Zika Virus Risk Research Articles

Assessing the Risk of Zika Virus to Hong Kong Residents through invasion of Infected Mosquitoes through Seaports

Assessing the Risk of Zika Virus to Hong Kong Residents through invasion of Infected Mosquitoes through Seaports

Global risk model for vector-borne transmission of Zika virus reveals the role of El Niño 2015

Zika, a mosquito-borne viral disease that emerged in South America in 2015, was declared a Public Health Emergency of International Concern by the WHO in February of 2016. We developed a climate-driven R0 mathematical model for the transmission risk of Zika virus (ZIKV) that explicitly includes two key mosquito vector species: Aedes aegypti and Aedes albopictus The model was parameterized and calibrated using the most up to date information from the available literature. It was then driven by observed gridded temperature and rainfall datasets for the period 1950-2015. We find that the transmission risk in South America in 2015 was the highest since 1950. This maximum is related to favoring temperature conditions that caused the simulated biting rates to be largest and mosquito mortality rates and extrinsic incubation periods to be smallest in 2015. This event followed the suspected introduction of ZIKV in Brazil in 2013. The ZIKV outbreak in Latin America has very likely been fueled by the 2015-2016 El Niño climate phenomenon affecting the region. The highest transmission risk globally is in South America and tropical countries where Ae. aegypti is abundant. Transmission risk is strongly seasonal in temperate regions where Ae. albopictus is present, with significant risk of ZIKV transmission in the southeastern states of the United States, in southern China, and to a lesser extent, over southern Europe during the boreal summer season.

Zika and pregnancy: A comprehensive review.

Zika virus (ZIKV) infection is a well-nurtured topic for healthcare personnel nowadays. Central nervous system involvement including microcephaly and ocular involvements has already been reported in neonates of affected pregnant ladies. In this article, we have discussed these effects on the newborns of ZIKV-infected mothers. The proposed pathogenesis, modes of transmission of this infection from mothers to the fetuses, diagnosis of the cases and precaution for the pregnant ladies have also been discussed. We have gathered the recently available data on the risk of ZIKV for expectant mothers from PubMed, https://www.gov.uk/guidance/zika-virus as well as from centers for disease control and prevention websites.

More Evidence — This Time from Columbia — for an Associated Risk of Zika Virus and Guillain-Barré Syndrome

More Evidence — This Time from Columbia — for an Associated Risk of Zika Virus and Guillain-Barré Syndrome

Estimating the Number of Pregnant Women Infected With Zika Virus and Expected Infants With Microcephaly Following the Zika Virus Outbreak in Puerto Rico, 2016.

Zika virus (ZIKV) infection during pregnancy is a cause of congenital microcephaly and severe fetal brain defects, and it has been associated with other adverse pregnancy and birth outcomes. To estimate the number of pregnant women infected with ZIKV in Puerto Rico and the number of associated congenital microcephaly cases. We conducted a modeling study from April to July 2016. Using parameters derived from published reports, outcomes were modeled probabilistically using Monte Carlo simulation. We used uncertainty distributions to reflect the limited information available for parameter values. Given the high level of uncertainty in model parameters, interquartile ranges (IQRs) are presented as primary results. Outcomes were modeled for pregnant women in Puerto Rico, which currently has more confirmed ZIKV cases than any other US location. Zika virus infection in pregnant women. Number of pregnant women infected with ZIKV and number of congenital microcephaly cases. We estimated an IQR of 5900 to 10 300 pregnant women (median, 7800) might be infected during the initial ZIKV outbreak in Puerto Rico. Of these, an IQR of 100 to 270 infants (median, 180) may be born with microcephaly due to congenital ZIKV infection from mid-2016 to mid-2017. In the absence of a ZIKV outbreak, an IQR of 9 to 16 cases (median, 12) of congenital microcephaly are expected in Puerto Rico per year. The estimate of 5900 to 10 300 pregnant women that might be infected with ZIKV provides an estimate for the number of infants that could potentially have ZIKV-associated adverse outcomes. Including baseline cases of microcephaly, we estimated that an IQR of 110 to 290 total cases of congenital microcephaly, mostly attributable to ZIKV infection, could occur from mid-2016 to mid-2017 in the absence of effective interventions. The primary limitation in this analysis is uncertainty in model parameters. Multivariate sensitivity analyses indicated that the cumulative incidence of ZIKV infection and risk of microcephaly given maternal infection in the first trimester were the primary drivers of both magnitude and uncertainty in the estimated number of microcephaly cases. Increased information on these parameters would lead to more precise estimates. Nonetheless, the results underscore the need for urgent actions being undertaken in Puerto Rico to prevent congenital ZIKV infection and prepare for affected infants.

