Zika is a mosquito-borne virus that in its urban cycle transmits between Aedes species mosquitoes and humans. Aedes can live in close contact with Humans. They preferentially feed on human blood. They can live in our house and leave to lay their eggs in standing water outside human residences. They are now understood to be other less common ways that Zika can be transmitted, vertically from mother to child during pregnancy, through sexual contact, and transfusion transmission.
So Zika historically is an African virus that was first isolated in Uganda in 1947. And then it caused sporadic and poorly-described human disease starting, the first human disease was recognized in west Africa in the 1960s. So from the ’60s until about 10 years ago, Zika caused small and focal outbreaks in Africa and Asia. But as you know starting in 2014, Zika was introduced into the Americas.
The virus has been introduced into 50+ new countries and territories in the Americas. So what happens when there is a Zika case that’s reported to CDPH, the Mosquito and Vector Control districts go out to the case’s residence, try to kill adult mosquitoes in the area and then remove the standing water containers to eliminate breeding sites.
Which mosquitoes are responsible for transmitting Zika? And this is epidemiologically-relevant because if you want to target vector control without a licensed vaccine, you have to know which species are transmitting the virus. After all, mosquitoes have different ecologies and different feeding behaviors and they also have different distributions.
One reason why it’s important to know whether North American Culex can transmit Zika is you’ll notice that their range extends much, especially for Culex pipiens much further north than the Aedes species. So when that press release came out, a lot of the Mosquito and Vector Control districts around the United States expressed a lot of concern in understanding whether there was a big host switch. So how do we know which mosquito species are competent vectors? As you know there are hundreds of different mosquito species around the world. And to the naked eye, they look very similar, but they are very different. And they’re not all capable of transmitting human and animal pathogens.
So there are four criteria that a mosquito species has to fulfill to be considered a competent vector. They have to be abundant, they have to survive long enough to transmit, they have to feed frequently on competent vertebrate hosts. So these are criteria that we can establish in field entomological surveys.
The fourth criterion is the one that researchers have been looking at which is that you can show in a laboratory setting that certain species are capable of transmitting the virus. This is a cross-section of a mosquito. Researchers ingest an infectious blood meal that goes into the mosquito stomach or the midgut. The virus has to infect the midgut epithelium and then disseminate onto the other side of the midgut into the open circulatory cavity of the mosquito and be in the liquid that bathes it, which is called the demolish. So that then it can infect the secondary target organs which in the case of a transition-competent mosquito would include the salivary glands. So that the virus will then be excreted into the saliva so that when the mosquito refeeds, she transmits it into a new host.
This period takes a certain amount of time in a mosquito. So the way we do this experimentally is we take viremic mice that have been inoculated with Zika, and then are at their peak of viremia. We anesthetize them and then we present them to cohorts of female mosquitoes of the different species that we’re interested in studying.
Then after the period that the virus moves through the mosquito body, we tear off the legs and the wings of the still-living mosquito and we inject the proboscis into a tube filled with liquid which stimulates salivation. So we’re essentially milking the mosquitoes. If we detect the Zika virus or RNA in the expectorant, we know that that species is transmission-competent.
There’s another interesting phenomenon that’s been observed which is that within a given mosquito species, there can be regional variations or geographic variations in the capacity for those mosquitoes to transmit.
So there’s also been an interest in understanding whether Aedes aegypti from one place is also as transmission-competent as Aedes aegypti from another place. This data synthesizes the field of vector transmission studies where you can see groups from various places have been collecting their local mosquitoes and then looking at the capacity of them to transmit.
Lab data confirms that Aedes aegypti from all over the world are capable of transmitting Zika as is Aedes albopictus from the one study in Germany. Looking at the Culex data, it is almost uniform that not a single mosquito was tested and unlike invertebrate studies, we have lots more mosquitoes, so our cohort sizes are often in 50 to 100. We can say out of the thousands of Culex that have been tested from around the world, they’re not transmission-competent, save for this one outlier study which I think could be potentially interesting.
So barring any methodological issues with the paper, this could be a case that there is something different about these Chinese Culex quinquefasciatus mosquitoes that enables them to transmit Zika. Alternately there could be something different about the Zika virus strain that was used in that Chinese study. It was an Asian lineage genotype virus, the same that’s circuiting in the Americas that was in a traveler returning to China. But overall, the burden of evidence shows that Zika has not shifted to use Culex mosquitoes as vectors.
