Ancient scripts in Ayurveda have dealt with the symptoms, types, curability and treatment for herpes disease using algae

शैवालं नलमूलानि गोजिह्वा वृषकर्णिका ||८४||
इन्द्राणिशाकं सघृतं शिरीषत्वग्बलाघृतम् |
(Visarpa Chikitsa 21st Chapter)
The paste of Saivala, the root of Nava, Gojihva, Vrsa- Karnika and leaves of Indrani (Nirgundi) are mixed with ghee and applied externally. Similarly, the paste of the bark of Sirisha mixed with Bala – Country mallow (root) – Ghrta may be applied externally. [84 ½ – ½ 85]

• Rajnighantu – Shalmalyadivarga
शैवलम् जलनीली स्यात् शैवलं जलजम् च तत्।
शैवलम् शीतलं स्निग्धं संतापव्रण नाशनं।

The following two quotations are often used in ancient medicine in Ayurveda:
Saivalmtuvaram tiktam madhuram sitalam laghu, Snigdhan dahtrisa pittaraktajvarharam param
-- Bhava Prakas
The algae are very efficient against thirst, body-temperature. They are soft and useful as they are sweet in taste.
In addition to the above points the later views about algae as drug plants is as follows:
Durvaakastputikkumbhikplavsaivalam.
Jalen kvathitan pitam sukrameh haram param
-- Chakradatta
The algae and several other things may be used as decoction to help against excessive night–fall and semen-discharge.