Report of the Thirteenth Meeting of the OIE Ad hoc Group on Non Tsetse-Transmitted Animal Trypanosomoses.

The research article discusses the advancements in the study and diagnosis of Non Tsetse-Transmitted Animal Trypanosomoses (NTTAT), and highlights the developments in testing methods, vaccination response, and mechanical transmission methods for different strains of Trypanosoma in varied species.

Met Study and Integrated Field Programs

• There is a growing global interest in trypanosomoses that are not transmitted by tsetse flies, shown by increased research and field studies.
• Microbiology techniques have improved understanding of trypanosomes’ behavior. These advances have directly led to progress in diagnosis and immunology, and more rational methods for treating and preventing these infections.

Diagnostic Developments

• Field trials of enzyme-linked immunosorbent assays (ELISA) in Africa, Asia, and South America have proved their reliability in demonstrating antibodies or antigens for Trypanosoma evansi infection in buffalo, cattle, and camels.
• The same tests have been reliable for identifying mono-infection with T. equiperdum in equines. However, such specificity is currently lacking when there is a need to differentiate between T. evansi and T. equiperdum in equines.
• The card agglutination trypanosomosis test (CATT) has been adjusted to detect T. evansi infection and also shows promising results.

Interplay with the Immune System and Other Disease Conditions

• The immunosuppressive effects of T. evansi infection can decrease the immunological response to vaccination against Pasteurella haemolytica, making disease prevention more challenging in affected animals.

Investigations into the Mechanical Transmission of Trypanosoma

• In tsetse-free areas (Cameroon, Central African Republic, Zambia), it has been noticed that Trypanosoma vivax can also be mechanically transmitted by other biting insects, the identification of these vectors are currently being pursued.

Progress in Trypanosomoses Treatment

• Research concerning trypanocides led to the identification of the toxic factor for Trypanosoma brucei or T. equiperdum in human or simian serum, linked to high density lipoprotein of serum lipoproteins.
• Different derivatives are being tested under laboratory conditions, while some, such as ronidazole, are being validated for their effectiveness with other substances at the development stage (e.g. IMOL 881).
• Melarsomine, already commercially available for treating T. evansi infection in camels, is under study for potential use in other animal species.