ZIKA VIRUS (20) - AMERICAS, ASIA, RESEARCH, OBSERVATIONS

Posted on 25TH SEP 2017
tagged Zika Virus, Americas; Asia

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

Asia
---
Taiwan ex Philippines
Viet Nam (Vinh Long province)

Imported cases with little or no possibility of ongoing mosquito transmission
USA:
- Case numbers mainland
- Territories and Commonwealth

[2] Persistence in sperm and fluids
[3] Ongoing sexual transmission
[4] Vaccine and pregnancy
[5] Zika virus encephalitis in adult

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[1] Cases in various countries
Americas cumulative case numbers
As of 21 Sep 2017
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 / 523 / 0 / 1
USA / 0 / 225 / 5190 / 0 / 98

Latin America:
Mexico / 0 / 9855 / 15 / 0 / 20

Central American Isthmus:
Belize / 1930 / 330 / 0 / 0 / 0
Costa Rica / 7456 / 1950 / 32 / 0 / 6
El Salvador / 11 674 / 51 / 0 / 0 / 4
Guatemala / 3822 / 1000 / 0 / 0 / 140
Honduras / 32 385 / 308 / 0 / 0 / 8
Nicaragua / 0 / 2060 / 3 / 0 / 2
Panama / 5261 / 1114 / 42 / 0 / 13

Latin Caribbean:
Cuba / 0 / 187/ 58 / 0 / 0
Dominican Republic / 4919 / 335 / 0 / 0 / 85
French Guiana / 10 500 / 483 / 10 / 0 / 1
Guadeloupe / 30 845 / 382 / 0 / 0 / 5
Haiti / 2955 / 5 / 0 / 0 / 1
Martinique / 36 680 / 21 / 0 / 0 / 5
Puerto Rico / 0 / 40 588 / 137 / 5 / 47
Saint Barthelemy / 1005 / 61 / 0 / 0 / 0
Saint Martin / 3283 / 200 / 0 / 0 / 1

Non-Latin Caribbean:
Anguilla / 31 / 23 / 1/ 0 / 0
Antigua and Barbuda / 540 / 25 / 2 / 0 / 0
Aruba / 1208 / 703 / 7 / 0 / 0
Bahamas / 531 / 25 / 3/ 0 / 0
Barbados / 715 / 150 / 0 / 0 / 1
Bonaire, St Eustatius and Saba / 235 / 437 / 0 / 0 / 0
Caymans / 237 / 30 / 11 / 0 / 0
Curacao / 4476 / 2049 / 0 / 0 / 0
Dominica / 1154 / 79 / 0 / 0 / 0
Grenada / 335 / 118 / 0 / 0 / 2
Guyana / 0 / 37 / 0 / 0 / 3
Jamaica / 7772 / 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
Saint Maarten / 253 / 149 / 0 / 0 / 0
Suriname / 2768 / 724 / 0 / 4 / 4
Trinidad and Tobago / 0 / 718 / 1 / 0 / 17
Turks and Caicos / 203 / 25 / 3 / 0 / 0
Virgin Islands (UK) / 74 / 53 / 0 / 0 / 0
Virgin Islands (USA) / 1165 / 1024 / 2 / 0 / 0

Andean Area:
Bolivia / 2535 / 786 / 4 / 0 / 14
Colombia / 98 368 / 9839 / 0 / 0 / 248
Ecuador / 3753 / 3058 / 15 / 0 / 7
Peru / 6497 / 1517 / 22 / 0 / 0
Venezuela / 60 097 / 2413 / 0 / 0 / 0

[Brazil and] Southern Cone:
Brazil / 231 725 / 137 288 / 0 / 11 / 2952
Argentina / 539 / 276 / 40 / 0 / 2
Chile / 0 / 0 / 34 / 0 / 0
Paraguay / 668 / 18 / 0 / 0 / 2
Uruguay / 0 / 0 / 1 / 0 / 0

Totals, Americas / 580 496/ 221 093 / 6162 / 20 / 3689

[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]

Asia
---
Taiwan ex Philippines. 19 Sep 2017. (conf.) 4 imported cases ex: Vietnam (2 cases), the Philippines (1), and Angola (1); the most recent case is a 27-year-old male from Manila, the Philippines.
http://www.cdc.gov.tw/english/info.aspx?treeid=bc2d4e89b154059b&nowtreei...