Another question that scientists have been interested in, as you know there’s been a lot of curiosity as to what factors have promoted the emergence of Zika. On the mosquito side, one question is whether the spread of the Asian lineage virus has been promoted by enhanced transmissibility by the primary vector in most places, Aedes aegypti.
To address this question, Scientists took an ancestral virus in the Asian lineage from 1966 in Malaysia that was the low passage and compared that in the vector-competent experiment, side-by-side with the contemporary Puerto Rican strain.
They used an Uganda strain from 1947 and a Senegalese strain from 1997. Data shows 40% and 60% of the mosquitoes that fed on the mouse were capable of transmitting between seven and 14 days post-feed, but there was no significant strain-specific difference. This refutes the idea that the emerging Asian lineage Zika is more transmissible than its Asian lineage progenitor strain. So in fact the emerging viruses are doing worse in aegyptia than the African lineage strains.
So the reasons for having animal models of infectious diseases, We think are pretty obvious, but we feel that the placental and neurological development of nonhuman primates is closer to humans than that of mice. So even in the last year and a half, the Zika non-human primate field has rapidly advanced and globally know a lot already. Please find latest development from WHO on ZIKA virus here
Andromeda: Andromeda galaxy appears inside Andromeda constellation. Andromeda galaxy is the nearest galaxy to our milky way galaxy. It has total of 72 stars and 12 planets.
Antlia: Antlia constellation appears at the southern celestial hemisphere. It consists of approximately 13 stars including 2 planets. The brightest galaxy in Antlia is NC2997
Apus: it is a tiny constellation in southern sky. Apus has a total of 16 starts with 2 planet stars. Orange giant Alpha Apodis is the brightest star in this constellation.
Aquarius: It is a prominent constellation as it symbolizes one of the zodiac Sign. It has over 100 stars, out of the 12 are planet that could be possible exoplanets. The brightest star in this constellation is Beta Aquarii. Constellation can be easily seen by naked eyes.
Aquila: Aquila appears on celestial equator plane and it has a shape of bird eagle. There are 10 primary stars, 65 bayers stars and stars with planets. protoplanetary nebula IRAS 19024+0044 is present in Aquila.
Ara: Ara star constellation appears on the southern hemisphere. It has 8 main stars, 17 bayers and 7 planet stars. Beta Arae is the brightest start in Ara constellation and can be seen by naked eye.
Aries: Aries is one of the zodiac Sign in astrology and prominent constellation. NGC772 is a spiral galaxy can be seen inside Aries constellation with the use of telescope. It contains 86 stars within its constellation.
Auriga: Auriga constellation appears at the north of celestial equator. It has area of 657 square degree. It has close to 85 stars including 7 exoplanets. The shiniest start in Auriga constellation is Alpha Aurigae and it is estimated to be 43 light years away. NBC1893 is largest open cluster in Auriga constellation.
Bootes: Bootes constellation appears at the northern sky. It has an area of 907 square degree. 7th and 15 are the brightest stars. Brightest star in Bootes star constellations is Arcturus. With the diameter of 11 million miles, Arcturus is 23 times bigger than our sun and 36.7 light years away from earth.
Caelum: Caelum is located usually at southern sky. It has an area of 125 square degree. Seyfert galaxy is part of Caelum constellation which is also referred as HE0450-2958. It 81st in size out of 88 start constellations in our universe. It has 4 bright stars.
Camelopardalis: Camelopardalis constellation has a giraffe resembling figure.it has area of 757 square degree and 2nd and 8th are the brightest star in Camelopardalis constellation.
Cancer: Cancer is one of the 12 zodiac signs and one of prominent constellation. It has an area of 506 degree square and have 5 bright stars that can be seen with naked eye. Beta Cancri is the brightest star in cancer constellation. It resembles as upside down fork and has most probable super earth with earth like temperature.
Canes Venatici: it is one the smelled star constellation in the northern hemisphere. Canes Venatici contains several galaxies like Messier 51, NGC4248, NGC 4242, NGC 4631, NGC4707.
Canis Major: It appears in southern hemisphere and has brightest star in the sky called as Sirius. Sirius is one of the closest stars in our universe that is close to earth Is the distance of 8.6 light years. It can be seen by naked eyes because it has a lot of bright stars in constellation compared to other star constellations. it resembles as a figure of dog. It has an area off 380 square degree. It has 7 more bright stars in addition to Sirius star.