Zika virus: Endemic and epidemic ranges of Aedes mosquito transmission.

As evidence linking Zika virus with serious health complications strengthens, public health officials and clinicians worldwide need to know which locations are likely to be at risk for autochthonous Zika infections. We created risk maps for epidemic and endemic Aedes-borne Zika virus infections globally using a predictive analysis method that draws on temperature, precipitation, elevation, land cover, and population density variables to identify locations suitable for mosquito activity seasonally or year-round. Aedes mosquitoes capable of transmitting Zika and other viruses are likely to live year-round across many tropical areas in the Americas, Africa, and Asia. Our map provides an enhanced global projection of where vector control initiatives may be most valuable for reducing the risk of Zika virus and other Aedes-borne infections.

Prospective cohort study of pregnant Brazilian women elucidates link between Zika virus infection and fetal abnormalities.

Commentary on: Brasil P, Pereira JP Jr., Raja Gabaglia C, et al. Zika virus infection in pregnant women in Rio de Janeiro—preliminary report. N Engl J Med Published Online First: 4 May 2016. The Zika virus (ZIKV) epidemic in Brazil and discovery of population level association between this infection and fetal microcephaly was the beginning of recognition of a public health emergency worldwide. Since then, epidemiological and pathogenesis research has strengthened the evidence of this link.1 ,2 The relative risk of congenital ZIKV among children of pregnant women who acquire this acute infection is an important epidemiological parameter, particularly for family planning reasons in endemic countries. This prospective cohort study describes the incidence and extent of fetal abnormalities as well as maternal clinical presentations among pregnant …

Zika Virus Surveillance and Preparedness - New York City, 2015-2016.

Zika virus has rapidly spread through the World Health Organization's Region of the Americas since being identified in Brazil in early 2015. Transmitted primarily through the bite of infected Aedes species mosquitoes, Zika virus infection during pregnancy can cause spontaneous abortion and birth defects, including microcephaly (1,2). New York City (NYC) is home to a large number of persons who travel frequently to areas with active Zika virus transmission, including immigrants from these areas. In November 2015, the NYC Department of Health and Mental Hygiene (DOHMH) began developing and implementing plans for managing Zika virus and on February 1, 2016, activated its Incident Command System. During January 1-June 17, 2016, DOHMH coordinated diagnostic laboratory testing for 3,605 persons with travel-associated exposure, 182 (5.0%) of whom had confirmed Zika virus infection. Twenty (11.0%) confirmed patients were pregnant at the time of diagnosis. In addition, two cases of Zika virus-associated Guillain-Barré syndrome were diagnosed. DOHMH's response has focused on 1) identifying and diagnosing suspected cases; 2) educating the public and medical providers about Zika virus risks, transmission, and prevention strategies, particularly in areas with large populations of immigrants from areas with ongoing Zika virus transmission; 3) monitoring pregnant women with Zika virus infection and their fetuses and infants; 4) detecting local mosquito-borne transmission through both human and mosquito surveillance; and 5) modifying existing Culex mosquito control measures by targeting Aedes species of mosquitoes through the use of larvicides and adulticides.

Global spread of Zika virus epidemic: current knowledges and uncertainties

Zika virus (ZIKV) is an enveloped RNA virus that belongs to the Flaviviridae family. Although more than 60 years have passed since the discovery and first reported human cases of the virus, only a small number (< 10) of cases had been encountered in the literature until the last 10 years. Zika virus was known as a virus which caused sporadic infections and was confined to Africa and Asia along a narrow equatorial line. In 2007, however, the first major outbreak of ZIKV occurred in Yap Island (Micronesia), and so it was reported for the first time outside of Africa and Asia. Between the years of 2007 and 2014, ZIKV spreaded to island groups located in Southeast Asia and the Pacific Ocean, and in 2015-2016, it has spread to South and Central America and the Caribbean. Today, travel-related imported cases is still been reported in Europe, North America, and other countries in the Far East. According to the data from the World Health Organization and the Centers for Disease Control and Prevention, as of March 2016, ZIKV infections have already spread locally in more than 30 countries, and travel alerts have been issued for the countries where the virus is present. Zika virus infections are generally asymptomatic or may present with a moderate clinical picture (e.g. acute onset of fever, maculopapular rash, arthralgia, and nonpurulent conjunctivitis). Although no deaths were attributed to ZIKV infection over the past 60 years, as of November 2015, it has been suggested that three deaths in Brazil, including the death of a newborn with microcephaly, may be attributed to ZIKV infection. In addition, concurrent with outbreaks in 2013 in French Polynesia and in 2015 in Brazil, there have been significant rises reported in the incidence of some autoimmune and neurodevelopmental disorders, including Guillain-Barre syndrome and microcephaly; these reports have caused considerable international concern. There are many points that are still unclear about ZIKV, including: (1) intrauterine transmission risk, frequency, and effects of the infection on fetal development; (2) the probability of perinatal transmission and if so the possible risks; (3) association with autoimmune and neurological diseases, and presence of long-term sequelae risks after infection; (4) possible routes of transmission other than mosquito bites, such as sexual contact, blood transfusion, and other body fluids (saliva, semen, or urine); (5) presence of reservoir(s) and different mosquito vectors; (6) diagnostic difficulties including cross reactivity in serological tests and standardization of testing procedures; (7) severity of the infection in immunocompromised patients; and (8) the potential effectiveness of antiviral therapy or preventive vaccines. In this review, updated information and recommendations regarding ZIKV outbreaks and risks, and the epidemiology, diagnosis and characteristics of ZIKV infections, are summarized in light of the most recent literature.