[Maps of the Philippines can be accessed at:
http://tinyurl.com/z4y3p5v;
http://healthmap.org/promed/p/51664, and at
http://healthmap.org/promed/p/11107. - Mod.TY]

Viet Nam (Vinh Long province). 21 Sep 2017. (conf.) 1 case, the specific origin of the infection is unknown but within the country.
http://english.vietnamnet.vn/fms/society/186831/vinh-long-reports-1st-zi...

[A HealthMap/ProMED-mail map of Viet Nam can be accessed at:
http://healthmap.org/promed/p/152. - Mod.TY]

Imported cases with little or no possibility of ongoing mosquito transmission
---
USA:
- Case numbers in states. Zika virus disease in the United States, 1 Jan 2017 -20 Sep 2017
http://www.cdc.gov/zika/geo/united-states.html
State / Symptomatic cases / Viremic blood donors
Alabama / 3 / 0
Alaska / 1 / 0
Arizona / 1 / 0
Arkansas / 0 / 0
California / 25 / 2
Colorado / 4 / 0
Connecticut / 0 / 0
Delaware / 0 / 0
District of Columbia / 1 / 0
Florida / 53 / 3
Georgia / 1 / 0
Hawaii / 2 / 0
Idaho / 0 / 0
Illinois / 3/ 0
Indiana / 2 / 0
Iowa / 1 / 0
Kansas / 2 / 0
Kentucky / 2 / 0
Louisiana / 1 / 0
Maine / 1 / 0
Maryland / 9/ 0
Massachusetts / 9 / 0
Michigan / 7 / 0
Minnesota / 6/ 0
Mississippi / 2 / 0
Missouri / 1 / 0
Montana / 0 / 0
Nebraska / 1 / 0
Nevada / 1 / 0
New Hampshire / 0/ 0
New Jersey / 6 / 0
New Mexico / 0 / 0
New York / 47 / 1
North Carolina / 5 / 0
North Dakota / 0 / 0
Ohio / 3 / 0
Oklahoma / 1 / 0
Oregon / 4 / 0
Pennsylvania / 5/ 1
Rhode Island / 3 / 0
South Carolina / 2 / 0
South Dakota / 0 / 0
Tennessee / 0 / 0
Texas / 27 / 1
Utah / 4 / 0
Vermont / 3 / 0
Virginia / 6/ 0
Washington / 7 / 0
West Virginia / 1/ 1
Wisconsin / 3 / 0
Wyoming / 2 / 0
Totals / 268 / 9

- Territories and Commonwealth with local transmission:
Symptomatic / Blood donors
American Samoa 39 / 0
Puerto Rico 474 / 3
US Virgin Islands 41/ 0
Total 554 / 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

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[2] Persistence in sperm and fluids
Date: Mon 21 Aug 2017
Source: The Lancet Infectious Diseases [edited]
http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30444-9/abstract

Joguet G, Mansuy JM, Matusali G, et al. Effect of acute Zika virus infection on sperm and virus clearance in body fluids: a prospective observational study. Lancet Infect Dis. 2017. pii: S1473-3099(17)30444-9. doi: 10.1016/S1473-3099(17)30444-9. [Epub ahead of print]

Summary
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Background
Evidence of human sexual transmission during Zika virus emergence is a matter of concern, particularly in procreation, but to date, kinetics of seminal shedding and the effects of infection on human reproductive function have not been described. To investigate the effects of Zika virus infection on semen and clearance of Zika virus from semen and body fluids, we aimed to study a cohort of Zika virus-infected men.

