Sunlight Destroys Coronavirus Quickly, Say US Scientists

It has long been known that ultraviolet light has a sterilizing effect, because the radiation damages the virus's genetic material and their ability to replicate.


Washington:

The new coronavirus is quickly destroyed by sunlight, according to new research announced by a senior US official on Thursday, though the study has not yet been made public and awaits external evaluation.

William Bryan, science and technology advisor to the Department of Homeland Security secretary, told reporters at the White House that government scientists had found ultraviolet rays had a potent impact on the pathogen, offering hope that its spread may ease over the summer.

"Our most striking observation to date is the powerful effect that solar light appears to have on killing the virus, both surfaces and in the air," he said.

"We've seen a similar effect with both temperature and humidity as well, where increasing the temperature and humidity or both is generally less favorable to the virus."

But the paper itself has not yet been released for review, making it difficult for independent experts to comment on how robust its methodology was.

It has long been known that ultraviolet light has a sterilizing effect, because the radiation damages the virus's genetic material and their ability to replicate.

A key question, however, will be what the intensity and wavelength of the UV light used in the experiment was and whether this accurately mimics natural light conditions in summer.

"It would be good to know how the test was done, and how the results were measured," Benjamin Neuman, chair of biological sciences at Texas A&M University-Texarkana, told AFP. 

"Not that it would be done badly, just that there are several different ways to count viruses, depending on what aspect you are interested in studying."

Virus inactivated 

Bryan shared a slide summarizing major findings of the experiment that was carried out at the National Biodefense Analysis and Countermeasures Center in Maryland.

It showed that the virus's half-life -- the time taken for it to reduce to half its amount -- was 18 hours when the temperature was 70 to 75 degrees Fahrenheit (21 to 24 degrees Celsius) with 20 percent humidity on a non-porous surface.

This includes things like door handles and stainless steel.

But the half-life dropped to six hours when humidity rose to 80 percent -- and to just two minutes when sunlight was added to the equation.

When the virus was aerosolized -- meaning suspended in the air -- the half-life was one hour when the temperature was 70 to 75 degrees with 20 percent humidity.

In the presence of sunlight, this dropped to just one and a half minutes.

Bryan concluded that summer-like conditions "will create an environment (where) transmission can be decreased."

He added, though, that reduced spread did not mean the pathogen would be eliminated entirely and social distancing guidelines cannot be fully lifted.

"It would be irresponsible for us to say that we feel that the summer is just going to totally kill the virus and then if it's a free-for-all and that people ignore those guides," he said.

Previous work has also agreed that the virus fares better in cold and dry weather than it does in hot and humid conditions, and the lower rate of spread in southern hemisphere countries where it is early fall and still warm bear this out.

Australia, for example, has had just under 7,000 confirmed cases and 77 deaths -- well below many northern hemisphere nations.

The reasons are thought to include that respiratory droplets remain airborne for longer in colder weather, and that viruses degrade more quickly on hotter surfaces, because a protective layer of fat that envelops them dries out faster.

US health authorities believe that even if COVID-19 cases slow over summer, the rate of infection is likely to increase again in fall and winter, in line with other seasonal viruses like the flu.

World

27,08,508Cases
17,79,729Active
7,37,994Recovered
1,90,785Deaths
Coronavirus has spread to 185 countries. The total confirmed cases worldwide are 27,08,508 and 1,90,785 have died; 17,79,729 are active cases and 7,37,994 have recovered as on April 24, 2020 at 8:40 am.

India

23,077 1684Cases
17,610 1156Active
4,749 491Recovered
718 37Deaths
In India, there are 23,077 confirmed cases including 718 deaths. The number of active cases is 17,610 and 4,749 have recovered as on April 24, 2020 at 8:00 am.

State & District Details

State Cases Active Recovered Deaths
DistrictCases
Mumbai3029
Pune660
Thane465
Nashik96
Nagpur76
Mumbai Sub Ur67
Yavatmal32
Aurangabad30
Sangli27
Ahmednagar27
Sholapur21
Buldhana21
Palaghar17
Akola17
Raigad17
Satara14
Kolhapur8
Latur8
Ratnagiri7
Amravati6
Jalgaon3
Osmanabad3
Sindhudurg (kudal)2
Chandrapur2
Dhule2
Beed1
Washim1
Parbhani1
Jalna1
Nandurbar1
Gondia1
Hingoli1
Details Awaited*1766

6430 778

5307 713

840 51

283 14

DistrictCases
Ahmedabad1298
Surat338
Vadodara188
Rajkot40
Bhavnagar32
Anand28
Bharuch23
Gandhi Nagar17
Patan15
Narmada12
Panchmahal11
Banaskantha10
Arvalli8
Chhota Udepur7
Kutch6
Mehsana6
Botad5
Porbandar3
Mahisagar3
Kheda3
Gir Somnath3
Dahod3
Sabarkantha2
Valsad2
Morbi1
Jamnagar1
Tapi1
Details Awaited*558

