Validation of diagnostic tests for bovine babesiosis and anaplasmosis and studies on strain variation in Babesia

Malawi, Zimbabwe

Dr Thomas Dolan
Phone: 254 2 630 743
Fax: 254 2 631 499
Email: ILRI@cgnet.com

• Department of Veterinary Services, Zimbabwe
• National Veterinary Research Centre, Kenya
• Central Veterinary Laboratory, Malawi
• Queensland Department of Primary Industries, Australia

$85,000

30/04/1993 - 01/05/1995

N/A - 30/11/1995

Dr Denis Hoffmann

This grant operates within the ACIAR project 9118. The studies planned will include the collection and pooling of parasite material and bovine sera form a number of countries in Africa and from Australia. One aim is to establish a 'gold standard' serum bank for use in the development and validation of new diagnostic tests that will have international application. Another aim is to determine the degree of relatedness among parasites from different countries and regions, so that the feasibility of common approaches to control (such as a "standard" vaccine) can be assessed. ILRAD will provide laboratory resources needed for the collection, storage and analysis of these biological materials. The analyses will be undertaken by visiting Australian scientists.

The beginning of the project concentrated on the provision of sera and reagents from Australia for the validation studies of diagnostic enzyme-linked immunosorbet assays (ELISAs) for Babesia bigemina and Anaplasma marginala. Studies were extended to include Theileria parva and T.mutans at the end of the project. The B.bigemina antibody detection ELISA was developed at ILRI and was evaluated against sera from a number of B.bigemina endemic areas in Africa and Australia, and from areas in Europe and Australia where B.bigemina does not occur. Sera from Africa and Europe showed a high specificity and sensitivity, however cross reactions with Australian sera were also unacceptably high. Attempts are being made to reduce these cross reactions resulting in the validation of B.bigemina improved ELISA still not being complete. A field validation exercise involving a number of laboratories from Africa, Asia and South and Central America commenced at the end of 1994. The countries were provided with ELISA kits to be used to test sera collected from tick borne diseases (TBDs) epidemiological situations in each of the countries according to an agreed sampling frame. Validation was completed in Kenya and Mali, and is in progress in Brazil and India. Validation in Zimbabwe began in February 1996. In November and December ILRI ran a training course with FAO/IAEA and participants from eleven countries, to train them in TBD ELISAs. After completion of the validation exercise and analyses of tests of performance, the tests that have performed to the required standards were distributed for wider evaluation. Copies of the report on the performance of the tests will be sent to ACIAR and to the collaborators as soon as they are available.