CLINICO-PATHOLOGICAL INVESTIGATION OF CHICKEN COCCIDIOSIS AT DIFFERENT UPAZILA IN BOGURA DISTRICT

Received 05 July, 2020 Revised 18 August, 2020 Accepted 22 August, 2020 Online 31 August, 2020


INTRODUCTION
In Bangladesh, Poultry industry plays an important role in the rural socio-economic system by contributing significantly on economic growth and simultaneously creating numerous employment opportunities. The contribution of livestock sub sector on GDP comes about 1.54 % (Bangladesh Economic Review, 2018). In the rural area of Bangladesh more than 65% family rears poultry and the poultry population in Bangladesh is only 215.00 million (BBS, 2017). A total of 5 million people are engaged in this sector (Saleque, 2007). At present chicken contributes 51% of total meat production in Bangladesh (Raha, 2007). Poultry industry is an emerging agribusiness in Bangladesh but there are several constraints for the establishment of this sector among them, various infectious and non-infectious diseases is one of major constrains for profitable poultry production. Outbreak of infectious disease causes economic loss and discouraging poultry rearing (Das et al., 2005). On an average, 30 % poultry birds die annually in Bangladesh due to outbreak of several diseases (Ahmed and Hamid, 1992). However, several diseases cause much reduction in the growth rate of chicken. One of these diseases, chicken coccidiosis is responsible for immunosuppression in the host (Candra, 2013). The economic significance of coccidiosis is attributed to decrease production with higher feed conversion, growth depression and increased mortality and the cost involved in treatment and prevention, (Peek & Landman, 2011). Coccidial infection can brings a great loss to poultry industry.
Coccidiosis is a protozoal disease in poultry, caused by the-Eimeria spp. belonging to the phylum Apicomplexa. Eimeria tenella is the most important species, as it causes caecal coccidiosis in chickens (Shirley et al., 1986). Intestinal coccidiosis caused by various species of Eimeria, is an economically important (estimated to be 2 billion dollars a year) disease of poultry (Zhang and Zeng, 2005). The mortality of young birds is predominant features. It is well known that poultry diseases are the major constraints for the developing the poultry industry (Karim, 2003). Poultry farmers face a wide range of diseases, which reduce the optimal productivity of poultry farms. Coccidiosis cannot even be controlled by vaccination due to mixed infestation of more than one species of Eimeria. Bogura is the northwest part of Bangladesh with different geoclimatic condition. Poultry diseases are the major constraints for developing the poultry industry in this region. Prevalence of coccidiosis may depend upon various factors such as geo-climatic condition, management system by farmers and vaccination etc. The actual picture of prevalence and pathology of chicken coccidiosis has not been worked out yet in this area and without the availability of some basic information regarding this disease problem, it is very difficult to encourage commercial farming in this region. Keeping these views in mind, the present work has been under taken with some objectives of determining the prevalence of chicken coccidiosis in relation to age group and variety of chicken with observation of clinical features and gross and histopathological changes of different organs developed due to chicken coccidiosis at different farm of Bogura district.

Experimental area and period
The study was performed in several small scale commercial poultry farm of different upazila like Sadar, Gabtali, Sariakandi, Sherpur, Shajahanpur, Shibganj, Adamdigi, Dhunat, Sonatala and Dhupchachia at Bogura district of Bangladesh and the laboratory examinations were conducted at the Department of Pathology and Parasitology of Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur. The experimental duration was 6 months from July to December, 2018.

Experimental Chickens
A total of 95 farms were visited and the number of chickens in the farms was variable ranging from 250 to 1250 and they were reared on litter. A total of 343 diseased and dead chickens including broiler, layer and sonali were subjected to this examination and the suspected chickens were grouped into 4 age groups such as group of 0-4 weeks, 5-6 weeks, 7-8 weeks and above 8 weeks.

Data collection and processing
A detail farm history in relation to the prevalence of disease including housing system, location of poultry farms, sources of chickens, age and population of the chickens per flock, rearing system, litter material, feeding and watering system, biosecurity of the farms, previous history of outbreaks, batch intervals and rearing systems were recorded. All collected data were recorded and analyzed with Statistical Package for Social Science (SPSS) software (version-22.00).

Clinical Examination
The general health condition and age of the chicken were recorded. The clinical signs were recorded during the physical visit of the affected farms and the farmer's complaints about the affected chickens were also considered.

Fecal examination for oocysts determination
Faecal sample was collected either freshly fallen faeces from the affected flocks or during the postmortem examination of the chickens, directly from cloaca with spatula. Samples were kept in glass vial containing 10% formalin. In laboratory, faecal samples were examined using two methods, Direct Smear technique and Floatation technique with standard protocol (Fowler and Miller, 1999).

Necropsy examination
The necropsy of the suspected dead and diseased chickens taken from different areas was done with established method and the gross morbid changes were observed and recorded carefully by systemic dissection. Some important samples (small intestine, large intestine, caeca and liver) were collected and preserved at 10% formalin for further histopathological study.

Histopathological examination
Formalin fixed samples were processed for paraffin embedding, sectioning and staining with haematoxylin and eosin according to standard method (Luna, 1968) for histopathological study. All images related to the present study were taken directly from microscope using different objectives manipulation of zooming system of a digital camera (Canon, 1XY, 16.1 Mega pixels, Japan).

