The diagnostic significance of the direct antiglobulin test (DAT) in anemic dogs

The direct antiglobulin test (DAT) was positive in 134 (36.1%) of 371 anemic dogs with internal diseases. Four principal types of reaction were recognized: IgG alone in 15 (11.2%), IgG + C′ in 41 (30.6%), C′ alone in 74 (55.2%) and IgM + C′ in 2 (1.5%). Rarely, IgM and/or IgA reactions occurred in association with strong IgG + C′ reactions. In 2 (1.5%) DAT-positive dogs the type of reaction was not clear. One or more symptoms of hemolysis, such as hemoglobinemia, indirect type hyperbilirubinemia, increased red cell osmotic fragility, and increased fecal urobilinogen excretion, were demonstrated in 84 DAT-positive dogs. These consisted of 10 of 15 dogs with IgG type DAT, 36 of 41 dogs with IgG + C′ type DAT, 36 of 74 dogs with C′ type DAT and 2 of 2 dogs with IgM + C′ type DAT. Most dogs with IgG + C′ type reactions had severe hemolysis, whereas “primary” or “associated” diseases were recognized in only 26 of 56 cases. IgG type incomplete warm antibody, reacting with pooled donor cells, was demonstrated in red cell eluates in each of 3 dogs with IgG type DAT and in 6 of 7 dogs with IgG + C′ type reactions. This indicates that dogs with IgG or IgG + C′ reactions usually have autoimmune hemolytic anemia. In dogs with C′ type DAT, indications of hemolysis were frequently minimal or absent. Symptoms almost always indicated some “primary” disorder. Diagnoses mainly included infections, inflammatory and neoplastic (especially myelo- and lymphoproliferative)diseases. In only 7 (9.5%) of 74 dogs with C′ type DAT no diagnosis other than (transient peracute) hemolytic anemia was made. The results of tests for antibodies in the serum and red cell eluates were always negative in dogs with C′ type DAT. In one dog with hemolytic anemia and C′ + IgM type DAT, there was a high titer of IgM cold agglutinins in the serum and in heat eluates. It is concluded that a positive DAT with anti-IgG antiserum is a strong indication of autoimmune hemolytic anemia but that a reaction of the C′ alone type is a rather common phenomenon in canine internal diseases which is seldom associated with serious hemolysis

Risk of infection with Leishmania spp. in the canine population in the Netherlands

The dog is the main reservoir of Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in humans in Southern Europe. In order to identify the risk of dogs from a Leishmania non-endemic area traveling to a Leishmania-endemic area becoming infected and the risk of transmitting infection to humans in non-endemic areas an investigation was performed, in which the results of a questionnaire were combined with the results of a serologic survey. The questionnaire was sent to 1478 at random chosen families in the Netherlands. Of the 59.0% responders 28.0% had one or more dogs and 4.8% of these dogs had visited Southern Europe during the summer period of that year. On a total population of 1,200,000 dogs in the Netherlands, this means that each year some 58,000 dogs are at risk of being exposed to a Leishmania infection in Southern Europe. During the period 1990-1992 blood was collected for serology in 1911 dogs presented to the Utrecht University Clinic because of clinical problems not related to leishmaniasis, of which 434 had been in Southern Europe in the foregoing years. None was serologically positive. From these data it can be deduced that the highest chance to obtain leishmaniasis during a vacation in Southern Europe is mathematically less than 1/434 or less than 0.23%. Serology was also performed during the period 1989-1993 in 597 dogs that had been in Southern Europe and were suspected of leishmaniasis. Titers were positive in 145 of these samples. Sixty-four of these dogs were born in the Mediterranean and had been imported into the Netherlands. Excluding these imported dogs, it was calculated that at least 0.027% of the 58,000 dogs yearly taken to Southern Europe during holidays become infected with Leishmania. In order to establish the risk of disease transmission for people in close contact with an infected dog, serum samples of owners and house mates of 37 dogs with leishmaniasis were tested. All 112 sera tested negative. It was concluded that the risk to get leishmaniasis was between 0.027% and 0.23% for the dog when taken to Southern Europe during vacation, and that the risk for owners in non-endemic areas to get leishmaniasis from an infected dog is minimal