The Effect of Temperature Upon Transmission Of COVID-19 : Australia And Egypt Case Study

Background: Several previous studies have recognized the effect of air temperature on the survival and transmission of viruses and germs. The current study investigated the effect of air temperature on the transmission of coronavirus covid-19 by monthly temperature averages maps analyzing. Methods: The study demonstrated the relationship between temperature and transmission speed of Covid-19 virus, It conrmed that the most appropriate average temperature for virus activity and transmission ranges between 13-24 ° C, by analyzing the maps of monthly temperature averages in Egypt and Australia. Results: The study reached, through cartographic analysis, to conrm the relationship between temperature and increase in the number of conrmed cases of covid-19, This study conrmed that the most appropriate average temperature for virus activity and transmission ranges between 13-24 ° C, by analyzing the maps of monthly temperature averages in Egypt and Australia. Conclusions: Results support that the most appropriate average temperature for the survival transmission of COVID-19 ranges between 13-24 ° C. Australia and Egypt are models to conrm the relationship between temperature and COVID-19 activity and spread.

There is a relationship between air humidity and the life of bacteria and viruses. The in uenza virus dies more quickly in conditions of high humidity accompanied by fast moving air, so the winter months in which humidity decreases and the speed of air movement decreases are more appropriate for the spread of respiratory infections(). It was also found that the TB germ, if exposed to sunlight, stops its activity within one hour. Whereas in the normal light, it remains active between 6-24 hours, and in the dark, it lives in a state of activity between two and eighteen months, so chest diseases hospitals must be established in sunny areas. ( Multiple countries have con rmed travel-associated cases, including Australia, Cambodia, Canada, France, Germany, Japan, Nepal, Singapore, South Korea, Taiwan, Thailand, United Arab Emirates, United States, and Vietnam. Vietnam identi ed the rst human-to-human transmission outside China()..As of 30 Mars 2020 The highest cases were recorded in United States of America, Italy, and china.
(Jin Bu et al) nd that the suitable temperature range for 2019-nCoV survival is (13-24 °C), among which 19 °C lasting about 60 days is conducive to the spread between the vector and humans; the humidity range is 50%-80%, of which about 75% humidity is conducive to the survival of the coronavirus; the suitable precipitation range is below 30 mm/ month. The prediction results show that with the approach of spring, the temperature in north China gradually rises, and the coronavirus spreads to middle and high latitudes along the temperature line of 13-19 °C (). "Jingyuan Wang et al" nd that after estimating the serial interval of COVID-19 from 105 pairs of the virus carrier and the infected, they calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of non-intervened transmission intensity, they nd, under a linear regression framework for 100 Chinese cities, high temperature and high relative humidity signi cantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities. One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively(7).
Comparison of meteorological conditions of the onset of 2019-nCoV pneumonia in 2019 and SARS pneumonia in 2003, from October to November 2019 in Wuhan, the mean temperature in Wuhan dropped from 18.28 °C to 13.43 °C. Humidity remained between 73.12% and 77.58%, and the rst few cases of the 2019-nCoV pneumonia occurred in early December. The meteorological conditions signi cantly overlapped with those of SARS onset in Guangzhou. In the winter of 2002, the temperature was between 13.85 °C to 15.85 °C, and humidity kept between 69.05% and 78.91% in Guangzhou. Considering the data above including 2019-nCoV in Wuhan, SARS coronavirus in Guangzhou and Beijing, we speculate that a meteorological condition with temperature between 13-19 °C and humidity between 50% and 80% is suitable for the survival and transmission of the coronavirus. (Jin Bu, et al, 2020) Lower rainfall and therefore reduced relative humidity provide a good opportunity for the transmission of respiratory pathogen infections, including coronavirus. ()

Methods:
The paper attempted to test that the most appropriate average temperature for virus activity and transmission ranges between 13-24 ° C in reality through maps of the monthly temperature averages during the period from March to November 2020, through study of the case of Australia and Egypt. The study tried to predict the future of the virus spread during the upcoming seasons through cartographic methods, Climate maps were obtained from Australia's national weather, climate and water agency, The Bureau of Meteorology, USGS: Early Warning and Environmental Monitoring Program, and ACC weather. Con rmed cases numbers were gathered from Australian Government Health Department, and WHO. The case studies of Egypt and Australia were chosen as two models for different climates, and for comparison between two countries, one of which is in the northern hemisphere (Egypt), and the other is located in the southern hemisphere (Australia).