Methods
This prospective observational study recruited men presenting with acute Zika virus infection at Pointe-a-Pitre University Hospital in Guadeloupe, French Caribbean, where a Zika virus outbreak occurred between April and November, 2016. Blood, urine, and semen were collected at days 7, 11, 20, 30, 60, 90, and 120 after symptom onset, and semen characteristics, such as total sperm count, sperm motility, vitality, and morphology, and reproductive hormone concentrations, such as testosterone, inhibin, follicle-stimulating hormone, and luteinising hormone, were assessed. At days 7, 11, and 20, semen was processed to isolate motile spermatozoa. Zika virus RNA was detected by RT-PCR using whole blood, serum, urine, seminal plasma, semen cells, and motile spermatozoa fractions. Zika virus was isolated from different sperm fractions on Vero E6 cultures.

Findings
A total of 15 male volunteers (mean age 35 years [SD 5; range 25-44]) with acute Zika virus infection and positive Zika virus RNA detection in blood or urine were enrolled. Total sperm count was decreased from median 119 x 10^6 spermatozoa (IQR 22-234) at day 7 to 45 x 10^6 (16.5-89.6) at day 30 and 70 x 10^6 (28.5-81.4) at day 60, respectively, after Zika virus infection. Inhibin values increased from 93.5 pg/mL (IQR 55-162) at day 7 to 150 pg/mL (78-209) at day 120 when total sperm count recovered. In motile spermatozoa obtained after density gradient separation, Zika virus RNA was found in 3 of 14 patients at day 7, 4 of 15 at day 11, and 4 of 15 at day 20, and replication-competent virus was found in the tested patient. Seminal shedding kinetics seemed heterogeneous among patients. Whole blood was the fluid most frequently positive for Zika virus RNA (62 of 92 samples) and 3 patients remained positive at day 120.

Interpretation
Semen alterations early after acute Zika virus infection might affect fertility and could be explained by virus effects on the testis and epididymis. Frequency of shedding and high viral load in semen, together with the presence of replicative virus in a motile spermatozoa fraction, can lead to Zika virus transmission during sexual contact and assisted reproduction procedures. Whole blood seems to be the best specimen for Zika virus RNA detection, diagnosis, and follow-up.

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Communicated by:
Roland Hübner
Superior Health Council
Brussels
Belgium

[This study addresses 2 important questions that have been raised from the previous studies that detected Zika virus RNA in semen and seminal fluids: is transmissible virus present in those RNA positive specimens and are there effects on spermatozoa that could affect fertility. In the above study, replication-competent Zika virus was found in motile spermatozoa at post-infection day 20. Additional studies will be necessary to determine if active virus occurs in those infected men beyond 20 days, and in those individuals who have detectable Zika virus RNA for up to 6 months. The above study clearly demonstrates that Zika virus infections of testis and epididymis can decrease sperm numbers and an increase of multiple sperm anomalies, especially in patients with Zika virus RNA-positive seminal specimens that could adversely affect fertility. Interesting comments on this study were published by Barzon, Lavezzo and Palu in that same journal issue ( Published online on [21 Aug 2017] http://dx.doi.org/10.1016/S1473-3099(17)30495-4). - Mod.TY]

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[3] Ongoing sexual transmission
Date: Thu 21 Sep 2017
Source: PLoS Pathogens [edited]
http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1...

Allard A, Althouse BM, Hébert-Dufresne L, Scarpino SV. The risk of sustained sexual transmission of Zika is underestimated. PLoS Pathog. 2017;13(9):e1006633. doi: 10.1371/journal.ppat.1006633. [Epub ahead of print]