Times to key events in Zika virus infection and implications for blood donation: a systematic review.

ObjectiveTo estimate the timing of key events in the natural history of Zika virus infection.MethodsIn February 2016, we searched PubMed, Scopus and the Web of Science for publications containing the term Zika. By pooling data, we estimated the incubation period, the time to seroconversion and the duration of viral shedding. We estimated the risk of Zika virus contaminated blood donations.FindingsWe identified 20 articles on 25 patients with Zika virus infection. The median incubation period for the infection was estimated to be 5.9 days (95% credible interval, CrI: 4.4–7.6), with 95% of people who developed symptoms doing so within 11.2 days (95% CrI: 7.6–18.0) after infection. On average, seroconversion occurred 9.1 days (95% CrI: 7.0–11.6) after infection. The virus was detectable in blood for 9.9 days (95% CrI: 6.9–21.4) on average. Without screening, the estimated risk that a blood donation would come from an infected individual increased by approximately 1 in 10 000 for every 1 per 100 000 person–days increase in the incidence of Zika virus infection. Symptom-based screening may reduce this rate by 7% (relative risk, RR: 0.93; 95% CrI: 0.89–0.99) and antibody screening, by 29% (RR: 0.71; 95% CrI: 0.28–0.88).ConclusionNeither symptom- nor antibody-based screening for Zika virus infection substantially reduced the risk that blood donations would be contaminated by the virus. Polymerase chain reaction testing should be considered for identifying blood safe for use in pregnant women in high-incidence areas.

The Emergence of Zika Virus as a Global Health Security Threat: A Review and a Consensus Statement of the INDUSEM Joint working Group (JWG).

The Zika virus (ZIKV), first discovered in 1947, has emerged as a global public health threat over the last decade, with the accelerated geographic spread of the virus noted during the last 5 years. The World Health Organization (WHO) predicts that millions of cases of ZIKV are likely to occur in the Americas during the next 12 months. These projections, in conjunction with suspected Zika-associated increase in newborn microcephaly cases, prompted WHO to declare public health emergency of international concern. ZIKV-associated illness is characterized by an incubation period of 3-12 days. Most patients remain asymptomatic (i.e., ~80%) after contracting the virus. When symptomatic, clinical presentation is usually mild and consists of a self-limiting febrile illness that lasts approximately 2-7 days. Among common clinical manifestations are fever, arthralgia, conjunctivitis, myalgia, headache, and maculopapular rash. Hospitalization and complication rates are low, with fatalities being extremely rare. Newborn microcephaly, the most devastating and insidious complication associated with the ZIKV, has been described in the offspring of women who became infected while pregnant. Much remains to be elucidated about the timing of ZIKV infection in the context of the temporal progression of pregnancy, the corresponding in utero fetal development stage(s), and the risk of microcephaly. Without further knowledge of the pathophysiology involved, the true risk of ZIKV to the unborn remains difficult to quantify and remediate. Accurate, portable, and inexpensive point-of-care testing is required to better identify cases and manage the current and future outbreaks of ZIKV, including optimization of preventive approaches and the identification of more effective risk reduction strategies. In addition, much more work needs to be done to produce an effective vaccine. Given the rapid geographic spread of ZIKV in recent years, a coordinated local, regional, and global effort is needed to generate sufficient resources and political traction to effectively halt and contain further expansion of the current outbreak.