TOP1 and visceral leishmaniasis: Other TOP1B include the monkeypox virus TOP1 (mpxvTOP1), which is a conserved enzyme playing an essential role in the replication and spreading of the monkeypox virus [17,18], and the Leishmania donovani TOP1 (LdTOP1), that is an essential enzyme involved in the replication of the L. donovani parasite, the causative agent of the neglected tropical disease visceral leishmaniasis [19].