Canis Minor: It is one of the tiniest constellations in northern celestial hemisphere. It has an area of 183 square degree and 2 bright stars in its constellation. It also has Nebula Abell 24. It has only 2 bright stars in its constellation.
Capricornus: Capricornus is one of the 12 signs of Zodiac constellations. it has an area of 414 square degree. It has 3 bright stars and of globular cluster messier 30. The brightest star Capricornia is a proximately 39 light years away from earth.
Carina: He’s one of the smallest constellations in the northern hemisphere. It has an area of 494 square degree And contain 9 bright star in its constellation. It also has deep Sky objects like NGC 2516 Which is an open cluster that cannot be seen by unaided eye.
Cassiopeia: Cassiopeia appears in the northern Sky. It hasn’t shaped like letter M. the middle star directly points to the polar star in the sky. It has 5 bright stars and an area of 598 square degrees. the brightest star in this constellation is Alpha centaury and the closest star to the sun.
Centaurus: The Centaurus is the brightest and the largest constellation in all constellations that appears in southern sky. It has largest constellation area of 1060 square degree. The two stars Alpha centuri and century are brightest star out of 12 brightest stars in its constellation. It also has one of the nearest Galaxy that is close to earth and has been actively revolving around. It has multitude of spiral galaxies, black holes, nebula in its region.
Cepheus: Cepheus Constellation appears in northern Sky. Constellations brightest star is Alpha Cephei. It has an area of 588 square degrees. It has seven bright star in its constellation. It also has deep Sky objects like NGC 188 and NGC 6946. NGC188 is a spiral cluster and NGC 6496 has 10 supernovae till date observed by astronomers.
Cetus: Cetus These are very long elongated constellation which has more than 14 bright stars. It also resembles as a snake. It has an area of 1231 square degrees. Messier 77 spiral Galaxy can be seen with the help of sophisticated telescope inside cetus constellation.
Chamaeleon: Chamaeleon constellation is very small constellation is northern Sky. It has an area of 132 squared degrees. It only has 3 bright star in its constellation.
Circinus: Circinus Is a very tiny constellation in southern Sky. It has an area of only 93 squared degrees with only 3 bright stars in its constellation. NGC 5283 please open cluster which is also called as Caldwell 88 is also present inside this constellation.
Columba: Columba Is a very tiny constellation wins northern hemisphere. Video it has an area of only 270 square degrees.
Coma Berenices: Coma Berenices Is a constellation in northern Sky on has an area of 386 square degrees. the famous M64 black eye Galaxy is present in coma berenices .
Corona Australis: Corona Australis Appears in southern celestial hemisphere. It only has an area of 128 squared degrees and 6 bright stars inside it.
Corona Borealis: It is a small constellation with period of 179 squared degrees. It appears on the northern celestial Hemisphere.
Corvus: Corvus is Small consolation with one 184 square degrees. NGC 4038 on NGC 4039 are present in Corvus constellation.
Crater: Crater is a constellation in southern hemisphere. It has an area of 280 square degrees. NGC 3983 Galaxy which is a satellite Galaxy of Milky Way is present inside this constellation.
Crux: constellation is primarily formed by four bright stars in the southern hemisphere. It is tiny star constellations with area of only 68 square degree. Coalsack nebula and IC2944 are part of deep sky objects in Crux constellation.
Cygnus: Cygnus appears on the northern sky in the line of milky way. It resembles the figure of bird. The brightest star in Cygnus constellation is Deneb, which is closest start to earth as per the magnitude of light. It has an area of 804 square degree with 9 bright stars. Due to its position right across milky way, we can see multitude of open clusters, nebulas and black holes in Cygnus constellation.
Delphinus: Delphinus appears in northern sky on the equatorial celestial. It has area of 189 square degree with 5 bright stars.
Dorado: Dorado is a constellation that appears in southern sky. It has an area of 179 square degree and various deep sky objects like galaxy NGC1566 and LEDA89996.
Draco: it is of the largest constellation in northern hemisphere. It resembles fiture of dragon and hence named afterword. It has massive area of 1083 square degree with 13 bright stars that highlights this constellation. Famous Cat’s eye nebula is present inside region of Draco galaxy but can been only seen by aided eyes.
Equuleus: it is a tiny constellation with an area of only 72 square degree. Till date galaxies NGC 7015, NGC 7040 and NGC 7046 are active in this constellation.
