Abstract: From a major slaughter slab in Zaria, samples were collected from 250 domesticated pigeons and screened for helminths, ectoparasites and protozoan parasites. Eimeria sp. Haemoproteus columbae, Leucocytozoon sp. and Plasmodium relictum were the protozoan parasites encountered with 49.2, 15.6, 6.4 and 0.8% prevalence, respectively. Raillietina tetragona (4.9%), Raillietina cesticillus (3.0%), Raillietina echinobothrida (7.6%), Ascaridia columbae (1.2%), Ascaridia galli (1.2%) and Cappillaria anatis (0.8%) were the helminths seen, while Pseudolynchia canariensis (17.6%) was the only ectoparasite seen. The presence of these parasites were considered to pose a danger to achieving the full potentials of the up-coming pigeon barbecue business in Zaria.

INTRODUCTION

There is in the majority of developing countries an acute and growing shortage of animal protein. Jasiorowski (1972) reported that in developed countries an average daily per capital consumption of animal protein is 49 g as compared to an under nutrition of protein intake of about 11 g in the underdeveloped countries. The level of animal protein consumption in Nigeria is about 50% of the Food and Agricultural Organization (FAO) recommended standard and 30% of the British Medical Association requirement for developing countries. The inadequate supply of animal proteins for human consumption in underdeveloped countries is further aggravated by many prevalent factors limiting animal productivity within the affected countries.

Incidentally, the demand for domesticated pigeons (Columba livia domestica) is of late on the increase as indicated by records in slaughter houses and subsequently, displayed at barbecue spots in many urban settlements in Northern Nigeria. For now, it is a delicacy as its price is comparatively higher than those of beef, chevous and chicken sold at barbecue spots. Pigeons also rapidly attain table weight faster than the aforementioned meat sources, are easy to breed and keep, make relatively little noise and need little supervision and can are easily kept by novices. This therefore, suggests its increasing acceptability and perhaps gives pigeon the potential and puts it in an advantageous position to contribute significantly to this protein demand.

Poor animal husbandry systems, hazardous seasonal variations such as heat stress, diseases, malnutrition are only some of the factors preventing availability of increased animal protein in developing countries (Sekoni et al., 1988). Diseases are the most important limiting factors to livestock productivity in most sub-saharan African countries. Available reports show that pigeons too are often affected by diseases. Various parasites significantly impede pigeon growth, development and productivity, it at times result to death, especially, the squabs (Fatihu et al., 1991). Such sick birds are often slaughtered pre-maturely by the breeders instead of seeking for their cure. Previously conducted studies in Zaria were restricted mainly to helminths of pigeons (Audu et al., 2004). Information on the ectoparasites and protozoan parasites of domesticated pigeons in this region appears to be poorly documented. The current study was therefore, designed to provide holistic information on parasites of domestic pigeons, with the hope of designing an integrated parasite control for these birds, thus sustaining their increasing demand.

MATERIALS AND METHODS

Blood, faeces, gastro intestinal content and ectoparasites were collected from 250 domesticated pigeons taken for slaughter at the Zaria market slaughter slab. In recovering ectoparasites, the bodies of the birds were searched and thoroughly examined by separating the wings and separating the feathers so as to expose the skin. The ectoparasites found were collected and preserved in 70% alcohol. Approximately, 2 mL of blood was collected from each of the birds into sample bottles containing the 0.1 mg mL^-1 of sodium salt of Ethylene Diamine Tetra Acetic acid (EDTA). The bottles were rocked and rolled gently to allow for uniform mixing of the blood with the anti coagulant and thereafter screened for haemoparasites.

Faecal samples from all the birds were collected and put into differently labeled sample bags. As the digestive tract were dissected out, the trachea, esophagus, crop, proventiculus, gizzard, small and large intestine were each put in separate sample bottles containing 0.9% physiological saline. The lumen of each organ was thereafter, opened longitudinally to expose the content as described by Fatihu et al. (1991). Lower down the alimentary canal, faeces were checked for ova and oocysts. Adult parasites found in organs were all identified according to standard procedures (Soulsby, 1982). The ectoparasites collected were similarly subjected to standard laboratory procedures and subsequently identified.

