A direct agglutination test (DAT) for detection of visceral leishmaniasis in humans has been developed. In this study, it was evaluated for applicability to detection of infections in dogs, a reservoir species. The reliability of the test was improved by treating the test sera with 0.2 M 2-mercaptoethanol and incubating them at 37°C. Sensitivity was 100% and specificity was 98.9% when the test was used on serum samples from 220 dogs, including 26 with parasitologically confirmed canine leishmaniasis, 12 with suspected but unconfirmed leishmaniasis, and 182 with other conditions. The DAT detected specific antibodies in 10 dogs with canine leishmaniasis diagnosed by case history, clinical signs of leishmaniasis, and seropositivity in an immunofluorescence test using either promastigotes or amastigotes, as well as in 2 dogs suspected of having leishmaniasis. The performance of an antigen prepared from a homologous isolate of Leishmania infantum in the DAT was compared with that of an antigen from a laboratory-adapted strain of L. donovani (sensu lato). The homologous antigen compared favorably with the standard antigen, and the results provided further evidence of the potential of the DAT for detection of Leishmania infection in the canine reservoir host. The results of this study, together with those of our previous studies in human visceral leishmaniasis, demonstrate that the DAT is highly suitable for wide-scale epidemiological and ecological field work. This technique could also facilitate diagnosis of leishmaniasis in dogs in veterinary health services.

During the acute phase of babesiosis the direct identification of the causative agent is possible by examination of stained blood smears. An improved identification procedure for the diagnosis of Babesia bovis using DNA hybridization has been reported recently. For the diagnosis of both acute and chronic babesiosis, various serodiagnostic techniques have been developed. Recent advances in serodiagnosis designed for the detection of anti-Babesia antibodies were partly achieved by improving and standardizing the indirect immunofluorescence and complement fixation tests. The use of soluble antigens derived from Babesia culture supernatants or enriched, purified merozoites in the micro-enzyme-linked immunosorbent assay, solid phase radioimmunoassay and latex agglutination test has provided increased sensitivity and specificity in detecting anti-Babesia antibodies. Immunoblots and monoclonal antibodies have been used for the characterization and identification of babesial antigens and antigenic determinants. The advantages and disadvantages as well as the area of application of the currently available test systems will be discussed.

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Summary 26 farm cattle with suspected T. theileri infection as well as 5 calves experimentally infected with a culture‐adapted T. theileri isolate were examined for parasitaemia and antibody response in IFT and ELISA. For parasite detection the peripheral blood lymphocyte culture method (PBL‐CM) was more successful than the microhaematocrit centrifugation. The antibody response of experimentally infected animals could equally be detected by IFT and ELISA. For the detection of positive reactors among naturally infected cattle the IFT seemed to be more reliable. A skin test used for the demonstration of cellular immune reactions revealed specific delayed type hypersensitivity (DTH) after skin sensitization with T. theileri. In animals previously infected by the intravenous route, the skin test remained negative. In vitro exposure of T. theileri trypomastigote culture forms to diminazene aceturate (BERENIL®, Hoechst) resulted in a marked inhibition of the replication rate and motility of the parasites at concentrations of 50 μg/ml and above. Complete immobilization of the parasites could not be seen after 26 h of incubation with 200μg/ml of BERENIL®. A 3.5 mg/kg dose of BERENIL® for in vivo treatment of infected cattle showed only a slight reduction in blood parasite numbers 24 h after application, whereas 7 mg/kg reduced the parasite number beyond the detectable level within one day. Zusammenfassung Trypanosoma theileri Laveran, 1902, in natürlich und experimentell infizierten Rindern: Parasitennachweis — humorale und zelluläre Reaktionen — Wirkung von BERENIL® Bei 26 Rindern aus einem Bestand mit vermuteter T. theileri‐Infektion und 5 experimentell mit T. theileri (Kulturform) infizierten Kälbern wurde ein Parasitennachweis durchgeführt und das Auftreten spezifischer Antikörper mittels IFT und ELISA gemessen. Als Parasitennachweis erwies sich die Kultivierung peripherer Lymphozyten der Mikrohämatokritmethode überlegen. Die Bildung spezifischer Antikörper ließ sich sowohl im IFT wie auch im ELISA demonstrieren. Nach natürlicher Infektion scheint jedoch der IFT sicherer zur Erfassung seropositiver Reagenten. Nach vorangegangener Sensibilisierung der Haut mit T. theileri konnte mittels Hauttest eine zelluläre Immunantwort in Form einer Spätreaktion (DTH) nachgewiesen werden. Der Hauttest blieb negativ bei Tieren, die i. v. infiziert worden waren. In vitro‐Inkubationsversuche mit Diminazenaceturat (BERENIL®, Hoechst) zeigten eine deutlich reduzierte Vermehrungsrate und verminderte Beweglichkeit der Parasiten bei Konzentrationen von 50 μg/ml und darüber. Bewegliche Parasiten waren jedoch selbst nach 26stündiger Inkubation bei einer BERENIL®‐Konzentration von 200μg/ml noch vorhanden. Eine Behandlung von infizierten Kälbern mit 3,5 mg/kg BERENIL® i. m. bewirkte 24 Stunden nach der Verabreichung nur einen geringgradigen Abfall der Parasitenzahl, wohingegen nach Behandlung mit 7 mg/kg am folgenden Tag keine Parasiten mehr nachweisbar waren.

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