Abstract
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Pathogens often follow more than one transmission route during outbreaks--from needle sharing plus sexual transmission of HIV to small droplet aerosol plus fomite transmission of influenza. Thus, controlling an infectious disease outbreak often requires characterizing the risk associated with multiple mechanisms of transmission. For example, during the Ebola virus outbreak in West Africa, weighing the relative importance of funeral versus health care worker transmission was essential to stopping disease spread. As a result, strategic policy decisions regarding interventions must rely on accurately characterizing risks associated with multiple transmission routes. The ongoing Zika virus (ZIKV) outbreak challenges our conventional methodologies for translating case-counts into route-specific transmission risk. Critically, most approaches will fail to accurately estimate the risk of sustained sexual transmission of a pathogen that is primarily vectored by a mosquito--such as the risk of sustained sexual transmission of ZIKV. By computationally investigating a novel mathematical approach for multi-route pathogens, our results suggest that previous epidemic threshold estimates could under-estimate the risk of sustained sexual transmission by at least an order of magnitude. This result, coupled with emerging clinical, epidemiological, and experimental evidence for an increased risk of sexual transmission, would strongly support recent calls to classify ZIKV as a sexually transmitted infection.

Author summary
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The national and international community is grappling with how to respond to the ongoing Zika virus outbreak. One of the most uncertain aspects of this disease is its potential for sustained sexual transmission. Recent studies have suggested that there are large differences in the age- and sex-specific Zika virus attack rates--with women of childbearing age having the highest incidence of infection--and that the risk of sustained sexual transmission may be low. Here we investigate the novel epidemiological behavior of an infection that is transmitted both sexually and by a mosquito vector. Using data-driven simulations, we demonstrate how conventional methods can substantially underestimate the risk of sustained sexual transmission for Zika outbreaks. More specifically, we find that the threshold for large-scale, sustained sexual transmission could easily be underestimated by a factor of 10 or higher using existing models. Finally, we discuss how such an underestimate will lead to ineffective responses and a drastic underestimation of the risk associated with Zika persistence and re-emergence.

Discussion
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Sustained sexual transmissions of ZIKV in the MSM community would lead to sporadic sub-critical, but potentially dramatic spillover outbreaks in the heterosexual community, and would increase the probability of endemic establishment of ZIKV. Our result that sexual transmission increases the potential epidemic size and the probability of establishment supports earlier findings from Gao et al. (2016). Public health decision- and policy-makers rely on accurate characterizations of transmission risk to decide on interventions and strategically allocate limited resources. For pathogens, like ZIKV which are both vectored by an insect and transmitted sexually (with sex-based asymmetry in transmission rate), conventional approaches will underestimate the risk associated with sexual transmission. Underestimating the risk of sexual transmission, both in terms of the average transmission risk and variation in transmission risk, will lead both to biased intervention efforts and to an underestimate of the potential for disease persistence. Additionally, given the differential rates of ZIKV testing in MSM versus non-MSM communities and the known heterogeneity between their contact distributions, the data on sexual transmission are almost certainly biased. We also do not have sufficient experimental or epidemiological evidence for the per-contact probability of transmission in the MSM community. Here we advocate for the decision-making and disease modeling communities to better embrace contact network methods when characterizing transmission risk and for increased ZIKV testing in both MSM and non-MSM communities. The resulting estimates of transmission risk and the key epidemiological measures, e.g Ro and the likelihood of disease persistence, will be more accurate.

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Communicated by:
ProMED-mail

[The authors point out that both heterosexual transmission and between men who have sex with men (MSM) have been documented. So far, observations of instances of sexual transmission have overwhelmingly been men to women. However, the authors state that given the high level of asymmetry between probabilities of men-to-women and women-to-men transmissions, there is a potential for sustained epidemics within the MSM community but sub-critical in the rest of the population. This statistical model and its conclusions deserve verification in the populations at risk. Because mosquito transmission of Zika virus in the population in area of risk are common, determination of MSM sustained transmission would have to be determined in areas without active mosquito transmission. - Mod.TY]

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[4] Vaccine and pregnancy
Date: Fri 22 Sep 2017
Source: Nature Communications [edited]
https://www.nature.com/articles/s41467-017-00737-8

Shan C, Muruato AE, Jagger BW, et al. A single-dose live-attenuated vaccine prevents Zika virus pregnancy transmission and testis damage. Nat Commun. 2017;8(1):676. doi: 10.1038/s41467-017-00737-8.

