J. Bangladesh Agri!. Univ. 6(1): 79-85, 2008 ISSN 1810-3030 Prevalence and pathology of haemoprotozoan infection in chickens A.R. Dey, N. Begum, Anisuzzaman and D. Chakraborty Department of Parasitology, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh Abstract samples Preva!ence and pathology of haemoprotozoan parasites in chickens were studied by collecting from randomly selected seventy five chickens from different areas of Mymensingh district, during July to December, 2007. In this study, 38 (50.66%) chickens were infected with haemoprotozoa of which 33.33% with Plasmodium sp., 12% with Leucocytozoon caulleryi and 5.33% with Leucocytozoan sabrazesi. The prevalence of haemoprotozoa was relatively higher in female birds (52%) than in male (48%), which was not statistically significant (P>0.05). The calculated odds ratio showed that females were only 1.17 times more susceptible to haemoprotozoan infection than male. However, age of the chickens influenced significantly (P<0.05) the prevalence of haemoprotozoa. Prevalence of haemoprotozoa was relatively higher in adult (>1 year) chickens (59.52%) than the young (<1year) chickens 39.39%. Adults birds were 2.26 times more susceptible to haemoprotozoan infection than young birds. Grossly the affected organs were apparently normal. However, in case of Leucocytozoon sp. Infection, infiltration of reactive cells and edematous fluid were found in interstitial space along with haemorrhages were detected in the alveoli of lung. Few muscle fibers showed large body similar to the schizont of Leucocytozoan sp. Comma shaped gamate of haemoprotozoa were seen in between the cord of hepatocytes in liver. Keywords: Plasmodium sp, Leucocytozoon caulleryi, Leucocytozoon sabrazesi, Pathology, Chickens Introduction Haemoprotozoa, protozoan parasites dwelling in the blood, are one of the important emerging threat in chickens. Although these parasitic problems have not yet been addressed and focused properly in Bangladesh. But many recent studies have been conducted on avian blood parasites in different countries of the world focusing their impact (Bensch et al., 2004; Hellgren et al., 2004; Ricklefs et al., 2005). In one survey 13.6% of backyard chickens in South Carolina were infected with Leucocytozoon caulleryi (Noblet et al., 1976). Haemoproteus (4.8%), Plasmodium (0.6%), Trypanosoma (2.0%) and Leucocytozoon (0.3%) were also reported from northwestern Costa Rica (Valkiunas et al., 2004). In many cases, mortality have been reported in domestic chicken (Garnham, 1966; Bennett et al., 1993 and Valkiunas, 2005). Leucocytozoon caulleryi is especially virulent, infected chickens frequently show severe sign of anorexia, ataxia, anaemia and dyspnea. Infected chicken may die because of haemorrhage which occurs as a result of rupture of megaloschizonts that may develop in all organs and tissues (Garnham, 1966 and Morii, 1992). The Bangkok hemorrhagic disease described by Campbell (1954) in Thailand which was probably due to L. • caulleryi. Plasmodium gallinaceum are most pathogenic for domestic fowl and may cause 90% mortality (Kemp, 1978). The exoerythrocytic stages of Plasmodium gallinaceum may block capillaries in the brain resulting death due to central nervous system dysfunction (Springer, 1997). Splenomegaly, anemia and nephritis have been reported in Plasmodium gallinaceum infection (Melhorn and Heydorn, 1978; Soni and Cox; 1975). Some haemoprotozoan infection has been reported in Bangladesh (Rahman et al. 1982) but detailed study has not yet been performed. In view of the above, the present research work was undertaken to study the prevalence and pathology of haemoprotozoa in chickens in Bangladesh. 80 Prevalence and Pathology of haemoprotozoan infection in chickens Materials and Methods Seventy five chickens were randomly collected from local markets and/or directly from farmer's house of different villages of Mymensingh district, from the period from July to December, 2007.After collection, age, sex, breed and body weight of chickens were recorded. Birds were examined carefully by parting of feathers against their natural direction and simultaneous close inspection to detect clinical signs, if any. Blood samples were collected by puncturing wing vein with the help of a sharp needle. The thin smear film was made immediately after the collection of blood. The smears were then air dried, fixed with absolute acetone free methyl alcohol, stained with Giemsa's stain and air dried (Cable, 1957). The slides were examined under microscope using high power objectives (40X and 100X) for the detection of 'blood protozoa. Identification of haemoprotozoa was based on the morphology as described by Levine (1985), Springer (1997) and Soulsby (1982). After ante- mortem examinations, affected