Eridanus: it is visible in southern hemisphere with large an area of 1138 square degree. It has 24 bright stars and out of them 32 probably planets with stars. Galaxies NGC 1232, NGC 1234, NGC 1292 and NGC 1300 are present inside this constellation.
Fornax: Fornax is appearing at northern hemisphere with an area of 398 square degree. Approximately there are 4 globular clusters visible in Fornax constellation.
Gemini: Gemini of the 12 Zodiac sign in our primary constellation. It appears as horizontally tilted U in left side. There two bright stars in this constellation that distinguish constellation from another constellation. M35, Medusa nebula and Eskimo nebula are distinct deep sky objects in this constellation. It has large area of 514 square degree.
Grus: it appears in southern sky with an area of 366 square degree. Sometimes it is also referred as flamingo constellation. There are multitude of double star in this constellation and they can be seen bu unaided eye. Spare-tyre nebula is one of the deep sky objects exists in Grus constellation.
Hercules: Hercules constellation appears alongside Draco, Ophiuchus and Bootes constellation. It is the biggest constellation with an area of 1255 square degree. Most of the bright stars are clearly visible with unaided eye. M13 and M92 galaxy clusters can be easily with naked eye within Hercules constellation.
Horologium: it appears in southern hemisphere with an are of 249 square degree. It resembles as titled right-angle figure in southern hemisphere.
Hydra: Hydra is largest constellation in all 88-star constellations with a super massive area of 1303 square degree. It resembles snake like long elongated figure due to alignment of its bright stars. The brightest star is Alphard with magnitude of 1.98. NGC 3923 and NGC 6535 appears inside Hydra constellation. It also has binary star epsilon hydrae.
Hydrus: Hydrus is a very tiny constellation with an area of 243 square degree. PGC 6240 galaxy is fainted deep sky objects that can be seen inside Hydrus region
Indus: it appears in the southern hemisphere. Constellation has an area of 294 square degree with 2 bright stars in its celestial region.
Lacerta: Lacerta is one of the latest identified constellations with an area of 201 square degree. NGC7243 is galaxy that can been seen with telescope appears in Lacerta constellation.
Leo: It is one of the 12 Zodiac sign and resembles a figure of lion. It has massive area of 947 square degree and has 5 messier objects like deep sky galaxies and nebula.
Leo Minor: it is a very tiny constellation that appears at northern hemisphere. It has area of 232 square degrees. It has 3 bright stars in its constellation out of which NGC 3021 spiral galaxy is more than 1 million lights years far away from earth.
Lepus: Lepus constellation can be seen at southern hemisphere. It has an area of 290 square degrees.
Libra: Libra is part of 12 zodiac constellations and astrology signs. It appears at the northern celestial hemisphere. Libra has one of the brightest open NGC5897. Libra constellation covers 538 square degrees of region in the northern sky.
Lupus: it appears over the southern sky. It is small constellation with area of 334 square degree. Nebula NGC5882 appears in the region of Lupus.
Lynx: Lynx constellation is visible in northern celestial hemisphere. It has an area of 545 square degree with 4 bright starts in its region.
Lyra: it appears over northern celestial hemisphere. Vega is brightest star in Lyra constellation. Vega is one. Vega is 2.7 timer larger than sun.
Mensa: Mensa constellation appears near the south pole of celestial hemisphere. It is a very tiny constellation with area of only 153 square degree.
Microscopium: it appears in southern celestial hemisphere. It has an area of only 210 square degree.
Monoceros: Monoceros is not enough bright and a appears on the celestial plane. It has area of 482 square degree. COROT-7b and COROT-7c are two possible exoplanets in this constellation. It has deep sky objects like M50 open cluster, Rosette Nebula and Christmas tree cluster.
Musca: it has area of 138 square degree and appear in the southern celestial hemisphere.
Norma: Norma appears at Southern Celestial Hemisphere. It has an area of 165 square degree, and it is a very faint constellation. However, it has lot of deep sky objects like open clusters but they don’t appear clear because Norma falls on the milky way.
Octans: Octans appears as a triable shape constellation. It has faint visibility and area of 291 square degree.
OPHIUCHUS: it is big constellation on the celestial equator. It has an area of 948 square degree and has brightest star named as Ophiuchi.