Results:
The study reached, through cartographic analysis, to con rm the relationship between temperature and increase in the number of con rmed cases in Australia during the month of March, and also the decrease in the number of cases in Egypt in the same month, The number of con rmed cases was 710 in Egypt vs 4560 in Australia. Excluding the impact of other factors, The study expects that the countries of the northern hemisphere will turn to more hot seasons, which means low virus activity and weak transmission. On the contrary, the countries of the southern hemisphere are heading towards less hot seasons and thus the possibility of more activity of the virus and a greater possibility of transmission than the northern hemisphere. In both cases, people must adhere to health and social instructions to prevent the virus transmission from one person to another. Conclusions most appropriate average temperature for the survival transmission of COVID-19 ranges between 13-24 °C . Australia and Egypt are models to con rm the relationship between temperature and COVID-19 activity and spread. Globally, cities with a mean temperature below 24 °C are all high-risk cities for 2019-nCoV transmission. Especially in the northern spring, and southern autumn and winter. Therefore, countries should take the necessary precautions to prevent the spread of the epidemic.
The case study of Australia: The validity of these results has also been demonstrated through the case study of Australia. In Australia, the rst case appeared in Melbourne on January 19 for a Chinese person coming from Guangzhou, and the numbers during January and February were very few (the southern summer months) with 9 cases recorded in January, and only 12 cases in February, Applying to Australia, we nd that through Figure ( The Situation During the Summer: Looking at Figure (1), it is noted that the area which covered by average temperatures 12: 24 ° C in January (the middle month in the southern summer that runs from December to February) was a small strip in southern Australia, In this region the city of Melbourne is located, which is the city that had the rst cases of infection in Australia ,and which located in the temperature range 18:21 ° C.
In February (Fig. 1) the conditions remained the same with a small increase in the area of this southern strip of the country, which is located in a temperature range less than 24 ° C, but with a noticeable increase in the area of land which is located in the temperature ranges from 24-27 and from 27-30 ° C.
This was likely to have played a role in slowing the natural spread of the virus.
The situation during the fall: However, the matter differed a lot in March (Beginning of the southern fall, which extends from the beginning of March to the end of May), as it is observed from Figures (2) and (3) All the lands of the state of Victoria, which came second in terms of the number of con rmed cases (917 cases).
Southeast Queensland, which ranked third (743 cases), and wherever Brisbane is located where a large number of cases are recorded.
About a third of the area of Western Australia, in which the city of Perth is located in the southwest of the state, located at the temperature line 21 °C. It came in fourth place (364 cases) Half of the area of the state of south Australia, which came in fth place (337 cases) Note that the northern province, which located completely in a temperature range greater than 24 °C has recorded the lowest number of con rmed cases (only 16 cases), also we nd that the state of Tasmania, the island state, most of its lands located in a temperature zone less than 12 °C, has registered 68 cases.
Accordingly, if we exclude the effect of other factors, Australia is a model to con rm the relationship between temperature and coronavirus activity and spread, In March, it became clear that the areas most affected and spread by the virus are the regions with an average temperature of 12-24 °C. And the northern province with the average temperature above 24 °C (in the far north) and the state of Tasmania, in which the average temperature located below 12 °C in the far south, Both of them scored very few cases.
Perhaps a simple presentation of the numbers of infections during March may explain the effect of lower temperatures during this month on the speed of transmission of the virus, in March there were large consecutive numbers, as shown in Figure (4-A). The numbers recorded during this month reached to 4087 cases until 3/28/2020 . The new cases remained less than 25 cases per day from 1-15 March, then  became within 50 cases per day from 12 to 15 March, from 80 to 150 cases per day from 16 to 19 March,  from 150 to 300 cases in the period 20-22 March, from 300 to 400 cases daily during the period from March 23-27, then the number jumped to 459 cases on March 28. Figures (4-B) shows that the rate of multiplication of numbers was almost every 3 days during March.
