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Critical component of global ZIKA virus control strategies.

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Presentation on theme: "Critical component of global ZIKA virus control strategies."— Presentation transcript:

1 Critical component of global ZIKA virus control strategies.
Dmitri Popov. PhD, Radiobiology. MD (Russia) Advanced Medical Technology and Systems Inc. Canada.

2 Global ZIKA virus control strategies.
 (ZIKV) is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus.

3 Global ZIKA virus control strategies.
EBOLA YELLOW FEVER WEST NILE VIRUS DENGUE FEVER

4 Global ZIKA virus control strategies.
The Zika virus belongs to Flaviviridae and the genus Flavivirus, and is thus related to the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Like other flaviviruses, Zika virus is enveloped and icosahedral and has a nonsegmented, single-stranded, positive-sense RNA genome. It is most closely related to the Spondweni virus and is one of the two viruses in the Spondweni virus clade. There are two lineages of the Zika virus: the African lineage, and the Asian lineage.  Phylogenetic studies indicate that the virus spreading in the Americas is most closely related to the Asian strain, which circulated in French Polynesia during the 2013 outbreak. The complete genome sequence of the Zika virus has been published

5 Global ZIKA virus control strategies.
The vertebrate hosts of the virus were primarily monkeys in a so- called enzootic mosquito-monkey-mosquito cycle, with only occasional transmission to humans Before the current pandemic began in 2007, Zika virus "rarely caused recognized 'spillover' infections in humans, even in highly enzootic areas" Infrequently, other arboviruses have become established as a human disease though, and spread in a mosquito–human–mosquito cycle, like the yellow fever virus and the dengue fever virus (both flaviruses), and the chikungunya virus (a togavirus)

6 Global ZIKA virus control strategies.
The Zika virus is transmitted by daytime-active mosquitoes as its vector. It is primarily transmitted by Aedes aegypti, but has been isolated from a number of arboreal mosquito species in the Aedes genus, such as A. africanus, A. apicoargenteus, A. furcifer, A. hensilli, A. luteocephalus and A. vittatus with an extrinsic incubation period in mosquitoes of about 10 days

7 Global ZIKA virus control strategies.
The Zika virus has been detected in many more species of Aedes, along with Anopheles coustani, Mansonia uniformis, and Culex perfuscus, although this alone does not incriminate them as a vector. Transmission by A. albopictus, the tiger mosquito, was reported from a 2007 urban outbreak in Gabon where it had newly invaded the country and become the primary vector for the concomitant chikungunya and dengue virus outbreaks. There is concern for autochthonous infections in urban areas of European countries infested by A. albopictusbecause the first two cases of laboratory confirmed Zika virus infections imported into Italy were reported from viremic travelers returning from French Polynesia.

8 Global ZIKA virus control strategies.
The potential societal risk of Zika virus can be delimited by the distribution of the mosquito species that transmit it. The global distribution of the most cited carrier of Zika virus, A. aegypti, is expanding due to global trade and travel.  A. aegypti distribution is now the most extensive ever recorded – across all continents including North America and even the European periphery (Madeira, the Netherlands, and the northeastern Black Sea coast)

9 Global ZIKA virus control strategies.
Common methods:     – Indoor residual spraying (IRS)     – Insecticide treated nets (ITNs)     – Personal protection     – Larvar source management (LSM)

10 Global ZIKA virus control strategies.
Many malaria vectors are considered "endophilic"; that is, the mosquito vectors rest inside houses after taking a blood meal. These mosquitoes are particularly susceptible to control through indoor residual spraying (IRS). What Is Indoor Residual Spraying? As its name implies, IRS involves coating the walls and other surfaces of a house with a residual insecticide. For several months, the insecticide will kill mosquitoes and other insects that come in contact with these surfaces. IRS does not directly prevent people from being bitten by mosquitoes. Rather, it usually kills mosquitoes after they have fed if they come to rest on the sprayed surface. IRS thus prevents transmission of infection to other persons. To be effective, IRS must be applied to a very high proportion of households in an area (usually >80%).

11 Global ZIKA virus control strategies.
An insecticide is a substance used to kill insects.  They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in agricultural 20th century's productivity.  Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; some concentrate along the food chain. IRS with DDT was the primary malaria control method used during the Global Malaria Eradication Campaign ( ). The campaign did not achieve its stated objective but it did eliminate malaria from several areas and sharply reduced the burden of malaria disease in others. IRS with DDT was the primary malaria control method used during the Global Malaria Eradication Campaign ( ). The campaign did not achieve its stated objective but it did eliminate malaria from several areas and sharply reduced the burden of malaria disease in others.

