Changes in antibody titres against Leishmania infantum in naturally infected dogs in southern Spain

Monthly serological follow-up of the antibody titres against Leishmania infantum in hunting dogs in rural southern Spain was carried out during the transmission period (from April to October in 1996), Titres greater than or equal to 160 were regarded as indicating disease, while lower positive titres were also recorded as 'seropositive'. Over this period, a significant (p < 0.05) increase in the percentage of dogs with a titre greater than or equal to 160 was observed; from 12.6% in April to 19.2% in October, The same pattern was observed with the seropositives (titre greater than or equal to 20) which increased from 36.3% in April to 55.6% in October, Of seronegatives in April, 60% were still negative in October whereas 22% had a titre of 20-40 and 18% had a titre greater than or equal to 80, Similarly, 68% of those with a titre greater than or equal to 80 in April still had a Citre in this range in October, 25% of the titre had decreased to 20-40 and in 7% to a zero titre, The most noteworthy is that 25% of animals reached titres of greater than or equal to 80 and decreased to zero or 20 more than once, Parallel to this study, another survey was conducted on dogs from Granada city centre, The seroprevalences (titres greater than or equal to 160) at the start and the end of the transmission period were 1.7 and 3.7% respectively and the seropositivety values were 12 and 11% respectively. (C) 1998 Elsevier Science B.V.