Abstract
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Zika virus infection during pregnancy can cause congenital abnormities or fetal demise. The persistence of Zika virus in the male reproductive system poses a risk of sexual transmission. Here we demonstrate that live-attenuated Zika virus vaccine candidates containing deletions in the 3' untranslated region of the Zika virus genome (ZIKV-3'UTR-LAV) prevent viral transmission during pregnancy and testis damage in mice, as well as infection of nonhuman primates. After a single-dose vaccination, pregnant mice challenged with Zika virus at embryonic day 6 and evaluated at embryonic day 13 show markedly diminished levels of viral RNA in maternal, placental, and fetal tissues. Vaccinated male mice challenged with Zika virus were protected against testis infection, injury, and oligospermia. A single immunization of rhesus macaques elicited a rapid and robust antibody response, conferring complete protection upon challenge. Furthermore, the ZIKV-3'UTR-LAV vaccine candidates have a desirable safety profile. These results suggest that further development of ZIKV-3'UTR-LAV is warranted for humans.

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Communicated by:
ProMED-mail Rapporteur Mary Marshall

[The results of these tests in mice indicated that vaccination protects against testis infection and reduces virus RNA in maternal, placental and fetal tissues. Although immunization elicited a protective antibody response in rhesus macaques, the next step will be to vaccinate pregnant rhesus macaques and determine if protection is provided to placental tissue and fetuses. - Mod.TY]

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[5] Zika virus encephalitis in adult
Date: Sun 24 Sep 2017
Source: Occup Med Health Aff [edited]
https://www.omicsonline.org/open-access/zika-virus-encefalitis-2329-6879...

Gonzalez LZ, Vergara JC, Jauregui JS. Zika Virus Encephalitis. 5(3): 306. doi: 10.4172/2329-6879.1000306

Clinical Image
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A male, 23 years old, pancreatitis and cholecystectomy 1 month ago, presented to our Emergency Department with a history of 6 days of fever, dizziness and confusion. He reported no headache, neck stiffness or seizures. Physical examination the patient was somnolent, with reactive isochoric pupils, quadriparetic with hyporeflexia. He became stuporous with shock and leukocytosis. Treatment with meropenem and vancomycin were initiated empirically. Magnetic resonance imaging (MRI) of the brain revealed hyper intense lesions in the brain stem, fornix and bilateral thalamus (Figures 1A and 1B) with no midline shift. The CSF analysis results were non-specific with mild protein elevation. CSF molecular biology testing with PCR RNA for Zika virus was positive. A diagnosis of acute disseminated Zika virus encephalitis was made. Immunomodulatory therapy with IVIG was initiated. Follow-up MRI of the brain showed progression of lesions to midbrain, basal ganglia and brain cortex (Figures 1C and 1D). He had no response to 5 days of IVIG therapy and subsequently the patient died.

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Communicated by:
ProMED-mail

[This reports another case of the neuropathological consequences of Zika virus infection in an adult. Readers interested in this case can view the MRI images in the original article available at the above URL. - Mod.TY]

[Although individual country reports of Zika infections has decreased over the past week, the increases in cases in the Americas reported by PAHO/WHO and in cases in states in the USA indicate that transmission of the virus continues. Travelers to affected countries should take precautions to avoid mosquito bites or situations that could lead to sexual transmission. - Mod.TY]

See Also

Zika virus (19): Americas, research, observations 20170917.5322171
Zika virus (18): Americas, research, observations 20170908.5303860
Zika virus (17): Americas, research, observations 20170830.5283102
Zika virus (16): Americas, Asia, research, observations 20170819.5261363
Zika virus (15): Americas, research, observations 20170701.5144254
Zika virus (14): Americas, Asia, research, observations 20170623.5127418
Zika virus (13): Americas, research, observations 20170617.5112404
Zika virus (12): Americas, Asia, research, observations 5099103
Zika virus (11): Americas, research, observations 20170604.5083731
Zika virus (10): Americas, Asia, Middle East, research 20170529.5069572
Zika virus (09): Americas, Asia, Europe, research, observations 20170517.5043638
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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