birds were slaughtered and allowed to bleed completely and then routine postmortem examination was performed following the methods described by Fowler (1990). After the opening of thoracic and abdominal cavities, the lung, heart, liver, spleen, kidnies and ovary were examined carefully for the detection of pathological changes if any. Then lungs, liver, kidney and heart muscle were collected and fixed in 10% buffered neutral formalin for histopathological studies. Formalin fixed tissue samples were processed, embedded in wax, blocked, sectioned and stained with Haematoxylin and Eosin stains as per standard method (Luna, 1968). To compare the prevalence of haemoprotozoa in different sex group of chickens paired sample T-test was used (Mostafa, 1989). To determine the level of susceptibility of male and female chickens adds ratio/was calculated accroding to the formulae given by Schesselman (1982). Results and Discussion Prevalence of parasites in chickens: In this study, 38 (50.66%) chickens were affected with haemoprotozoa. A total of 3 species of haemoprotozoa were identified. Among the identified haemoprotozoa, prevalence of Plasmodium sp. was significantly (P<0.05) higher 33.33%, followed by that of Leucocytozoan caulleryi (12%) and Leucocytozoon sabrazesi (5.33%) (Table1). Similar studies were also conducted by Permin et al., (2002) who reported that 32% chickens were infected with haemoprotozoa whereas prevalence of Aegyptinella pullorum was 13% Leucocytozoon sabrazesi 4%, Plasmodium gallinaceum 14% and Trypanosoma sp. 5% in Zimbabwe. In Ghana Poulsen et al., (2000) found that 35% chickens were infected with haemoprotozoa such as: Aegyptianella pullorum (9%) and Plasmodium juxtanucleare (27%). According to Guo0ing et aL, (1998), the diseases were prevalent in Guangdong, Shandong and Fujian in China at the rate of 10.3%, 12.6% and 24.5 respectively in chickens These variation among the -present and previous studies may be due to the differences in climatic condition of the research area, availability of intermediate host, breeds of chicken, management system and methods of study. In this research work, only backyard chickens were included. Management system of the backyard chickens is relatively poor than any other system. Backyard chickens are easily and frequently affected by various arthropods like flies and mosquitoes, many of which act as vector of haemoprotozoa (Levine, 1967). The prevalence of male bird was 48% while in female 52% which was not statistically significant. This is almost similar to the finding of Poulsen et aL, (2000) who reported that there was no significant association between chicken sex and prevalence. The calculated odds ratio showed. that female chickens were 1.17 times more susceptible than the male chicken (Table 2). This result could not be compared due to paucity of relevant literatures. The exact cause of the higher haemoprotozoan infection in female chickens can not be explained. But in general, higher level of prolactine and progesterone suppress the immune system of the Dey et aL 81 individual and make the individual more susceptible to any infection (Lloyd, 1983). It was also revealed that the prevalence young birds ware 39.39% while in adult 59.52% the calculated odds ratio showed that adult were 2.26 times more susceptible than young birds (Table 2). Similar findings were reported by Guo0ing et al., (1998) who reported that in immune agar diffusion test, the positive detection rate of adult birds (10.9%) was much higher than that of young birds (2.8%). In this study, both L. caulleryi and L. sabrazesi were found in lymphocytes and Plasmodium sp. in RBC. In Plasmodium sp. infection, the detected gametocytes within the erytherocyte in Giemsa's stain, were round or irregular in shape with violet color pigmented granules which was present in cytoplasm. The host cell nucleus was displaced towards the peripheri due to the pressure of gametocyte. This description was almost similar to the description of Plasmodium sp. Oiven by Levine (1967) (Fig. 1). In L. caulleryi infection, the gametocyte which was identified within the lymphocyte, was round. The average size was measure 12 to 16p by 14 to 16 p. The nucleus of the host cell formed a narrow dark band extending about one third of the way around the parasite. The description was in the conformity with the descriptions of Leucocytozoon caulleryi given by Levine (1985) (Fig. 2). In L. sabrazesi infection, the appearance of haemoprotozoa which was identified from the peripheral blood of chicken were spindle shaped with long cytoplasmic horns extending beyond the parasites and measuring about 67 by 6,um. The host cell nucleus forms a narrow band along one side of the parasite. The mature gamonts were elongated and about