Robert W. Malone; Jane Homan; Michael V. Callahan; Jill Glasspool-Malone; Lambodhar Damodaran; Adriano De Bernardi Schneider; Rebecca Zimler; James Talton; Ronald R. Cobb; Ivan Ruzic; Julie Smith-Gagen; Daniel Janies; James Wilson

“ The greatest potential for new introduction and establishment of local autochthonous transmission appears to be a combination of viremic human importation by ground, sea and air, and/or cargo-associated transport of infected mosquitos and larvae by trucks, ships and airplanes. Therefore, countering human and freight-based introduction appears to be the best countermeasure strategy available for delaying the spread of the Zika virus into new regions of the Americas. ”

“ This suggests that, with the current Zika outbreak, the virus may spread so efficiently that by the time a vaccine becomes available to test in human clinical trials, identifying large naïve at-risk populations may be an obstacle to demonstrating efficacy.
Zika virus evolution and spread is constrained by both human and insect hosts, and this creates an opportunity to develop countermeasure strategies focusing on either or both. The interaction between pathogen and host biology will impact the incidence, prevalence and eventual distribution of the virus. ”

“ In many ways Zika presents a much more complex challenge than Ebola, and it may impact more lives. It is vector borne, and therefore its range of transmission will be determined by vector ecosystem. Limiting movement or contact of people cannot significantly contain it. Acute infection may be unapparent, so patients cannot be quarantined. Zika-related disease has its most devastating effects on the unborn fetus with a delay to diagnosis. The transplacental pathology is not understood. The occurrence of GBS suggests that Zika virus associated disease has an autoimmune component. ”

“ Uncertainties about Zika virus transmission abound. The degree to which humans, non-human primates, or other animals can amplify and transmit the virus to insect vectors is poorly understood. The typical range and types of insect vectors observed in the past may not be predictive for the virus now circulating in the Americas. Infectivity of the circulating strain, viremia levels, duration, and risk of occult persistence are not yet understood. ”

“ Opportunities and strategies for Zika medical management and countermeasure development will benefit from answers to key questions concerning the virology and immunology of Zika infection in the human host. A better understanding of natural immune responses and viral infection may clarify the potential role of Zika in eliciting GBS or microcephaly. Targeted identification and design of antivirals, neutralizing antibody preparations and immunotherapeutics still require understanding of the underlying biology. ”

“ Based on prior murine studies involving Zika virus inoculation in mouse brain [ [99] ] , autophagy of Zika virus has been postulated as playing a key role in the pathogenesis of Zika-associated primary microcephaly [ [100] ] .
The infection and host response cascade triggered by initial infection with Zika virus has yet to be characterized. Dengue infection in humans may provide a model until further information becomes available. In the case of dengue, the infection then spreads to both lymphatic and non-lymphatic tissues; fever, arthralgia and myalgia ensue. ”

“ Evidence supporting avian infection by Zika virus has been reported [ [16] ] , but the prevalence in birds and potential of transmission from avian species to humans via insect intermediates has not been studied. West Nile virus was rapidly spread throughout North America by birds. Transoceanic movements of arboviruses in insects has been reported [ [69] ] . However, the relative absence of Zika along the western coast of South America argues against wind or avian-borne introduction across the Andes into northeastern Brazil from Polynesia or Easter Island. ”

“ To optimize MCM development, the link between infectious cause and clinical effect must be clearly established. However, as evidence has accumulated, skepticism about a causal link between Zika spread and primary microcephaly incidence has given way to growing acceptance that Zika virus infection during the first and second trimester may be a major contributing factor to the surge in microcephaly. The possible increase in GBS incidence, associated morbidity and mortality, and potential association of these disease symptoms with Zika is not as solid. ”

“ The CD8+ T cell responses to dengue infection are primarily directed to nonstructural protein epitopes including NS3 and NS5. Human infection by dengue provides one of the most classic examples of antibody dependent enhancement of disease by pre-existing non-neutralizing antibody, resulting in dengue hemorrhagic fever [ [101] , [102] ] . The potential role of antibody dependent enhancement (ADE) of Zika infection and disease has not been examined.
The duration of viremia, infectivity, and persistence of Zika virus, is not known for either post-partum or intrauterine infection. ”

“ As Zika adapts to new niches in the Americas, the roles played by humans and non-human primates, other animals and arthropods as primary and intermediate hosts must be understood. Factors which will influence the rate of spread include availability of vector species, temperature and humidity available to support transmissibility, and high mosquito to human contact rates. Similar to dengue and chikungunya, Aedes sp. (Ae. aegypti and Ae. albopictus) appear to be the leading candidate Zika vectors in the outbreak. Potential involvement of other insect vectors including Culex sp. ”

“ Death after Zika virus infection of an otherwise healthy patient with sickle cell disease has also been reported, indicating increased risk to otherwise medically compromised individuals [ [23] ] . The more severe Zika disease symptoms were not observed during the 2007 Yap Island, Micronesia, Zika outbreak, although approximately 5,000 people were infected [ [24] ] . Zika virus infection and disease is now a reportable illness in the United States, and as of February 2016, has spread to the countries and territories summarized in Table 1. ”

