Dissemination, Replication, and Trans-Stadial Persistence of Dugbe Virus (Nairovirus, Bunyaviridae) in the Tick Vector Amblyomma Variegatum

Timothy F. BoothNERC Institute of Virology and Environmental Microbiology, Oxford, OX1 3SR, United Kingdom

Search for other papers by Timothy F. Booth in
Current site
Google Scholar
PubMed
Close
,
Gordon M. SteeleNERC Institute of Virology and Environmental Microbiology, Oxford, OX1 3SR, United Kingdom

Search for other papers by Gordon M. Steele in
Current site
Google Scholar
PubMed
Close
,
Anthony C. MarriottNERC Institute of Virology and Environmental Microbiology, Oxford, OX1 3SR, United Kingdom

Search for other papers by Anthony C. Marriott in
Current site
Google Scholar
PubMed
Close
, and
Patricia A. NuttallNERC Institute of Virology and Environmental Microbiology, Oxford, OX1 3SR, United Kingdom

Search for other papers by Patricia A. Nuttall in
Current site
Google Scholar
PubMed
Close
Restricted access

The dissemination and replication of Dugbe (DUG) virus and its tissue tropisms in the tick vector Amblyomma variegatum were examined by immunohistochemical analysis using specific antibody, in situ hybridization with a viral-complementary riboprobe, and infectivity assays of dissected tissues. Dugbe virus was localized in both unfed and feeding adults inoculated as nymphs or orally infected by capillary feeding, and in nymphs infected by capillary feeding. In non-feeding ticks, the main sites of DUG virus replication were the epidermis, hemocytes associated with loose connective tissue, and a small number of phagocytic digestive cells in the gut lumen. Virus infectivity in the hemolymph was associated entirely with hemocytes. Dugbe viral antigen or infectivity was not detected in the salivary glands until after the start of feeding. Viral titers in the salivary glands of feeding ticks were about ten-fold higher than in gut, ovary, or loose connective tissue. The level of infection decreased during molting and increased during feeding. Viral particles and pathologic effects were not detected in infected ticks. The primary site of trans-stadial persistance of DuG virus is the hemocytes. Tick hemocytes and other motile cells may be important in the transmission of persistent virus infection from one cell or organ to another by diapedesis.

Save