Author: Abhishek Kumar, Chief Editor , Biotechticle Research Group(BTRG)

Severe acute respiratory syndrome coronavirus infection or coronavirus diseases 2019 (COVID-19), has caused an unprecedented loss of lives and livelihood all over the world. By 16th May, 2020 approximately 4.6 million people have tested positive for COVID-19 and 310,000 people have died due to the disease. Recently biotechticle published an article explaining the reasons of the spread and impact of the disease.

COVID-19 is a respiratory infection. SARS-CoV-2 is the virus that causes coronavirus disease. It can be transmitted by respiratory droplets of size between 5-10 micrometers. Droplet transmission occurs when people are in close contact within 1m with an infected person. Hence, people are advised to prevent exposure of the mouth, nose, or eye with the contagious droplets [1].

Unfortunately, recent reports suggest that the virus can also spread through airborne transmission, faecal-oral transmission and sexual transmission.

Airborne transmission: Virologist Ke Lan at Wuhan University has submitted an article for publication [2] which claims that their team was able to find viral RNA from SARS-CoV-2 in the aerosols collected from numerous public places like department stores. However, the study is yet to ascertain whether these RNA samples can cause infections. It is difficult to determine the viral load (Amount of virus that gives a certain chance of infection) for a severe disease like COVID-19 [3]. Since it would be unethical to deliberately expose people and measure the rate of infection for various doses. Additionally, the length of exposure to the virus might be important too. Hence, public health officials across the world are advising to wear masks and prevent crowds.

Faecal-oral transmission: In this type of transmission pathogens in faecal particles of an individual can be transmitted to another. Main causes of this transmission is poor hygiene and absence of adequate sanitation. It is a very common mode of disease transmission in a relatively poor country like India, where a huge number of people still do not have proper sanitation facilities. Diseases like typhoid, diarrhoea, cholera and hepatitis are caused by faecal-oral transmission. Moreover, the virus viability of these diseases is very high. Recently, a research study at Guangzhou Medical University, found that eight children tested positive on rectal swabs even after nasopharyngeal testing was negative [4]. This has caused a possibility of faecal-oral transmission of COVID-19 disease.

Sexual transmission: In another study published in JAMA Network Open and conducted in Shangqui, China, 6 patients out of 38 COVID-19 positive males had the virus in the semen. Out of the 38, four males were in an acute stage whereas two had already recovered [5]. However, in another study, no coronavirus was detected in 34 males recovering from COVID-19 [6]. The difference of the results could be attributed to the seriousness of the diseases. Additionally, the sample size (number of patients considered in the study) was low for statistically significant results. Both did not follow the patients to determine whether the men had spread the virus to their partners. Dr. Anne Rimoin, professor of epidemiology, UCLA during an interview with CNN advised people to practice abstinence or safe sex after being sick since we are still learning about the virus [7].

Any viral infection replicates, circulates, and goes into most of the tissues. It is not surprising that coronavirus is present in different body fluids. However, sometimes the viral load of in the fluids might be very low. The disease has spread throughout the world and every day thousands of people are getting infected. So, it becomes essential to study and understand the virus to better protect individuals. The assumption should be that these modes of transmission are possible unless experimental evidence rules them out. Better be safe than sorry.

References: 

1.https://www.who.int/csr/don/12-january-2020-novel-coronavirus-china/en/
2.Liu, Y. et al. Preprint at bioRxiv http://doi.org/dqts (2020).
3.Yan, J. et al. Proc. Natl Acad. Sci. USA 115, 1081–1086 (2018).
4.Xu, Y. et al. Characteristics of pediatric SARS-CoV-2 infection and potential evidence for persistent faecal viral shedding. Nat. Med. https://doi.org/10.1038/s41591-020-0817-4 (2020)
5.Li D, Jin M, Bao P, Zhao W, Zhang S. Clinical Characteristics and Results of Semen Tests Among Men With Coronavirus Disease 2019. JAMA Netw Open. 2020;3(5):e208292. doi:10.1001/jamanetworkopen.2020.8292
6.Pan F, Xiao X, Guo J, Song Y, Li H, Patel DP, Spivak AM, Alukal J,P, Zhang X, Xiong C, Li PS, Hotaling JM, No evidence of SARS-CoV-2 in semen of males recovering from COVID-19, Fertility and Sterility (2020), doi: https://doi.org/10.1016/j.fertnstert.2020.04.024.
7.https://edition.cnn.com/videos/health/2020/05/08/coronavirus-mens-semen-baldwin-intv-nr-vpx.cnn/video/playlists/coronavirus/