, and lived in or traveled to an area with a posted CDC Zika Travel Notice (https://wwwnc.cdc.gov/travel/page/zika-information), healthcare providers should recognize that the positive IgM result does not necessarily indicate recent infection.

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Communicated by:
ProMED-mail

[This CDC update will be helpful for medical care givers attending pregnant women. In general, in May 2017, the CDC has issued a new Zika interim response plan (https://www.cdc.gov/zika/public-health-partners/cdc-zika-interim-respons..., sent in by ProMED-mail Rapporteur Mary Marshall)]

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[5] _Aedes vexans_ susceptibility
Date: Fri 12 May 2017
Source: J Med Entomol tjx087 DOI:https://doi.org/10.1093/jme/tjx087 [edited]
https://academic.oup.com/jme/article/3797264/Potential-of-a-Northern-Pop...

Kyle L. O'Donnell, Mckenzie A. Bixby, Kelsey J. Morin, David S. Bradley, Jefferson A. Vaughan. Potential of a Northern Population of _Aedes vexans_ (Diptera: Culicidae) to Transmit Zika Virus.

Abstract
Zika virus is an emerging arbovirus of humans in the western hemisphere. With its potential spread into new geographical areas, it is important to define the vector competence of native mosquito species. We tested the vector competency of _Aedes vexans_ (Meigen) from the Lake Agassiz Plain of northwestern Minnesota and northeastern North Dakota. _Aedes aegypti_ (L.) was used as a positive control for comparison. Mosquitoes were fed blood containing Zika virus and 2 week later were tested for viral infection and dissemination. _Aedes vexans_ (n = 60) were susceptible to midgut infection (28 percent infection rate) but displayed a fairly restrictive midgut escape barrier (3 percent dissemination rate). Cofed _Ae. aegypti_ (n = 22) displayed significantly higher rates of midgut infection (61 percent) and dissemination (22 percent). To test virus transmission, mosquitoes were inoculated with virus and 16-17 days later, tested for their ability to transmit virus into fluid-filled capillary tubes. Unexpectedly, the transmission rate was significantly higher for _Ae. vexans_ (34 percent n = 47) than for _Ae. aegypti_ (5 percent, n = 22). The overall transmission potential for _Ae. vexans_ to transmit Zika virus was 1 percent. Because of its wide geographic distribution, often extreme abundance, and aggressive human biting activity, _Ae. vexans_ could serve as a potential vector for Zika virus in northern latitudes where the conventional vectors, _Ae. aegypti_ and _Ae. albopictus_ Skuse, cannot survive. However, Zika virus is a primate virus and humans are the only amplifying host species in northern latitudes. To serve as a vector of Zika virus, _Ae. vexans_ must feed repeatedly on humans. Defining the propensity of _Ae. vexans_ to feed repeatedly on humans will be key to understanding its role as a potential vector of Zika virus.

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Communicated by:
ProMED-mail Rapporteur Mary Marshall

[Although Ae. vexans is extremely abundant in some areas of the Upper Midwest USA, a 1 percent potential for transmission and only 3 percent with gut barrier escape raises questions about their potential role as vectors in nature. The authors touch on a key point essential for efficient vector status - the frequency that _Ae. vexans_ refeeds on humans and not on other species. - Mod.TY]

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[6] Virus-like particle vaccine
Date: Mon 8 May 2017
Source: PLoS Neglected Tropical Diseases [edited]
http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005608

Hélène Boigard, Alexandra Alimova, George R. Martin, Al Katz, Paul Gottlieb, Jose M. Galarza. Zika virus-like particle (VLP) based vaccine.

Abstract
The newly emerged mosquito-borne Zika virus poses a major public challenge due to its ability to cause significant birth defects and neurological disorders. The impact of sexual transmission is unclear but raises further concerns about virus dissemination. No specific treatment or vaccine is currently available, thus the development of a safe and effective vaccine is paramount. Here we describe a novel strategy to assemble Zika virus-like particles (VLPs) by co-expressing the structural (CprME) and non-structural (NS2B/NS3) proteins, and demonstrate their effectiveness as vaccines. VLPs are produced in a suspension culture of mammalian cells and self-assembled into particles closely resembling Zika viruses as shown by electron microscopy studies. We tested various VLP vaccines and compared them to analogous compositions of an inactivated Zika virus (In-ZIKV) used as a reference. VLP immunizations elicited high titers of antibodies, as did the In-ZIKV controls. However, in mice the VLP vaccine stimulated significantly higher virus neutralizing antibody titers than comparable formulations of the In-ZIKV vaccine. The serum neutralizing activity elicited by the VLP vaccine was enhanced using a higher VLP dose and with the addition of an adjuvant, reaching neutralizing titers greater than those detected in the serum of a patient who recovered from a Zika infection in Brazil in 2015. Discrepancies in neutralization levels between the VLP vaccine and the In-ZIKV suggest that chemical inactivation has deleterious effects on neutralizing epitopes within the E protein. This along with the inability of a VLP vaccine to cause infection makes it a preferable candidate for vaccine development.