2624 217

2254 129

258 79

112 9

DistrictCases
Tj From Quaritine1080
Others Non Tracable213
Central Delhi184
South East130
West Delhi122
South Delhi70
North Delhi60
Shahadara48
South West Delhi42
East Delhi38
New Delhi37
North West Delhi32
North East Delhi25
Details Awaited*295

2376 128

1518 42

808 84

50 2

DistrictCases
Jaipur537
Jodhpur228
Bharatpur102
Kota99
Tonk95
Banswara60
Iran Evacuees60
Nagaur58
Jhunjhunu37
Bikaner35
Jaisalmer32
Bhilwara28
Ajmer23
Jhalawar20
Churu14
Dausa13
Alwar7
Dungarpur5
Sawai Madhopur5
Udaipur4
Hanumangarh3
Karauli3
Pali2
Pratapgarh2
Sikar2
Dholpur1
Barmer1
Details Awaited*488

1964 74

1707 74

230

27

DistrictCases
Indore915
Bhopal277
Khargon41
Dhaar41
Khandwa (east Nimar)32
Ujjain29
Raisen29
Hoshangabad25
Jabalpur25
Barwani24
Dewas18
Vidisha13
Ratlam13
Morena13
Mandsaur9
Agar8
Shajapur6
Sheopur-kalan4
Alirajpur3
Gwalior3
Sagar2
Shivpuri2
Chindwara2
Betul2
Rajgarh1
Dindori1
Tikamgarh1
Details Awaited*160

1699 107

1413 49

203 55

83 3

DistrictCases
Chennai303
Coimbatore133
Tiruppur109
Dindigul76
Erode70
Tirunelveli62
Chengalpattu53
Tiruchirapalli50
Namakkal50
Thiruvallur48
Thanjavur46
Madurai46
Nagapattinam44
Theni43
Karur42
Ranipet39
Villupuram36
Thoothukudi27
Thiruvarur27
Cuddalore26
Tenkasi26
Salem24
Vellore22
Virudhunagar19
Tirupattur17
Nagerkoil (kanyakumari)16
Sivagangai12
Tiruvannamalai12
Ramanathapuram11
Udagamandalam9
Kancheepuram9
Perambalur5
Ariyalur4
Kalllakurichi3
Pudukottai1
Details Awaited*163

1683 54

911

752 90

20 2

DistrictCases
Agra241
Lucknow167
Gautam Budha Nagar98
Meerut75
Saharanpur72
Kanpur59
Firozabad58
Moradabad58
Ghaziabad41
Shamli26
Bijnor26
Basti19
Bulandshahar18
Sitapur17
Hapur17
Amroha17
Baghpat15
Rampur15
Varanasi14
Budaun13
Azamgarh7
Auraiya7
Sambhal7
Mathura6
Maharajganj6
Ghazipur6
Kannauj6
Pratapgarh6
Bareilly6
Muzaffar Nagar5
Jaunpur5
Lakhimpur Kheri4
Mainpuri4
Hathras4
Kanshi Ram Nagar (kasganj)3
Mirzapur3
Etah3
Etawah3
Kaushambi2
Banda2
Pilibhit2
Hardoi2
Rae-bareilly2
Unnao1
Sultanpur1
Bara-banki1
Sant Kabir Nagar1
Shahjahanpur1
Sant Ravi Das Nagar (bhadoi)1
Mau1
Gonda1
Allahabad1
Details Awaited*334

1510 61

1280 25

206 33

24 3

DistrictCases
Hyderabad472
Suryapet75
Nizamabad56
Vikarabad36
Hyderabad Rural (ranga Reddy)35
Gadwal (jogulamba)32
Medchal30
Warangal25
Adilabad19
Karimnagar19
Nirmal18
Yadadri15
Nalgonda15
Mahaboobnagar12
Kamareddy11
Sangareddy8
Khammam7
Medak6
Asifabad (komarambhim)5
Kothagudem (badadri)4
Jagityal3
Siricilla (rajanna)3
Bhupalpally (jayashanker)3
Nagarkurnool2
Peddapally2
Mulugu2
Janagoan2
Siddipet1
Mahabubabad1
Details Awaited*41

960 15

739 11

197 3

24 1

DistrictCases
Kurnool158
Guntur128
Krishna76
Nellore67
Prakasam44
Kadapa37
West Godavari35
Anantapur29
Chittoor28
East Godavari24
Visakhapatnam20
Details Awaited*249