RESULTS

The protozoan parasites encountered as indicated in Table 1, were Eimeria sp. (49.2%), Haemoproteus columbae (15.6%), Leucocytozoon sp. (6.4%) and Plasmodium relictum (0.8%). The cestodes were three species of Raillietina, which were R. tetragona (4.9%) R. cesticillus (3.0%) and R. echinobothrida. (7.6%), while the nematodes were Ascaridia columbae (1.2%), Ascaridia galli (1.2%) and Capillaria anatis (0.8%) as indicated in Table 2.

Table 1:	Prevalence of protozoan parasites in domesticated pigeons in Zaria. Number of birds sample (N = 250)

Table 2:	Prevalence of helminthes in domesticated pigeons in Zaria. Number of birds sample (N = 250)

Table 3:	Prevalence ectoparasites in domesticated pigeon in Zaria, Number of birds sample (N = 250)

Pseudolynchia canariensis was the only ectoparasite seen with the percentage prevalence of 17.6 (Table 3).

DISCUSSION

The result from this study showing Eimeria to occur in close to half of the pigeons (49.2%) is considered to be high (Lawal et al., 2001). The reason for the high prevalence may be due to the fact that the pigeons in this part of the country are mainly kept on free range and also the housing they retire to are raised mud huts. This offers optimal conditions of temperature and humidity for the sporulation of the oocysts. Although, species identification of the Eimeria was not done in this study, earlier reports in other places have indicated the presence of Eimeria labbeana in majority of the samples (Taylor et al., 2007).

There was a noticeable relationship between the prevalence of Haemoproteus columbae and its vector Pseudolynchia canariensis. The closeness in their percentage prevalence suggests that most of the vector harbored by the pigeons were probably carrying Pathogens. Higher percentages of Haemoproteus columbae and Plasmodium relictum in earlier studies could be due to differential parasite carrying capacity of the vectors and the differences in the seasons, in which the studies were carried out.

Although, clinical signs and mortality pictures were not the focus of this study, as samples were collected at the point of slaughter, anaemia, anorexia and high mortality has been reported especially, in squabs (Taylor et al., 2007). The presence of Plasmodium and Leucocytozoon in the blood of the pigeons was an indication of the presence of Culex and Simulium, respectively as they are established vectors of these haemoparasites (Taylor et al., 2007).

The presence of three species of Raillietina clearly support their cosmopolitan nature in chickens, guinea fowls, Turkeys, Pigeons, doves and bush fowls (Soulsby, 1982; Oniye et al., 2001; Audu et al., 2004). Ants of the genera Pheidole and Tetramorium, including various beetles, termites, flies and other arthropods, in addition to fruits and seeds form the major diets of dove and pigeon (Adang, 1999). The arthropod portion of the food, by carrying the infective stages, serves as intermediate host Mush et al. (2000). It may be therefore, right to postulate that the degree of prevalence is determined by levels of the infective stages present in the intermediate host and subsequently, their availability to the definitive host.

The three species of nematode encountered (Ascaridia galli, Ascaridia columbae and Capillaria anatis) were of low percentage prevalence. This is probably due to the mode of infection, as the infective egg dries off when the environment is harsh. Perhaps, most of the infective stages that got to the final host were through earth worms as transport host. There has also, been the suggestion of a possible migration of Ascaridia galli to the liver, trachea and lung to develop, rather than remain in the intestine (Michel, 1974). Despite their low prevalence, severe haemorragic enteristis, intestinal obstruction, reduction in egg production and subsequently death have been known to occur (Audu et al., 2004). The absence of Capillaria in the previous studies Oniye et al. (2001) and Audu et al. (2004) was probably due to variation in sample sizes.

From the parasitic fauna seen in this study, it is imperative to institute an integrated parasitic control through constant changing of litter, regular use of antihelminthics, anticoccidials and dusting of birds with pesticides. It is also, important to educate the breeders of these birds on the need to adhere strictly to these control measures. These, perhaps will boost the production of domesticated pigeon, consequently augmenting the animal protein required.

ACKNOWLEDGEMENTS

The researchers acknowledge the contributions of the Laboratory Technologists of the Department of Veterinary Parasitology and Entomology, Ahmadu Bello University, Zaria.