Prevalence of Ectoparasite Infestation in Chicken in and Around Ambo Town, Ethiopia

In developing countries, animal production is being subjected to great pressure to satisfy the demand for animal protein required by the continued increase in human population, and also to have surplus for international trade. Among the animal production activities, poultry sector is the fastest growing. Nevertheless, it has been adversely affected by a variety of constraints [6]. Among the constraints, parasitism ranks top in village chicken production [7].


Introduction
Ethiopia accounts 42 million poultry population [1] from the total 18 billion of the world's population [2]. About 80% of poultry population in Africa and Asia are kept under free range system [3]. From the total population of chicken in Ethiopia, 99% are raised under the traditional back yard management system [4] with inadequate housing, feeding and health care [2,5].
In developing countries, animal production is being subjected to great pressure to satisfy the demand for animal protein required by the continued increase in human population, and also to have surplus for international trade. Among the animal production activities, poultry sector is the fastest growing. Nevertheless, it has been adversely affected by a variety of constraints [6]. Among the constraints, parasitism ranks top in village chicken production [7].
External parasites of poultry are common in the tropics because of the favourable climatic conditions for their development and the poor standards of poultry husbandry. Some of the ectoparasites are of particular importance as vectors of pathogens and host specific [8]. They can inhibit the skin or outgrowths of the skin of the host organism for various periods [9]. Some are blood suckers while others burrow in the skin or live on or in the feathers [10]. Ectoparasites, such as ticks, mites and fleas, live on domestic chickens. Mites have long been recognized as a cause of dermatitis and skin damage on all classes of poultry [11].
Despite their devastating effects, ectoparasites received little attention in almost all the production systems. Hence, study with regard to determining magnitudes of such parasites and identifying their types is fundamental to devise appropriate control methods [12]. However, no studies were conducted on poultry ectoparasites in and around Ambo town, Ethiopia, where chicken are source of income generation and food. Thus, the current study was undertaken to determine the prevalence of chickens' ectoparasite, identifies species of ectoparasites infesting chicken and assess potential risk factors.

Study area
The study was conducted from July to October, 2013 in and around Ambo town, West Shewa zone, Ethiopia. Ambo town is administrative center of West Shewa zone and Ambo district, and located at a latitude and longitude of 8°59'N 37°51'E8.983°N 37.85°E and an elevation of 2101 meters above sea level (asl) and 114 Km west of Addis Ababa, capital of Oromia region and Ethiopia. The agro-ecology of the study area is 23% highland, 60% midland, and 17% lowland. It has an annual rainfall and temperature ranging from 800-1000 mm and 20-29 o c, respectively. The livestock population of the district includes 145371 cattle, 50152 sheep, 27026 goats, 105794 chickens, 9088 horses, 2914 donkeys and 256 mules [13].
Even though there is some initiation for semi-intensive and intensive farming system, traditional farming system is still the dominant. Both local and exotic breeds chicken are raised in the area with predomination of local breed.

Study design and animals
A cross sectional study was conducted on a total of 390 local and exotic (Rhodes Island Red (RIR)) breeds from both sexes of chickens. The chickens were randomly selected from backyard chickens and selected semi-intensive farms. Information on the breed and management system was obtained from the owners and by assessment. Age of the chickens was determined by observing color of the shank and growth of the spur and categorized as young (less than 12 weeks of age) and adult (greater than 12 weeks of age).

Study protocols
All parts of the chickens were thoroughly inspected using naked eyes and hand lens. Ectoparasites were collected by hand picking and nontoothed thumb forceps. The collected parasites were further examined by light or stereomicroscope and identified according to guidelines of William [14]. Shank scraps were collected on clean petri-dish. Wet film was prepared from the scrap and 10% potassium hydroxide was used to emulsify debris and examined under light or stereomicroscope.

