Journal of Life Science and Biomedicine  
J Life Sci Biomed, 10 (3): 21-28, 2020  
ISSN 2251-9939  
COVID-19 and avian corona viruses: epidemiological  
comparison and genetic approach  
Laboratory of Science and Technique of the Living, University of Mohamed Cherif Messaâdia, Souk Ahras, Algeria  
Original Article  
Aim. This study aimed to collect and analyse available information on COVID-19 and avian  
corona viruses in order to conduct a systematic review of the genetic data concerning them.  
PII: S225199392000004-10  
Methods. All available research was done according to the strictest data selection criteria,  
and the databases like NCBI genebank were quantitatively searched in the currently  
Rec. 18 April 2020  
Rev. 07 May 2020  
Pub. 25 May 2020  
available scientific literature using keywords, analytical statistic and genomic software. All  
studies on the coronavirus family were dedicated to provide an overview towards an  
advanced statistical analysis of the collected data. The first step was a descriptive study of  
COVID-19 and avian corona viruses by an epidemiological comparison between the two  
cases. Results. All corona viruses usually tend to have relatively A-T rich DNAs which is  
linked to their highly A-T rich codon biases. The results indicate genetic differences  
between the two viruses, but the results of a percentage analysis showed that the  
nucleotides A+T are both more abundant and energetically cheaper than nucleotides G+C,  
this gives viruses a selection advantage. Conclusion. These results give us a future positive  
view of this type of virus with AT-rich genomes which is selectively promoted at the host  
level. Recommendation. A recommendation by our study reveals that thought about the  
vaccine is very early but prevention has proven to be effective for this virus in chickens.  
Avian corona virus,  
Genomic analysis  
Coronaviruses (so called because they present a crown or corona shape) infect birds and many mammals,  
including humans [1] (Figure 1). The respiratory tract, gastrointestinal organs, and neurological tissues are the  
most common targets of coronaviruses, but other organs including the liver, heart, kidneys, and eyes may also  
be affected [2-4]. Epithelial cells are the primary targets  
of coronaviruses [5]. Widely distributed cells such as  
macrophages are also often infected by coronaviruses;  
mutation by definition late phase of the cycle during  
which changes in the structure of the viral particle are  
observed linked to the proteolysis of certain capsid  
proteins by a viral protease, maturation is essential for  
the viral particle to be infectious, coronaviruses are  
relatively restricted in their host spectrum, infecting  
only their natural host, and relatively close animal  
species [6, 7].  
Figure 1. The Typical structure of coronavirus [16-18]  
Figure 2 shows that coronavirus infection crosses the species barrier occasionally, as in the case of turkey  
infection with bovine coronavirus (BCoV), or experimental infection of dogs with TGEV; this may have  
happened with SARS (Severe Acute Respiratory Syndrome) in 2001, MERS (Middle East respiratory syndrome  
coronavirus) in 2012 and currently COVID-19 [8-12]. The biological vectors of the virus are poorly known and its  
transmission by respiratory, faecal and oral routes are common [13]. The coronavirus genome encodes a spike  
protein (S), an envelope protein, a membrane protein, and a nucleoprotein in this order. Among them, spike  
protein is the most important surface membrane protein of coronavirus [14, 15].  
This study aimed to conduct a systematic review of the genetic data on COVID-19 and avian corona  
viruses by analyzing available information.  
Citation: Berghiche A. COVID-19 and avian corona viruses: epidemiological comparison and genetic approach. J Life Sci Biomed, 2020; 10(3): 21-28; DOI:  
Figure 2. Phylogenetic tree analysis of the nucleocapsid genes from different coronaviruses. The alignments  
were performed using Clustal W, and the tree was created using a Neighbor Joining method with no outgroup  
(Past 2.17c).  
The Coronaviridae belong to the order Nirovirales which includes two other viral families, the Arteriviridae  
and the Ronoviridae; the Coronaviridae include the genera Coronaviridae and Toroviridae [19], with the following  
characteristics (Table 1). Infections of humans and animals with coronaviruses appear to be ubiquitous, as  
evidence of infection has been obtained in all countries where serological and virological studies have been  
carried out [20, 21]. According to the Baltimore classification [22, 23], coronaviruses are single-stranded viruses  
(unsegmented RNA+) of the 4th multiplication class (Figure 3).  
Table 1. Characteristics of Coronaviridae [24-27].  
Positive single-stranded RNA with polyA tail  
5'Polymerase gene - 3' structural protein genes  
The incipient 3'co-terminal carries at least 4 subgenomic mRNAs.  
Only the 5' region of the mRNA is translationally active.  
Ribosomal reading frame shift in the polymerase gene  
An M protein with at least 3 membrane-crossing sequences  
Intracellular sprouting  
Genome size in kB  
Sequence 5' Leader  
Prominent spicules (spike)  
Spicules helix/propeller structure  
Citation: Berghiche A. COVID-19 and avian corona viruses: epidemiological comparison and genetic approach. J Life Sci Biomed, 2020; 10(3): 21-28; DOI:  
Figure 3. Multiplication of Coronavirus [28].  
Epidemiological comparison  
In table 2, we have summarized the difference between COVID-19 and avian corona viruses through the  
different epidemiological points.  