Author summary
Zika is an emerging mosquito-borne infection for which vaccines or specific treatments are not available to combat and control its rapid dissemination and deleterious effects. This work describes a novel strategy for the development of a virus-like particle (VLP) based Zika vaccine and shows its effectiveness when tested in a murine model. VLPs are non-infections mimics of the Zika virus, thus chemical inactivation is not required. A VLP vaccine is able to maintain native epitopes structures and to perform better than an inactivated Zika virus control. Our results show feasibility for the rapid development of a safe and potentially highly effective VLP based Zika vaccine for humans.

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Communicated by:
ProMED-mail

[It will be interesting to see if this VLP vaccine performs as well when the tests move up from mice to non-human primates. The duration of immunity will become a key parameter in those tests. - Mod.TY]

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[7] Antiviral drug
Date: July 2017 [ahead of print]
Source: Antiviral Research 143: 230-236 [edited] http://www.sciencedirect.com/science/article/pii/S0166354217300931

Irina C. Albulescu, Kristina Kovacikova, Ali Tas, Eric J. Snijder, Martijn J. van Hemert. Suramin inhibits Zika virus replication by interfering with virus attachment and release of infectious particles.

Highlights
- Suramin inhibits Zika virus replication in cell culture.
- Suramin interferes with Zika virus attachment to host cells.
- Suramin also affects release of infectious Zika virus.

Abstract
Zika virus (ZIKV) is a mosquito-borne flavivirus that mostly causes asymptomatic infections or mild disease characterized by low-grade fever, rash, conjunctivitis, and malaise. However, the recent massive ZIKV epidemics in the Americas have also linked ZIKV infection to fetal malformations like microcephaly and Guillain-Barré syndrome in adults, and have uncovered previously unrecognized routes of vertical and sexual transmission. Here we describe inhibition of ZIKV replication by suramin, originally an anti-parasitic drug, which was more recently shown to inhibit multiple viruses. In cell culture-based assays, using reduction of cytopathic effect as read-out, suramin had an EC 50 of ∼40 μM and a selectivity index of 48. In single replication cycle experiments, suramin treatment also caused a strong dose-dependent decrease in intracellular ZIKV RNA levels and a >3-log reduction in infectious progeny titers. Time-of-addition experiments revealed that suramin inhibits a very early step of the replication cycle as well as the release of infectious progeny. Only during the first 2 h of infection suramin treatment strongly reduced the fraction of cells that became infected with ZIKV, suggesting the drug affects virus binding/entry. Binding experiments at 4 C using ^35 S-labeled ZIKV demonstrated that suramin interferes with attachment to host cells. When suramin treatment was initiated post-entry, viral RNA synthesis was unaffected, while both the release of genomes and the infectivity of ZIKV were reduced. This suggests the compound also affects virion biogenesis, possibly by interfering with glycosylation and the maturation of ZIKV during its traffic through the secretory pathway. The inhibitory effect of suramin on ZIKV attachment and virion biogenesis and its broad-spectrum activity warrant further evaluation of this compound as a potential therapeutic.

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Communicated by:
ProMED-mail

[It will be interesting to see if suramin can inhibit Zika virus attachment and synthesis in vivo. One of the challenges in drug treatment of Zika virus infections is time of administration during the course of infection, since early on the symptoms of Zika virus infection are similar to those of infection by the dengue and chikungunya viruses. Also some 80 percent of Zika virus infections are asymptomatic or very mild, and those individuals are unlikely to seek medical attention and drug treatment. - Mod.TY]

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[8] Diagnostic test
Date: Wed 3 May 2017
Source: Science Translational Medicine: Vol. 9, Issue 388, eaag0538 DOI: 10.1126/scitranslmed.aag0538 [edited]
http://stm.sciencemag.org/content/9/388/eaag0538

Nunya Chotiwan, Connie D. Brewster, Tereza Magalhaes, James Weger-Lucarelli, Nisha K. Duggal et al. Rapid and specific detection of Asian- and African-lineage Zika viruses.

