Abstract:
The purpose of this study was to investigate prevalence and intensity of blood parasites in pigeon with local and seasonal variation. 450 pigeons in 5 sites, consisted of 3 sites in Bangkok (Lumpinee Park, Sanam Luang, and Dusit Zoo) and 2 sites in Chonburi Province (Sriracha District (Sriracha), and Muang District (Chonburi)) were studied in 3 periods: in rainy season (June-July 2000), in early dry season (November-December 2000), and in late dry season (February-March 2001). Haemoproteus columbae was the most common parasite in blood samples. There were only one trypanosome and one microfilaria in pigeons during February-March from Dusit Zoo and Sriracha, respectively. Both pigeons were virtually free from H. columbae. During June-July and November-December, prevalence of H.columbae in pigeons sampling from Dusit Zoo was the highest (100%, n=30 in both season). During February-March, parasite prevalence in birds from Sanam Laung and Dusit Zoo were the highest (96.67%, n=30 in each groups). From the results of Chi-square test, there was no significant difference of parasite prevalence in any site and any season. Results from Median test showed that H.columbae intensity during November-December and February-March were no significant differences in each site, however there was an statistically significant difference in each site during June-July (df=4, P=0.003). Besides, parasite intensity in the same site was no significant difference in any season. Consequently, parasite intensity during June-July was examined by Kolmogorov-Smirnov test. It was found that number of pigeons with heavy infection from Sanam Luang and Lumpinee Park were more than Dusit Zoo and Chonburi; and number of pigeons with heavy infection from Sriracha was more than Chonburi. In this study, morphological data are not directionally correlated with parasite intensity. The trend of immature parasite intensity increases with high humidity (rs=0.296, P=0.005), and high precipitation (rs=0.292, P=0.005) and decreases with high temperature (rs=-0.296, P=0.005). It can be concluded that the climatic condition in different sites is likely to be the main reason for heavy infection of parasites
