TICK-BORNE ARBOVIRUSES FROM MAGHREB

The problem of arbovirus infections in Maghreb has been relatively neg lected in the past in spite of a rich diversity of biotopes, the prese nce of potential reservoirs and vectors, and their position on the fli ght path of the Palearctic-african bird migration systems, western bra nch. Moreover, West Nile virus has been isolated from southern Algeria since 1968. From 1979 to 1989, tides were collected from wild birds, pigeons, bats, rodents, poultry, camels, wild boars, domestic mammals and man, and assayed for viruses. On the whole, 424 ticks were virolog ically studied from Morocco, 582 from Algeria and 601 from Tunisia. Fo ur tick-borne arboviruses have been isolated so far: three from Morocc o, Soldado (Nairovirus), Essaouira (Orbivirus) and Kala Iris (Orbiviru s) from Ornithodoros (A.) maritimus ticks parasitizing marine birds, a nd one from Tunisia, Tunis (Phlebovirus), from Argas reflexus hermanni infesting domestic pigeons. Soldado virus may infect man working into colonies of gulls for ornithological or entomological purposes and th is infection is associated with a self-limited febrile illness and pru ritus. In addition, antibody to Essaouira virus was detected in a wild rodent in Morocco. On the contrary it is unlike that Tunis virus may infect man because A. r. hermanni is a strickly ornithophilic tick. Ho wever, Uukuniemi group antibody has been previously evidenced in wild rodents in Tunisia. Finally, it is not excluded that other, more patho genic, arboviruses such as Congo-Crimean haemorrhagic fever might be a ccidentally introduced in this sensitive geographical area.