LAMP shines light on Zika virus
Rapid and simple assays to detect infectious agents are key to tracking emerging epidemics. Chotiwan et al. describe a loop-mediated amplification (LAMP) assay that detects Zika virus RNA in human biofluids such as serum and semen as well as in mosquitoes, the insect vector that transmits the disease. This approach successfully distinguished the Asian-lineage Zika virus, associated with the current outbreak in the Americas, from the African-lineage Zika virus. This LAMP assay should enable tracking of the Asian-lineage strain as it moves into new geographical locations. A key advantage of this approach is detection without the need for RNA purification or copying RNA into DNA.

Abstract
Understanding the dynamics of Zika virus transmission and formulating rational strategies for its control require precise diagnostic tools that are also appropriate for resource-poor environments. We have developed a rapid and sensitive loop-mediated isothermal amplification (LAMP) assay that distinguishes Zika viruses of Asian and African lineages. The assay does not detect chikungunya virus or flaviviruses such as dengue, yellow fever, or West Nile viruses. The assay conditions allowed direct detection of Zika virus RNA in cultured infected cells; in mosquitoes; in virus-spiked samples of human blood, plasma, saliva, urine, and semen; and in infected patient serum, plasma, and semen samples without the need for RNA isolation or reverse transcription. The assay offers rapid, specific, sensitive, and inexpensive detection of the Asian-lineage Zika virus strain that is currently circulating in the Western hemisphere, and can also detect the African-lineage Zika virus strain using separate, specific primers.

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Communicated by:
ProMED-mail from HealthMap Alerts

[There have been several recent diagnostic tests developed to detect Zika virus. This one looks promising. Its low cost is a major advantage. It will be interesting to see how it performs in the field with human or mosquito samples. - Mod.TY]

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[9] Economic burden USA
Date: Thu 27 Apr 2017
Source: PLoS Neglected Tropical Diseases [edited]
http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.000553...

Bruce Y. Lee ,Jorge A. Alfaro-Murillo, A lyssa S. Parpia, Lindsey Asti, Patrick T. Wedlock, Peter J. Hotez, Alison P. Galvani. The potential economic burden of Zika in the continental United States.

Abstract

Background
As the Zika virus epidemic continues to spread internationally, countries such as the United States must determine how much to invest in prevention, control, and response. Fundamental to these decisions is quantifying the potential economic burden of Zika under different scenarios.

Methodology/Principle findings
To inform such decision making, our team developed a computational model to forecast the potential economic burden of Zika across 6 states in the US (Alabama, Florida, Georgia, Louisiana, Mississippi, and Texas), which are at greatest risk of Zika emergence, under a wide range of attack rates, scenarios and circumstances. In order to accommodate a wide range of possibilities, different scenarios explored the effects of varying the attack rate from 0.01 percent to 10 percent. Across the 6 states, an attack rate of 0.01 percent is estimated to cost [USD] $183.4 million to society ($117.1 million in direct medical costs and $66.3 million in productivity losses), 0.025 percent would result in $198.6 million ($119.4 million and $79.2 million), 0.10 percent would result in $274.6 million ($130.8 million and $143.8 million) and 1 percent would result in $1.2 billion ($268.0 million and $919.2 million).

Conclusions
Our model and study show how direct medical costs, Medicaid costs, productivity losses, and total costs to society may vary with different attack rates across the 6 states and the circumstances at which they may exceed certain thresholds (e.g., Zika prevention and control funding allocations that are being debated by the US government). A Zika attack rate of 0.3 percent across the 6 states at greatest risk of Zika infection, would result in total costs that exceed $0.5 billion, an attack rate of 1 percent would exceed $1 billion, and an attack rate of 2 percent would exceed $2 billion.

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Communicated by:
ProMED-mail

[This model includes costs related to acute disease, infection of pregnant women at risk of infection of their fetuses, and long-term care of infants with Zika virus-caused birth defects. Although it may seem crass to equate disease and social disruption in terms of dollars, it does provide a measure useful when decisions about allocation of scarce funds need to be made. - Mod.TY]

[Zika virus transmission appears to be declining in much of the Americas. However, it would not be surprising if the virus has become endemic in many countries with sporadic cases occurring into the future. Continued surveillance and vector control will remain important. - Mod.TY

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/5626.]

See Also

Zika virus (08): Americas, Asia, research, observations 20170501.5005629
Zika virus (07): Americas, PAHO/WHO 20170429.5003908
Zika virus (06): Americas, Pacific, Asia, Africa, research 20170416.4974439
Zika virus (05): Americas, Pacific, Asia, research, observations 20170326.4927523
Zika virus (04): Americas, Asia Europe, research, observations 20170320.4912123
Zika virus (03): Americas, research 20170309.4888510
Zika virus (02): Americas, Asia, Africa, Pacific, research, observations 20170217.4846633
Zika virus (01): Americas, Asia, Africa, research 20170117.4772206
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