Diagnosis and Treatment of Coronaviruses Infection
D. Diagnosis and Treatment
Diagnosis of human coronavirus infections is not attempted in many routine laboratories. They have fastidious growth requirement in cell culture, and the conditions caused by them are of minor clinical significance. The routine diagnostic procedures comprises of cell culture and serology.
Virus isolation - 229E and related strains can be isolated in roller culture monolayers of human embryonic lung fibroblasts, such as W138 and MRC5 cells. A virus CPE of small, round, granular cells is seen throughout the monolayer. Isolates can be confirmed by virus neutralization tests. OC43 related strains usually cannot be grown in cell cultures. Isolation has to be performed on organ cultures of human embryonic tissue such as trachea.
Serology - virus neutralization are the most frequently used tests. HI, CF and ELISA tests have been used. Most of these tests are not carried out in routine diagnostic laboratories. There is little, if any, antibody cross-reaction between strains of 229E and OC43.
Direct detection of virus - indirect immunofluorescence and ELISAs have been developed to detect the presence of coronavirus antigen in nasal secretions with differing results. The usefulness of indirect immunofluorescence has still to be established.
No antiviral drugs against coronaviruses are available and little research is being taken to produce any. However, vaccines against certain animal coronaviruses are available.