895 82

727 58

141 21

27 3

DistrictCases
Kolkata184
Howrah79
North 24 Parganas46
Purba Mednipur21
Hooghly12
South 24 Parganas9
Kalimpomg7
Paschim Burdwan7
Nadia6
Jalpaiguri5
Darjeeling4
Paschim Mednipur4
Diamond Harbour-hd3
Murshidabad2
Basirhat-hd1
Purba Burdwan1
Nandigram-hd1
Details Awaited*122

514 58

396 34

103 24

15

DistrictCases
Kasaragode170
Cannanore(kannur)92
Ernakulam24
Kozhicode (calicut)20
Malappuram20
Pathanamthitta17
Thiruvananthapuram14
Thrissur13
Idukki10
Kollam9
Palakkad8
Alappuzha5
Kottayam3
Wyanad3
Details Awaited*39

447 9

120 8

324 1

3

DistrictCases
Mysuru84
Bbmp66
Belagavi42
Vijayapura32
Kalburgi27
Bengaluru (u)23
Bagalkote21
Chikkaballapur16
Bidar15
Dakshin Kannada14
Ballari13
Mandya12
Bengaluru (r)12
Uttara Kannada11
Dharwad7
Gadag4
Udupi3
Tumakuru2
Davanagere2
Kodagu1
Chitradurga1
Details Awaited*37

445 18

283 4

145 14

17

DistrictCases
Bandipora81
Srinagar79
Baramulla43
Kupwara31
Jammu27
Shopian22
Udhampur20
Ganderbal14
Badgam13
Kulgam6
Rajouri4
Samba4
Anantnag3
Pulwama3
Details Awaited*77

427 20

330 20

92

5

DistrictCases
Sasnagar61
Jalandhar48
Patiala26
Pathankot24
Nawanshahr (sbs Nagar)19
Ludhiana16
Amritsar11
Mansa11
Hoshiarpur7
Moga4
Rupnagar3
Sangrur3
Faridkot3
Kapurthala2
Barnala2
Fatehgarh Sahib (sarhind)2
Muktsar1
Gurdaspur1
Firozepur1
Details Awaited*32

277 26

196 10

65 16

16

DistrictCases
Nuh57
Faridabad42
Gurgaon38
Palwal34
Panchkula18
Ambala12
Sonepat7
Karnal6
Panipat5
Sirsa4
Yamunanagar3
Bhiwani3
Kurukshetra2
Kaithal2
Jind2
Hissar2
Rohtak1
Fatehabad1
Charkhi Dadri1
Details Awaited*32

272 10

113

156 16

3

DistrictCases
Siwan29
Nalanda28
Munger20
Begusarai9
Patna7
Gaya5
Buxar4
Gopalganj3
Nawada3
Bhagalpur1
Bhojpur1
Lakhisarai1
Saran1
Vaishali1
Details Awaited*40

153 10

105 10

46

2

DistrictCases
Khurda (bhuvaneshwar)46
Bhadrak8
Balasore3
Jajpur2
Kalahandi2
Kendrapara2
Sundargarh2
Cuttack1
Dhenkanal1
Puri1
Details Awaited*22

90 7

56 6

33 1

1

DistrictCases
Ranchi25
Bokaro10
Hazaribagh3
Dhanbad2
Simdega2
Deoghar1
Giridh1
Koderma1
Details Awaited*8

53 4

42 4

8

3

DistrictCases
Dehradun24
Nainital9
Haridwar7
Udhamsingh Nagar4
Almora1
Pauri Garhwal1
Details Awaited*1

47 1

23

24 1

0

DistrictCases
Una16
Solan9
Chamba6
Kangra5
Hamirpur2
Sirmaur1
Details Awaited*1

40

21

18

1

DistrictCases
Korba28
Raipur5
Bilaspur1
Durg1
Rajnandgaon1

36

8

28 2

0

DistrictCases
Golaghat9
Marigaon6
Dhubri4
Goalpara4
Nalbari4
Kamrup Metro2
Cachar1
Hailakandi1
Kamrup1
Karimganj1
Lakhimpur1
S Mancachar1
Details Awaited*1

36 1

16 1

19

1

DistrictCases
Chandigarh26
Details Awaited*1

27

13

14

0

DistrictCases
South Andaman16
Details Awaited*6

22 4

11 4

11

0

DistrictCases
Leh (ladakh)14
Details Awaited*4

18

4

14

0

DistrictCases
East Khasi Hills11
Details Awaited*1

12

11

0

1

DistrictCases
Puducherry6
Details Awaited*1

7

4

3

0

DistrictCases
North Goa6
South Goa1

7

0

7

0

DistrictCases
Imphal West1
Thoubal1

2

0

2

0

DistrictCases
Gomati1
North Tripura1

2

1

1

0

DistrictCases
Aizwal West1

1

1

0

0

DistrictCases
Lohit1

1

0

1

0

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