12 Global ZIKA virus control strategies.
Concern over the environmental impact of DDT led to the introduction of other, more expensive insecticides. As the eradication campaign wore on, the responsibility for maintaining it was shifted to endemic countries that were not able to shoulder the financial burden. The campaign collapsed and in many areas, malaria soon returned to pre-campaign levels.

13 Global ZIKA virus control strategies.
As a result of the cost of IRS, the negative publicity due to the failure of the Malaria Eradication Campaign, and environmental concerns about residual insecticides, IRS programs were largely disbanded other than in a few countries with resources to continue them. However, the recent success of IRS in reducing malaria cases in South Africa by more than 80% has revived interest in this malaria prevention tool.

14 Global ZIKA virus control strategies.
Insecticide-treated bed nets (ITNs) are a form of personal protection that has been shown to reduce malaria illness, severe disease, and death due to malaria in endemic regions. In community-wide trials in several African settings, ITNs have been shown to reduce the death of children under 5 years from all causes by about 20%.

15 Global ZIKA virus control strategies.
Malaria Eradication Campaign principals should be used for ZIKA Eradication Campaign. However, environmental concerns about residual insecticides remain seriously and may be dangerous for human organism.

16 Global ZIKA virus control strategies.
Novel method for Global ZIKA virus control strategies introduced as a part of effective larval control. Anopheles , one of the primary vectors , breeds in numerous small pools of water that form due to rainfall. The larvae develop within a few days, escaping their aquatic environment before it dries out. It is difficult, if not impossible, to predict when and where the breeding sites will form, and to find and treat them before the adults emerge. Therefore, larval mosquito control for the prevention of malaria in Africa has not been attempted on a large scale. It may, however, be appropriate for specific settings such as urban environments or desert fringe areas where habitats are more stable and predictable. WHO recently recommended larval control as appropriate for areas where the larval habitats are "few, fixed, and findable.“ ml

17 Global ZIKA virus control strategies.
Chemical Larviciding For some mosquito species, habitat elimination is not possible. For these species, chemical insecticides can be applied directly to the larval habitats. Other methods, which are less disruptive to the environment, are usually preferred: Oils may be applied to the water surface, suffocating the larvae and pupae. Most oils in use today are rapidly biodegraded. Toxins from the bacterium Bacillus thuringiensis var. israelensis (Bti) can be applied in the same way as chemical insecticides. They are very specific, affecting only mosquitoes, black flies, and midges. Insect growth regulators such as methroprene are specific to mosquitoes and can be applied in the same way as chemical insecticides. ml

18 Global ZIKA virus control strategies.
Biological Control Potential biological control agents, such as fungi (e.g., Laegenidium giganteum) or mermithid nematodes (e.g., Romanomermis culicivorax), parasitize and kill larval mosquitoes but they are not efficient for mosquito control and are not widely used. Likewise, mosquito fish (including Gambusia affinis) have largely been ineffective except in a few studies.

19 Global ZIKA virus control strategies.
Fogging or Area Spraying Fogging or area spraying is primarily reserved for emergency situations such as epidemics. Fogging has not been shown to be effective in any malaria-endemic areas. Fogging and area sprays must be properly timed to coincide with the time of peak adult mosquito activity, because resting mosquitoes are often found in areas that are difficult for the insecticide to reach (e.g., under leaves, in small crevices). In addition, fogging and area spraying will have to be repeatedly applied to have an impact, and it can easily become too costly to maintain or result in the overuse of insecticides. .html

20 Global ZIKA virus control strategies.
Personal Protection Measures Personal protection measures include the use of window screens, ITNs, and repellents (such as DEET) and wearing light-colored clothes, long pants, and long-sleeved shirts. Well-constructed houses with window screens are effective for preventing biting by mosquitoes that bite indoors and may have contributed to the elimination of malaria from the United States and Europe. Recent evidence suggests that repellents may be effective in reducing malaria transmission and may be appropriate for areas where mosquitoes bite outdoors or early in the evening when people are not using ITNs. However, while repellents are recommended for travelers to malaria-endemic areas, further work to develop repellent formulations that are easily deployed in endemic countries is needed. .html

21 Global ZIKA virus control strategies.
Sterile Male Release Introducing sterile male mosuitoes into an area has been successfully applied in several small-scale areas. However, the need for large numbers of mosquitoes for release makes this approach impractical for most areas. Genetic Modification of Malaria Vectors Genetic modification aims to develop mosquitoes that are not susceptible to the parasite. This approach is still many years from application in field settings.

