Herpes simplex virus types 1 and 2 in clinical infections: differences observed by electron microscopy

Area of Science:

• Virology
• Cell Biology
• Microscopy

Background:

• Herpes simplex virus (HSV) infections are common, with HSV-1 and HSV-2 causing distinct clinical manifestations.
• Accurate differentiation between HSV-1 and HSV-2 is crucial for appropriate patient management and epidemiological studies.
• Previous research noted unique ultrastructural features in cells infected with HSV-2.

Purpose of the Study:

• To evaluate the accuracy of electron microscopy (EM) in differentiating clinical isolates of HSV-1 and HSV-2.
• To determine if the presence of microtubule-like structures in infected cells can serve as a reliable marker for HSV-2 identification.

Main Methods:

• BHK-21/4 cells were infected with known strains of HSV-1 and HSV-2.
• Vesicular fluid from 50 clinical isolates (perioral, penile, leg) was used to inoculate BHK-21/4 cells.
• Infected cells were examined using electron microscopy to detect ultrastructural changes, specifically microtubule-like structures.
• Clinical isolates were also typed using indirect hemagglutination for comparison.

Main Results:

• Microtubule-like structures were consistently observed in BHK-21/4 cells infected with HSV-2 strains and clinical isolates from genital or leg lesions.
• Cells infected with HSV-1 strains or clinical isolates from perioral lesions did not show these microtubule-like structures.
• Electron microscopy typing results for clinical isolates perfectly matched those obtained by indirect hemagglutination.

Conclusions:

• Electron microscopy, by identifying microtubule-like structures, provides an accurate method for differentiating HSV-2 from HSV-1 in clinical samples.
• This ultrastructural marker offers a valuable diagnostic tool for distinguishing between HSV types, particularly for genital and leg lesion isolates.
• The findings support EM as a reliable alternative or complementary method to serological typing for HSV identification.