Zika-Overview.Pdf

1 As I’m sure most of you have heard, Zika is an “arboviral”, or mosquito‐borne disease spread primary through the bite of an Aedes species mosquito infected with Zika virus. I’m going to spend the first part of this session providing a background on Zika to make sure that we all have a shared baseline understanding of the disease. You’ll hear about the history of the disease, the current Zika outbreak, and information about transmission, symptoms and effects of Zika. Please keep in mind that while we’ve learned a lot about Zika in the past year, there is still a lot the public health and scientific community doesn’t know. We continue to learn more every day about this disease and new guidelines, information and recommendations are released all the time. The best place for current, up to date information on Zika is our website (azhealth.gov/zika) or the CDC website (cdc.gov/zika) 2 Zika virus first identified in Zika forest in Uganda in a rhesus monkey; testing of mosquitoes identified the vector to be Aedes africanus. 3 Zika was first discovered in a monkey in Zika Forest in Uganda in 1947, where it got it’s name. From 1947 to 2006, numerous studies were done to identify where Zika might be present, and identified evidence of the virus in multiple African and Asian countries. Despite the wide geographic range, only 14 human cases were documented. 4 The first large Zika virus outbreak outside of Africa and Asia occurred in Yap, Micronesia in 2007, shown by the circle and arrow on the map. Zika was estimated to have infected almost 75% of the population of the island; however, only about 20% of infected people experienced symptoms. 5 From 2013‐2014, Zika virus continued to spread in the Pacific Islands, causing outbreaks in French Polynesia, New Caledonia, Cook Islands, Vanuatu, Fiji, the Solomon Islands, and Easter Island 6 Zika’s first introduction to the Americas occurred about a year ago, when the virus circulation was identified in May in northeastern Brazil. From May to July, an increase in Guillain Barre syndrome, an illness that causes nerve damage and paralysis, was identified in some of the same areas where the virus was circulating. By December of last year, local transmission of Zika had been identified in over 18 Brazilian states. And then, Zika came to the Americas, where it was 1st ID’d back in 2015 in NE Brazil. 7 8 This map from CDC depicts the countries with active Zika transmission as of Dec 29, 2016. There are currently over 55 countries and territories in the Americas, Pacific Islands, and Cape Verde in Africa are experiencing active transmission of Zika virus. That means the Zika is spreading locally within areas of these countries. https://www.cdc.gov/zika/geo/active‐countries.html 9 Imported, or travel associated cases of Zika occur when someone gets infected with Zika while away from home. For example, if someone traveled to Brazil, got bit by a mosquito infected with Zika, and then came back to the U.S. and was diagnosed with Zika, she would considered to be an imported or travel‐associated case of Zika. There have been travel‐associated cases of Zika in the U.S. 10 Local transmission of Zika virus occurs when a person who has not traveled gets sick where they live, work, or play. Areas that have local transmission of Zika virus are considered to be areas of active transmission. There has been no local transmission of Zika to date in Arizona but there has been in some areas of FL. 11 https://www.cdc.gov/zika/geo/united‐states.html 12 https://www.cdc.gov/zika/intheus/florida‐maps.html 13 Brownsville, TX. Yellow shows areas where pregnant women should consider postponing travel. 14 (GBS –a rare illness that causes nerve damage and paralysis and can occur after an infection). https://www.cdc.gov/zika/geo/united‐states.html 15 16 There are ways that Zika is transmitted. 1. The 1° route is Through mosquito bites –an Aedes mosquito bites someone infected with Zika virus, the Aedes mosquito becomes infected with Zika virus, the infected Aedes mosquito bites healthy people and infects them with Zika virus 2. From a pregnant woman to her fetus 3. Through unprotected sexual contact 4. Through blood transfusions 17 In mosquitoes, the incubation period, or time between when a mosquito bites someone infected with Zika and when that mosquito is able to transmit Zika to another person, is about 10 days. In other words, if you have Zika and a mosquito bites you and becomes infected with Zika virus, that mosquito won’t infect anyone with Zika for about 10 days. 18 In humans, the incubation period, or time between the bite from an infected mosquito and symptom onset, is about 1 week. So –if we were somewhere Zika is circulating, and were bitten by a mosquito today, we might expect to start experiencing symptoms next week or early the following week. 19 Most people who are infected with Zika won’t know they have it because only about 1 in 5 people develop symptoms. 20 The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis or red eyes. Other symptoms include muscle pain and headaches. Almost all people (90+%) who have Zika symptoms will experience a rash. The rash is usually itchy and typically a fully body rash. Symptoms of Zika re very similar to other mosquito‐borne diseases like dengue and chikungunya. 21 22 According to WHO, as of May 11th, 1,354 cases of microcephaly or CNS malformation potentially associated with Zika infection have been reported from 9 countries, territories, or areas. In addition to microcephaly, other problems have been detected among fetuses and infants infected with Zika virus before birth, such as vision and hearing issues 23 There are currently groups working on vaccines for Zika, but the timeline for development is currently unknown. 24 In terms of precautions people should take to protect themselves from the threat of Zika – the most important thing is to protect yourself from mosquito bites. During the first week of illness, Zika virus can be found in blood for about a week. If a mosquito bites the person, it can become infected and can pass the infection to others. It is also important for someone infected with Zika to avoid unprotected sex: Zika virus can be sexually transmitted In the known cases of likely sexual transmission, the individuals had been symptomatic (but the virus can be transmitted before, during, and after symptoms develop) The virus can be present in semen longer than in blood. We do not know how long the virus can stay in the semen of men who have had Zika – it has been found 62 days after – but unclear if still viable –in that will it cause and infection or is it just dead virus detected? We do not know if sexual transmission of Zika virus poses a different risk of birth defects than mosquito‐borne transmission. 25 There are many different kinds of mosquitos. Zika is known to be spread by Aedes species mosquitos, including Aedes aegypti and Aedes albopictus. Here in Arizona, our main threat is from Aedes aegypti. This is the same kind of mosquito that can spread dengue and chikungunya viruses. 26 Aedes aegypti are aggressive daytime biters that prefer to feed on humans. This is different than the Culex species of mosquitos, which will feed on animals and humans and more regularly bite at dawn and dusk. Because Aedes aegypti prefer to feed on humans, they have adapted to live around humans and their homes, and thus, do not travel very far from where they are born. They are quite domesticated 27 This map shows CDC’s best estimates about the potential range of Aedes aegypti mosquitos in the U.S., taking into account the mosquito’s preferred habitat and where Aedes aegypti has previously been found. 28 Based on mosquito surveillance efforts by local health departments in Arizona, we know that over the past decade, Aedes aegypti mosquitos have primarily been found in the Central and Southern parts of Arizona. Continued surveillance efforts are underway to identify specific locations where these mosquitos may be present, and how abundant they might be. 29 30 31 32.

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