“ The Pan American Health Organization (PAHO) predicts that Zika virus will continue to spread and eventually reach all countries and territories in the Americas with endemic Aedes mosquitoes. This paper reviews the status of the Zika virus outbreak, including medical countermeasure options, with a focus on how the epidemiology, insect vectors, neuropathology, virology and immunology inform options and strategies available for medical countermeasure development and deployment. ”

“ Abstract Introduction Reports of high rates of primary microcephaly and Guillain–Barré syndrome associated with Zika virus infection in French Polynesia and Brazil have raised concerns that the virus circulating in these regions is a rapidly developing neuropathic, teratogenic, emerging infectious public health threat. There are no licensed medical countermeasures (vaccines, therapies or preventive drugs) available for Zika virus infection and disease. ”

“ Pregnant women are typically the last “special population” to be clinically tested when developing a MCM, but this outbreak represents a special case where the fetus is apparently at highest risk.
Development of a general use prophylactic vaccine for Zika virus-induced disease will require considerable time and careful evaluation of safety, effectiveness, and risk/benefit ratio for the population at large. ”

“ For example, developing, testing and deploying a new vaccine may be feasible for endemic pathogens or slowly moving epidemics, but may not be practical for a rapidly moving infectious disease outbreak. Until the pathogenesis of the disease, nature of vectors and mechanisms of spread are understood, caution must be exercised in making assumptions in the design of MCM.
Flaviviruses can appear significantly more pathogenic when introduced into new niches and populations, but as a new virus becomes established, herd immunity effects often attenuate apparent virulence. ”

“ In the case of many arboviruses, mosquito salivary gland products enhance viral infectivity and replication. Zika infection of the recipient host requires viral envelope protein binding and particle uptake into susceptible cells, is mediated by specific receptors which include DC-SIGN, AXL, Tyro3, and TIM-1, and triggers transcriptional activation of Toll-like receptor 3 (TLR3) , RIG-I, MDA5, interferon stimulated genes including OAS2, ISG15, and MX1, and beta interferon [ [97] ] . Primarily infected cells include skin fibroblasts, epidermal keratinocytes, and skin dendritic cells. ”

“ To summarize these events and to help guide assessment of genetic and immunologic differences between historic and current Zika virus populations, we performed preliminary phylogeographic analyses of available molecular sequence data and metadata (place and time of isolation) from the viruses to connect these incidents via shared ancestry of the sequences. Based on data released as of January 18, 2016 we have focused on two genes to reconstruct the spread and evolution of Zika from Africa to Southeast Asia to the South Pacific and to South America ”

“ These include human networking, reporting signature pattern recognition and forecasting, social media tracking and bioinformatics, including geospatial analysis of isolates and immunoinformatics. The West African Ebola virus outbreak of 2014–2015 revealed serious deficiencies in global surveillance, threat identification and management capabilities for infectious disease epidemics. The various lessons-learned exercises which followed may help guide a more effective response to the threats associated with the current outbreak. ”

“ Further study of the role of transplacental immunoglobulin in Zika teratology will be needed.
MAbs which have been appropriately engineered and de-risked have the potential to protect against Zika infection, but a mAb product must have high potency if it is to provide an adequate number of doses at reasonable cost. For example, the adult dose of ZMapp that may reduce the spread of Ebola within the body requires nearly 200 x 10ml vials at 100mg/ml of three antibodies that recognize distinct epitopes of the Ebola Zaire glycoprotein. ”

“ Countering transportation-based introduction is the best immediate strategy available for delaying the spread. Options include more rigorous cargo fumigation at ports and border crossing points, use of larvicides and insecticides, and monitoring ground, sea, and air travel from infected areas. Seaports and the US/Mexico border are the most critical points for reducing the risk of large-scale vector borne viral distribution into the United States and Canada. ”

“ Physicians and their patients are asking for practical information to guide routine decisions, and are expressing frustration about public health communication and availability of the clinical tests required to manage important reproductive health decisions. ”

“ Cardoso, T & Herida, M (2014) , Current Zika virus epidemiology and recent epidemics, vol. 44, pp. 302–7, 25001879, pmid:25001879, DOI 10.1016/j.medmal.2014.04.008 1 2 Rapid risk assessment: Microcephaly in Brazil potentially linked to the Zika virus epidemic, Stockholm: ECDC, 2015, ↑ , ↑ Moore, DL ”

“ Tsai, WL & Chen, JJ (2015) , Hydroxychloroquine-inhibited dengue virus is associated with host defense machinery, vol. 35, pp. 143–56, 25321315, pmid:25321315, DOI 10.1089/jir.2014.0038 ↑ Sciascia, S; Branch, DW; Levy, RA; Middeldorp, S; Pavord, S & Roccatello, D (2015) , The efficacy of hydroxychloroquine in altering pregnancy outcome in women with antiphospholipid antibodies. Evidence and clinical judgment, vol. 115, 26421409 SciasciaSBranchDWLevyRAMiddeldorpSPavordSRoccatelloDet aldoi: 10.1160/TH15-06-0491, pmid:26421409 ↑ Qiao, S; Tao, S ”