Data analysis
The collected data were coded and entered in to Microsoft Excel spread sheet and analyzed using Statistical software for Social Sciences (SPSS) version 16.0. Frequency was used to calculate the prevalence. Chi-square was used to test the statistical significance difference between the risk factor groups in prevalence of ectoparasite infestation. Odd ratio was used to estimate risk in groups of risk factors at 95% confidence interval (CI). P-value less than 0.05 (p<0.05) was considered as statistical significance difference.
Pediculosis (52.1%) was the most prevalent (  extensive management system were frequently infested while no chicken kept under semi-intensive management system was infested by ectoparasite. Prevalence, presence or absence of statistical significance difference in prevalence of each species of identified ectoparasites and the risk estimate for variables are given in Table 4.

Discussion
Ectoprasites are important constraints to poultry production sector. Some parasites exist only on one defined area of the host's body while others can exploit wider range of hosts [15]. The observed overall prevalence of 67.95% of ectoaparasite infestation in the current study is comparable to 70.73% report from Meerut [16]. However, higher prevalence rate of 91.5% [5], 86.67% [17] and 100% [3] were recorded in East Shoa zone (Ethiopia), Bangladesh and Nigeria, respectively. The difference between the current and previous findings may be due to breed, seasonal, management, agroecological, and implemented methods of the disease control and prevention [18,19]. The current study was undertaken during heavy rainy season (July to October) while others like Belihu et al. [5] was conducted in dry and short rainy season.
Positive chickens were found to harbor one or more ectoparasite species. About 48.21% of the total examined chickens were found to be infested with more than one species while 19.74% were infested with single species. Slight higher mixed infestation (67.4%) was reported from Haramaya intensive poultry farm, Ethiopia [12]. From the positive chickens, about 70.94% and 29.04% chickens were infested with mixed and single infestation, respectively. However, 19% single and 81% mixed infestation were recorded in Iraq [20]. The observed variation in the proportion of single and mixed infestation would be related to difference of implemented management system.   Pediculosis (52.1%) was the most prevalent followed by flea infestation (44.36%) while mange (34.62%) was the least prevalent. The current study is consistent with report from Wolayta Soddo town, Southern Ethiopia, in which 88% lice, 16.5% flea and 8.1% mite was reported [19]. Similarly, highest prevalence of lice infestation (90%) was reported from Kenya [21]. This may be related to favourable climatic condition in tropics for their development [8].
Five species of ectoparasites, namely E. gallinacean, C. mutans, and C. heterograha, M. stramineus and L. caponis, were identified in the present study. Most of these species were reported from different parts of Ethiopia [5,12,19], Nigeria [3] and Bangeladesh [17]. This indicates widespread of these ectoparasite species.
Higher infestation rate observed in male than female chickens with presence of statistical significance difference in current study is consistent with finding of Belihu et al. [5]. According to Mekuria and Gezahegn [19] and Bala et al. [3], the infestation was higher in female than male group. Young chickens were more affected (74.5%) than adult chickens (61.79%) with 1.9 times greater probability to acquire the infestation. This result disagrees with the finding of Sabuni et al. [21] and Nnadi and George [7] where 100% and 92% of adult and young chickens were infested, respectively with statistical significance difference. Management difference in different study areas may attribute to such differences.
Local breed chickens (87.55%) were more infested than exotic breed chickens (26.4%) with statistical significance difference. Slightly comparable finding of 2.35% was reported from Debrezeit semiintensive farm [24] and 100% in free ranging chickens [3]. Local breeds are allowed to free-range, thus becoming more vulnerable to ectoparasitism than exotic breed, which are almost kept in indoor. In this study, the prevalence was nil in semi-intensive management system while it was 87.46% in extensive management system, which is similar with work of Mekuria and Gezahegn [19]. This is due to better measures and practices related to good housing, feeding and husbandry system applied in semi-intensive farms where exotic breeds are kept.
In the current study, young chickens group were found 1.9 and 1.932 times more likely to be infested with lice species and C. mutans than adult chickens category, respectively. The result agrees with findings Mekuria and Gezahegn [19] where young chickens were 5.2 times more infested than adult chicken group and disagrees with 2.8 times more likely infestation of adult chickens than young chickens with C. mutans.
In conclusion, infestation of chickens with ectoparasites was important constraint of in the study area. Five species of ectoparasites were identified. Sex, age, breed and management were important risk factors with statistical significance difference. Therefore, application of integrated control strategy, good management practices, creation of awareness and further detailed study were recommended in the study area.