Coronaviruses in humans and animals: the role of bats in viral evolution

Abstract

Bats act as a natural reservoir for many viruses, including coronaviruses, and have played a crucial epidemiological role in the emergence of many viral diseases. Coronaviruses have been known for 60 years. They are usually responsible for the induction of mild respiratory signs in humans. However, since 2002, the bat-borne virus started to induce fatal epidemics according to WHO reports. In this year, the first serious human coronavirus epidemic (severe acute respiratory syndrome; SARS) occurred (China, 8098 cases, 774 deaths [9.5% of the cases] in 17 countries). The case fatality was higher in elderly patients above 60 years and reached 50% of the cases. SARS epidemic was followed 10 years later by the emergence of the middle east respiratory syndrome (MERS) in Saudi Arabia (in 2012, 2260 cases, 803 deaths [35.5% of the cases] in 27 countries). Finally, in December 2019, a new epidemic in Wuhan, China, (corona virus disease 2019, COVID-19) emerged and could spread to 217 countries infecting more than 86,255,226 cases and killing 1,863,973 people by the end of 2020. There are many reasons why bats are ideal reservoir hosts for viral diseases such as the tolerance of their immune system to the invading viruses for several months. They can actively shed the viruses, although they develop no clinical signs (will be discussed in details later in the review). Bats were directly or indirectly involved in the three previous coronavirus epidemics. The indirect transmission takes place via intermediate hosts including civet cats for SARS and dromedary camels in the case of MERS. Although bats are believed to be the source of COVID-19 pandemic, direct pieces of evidence are still lacking. Therefore, coronaviruses’ role in epidemics induction and the epidemiological role of bats are discussed. The current work also presents different evidence (phylogenetic data, animal experiments, bats artificial infection studies, and computerized models of SARS-CoV2 evolution) that underline the involvement of bats in the epidemiology of the pandemic.

Clinical, Biochemical and Molecular Evaluations of Ivermectin Mucoadhesive Nanosuspension Nasal Spray in Reducing Upper Respiratory Symptoms of Mild COVID-19

“…Coronaviruses are zoonotic viruses; SARS-CoV was transmitted from civet cats to humans and MERS-CoV from dromedary camels to humans. 1 The worldwide pandemic of Coronavirus Disease 2019 (COVID- 19), is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), first discovered in Wuhan, China in 2019. [2][3][4] Common manifestations of COVID-19 infection include respiratory symptoms, cough, fever, breathing difficulties and anosmia.…”

“…WHO recommendations to prevent infection spread include frequent hand washing, covering nose and mouth when sneezing and coughing, and avoiding close contact with anyone showing symptoms of respiratory symptoms such as coughing and sneezing. 1 There is currently no specific drug therapy or vaccine available to treat COVID- 19. Antimalarial drugs such as hydroxychloroquine and azithromycin, as well as antifilarial drugs such as ivermectin and antiviral drugs such as favipiravir, remdesivir, and umifenovir, have been studied.…”

Rapid determination of infectious SARS-CoV-2 in PCR-positive samples by SDS-PMA assisted RT-qPCR

“…As of June 30, 2021, over 180 million cases of COVID-19 have been reported, and more than 3.9 million lives claimed worldwide ( https://covid19.who.int/ ). Due to its fast spread and high mortality rate, scientists have worked on all fronts to characterize the virus ( El-Sayed and Kamel, 2021 ; Harrison et al, 2020 ; Yao et al, 2020 ) and reported clinical symptoms associated with the viral disease ( El-Sayed et al, 2021a , El-Sayed et al, 2021b ).…”

The contribution of bovines to human health against viral infections

“…BCoV causes respiratory and enteric infections in cattle (Clark 1993 ) while HCoV isolate OC43 the causative agent of common cold in humans. In 1937, avian infectious bronchitis (IB) was the first characterized coronavirus (El-Sayed and Kamel 2021 ). Human coronaviruses (HCoV) were identified in the 1960s and later, the bovine coronavirus (BCoV) in the 1970s (El-Sayed and Kamel 2021 ).…”

“…In 1937, avian infectious bronchitis (IB) was the first characterized coronavirus (El-Sayed and Kamel 2021 ). Human coronaviruses (HCoV) were identified in the 1960s and later, the bovine coronavirus (BCoV) in the 1970s (El-Sayed and Kamel 2021 ). To date, seven different CoVs have been identified in humans.…”