If there was contact between the Aboriginals and travellers/merchants from these Eurasian–African countries, this should have given the Aborigines immunity to some Old World diseases. Is there evidence of such disease transmission in Australia?
The Indian Ocean trade was very large and much more diverse and profitable than any other trade route at that time, including the silk road. Trade ports from East Africa (including the Kilwa Sultanate, Ethiopia and the Swahili Coast), the Islamic World (Middle East, Egypt, and Parts of Africa), India, China, and Southeast Asia (including the Srivijaya and Mahajapit empires, and mainland Southeast Asia) got richer and better at seafaring. This lead to great seafaring technologies.
The Swahili Coast, Srivijaya, Mahajapit, and many more kingdoms along the Indian Ocean came about due to this reliable trade. These kingdoms definitely knew about Australia, due to its proximity from Indonesia and how great exploration was at that time. Were there any tribes that were resistant to European diseases?