Australia may face a major crisis during the rest of the autumn months (April and May). As can be seen from Fig. 5,In April about 75% of Australia's land will located between 12-24 °C heat lines. While in May most of Australia's lands will become between 12-24 °C heat lines, with the exception of its northern fringes, where the average temperature rises above 24 °C, and its southeastern side, where the temperature will drop below 12 °C, which also means that Coronavirus activity can be disabled in these areas.
The situation during the winter: The risk is expected to increase in the southern winter months (June -July -August) in the central and northern regions, where the average daily temperature ranges between 12-24 ° C, While the temperature of the south will be less than 12 degrees Celsius, that is, the risk will be relatively less for these areas.
During the months of June and July (Fig. 6), the southern half of Australia cools below 12 °C, while it ranges from 13-24 in the northern half, whereby it increases the activity of the Coronavirus, In August, the 12 °C heat line shifts southward, reducing the area of land where the risk of spreading the virus decreases, And the area of the thermal zone extends from 12 to 21 °C to include all the central and northern lands, where there is a risk of virus spreading.
Egypt case study: By comparison between Australia, as a country in the Southern Hemisphere, and Egypt, as a country in the Northern Hemisphere, there are signi cant climatic differences, as the month of April is the heart of autumn in Australia while it is the Heart of Spring in Egypt, and the severity of the impact of temperature on the transmission and activity of Coronavirus is increasing in Australia than in Egypt, where Australia is heading towards winter and lower temperatures, while Egypt is heading to the transition towards the summer, which has high rates of heat, and thus the activity and transmission of the virus are expected to decrease.
The situation in the spring: From Figure No. (7-A), which shows the mean daily temperature average in Egypt in the spring, it is clear that: In March, the southern half of Egypt is located in a heat range from 25 to 32 °C, and all of the governorates of the Delta, Matrouh, the Sinai Peninsula, the northern Red Sea governorate, and the north of the New Valley Governorate are in a temperature range of 16 to 24 °C. The number of con rmed cases was 710 vs 4560 in Australia.
In April, most of the Egyptian lands are located in a temperature average of more than 24 °C, except for most of the Sinai Peninsula and the northern coast of Egypt from Rafah to Salloum. Its temperature ranges between 20-24 degrees Celsius.
In May, temperatures rise above 26 degrees Celsius in all Egyptian lands, ranging between 26 degrees on the northern coasts, the Red Sea coasts and most of the Sinai lands, but in southern Egypt the temperature reaches 42 degrees.
From the above, it is clear that the effect of temperature on transmission and activity of COVID-19 in Egypt was higher in March than April, while the activity and transmission of the virus will be completely weakened in May, Excluding the impact of other factors. It remains the role of citizens in adhering to health rules, social separation and sanitary isolation, in order to prevent transmission of the virus from one person to another.
The situation in the Summer: From Figure (7-B), which shows the mean daily temperature average in Egypt in the summer, it is clear that temperatures will be between 28-40 degrees in June and between 30-40 in July and August all over Egypt.
The situation in the Autumn: From Figure (7-C), which shows the mean daily temperature average in Egypt in the autumn it is clear that In September, most of the Egyptian lands will be in a temperature range higher than 28 degrees. In October, the rate will be between 26 degrees in the far north and 38 degrees in the far south. In November, the line between Assiut and Hurghada divides Egypt into almost two halves, the northern half will have a mean temperature of less than 24 degrees, and the northern half will have a temperature above 24 degrees.

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