Table 2. Epidemiological comparison between human and avian coronaviruses  
Comparative aspects  
Avian corona virus  
Epidemic [29]  
Pandemic [30]  
The respiratory tract, through aerosols  
and faeces [31]  
Transmission Routes  
The respiratory tract [30]  
Horizontal Direct and indirect; Vertical  
Mode of Transmission  
Horizontal Direct [33]  
2 day to 14 day  
5.2 days (95% confidence interval [CI], 4.1 to  
7.0), with the 95th percentile of the  
distribution at 12.5 days. [34, 35]  
18-36 hours [32]  
100 % [31]  
WHO's estimated (on Jan. 23, 2020) Ro1 to be  
between 1.4 and 2.5.  
Other studies have estimated a Ro between  
3.6 and 4.0, and between 2.24 to 3.58. [36]  
20% to 30% (except for the renal tropism  
strain) [31]  
2% (the elderly, Chronic diseases and  
immunodeficiency) [36]  
Signes respiratoires  
Signes reproducteurs  
Signes rénaux [37]  
Shortness of breath [38]  
Indirect ELISA (easy to use, but expensive),  
Hemagglutination inhibition (applicable  
and less expensive) and Viral neutralization  
RT-PCR [39]  
1 Transmissibility or the attack rate of virus is indicated by its reproductive number (Ro, pronounced R-nought or r-zero), which represents  
the average number of people to which a single infected person will transmit the virus.  
Citation: Berghiche A. COVID-19 and avian corona viruses: epidemiological comparison and genetic approach. J Life Sci Biomed, 2020; 10(3): 21-28; DOI:  
Genetic approach; descriptive data  
The genome analysis of the complete avian infectious bronchitis virus and SARS-CoV-2 virus shows a  
length of 27608 and 29903 amino acids respectively. Genomic composition analysis of the two viruses show the  
results summarized in Table 3. The comparison of the composition of the two viruses shows that there is a  
remarkable difference in the numbers of adenine for the avian virus (Figure 4).  
Table 3. Genomic composition of avian infectious bronchitis virus and SARS-CoV-2  
Genomic composition  
SARS Cov-2  
Avian Cov  
Total count  
Genetic sequences are collected from the NCBI GenBank and the analysis is performed using the bio edit software [40].  
Sars Cov 2  
Avian Cov  
Figure 4. Comparison between the amino acid composition of Avian Infectious Bronchitis Virus and SARS-CoV-2  
Genetic approach: Statistical analysis  
On the basis of the results using the software Past, of the composition of the two viruses, the F and t test  
(non-parametric test) was carried out, in order to estimate the existence of a significant difference between the  
different components of the same virus family, and whether the amino acid level shows a variety of  
pathogenesis of the virus species [41]. The analysis show a signification with F test which means that little  
difference in virus composition don’t change the pathogenicity characters according to [42].  
Table 4. F and t test Statistical table of composition  
SARS CoV-2  
Avian Cov  
4137.7 10814  
3593.3 10211  
95% Confidence for difference between means  
F: 1.018  
t: 0.38865  
p: 0.98863**  
p: 0.71095  
p: 0.71095  
p: 0.6524  
Welch test: unequal variance t=0.38865  
Permutation t test (N=9999):  
Citation: Berghiche A. COVID-19 and avian corona viruses: epidemiological comparison and genetic approach. J Life Sci Biomed, 2020; 10(3): 21-28; DOI:  
Figure 5. Box plot of Avian Infectious Bronchitis Virus and SARS-CoV-2 composition  
Genetic approach: Genomic data analysis  
The contents show that both viruses have a low level of G+C with 37.93 and 37.97 and high level of A+T with  
62.068 and 62.02 respectively. Meaningfully, intracellular genetic elements that persistently or temporarily  
exist outside the host chromosome [43, 44], such as viruses, are also generally characterized by a higher AT  
content than their host genome [45]. The coronavirus genome is filled with A and T [46]. Since nucleotides A + T  
/ U are both more abundant and less energetically expensive than nucleotides G + C, this gives viruses a  
selection advantage [47, 48]. Intracellular elements, whose genome is richer in A than the host genome, are  
selectively favoured at the host level [49].  
Figure 6. The Guanine+Cytosine and Adenine+Thymine contents of Avian Infectious Bronchitis Virus and SARS-  
This study gave a complete comparison of the two viruses in an epidemiological context and the exhaustive  
results of genomic composition contributed strongly to determine the difference between the two viruses and  
show their selectivity characteristics.  
Based on the experience with this virus in poultry, thinking about the vaccine is a bit early because the  
presence of several serotypes of the virus requires the use of several valences in the same vaccine, but the  
prediction of the A+T level can help in the preparation of possible vaccine ranges as in the case of the seasonal  
Citation: Berghiche A. COVID-19 and avian corona viruses: epidemiological comparison and genetic approach. J Life Sci Biomed, 2020; 10(3): 21-28; DOI:  
influenza vaccine. Also the permanent genetic mutations of this virus may lead to its weakening over time and  
climatic changes with the probability of increasing its mortality compared to its morbidity, and until the exact  
virulence profile and existing serotypes become evident. It is recommended to focus on the symptomatic  
treatment of secondary affections and prevention by confinement, which has proved its effectiveness as  
previous experience against this virus in chickens has shown its success in intensive farming known by its high  
population density  
To all the people who have suffered during this pandemic. To all the researchers who have published their  
results in order to open the chance for the researcher in the underdeveloped countries to participate in the  
scientific research even theoretically and specially dedicated to my friend Mister Ramy Adjailia for his help in  
the draw of the structural figure 1.  
Competing interests  
The author declares that he has no conflict of interests.  
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