Orion: Orion appears on celestial equator. It has approximately 90+ planets and stars. Rigel and Betelgeuse are the brightest star in this constellation.
Pavo: Pavo constellation is visible in southern sky. It has area of 348 square degree containing 7 bright stars. Pavo includes deep sky objects like NGC 6572 which contains an estimated of 100k stars.
Pegasus: Pegasus is one of the largest constellations with area of 1121 square degree. It resembles to the picture of winged horse. It appears in northern celestial hemisphere. Pegasus constellation is famous for its position as lot of star, planets and star constellation can be identified without telescope.
Perseus: Perseus constellation appears in northern celestial hemisphere. It has area of 615 square degree. Algol, Alpha persei and Zeta persei are the brightest start in this constellation. It has deep sky objects like NGC 869 and NGC 884.
PHOENIX: it is very small constellation in the northern sky. It has an area of 469 square degree.
Pictor: Pictor constellation is visible in southern hemisphere. It has an area of 247 square degree. NGC 1705 is the brightest deep sky object in this constellation.
Pisces: Pisces is one of the 12 Zodiac signs in the star constellation. It represents the structure of two fish facing to each other’s head. It is a big constellation with area of 889 square degree.
Piscis Austrinus: it is constellation in southern celestial hemisphere. It is small constellation with area of 245 square degree.
Puppis: it is a medium size constellation with area of 673 square degree. It has three bright stars named as Naos, Tureis and Asmidiske. Since pupis falls on the milky way path, it has large number of open clusters like M46 and M47.
Pyxis: It is very small constellation in southern celestial hemisphere. It has an area of 221 sqaure degree and 3 bright stars.
Reticulum: it is also a small constellation in southern sky. It has an area of 114 square degree. Sagitta: Sagitta is the smallest constellation in the star constellations with area of 88 square degree.
Sagittarius: Sagittarius is one of the 12 zodiac signs, resembles a person pulling arrow with bow. It has deep sky objects like Messier 71.
Scorpius: Astronomy information sometimes referred as Scorpion is one of the 12 zodiac signs. It has an area of 497 square degree and hosts lot of deep sky objects like Messier 6, Messier 7, NGC 6231 , Messier 4 and Messier 80.
Sculptor: Sculptor is a small constellation with area of 475 square degree. It is barely visible with naked eye and requires sophisticated telescope to view complete star constellation.
Scutum: it is a small constellation with area of 109 square degree. Alpha Scuti is the brightest star in this constellation.
Serpens: Sperns constellation appears in the northern celestial hemisphere. It has an area of 637 square degree. It is home to deep sky object like Messier 5 which is one of the brightest cluster of galaxies.
Sextans: Sextans constellation lies on the equatorial plane and has an area of 314 square degree.
Taurus: Taurus is one of the 12 zodiac signs in star constellations. Lot of astronomer studying Pleiades and the Hyades star clusters as they are visible with naked eye and closest clusters to earth. It has an area of 797 square degree.
Telescopium: Telescopium is a small constellation with area of 252 square degree. It is home to galaxy cluster NGC6584.
Triangulum: Triangulum is a very small constellation with area of only 132 square degree. It lies in the northern celestial hemisphere.
TRIANGULUM AUSTRALE: it is very small constellation with southern celestial hemisphere. Astronomy information suggests that this constellation has an area of 110 square degree.
Tucana: Tucana lies within the southern hemisphere. It has an area of 295 square degree.
Ursa Major: Ursula Major resembles the figure of walking bear. With an area of 1280 square degree, Ursa major constellation stands one of the biggest and brightest star constellation in northern celestial hemisphere. It is home to deep sky objects M81, M82, M97, M102, NGC 2787, NGC 3097, NGC 3310, NGC 4013.
Ursa Minor: Ursa minor is a small constellation that lies in the northern hemisphere. It has an are of 256 square degree. NGC 6217 lays in this constellation.
Vela: Vela constellation appear in the southern sky as per astronomy information. It covers area of 500 square degree in the sky.
Virgo: Virgo is one of the 12 zodiac signs in the constellation and depicts the picture of a girl. constellation forms based on 9 bright stars. It covers massive area of 1294 square degree in the sky.
Volans: Volans constellation is visible in southern hemisphere with area of 141 square degree.
Vulpecula: Vulpecula appears in the northern sky and covers an area of 268 square degree. It is also home to Dumbbell nebula also referred to as M27.
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