Overall Prevalence of Coccidiosis
The study was conducted to outline the overall status of chicken coccidiosis in different small scale commercial farms of different upazila in Bogura district. Throughout the work, there were total 52 positive cases among 338 diseased and dead birds examination of different farms and the overall prevalence was 15.38%. Table 1 shows that there was no significant variation in the prevalence of chicken coccidiosis in different upazila and the prevalence rate were 13.33% in Sadar, 8.5% in Gabtali, 13.33% in Sariakandi, 14.63% in Sherpur , 20.00% in Shajahanpur, 16.67% in Shibganj, 20.00% in Adamdigi, 16.21% in Dhunat , 15.62% in Sonatala and 15.38% in Dhupchachia. Both Shajahanpur and Adamdigi upazilla show the highest prevalence rate (20.00%) whereas in Gabtali the rate was lowest (8.5%). The proportional mortality rates in different age groups were recorded as 19.25%, 21.42%, 8.23% and 7.5% in 0-4weeks, 5-6weeks, 7-8weeks and > 8week respectively which was significantly varied ( Table 2). Five to six weeks of age group prevailed the highest value (21.42%). Table 3 shows that the variety of chicken had no significant influence on the prevalence of coccidiosis and higher prevalence of coccidiosis was recorded in broiler (20.6%) than sonali (10.47%) and layer (10.25%).

Clinical Findings
Bloody diarrhoea is considered to be the most important clinical signs found in the examined chickens which was indicated blood mix with feces (Figure 1

Necropsy Findings
Major changes were recorded from different intestinal regions of examined chickens and there were enlargement and discoloration of caecum with numerous haemorrhagic spots, thickening of intestinal wall than normal, blood mixed intestinal contents representing reddish to brownish color in the intestinal lumen ( Figure  2. A), pin point to profuse haemorrhage was observed over the intestinal wall and mucosa (Figure 2. B).

Histopathological Findings
In histopathological section of caecum there was destruction of normal architecture of caecum, the mucosa of the villi were destroyed and disorganized and no continuation with lining epithelium of villi (Figure 3. A). In liver section, there was proliferation of fibrous connective tissue (Figure 3. B).

DISCUSSION
This total examination was undertaken to draw out the picture of prevalence of chicken coccidiosis at small scale commercial farm in different upazila of Bogura district with the observation of related pathological changes. Fifty two positive cases (15.38%) were found from 338 diseased and dead examined birds from several farms of Bagura district and there was a no significant relationship observed among the prevalence rate. The maximum prevalence was in shajahanpur and Adamdigi upazila on the other hand the minimum prevalence of coccidiosis was 8.5% which is founded in Gabtali upazilla. This observation is close to the data represented by other authors where they showed the incidence rate was 9.40% by Bhattachrjee et al.; 1996, 9.46% by Islam et al.; 2003. In West Bengal 85 (10.91%) cases of coccidian is recorded by Bhattacharya and Pramanik;1987. These variations among the present and earlier studies might be due to several geographical, management practices and some examination protocol such as study period, differences in sample collection techniques and identification procedure.
Young chickens are more susceptible and more readily display signs of disease, whereas older chickens are relatively resistant as a result of prior infection. The mortality rates found in different age groups were 19.25%, 21.42%, 8.23% and 7.5% in 0-4weeks, 5-6weeks, 7-8weeks and above 8week respectively with highest value in 5-6 weeks of age group. This reesult is similar to the observation by Kamath;1987, Rose;1999, Humphrey;1973 and Kogut et al.;. Typically, the disease is seen in chickens of 3-6 weeks old before they have acquired immunity. The exact cause of higher prevalence of protozoa in young than adult chicken cannot be explained properly but it can be hypothesized that younger chickens have less developed immune system compared to adults.
The present result shows that variety of chicken had no significant influence on the prevalence of coccidiosis where broiler (20.6%) shows the highest prevalence rate than sonali and layer. The present findings contrast with the observation of Etuk et al.; 2004 who recorded a higher prevalence of coccidiosis in adult layer chicken in other age categories which is different from this study. The variation may be due to location, season, age difference, sex, breed and other managemental factors. Clinical manifestation of chickens naturally infected with Coccidia was studied and the common findings were bloody diarrhoea, attachment of faeces around vent and blood mixed with feces. These findings are similar with the result of Reid and Pitoais;1965 and Williams;.Weight loss, reduction in egg production, damp litter and death occurs mostly on 5th or 6th day after infection were also found in this observation also agreed with the findings reported by Tyzzer;1990,Waxier;1998, Ruff et al.;1976 and Levine;1983. Gross pathological changes of the various organs of the affected chickens were studied and the major pathological lesions were deeper layers contained large areas of congestion, pinkish or blood tinged catarrhal exudates, hemorrhage and extravasations of blood within the intestinal lumen and intestinal mucosa. These gross lesions are also reported by Bertke;1989, Becker;1959, Reid;2002

CONCLUSION
The present work was conducted for the clinic-pathological investigation of chicken coccidiosis in different upazila in Bogura district based on clinical, parasitological, necropsy and histopathological feature. Total 95 farms were visited among which 343 diseased/dead chickens were examined out of which 52 chickens were found to be positive for coccidiosis. The proportion incidence of coccidiosis is lower because the farmers are intensively aware of coccidiosis and other parasitic disease now a day. They usually use coccidiostats routinely. The proportional mortality rates of coccidiosis in different age groups were significantly varied. The clinical signs of the affected birds were more or less similar to signs generally developed due to the infection with coccidiosis and clinically characterized as bloody diarrhea, anaemia, depression, ruffled feather, reduction of feed and water intake, drooping wings. At necropsy, deeper layers contained large areas of congestion, pinkish or blood tinged catarrhal exudates. Histopathologically destruction of normal architecture of caecum with destroyed and disorganized villi mucosa. On the basis of this examination, it is assumed that although coccidiosis is a serious problem for poultry production in Bangladesh but it possible to control under routine preventive and control measure which is prime essential for substantial improvement in poultry industry.