Arboviruses Isolated from Argas Ticks in Egypt: Quaranfil, Chenuda, and Nyamanini

Abstract

Summary Isolations are reported of three arboviruses designated as Quaranfil, Chenuda, and Nyamanini in the Nile Delta of Egypt. Quaranfil virus was isolated from Argas Persicargas arboreus, Argas (Argas) reflexus hermanni, nestling cattle egrets (Bubulcus ibis ibis), and a pigeon squab, and from the blood of two children during a febrile illness. The ecological characteristics of this virus deduced from virus isolation from naturally infected vertebrates and arthropods, limited surveys for antibodies, and experimental infection and transmission, suggest that it is essentially a bird virus, transmitted by Argas ticks. The two species of birds, the cattle egret and the pigeon, that were definitely incriminated, nested in colonies that were heavily parasitized by Argas ticks—the former by A. arboreus and the latter by A. r. hermanni. Apparently, infection is acquired mainly by the young birds from the infected ticks, and the birds in turn infect additional larval and nymphal ticks. Though the virus survived through moltings of the ticks, transovarian passage was not demonstrated. Evidence is presented for the occasional tangential infection of associated human populations. Chenuda virus was isolated from A. r. hermanni collected in two large pigeon houses, and presumably the pigeon is the vertebrate host. The low pathogenicity of this virus curtailed supporting experimental evidence on infection and transmission. Two strains of Nyamanini virus were isolated from A. arboreus and one strain from a nestling egret collected at a large rookery where Quaranfil virus was also isolated.