3 RETRIEVED EVIDENCE
Several studies were examined, and 31 citations were found from all the
databases: based on the inclusion and exclusion criteria, 8 experimental
articles were found relevant for systematic review (Figure 1). The
evidence from these 31 studies was identified to be of low (24
articles), moderate (1 article) and high (7 articles) standards. Eight
experimental studies were specific and relevant about providing hints
about the possibilities of ticks transmitting coronavirus like. The
seven experimental studies were sourced from Traavik and colleagues,
from the 1973s to 1978s, while one was obtained from Saikku and
colleagues, reported in the 1980s (Figure 1).
Studies by Traavik and colleagues at Runde Island, Norway during the
1973s, were initiated in the attempt to solve the mystery of unusually
high chick mortalities from seabird colonies reported. In the first
study efforts were made in the 1973s, where a collection of Ixodes
uriae samples from the seabird colonies and isolations of potential
tick-borne arboviruses were conducted. During the 1975s, the second
study was reported, where apart from the viruses isolates namely,
Tick-borne encephalitis and Uukuniemi group viruses, additional two same
strains of a coronavirus-like were found from I. uriae ticks
collected during the 1973s. This latter result leads to the collection
of Seabird sera samples, early May from Hernyken, RØst Island, Norway
(Traavik, Meel, & Kjeldsberg,
1977). During the 1977s, the third study was reported, where the
coronavirus like strain was tentatively named Runde virus linked with
Seabirds and I. uriae . The virus was termed Runde virus after the
island name where the seabird colonies were situated
(Traavik, Meel, & Kjeldsberg,
1977; Traavik & Brunvold, 1978). Several more landmark studies
(Traavik, 1977; Traavik & Brunvold, 1978; Traavik, 1978,1979) were
conducted and reported in the 1977s and 1978s in the attempt to back up
the evidence of Traavik, Meel and Kjeldsberg (1977). Evidence from the
cohort study indicated that the isolation of a coronavirus like agent
transmitted transstadially and sustained for six months in I.
uriae , was thought-provoking
(Saikku, Main, Ulmanen, &
Brummer-Korvenkontio, 1980). There evidence is available, however
Saikku, Main, Ulmanen and Brummer-Korvenkontio (1980), work does not
overwhelmingly support the findings of Traavik, Meel and Kjeldsberg
(1977); due to the lack of resources (for example, RT-PCR, RT-qPCR
molecular analysis and metagenomic sequencing) four decades ago.
Nonetheless, the ecological conditions of the isolations designated a
coronavirus circulating among the I. uriae and its seabird hosts.