22 Global ZIKA virus control strategies.
Chlorine-containing agents are the most commonly used disinfectants in medical facilities, as they possess a wide range of anti-microbe activity and swift action ability. Decontamination effect being the same, preference shall be given to disinfectants that are cheap, safe for medical stuff and have no harmful influence on the environment. Novel method use Chlorine-containing agents against ZIKA virus can be very effective for larval control .

23 Global ZIKA virus control strategies.
Of all inorganic chlorine-containing disinfectants the cheapest ones are sodium Hypochlorite and electrochemically activated Anolyte solution, produced by sodium chloride electrolysis. Disinfecting effectiveness of Anolyte is higher than that of calcium hypochlorite , and even in small concentrations it completely destroys microbes and viruses . Anolyte with active chlorine concentration of 300mg/l causes irreversible damage to the membrane of most microbes already in one minute and is recommended for wide implementation in clinical and preventive medical facilities for disinfecting and sterilisation purposes.

24 Global ZIKA virus control strategies.
Sodium hypochlorite is a chemical compound with the formula NaClO. It is composed of a sodium cation  (Na+) and a hypochlorite anion (ClO−); it may also be viewed as the sodium salt of hypochlorous acid.

25 Global ZIKA virus control strategies.
Equipment: Mobile and Industrial. Cost effective, Simple, Effective Therapy.

26 Global ZIKA virus control strategies.
Sodium hypochlorite very effective for sterilization against viruses and effective method for virus ZIKA control. OXIDIZERS – Sodium Hypochlorite. Hydrogen peroxide is a chemical compound with the formula H 2O 2. In its pure form, it is a colourless liquid, slightly more viscousthan water; however, for safety reasons it is normally used as an aqueous solution. Hydrogen peroxide is the simplest peroxide (a compound with an oxygen– oxygen single bond) and finds use as a strong oxidizer, bleaching agent and disinfectant. Concentrated hydrogen peroxide, or "high-test peroxide", is a reactive oxygen species and has been used as a propellant in rocketry.

27 Global ZIKA virus control strategies.
Hydrogen peroxide can be used for the sterilization of various surfaces including surgical tools and may be deployed as a vapour (VHP) for room sterilization. H2O2 demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. In general, greater activity is seen against gram-positive than gram-negative bacteria; however, the presence of catalase or other peroxidases in these organisms can increase tolerance in the presence of lower concentrations. Higher concentrations of H2O2 (10 to 30%) and longer contact times are required for sporicidal activity.

28 Global ZIKA virus control strategies.
Hydrogen peroxide is seen as an environmentally safe alternative to chlorine-based bleaches, as it degrades to form oxygen and water and it is generally recognized as safe as an antimicrobial agent by the U.S. Food and Drug Administration (FDA). Surgical use can lead to gas embolism formation. Despite this it is still used for wound treatment in many developing countries

29 Global ZIKA virus control strategies.
Practitioners of alternative medicine have advocated the use of hydrogen peroxide for the treatment of various conditions, including emphysema, influenza, AIDS and in particularcancer.  The practice calls for the daily consumption of hydrogen peroxide, either orally or by injection and is, in general, based around two precepts. First, that hydrogen peroxide is naturally produced by the body to combat infection; and second, that human pathogens (including cancer: See Warburg hypothesis) are anaerobic and cannot survive in oxygen-rich environments. The ingestion or injection of hydrogen peroxide is therefore believed to kill disease by mimicking the immune response in addition to increasing levels of oxygen within the body. This makes it similar to other oxygen-based therapies, such as ozone therapy and hyperbaric oxygen therapy.

30 Global ZIKA virus control strategies.
Historically hydrogen peroxide was used for disinfecting wounds, partly because of its low cost and prompt availability compared to other antiseptics. It is now thought to slow healing and lead to scarring because it destroys newly formed skin cells. Only a very low concentration of H2O2 can induce healing, and only if not repeatedly applied.


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